摘要:

ACETALS Dimethyl CITRATES TributylDiethyl TriamylACETATES Methyl DIBUTYL ETHEREthylPropyl LACTATES EthyButyl ButylAmy1 Amy1lsopropyl AcetateACETIC ACID MESITYL OXIDEACETIC ANHYDRIDE METHYL ETHYLACETI N S Monacetin KETONE DiacetinOLEATES EthylACETOACETIC ESTER ButylACETOACETAN l Ll DETriacet i nand i t s sodiumsalt OXALATES DiethylDi butylACETONEALCO H OLS Propyl PHTHALATES DimethylDiethylDi butylDiamylDihexylDioctylof Wood Naphtha type Lobosol F.S.Crotonaldehyde Lobosol M.A.Lobosol M.T.S.Lobosol S.S.Lobosol E.13ButylAmy1D i ace to ne2-Ethyl hexyALCOHOLDE N ATU RANTS SPECIAL SOLVENTSALDEHYDE-AMMONIAALDE HY OES AcetaldehydeAldol STEARATES ButylButyraldehyde Amy1Crotonaldeh ydeMetaldehyde TARTRATES DiethylParald e h yd e DibutylTAYLOR 209Write for List No.3059Some OpinionsICINGZETT’SCHEMICALENCYCLOPAEDIAA DIGEST OF INDUSTRIAL APPLICATIONSRevised by RALPH K. STRONG, Ph.D., Professor ofChemistry and Chemical Engineering, Rose PolytechnicInstitute, Terre Haute, Ind., U.S.A.7th Edition Pp. 1092 45s.“Kingzett has become an important reference book always to bekept in an accessible place” writes The Analyst. It was firstwritten in 1919 by the C. T. Kingzett, F.I.C., who realized the needfor a comprehensive digest of chemistry and its industrial applica-tions which would be useful as a work of reference by all classes ofchemists.“ It is without doubt the best one-volume work of its kind . . . . To those whodo not already possess this work we strongly recommend it as an indispen-sable part of their technical libraries.” -Chemistry and Industry.“ -411 chemists need a t times to consult a reference book covering the wholefield of chemistry.Such a need in handy and compact form is filled byKingzett.” -The Analyst.‘‘ The most valuable chemical work of reference of its size in English. 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Each book hassix colours printed inside, together with figures, arranged insteps of 0.3 pH.Invaluable to Chemistsand research workers.Descriptive leaflet free.JOHNSONS OF HENDON LTDLONDON, N.W.4 ESTABLISHED 1743-THE TECHNICAL PRESS LTD-IUST READY A Revised andEnlarged EditionWATER TREATMENTA Comprehensive Guide t o the Treatment of Water for all purposesand Effluents Purification.Sterilisation, Coagulation, Filtration,Storage of Industrial and Domestic Water. By G. V. JAMES,M.B.E., M.Sc.. Ph.D.,.F.R.I.C., Member of the Society of PublicAnalysts. Second Edition, Revised and Enlarged. Royal 8v0, Cloth.260 pages. Copiously illustrated. Price 30s. net.RECENTLY - CHEMICAL SYNONYMS& TRADE NAMESA Dictionary and Commercial Handbook. By WM. GARDNER,Works Chemist. Fifth Edition, Revised and Enlarged by E.1.COOKE, M.A., B.Sc.. A.R.I.C. and entirely reset. 564 pages. Con-taining approximately 28,000 Definitions and Cross References.Royal 8v0, Cloth. 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ISSN:0365-6217    

DOI:10.1039/AR94845FP001

出版商:RSC    

年代:1948

数据来源: RSC

摘要:

ERRATA.VOL. 44,1947.Page Line65 16 for 110.1 r d 101.1.103 15 * for R,.CC12:R2 read R1.CCl,-R2.114 5 * for 1935 read 1933.149196 2 * ~ O T -CH,.OH read -CH,.CHO.* From bottom of page.4 * reference 33, after 33 insert Y . R. Naves, A. V. Gram-poloff, and P. Backmann.€"TED IN GREAT BRlTALN BY RICFtARD CLhY A ? ? COMPANY, IiTD.,BUNQAY, SUPFOLK

ISSN:0365-6217    

DOI:10.1039/AR9484500004

出版商:RSC    

年代:1948

数据来源: RSC

摘要:

ANNUAL REPORTSON THEPROGRESS OF CHEMISTRY.GENERAL AND PHYSICAL CHEMISTRY.1. CHEMTCAL REACTIONS INDUCED BY IONISING RADIATIONS.1. Chemical changes produced in a photographic emulsion by theabsorption of rays emitted by a compound of uranium were the means ofBecquerel’s discovery of radioactivity in 1896 and are still used as atool in modern research in nuclear physics.2 Chemical changes broughtabout in living cells by X-rays are closely connected with the ensuingbiological effects, and are therefore of great importance in tlhe study ofradio therapeutic^.^^ It is the more surprising, therefore, that the mechan-ism of radiochemical reactions has until recently been so imperfectly under-stood. The reason for this is that the most obvious result of the absorptionof radiations from radioactive substances is the formation of ions, and, forabout forty years after Becquerel’s discovery, it was customary to ascribeall the chemical effects solely to the ion-pairs initially formed. The recog-nition of atoms and radicals in electrical discharges, and the growing realis-ation of the fact that molecular fragments are often much more reactivechemically when they are uncharged than when they are charged, havecaused a considerable reorientation of views about the way in which radio-chemical reactions proceed.A coherent account of this subject is thereforetimely.For the purpose of this Report, the subject of “ Radiation Chemistry ”will be defined as the study of the chemical effects produced by absorptionof all types of rays emitted in radioactive transformations, of quanta ofmagnitude greater than about 50 ev., and of electrons or positive ions ofthis energy range.Ions are formed in all these instances, but we excludeall photochemical changes (from which radiochemical changes differ, seebelow) even when these latter occasionally lead to i~nisation.~ Purelyphysical effects, such as radioluminescence, will not be discussed.Several monographs which deal particularly with earlier investigationsSee J. Becquerel, “ La RadiomtivitB,” Chapt. I, Paris, 1924.See, e.g., F. C. Powell et al., Nature, 1949, 163, 47.B. &I. Duggar, “ Biological Effects of Radiation,” New York, 1936.4 D. E. Lea, “ Actions of Radiations on Living Cells,” Cambridge, 1946.6 E.g., G.Volmer and K. Riggert, 2. phykkal. Chem., 1922, 100, 6026 GENERAL AND PHYSICAL CHEMISTRY.from the purely ionic point of view have been published,6-11 and the recentchange of outlook is most clearly seen in the proceedings of two recentsymposia,l2? l3 and in the second chapter of the late Dr. D. E. Lea’s2. Experimental Methods.-Reactions in discharges of all types havebeen fully discussed by G. Glockler and S. C. Lind.’ With the exceptionof the so-called “ gas electrode ” 21 all such reactions are restricted to gases,often a t low pressures in either static or flowing systems.The radiation may be supplied frorp a sourcesituated either inside or outside the reaction vessel. The use af externalsources, which include all high-voltage machines, is a dettermining factorfor the shape and material of the reaction vessel.Internal sources wouldminimise this restriction, but there are very few cases of their employment.A possible reason for this is the former scarcity of radioactive soqrces whichemit substantially one type of radiation. For example, radium, thoughavailable, can be used as a y-ray source only when the a- and p-rays areabsorbed in a screening material and can never serve as a pure a-ray source.(a) The principal positively charged rays are beams of helium nuclei,protons, and deuterons, all of which can be obtained from particle-acceler-ating machines such as the cyclotron and van der Graaff generator, Fndalready some radiochemical studies have been made by this means.14, l5Usually, natural radio-elements have been employed, e.g., (a) polonium,which emits only a-rays of 5.3 Me.v.energy,l6 ( b ) radon and its decayproducts, Ra-A and Ra-C’ mixed with the reactants.l7, l8 It is importantto use the source in such a form that it is not a chemical catalyst for thedestruction of the products.lg Other positive ions have occasionally beenused, for instance, I. Motschan et aL20 have used singly-charged alkali-s. C. Lind, “The Chemical Effects of Alpha Particles and Electrons,” Chem.Catalog Co., Inc., 1928.“ The Electrochemistry of Gases and other Dielectrics,” London, 1939.Lind, Chem. Reviews, 1930, 7, 203.2 (i). Radiation sources.13 W. Mnd, “ L’action chimique des rayons Alpha, en phrtse gazeuse,” Hermannet Cie., Paris, 1935.lo A. Kailan, “ Uber die chemische Wirkung der durchdringenden Radiumstrah-lung,” Vienna,, 1938.l1 F.Wegmiiller, “ Wirkung der Roentgenstrahlen auf einige organische Verbin-dungen,2’ Schuler, 1942.Symposium on “ Radiation Chemistry and Photochemistry,” University ofNotre Dame, June 24th--27th, 1947; J . Phys. Colloid. Chern., 1948, 52, 437.l3 Second Session of the Conference on ‘ I Certain Aspects of the Action of Radiationon Living Cells,” London, May 13th-14thy 1946 ; Brit. J . Radiol., 1948 Suppl. No. 1,41.l4 I. A. Breger, J . Phys. Colloid. Chem., 1948, 52, 551.l5 C. W. Sheppard and R. E. Honig, J . Physicat Chem., 1946, 50, 144; C. W. Shep-paxd and V. L. Burton, J . Amer. Chem. SOC., 1946, 68, 1636.l6 H. Folmer, Proc.K . AEad. Wetensch. Amsterdam, 1932, 35, 636.l7 P. C. Capron, Ann. 80c. sci. Brux., B, 1936, 55, 222.l8 L. H. Gray and J. Read, Brit. J . RadioE., 1942, 16, 125; 1941, 15, 380.l9 E.g., P. Bonet-Maury and M. Lefort, Campt. rend., 1948, 226, 1445.2o I. Motschan, S. Roginsky, A. Schechter, and P. Theodorof, Acta Playsicochim.U.R.S.S., 1936, 4, 757DAINTON : CHEMICAL RBACTIONS INDUCED BY IOWISING RADIATIONS. 'Imetal cations to induce the ammonia synthesis, and some of the changesobtained in aqueous solutions by V. I. Pavlov,21 using the so-called '' gas-phase anode '' method, are to be attributed to penetration of the solutionby positive gas ions of energy -103 ev. A novel recent development,which may prove valuable, is to use an external source of slow neutronsto irradiate a medium which can yield the required positive ions by anuclear reaction, I n this way, the advantage of an internal source wouldbe combined with that of the easier control of dosage which is associatedwith external sources.The met,hod has been applied to tissue,22 but the onlychemical reaction initiated in this way is the polymerisatian of styrene byrecoil protons and bromine ions formed by the Szilard-Chalmers reaction.23(6) Fast anions have rarely been used, the most important negativelycharged rays being electrons in the form of cathode or f3-rays. Wheneverexternal sources are used, the material to be irradiated should be in thefarm of thin layers, and, when a wall of a containing vessel has to be inter-posed between the source and the target, it should be as thin as is com-patible with the mechanical strain which it will be required t a bear.Ifthe soume is a radioactive element which is also cc-aetive, the thickness ofthe wall must, of course, exceed the range of the highest-energy cc-particleemitted. A common external @-ray source comprises radon " seeds," i.e.,thin-walled glass tubes containing radon gas, largely converted into anactive deposit of Ra-B and Ra-C.24 Many reinforced windows 259 26 madeof thin glass, aluminium, or mica, backed by fine wire meshes, have beendesigned for use with accelerating machines which operate a t low pressures,e.g., discharge tubes, van der Graaff generators. The choice of a windowmaterial will, of course, be partly determined by the nature of the chemicalreaction to be investigated.Internal @-ray sources do not appear to have been used-a fact whichis probably due to the lack of suitable naturally-occurring, purely @-emittingradio-elements, e.g., meso-Th-2, in adequate quantities. Increased avail-ability of artificial radio-elements such as 32P, and 204Tl may remedythis deficiency,( c ) High-energy photons, i .e . , X - and y-rays, possess a high penetratingpower, which is an advantage in that large samples can be adequatelyirradiated even when external sources are used. Disadvantagcs are (i) thatso much of the energy output of the source is wasted, and (ii) that con-siderable screening is required for the protection of personnel. All thework on y-ray-induced reactions has hitherto been effected by radium, -21 Compt.rend. Acud. Sci. U.R.S.S., 1944, 43, 236, 383, 385.22 P. A. Zahl and F. S. Cooper, Radiology, 1941, 3'5, 673,23 I. Landler and RI. Magat, Compt. rend., 1948, 226, 1720.24 A. T. Cameron and (Sir) Wm. Ramsay, J., 1907, 931, 1593; 1908, 966, 992.For n modern method of preparing radon " seeds " see Spicer, J. Sci. Instr., 1946,23, 207.2 5 See Chapter IV of ref. 7.28 W. D. Coolidge, J . Frunklin Inst., 1926,202,693 ; C. M. Slack, J . Opt. Sac. Amer.,1929, 18, 1238 GENERAL AND PHYSIUAL CHEMISTRY.in equilibrium with its decay products, and in a container of wall thicknesssufficient to filter out all a- and @-rays. The radiation thus emitted isnot monochromatic, but consists of eight lines varying in energy from0.189 to 2.198 Me.v. In contrast with the case of visible and ultra-violetradiation, the use of combinations of filters cannot lead to monochromatism ;it merely excludes much radiation of the longer wave-lengths.For maximumutilisation of the y-rays, the system to be studied is usually contained in achamber which has a central cavity for the source.27' 28 Other y-raysources of high energy and long life could be used, e.g., C'", 24Na, Y, lMSb,Mn, 85Sr, and Co.X-Rays are formed as scattered radiation when fast electrons fall on aprepared target, and consequently all machines which give electron beamscan easily be converted for use as X-ray sources. The X-ray beam con-tains quanta of all energies from very low values almost to the accelerationvoltage of the electrons, and becomes self-collimated more and more in theforward direction as this voltage is increased above 500 kv.In all X-rayexperiments reported hitherto, the source has been either specially con-structed or one of the convenient industrial units designed for radiographyor deep therapy.27~ z8( d ) Neutrons also bring about ionisation in the material in which theyare absorbed and have been used to initiate polymerisation.29 The highestneutron fluxes are most readily available as pile radiation, but this alsocontains a large proportion of y-rays.30 Alternatively, d,n reactions couldbe employed.312 (ii). Reaction vessels and temperature control. With internal sourcesof particulate radiation (K, p, etc.) the reaction vessel can be of any shapeand the reaction temperature controlled in the usual way by liquid orvapour thermostats. External sources require the use of very thin, butmechanically strong, windows [see 2 (i) (b)], and, since the range of suchparticles in dense media is very short," it is preferable to use only thinfilms of material to be irradiated. Such a reaction vessel cannot be totallyimmersed in a thermostat and furthermore, a good deal of heating of thespecimen and the adjacent window will occur.Reaction vessels for X-and y-ray work can be of much larger dimensions, and normal methods oftemperature control are possible.In order to meitsure the efficiency of the radiationin bringing about chemical reactions, it is essential to find the rate of energyabsorption in the medium.Convenient units are electron-volts (ev.) per2 (iii). Dosimetry.27 F. S. Dainton, J . Phys. Colloid. Chem., 1948, 52, 490.28 N. Miller, Nature, 1948, 162, 448.2s F. L. Hopwood and J. T. Phillips, {bid., 1939,143, 640.30 A. 0. Allen, J . Phys. Colloid. Chem., 1948, 52, 479.31 Ref. 4, p. 20.33 R. K. Appleyard, private communication.* E.g., the range of the a-particle from Po (5-3 a1e.v.) is 3.84 em. in dry air at 15"and 760 mm., but probably only about 3.42 x loda cm. in water.3mmfroN : CHEMICAL REACTIONS INDUCED BY IONISING RADIATIONS. 9litre per second. For internal sources of particulate radiation in reactionvessels which are large compared with the range of the particle, this (‘ doserate ” is readily calculable from the concentration, half-life, and 01- or (3-rayenergy of the radio-element employed.33 When the range is long, as isthe case in gas reactions, the calculation is more tedious.= When externalbeams of positive ions or electrons are used and all the rays reaching thereaction chamber are absorbed therein, the energy input can be estimatedfrom the beam current, the energy of the ions, and the stopping power ofthe windows.Although the absorption ofmonochromatic X - or y-ray photons is exponential with a coefficient char-acteristic of the energy of the photon and the absorbing substance, suchcoefficients are not readily determined.The reason for this lies in the factthat the energy is dissipated in the medium by photo-electrons and Comptonrecoil electrons [see section 3 (i) below].In the latter mecha,nism, there istherefore a good deal of scattered radiation, only a proportion of whichmay be absorbed. Nevertheless, it is possible 35 to calculate the ratio ofthe absorption coefficients of any two media for a given wave-length, providedtlhat their chemical compositions are known.In practice, most estimates of the dose rate are based on measurementsof the amount of ionisation produced either in the reacting system itself,if this is gaseous, or in an air-filled ionisation chamber. The method islimited by the difficulty of obtaining saturation currents in certain media.It is known that the mean energy dissipated in air at N.T.P.by electronsin creating an ion pair is 32.5 ev.36 and hence the rate of ionisation gives ameasure of the number of ergs absorbed. It is customary to define thatquantity of radiation absorbed by 1 C.C. of dry air a t N.T.P. which produces1 E.S.U. of charge (2.1 x lo9 ion pairs) as 1 roentgen; 1 C.C. of any othermedium placed in the same position relative to the same source wouldabsorb more energy, in the ratio of its volume absorption coefficients relativeto that of air. The relative number of ion pairs formed will also be inthis ratio if the same energy is required to create the ion pairs in thetwo media. In practice, the us0 of air-filled ionisation chambers in y-raydosimetry is not a simple problem, because almost all the ions formedin the small air cavity of the chamber are produced by the secondaryelectrons ejected from the walls of the chamber by the quanta which areabsorbed or scattered therein.The implications of this for accuratedosimetry of aqueous solutions have been discussed by L. H. Gray36 andN. Miller.37I n principle, some of the difficulties of dosimetry could be avoided byusing a reaction which is easily measured and the amount of which bears aX- and y-Ray dosimetry is less certain.33 E.g., G. Glockler and G. B. Heisig, J . Physical Chem., 1932, 36, 769.34 E.g., G . Glockler and R. Livingston, ibid., 1934, 38, 655.35 Ref. 4, p. 345.36 Brit. J . Radiol., 1937, 10, 600, 721; Proc. Roy. SOC., 1936, A , 156, B T S .37 In the press10 GENERAL AND PHYSICAL CHEMISTICY.fixed relation to the dose, as an integral dosimeter.Several attempts toconstruct such dosimeters have been3. The General Features of the Primary Radiochemical Act.-It isunlikely that any radiochemical reaction proceeds in one act, in the sensethat the immediate consequence of absorption of some of the ene?gy of theincident radiation is the conversion of the absorbing reactant moleculeinto the product. It is therefore convenient,4l as in photochemical pro-cesses, to divide the reaction into two stages : the primary act of energyabsorption, and the secondary reactions which terminate in product form-ation. In accordance with U.S. practice the symbol -+ will be usedfor the primary process.3 (i). The mechanism of energs absorption.Positively charged ionspassing through matter lose most of their energy by elastic impacts withelectrons lying in their path. The gross disparity in mass of the collidingspecies means that the ion loses little velocity and is virtually undeflected,whilst the electrons may be ejected from the atoms to which they arebound, frequently with sufficiently high velocities to ionise other molecules.*Ion-pairs are thus formed along, or near, the track of the positively chargedions. Measurement of the total number of ion pairs per track and also ofthe number formed per element of length of the track (the specific ionisation)has established that (a) with x-rays, approximately 60% of the total numberof ions formed are due to the secondary electrons, ( b ) the mean energydissipated in a system per ion pair formed is about 30 ev., being independentof the velocity of the a-particle, but characteristic of the absorbing system,and (c) the specific ionisation is an inverse function of the velocity androughly proportional to the square root of the atomic weight of the sub-stance being ionised, when this substance is at some standard concentration.The theory of this process42 has been developed along classical lines byN.Bohr43 and quantum-mechanically by H. Bethe44 and F. B l o ~ h . ~ ~Unfortunately, no accurate numerical predictions can be made from thesetheories. Thus, that of Bethe requires knowledge of an “ average excit-ation potential,” which is difficult to obtain a priori and which is usuallyevaluated empirically.Moreover, the treatment is restricted to atoms,H. Fricke and S . Morse, Phil. Mag., 1929, ‘4, 129.W. Stenstrom and H. R. Street, PTOC. SOC. Exp. Biol. Med., 1935, 32, 1498.40 R. W. G . Wyckoff and L. E. Baker, Amer. J . Roentgenol., 1929, 22, 551.41 F. S. Dainton, Report C.R.C. 304 (1946), not classified. N.R.C. (Canada),Division of Atomic Energy. Also M. Burton, ref. 12, p. 568, and J. 0. Hirschfelder,ref. 12, p. 447.42 For a general account of the physics of this process see F. Rosetti, “ Elementsof Nuclear Physics,” London, 1937, and H. Bethe and M. 5. Livingston, Rev. Mod.Physics, 1937, 9, 246.43 Phil. Mag., 1913, 25, 10.44 H. Bethe, Handbuch derPhysik, 1933, 24 (i), 519.4 5 2. Physik, 1933, 81, 363; Ann. Physik, 1933, 16, 285.* When the ejected electron has a, very high velocity, say 1000 ev., i t is knownThe tracks of such rays may be seen m spurs on a-particle tracks in the as a S-ray.cloud chamberDMY'l'OY : CHEMICAL REACTIONS INDUCED BY IONISING RADIATIONS.11and hence tbe empirical Bragg additive law 46 must be used for problemsinvolving molecules.Electrons are of such low mass that, except when they possess extremelyhigh energies, they are frequently deflected. The associated tracks haveill-defined ranges and are curved, particularly at law velocities. Theexperimental results and the theory * concerning the specific ionisationare very similar to the a-ray case discussed above. The specifio ionisationis inversely proportional to the square of the velocity a t low velocities, andless dependent at higher velocities, passing through a shallow minimumbefore increasing slowly at energies >-1 Me.v. At low electron speeds,the specific ionistitian is proportional to the atomic number of the absorbingmaterial, but, due to the fact that the average excitation potential is alsopraportional to the atomic number, this proportionality does not holdamongst the higher elements.I n addition to the energy lost by elasticimpact, a, small proportion, which increases with the electron energy, islost by radiation as the electron is decelerated in passing through the fieldof the nucleus. This appears as a continuous X-ray spectrum (Bremstrah-lung), and loss of energy due to this cause may assume serious proportionsa t electron energies in excess of 1 Me.v., especially for systems containingelements of high atomic number.Whereas charged particles undergo a stepwise loss of energy, photonsare absorbed in a single elementary act and hence a beam of X - or y-raysof intensity I , will have fallen exponentially to a value I .. e-6d at a distanced, where E is an extinction coefficient characteristic of the wave-length andthe absorbing medium. A high-energy photon may be absorbed by one ofthree mechanisms,* each of which will make its cantribution to the totalValue of E . The first mechanism which is especially prominent for softradiation and absorbing media of high atomic number, is that of ejectionof a pboto-electron, which will have an energy equal to the magnitude ofthe quantum less the binding energy.Since the electrons most usuallyinvolved are those in the K shell, this binding energy may be considerable.Ultimately, this energy appears as a second electron, since one of the outer-shell electrons will fall into the vacant K orbit and a very soft X-ray maybe emitted or a second much slower photo-electron ejected (Auger effect).The sacond mechanism is Compton scattering, and in this the least-tightlybound electrons are the most likely to be ejected. The energy of theCompton-recoil electron depends on the angle of scatter, but it should benoted that the scattered photon may still have a very high energy andthat the chances of absorption of such quanta will not be large in systemsof small volume.Not all the energy of the incident quantum is dissipatedin the medium. The third mechanism is the creation of positron-electronpairs. This is only possible for photons of energy greater than 2moc2,where mo is the electronic rest mass and c the velocity of light, i.e., -1 Me.v.46 W. H. Bragg, " Studies in Radioactivity," p. 43, London, 1912. * Coherent scattering and nuclear interactian are here neglected12 GENERAL AND PHYSICAL CHEMISTRY.The photon is completely converted into an electron and a positron, betweenwhich the excess energy of the photon above 2rn,c2 is approximately equallydivided. The positron is quickly destroyed with another electron givingrise to a y-ray photon (so-called annihilation radiation) of much lowerenergy than the original photon, which is therefore absorbed by one ofthe two other mechanisms.The existence of these three possible types of y-ray absorption, each depend-ent on wave-length in a different way, makes determinat'ion of the extinctioncoefficient for each wave-length very complicated.The Compton scatteringcoefficients per electron, which are independent of atomic number, can becalculated from the Klein-Nishina formula.47 The total absorption co-efficient per g. can be measured and hence, if the chemical composition ofthe material is accurately known, the photoelectric absorption coefficientcan be evaluated by difference. The latter coefficients have been relatedempirically to wave-length and atomic number, and thus the total absorp-tion coefficient for a medium of such a nature that it cannot be measuredcan be calculated from the sum of the dculated Compton coefficient andthe empirical photo-electric ~oefficient.~~Whatever the magnitude of the y-ray wave-length, the energy of thephoton is converted, if only in part, into a fast electron, which will dissipatethis energy along its track by the mechanism already described.3 (ii).The mean energy to create an ion pair (W). The number ofion pairs formed per unit time in an ionisation chamber can be counted,provided that the system permits the attainment of a saturation current.If the rate of energy absorption is also known, the average amount ofenergy dissipated in the medium when an ion pair is formed ( W ) can bereadily calculated.Accurate values are known for a-particles in gases oflow dielectric constant and vary from 35 ev. in nitrogen to 20.8 ev. inxenon. The values for electrons 49 are of the same order of magnitude,but increase somewhat as the energy falls below 5 ke.v. The values forX- and y-rays should be those appropriate to the Compton-recoil electrons,or photo-electrons. These values have been critically discussed byL. H. Gray,36 who selected 32.5 ev. as the appropriate value for air.Itspractical significance lies in the fact that many systems, notably liquids,exist for which the rate of energy input can be determined, but in whichsaturation currents are unattainable. In order to find the rate of ion-pairformation and hence compute the ionic yield, a value of W must be assumed.This is usually taken to be the value for air, appropriate to the radiationemployed.I n the case of water, for example, the ratio of the volumeabsorption coefficients of air and water for X-rays can be calculated [seesection 3 (i)], and this will also be the ratio of the rates of ion-pair form-ation in the two media exposed to the same source under identical con-The value of W is of great practical and theoretical importance.4 7 0. Klein and Y. Nishina, 2. Physik, 1929, 52, 853.4 8 See Appendix t o ref. 4 for further details.49 W. Gerbes, Ann. Physik, 1935, 23, 648; 1937, 30, 169D..4TNTON : CHEMICAL REACTIONS INDUCED BY IONISINQ RADIATIONS. 1sditions, provided that WXH20 = WXair = 32-5 ev. On this basis, 1 roentgenof radiation corresponds to the formation of 2.1 x lo9 ion pairs c.c.-l inair and 1-8 x 10l2 ion pairs c.c.-1 in water. Unfortunately, the effect ofphase change on the value of W can be only conje~tured.~~Measured values of W for various gases vary only slightly from substanceto substance and are always considerably greater than, but apparently notsimply related to, the ionisation potential of the substance.The firstfact is not well understood. Attempts have been made to calculate valuesof W for nitrogen and neon,51 but the results are in poor agreement withexperiment. U. Fano 52 has attributed it to increased outer screening insystems which have high ionisation potentials.(a) Distribution.It has been remarked [section 3 (i)] that, for all types of radiation, ionisationtakes place along the track of some charged particle, that the ionisationdensity is larger the slower the particle and therefore increases along thetrack, and is larger for heavy particles than for lighter particles of thesame energy.The positive ions thus formed lie initially in the wake ofthe ionising agent. The ejected electrons will be scattered in all directions,and, if there are any molecular species present in the system, which haveelectron affinity, the scattered electrons will be captured after most of theirenergy has been dissipated. Such electrons may traverse considerabledistances before capture, and hence, very shortly after the ionising agenthas passed, its track will consist of a high concentration of positive ions,located in a narrow core, and a lower concentration of negative ions, spreadthroughout a larger volume.The steep concentration, and electrical poten-tial, gradients thus established will cause a general diffusion radially, andinterdiffusion leading to charge neutralisation (4.v.). The latter effect resultsultimately in the destruction of all the ions, unless the experimental arrange-ment is such that a clearing field is applied.62 The tracks of any fastsecondary electrons (&rays) will have much the same structure. Beforecharge neutralisation is complete, a finite interval elapses during whichboth types of ions may decompose, initiate chemical change, or act asnuclei for clustering of polarisable molecules. The elucidation of the natureof the primary act includes the identification of the ions first formed andtheir possible fates.(b) IdentiJication and stabiEity of positive ions.Depending on the bond-ing or antibonding character of the electron removed, ionisation may occuralone or may be accompanied by dissociation. The amount of energyThus G. W. Hutchinson(Nature, 1948, 162, 610) states that W for Ra-G y-rays in liquid argon is of the sameorder 8s the value for gaseous argon, Le., 25 ev. N. Davidson and A. E. Larsh (PhysicalReview, 1948, 74, 220) have observed the ionisation of liquid argon by Po a-rays.F. L. Mohler and L. S . Taylor ( J . Res. Nat. Bur. Stand., 1934, 13, 663) give W = 24 ev.for liquid CS, using 0.27-~. X-rays. Saturation currents have been measured in hexaneand light petroleum by W.Stahel (Strahlentherapie, 1929, 31, 582).3 (iii). The charged species formed in the primary act.50 Estimates of TY for liquid phases have been made.51 E. Bagge, Ann. Physik, 1937, 30, 72.52 Phpsical Review, 1946, 70, 44. 53 Ref. 7, p. 36314 GENERAL AND PHYSICAL UHEMISTRY.expended in the various cases will differ, and ionisation potential data aretherefore of great value. Since in many cases a conaiderable proportion ofthe ions formed are due to impact by electrons of moderate velocities, muchinformation is to be gained from conventional mass-spectroscopical studiesof the ions formed by electron impact at various energies and pressures.Glockler and Lind 53 have summarised much of the data up to 1938 andF.S. Dainton27 has discussed the special case of water vapour where themost important ions are H20+, H+, and OH+. As formed, such ions maybe metastable and will therefore decompose very rapidly. For instance,J. A. Hipple, E. U. Condon, and co-workers 54 have shown that many ofthe ions of saturated hydrocarbons dissociate unimolecularly with halflives of the order of 10-6 see. into free radicals and carbonium ions or intoa paraffin molecule and an olefin ion. Thus, C4HI0+ --+ CH, + C3H,+ or ---+ CH, + C,H,+, and the carbonium ions may spontaneously dehydro-genate, e.g., C3H7+ -+ C,H5+ + H,. Alternatively, the positive ion mayreact with a neutral molecule, either in an electron-transfer reaction whenthe ionisation potentials are suitable, e.g., N2+ (17 ev.) + NH, (11 ev.) ---+N2 + NH,+ + 6 e ~ ., ~ ~ or in a mass transfer, e.g., H20+ + H,O + H30+ +When fast nuclei are employed as the radiation, some of the ionisationis of a primary character [see 3 (i)] and the relevant information in thiscase will no doubt be forthcoming from mass spectrographs, now beingdeveloped, in which the ionisation occurs by impact of fast positive ionssuch as H f , H2+, He+.57 All mass-spectroscopical data refer to gaseoussystems at low pressures. There can be little doubt that, at higher pressuresor in condensed systems, aggregation of neutral molecules round ions willoccur. (see section 5) andshould be manifested in unusually small ionic mobilities. Such low mobilitieshave been observed,68 but could equally well be explained by ion-induceddipole forces established between the ion and the polarisable molecules inwhose vicinity they move.59(c) Negative iom60 Electron capture by neutral atoms and moleculesonly occurs with slow electrons and when the neutral entities have appreciableelectron affinity.Unfortunately, there are few mass-spectroacopical data,on negative ions, and most of the information is obtained from electron“ swarm ” experiments,Bl from which it appears that lC diatomic molecules54 J. A. Hipple, R. E. Fox, and E. U. Condon, Physicat Review, 1947, 69, 257,and earlier papers referred to therein.5 6 S. C. Lind, J . Amer. Chem. Soc., 1931, 53, 2423.66 H. D. Smyth and D. W. Mueller, Physical Review, 1933,43, 116.5 7 J.R. Keene, private communication.6 8 A. M. Tyndall, “ The Mobility of Positive Ions in Gases,” Cambridge, 1938.-0 ~ . 5 6In gases, these are known as “ clusters ’’ 6 ,AIso ref. 12, p. 456.L. B. Loeb, “ Fundamental Processes of Electrical Discharge in Cfmes,” NewH. S. W. Massey, “ Negative Ions,” London, 1938.York, 1939.61 A. M. Crovath, Physical Review, 1929, 33, 605; N. E. Bredbury, ibid., 1933,44, 883; F. Bloch and N. E. Bradbury, ibid., 1935,48, 689DAINTON : CHEMICAL REACTIONS INDUCED BY ION IS IN^ RADIATIONS. 15do not form negative ions. Even a l C molecule may capture an electron,provided that the electron has sufficient energy to dissociate the moleculeinto fragments, one of which is not in a state, and therefore becomesthe negative ion, e.g., C1, + e + C1+ C1-.A further possibility, which does not appear to have been investigatedexperimentally, is simultaneous formation of positive and negative ions.Such heterolysis would probably require more energy than homolyticfission of the same bond.I n general, less is known about negative ions and their formation, butthere is no reason why they should not undergo the same types of reactionas positive ions, namely, breakdown, ion-neutral molecule reaction, cluster-ing, and ultimately, charge neutralisation.3 (iv).The uncharged species formed in the primary act. (a) From theions. Uncharged entities - differing from the molecules of the absorbingmedium may be formed by breakdown or reaction of the ions in processeswhich have been discussed in 3 (ii).Charge-neutralisation processes are not well understood, but it is con-ceivable that these also may cause formation of atoms and radicals.Thenegative charge is unlikely to be a free electron, and we therefore restrictour discussion to ion-ion reactions. If the ions concerned are radical oratomic ions, their union could give a finished molecule, e.g., H+ + OH--+H,O, provided a third body is present. The energy released might bedegraded to heat energy or used to dissociate the third body. Alternatively,charge neutralisation may be achieved by ionic dismutation, e.g., C,H,- +H+ -+ C,H, + H,. Even in such cases there might be considerableenergy release. The net effect of any charge-neutralisation process will beto release, in a restricted locality, energy approximately equal to that putin when creating the ion pair.J. 0. Hirschfelder 41 has pointed out thatthis energy is likely t o be completely used in immediate dissociation of themolecule on which the energy is located, but, if the molecule has a largenumber of internal degrees of freedom, this energy may be slowly degradedto heat.72There are two powerful arguments for the view thatsome of the reaction is effected through uncharged intermediates. Thefirst is that W is always larger than the ionisation potential. The excessenergy, of the order 15 ev., must be dissipated in processes not leading toionisation. Such processes are likely to be electronic excitation of themolecules, and, in view of the magnitude of the energy involved, it is possiblethat some of the energy is used to excite the molecule to non-ionic repulsivelevels. Estimates of the effectiveness of this process are ~onjectural.~~The second line of evidence is that H.Essex and co-workers 62 have shownthat the rates of decomposition of nitrous oxide and ammonia induced bya-rays are only slightly reduced when electrical fields are applied whichmaterially reduce the number of ions undergoing charge neutralisation.C. Smith and H. Essex, J. Chem. Physics, 1938, 6, 188; A. D. Kolumban andB. Essex, ibid., 1940, 8, 450; N. T. Williams and H. Essex, ibid., 1948, 16, 1153..(b) Directly16 GENERAL AND PHYSICAL CHEMISTRY.(c) Identi$cation of radicals and atoms. Mass-spectroscopic measure-ments are not of great value in identifying atoms and radicals formed inthe primary act, unless the appearance potentials can be accurately measuredand used to discriminate between radical ions formed directly and thoseformed by ionisation of radicals in the spectrometer.On the other hand,ultra-violet absorption and emission spectra should afford a valuable meansof identification, not only of atoms and radicals, but also of moleculesand ions. It has already been used to identify hydrogen atoms, andhydroxyl radicals in discharges through water ~ a p o u r . ~ ~ The study oflight emission from beams of high specific ionisation would be particularlyfruitful in that it would serve to identify any electronically excited species.Surprisingly few spectroscopic observations have been made on ionisingradiations, although the luminosity of such beams in air is well known.H.Greinacher 64 has reviewed previous work and has shown that theintensity of radiation from polonium cc-rays in air, carbon dioxide, hydrogen,or oxygen is unaffected by complete discharge of the ions, and increases withpressure, and that, with hydrogen, much of the light emitted is in theultra-violet region. E. Kara-Michaelova 65 has established that total lightemission of wave-lengths >2000~. per element of length of the track ofPo a-particles in air, varies with the distance from the end of the range asdoes the variation of specific ionisation.W. E. Burcham and F. S. Dainton 66 have photographed the spectra ofthe light emitted from an -600-kv.proton beam. Preliminary resultsindicate that excited nitrogen molecules are formed in air, but no resultshave been obtained as yet with water vapour or other gases. Work hasalso been reported on the light emission of pencils of a-rays passing throughmercury or sodium vapour in an excess of nitrogen or Noluminescence associated with excited species has been observed in liquids,although the Cerenkov continuum, which is produced when electronstraverse a medium with a velocity exceeding that of light in the medium, hasbeen investigated in detaiLB8 Chemical tests for atoms and radicals canalso be applied. Usually the existence o f such reactive intermediates issuggested by features of the kinetics of the reaction, e.g., very large ionicyields, or polymerisation.Atoms and radicals formed by rapid decompositionof metastable ions or by efficient reaction with neutral molecules will havean initial distribution very simiIar to that of the parent ions [section 3 (iii) (a)].63 K.Bonhoeffer and T. G. Pearson, 2. physikal. Chem., 1931, B, 14, 1 ; G. I. Lavinand F. 3. Stewart, Nature, 1929,123,607; 0. Oldenburg et al., J. Chem. Physics, 1939,7, 485, and earlier papers.(d) Distribution.64 2. Physik, 1928,47, 344.66 Sitzungsber. Akad. Wiss. Wien, R h s e 2A, 1934, 143, 15.6 7 A. Luyckx and J. Bodart, Physica, 1943, 10, 79.68 L. Mallet, Compt. rend., 1926,183,274 ; 1929,188,445 ; P. A. Cerenkov, PhysicaEReview, 1937, 52, 378; G. B. Collins and V.E. Reiling, ibid., 1938, 54, 499; H. 0.Wyckoff and J. E. Henderson, ibid., 1943, 64, 1 ; P, B. Weisz and B. L. Anderson,ibid., 1947, 72, 431,66 UnpublishedDAINTON : OHEMICAL REAUTIONS INDUCED BY IONISINQ RADIATIONS. 17Thus, all the radicals derived from positive ions will be situated along theaxis of the track, whereas those derived from the negative ions will bemore widely distributed. Uncharged species which are formed by directexcitation [section 3 (iv) ( b ) ] may be widely spread or confined to the centreof the track, depending on whether the lifetime of the excited levels of theparent molecule is long or short. Radicals which have their origin incharge neutralisation reactions will almost certainly be widely spread. Itis important to remember that those formed from metastable ions will becommonly of the same chemical nature when derived from ions of thesame charge, whereas direct excitation and charge neutralisation produceseveral radicals, not necessarily identical, which could, under suitableconditions, recombine to form the original molecule.The total number of uncharged species formed when acertain amount of energy is absorbed is of great importance.It is also avery elusive quantity and, like the quantum yield of the primary photo-chemical act, has an upper limit. For example, if H and OH are the onlyproducts of the primary act in water vapour, it is certain that not morethan six of each of these radicals can be formed per 32.5 ev. of energyabsorbed. The fraction of these which ultimately cause the observedreaction is probably less, and will depend on the nature of the reaction.Once the identities of the products of the primary act have been revealed,it should be possible to estimate their number from the magnitude of thereaction which they cause with a reagent of known rea~tivity.~'3 (v). The effect of the state of aggregation on the primary act.69 Thegreat increase in density associated with liquefaction will have severalimportant consequences. First, the methods available to identify the inter-mediates are almost exclusively chemical tests.Secondly, the primaryact may be profoundly affected.27 The specific ionisation will be muchhigher, and the mean energy, W , and ionisation potentials may be altered,although there is no direct evidence on the latter point.5O Deactivationalpossibilities will be enhanced and the persistence of, excited species willtherefore be less. If the liquid is polar, the effects of solvation will modifythe stability of any ions formed and their probability of being transformedinto radicals. Exothermic recombination processes, of ions and radicalsalike, will be facilitated by the nearness of third bodies. Immediaterecombination by the Franck-Rabinowitch rne~hanisrn,~~ of fragmentsformed from the same molecule by direct dissociation [3 (iv) ( b ) ] will alsoplay a part. The overall effect may be that the number of species capableof effecting decomposition of a pure liquid or reacting with a solute is muchreduced and that the products of decomposition of a pure liquid ariseprincipally from the radicals formed from the ions [3 (iv) (a)].The latterdistinction has been drawn in a somewhat different form and emphasis byA. 0. Allen in the case of liquid ~ a t e r . 7 ~See &o M. Burton, ref. 12, p. 575.(e) Number.70 J. Franck and E. Rabinowitch, Trans. Paraday SOC., 1934, 'SO, 120.71 Ref. 12, p. 47918 GENERAL AND PHYSICAL UHEMISTRY.Aply energy which is not used in chemical change or light productionwill appear as heat which will be manifested as a temperature rise.I?. H. Krenz 72 has detected this dilatometrically in the case of liquid waterirradiated with y-rays. A feature of this effect is its persistence far abouta minute after the irradiation is stopped.This after-effect is attributedby the author to the slowness of the degradation of the internal energyinto heat, which would be expected if the internal energy was originallyexcitational energy of complex units. Krenz identifies these units withwater polymers. The same lag would be expected in all associated liquids,not only as an after-effect, but also as an induction period to the expansion.Moreover, as the author points out, such lags should not be observed inrelatively unassociated liquids, but might occur when polymeric COM-pounds are dissolved in them. This behaviour is exemplified by benzene,which alone shows no lag, whereas 1% solutions of polystyrene in benzeneshow a short lag. These observations are of great interest and, if extended,might yield interesting information concerning the structure of liquids.It is to be hoped that the influence of temperature will be investigated,since this should reduce the number and complexity of the water polymers,but not affect the polystyrene solute molecules, and would thus discriminatebetween the two systems.8 (ti).A similar division into primary and secondary processes is madein photochemistry. The two subjects are similar only in respect of secondaryprocesses. In all other respects they differ very widely.734. Secondm Proceaes, Ionic Yield, and the cc Cluster '' !Cheory.-Inthe preceding section, emphasis was laid on the view that, chemically,the most important products of the primary act are the uncharged atomsand radicals.An alternative hypothesis, formerly widely held, is the'' cluster theory " in which uncharged species are disregarded and the ionsregarded as the more important, The essence of the cluster theory, asproposed by 8. C. Lind,0, 7 is that one or both members of an ion pairact as nuclei, to which neutral molecules are drawn and held as clustersby polarisation forces. Reaction was conceived as occurring on chargeneutralisation, all the molecules of the complex undergoing chemical changeand the requisite energy of activation being provided by the heat of neutral-isation. For example, the oxidation of methane was written as (02CH,02)+ +(0,-CH,O,) --+ 2C0, + 4H,O. Such a theory is clearly bapable ofaccounting for ionic yields slightly in excess of unity, and for the usualkinds of variation of M / N with pressure, since the size of the cluster willbe related to the initial pressure.In its simple form, specific ion clusterswere assumed and de~ignated,'~ but later work by W. M ~ n d , ' ~ E. K. Rideal,76and R. S. Livingston77 has been concerned with the nature of the inter-72 F. H. Krenz, Canadian J . Res., 1948, 26, 647.73 F. S. Dainton, Research, 1948, 1, 488.74 See, e.g., ref. 6, table VIII, p. 100.76 Troisibme CoszseiiE c h h . Solvay, 1928, 1.7 7 Bull. SOC. chim. Belg., 1936, 45, 334.7 6 Bull. SOC. chdrn. Belg., 1934, 43, 100DAINTON : CHEMICAL RBIACTIONS INDUCED BY IONISING RADIATIONS. 18action of the central ion with its surrounding molecules. The main evidencefor clusters has been recently reviewed.'*Whilst values of ionic yields calculated on the cluster theory are claimedto be in quantitative agreement with e~periment,'~ and whilst the averagedistribution in the system will include some aggregation of molecules aroundcharges, there are several major objections to adopting the cluster theoryas a general mechanism for radiochemical reactions.Thus, (a) Essex andco-workers 62 have shown that, under conditions where ion neutralisationis eliminated or considerably reduced, the ionic yield is only slightly affected,and ( b ) excitational processes leading to, and experimental evidence for,uncharged atoms and radicals known to induce the chemical change observedhave no place in the theory.In the ensuing pages the " atom-radical " theory of the primary actwill be most frequently employed and it will be assumed that the secondaryprocesses are merely those reactions into which the uncharged products ofthe primary a c t would enter whatever their mode of formation-thermal,photochemical, or radiochemical.This " carry over " of information fromone investigation to the interpretation of another has been discussed byE. W. R. Stea~ie.'~The number of reactions which have been stimulated by radiation isvery large and the reactions mentioned in this Report have been choseneither because the primary act is well understood and exemplifies principlesalready mentioned, or because the observed kinetics have no parallel withother modes of initiation, or because the reaction is intrinsically importantand recent work has clarified a previously obscure mechanism.5. Single Inorganic Substances (excluding Water).-The deoornpogitionof solid and gaseous inorganic substances has been extensively investi-gated.6, 7p No coherent theory exists for the former, except where thesolids can be detonated by impact, e.g., nitrogen tri-iodide and bariumazide.81 Hydrogen iodide has been studied in all three phases.82 In thegaseous phase the oxygen-ozone system,83 the oxides of nitrogen,s4 andvarious hydrides, e.g., NH3,62 ND3,85 HI 82 and H,S 86 have been muchstudied.A feature of many of these reactions is that the ionic yield exceeds78 R. S. Livingston and S. C. Lind, J . Amer. Chern. SOC., 1936, 68, 612; S. C. Lind,ref.12, p. 437, and J . Chern. Physics, 1939, 7, 790.70 Ref. 12, p. 441.M. Haissinsky and R. J. Walen, Compt. rend., 1939, 208, 2067; E. Feenberg,W. E. Garner and C. H. Moon, J., 1933, 1398.Physical Review, 1939, 55, 980.82 P. Giinther et aZ., Bev., 1943, 75, B, 2064; Giinther and Leichter, 2. physikal.83 S. C. Lind, Monatsh., 1912, 32, 295; P. C. Caprim and R. Cloetens, Bull. SOC.84 G. R. Gedye, J., 1931, 3016; W. Mund and R. Gillerot, BulE. SOC. c h h . Belg.,85 J. C. Jungers, J . Physical Chem., 1936,40, 155.86 W. Mund et al., Bull. SOC. china. Belg., 1934, 43, 49, 100; 1937, 46, 129; P. Gal-Chem., 1936, B, 34, 443 ; K. G. Brattain, J . Physical Chem., 1938,42, 617.chim. Belg., 1935, 44, 441 ; B. Lewis, J . Physical Chern., 1933, 37, 533.1929, 38, 349.mont, {bid., 1932, 41, 43130 GENERAL AND PHYSICAL OHEMISTRY.unity and is several times larger than the quantum yield of the correspond-ing photochemical reaction, which is strongly suggestive of more than oneradical being formed per ion-pair. 87The spin isomerisation of hydrogen under the influence of a-rays has avery large ionic yield, 800-1000, too great to be accounted for by clusteringand strongly suggestive of a chain mechanism.P. C. Capron l7 found therate of destruction of para-hydrogen by a-particles from radon in a sphericalvessel to be given by-d@H,]/dt = ke-lt. [pH,] . . . . . . (1)where A is the decay constant of radon. The ionic yield is therefore inde-pendent * of the dose rate and any reaction chain cannot undergo mutualtermination, a result which is somewhat surprising since in the high-tem-perature thermal conversion it is certain that the chains are stopped inpairs by recombination of hydrogen atoms.ss Capron therefore consideredthe possibility of the chain carrier being a proton, but, since no reactionsoccurred at -187", he suggested that a hydrogen atom is the effectiveagent.Reprodueible results were obtained in the presence of mercuryvapour which Capron found to be a retarding agent. These kinetic resultscould be explained by assuming the reaction sequence, (i) H, -A+- 2H,(ii) H + pH2 a OH,+ H, (iii) H + Hg --+ HgH, but H. EyringJ. 0. Hirschfelder, and H. S. Taylor 89 have calculated the equilibrium,constant of reaction (iii) and find that, at the partial pressures of mercuryconcerned, this reaction cannot be regarded as an efficient process forremoval of atomic hydrogen.They therefore conclude that the majortermination reaction is removal of atomic hydrogen a t the vessel walls.If a perfectly efficient wall removal was assumed and since the dimensionsof the reaction vessel and source, the velocity constant of the propagationreaction (ii),88 and the diffusion constant of atomic hydrogen throughmolecular hydrogen were known, a rate of formation of hydrogen atomscould be calculated which accounted for the observed reaction rates , pro-vided that six hydrogen atoms were formed per 33 ev. of w a y energyabsorbed.The most important feature of these authors' work is that it containsthe fist close theoretical analysis of a primary act.Equilibrium dis-tribution of doublet (H, H,+) and triplet (H, H,+H,) clusters are calculatedon reasonable assumptions, and the values indicate that larger clusters areimprobable. The ion H,+ is regarded as constituting upwards of 90% ofthe primary ionisation. The velocity constant of the reaction (iv), H2+ +H2-+ H,+ + H, is calculated to be 1.25 x 1015 C.C. mole-l sec.-l, andthis reaction therefore predominates at reasonable pressures. The neutral-s' Ref. 4, table XX; ref. 27, table I.8 s A. Farkas, 2. physikal. Chem., 1930,10, B, 419.89 J. Chem. Physics, 1936, 4, 479.? Note that Eyring et al. (ref. 4, p. 491) mistakenly remark that " the M / N yieldwas dependent on the radon intensity, etc.DAINTON : CHEMICAL REACTIONS INDUCED BY IONISINQ RADIATIONS.21isation reaction of H,+ with an electron is considered to yield between 2and 3 hydrogen atoms. Hence the total net yield of hydrogen atoms fromthe ion pair H,+ + electron is between 3 and 4 [cf. section 3 (iv) (a)]. Thepart of W (= 33 ev.) not used in ionisation is regarded as causing excitationof hydrogen molecules (lC + Q ) , a process which requires 12 ev., andresults in dissociation of the hydrogen into two hydrogen atoms.6. Binary Inorganic Mixtures.-When one component, the solvent, is ingreat excess, the products of the primary act will be derived largely fromthat component. When the chemical change observed is due solely toreaction of these products with the solute, it is referred to as "indirectaction" of the radiation [cf. section 3 (v)].Few examples are known ofindirect action on systems in which both components areHydrazine, a t concentrations of 0.05 to 0.1% in hydrogen, is reduced toammonia by the action of a-rays from radon, with an ionic yield of 3.91The mechanism suggested includes : H, --+ 2H ; N,H, + H + NH, +NH,; ZNH, + M + N,H, + M. Decomposition of hydrazine andhydrogen sulphide by indirect action is also possible in excess of nitrogen,but in this case the mechanism is less well understood. P. Gunther andL. Holzapfelg2 have studied the decomposition of ammonia, and thesynthesis of water, by indirect action of X-rays in an excess of xenon. Aradical mechanism is here difficult to formulate.Some of the reaction isdoubtless due to collisions of excited xenon atoms with the reactants andmay result in the dissociation of the latter. The point has also been madeby H. Eyring 93 that the xenon ion is electronically merely a very reactiveform of an iodine atom. Part of the reaction in this case might thereforebe represented as Xe+ + NH, -+ (XeH)+ + NH,.Most radiochemical reactions in inorganic mixtures are systems in whichboth reactants make their contributions to the primary act, which is there-fore rather complex. The reactions investigated include addition reactions,H, + C1, + 2HCl,94 H, + Br, =+ ~HBI-,'~, 95 H, + I, + 2HI,s2 CO 4-C1, ;." COCl,,96 CO + 0.50, CO,; 97 isotopic exchange reactions,e.g., H, + D, T+ 2HD; 98 and many oxidations, e.g., CnHzIl + , + 02,99N, +- O2.lo0 Many of these, particularly those involving halogens, haveThe first investigators to achieve indirect action through hydrogen were W.Duaneand G. L. Wendt (Physical Review, 1917, 10, 116).91 A. van Tiggelen, Bull. SOC. chim. Belg., 1938, 4'9, 577.98 2. physikal. Chem., 1937, 38, By 211.93 J . Chem. Physics, 1939, '4, 792.94 F. Porter, D. C. Bardwell, and S. C . Lind, J . Amer. Chem. SOC., 1926, 48, 2603;S. C. Lind and R. S. Livingston, ibid., 1930, 52, 593; S. Gotzky and P. Giinther, 2.physikal. Chem., 1934, 26, B, 373.95 E. F. Ogg, J. Physical Chem., 1939, 43, 399.O 6 H. N. Alyea and S. C . Lind, J . Arner. Chem. SOC., 1930, 52, 1853.9 7 8. C. Lind and C. Rosenblum, Proc. Nut. Acad. Sci., 1932, 18, 374.98 W.M u d , L. Kwrtkemeycr, M. Vanpee, and A. van Tiggelen, Bull. SOC. chim.99 Lind and Bardwell, J . Amer. Chern. SOC., 1926, 48, 2336.Belg., 1940, 49, 187.loo R. Cloetens, Bull. SOC. chim. Belg., 1936, 45, 9722 GENERAL AND PHYSICAL UHEMISTRY.photochemical counterparts which itre chain reactions, and the aimilarityof kinetics suggests the participation of halogen atoms as chain centres.In several cases, detailed analysis of the primary act has shown that thaatoms are formed at this stage, of a kind and number t o enable quantitativeinterpretation of the experimental results.lol7. Single Organic Substances.-Much qualitative work OQ the stabilityof organic oompounds to rays from radium was carried out by A. Kaila,n.loMany of his experimepts were conducted with access to air and with wetmaterials.Nevertheless, the essential features of the radiolysis weradeteoted and have been contirmed by later work. Saturated compoundatend to break at a weak bond and to lose some easily eliminated group.If the remaining fragment is a radical, it may dimerise, and, if it ia &Punsaturated molecule, it will be polymerised. Thus the paraffins aredehydrogenated and the residue consists of liquid hydrocarbans, whethera-particles 99 or high-speed electrons lo2 are used. Similarly, alcohols yieldhydrogen and polymerised aldehydes lo3 amongst the products. Irradiationof chloroform by y- or X-rays causes evolution af chlorine in the initialstages of reaction.lO4 Reabsorption of some of the chloride with formatianof hydrochloric acid and hexachloroethane may occur subsequently.Unsaturated compounds, e.g., olefh~,~O~ cyanogen,lo6 carbonyl Io3 andvinyl compounds 29 polymerise as freely under irradiation as by any atharinitiating action.The polymerisation of acetylene has been very closelystudied because it appeared to be a clear example of it reaction proceedingby the ion-cluster mechanism.107 The evidence for this view as against thenormal radical-type chain polymerisation was principally the apparentconstancy of the ionic yield = 20 over a wide variety of conditions, includ-ing the presence of non-reaetive diluents such as the inert gases or nitrogen.The mechanism, suggested by Lind, was that 19-20 acetylene moleculesclustered about either a C,H,+ ion or an inert-gas ion.On neutralisationthe whole complex was supposed to liberate, as the only product, a solidyellow polymer of formula (C2H2)20. Substantially the same results wereobtained and the same mechanism proposed for dideuteroacetylene, C2D2. lo8The insolubility of the product prevented determination of its molecularIo1 H. Eyring, J. 0. Hirschfelder, and H. S. Taylor, J. Chem. Physics, 1936, 4, 590;loa C. S. Schoepfle and C. H. Fellows, Ind. Eng. Chem., 1931, 23, 1398.lo3 J. C. McLennan and W. L. Patrick, Canadian J . Re., 1931, 5, 470.lo4 W. B. S. Bishop, J . Proc. Sgdney Tech. Coll. %kern. SOC., 1933, 5, 66, quotedlo5 G. B. Heisig, J . Amer. Chem. Soc., 1931, 53, 3245; J . Physical Chem., 1936,lo6 D.C. Bardwell, J. M. Perry, and S. C . Lind, J . Amer. Chem. SOC., 1926, 48, 1556.lo' Ref. 6, G. Glockler and F. W. Martin, Trans. EZectTochem. Sou., 1938, 74, 67;J. C. McLennan, M. W. Perrin, and H. J. C, Ireton, Proc. Roy. SOC., A , 1929,135, 246;W. Mund, C . Velghe, C . Devos, and M. Vanpee, Bull. SOC. chim. Belg., 1939, 48, 269.lo8 S. C. Lind, J. C. Jungers, and C. H. Schifflett, J . Amer. Chem. SOC., 1935, 5'9,1032.1938, 6, 783.in Chem. Abs., 1934,28, 2212; G. Harker, Nature, 1934, 133, 378.39, 1067; 1939, 43, 1207DAlNTON : CBEMICAL REACTIONS 1NDUCED BY IONISING RADIATIONS. 23weight. Recently, it has been shown that the electron micro-photographsof this material are not those expected of a substance C40H40,'09 More-over, this is not the only product of reaction.Benzene is also formed, andunder suitable conditions it may represent as much as 20% of the product.l1°Although these facts render the original cluster hypothesis for this reactionuntenable, they do not necessarily exclude an ionic rnechanism,lll whichappears to be the preferred method when unsaturated hydrocarbons arepo1ymerised.ll28. Binary Organic Mixtures.-Very little systematic work has beenpublished in this field. Direct action has been observed,l13 and indirectaction with an organic compound as solute 114 or s01vent.l~~9. Water and Dilute Aqueous Solutions.-The action of radiations onwater is of great importance, for both its intrinsic interest and its relevanceto the study of the biological action of radiation^.^ All the peculiar featuresof radiochemical reactions, e.g., radiochemical equilibrium, indirect action,influence of track density, etc., are here displayed, Several reviews areavailable.116(i) Experimental results. (a) Ice, Water, and Steam. X-Rays haveno action on ice, unless it contains oxygen, when hydrogeri peroxide isformed. The yield decreases with temperature, becoming zero at - 116°.117On the other hand, a-rays decompose ice even in the absence of oxygen,with an ionic yield of about 0.05 to 0-1 molecule of water destroyed per35 ev. absorbed. This reaction does not appear to be temperature dependent,but, whereas P. Bonet-Maury 117 claims that the product is H,O,, W. Duaneand 0. Scheuer 118 stated that this is exclusively hydrogen and oxygen.Water uapour appears to be even less affected by a-rays, Duane and Scheuerfinding an ionic yield of about 0.01.However, electrons appear to bringabout speedy decomposition. Thus the xenon-sensitised X-radiolysis 119results in formation of much hydrogen in unit yield in amounts strictlyproportional to the dose. Likewise, cathode rays rapidly set up the equi-librium, 2H,O In addition, there is much spectro- H,O, + H,.l2olog J. H. L. Watson, ref. 12, p. 470.l10 C. Rosenblum, ref. 12, p. 474.ll1 W. M. Garrison, J. Chem. Physics, 1947, 15, 78.112 See, e.g., C. E. H. Bawn, " The Chemistry of High Polymers," London,113 E.g., Halogenation of CO- and C,H, : ref. 6 and H. N. Alyea, J. Amer. Chem.114 P. Giinther and H. Theobald, 2.physikal. Chem., 1938, 40, B, 1.116 L. Baumeister and R. Glocker, ibid., 1921, 9'4, 368; E. Broda, Nature, 1943,116 C. 33. Allsopp, Trans. Paraday SOC., 1944, 40, 79; 0. Risse, Ergebn. Physiol.,11' P. Giinther and L. Holzapfel, 2. physikal. Chem., 1939, 44, B, 374; P. Bonet-118 Radium, 1913, 10, 33; Compt. rend., 1913, 156, 466.llV P. Giinther and L. Holzapfel, 2. physikal. Chem., 1939, 48, B, 346.lZo M. Kernbaum, Radium, 1910, 7, 242.1948.SOC., 1930, 52, 2743.151, 448.1930, 30, 242; H. Fricke, Cold Spring Harbor Symp., 1936, 3, 65.Maury and M. Lefort, Nature, 1948, 162, 38124 GENERAL AND PHYSICAL CHEMISTRY.scopical and mass-spectroscopical data on the break up of water by slow-electron bombardment and in discharges.121Many of the thirty-five or so papers which have been published on waterappear to contain contradictory results.The reasons for this are the pro-found effect exerted by dissolved air, the existence of a radiation-sensitisedback reaction, and the inherent instability of one of the reaction products.Despite such diiliculties the following facts have been established. (a) Watercontaining dissolved oxygen is converted into hydrogen peroxide, whatevertype of radiation is used,122 and there is evidence that the amount of H202so formed is proportional to the dose and increases with the concentrationof oxygen present initially and with temperature. (b) The extent of reac-tion is less in ice than in water, and there is thus a discontinuity in theyield a t 0°.1175 118 (c) By use of carefully de-aerated water and massive radi-ation, i.e., a-rays, the products of reaction are hydrogen peroxide andsometimes oxygen, in amounts which together are equivalent to the hydrogenevolved.71, 123 The yield does not appear to depend on temperature butdecreases abruptly on freezing.117 ( d ) When X- or y-rays or fast electronsare the radiation employed, the hydrogen peroxide concentration formed isvery low, and in some cases undetectably (e) Certain compoundswithin a very wide range of chemical substances, when added to water,raise the H202 concentration enormously, without necessarily being affectedthemselves.89~ 125 (f) Hydrogen and hydrogen peroxide are the primaryproducts, and oxygen is formed, not initially, but as the result of somesecondary processes.71Irradiation of solutions containing reduc-ing agents leads to liberation of hydrogen and oxidation of the solute,e.g., Fe++ salts --+ Fef++ salts; 126 nitrites --+ nitrates.127 The presenceof dissolved oxygen increases the rate of oxidation and prevents evolutionof hydrogen; but, as soon as the oxygen is exhausted, the rate falls to thevalue appropriate to de-agrated water and the evolution of hydrogen com-men~es.3~9 128 If the solute is an oxidising agent, e.g., ceric sulphate,potassium dichromate, it is reduced and oxygen is evolved; or, if the soluteis organic, e.g., formic acid, carbon dioxide may be produced.Whenneither oxygen nor hydrogen are detected, it is usually because the solute(b) Dilute Aqueous Solutions.121 For references see Dainton, ref.12, p. 517.lZ2 F. L. Usher, Jahrb. Rad. Elekt., 1911, 8, 323; 0. Risse, 2. physilc’al. Chem.,1929, 140, 133; H. Fricke, J. Chem. Physics, 1934, 2, 556; J. Loiseleur, R. Latarjet,and T. Caillot, Compt. rend., 1941, 213, 730; Bonet-Maury and Lefort, ref. 117.123 C. E. Numbergar, J . Physical Chem., 1937, 41, 431.124 0. Risse ; 122 H. Fricke and F. R. Brownscombe, Physical Review, 1933, 44, 240 ;H. Fricke ; 122 Piffadt, Compt. rend. Soc. B i d , 1939,130,43 ; Giinther and Holzapfel ;Loiseleur et al.; 122 Bonet-Maury; 117 A. 0. Allen.71126 H. Fricke and E. J. Hart, J . Chem. Physics, 1935, 3, 596.lZ6 H. Fricke and S . Morse, Phil. Mag., 1929, 7, 129; H. Fricke and E. J. Hsrt,lZ7 H. Fricke and E.J. Hart, ibid., 1938, 3, 366.lZ8 N. A. Shishakov, Phil. Mag., 1932, 14, 198.J . Chem. Physics, 1935, 3, 60DAINTON : CHEMICAL REAUTIONS INDUUED RY IONISINB RADIATIONS. 25undergoes neither reduction nor oxidation, e.g., it may be polymerised orhydrolysed. The magnitude of the chemical change is often proportionalto the dose and independent of solute concentration over wide 12'For example, this is true of the enzyme carboxy-peptidase, even when it ispresent to the extent of 14% by weight. This constancy of ionic yield isproof that under these conditions the change in the solute is due to therate of energy absorption in the solvent, i.e., that the action is indirect(cf. section 6). However, there is also evidence that a critical concen-tration exists, below which the ionic yield decreases with falling solutecon~entratioii.~~~~ l30 It also seems likely that (a) in the concentrationrange where M / N is constant, different types of radiation may be associatedwith different ionic yields,131 and ( b ) the value of the critical concentrationis determined partly by the nature of the solute and partly by the nature ofthe radiation.Certain solutes, notably large organic molecules of biologicalimportance, subject to indirect action a t concentrations above any real orhypothetical critical value decay exponentially ( i e . , according to a first-order law) throughout a r ~ n . l 3 ~ This suggests the interpretation, nowaccepted, that only that part of the effect of the radiation on the waterwhich is proportional to the percentage of solute remaining is transmittedto the solute.The remainder of the energy is therefore assumed to betransmitted to the soluble product into which the reactant is ~0nverted.l~~When two or more solutes of comparable concentration and reactivity arepresent, there is competition between them; when they are of differentreactivity, the more reactive is transformed preferentially, thereby pro-tecting the less rea~tive.l3~ Pew data are available concerning the effectof temperature 135 and dose rate.37Most of the data summarised above can be inter-preted on a non-cluster mechanism.It was first suggested by 0. Risse in 1929 136that the assumption that X-rays dissociate water into hydrogen atoms andhydroxyl radicals and that these species then dimerise, would account forthe formation of hydrogen peroxide and hydrogen and for the doubling ofthe ionic yield in the X-ray oxidation of ferrous sulphate solution by dis-solved oxygen.I n the same year the capacity of water vapour containinghydrogen atoms and hydroxyl radicals to behave in the dual role of bothan oxidising and a reducing agent was recognised by G. I. Lavin andF. B. Stewart.63 During the following decade the investigations of J. Weiss(ii) -Interpretation.(a) The Primary Act.lz9 H. Fricke, 3.3. J. Hart, and H. P. Smith, J. Chem. Physics, 1938, 6, 228.130 W. Stenstrom and A. Lohmann, J. Biol. Chem., 1928, 79, 673.131 L. H. Gray, W. M. Dale, and W. J. Meredith, private communication.lS2 H.Fricke a d B. W. Peterson, Amer. J. Roentgenol., 1927, 17, 611.133 W. M. Dale, W. J. Meredith, and M. C. K. Tweedie, Nature, 1943, 151, 281.134 W. M. Dale, Biochem. J., 1942, 36, 80.136 T. Alper, Nature, 1948, 162, 616 ; W. Minder and A. Liechti, Ezperientia, 1946,lSe Strahhntherapie, 1929, 34, 6.81.2, 41026 GENERAL AND PEYSICAL CHEMISTRY.and others 137 demonstrated the existence of ready electron-transfer pra-cesses involving hydrogen atoms or hydroxyl radictds in aqueous media,and in 1944 Weiss 13* proposed that the hydrogen atoms and hydroxylradicals present in water subjected to irradiation were formed by loss ofan electron from an OH- into a neighbouring H+ ion, thus : (H0)-H+ +radiation -+ HO + H. He further pointed out that the recombinationreaction, H + OH ---+ H,O, would proceed very easily by the Franck-Rabinowitch mechanism, and that the tendency of the hydrogen atom todonate an electron to, and of the hydroxyl radical to accept an electronfrom, a solute accounted for the oxidising and reducing properties ofirradiated water ; e.g.:Reduction .- He + Ce4+ --+ Ce3+ + H+ ; the excess of OH ultimatelyOxidation : HO- + Fe2+ + Fe3+ + OH-; the excess of H ultimatelyIt is now realised that these simple ideas require considersLble modific-ation, and the picture of the primary act which is in best accord with thedata may be summarised as follows. Transfer of energy from the fastcharged particles to the water molecules which they encounter will producethe following effects.The principal ions so formedare likely to be H20+ (which rapidly reacts to form H+ aq.+ OH withconsiderable energy release), H+ (and the associated OH radical), OH+(and the associated H atom). These will he distributed along the trackwith a concentration proportional to the specific ionisation. Since theradical ion will probably react rapidly with neighbouring water moleculesaccording to HO+ + (H,O), + H+aq. + ZOH, the net instantaneous effectwill be of a column of small cross-section containing predominantly OHradicals with a few H atoms. Some of the hydroxyl radicals may beelectronically excited (,C) and both species may have excess of translationalor internal energy. Such translationally non-average entities will bereferred to as “hot,” because their effective temperatures will be abovenormal. The ejected secondary electrons may have Considerable energywhich will be lost in ionisation and other processes.On the average, suchelectrons will travel considerable distances before their speeds are reducedto a value which permits capture by the only species present in quantitywith appreciable electron affinity, namely, water molecules. H,O- ionswill thus be formed over a much wider area and in lower concentrationthan are the positive ions. This difference in concentration will be themore marked the heavier the ionising partiole, Since H,O- ions break downon hydration, H20- -+- OH- aq. + H, the total effective action of theionisation processes is formation of H + OH in somewhat uneven con-centration, but both entities will occur in increasing concentratios as theend of the track is appr0a~hed.l~~forming H202 via molecular oxygen.forming H,.(1) Ionisation of the water molecules.lS7 See Ann.Reports, 1947, 44, 60. Is@ Nature, 1944, 153, 748DAINTON : CHEMICAL RBACTIQNS INDUCED BY IONISING RADIATIONS. 27( 2 ) Excitation. Both the primary particle and secondary electronsexcite some of the water molecules with which they collide. If 33 ev. isthe total energy required to create an ion-pair, possibly 12-14 ev. may beused in excitation only. Part may be used to excite vibrations in the(‘ micro-icebergs.” The slowness of the degradation of this internal energyto heat is manifested in the (( lag ” in contraction after the radiation sourceis removed from pure water.72 Much of the 12-14 ev.may be employedin direct dissociation of water molecules, Le., H20 + H(W) + OH(2X or ,II).Tho overall effect is thus H2Q --+ H + OH, but it is improbable thatany appreciable amount is formed by direct electron transfer,(b) Secondary Processes. (1) Decomposition of water. Diffusion ofradicals and atoms will occur within the tracks, and also from the tracks.The latter process will lead to intermingling of radicals and atoms origin-ating from different tracks. It is important to know whether such adiffusion pracess follows the normal mechanism in liquids, and thereforewhether the diffusion coefficient can be regarded as of the same order ofmagnitude as that of known molecules of comparable size through water,or whether it occurs by a more rapid process, The possibility of a Grotthuss-type transport of H or OH through a water polymer unit, i.e., HO +H(H,O),OH --+ (H,O),+ + OH, cannot be overlooked.Experiments onthe degree of enrichment of oxygen gas evolved from a dilute solution ofhydrogen peroxide in water which is several-fold enriched in H2180 indicatethat the exchange reaction, H160 + H2180 + H2160 + HlsO, is notunduly fast.139 It would therefore appear that in respect of the OH radical,a t least, diffusion from the tracks occurs by normal processes. Competingwith the diffusion are the ‘( combination ” and (‘ recombination ” reactions.The latter is the reactian, H + OH --+= H,O, and may concern a hydrogenatom and a hydroxyl radical formed from different water molecules situatedsome distance from the point of recombination.It is unlikely to requirean energy of activation and probably occurs a t every collision. On theother hand, the recombining radicals may be derived from the same watermolecule, recombination occurring within the solvent “ cage ” in whichthey were formed.70 Both types of recombination are exothermic and willprovide the means by which much of the energy of the radiation is con-verted into heat. The important difference between the two is that theradicals recombining by the former mechanism will have appreciable separateexistences between formation and destruction and may therefore be regardedas more available for reaction with any solute added or produced.By(‘ combination ” reactions we denote reaction between like species, namely,2H or 20Hy the products of which are H, and H,O,, re~pectively.~~ Suchproducts will accumulate most rapidly where the local concentration of theappropriate radicals is highest and the concentration of the other specieslowest. Thus, H,O, will be formed in the centre of the track and H,over a wider area, both products appearing in larger amounts as the13e E. Collinson and F. 8. Dainton, unpublished28 GENERAL AND PHYSICAL CHEMISTRY.end of the track is approached, and both probably derived from the“ ionisational ” rather than from the “ activational ” hydrogen atomsand hydroxyl radicals, since the latter type is better placed for recom-bination.Furthermore, the lower the energy and the higher the massof the particulate radiation, the more favourable are the conditions forformation of hydrogen peroxide and hydrogen, a result which has beenwell established.71 It has been argued that dipole repulsion forces causereactions between hydroxyl radicals to require an energy of activation,140and some experimental support exists for this.141 The fact that the yieldof hydrogen peroxide in de-&rated water decomposed by a-rays is inde-pendent of temperature 117 shows either that this is not true, or that theradicals are in possession of the necessary energy of activation. Thelatter suggestion is in keeping with the notion that the radicals are “ hot.”71The sharp decrease of ionic yield on freezing could be due to the polymolecularstructure of ice which might increase the temporary “ trapping,” followedby delayed unproductive release, of a greater proportion of energy than inliquid water .The presence of dissolved oxygen enhances the yield of hydrogen per-oxide owing to the fact that some of the hydrogen atoms react readily accord-ing to H + 0, + HO,, the hydroperoxide radical so formed being sub-sequently converted into hydrogen peroxide.This mechanism is respon-sible for most of the yield of hydrogen peroxide in X-irradiated aeratedwater, and, since this yield increases with rise of temperature, one of thesesteps must require appreciable energy of activation. This might be thedismutation, 2H0, -+ H,O, + 0,.As the concentrations of dissolved products build up during an irradi-ation, they will diffuse from the tracks and become increasingly liable toattack by those hydrogen atoms and hydroxyl radicals which have appreci-able lifetimes before recombination.Possible reactions which are known tooccur with great facility at room temperature are (i) OH + H, ---+ H,O + H,(ii) OH + H,O, --+ HO, + H,O, and (iii) H + H,O, --+- H,O + OH ;together with (iv) HO, + H,O, -+ H,O + OH + 0, and (v) H +0, + HO,, these provide for a net back reaction, H, + H,02 + 2H20,which will be a chain process. If a solute is present which reacts withone or both of the radicals with great facility? but which, owing to thevery high local concentration of “ ionisation ” radicals formed with massiveradiation, cannot gain access to these before combination? then, as Allen~uggested,~~ the back reaction will be inhibited and the equilibrium dis-placed towards the products.This author has argued that such a dis-placement effect is to be expected from all solutes, not only from thosewhich react with both radicals, e.g., vinyl compounds and hydrolysablesolutes, but also from those which react with either the H or OH only.The reason is that prolonged irradiation will establish a balance betweenoxidised and reduced forms of the solute, the position of the equilibriumlP0 J. Weias, Tram. Paraday Soc., 1940,30, 866. D. E. Lea, ibid., 1949,45, 81DAINTON : CHEMlUAL RICAOTIONB INDUOED BY IONISING RADIATIONS. 29being determined by the standard redox potential.Thereafter, both Hand OH will be equally destroyed, and the back reaction suppressed. Onthe other hand, if high-energy y-rays are used, very few radicals will beformed in the immediate neighbourhood of similar radicals and a veryreactive solute present in sufficient concentration might destroy practicallyall the radicals, ionisational as well as activational, before combinationoccurred. The forward reaction would then also be suppressed and nohydrogen peroxide or hydrogen be detected. Much more work requiresto be done on this aspect and the more puzzling “gas phase volume ”effect described by Allen.Solutes may undergochemical transformation by one, or a combination, of the following mechan-isms: (i) photochemical change due to absorption by the solute of partof the cerenkov radiation; (ii) excitation of the solute when it deactivatesexcited water polymers ; (iii) reaction with hydrogen peroxide or hydrogen ;and (iv) reaction with hydrogen atoms or hydroxyl radicals formed in theprimary act.These mechanisms are arranged in order of increasing im-portance. Although process (i) must occur, the fraction of the total reactioneffected in this manner is probably very slight. The second mechanismmay be operative, since it is known that even low concentrations of ferroussulphate destroy the ‘‘ lag ” in energy dissipation, but the magnitude of theeffect is The hydroxyl radical and the hydrogen atom may beregarded as very reactive forms of hydrogen peroxide and hydrogen,respectively, and it is therefore surprising that it is necessary to includemechanism (iii) in addition to (iv).The most direct experimental evidenceas to the mode of reaction in any particular system is obtained from studiesof the reactivity of the solute to hydrogen) hydrogen peroxide, hydrogenatoms, and hydroxyl radicals separately in the absence of any ionisingradiation.For this purpose reliable methods of generating hydroxyl radicals andhydrogen atoms in water are required. Hydroxyl radicals can be pro-duced (i) by the action of light of wave-length less than 3700 A. ondilute aqueous solution of hydrogen peroxide, H202 + hv + 20H(2x),(ii) by spontaneous or photochemical electron transfer from a powerfuloxidising ion to a water molecule of its solvation sheath, e.g., CO+++ aq.--+CO*+ aq. + H+ + OH, Fe+++ aq. + hv + Fe++ aq. + H+ + OH,(iii) electron transfer to hydrogen peroxide, e.g., Fe++ aq. + H20, -+Fe+++ aq. + OH- + OH, or (iv) oxidation of a strongly reducing ion bydissolved oxygen, e.g., V++ aq. + 02+ VO+ I- aq. + 20H. Methods whichemploy hydrogen peroxide have the marked advantage that, in the absenceof a solute, the hydroxyl radical initiates a chain decomposition of theperoxide and much oxygen is evolved. Inhibition, by a solute, of thisoxygen evolution is easily detected and can be used as a criterion of reactionof the substrate with the hydroxyl radical. Method (ii) involves cations ofhigh valency, and the presence of strong acid is often necessary to preventhydrolysis. Method (iv) is particularly valuable for effecting polymeria-(2) The chemical nature of indirect action in water.o30 QENBIRAL AND PHYSIUAL GHHMISTRY.ation of water-soluble vinyl compounds, since the oxygen whioh ig normallyan embarrassment owing to its capacity to cause induction periods is, in thiscase, effectively removed in the initiating reaction and can never exert itsretarding action.142In principle, hydrogen atoms could be generated by any prooess leadihgto acceptance of an electron by water.This requires a powerful electrondonor. A uniform concentration of hydrogen atoms might conceivably beachieved by using a highly reducing ion, aqueous solutiona of which spon-taneously evolve hydrogen, e.g., U3+. * Alternatively, photochemical stimul-ation of the electron transfer can be effected, and this method possessesthq advantage that the rate is not markedly temperature-dependent andhigh local concentrations of hydrogen atoms can be produced.Suchadvantages may be offset if the electron-aflnity spectrum of the conjugateoxidising ion falls in the same spectral region or if the solute forms a com-plex with the ion.l*g Moreover, the solutes which may be used are restrictedto those which are either transparent in the appropriate wave-length regionor are unaffected chemically by light in this region.Molecular hydrogen is rarely an effective reducing agent for aqueoussolutes, and most oxidising solutes are therefore considered to react tviththe hydrogen atoms. This may be a simple electron transfer, e.g.,I&+++ aq.+ H + Fe++ aq. + H+ aq,, or addition, e.g., reduction ofoxygen or methylene blue,143 or opening double bonds,27 or a combinationof the two, e.g., S2O8- + H --+ HS0,- + SO4-. It hag been demon-strated that acrylonitrile is polymerised and gas evolution prevented whenaqueous solutions of slightly acidified ferrous sulphate containing this sub-stance are illuminated with ultra-violet light.144 Part of the y- and X-ray-induced polymerisation of this monomer in aqueous solation may thereforebe attributed to the hydrogen atoms. Another chain reaction which isprobably partly initiated by hydrogen atoms is the radiolysis of hydrogehperoxide s01utions.l~~Most reducing solutes which react with hydrogen peroxide will alsoreact with hydroxyl radicals, but the converse does not necessarily hold.Radiochemical reactions in which hydroxyl radicals are presumed to play apart include single-electron-transfer oxidation of reducing ions, e.g.,Fe++ aq.+ OH + Fe+++ aq. + OH- aq., hydrogen-atom extraction,e.g., H,S + 20H __$. 2H20 + S,146 and C,H, aq. + OH -4- H20 +o.5Ph2,147 hydroxylation of aromatic nuclei, e.g., C,H6 _3 C,H,*OH,147and initiation of polymeri~ation.~7 In the la& two examples, the hydroxyl148 D. (3. I;. James and F. S. Dainton, unpublished.143 Colwell, Lancet, 1932, I, 932.144 F. S. Dainton, unpublished; M. G. Evans, private communication,145 H. Fricke, J . Chm. Physics, 1936, 3, 364.laQ J. Loiseleur, Compt. rend., 1942, 215, 536.14' J.Weiss and U. Stein, Nature, 1947, 161, 650.* Added in proof, March 27th, 1049. A wide range of these ions has bow been in-vestigated.142 None appeara to fulfil this r6quirementDAINTON : CHEMICAL REACITIONS INDUGHD BY IONISINQ RADIATIONS. 31group is readily detected in the reaction products. Most of these reactionswould be expected to require little energy of activation; and in keepingwith this it is found that temperature has no effect on the rate of oxidationof ferrous sulphate solutions by X- and y - r a y ~ , ~ ~ ~Solutes which are of biological importance present certain interestingohemical features. The chemical changes undergone are often not under-stood, but are associated with a drastic alteration of biological activitywhich is made the basis of assay.The methods available for identifyingthe active agent are thus reduced. Two examples must suffice. Theenzyme ribonuclease is inactivated by X-rays in dilute aqueous solution.Protection against such inactivation may be achieved by addition of organicreducing agents, e.g., thiol-containing compounds, an observation whichsuggests that hydroxyl radicals or hydrogen peroxide rather than hydrogenatoms or molecules are responsible. The enzyme is, however, fairly stableto O.O~N-H,O,, and it is concluded that hydroxyl radicals must cause theinactivation. E. Collinson, P. 8. Dainton, and (Mrs.) B. Holmes 14* haveconfirmed this directly by demonstrating that ribonuclease is inactivated,and inhibits the evolution of oxygen, when dilute hydrogen peroxide isilluminated by ultra-violet light.By contrast with this behaviour T. A l ~ e r l ~ ~has shown that hydrogen peroxide and not the hydroxyl radical is the activeagent in the X-ray inactivation of bacteriophage S.13, since (a) hydrogenperoxide is detected, (b) phage is inactivated by hydrogen peroxide, (c) theamount inactivated, plotted against time, shows a lag to be expected of aseries of consecutive steps, and (d) the reaction has a considerable tem-perature coefficient.Several independent attempts havebeen made which agree in general outlook, but differ in detail, to predictthe dependence of ionic yield on such variables as concentration, specificionisation, e t ~ . ~ * ~ All these treatments omit any consideration of the backreaction, an omission which is of less importance when solutes are presentwhich react easily with both hydrogen atoms and hydroxyl radicals.Thefollowing over-simplified treatment enables the important features to beemphasised. Let I be the dose rate (ev./W absorbed per unit volume perunit time), and 1%/2 be the net number of water molecules dissociated perWev. absorbed after allowance has been made for the almost instantaneousrecombination of radicals by the Franck-Rabinowitch mechanism. Denotethe concentration of any solutes by sI, slI, etc., and let kl’, kl”, etc., be therate constants for removal of the radicals by the appropriate solutes. Thus(3) The kinetics of indirect action.dnldt = 0.5kI - X k l t ~ ’ f i - (1%3 + E,)n2 .. . . . (2)where n represents the concentration of radicals, and is initially non-uniformthroughout the system, Tc, is the velocity constant for recombination ofunlike radicals which have been formed from different molecules, and k,D. E. Lea, ref. 4, Chapter 11; Weiss, Trans. Faraday Xoc., 1947, 43, 314;Dainton and N, Miller, X?th Indstw&. CoszgTeda, 1947 ; F. S , Dninton.’814* Unpublished32 GENERAL AND PHYSWAL CHEMISTRY.is the velocity constant for combination of like radicals in pairs to formhydrogen or hydrogen peroxide. Actually, the extent of mutual interactionof the radicals (the last term) will depend upon the specific ionisation of thetracks, the distribution of hydrogen atoms and hydroxyl radicals within thetracks, and their diffusion constants.The alternative , more quantitativeapproach * is concerned much more with the fractional number of radicalswhich have recombined at any instant in a track of given specific ionisation.If pl', p(', etc., are the probabilities that in the radical-solute collisionthe solute is destroyed, the rate of reaction = - Zds'/dt = Xpl'El's'n,When only a single solute is and the ionic yield M / N =present, two extreme cases are possible :Cpl'kl's' . n . I(a) E1'd > (k3 + E,)n, whence M / N = p1'k/2(b) El's' < (k3 + E,)n, whence MIN = pl'k,'s'[k/21(k3 + E4]*Thus a t high concentrations the ionic yield is independent of solute con-centration and dose rate, whereas at low concentrations the ionic yielddecreases with decreasing solute concentration and increasing dose rate.The value of s' a t which the dependence of ionic yield on s' commenceswill be determined by the relative values of El', and (k3 + E4).Very reactivesolutes will show type-(a) behaviour to lower concentrations than do lessreactive solutes, and use of "heavy " radiations which give large specificionisations will lead to change from type (a) to type (b) at higher concen-trations than " light " radiation. Several experiments have been reportedfor which the dependence of ionic yield on s' and type of radiation can beexplained in this way,73' l31 and N. Miller 37 has shown that change of doserate has no effect on M / N in region (a) for the oxidation of ferrous sulphatesolution.When the product of the reaction removes the radicals as efficientlyas the reactant, it is easily shown that, if no combination of radicals isoccurring [type (a)], then s = s0exp.( --- I t ) . Such exponentialdecrease of solute concentration with dose (It) has often been 0b~erved.l~~Protection of one solute sI by a second (&I) is easily seen from equa-tion (2), since the ionic yield with respect to sI is given byApplication of this equation enables the relative protection efficiencies ofvarious agents with reference to a given substrate to be assessed.lSThe above discussion relates to solutes which react with hydrogenatoms or hydroxyl radicals. For those rare cases in which the solute maybe inert thereto but reactive to hydrogen peroxide, we have three simul-taneous equations :290(MIN)' = pl'kE,'~/2(kl's' + kl"~'')dn/dt = 0.57~1 - (b + k4)n2d(H,O,)/dt = kpn2 - X:k,'(H202)s'- dd/dt = pl'kG'S'(HaOaHARTLEY : AQUEOUS SOLUTIONS OF SOAP-LIEE SUBSTANCES.33There will therefore be a lag phase before the hydrogen peroxide concen-tration reaches a stationary value, when the rate will be given byds’ - p,‘k,’s‘E,kIdtUnder appropriate conditions, protective action and exponential dependenceon dose would be observed, but in no case would the steady state ionic yielddepend on dose rate. The velocity constant k, refers to reaction betweenthe solute and hydrogen peroxide and is likely to have a much larger energyof activation than any rate constant hitherto mentioned. Greater tem-perature dependence is therefore to be expected for reaction via hydrogenperoxide than via hydrogen atoms or hydroxyl radi~a1s.l~~- - _2(k3 + k4) .Ck5”’1 am grateful to Messrs. E. Collinson and Y. Smith for unstinted helpin searching the literature.F. 8. D.2. STRUCTURE OF AQUEOUS SOLUTIONS OF SOAP-LIKE SUBSTANCES.A soap is an alkali-metal salt of a straight-chain fatty acid or mixtureof fatty acids having upwards of about 10 carbon atoms. On grounds ofrelative hvailability from natural sources and solubility in the desiredtemperature range, the most frequent mean numbers of carbon atoms are12, 16, and 18 in the saturated series and 18 (oleic acid is the cis-form) inthe series with one double bond in the chain.Numerous compounds of similar physical properties have becomeindustrially available in recent years, differing in the nature of the ionicgroup. Many of these have been the subject of extensive academic investig-ations, and, where the ionic group has been derived from a strong acid orbase and is not bulky or coinplex in structure, these compounds are similarin their behaviour and.better suited to exact enquiry, the complicationsintroduced by the hydrolysis of the salts of the weak carboxylic acids beingavoided.These compounds, too, have been placed by same authors under thegeneric title of “ soaps ”, while in other quarters and largely influenced bytrade policy, the extension of this title beyond its original meaning hasbeen vigorously opposed. The general title “ paraffin-chain salts ” proposedby the Reporter has been very widely used, but suffers from a potentiallyexcessive generality which is becoming increasingly important.With thedevelopment of synthetic compounds in this field, particularly products ofthe petroleum industry, the simple pattern of an unbranched aliphaticchain with a simple terminal ionic group is frequently discarded, sometimesthrough accident of easier synthesis, more often deliberately in order toobtain certain desirable physical properties. Compounds with more thanone chain, or branched chains, or containing mixed aliphatic and aromaticelements form solutions of markedly different structure.REP.-VOL. XLV. 34 GENERAL AND PHYSIUAL CHEMIBTRY.We shell therefore distinguish in this Report between normal parafin-chain salts, including soaps, where the parafin chain is unbranched andthe ionic group terminal (Le., normal in the sense in which normal primaryamyl alcohol is distinguished from secondary and iso-alcohols) , and complexparaffin-chain salts of various types.The deviation from the simple typeis, of course, frequently so small as to leave the most important physicalproperties largely unaltered.The industrial development of these compounds as emulsifying, wetting,and suspending agents has sought amongst other objects that of avoidingthe limitations of the true soaps due to the very low solubility of theircalcium and magnesium salts. This is not simply avoided by replacementof the carboxylic by the sulphonic group, as is sometimes loosely stated,since many of the sulphonates form equally insoluble salts with thesemetals.It is unfortunate that the alkaline-earth metals are the mostintractable in this respect. Soluble paraffin-chain salts of zinc, copper,and even iron are more numerous (even the fatty acids have solublecuprammonium salts).More generally resistant to hard water are the " reversed " salts, Le.,those with a surface-active cation. These do not appear to have a corre-sponding tendency to form insoluble salts with bivalent anions. Mostresistant of all are the numerous compounds where the ionic group hasbeen replaced by a non-ionic water-attractive group such as lightly poly-merised glycerol or ethylene oxide. These neutral amphipathic agents havenow a very considerable field of technical application. They have, how-ever, been the least studied of the whole group by academic research workers,mainly on account of the great difficulty of obtaining them in a pure state.Academic work on this group of compounds is still primarily concernedwith the nature of their aqueous solutions, and in this report we shall dealwith this subject almost exclusively.It is desirable to note, however,that some of the most important technical applications of the compoundshave very little relation to the more peculiar features of solution structuresince these appear in concentrations well above the range of most technicalinterest. It is a matter of regret that academic research has seemed hereunduly slow to discover a field of a t least equal intellectual interest andmore technical importance.One may note also that few of the morecomplex types of salt have found their way into academic literature. Wherethey have done so, technical preparations have most often been used andtoo little help seems to have been given by the preparative chemist to hisphysical colleague-a state of affairs which could be remedied by morepreparative activity on the part of the latter.andagain in 1940.2 The Reporter published a summarising article dealing withhis own theory of the structure of aqueous solutions of the normal saltsin 1939.3 I n this article we shall therefore consider fully only the workThe present subject came under review in these Reports in 10361 N.K. Adam, Ann. Reports, 1936, 33, 103.8 A. S. C. Lawrence, im., 1940, 87, 90. G. S . Hartby, K o l M - Z . , 1930, 88, 22HAR-TLEY : AQUEOUS SOLUTIONS OF SOAP-LIKE SUBSTANCES. 35which ha& appeared since these dates, except where reference to specificearlier papers is necessary for an understanding of the more recent develop-ments. There have been developments along three main branches of thesubject : (1) examination, mainly by already established methods, of themore complex salts, (2) study of the solvent power of aqueous solutions,and (3) application of X-ray diffraction technique to the problem.1. The Behaviour of the More Complex Salts.It was inevitable that the development of synthetic imitations of soapwould lead to that of amphipathic substances of more complex type which,while retaining the essential combination of a non-polar part of the moleculewith a strongly water-attracting part, altered substantially the geometricaldistribution.Leaving aside the mixed aryl alkyl salts developed technicallyas wetting agents and the complicated and impure sulphation products ofunsaturated glycerides (e.g., Turkey-red oil), the earliest reference to workon compounds of defined structure differing essentially geometrically fromthe normal paraffin-chain salts appears to be one * in which salts withbranched paraffin chains were noted to have remarkable powers of killingacid-fast bacteria. Unfortunately, in this work numerous salts and acidswere compared under conditions of undefined differences of physical form,some being undoubtedly in solution and others equally certainly existingas suspensions of more or less crystalline solids.Reference to aliphatic compounds where the chain is branched fromthe carbon atom adjacent to the ionic group was first made in the patentliterature in describing the compounds now known as Tergitols, the emulsi-fying properties of which were later described in the technical literature.6These are sulphates of secondary alcohols where the ionic group is nearerthe middle than the end of the chain and where the chain itself may bebranched.Later,' the Aerosols were announced. These are sulphonatesof dialkyl esters of succinic acid, the sulphur being attached to one of themiddle carbon atoms of the acid.Here, too, the ionic group is near themiddle of the chain, but, since the ester groups also will contribute insmaller measure to the water attraction, they are perhaps better regardedas compounds where two chains of moderate length are attached to oneionic head in place of the traditional single long chain of the soaps andearlier synthetic detergents. A convenient series of compounds of thistype was made by the Reporter by sulphonation of various dialkyl ethersof dihydric phenols.It was expected that these compounds would be able less easily to formthe normal type of dilute solution micelle than compounds containing thesame number of aliphatic carbon atoms in a single chain. The ReporterW. M. Stanley, G. H. Colman, C. M. Greer, J. Sacks, and R.Adams, J . Pharm.Exp. Ther., 1932, 45, 121.ti B.P. 440,539.B. G. Wilkes and J. N. Wickert, I d . Eng. Chem., 1937, 29, 1234.B.P. 446,668. G. S. Haxtley, J., 1939, 182836 GENERAL AND PHYSICAL UHEMISTRY.has advanced in a number of papers9 the view that the micelles whichform in dilute solutions of the normal paraffin-chain salts are essentiallyliquid and approximately spherical, their radius being determined by thedepth to which the end of a paraffin chain can reach when its ionic endgroup is anchored approximately in the surface. Replacement of one longby two short chains must reduce the maximum radius of this type of micelleand therefore very greatly reduce the number of ions in each micelle. Asa result, the surface of the micelle will be much less completely hydrophilic,and surface energy considerations would lead us to the conclusion thatthe micelle will be much less readily formed.On the other hand, an ion with two short chains will not be adsorbedon a macroscopic oil surface in water with much less energy advantagethan an ion with a single chain of the same total length.At a concen-tration where no aggregates exist in either solution we might expect thesingle-chain salt to be more surface active than the double-chain salt. Athigher concentrations, however, where micelles have formed in the aqueoussolution of the single-chain salt, the concentration of separate ions will bemuch higher in the double-chain salts. The surface activity of the latterwill therefore become greater, In a study of the interfacial tensions betweencarbon tetrachloride and cycbhexane and solutions of various compoundsof the ether series above rnentioned,lO it was indeed found that the double-chain salts, while less active than a single-chain salt in very dilute solutions,cause the interfacial tensions to fall much lower in higher concentrations.At a concentration of 0.08% the monosulphonate of the dioctyl ether ofresorcinol was found to have an interfacial tension against a mixture ofthe above non-polar liquids of only 0.04 dyne/cm.Only experimentaldifficulties of measurement prevented lower interfacial tensions beingrecorded. Normal paraffin-chain salts do not reduce interfacial tension toless than 1 dynelcm. in any concentration.It was noted in the above work that these salts are not so effectivewith aromatic oils, and a drift of interfacial tension with time was evidentowing presumably to slow transfer of salt to the oil phase.These salts areall much more soluble in organic liquids than comparable normal salts.Copper and nickel salts of Aerosol O.T., for example (O.T. is the sulphonateof the dioctyl ester of succinic acid), are obtained by evaporation as clearglasses which are indefinitely soluble in most organic liquids.11 Thepotassium salt of 1 : 3-dioctyloxybenzene-4-sulphonic acid is freely solublein benzene and chloroform, moderately in petrol, but almost insoluble indry acetone. That of 1 : 4-dioctyloxybenzene-3-sulphonic acid is verysoluble in all solvents with the exception of paraffins a t one extreme andwater a t the other.8’ 11 It is to be expected that these salts would, ongeometrical grounds, form less stable crystals and so be universally moresoluble, but this does not seem a fully satisfactory explanation.Onemight also expect a greater facility in the formation in organic solvents* Summarised in ref. 3.l1 I&m, unpublished observations.l o G. S. Hartley, Trum. Pura&ay SOC., 1941, 37, 130HARTLEP : AQUEOUS SOLUTIONS OF SOAP-LIKE SUBSTANCES. 37of the reversed type of micelle, considered to be present in solutions ofalkali and alkali-earth soaps in non-polar oils. This would lead to theexpectation of greater solubility in paraffis than in more polar solvents,which is not found to be general.More work on these almost absurdsolubilities would be desirable.It is well known that the soaps give rise successively to three new liquidphases as the concentration is increased.12 No phase-rule studies on theinore complex salts seem to have been made, but it is evident to anyonewho has worked with these substances that here too new phases can ariseand in much lower total concentrations. At ordinary temperatures thesulphonates of near-symmetrical dialkyl ethers of resorcinol have a limitedrange of concentration in which clear homogeneous solutions are obtained.Above this concentration a very fine emulsion is formed which can becoagulated by siniple salts to give a macroscopic second liquid phase. TheReporter has noted that crystals of potassium 1 : 3-dioctyloxybenzene-4-sulphonate, formed by slow evaporation of an aqueous glycerol solution,disperse spontaneously to the emulsion form if transferred to water.The crystals mentioned above are massive rhombohedra, obviously offundamentally different structure from the very thin plates formed by thenormal salts.Yet another unexpected property of these double-chainsalts is their ability to form stable thin films in aqueous and glycerol solu-tions. These surpass in length of life the standard ammonium oleatesolution,s but have evidently lower viscosity as they thin down by drainagethrough the coloured interference bands to the very thin black film muchmore rapidly than do soap solutions and remain almost indefinitely in theblack state when protected from evaporation and dust.P. A. Winsor lRhas observed that this thinning gives a characteristic ghost-like appearanceto a " head " of froth in these solutions (he worked with near-symmetricalsecondary sulphate esters) and that the normal salts are antagonistic tothis type of film. Addition of a small concentration of a normal salt pro-duces a solution with very transient frothing power. Further additionreplaces the stable ghost froth by a stable opaque froth similar to thatformed by soap solutions.A. W. Ralston and his collaborators l4 have applied the establishedconductivity technique to study the aggregation of solutions of these double-chain salts. They examined a series of dimethyldialkylammonium salts.They found here, too, the rather abrupt fall of equivalent conductivity a ta critical concentration, known to indicate the sudden formation of aggregatesin the normal salts.The fall was, however, not so great and the criticalconcentration not so low as in a solution of a normal salt with the samel2 See, e.g., J. W. McBain and M. C. Field, J . Physical Chem., 1926, 30, 1545;J. W. McBain, L. H. Lazarus, and A. V. Pitter, 2. physikal. ClLem., 1930, A , 147, 87;J. W. McBain and E. Gonick, 3. Amer. Chem SOC., 1946, 68, 683.l 3 Nature, 1946, 157, 660.l4 A. W. Ralston, D. N. Eggenberger, and P. L. du Brow, J . Arner. Chenz. Xoc.,1948, 70, 97738 GENERAL AND PHYSICIAL CHEMISTRY.number of aliphatic carbon atoms. For example, the critical concentrationsfor C8C,CC and C,oCloCC compounds are about 0 .0 3 ~ and 0.0025~ ascompared with interpolated values of about 0.002~ and 0.0004~ for theisomeric Cl,CCC and C,,CCC compounds. It is noteworthy that the dis-crepancy is much greater between the salts of lower molecular weight.No great difference was found between the C,C12CC and CloCloCC compounds.Extensive solubility work recently published by P. A. Winsor, whichwill be referred to in other connections below, includes measurements ofthe critical concentration l5 in a series of sodium sulphates of n-tetradecane,differing in the position of the carbon atom to which the sulphate groupis attached. The indicator method of M. L. Corrin, H. B. Klevens, andW. D. Harkins l6 was employed. It was found that the critical concen-tration rose throughout the series from that of the normal compound,1.7 x lOP3~, to that of the most symmetrical (7-sulphate), 16 x l O V 3 ~ .Consistently with H.V. Tartar’s observations, however, the relative changefor a displacement of one carbon atom is least when the compound is nearsymmetrical.J. W. McBain l7 and his collaborators have measured the freezing pointsin low concentrations of aqueous solutions of some of the double- andbranched-chain salts. They find a less abrupt fall of osmotic coefficienta t a less well-defined critical concentration than in normal salts, that forAerosol O.T., O - O O ~ N , being some ten times greater than for a normal saltwith 18 aliphatic carbon atoms. For Aerosol I.B. (diisobutyl) the criticalconcentration is about 0 .3 ~ . The ratio is consistent with the findings ofA. W. Ralston and his collaborators l4 for the dimethyldialkylamines.H. V. Tartar and his collaborators have reported some very preciseconductivity data on aqueous solutions cf alkylbenzenesulphonates l8 andalkyltrimethylammonium bromides l9 over a range of temperatures. Theextreme sharpness of the break in the curves relating equivalent conductivityto the square root of the concentration is very clearly demonstrated in thiswork. In the sulphonates the sulphonic group was para to the alkyl and,in this arrangement, it was concluded that the benzene ring was the equiv-alent of one and a half aliphatic carbon atoms in its effect on the criticalconcentration.From the same laboratory was published an interestingstudy 2o of conductivity in another type of double-chain salt, where bothcation and anion have one short paraffin chain, in this case trimethyloctyl-ammonium octylsulphonate. The critical concentration was much lowerand the fall much greater than in the case where one ion is simple.Another development in conductivity studies may conveniently bereported here. E. C. Evers and C. A. Kraus 21 noted that octadecylpyrid-l7 J. W. McBain and 0. E. A. Bolman, J . PhysicaE Chem., 1943,47,94; J. W. McBainand A. P. Brady, J. Amer. Chem. SOC., 1943, 65, 2072.l 8 A. B. Scott and H. V. Tartar, ibid.Jp. 692.2o A. B. Scott, H. V. Tartar, and E. C. Lingafelter, ibid., p. 698.21 Ibid., 1948, 70, 3049.Trans.B’araday SOC., 1948, 44, 467. l6 J . Chem. Physics, 1946, 14, 480.R. G. Paquette, E. C. Lingafelter, and H. V. Tartar, ibid., p. 686HARTLEY : AQUEOUS SOLUTIONS OF SOAP-LIKE SUBSTANCES. 39inium iodate behaves unusually in that the equivalent conductivity fistrises abruptly over a short range with increase of concentration above thecritical, before going through a maximum and then falling steeply in thenormal manner. The nitrate and bromide showed normal behaviourthroughout. One may note that the mobility of the paraffin-chain ionconstituent always rises a t the critical concentration,22 as would be expectedfrom the reduced resistance of the combined ions. The fall of total con-ductivity is due to the predominant effect of the secondary association ofions of opposite sign when the charge density is increased by the primaryaggregation.Could homo-ionic aggregation occur in an infinitely dilutesolution, a rise of total equivalent conductivity would always be expected.The more dilute the solution in which primary aggregation can occur andthe smaller the conductivity of the counter icns, the more likely is thisphenomenon to occur. It is not therefore surprising that it is not evidentuntil a t least 18 carbon atoms are introduced into the single chain andthen only with less mobile counter ions. A conductivity rising with aggreg-ation was, of course, first foretold by J. W. McBain, although, in thecase of very much higher concentrations where a rising conductivity wasfirst found, we now know that the explanation must be sought on differentlines.23 It was first found experimentally by C.Robinson and H. E. Garrett 24in the case of certain dyes. At high field strengths the same type of curvewas found 25 in cetylpyridinium chloride, the effect of secondary aggregationbeing reduced a t high relative velocities of the ions.In a later paper, P. F. Grieger and C. A. Kraus26 first confirm earlierresults of A. F. H. Ward 27 that addition of lower alcohols blyrs the criticalphenomenon and, in sufficient concentration, eliminates it, but they findadditionally that, with some salts, the presence of 10-35% of methylalcohol in the aqueous solvent calls into being, a t the critical concentration,a transient rise of equivalent conductivity, which is not evident in wateralone. This is found with octadecylpyridinium chloride, bromate, andformate but not with bromide, nitrate, and oxalate.This peculiar behaviourremains obscure.The transient rise of equivalent conductivity a t the critical concen-tration in water alone and in normal field strengths was also found byA. W. Ralston et aZ.15 in the double-chain quaternary salts when two12-carbon-atom chains were present. In this cam we have altogether 26a-liphatic carbon atoms, probably a higher number than in any compoundpreviously known to be soluble a t ordinary temperatures. The criticalconcentration is about ~ O * N and the micelle will presumably contain fewerions than a normal salt aggregating a t this concentration, so that the con-ditions are very favourable to an abnormally small effect of secondaryionic association.22 C.S. Samis and G. S. Hartley, Trans. Paraday SOC., 1938,34, 1288.23 Ref. 3, p. 36.25 J. Malsch and G. S. Httrtley, 2. physikal. Chern., 1934, A , 170, 321.28 J . Amer, Chem. SOC., 1948, 70, 3803.24 Tram. Paraday SOC., 1939, 35, 771.27 Proc. Roy. SOC., 1940, A , 51240 GENERAL AND PHYSICAL CHEMISTRY.Solubility measurements in solutions of more complex salts will bereported in the next section.2. Solubility Phenomena.Many organic substances of limited solubility in water are renderedcompletely miscible by addition of paraffin-chain salts. Others, of verylow solubility in water, are much more soluble in solutions of paraffin-chain salts.This phenomenon is concerned with a reversible, equilibriumprocess and is quite distinct from that of emulsification. Benzene, forexample, can be added slowly to a 10% solution of cetylpyridiniuni chloridein water and is taken up entirely therein to give an optically empty solution,provided the benzene concentration does not exceed about 7 yo, dependingon temperature. Further added benzene forms a visible emulsion con-taining droplets of varying size where average size depends on the historyof the mixture. Several careful researches 28 have established the reversibleequilibrium in the true solutions. For hexane in sodium oleate solution,J. W. McBain and J. J . O’Connor 29 have measured the equilibrium vapourpressure in solutions below saturation and find a normal type of pressure-composition curve.There has been a general usage of a new word to describe this phenomenon,namely, “ solubilisation ”.The Reporter considers that this is unneces-sarily confusing. It appears to imply that an essentially new process isunder investigation and it is often held, in consequence, that the resultingsolutions are not in equilibrium. We are not dealing with an entirely newprocess when we dissolve benzene in an aqueous paraffin-chain salt solution.The peculiarity is that the solvent is unusual in structure rather than t.hatthe solute is brought into an unusual state. Phenomenologically, thedifference between a system where alcohol or acetone is the co-solvent andone where a paraffin-chain salt is the co-solvent is quantitative only.A much smaller amount of a paraffin-chain salt than of acetone isnecessary to bring amyl alcohol and water into complete miscibility.Amuch larger amount of naphthalene is dissolved by a given concentrationof paraffin-chain salt in water than by the same concentration of acetonein water. There is, associated with this difference, an even more dis-tinctive one, but still essentially quantitative. A rapidly increasing addi-tional amount of naphthalene is brought into solution by each successiveequal increment of acetone. With paraffin-chain salts, over a considerablerange of concentration, the additional concentration of saturant is pro-portional to the additional concentration of co-solvent. The solvent powerof the paraffin-chain salt, unlike that of the acetone, is not appreciablylost by dilution with water.Below the concentration known from othermeasurements to be the critical one for formation of micelles, the solventpower is, however, very rapidly lost.2 8 R. S. Steams, H. Oppenheimer, E. Simon, and W. D. Harkins, J . Chem. Physics,1947, 15, 496; J. TV. McBsin and A. A. Green, J. Amer. Chem. SOC., 1946, 68, 1731.Ibid., 1940, 62, 2855HARTLEY : AQUEOUS SOLUTIONS OF SOAP-LIKE SUBSTANCES. 41The fundamental explanation of this difference is now generally agreedby all workers in this field. The unusually high solvent power of theparaffin-chain salts, but little affected by dilution, is due to the salt beingpresent in the form of relatively large aggregates.Amicroscopically, theco-solvent is not diluted by the water and thus retains its solvent power.The solvent power of ordinary co-solvents is also due to aggregates, butthese are relatively smaller and therefore less effective and widely dis-tributed in size and therefore the mean size is much dependent on con-centration. The less ideally miscible with water is the co-solvent, the lesscompletely does it lose its solvent power, as is well illustrated in the datafor naphthalene and the three lowest alcohols obtained by J. Christiansen 30and previously commented on in the present connection by the Reporter.31It is noteworthy that there are observations, somewhat neglected inthis connection, of the solubility of several organic substances of low watersolubility in solutions of simpler organic electrolytes, such as sodiumbenzoate and ~alicylate.~~ The normal salting-out effect of the electrolyteis reversed a t quite low concentrations and in high concentrations the‘( organic ” effect predominates.There is, of course, no sharply definedcritical concentration, and the solvent power, presumably due to smallclusters as in solutions of alcohol in water, is great only in concentratedsolutions.The Reporter31 found that the solubility of azobenzene in aqueoussolutions of cetylpyridinium chloride is approximately the same as in anequivalent amount of hexadecane. His argument that the micelle is there-fore essentially liquid in its paraffinic interior has received adverse comment 33when taken out of its context.Simple paraffinic solvent properties areonly to be expected and are only found when the solute is non-polar. Polar,and especially amphipathic, molecules are likely to be oriented in thesurface of the aggregate. Since the diameter of the latter is only of moleculardimensions, it is to be expected that orientation will have a very greateffect on solubility. Many simple dyes are much more soluble33 inparaffin-chain salt solutions than would be expected on simple addition ofthe water and paraffin solvents. J. W. McBain and H. McHan34 haveshown that dimethyl phthalate, which has practically zero solubility inwater and a low solubility in higher paraffins, is much more soluble inparaffin-chain salt micelles.Recently, W.D. Harkins and H. Oppenheimer 35 have proposed a dis-tinction between ‘( solubilisation ” when the solute is dissolved in theinterior of the micelle and “ penetration ” when it is oriented in its structure.30 Medd. K . Vetenskapsakad. Nobel-Inst., 1918, 4, No. 2.31 G. S. Hartley, J., 1938, 1968.32 J. Traube, I. Schoning, and L. J. Weber, Ber., 1927, 60, 1808; E. Lersson, 2.physikal. Chent., 1930, A , 148, 304; 1931, A , 153, 299, 466; H. Freundlich andG. V. Slottman, Biochem. Z., 1927, 188, 101.3s J. W. McBain, article on “ Solubilisation ” in Advances in Colloid Science (Inter-science, 1942), Vol. 1,34 J . Amer. Chem. Soc., 1948, 70, 3838. J . Chem. Physics, 1948, 16, 100042 UENERAL AND PHYSICAL CHEMISTRY.There can bs no doubt that molecules themselves amphipathic will beincorporated in the micelle with similar orientation.A. F. H. Wardz7considers that the lower alcohols are held predominantly in the micellesurface. E. Angelescu and T. Manolescu 36 consider phenols t o be similarlydisposed or even oriented outside the micelles.I. M. Kolthoff and W. F. Johnson 37 have made use of the solvent powerof micelles for dimethylaminoazobenzene to determine the critical concen-trations in several soaps. They found the critical concentration veryindefinite with rosinate. J. W. McBain, R. C. Merrill, and J. R. Vino-grad 38 find that the solubility of phenylazo-9-naphthylamine in soapsolutions is considerably less than in solutions of salts of paraffin-chaincations and of many more complex salts.R. C. Merril133 finds a lessmarked disadvantage of the soaps as solvents for o-tolylazo- @naphthol,and A. M. Soldate’s results33 put potassium oleate as much less effectivethan Aerosol O.T. as a solvent for propylene vapour.I n the studies just referred to, Turkey-red oil, which is, of course, largelysulphated unhydrolysed glycerides, stands out as having solvent powerfor the dyes examined comparable with that of the higher alkyl quaternaryammonium salts. The bile salts have no very outstanding solvent powerin solution, the extraordinary adsorption properties of deoxycholic acid inthe solid state evidently being due to an abnormal crystal structure. I nsolutions of Aerosol O.T. and sodium deoxycholate the critical transitionfrom the ultimately dissolved state to the aggregated state is shown bythe solubility measurements to be less abrupt than with normal paraffin-chain salts, consistently with the other evidence quoted above on theformer compound and related dialkyl salts.The phenomenon of indicator equilibrium displacement, noted in 1934 39and later applied to quantitative titration of paraffin-chain cations byparaffin-chain anions 40 and to investigation of the ratio of surface to bulkpH,4l has been the subject of further research and experimental refinement.It is, of course, an example of the “ solubilisation ” phenomenon.M. L.Corrin and W. D. Harkins 42 have found indicators particularly suitable tothe determination of the critical concentration without interference with it.Other less direct applications of solvent power have been made in analyticalprocedure.43 The influence of the solvent properties of the paraffin-chainsalt micelle on the bactericidal effect of dissolved phenols has been thesubject of a recent research.44Phenols and alcohols of medium molecular weight have long been used36 Kolloid-Z., 1941, 94, 319.38 J.Amer. Chem., 1941, 63, 670.39 G. S. Hartley, Trans. Faraday Xoc., 1934, 30, 444.40 G. S. Hartley and D. F. Runnicles, Proc. Roy. SOC., 1938, A , 168, 420.41 C. S. Hartley and J. W. Roe, Tram. Farday Xoc., 1940, 36, 101.42 J . Amer. Chem. SOC., 1947, 69, 679.4a T. U. Marron and J. Schifferli, I d . Eng. Chem. Anal., 1946, 18, 49.44 A. E. Alexander and A. J. H. Tomlinson, Faraday Society Discussion, “Reoent37 J.Physical Chem., 1946, 50, 440.Advances in Surface Chemistry ” (in the press)HARTLEY : AQUEOUS SOLUTIONS OF SOAP-LIKE SUBSTANCES. 43technically in the formulation of special soap solutions and studies of soap-water-phenol systems were among the first made in this field.45 Renewedinterest has recently been taken in similar systems. J. H. Schulman andT. S. McRoberts 46 have examined the consolution of water and benzene orparaffin by sodium oleate in the presence of various alcohols, by titratingmixtures to the end-point of fluid transparency. Accepting a t that timethe lamellar view of the micelle in aqueous solutions, they consider thatthe penetration into it of the oil phase first liquefies it and that the swollenmicelle is then capable of growth to spherical droplets of the order of 200 A.diameter.Whether an oil-continuous or water-continuous system resultsthey explain in terms of the relative wettability by water or oil of theinterfacial layer consisting of alcohol and soap molecules. Distinctionbetween these two types of system is made experimentally by conductivityobservations. They find that, over certain ranges of composition, thesystems are, with regard to this inversion, extremely sensitive to themolecular size of the alcohol and the nature of the hydrocarbon.R. C. Pink*' has examined the equilibrium adsorption of water vapourby benzene solutions of ethanolamine oleate and finds that the adsorptionincreases very rapidly with further rise of temperature above about 45".This he attributes to a fusion of 8 previously crystalline aggregate-in thiscase, of course, of the " reversed " structure, with the paraffin tails arrangedexteriorily .A very extensive study has been made by P.A. Winsor of oil, alcoholor amine, water, paraffin-chain salt systems. Various types of system canbe reslised,48 isotropic solutions from oil-continuous to water-continuous,such solutions in equilibrium with excess oil or water, and anisotropic gelsystems a t intermediate compositions between the two extreme types.He interprets the behaviour in terms of a somewhat ill-defined ratio of theinteraction between the amphipathic substance and oil to that betweenthe amphipathic substance and water.This somewhat obscures thegeometrical factor in the amphipathic or, as this author prefers, " amphi-philic ", property. This is brought out in the section dealing with allseven n-tetradecane sodium sulphates,16 where, as previously mentioned,it is shown that the critical concentration for micelles in aqueous solutionincreases as the ionic group moves towards the centre of the chain, whichwould indicate on this author's view an increasing water attraction, andyet' the compounds behave as though more oil-attractive as far as solubilis-ation is concerned. The author apparently goes to an opposite extreme tothat visited by explorers with the X-ray diffraction camera, in that heminimises the importance of organised structure, although accepting theanistropic gel phase as a lamellar intermediate between the amicro-emulsionsof oil-in-water and water-in-oil forms envisaged by J.H. S ~ h u l m a n . ~ ~I n the other papers in this series, P. A. Winsor notes that the addition45 E. Angelescu and M. Popescu, Kolloid-Z., 1930, 51, 336.*13 Trans. Paraday SOC., 1946, 42, B, 165.47 Ibid., p. 170. 4 8 Ibid., 1948, 44, 37644 GENERAL AND PHYSICAL CHEMISTRY.of simple salts 49 can in part replace the addition of intermediate alcoholsby increasing the ratio of oil-phase attraction to water-phase attractionof the amphipathic substance. The effects of the nature of the oil phase 50and of that of the amphipathic substance 51 are examined, the latter supple-menting earlier work by R. Durand 52 on sodium soaps from C, to Cll.Solubilisation in glycol in place of water is also examined 53 and is dis-tinguished by absence of the anisotropic gel phases.The author considersthat the hydrogen-bonded pseudo-ice structure in water is necessary forthe adhesion between the units of dispersed phase without which gel structurecannot be evident.3. Organisation in Concentrated Solutions.of the production by clear solutions of soapsof an X-ray diffraction pattern of a much more definite nature than thatproduced by normal liquid systems threw new light on the problem of thestructure of these solutions. Unfortunately, the X-ray diffraction cameraas a precision tool is held in rather uncritical respect by many physicalchemists unfamiliar with the complications of the subject, and specialistsin the subject have been perhaps insufficiently familiar with other workon solutions of soap-like substances to have appreciated that there mightbe some doubt about apparently obvious conclusions from the measure-ments. The result has been that the advance following on this discoveryhas been much more rapid measured as a scalar than as a vector quantity.The diffraction patterns indicate the presence of a single characteristicshort spacing of about 4-6 A.and a long spacing, greater than twice thelength of the extended paraffin-chain ion, which increases with dilution.The diffraction ring due to the long spacing is not detectable at concen-trations of salt much under loyo, but that due to the short spacing is stillevident at less than 5y0.552 56J.Stauff examined the sodium salt of the C,, primary sulphate esterin parallel experiments at temperatures of 20°, where the salt exists as asuspension of microscopic curd fibres, and a t 75", where it is in clear solution.In the curd condition, two rings due to short spacings are evident and onedue to a long spacing which in this condition of the salt is, as expected,independent of concentration. Insolution the first two fuse together to a single constant value of 4-60 andthe second ranges from about 6 2 ~ . at 20% concentration of salt to 4 2 ~ .a t 80%.Following K. Hess and J. Gundermann 54 and H. Kiessig and W. Philip-The discovery in 1937The values are 4.55, 4.00, and 38.2 A.49 Trans. Faraday Soc., 1946, 42, By 382.51 Ibid., p.390.53 P. A. Winsor, Trans. Paraday SOC., 1948, 44, 451.54 K. Hess and J. Gundermann, Ber., 1937, .70, 1800.56 W. D. Harkins, R. W. Mattoon, and M. L. Corrin, J. Amer. O h . SOC., 1946,50 Ibid.? p. 387.52 Cornpt. rend., 1946, 225, 898.55 J. Stauff, Kolloid-Z., 1939, 89, 224.68, 220HARTLEY : AQUEOUS SOLUTIONS OF SOAP-LIKE SUBSTANCES. 45p ~ f f , ~ ~ Stauff interprets the short spacing as that between adjacent parallelplanes in which the chains lie parallel to one another, and the replacementof the two corresponding identity periods in the crystalline phase by asingle period as indicating that, during the transition of the curd suspen-sion to clear solution, partial fusion of the crystal occurs similar to thatin transition from a normal crystal to a smectic melt.In the crystal, allthe zigag C-C links of a chain are in the same plane and these planes areregularly disposed with respect to one another. In the smectic state thesechain planes, by virtue of freedom to rotate, have effectively becomecylinders. It will be noted that this process involves a lateral expansionamounting to some 15% on the original area, only some 5% of which isattributable to thermal expansion alone.All these and other 58’ 59 investigators have, until very recently, acceptedthe interpretation of the long spacing by Hess, Kiessig, and their collab-o r a t o r ~ . ~ ~ , 57 It is considered to have a similar origin to the constantlong spacing in the true crystal, which represents, of course, the distancebetween planes containing the terminal ionic groups, which planes arenearly perpendicular to the chains, The expansion of this spacing withdilution of the salt is considered to be due to the increasing separation ofthe pairs of ionic planes by a more or less organised layer of water.Thegeneral picture is that of an assembly of smectic-crystalline leaflets, theso-called laminar micelles, separated by layers of water of thicknesscharacteristic of the dilution.This concept may perhaps have been suggested by analogy with thequalitatively similar behaviour of montmorillonite clays onIn this well-established case, however, a water layer thickness of morethan 4 molecules has never been observed, whereas the laminar soap micellesmust be separated by up to a maximum of a t least 8 water molecules.Moreover, the clays remain insoluble.Any excess water produces a sus-pension of macroscopic particles of size determined by the origin and treat-ment of the clay and separated to distances determined by sedimentationconditions.This picture of regularly separated lamin8 has frequently been describedand equally frequently drawn. It has the merit of being easily drawn.The difficulty is to stop drawing it, and one may fairly ask whether Naturewould not find a corresponding difficulty. There is no doubt a t all thatthe clear solutions of paraffin-chain salts are equilibrium systems in thestrict sense, and no hysteresis of any exactly measurable property has yetbeen detected.Addition of further paraffin-chain ions to any one of thesepictures of the laminar micelle would seem to involve no difference from67 Naturwiss., 1939, 27, 593; see also K. Hess, W. Philippoff, and H. Kiessig,6 8 P. Krishnamurti, Indian J. Physics, 1929, 3, 307.6o See E. A. Hauser and L. S. Le Beau in Alexander’s “ CoIloid Chemistry ” (Rein-Kolloid-Z., 1939, 88, 40.D. Dervichian and F. Lschampt, Bull. SOC. chim., 1945, 12, 189.hold, 1946)’ Vol. 6, p. 19146 GENERAL AND PHYSICAL CHEMISTRY.the last additions in any way which could distinguish the chosen size asbeing energetically or statistically preferable. Only when clusters ofmolecules are very small will there be any optimum size in an equilibriumsystem unless some special factors operate to give the optimum size astrongly marked maximum potential energy loss for each molecule enteringthe cluster.Criticism along these lines has already been made in advance byK.H. Meyer and A. van der Wyk 6 1 directed against the Reporter’s hypo-thesis of an optimum size of micelle on thc mistaken assumption thatthe micelle considered had a parallel alignment of ions. It has been answeredby the Reporter elsewhere *033 for the case of the spherical micelle, butremains a very valid objection to the laminar micelle. I n developing atheory of a reversible aggregation colloid it is just as important to find amechanism for the limitation of aggregation as it is to find a primary causeof aggregation. The argument is therefore of some importance and it hasbeen so consistently overlooked that it is desirably briefly to repeat it.Aggregation of paraffin-chain ions is due to the very strong mutual attrac-tion of water molecules which tend to eliminate as far as possible theintrusion of indifferent paraffin between them, The strong attractionbetween water and the ionic end groups is responsible for limiting thisprocess of extrusion of the separate chains into clusters presenting a muchsmaller area of paraffin to the water.If the arrangement is laminar, how-ever, this would explain only a limitation of the thickness of the micellesand leave their area indeterminate. If the greater entropy of the liquidarrangement of the paraffin chains causes this state to be preferred (andwhere it does not do so we have in fact indefinite laminq i.e., our salt isinsoluble), then a spherical cluster will result, the single linear dimensionof which is now controlled by the balance of forces referred to.If thespherical micelle were much smaller than necessary to enable a fullyextended chain to penetrate from its surface to the centre, a greater areaof paraffin than necessary would be exposed to the water. If it weremuch larger, then ionic groups would have to leave the water against thestrong attraction of the latter, or the assembly would have to deviate fromspherical form and so the entropy would be reduced. It is perhaps desir-able to recall that a strongly marked optimum size of micelle, varying butlittle with concentration of paraffin chain or added salts, is an experimentalfa~t.~OA similar difficulty about the laminar micelle theory was raised byJ.D. Bernal in the Faraday Society Discussion on Swelling and Shrinkingin comment on the contribution by D. G. Dervichian.62 He pointed outthat a simple calculation showed that the increase of spacing betweenalternate ionic planes, if assumed to be due to entry of water betweenneighbouring planes, could account only for a fraction of the total waterpresent. To take an example from J. Stauff’s data 55 on the C,, sodiumHdv. Chim. Acta, 1937, 20, 1321. 62 Trans. Paraday SOC., 1946,42, B, 180HARTLEY : AQUEOUS SOLUTIONS OF SOAP-LIRE SUBSTANCES. 47sulphate, in a system containing 40% of water, the long spacing has increasedfrom its “ dry ” value of 38 A.to 48 A. This will account for 16% only ofthe water. The remaining 24% must separate the indefinite lamellaelaterally, where it will be in contact with the exposed sides of the parallelbundles of paraffin chains.Before considering the latest developments in this subject, mentionmust be made of a further quantitative difficulty in the lamellar hypo-thesis, pointed out by W. D. Harkins, R. W. Mattoon, and M. L. Corrin @after following up, in a more extensive investigation, Kiessig and Philippoff’sobservation 57 that the long spacing is increased by dissolving (“ solubilising ”)oils in the soap solution. They consider that the oil is located as anotherlayer, this time between the planes defined by the terminal methyl groups.The difficulty here is the reverse of that found in accounting for the watervolume, in that oil increases the spacing by niuch more than would beexpected from its inclusion in this location without other changes in thesystem.The authors are therefore forced to the view that the introduc-tion of the oil layer has a secondary effect, by some unknown mechanism,on the water layer.I n a later paper, Harkins et aZ.64 report the results of more thoroughinvestigation of the X-ray diffraction photographs which reveal a new,less well-defined, long spacing attributed to the individual thickness ofthe micelle. At this stage they favour a cylindrical micelle with theparaffin chains parallel to the cylinder axis. They envisage the inter-pretation of the original long spacing on a point lattice system in which“ no special shape for the micelle is necessary ’,.In this paper the diffusion-measurement evidence*O for the size of the micelle is for the first timeconsidered in relation to the X-ray studies. The cylindrical model hasbeen further considered byM. L. Corrin has recently briefly reviewed the X-ray diffraction evidencefrom the point of view of the spherical micelle hypothesis, and finds thetwo not inconsistent. He considers that “ the observed patterns can arisefrom a system of spherical micelles and that the Bragg law ‘spacings’may be meaningless ”. The communication is too brief to permit thederivation of the distance distribution functions which he proposes, and afuller treatment by this author will be awaited with interest.The Reporter had already suggested 66 that a distortion of the sphericalmicelles might occur, owing to packing effects operating in the concentratedsolutions examined by the X-ray technique.Such effects were not con-sidered in the development of the theory of spherical micelles from evidencebased only on measurements in dilute solution. It now appears unnecessaryto envisage such distortion. It would presumably give rise to a morerather than a less complex diffraction picture. Once the principle is admitted63 J . Colloid Sci., 1940, 1, 105.64 R. W. Mattoon, R. S. Steams, and W. D. Harkins, J . Chem. Physics, 1947,15, 209.6 5 Idem, ibid., 1948, 16, 156.6 6 G. S. Haxtley, Trans. Faraday SOC., 1946, 42, B, 648 GENERAL AND PHYSICAL CHEMLISTRY.that the corresponding, regularly spaced assemblies of atoms responsible forthe diffraction need not be planes, the spherical micelle offers much thesimplest explanation of the diffraction phenomena.In a recent con-tribution 67 the Reporter has suggested that the strong electrostatic repul-sion between the micelles will, in concentrated solution, cause them to bemore or less regularly disposed and in such a way that each is the maximumdistance from the maximuin number of neighbours. This condition issatisfied by the three dimensional " honey-comb " or close-packed assembly,the geometry of which leads directly to the simple relationshipI = (3+/22/2x)*rwhere I is the distance between centres of ncighbouring spheres, r theirradius, and + the fraction of the total volume occupied by the spheres.It is shown, not only that this equation leads to a good approximation tothe observed variation of I (the " long spacing ") with 4 on the assumptionof constant r, but that the calculated values of r are, as expected and as foundby diffusion measurements, slightly greater than the length of a fullyextended chain.Not only is the water thus accounted for, but this view of the structureexplains also the anomaly of a disproportionately great increase of I onaddition of oils, A non-polar oil will be contained mainly in the interiorof the micelle and tend to be concentrated near its centre, so that a maximumincrease of radius results from the addition of a small amount of oil.Inthe extreme case, let the oil be located exclusively a t the centre, occupyinga sphere of radius 6. The whole micelle now has radius r + 6, and theparaffin chains occupy the volume $ x [ ( r + 6)3 - s3]. The volume ratio ofadded oil to paraffin chains is thus, in the limit of 6 -+ 0, equal to a2/3r2.The relative increment of T resulting from addition of an amount of oilcorresponding to a small fraction f of the paraffin-chain volume will thusbe dv, whereas the relative increment of spacing in the simple laminarmodel will be equal to f. A disproportionate increase of I follows directlyfrom that of r .J. H. Schulman and D. P. Riley 68 have published an investigation byX-ray diffraction technique of the transparent emulsion systems previouslydescribed by the former.46 They interpret their results in terms of thelattice point distances of the emulsion droplets, and the investigation showshow far this simple view is applicable. They find evidence of the distortionwhich must occur when the ratio of dispersed phase exceeds the 74% corre-sponding to close packing of equal spheres. These authors issue a cautionagainst the full acceptance of their model for the case of solutions of theparaffin-chain salts alone on the ground that an ideally liquid sphericalmicelle would not show the characteristic short spacing found in photo-graphs of these solutions.It is to meet this difEculty that Harkins et al.propose a micelle with a cylindrical, parallel-packed core rounded off a t67 Nature, in the press.68 J. Colloid Sci., 1948, 3, 383HARTLEY : AQUEOUS SOLUTIONS OF SOAP-LIKE SUBSTANCES. 49the sides with more randomly-packed chains presenting their ionic groupsto the water.The short spacing cannot be due to regular disposition of ionic groupson the outside of the micelle. Diffusion measurements4() indicate aneffective radius for the cetylpyridinium micelle of about 25 A. This willcontain between 70 and 100 para&-chain ions. The mean distance apartof the ionic groups will therefore be not less than 8.5 A. The outer diffrac-tion band probably arises from a regular spacing between paraffin chains.No exact compiwison seems to have been made with the pattern producedby a liquid paraffin of comparable chain length, to see whether the trueliquid in bulk has sufficient regions of ordered arrays to make any furtherexplanation necessary.It has been mentioned above that the soaps, and perhaps other salts ofyaraffin-chain anions, have less solvent power than those of paraffin-chaincations.The long spacings also appear to be greater in the latter, indicatinga larger m i ~ e l l e . ~ ~ It is a question worthy of further study, by all methodsavailable, whether there may be more internal order in the anionic micelles.That the spherical liquid micelle is not a complete explanation of allthe properties of paraffin-chain salt solutions has always been appreciatedby the Reporter. Although many solutions, even when concentrated, haveviscosities little in excess of that of water, yet others may be very viscousor gelatinous over a limited range of temperatures or even show a permanentelasticity persisting to very low concentration^.^^ The latter effect is veryspecifically influenced even by the nature of the small ions.The occurrenceof pronounced elasticity in very dilute solutions indicates that, in thesecases, very stable filamentous particles must be present. One may imaginethat an indefinitely long cylindrical form of the paraffin micelle is pre-ferred in these cases, with the paraffin chains parallel to the axis, as inHarkins’s but adhering together by the ionic lattices, which wouldaccount at once for a specific ion effect. On the other hand, the chainsmight be as chaotically disposed as is geometrically possible, with the ionicgroups on the cylindrical surface, an arrangement which we should expectto be more probable in view of the factors causing limited aggregation ofamphipathic ions.A filamentous arrangement is suggestively similar tothe “ myelinic figures ” described by D. G. Dervichian.62 The very highdegree of elasticity shown suggests that the filaments must be elasticallycontractile. The liquid cylinder would have this property, since it wouldbe extensible without disruption and its surface would tend to contract tothe smallest area consistent with the radius not exceeding the effectivestretched length of the chain ion.Optical anisotropy has been a much neglected method of enquiry intothis subject. Its occurrence in streaming suspensions of soap curd is, ofcourse, well known, as also the strong birefringence of the gelatinous phasesformed in many systems where organic liquids are present within certainO9 G.S . Hartley, Nature, 1938, 142, 16150 GENERAL AND PHYSICAL CH1MISTRY,concentration limits 48 and at sufficiently high concentrations of the puresalts. ' 0 The ordinary solutions should also show streaming birefringenceif the micelle were indeed of laminar form.In the course of pioneer studies of the aggregation of lower fatty acidsand soaps which revealed the existence of the critical transition fromultimately dissolved to aggregated solution, J. Grindley and C. R. Bury 71studied the changes in a number of physical properties, including that ofdensity.They found that aggregation resulted in a decrease of the partialvolume of water and an increase in that of the solute. The importance ofthis fact has not been generally recognised. The Reporter 66 has drawnattention to the fact that the expansion of the salt may be so great as togive rise to an increase in the volume of the whole system, water pluscrystalline salt, when solution occurs. Since the partial volume of a simpleelectrolyte is always smaller than its volume in the solid state, the expan-sion of the paraffin-chain salt must be due to increase of volume of theparaffinic portion, which would, of course, be expected on transition of theorganised crystal lattice to a liquid arrangement.Density measurements on solutions of the higher paraffin-chain saltsare not sufficiently exact and comprehensive to enable a precise estimateof the density of the paraffinic portion of the micelle to be made.Takingthe data at 25" for potassium we find that the differences of partialmolal volumes between the octoate and propionate are 79.2 C.C. a t 0 . 3 ~ whereno aggregation is evident and 88.9 C.C. a t 1 . 0 ~ where it is effectively corn-plete. Correspondingvalues derived from the difference between octoate and acetate are 13-1and 14.5 C.C. per g.-mol. CH,. The volumes per g.-mol. CH, in liquidparaffins obtained from densities of hexane, octane, decane,and hexadecaneare fairly constant a t about 16.3 C.C.tri-methylammonium bromides from the differences between which we maysimilarly deduce volumes per g.-mol.CH, (average between 0.1 and 0 . 4 ~ )to be 16.5 c.c.*The partial volumes even in simple electrolytes, such as potassiumacetate, vary considerably with concentration and the significance of densitymeasurements, as well as the provision of more accurate data, is a matterwhich merits further consideration. There is a prima facie case that theinterior micelle density in the higher paraffin-chain salts is a t least as lowas that of the liquid hydrocarbon.Harkins and his collaborators 63 report density measurements onThe volumes per CH, group are 13.2 and 14.8 C.C.Scott and Tartar l8 record densities a t 25" of the C,,, CI2, and70 J. W. McBain and E. Gonick, J. Amer. Chem. SOC., 1946, 68, 683.71 J., 1929, 679.* Professor E.C. Lingafelter has kindly communicated to the Reporter the follow-ing density figures atl 25". For the C, compound at O . O ~ N , 1.00046; for C, and CBcompounds at 0 . 2 ~ , 1.00321 and 1.00160. From these data we obtain the followingvalues for the volumes per g.-mol. of CH,. From the difference C,,-C8 at O . ~ N , 16.25.From the difference C1,-C, at O - ~ N , 16.0.7 2 D. G. Davies and C. R. Bury, J., 1930, 2263.From the difference Cl,-C, at O*~N, 16.5WILLIAMS AND SINGER : CHEMICAL KINETICS. 51potassium laurate solutions in which n-heptane and 1 : 2 : 3-trimethyl-butane and2* ethylbenzene were dissolved. The first and the last liquidhave, in the solutions near saturation, apparent densities nearly equal tothose in the bulk liquids, but, in very dilute solution of the added liquid,the apparent densities are considerably higher.This might be expected if weconsider the micelle, straining to be as large a s possible, to be not com-pletely filled in the centre until non-polar molecules are added. 1 : 2 : 3-Trimethylbutane, on the other hand, has an apparent density in dilutesolution approximately equal to tha.t in bulk and a higher density nearsaturation. Its bulk density is considerably higher than that of n-heptaneand any volume change occurring on solution in bulk in normal paraffinswould need to be known before speculation on this remarkable result wouldbe profitable.G. S. H.3. CHEMICAL KINETICS : HOMOGENEOUS THERMAL GAS REACTION&I n his Presidential Address to the Chemical Society, Sir Cyril Hinshel-wood has discussed, in terms of general principle, the present position ofchemical kinetics. It has become evident that the overall “reactionorder” has not now the theoretical significance which it may once haveappeared to possess, however important the concept may still be as apractical tool of the experimenter. Most reactions take place in a seriesof stages, either as chain processes, involving interactions between freeatoms and radicals, or as non-chain reactions, in which, again, each individualstep may be of great siniplicity.Correspondingly, there has been, in recent years, great interest in theindividual reactions of free atoms and radicals and progress in thisdirection has been reviewed in Annual R e p ~ r t s .~ However, these Reportshave not, for many years: reviewed the overall kinetics of gas reactions;and this is the subject of the present Report. In so large a field it is im-possible to be exhaustive, so we have deliberately selected reactions (payingsome attention to examples which have been important in the history ofreaction kinetics) 5, 6, 7 to illustrate the kind of progress which has beenmade. In order to concentrate upon overall kinetics, we have had toleave without mention much important work upon elementary reactions,such as that of Steacie with hydrogen atoms.J . , 1947, 694.E.g., cf. E. W. R. Steacie, “Atomic and Free Radical Reactions,” New York,1946 ; and Faraday Society Discussion, 1947, 2, on the “ Labile Molecule.”Cf.M. Ritchie, Ann. Reports, 1940, 37, 79; C. E. H. Bawn, ibid., 1943, 40, 36;D. H. Hey, ibid., 1944, 41, 181; W. A. Waters, ibid., 1945, 42, 130; J. Weiss, ibid.,1947, 44, 60.Cf. ibid., 1934,31, 46; 1935, 32, 89; 1936,33, 86; 1937, 34, 43.Hinshelwood, “ Kinetics of Chemical Change in Gaseous Systems,” 3rd edn.,H. J. Schumacher, “ Chemische Gssreaktionen,” Dresden and Leipzig, 1938. ’ R. N. Pease, “ Equilibrium and Kinetics of Gas Reactions,” Princeton, 1942.Oxford, 1934; “ The Kinetics of Chemical Change,” Oxford, 194052 GENERAL AND PHYSICAL CHEMISTRY.Overall Order of Reaction.Second-order Reactions.-The formation and decomposition of hydrogeniodide stand out in exhibiting a second order which bears a direct relationto the molecular events which determine reaction.(For newer work onthese and the corresponding reactions of deuterium compounds, cf. A. H.Taylor and R. H. Crist.8) The fate of other reactions which have, a t onetime or another, been formally classified as second-order reactions may beillustrated by the example of the thermal decomposition of acetaldehyde.The earlier work upon thisreaction has been critically reviewed by Pease ; and the conflicting evidenceas to whether the decomposition occurs by a chain mechanism or not hasbeen summarised by J. R. E. Smith and C. N. Hinshelwood? who havereinvestigated the reaction. Points in favour of a chain mechanism are :(1) Very careful work by M. Letort lo showed that the order was 1.5, inagreement with the Rice-Herzfeld theory 31 of chain reactions.(2) Thereaction appeared to follow a mechanism similar to that of the photo-chemical decomposition which was known to involve free radicals.ll (3)The rate was reduced by propylene.12 (4) Theoretical arguments based onspectroscopy had been advanced to show that internal rearrangementpreceding dissociation was ~n1ikely.l~ (5) The presence of free radicalshad been e~tab1ished.l~ On the other hand, there was some evidence againsta chain mechanism. (1) Nitric oxide seemed normally not to inhibit the reac-tion.15 (3) The reactionappeared to be similar to that of the " fully inhibited " decomposition ofbenza1dehyde.l' The reaction had been found to exhibit 8 variable orderand the simultaneous occurrence of more than one mechanism had beenpostulated.l 8find that increasing additions of propylenereduce the rate of decomposition a t 550" until a limiting value is reached;further additions of propylene have a slight catalytic effect. They also findthat nitric oxide does reduce the reaction rate only at low acetaldehydepressures ; a t moderate pressures inhibition is masked by a strong catalyticeffect. The reaction proceeding with the limiting rate attained by " fullinhibition " with propylene is of approximately second order ; and a velocitycoefficient calculated for a bimolecular collisional activation involving twosquare terms agrees well with the observed value (as it does also for form-aldehyde). By subtracting the '' fully inhibited " from the normal rate,T h e thermal decomposition of acetaldehyde.(2) Too few free radicals appeared to be present.16Smith and HinshelwoodJ .Amer. Chem. SOC., 1941, 63, 1377.A. 0. Allen and D. V. Sickman, J. Amer. Chem. SOC., 1934, 56, 2031.Proc. Roy. SOC., 1942, A , 180, 237.lo J . Chim. physique, 1937, 34, 206, 265, 355, 428.l2 F. 0. Rice and 0. L. Polly, J . Chena. Physics, 1938, 6, 273.l3 T. W. Davis and M. Burton, ibid., 1939, 7, 1075.l 4 M. Burton, J. E. Ricci, and T. W. Davis, J. Amer. Chem. SOC., 1940, 62, 265.l5 L. A. K. Staweley and C. N. Hinshelwood, J., 1936, 812.l6 F. Patat and H. Srachsse, 2. physikal. Chem., 1936, B, 31, 105.l7 R. E. Smith and C. N. Hinshelwood, Proc. Roy. Soc., 1940, A, 1'95, 131.la C. J. M. Fletcher and C.N. Hinshelwood, ibid., 1933, A, 141, 41WILLIAMS AND SINGER : CHEMICAL KINETICS. 53it is possible to investigate the part of the reaction which may be assumedto be due to a chain mechanism; it appears to be of the first order.The simultaneous occurrence of a molecular and a chain reaction hasbeen proved in a very satisfactory manner by J. C. Morris,lg who decom-posed mixtures of fully deuterated and ordinary acetaldehyde at 542".Great pains were taken to purify the materials, and in particular to removeall traces of oxygen, and to reduce the polymerisation of the aldehyde toa minimum. When this careful pretreatment is applied, the decompositionproducts contain mainly CH,, CD,, and CO, and only small amounts ofmixed methanes (CH3D, etc.).The reaction can therefore proceed neitherby a chain mechanism (involving CH, radicals) nor by a bimolecular processsuch as\ * \ CH3 D ,,'\ / \ ,,' oc"'\ . \ I, + :, CO=CH,D+ CD3H+2C0'\ /Moreover, the reaction rates observed for the highly purified materialapproach those of Smith and Hinshelwood's " fully inhibited " reactionand are lower than the rates observed by all other investigators.On the other hand, when "untreated" mixtures of CH3*CH0 andCD3*CD0, or mixtures of " pretreated " materials to which small amountsof oxygen had been added, were decomposed, the products contained largeamounts of CH3D, CHD,, and-surprisingly-CH,D,.Neither prolonged heating of mixtures of CH,, CD,, CO, and traces ofO,, nor the decomposition of pure CH,*CHO in the presence of CD, andCO gives rise to the formation of appreciable amounts of mixed methanes.These results appear to prove (though this is not fully accepted bySteacie2) that the decomposition of pure acetaldehyde proceeds by aunimolecular mechanism, and that the presence of minute amounts ofimpurities-in particular of oxygen-gives rise to a chain reaction.Morrisestimates that " untreated " aldehyde decomposes to the extent of 50%by a chain mechanism. Smith and Hinshelwood's work indicates 60-70% of chain mechanism. The discrepancies between the rates reportedfor this reaction can be readily understood. Not even Morris's carefultreatment succeeded in reducing the chain reaction to below 10-20~0 ofthe overall rate.Although this work explains much that has baffled previous investigators,it raises some new problems.The order of the moEecuEar reaction remainsin doubt. The appearance of appreciable amounts of CH,D, among theproducts of the chain decomposition does not lend support to the chainmechanisms that have been suggested. One may also wonder whethersmall amounts of oxygen or other impurities are not responsible for thechain mechanism in other reactions where this has not been suspected.The effect, of oxygen on the decomposition of acetaldehyde has beenThe order of the reaction is still between 1 and 2.l9 J. Amer. Chem. SOC., 1944, 66, 58454 GENERAL AND PHYSICAL CHEMISTRY.further investigated by M. Letort and N. M. LetorL20 Pure acetaldehydeis thermally stable below 400", but in the presence of oxygen the rate ofdecomposition is still measurable at 150".I n mixtures of acetaldehyde(237 mm.) and 0.1-20 mm. of oxygen only definite fractions of aldehydeare decomposed. It is thus possible to calculate the number of molttculesdecomposed by one molecule of oxygen. This number varies with thetemperature in a surprising manner, giving rise to an N-shaped curve.There is a maximum of 200 at 200", followed by a minimum (65) a t 315",after which the curve rises steeply. The curve obtained by plotting thelogarithm of the initial velocity against 1/T shows a bend at 190". Itappears that the activation energy is 13 kcals. below 180" but 24 kcals.a t 200-290".Experiments of E. Leifer and H. C. Urey,21 who followed the decompos-ition of acetaldehyde by means of an interesting, though as yet inaccurate,new mass-spectrographic technique, indicate a second-order reaction.Free radicals obtained by the pyrolysis of diacetyl strongly catalysethe decomposition of acetaldehyde and other compounds.22 This catalysisis not reduced by the presence of nitric oxide, although in the case of di-methyl ether, the diacetyl-promoted pyrolysis is strongly inhibited bynitric 0xide.~3The decomposition of acetaldehyde is also catalysed by hydrogensulphide. W.L. Roth and G. K. Rollefson2* found the reaction to behomogeneous. No hydrogen sulphide is consumed by the reaction, and theproducts are methane and carbon monoxide as for pure acetaldehyde.The overall activation energy is 36 kcals.(the value found by Smith andHinshelwood in the absence of catalysts is 47 kcals.).Third-order Reactions.-Interactions of nitric oxide with oxygen andwith halogens are the classical third-order 6~ 73 3* although thesehave not always been held to demand a termolecular process as the vitalstep. However, the reaction of nitric oxide with chlorine is subject toheterogeneous complications; 25 and it is not certain that the oxidation ofnitric oxide is free from them. I n new work on the vexed question of" intensive drying," E. M. Stoddart 26 reported non-interaction betweenoxygen and nitric oxide, intensively dried in separate vessels, but onlywhen mixing of the gases took place in the oxygen-containing bulb. Heinferred that heterogeneous processes, influenced by adsorbed moisture,were essential to the oxidation of nitric oxide, contrary to M.Bodenstein'soriginal view. F. B. Brown and R. H. C r i ~ t , ~ ~ using very carefully purifiedgases, find the oxidation of nitric oxide to be of third order, at 25", for 3-and &fold variations of reactant concentrations, with pressures of nitric2o Compt. rend., 1948, 226, 77.22 F. 0. Rice and W. D. Walters, ibid., 1941, 63, 1701.23 C. I€. Klute and W. D. Walters, ibid., 1945, 67, 550.24 Ibid., 1942, 64, 1707,2s E. M. Stoddart, J., 1940, 823; 1944, 388.26 J., 1939, 5.21 J . Amer. Chem. SOC., 1942, 64, 994.27 J . Chem. Physics, 1941, 9, 840WILLIAMS AND SINGER : CHEMICAL KINETICS. 65oxide between 0.01 and 0.1 rnm. and of oxygen between 8 and 22 mm.The rates observed differ from those of Bodenstein (obtained with about10 mm.pressure of each reactant) by 5*5y0. Brown and Crist 27 have alsoexamined the reaction NO, + CO = CO, + NO (found to be of secondorder) a t 225-290'; and they have investigated the products and ratesof reaction occurring in mixtures of nitric oxide, oxygen, and carbon mon-oxide a t 25-265". In the ternary mixtures they observe the formationof carbon dioxide a t temperatures which are too low for it to be ascribedto the above reaction between carbon monoxide and nitrogen dioxide.Moreover, experiments a t higher temperatures,28 with the ternary mixturesof NO, 0,, and CO, gave reaction rates proportional to the first power ofthe nitric oxide concentration.These two facts are inconsistent with themechanism2N0 + 0, = 2N0,and Brown and Crist propose the reactionsto account for a t least part of the third-order oxidation of nitric oxide,together with NO, + CO = NO, + CO, for the ternary mixtures containingcarbon monoxide.Heterogeneous reactions occur in the mixtures containing carbon mon-oxide ; but the above niechanisrn applies to homogeneous reaction studiedin Pyrex glass vessels rinsed with potassium chloride solution.The oxidation of nitric oxide by nitric acid vapour has been studied.29The reaction has " some termolecular characteristics " but surface effectsoare prominent.At onetime it was argued that unimolecular processes in gases could not resultfrom collisional activation.Then the Lindemann-Hinshelwood theory (sub-sequently elaborated) showed that they could ; and first-order gas reactionswere discovered experimentally. A little later these were interpreted bysome as chain reacti0ns.3~ Still more recently, it has been held (cf. R. N.Pease 7 9 32) that many of the apparently first-order decompositions, whichfurnish the subject matter for the whole discussion, are, in fact, betterrepresented experimentaZZy as reactions of order 1.5.One reaction, whose first order has never beendenied, is the thermal decomposition of dinitrogen pentoxide vap0ur,3~which, indeed, retains its speed and first order down to embarrassingly low28 G. M. Calhoun and R. H. Grist, J . Chem. Physics, 1937, 5, 301 ; R. H. Grist andJ.E. Wertz, ibid., 1939, 7, 719.29 J. H. Smith, J . Amer. Chem. SOC., 1947, 69, 1741.30 Cf. H. C. Ramsperger, Chem. Reviews, 1932, 10, 27.31 E.g., F. 0. Rice and K. F. Herzfeld, J . Amer. Chem. SOC., 1934, 56, 284; J . Chem.Physics, 1939, '7, 671; cf. F. 0. Rice and E. Teller, ibid., 1938, 6, 489; A. Kossiakoffand F. 0. Rice, J . Amer. Chem. SOC., 1943, 65, 590.NO, + CO = NO + CO,NO, + NO = 2N0, NO + 0, + NO,First-order Reactions.-The history of these is a curious one.Dinitrogen pentoxide.32 J . Chem. Physics, 1939, 7, 749.' 'E.g., cf. F . Daniels, " Chemical Kinetics," Ithatea, New York, 193856 UENERAL AND PHYSICAL CHEMISTRY.pressures (of the order 0.05 mm.). An abnormally large collision diameterwas proposed to account for this.= Doubt has been expressed whetherthe diminution of speed a t even this low pressure is due to the expectedtheoretical insufficiency of the rate of activation.F. Daniels and P. L.Veltman 35 suggested, as a chemical explanation, that the interaction ofnitric oxide and dinitrogen pentoxide, assumed to be a rapid step, in boththe old and the new mechanism (see below) for the dinitrogen pentoxidedecomposition, might, a t very low pressures, have a speed comparablewith that of the dissociation of N205 molecules. J. H. Smith and F. Daniels 36find the reaction between dinitrogen pentoxide and nitric oxide, a t 0-25",with reactant pressures from a few hundredths of a mm. up to 20 mm.,to be susceptible to catalysis by moisture and surface. The rate of anessentially homogeneous reaction in vessels coated with paraffin is approxini-ately proportional to the pentoxide concentration and nearly independentof nitric oxide concentration, particularly a t low pressures of the latter.The overall reaction is proved to beN205 NO = 3N02and the mechanism suggested tentatively isN,05 -+ NO, + NO, (slow) NO, + NO = 2N0, (fast)A new interpretation for the dinitrogen pentoxide decomposition has beensuggested by R.A. Ogg?' who proposes the mechanism(1) N,O5 ---+ NO, + NO, (4)(2) NO, + NO, = N,O, (k2)(3) NO, + NO, = NO, + 0, + NO (k3)(4) NO + N,O, = 3N02 (rapid)There being reason to suppose that k, << E,- d",O51/dt = 2dTr\JOI/dt = 2k,k",O,I/(h + k3) - (2~1/k#,[N,O5]The apparent first-order constant is thus a product of an equilibrium con-stant E1/k, and a bimolecular constant k,.The theoretical grounds foranticipating a diminution of order and rate a t low pressures thereforevanish.The theory of unimolecular decompositions wasfounded upon three main groups of reactions. These were the decompos-itions of ethers and of azo-compounds 30 and certain isomerisation pro-cesses. As already mentioned, both the experimental and the theoreticalinterpretation have been questioned.Whatever be the theoretical interpretation, it can scarcely be deniedthat there exist homogeneous gas reactions which are empirically of the34 L. S. Kassel, " The Kinetics of Homogeneous Gas Reactions," New York, 1932;cf. R. H. Fowler and E. A. Guggenheim, " Statistical Thermodynamics," Cambridge,1939, p.525.PyroZyses of vupours.3 5 J . Chem. Physics, 1939, 7 , 764.37 J . Chem. Physics, 1947, 15, 3.37; cf. 0. K. Rice, ibid., p. 689.36 J . Amer. Chem. Soc., 1947, 69, 1735WILLIAMS AND SINGER : CHEMICAL KINETICS. 57first order over a limited range of conditions. For example, the decompos-ition of benzylideneazine 38 at 335" gives first-order velocity coefficients,independent of the initial pressure, in individual experiments ; and the timefor a, given fractional decomposition is constant for initial pressures rangingfrom 5 mrn. (tt = 4.6 mins.) to 378 mm. (t - 4.2 mins.). The discussionturns, however, on reactions observed over mder pressure ranges. Accord-ing to the theory of unimolecular decompositions, the first-order behaviourprevailing a t high pressures may be expected to change over and approachsecond-order kinetics a t sufficiently low pressures.R. N. Pease 7 7 32 hasput forward the view that many of the reactions which have been inter-preted as unimolecular decompositions are better represented, experi-mentally, over the whole range of pressures as reactions of order 1.5. Thebest example is the decomposition of diethyl ether. The supposedly first-order velocity coefficients attained a t 0.5 atm. pressure have been foundto rise further when pressures up to 20 atm. (and later up to 3.00 atm.)are used (for refs., see Pease '). Pease represents the reaction over thewhole pressure range as one of order 1.5, with a velocity coefficient con-stant within a factor of 2.This would correspond to a mechanism of thetype : Et,O+R ; R + Et,O+products + R ; 2R+X.Questioning also the " unimolecular " interpretation of the azomethanedecomposition, on the ground that this reaction is chemically far morecomplex 39 than had been supposed, so that pressure measurements are nota safe guide in measuring the reaction velocity, Pease concluded that theisomerisation of cyclopropane to propylene was the only reaction to whichthe theory of unimolecular reactions could properly be applied. In a newinvestigation of this reaction, E. S. Carner and R. N. Pease 40 have observed,a t 500°, first-order velocity coefficients which do not appear to fall by morcthan some 8% for initial pressures of 910--150 nim.; but then fall sub-stantially as the initial pressure is reduced to 10 mm.A velocity coefficientderived from a radical mechanism is very satisfactorily constant over thewhole initial pressure range. The effects of added gases fail to decidebetween the " unimolecular decomposition " and '' free radical " mechan-isms. Nitric oxide, propylene, ethylene, and hydrogen are practicallywithout influence upon the rate of reaction. In the presence of decom-posing n-butane, the isomerisation is accelerated.(1) As pointed out byHinshelwood,4l a chain mechanism, of the type quoted above for ether,itself involves a unimolecular decomposition as one step. (2) The repre-sentation of vapour decompositions as processes of order 1-5 is based onthe data for reactions whose chain components have not been inhibitedby nitric oxide.Even if the experimental order is accepted as unity, it had earlier been38 G.Williams and A. S. C. Lawrence, Proc. Roy. SOC., 1936, A , 156, 444.38 E. W. Riblett and L. C. Rubin, J . Amer. Chem. Soc., 1937,59, 1537 ; H. A. Taylorand F. P. Jahn, J . Chem. Physic.s, 1939, 7 , 470.4u J . Anzer. Chem. SOC., 1945, 67, 2067.*rThe whole discussion calls for two remarks.4 1 J . , 1948, 53158 GENERAL AND PHYSICAL CHEMISTRY.argued,31 with supporting experimental evidence, that the reactions werenot unimolecular decompositions, but chain reactions, proceeding bymechanisms which happened to give an experimental first order. ThiBquestion was resolved by the discovery 59 42 that chain components in thesedecompositions could be inhibited by small additions of nitric oxide, whichreduced the rate of decomposition to a fraction of its original value, inde-pendent of further additions of nitric oxide over a certain range.Theresidual reaction was taken to be a genuine unimolecular decomposition.Certain reactions appeared to defy retardation by nitric oxide ; amongthem were the decompositions of acetophenone43 (in contrast to that ofbenzaldehydel') and of acetone (and also of ethyl vinyl ether43a). How-ever, J. R. E. Smith and C. N. Hinshelwood44 have found the decom-position of acetone to be partially inhibited by propylene l2 and also bynitric oxide, which must be applied in rather larger amounts than usual,indicating a low mean chain length.Both the uninhibited and the residualreactions are of first order at pressures >lo0 mm. a t 570". (For otherrecent work on acetone, see Steacie ; also G . M. Harris and Steacie 45 andV. B. Falkovsky and M. Ya. Kagan.46) Rather similar results have beenobtained for methyl ethyl k e t ~ n e . ~ ~ a Much nitric oxide is needed toproduce a small retardation in the initial stages; and the decomposition isthought to be unimolecular. The activation energy of 67.2 kcals. is ascribedto rupture of the methyl-carbonyl bond (cf. E = 68 kcals. for the uninhibiteddecomposition of acetone).It could still be held, however, that the residual reaction was a chainreaction and that nitric oxide could start, as well as stop chains; l2 andidentity of reaction products in the decomposition of n-butane a t 525":'in absence and in presence of nitric oxide, has been considered to supportthis view.It has been countered, however, by J. R. E. Smith and C. N.Hinshelwood: who find that nitric oxide and propylene reduce the rate ofreaction to the same residual value in the decomposition of diethyl etherand also in that of propaldehyde. Moreover, the decomposition of prop-aldehyde, maximally inhibited by nitric oxide, is not further retarded bypropylene. This is strong evidence that the residual reactions are freefrom chains. With diethyl the residual reaction is of first order.The products are essentially the same for the normal reaction and for thereaction inhibited by nitric oxide.With propaldehyde and benzaldehydeit is approximately of second order.gAmong other instances of inhibitory action by nitric oxide, it has been42 L. A. K. Staveley and C. N. Hinshelwood, J . , 1937, 1568.43 R. E. Smith and C. N. Hinshelwood, Proc. Roy. SOC., 1940, A , 176, 468.43a S. N. Wang and C. A. Winkler, Canadian J . Res., 1943, B, 21, 97.44 Proc. Roy. SOC., 1945, A , 183, 33.4% J . Physical Chem. Russia, 1948, 22, 445.460 C. E. Waring and W. E. Mutter, J . Amer. Chem. SOC., 1948, 70, 4073.47 E. W. R. Stemie and H. 0. Folkins, Canadian J . Res., 1940, B , 18, 1.48 J. G. Davoud and C. N. Hinshelwood, Pmc. Roy. Xoc., 1939, A , 171, 39; 1940,46 J . Chem. Physics, 1944, 12, 554.A, 174, 50WILLIAMS AND SINGER : UHEMICAL KINETICS.58noted that 1% of this causes an extreme lengthening of the inductionperiod preceding the homogeneous dimerisation of acetylene at 400-700°.49 Transient inhibitory action by nitric oxide has been observed inthe decomposition of n-butane 50 and of methyl n-butyl ether.51 With thelatter, cyanide was detected in the reaction products, as in some otherreactions inhibited by nitric oxide. It has been suggested 52 that, in com-bining with methyl radicals, nitric oxide forms CH,*NO, which isomerisesto formaldoxime CH,:NOH. Formaldoxime 52 decomposes at 350-415" ina first-order reaction (up to half-life above 400"), primarily to hydrogencyanide and water. The activation energy of 39 kcals. is close to the N-0bond energy (37.7 kcals.) in alkyl nitrites.53 With hydrogen atoms, nitricoxide may form HNO.@ Formaldoxime has actually been isolated in theproducts of interaction of nitric oxide with free radicals from decomposingdi-tert.-butyl peroxide.58 The value 6.5 kcals.has been estimated for theactivation energy of interaction of nitric oxide with methyl radi~als.5~ The" inhibition curves " describing the influence of inhibitor concentration uponthe extent of inhibition (which are, for example, independent of diethylether pressure for nitric oxide, but. not for propylene) provide informationabout the action of inhibitor^.^, 447 50 It is inferred that propylene, whencompared with nitric oxide, combines more readily with CH, than withlarger radicals, such as CH2*O*C,H5 or CH,*CO*CH,.Recent work upon thermal decompositions, not mentioned in the pub-lications of SchumacherThe decomposition of di-tert.-alkyl peroxides 57 in the vapour phasefollows the mechanismand of SteacieY2 includes the following.CMe,*O*O*CMe, --+ 2COMe,COMe, -+ COMe, + CH,CH, + CH, = C2H6The kinetics have been investigated .58 At 140-160", the decompositionof di-tert.-butyl peroxide is a first-order homogeneous reaction. The rateof decomposition is not reduced (as judged from flow experiments) bypropylene or nitric oxide, although, as mentioned above, the latter combineswith methyl radicals formed in the second stage of the reaction. There isno chain reaction. The energy of activation is 39-1 kcals. The 0-0 bond49 D. A. Frank-Kamenetsky, Acta Physicochem.U.R.X.S., 1943, 18, 148; E. A.Blumberg and D. A. Frank-Kamenetsky, J. Physical Chem. Russia, 1948, 22, 171.50 L. S. Echols and R. N. Pease, J. Amer. Chem. SOC., 1939, 01, 1024.51 S. J. Magram and H. A. Taylor, J. Ghem. Physics, 1941, 9, 755.Ga H. A. Taylor and H. Bender, ibid., p. 761.53 E. W. R. Steacie and G. T. Shaw, ibid., 1935, 3, 344.64 H. A. Taylor and C: Tanford, ibid., 1944, 12, 47.5 5 J. S. A. Forsyth, Trans. Faraday SOC., 1941, 37, 312.56 J. E. Hobbs, Proc. Roy. SOC., 1938, A, 167, 456.5 7 Cf. N. A. Milas and D. M. Surgenor, J. Amer. Chem. SOC., 1946, 68, 205, 643;68 R. H. Raley, F. F. Rust, and W. E. Vaughan, J. Amer. Chem. SOC., 1948, 70, 88,P. George and A. D. Walsh, Trans. Faraday Xoc., 1946, 42, 94.2767; F.F. Rust, F. H. Seubold, and W. E. Vaughan, ibid., p. 9560 GENERAL AND PHYSICAL CHEMISTRY.energy in the peroxide is calculated to be 39 kcals. so the rate-determiningstep is taken to be unimolecular fission a t the 0-0 bond. The frequencyfactor of the Arrhenius equation has the high value of 3.2 x 1016.58a Thepyrolysis of di-tert. -amyl peroxide is approximately first order, the activ-ation energy for the initial step being 3 7 4 1 kcals. The inclusion of addedcompounds (e.g., hydrocarbons) with the decomposing peroxides is a valu-able means of studying the interactions of free radicals with those com-pounds. For instance, the vapour-phase addition of hydrogen chloride toethylene, by a free-radical mechanism, may be induced by di-tert.-butylperoxide.First order has been assigned to the decompositions of glyoxal tetra-acetate,59 isopropyl formate,60 tert.-butyl acetate and propionate,60" iso-propyl chlorocarbonateY6l digermane,62 and tetramethyltin (no inhibitionof primary process by nitric oxide).63 The dehydrochlorinations of 1 : 2-dichloroethane, ethyl chloride, and 1 : l-dichloroethane 63a are of first order.The first of these (retarded by propene and by n-hexane) has a free-radicalchain mechanism; the two latter appear to be genuine unimoleculardecompositions.Order 1.5 is ascribed to the decompositions of trimethylaluminium 64and tetrahydrofuran (nitric oxide does not inhibit,, but catalyses when inlarge amount ; so does propylene) .G5Morerecent work includes the following : (1) the decomposition of n-heptane 66by a flow method (first order, using kinetic equations of H.M. H u l b ~ r t ) , ~ ~giving products in agreement with the theories of F. 0. Rice; and of iso-butane 67a (some retardation by propylene) ; (2) the decomposition ofcyclohexene, cyclohexane, methylcyclopentane, and cyclopentane 68 (alluninfluenced by nitric oxide; rate-determining steps, first order), and ofcyclopentene 68a (no inhibition by nitric oxide) ; (3) the demonstration 419 6958n For a suggestion about high-frequency factors, see M. Szwarc, J. Chem. Physics,1949, 17, 107.59 J. C. Arnell, J. R. Dacey, and C. C. C o f i , Canadian J . Res., 1940, B, 18, 410.6O R. B. Anderson and H. H. Rowley, J . Physical Chem., 1943, 4'7, 454.6 1 A.R. Choppin and E. L. Compere, J . Amer. Chem. Soc., 1948, 70, 3797.62 H. J. Emelbus and H. H. G. Jellinek, Trans. Faraday Soc., 1944, 40, 93.63 C. E. Waring and W. S. Horton, J . Amer. Chem. SOC., 1945, 67, 540.630 D. H. R. Barton, J., 1949,148; D. H. R. BartonandK. E. Howlett, ibid., 155, 165.64 L. M. Yeddanapalli and C. C. Schubert, J . Chem. Physics, 1946, 14, 1.6 5 C. H. Klute and W. D. Walters, J . Amer. Chem. SOC., 1946, 68, 506.66 W. G. Appleby, W. H. Avery, and W. K. Meerbott, J . Amer. Chem. SOC., 1947,6 7 Id. Eng. Chem., 1944, 36, 1012.67a A. D. Stepukhovich, J . @en. Chem. Russia, 1945, 15, 341.68 L. Kuchler, Trans. Faraday SOC., 1939, 35, 874; 2. physikal. Chem., 1943, B, 63,307 ; G. R. Schultze and G. Wassermann, 2. Elektrochem., 1941,47, 774.6 8 0 D.W. Vanas and W. D. Waiters, J . Amer. Ckem. SOC., 1948, '70, 4035.69 C. N. Hinshelwood, Faraday Society Discussion, 1947, 2, 1 1 1 ; R. G. Partington,The pyrolysis of hydrocarbons is dealt with, in detail, by Steacie.2.E. Warrick and P. Fugassi, ibid., 1948, 52, 357, 1314.69, 2279.ibid., p. 114WILLIAMS AND SINGER: CHEMICAL KINETIOS. 61that the rates of the chain-inhibited decompositions of saturated paraffinsare almost independent of molecular size and shape for molecules largerthan propane (in contrast to oxidation rates); (5) the unimolecular fissionof toluene to form a hydrogen atom and a benzyl radical, and correspondingreactions for xylenes and the picolines, yielding information about bondstrengths and resonance energies of radicals; 70 (6) the application of theniass-spectrometer 7l to the study of intermediates formed in the decom-position of hydrocarbons.Theory of unirnoZecuZar processes. .A uninioleculnr reaction may beconsidered to consist of the following three steps :A = A * A * + - $ A f - + B + C(1.) (11.) (111.)Step (I) represents the acquisition of (at least) a critical amount of energyby the molecule (sometimes referred to as ( ( energisation ”), (11) the localis-ation of the critical energy in a particular bond (activation), and (111) theactual dissociation.Some attempts have been made in the period under review to obtaina better understanding of these individual steps.Either step (11) (case 1)or step (111) (case 2) may be rate-determining; and in step (11) the prob-ability of activation of an “energised ” molecule may have a constantvalue, independent of the excess of energy over the critical amount, or itmay be equal to the (statistical) probability that (at least) the criticalamount of energy is concentrated in one oscillator, while the remainder ofthe energy is shared among the other oscillators of the molecule (0.K. Riceand H. C. Ramsperger ; 72 L. 8. Kassel 73). If. G. Evans and G. S. Rush-brooke 74 have shown that both for case 1 and for case 2-the validity ofthe second hypothesis being assumed-the rate constant can be expectedto be of the order of e- Eo/kT; the distinction between case 1 and case 2is thus not a useful one. On the other hand, D. D. Eley 75 has suggestedthat such a distinction could be made by determining whether the temper-ature coefficient of the activation energy is positive or negative.Comparing Kassel’s treatment with the transition state method, Evansand Rushbrooke ascribe the discrepancy between the two to the fact thata dissociating bond does not vibrate harmonically (as assumed by Kassel)and that, consequently, the entropy of activation for this model is too low ;the two methods are equivalent if allowance is made for this factor.R.M. Barrer 76 has investigated the mechanism of step (11) for anidealised model : the molecule is considered to consist of a number ofharmonic oscillators of equal frequency, which can exchange energy quantaby “ vibrational collisions.” Making special assumptions concerning theprobability for the transfer of quanta between oscillators, it is possible to70 M.Szwarc, Faraday Society Discussion, 1947, 2, 39 ; J . Chena. Physics, 1948, 16,128 ; J. S. Roberts and M. Szwarc, ibid., p. 981.G. C. Eltenton, ibid., 1947, 15, 455. 72 J . Amer. Chem. SOC., 1927, 49, 1617.74 Trans. Faraday Soc., 1945, 41, 621.76 Ibid., 1948, 44, 399.73 J . Phy8icccZ Chem., 1928, 32, 225.7 K Ibid., 1943, 89, 16862 QBNERAL AND PHYSIOAL CHEMISTRY.calculate how much time will elapse before a given initial energy distributioiiis replaced by one in which a critical number of quanta is accumulated inthe “ breakable ) ) oscillator. The rather cumbersome calculations lead tothe result that the relatively greatest contribution to the reaction ratecomes from molecules whose energy considerably exceeds the critical amount.A more powerful method has been applied to the calculation of thefirst-order rate constant by N. €3.Slater.” If dissociation occurs when theextension of a bond is greater than qo, the absolute rate can be calculatedby finding the frequency with which the normal vibrations of the moleculewill combine in such a way as to make the extension of the bond (a,) greaterthan qo.According to the theory of small vibrationsQ, 5 F(t) = CcxSdg cos 2x (vst + #,)Swhere v, is the 8th normal frequency and t,hs the corresponding phase angle.The activation energy E, is the smallest value of the sum ’CE~ = E for whichthe condition Xlaslss = qo can be fulfilled.This turns out to be E, =B/2B1, . qo2, where B is the determinant llbrsll and B,, the cofactor of bllformed from the coefficients of the expression for the potential energy in9Sterms of “ internal )’ (e.g., stretching and bending) co-ordinates, V =tc %sq,qs.r . sTo obtain the rate constant? i t is necessary to calculate the averagefrequency of attainment of the critical extension for any particular dis-tribution of energy ( E ~ , E ~ , . . ., E ~ ) over the n modes of the molecule andthen to average over all possible values of E ~ , c2, . . ., E, (assuming thermo-dynamic equilibrium). The result for the rate constant is k = v . e-Eb/RT;v is of the order of 1013 sec.-l and can be expressed explicitly as v =1 ~ 2 / A , , B / A B , , , where B,, and B have the same meaning as above, andA,, and A are defined in an analogous manner by means of the coefficientsa,, of the expression for the kinetic energy &CZa,,q,q,.An alternativeformula for v is (v1v2 . . . vn)/(v2’v3’ . . . v n ’ ) ; v,, v2 are the normal fre-quencies, v2’, etc., the normal frequencies of the system when q1 has thefixed value qo.A particularly simple case arises when the potential energy of the dis-sociating bond is independent of the potential energy of the rest of themolecule : V becomes &(b,,qI2 $- XgZb,q,q,), E, = bl,qo2 and v = 1/2x . dbll/m(m is the reduced mass of the two atoms sharing the breaking bond) : themolecule behaves like a diatomic one (with respect to decomposition).This result was also obtained some time ago by H.Pel~er,’~ who used asimilar but less general method.7 7 Proc. Camb. Phil. SOC., 1939, 35, 56; Nature, 1947, 159, 264; 160, 576; PTOC.Roy. Soc., 1948, A , 194, 112.78 2. Electrochem., 1933, 89, 608; Nature, 1947, 160, 676.7 WILLIAMS AND SINGER : CHEMICAL KINBTICS. 63Slater’s treatment can be translated into the formalism of the transition-state theory by writing k = v/dpo . F*’/F, where F is the partition functionof the molecule, F*’ the partition function of the molecule with the co-ordinate q1 between qo - dq, and qo, and 21 the average velocity along ql.Although accurate predictions can perhaps not be expected from amolecular model based on the approximation of classical harmonic oscil-lators, i t is a satisfactory feature of this theory that the frequency factor vis expressed in terms of experimentally accessible parameters (i.e., thecoefficients, ufs, b, which can be obtained from spectroscopic data).An interesting empirical correlation between the activation energy ofuniinolecular decomposition and the vibration frequency of the dissociatingbond has been found by P. Fugassi and E.Warri~k,’~ The formulaEaCt. = 2.858V(35-5 - 900.45. <IDe) (i is the observed wave-number of thebreaking bond, D, its’ dissociation energy obtained by adding the zero-point vibrational energy to the therinochemical bond energy) has beenapplied in all cases where the necessary data for the weakest bond of themolecule were available; as well as in other cases, where only tenbativeassignments of observed frequencies could be made.The agreementbetween calculated and observed activation energies is, on the whole, sur-prisingly good. The authors do not give a theoretical explanation for thevalidity of the formula, but they point out that the expression bears aclose resemblance to the Morse energy of an anharmonic oscillator :EL.ibr. = Nhv(n + 8 ) - (Nhv)2(n + 4)2/4D, with n = 35.The validity of this correlation would seem to lend support to Pelzer’s(and Slater’s) result that the activation energy depends on the force eon-stant of the breaking bond only-provided its potential energy be notcoupled with that of the rest of the molecule. It is, of course, only in thiscase that an observed frequency can be assigned to the particular bond.The established theories of chemical kinetics contain the hypothesisthat the activated molecules are in thermodynamic equilibrium with t,henormal molecules (in the absence of chain processes).Some attemptshave recently been made to provide a theory not dependent on this assump-tion. A chemical reaction can be considered as the passage of a repre-sentative point in phase space over a pcjtential barrier ; the analysis of thisproblem is analogous to that of a system of Brownian particles escapingby diffusion over an energy barrier (e.g., a repulsive potential) in a viscousmedium. H. A. Kramers,80 who has developed this argument by classicalmethods, has shown that for a wide range of conditions, though not for all,the equilibrium hypothesis for the transition state will yield approximatelycorrect results. B.J. Zwolinski and H. Eyring 81 have considered a chemicalreaction to be represented by the transitions between a number of quantumstates which may be divided into “ initial ’’ and “ final ’’ states. Thekinetic equations applicable to this system are the same as those of a set79 J . Physical Chem., 1942, 46, 630. 80 Physica, 1940, 7, 284.J . Arnw. Chem. SOC., 1947, 69, 270264 GENERAL AND PHYSICAL CHEMISTRY.of simultaneous reactions. Calculations made for an idealised model,numerical values being assumed for the transition probabilities, lead to theconclusion that the results of the transition-state theory are not veryinaccurate.J.0. Hirschfelder 82 considers that the activated state of a unimolecularreaction must be approached by a number of steps involving the acquisitionof not more than one energy quantum at a time. The discrepancy betweenthe concentration of activated molecules calculated for this case and theequilibrium concentration of activated molecules is not negligible (the ratiois 0.385), but the difference between the expected reaction rates is notvery great.Although this ( ( non-equilibrium '' treatment of chemical reactionswould appear to be superior to the '' equilibrium " theory from a logicalpoint of view, it cannot yet rival the latter in usefulfiess.Chain Reactions.G. B. Kistiakowsky and E. R. van Artsdalena3 have found that thethermal and photochemical brominations of methane proceed by the samemechanism as the bromination of hydrogen.The initial rate of the thermalreaction a t 570" K. is almost the same for both reactions.(4( I ) Br, --+ 2Br(2) Br + CH, -!&+ CH, +HBr(B.)(1) Br + CH, = CH,Br + HBr(2) CH,Br + Br, = CH,Br, + Brx-3 (3) cH3 + Br, + CH,Br + Br (3) CHzBr + HBr = CH,Br + Br(4) CH, + HBr(5) 2Br + M --% Br, + MCH, + ErThe mechanism (A) gives the rate law (first approximation for methylbromide as sole bromination product) :[ K = equilibrium constant for (l)] which is in agreement with observation.Oxygen inhibits the reaction. The activation energy for the photochemicalreaction (determined from the rates at 423", 453", and 483" K.) is 17.8 kcals. ;this is ascribed to reaction (2).The coefficient k,/k, is not independent oftemperature as in the hydrogen-bromine reaction. From the temperaturecoefficient of the hydrogen bromide inhibition, E, - E , - 2 kcals. (E,, E3are the activation energies for E , and k3, respectively).The bromination of methyl bromide 83 is 7-5-10 times faster than thatof methane; it is not inhibited by hydrogen bromide. The observedactivation energy of 15-6 kcals. is attributed to step (1) of the scheme (23).82 J . Chenz. Physics, 1948, 16, 22. Ibid., 1944, 12, 469WILLIAMS AND SMOEB : CHEMICAL KINETICS. 65Calculations carried out by means of a reasonable model for the transitionstate of (1) give a rate which is in excellent agreement with the observedone.Although only the photochemical bromination of ethane has beeninvestigated,s* it is probable-by analogy with methane-that, in this casetoo, the thermal reaction would follow the same mechanism.Here, how-ever, the constants of the Bodenstein-Lind expression show trends.The data obtained from the kinetic analysis of the bromination ofmethane 83 and ethane 84 have been used to calculate the bond strengthsof the C-H bonds as 102 and 98 kcals., respectively.Another reaction following this type of rate law is H, + (CN), = 2HCN 8 5a t 550-675". There is no trouble due to polperisation of (CN),, but thereaction is a t least partly heterogeneous below 650". Apart from an induc-tion period and failure a t low pressures, the equationdlHCpU'1- w 3 2 I [(CpU'),IP a ' dt - 1 + 0.25[HCN]/Z[(CN),]is obeyed approximately, while the constants for 1-5 order fall sharplywith time when the ratio [H,]/[(CN),] is high.The activation energy is73 kcals. The mechanism is exactly the same as for the hydrogen-brominereaction, if Br, is replaced by (CN),.The nitrogen-oxygen reaction. The oxidation of nitrogen introducedinto explosive mixtures has been investigated by J. Zeldovich.86 Theresults reported and the ingenious kinetic analysis relate to the interactionof nitrogen and oxygen in a system whose temperature is falling.From the yields of nitric oxide in the reaction products of differentexplosive mixtures of nitrogen, oxygen and some gaseous " fuel " thefollowing facts are established : (1) The yield of nitric oxide is stronglycorrelated with the concentration of nitrogen and the concentration ofoxygen remaining after the combustion of the fuel.(2) The nature of thefuel used (e.g., H,, CO, CH,, etc.) does not influence the amount of nitricoxide produced, except in so far as the reaction temperature is affected.(3) I n independent flow experiments analysis of samples taken at differentpoints in a rapid stream of burning gas shows that the exothermal combus-tion is virtually completed in see., before measurable amounts of nitricoxide are formed (the oxidation of nitrogen ceases after see.). (4) Theyield of nitric oxide is always smaller than the equilibrium concentrationa t the (calculated) highest temperature attained during the explosion.The nitrogen-oxygen reaction is reversible ; and the rate of decompos-ition of nitric oxide was determined by measuring the yield of NO in mixturesto which nitrogen dioxide had been added initially.Extrapolation of thedata on the rate of decomposition of nitrogen dioxide 87 into nitric oxide84 H. C. Andersen and E. R. Van Artsdalen, J . Chem. Phylsics, 1948, 16, 479.*' N. C. Robertson and R. N. Pease, J . Amer. Chem. Soc., 1942, 64, 1880.Acta Physicochim. U.R.S.S., 1946, 21, 577; cf. M. V. Polyakov, L. A. Kostyu-chenko, and D. S. Nosenko, J. Physical Chem. Russia, 1944,18, 115. *' M. Bodenstein and H. Ramstetter, 2. physilca2. Chem., 1922,100, 106.REP.-VOL. XLV. 66 QDINBRAL AND PHYSICAL CHEMISTRY.and oxygen shows that decomposition will be complete in less than 10-8 8ec.in the relevant; temperature range ; consequent'ly, the final concentrationof nitric oxide is greater or less than its initial concentration depending anthe amount of nitrogen dioxide added initially.The " critical " concen-tration of nitric oxide, defined as that which is not changed by the reaction,depends on the maximum temperature (TTrl) reached; if this is below2500" K. the '( critical " concentration is comparable to the equilibriumconcentration at T,; it is relatively much smaller a t higher temperatures.The approximate activation energy for the decomposition of nitric oxideis obtained as follows : if the reaction is reversible and bimaleculard[NO]/dt k'[N2][02] - k[NOJ2 . . . . . (1)At the '' critical " concentration of nitric oxide (denoted by { 11, k'[N,][O,] =k(N012, since d[NO]/dt = 6 (approximately). Making the simplifyingassumption that the reaction proceeds for r seconds a t T, and then stops,( 1 ) can be integrated : this gives kz as a function of the " critical " con-centration and of the final conoentration of nitric oxide.If kr is plottedagainst l/Tm a, fairly straight line is obtained (2O0O--29QOo K.), The activ-ation energy ( A ) determined in this manner is 82 f '10 kcals./mole. Theactivation energy for the formation of nitric oxide ( A ' ) equals A $- 2E,where E is the known heat of the reaction : A' = 82 f 10 + 2 x 21-4 =125 f 10 kcals.The remainder of the analysis is carried out with the aid of these resultsand some ingenious dimensional considerations.Let [NO],.denote the equilibrium concentration and k the rate constant€or decomposition a t the instantaneous temperature, and [NO], the equili-brium concentration and k, the rate constant a t Tm. The rate equationcan be writtend[NO]/dt = k[NO]i'- lc[N0I2 . . . . .It is supposed that k/km and [NO];/[NO], depend on the dimensionless timevariable t / ~ only (7 is as yet unspecified) ; k/k, = f1(t/.) ; and [NOIa/[NO], - f 2 ( t / r ) for all reactiod mixtures. Thus (2) becomesIt can be shown that (3) would hold €or all reactions of this type (carriedout in the same system) provided the cooling lawdT/dt = - aT2 or 1/T = l/Tm + at . . ' (4)is valid. This cooling law has in fact been verified by independent experi-ments. Substituting De- A for the rate constant k and Re- EIRT for thoequilibrium constant K = [NO]~/([N2][O2])+, one can eliminate fi and f2from (3), using (4) WILLIAMS AND SINGER : CHEMIOAL KINETICS.67where z can now be identified with &/(A Jr 2E)a - R/6Ea (since A - 4E).Equation (5) can be integrated by means of approximate methods. Thecurve thus obtained for the variation of [NO]/[NO], with T, is very similarto the observed one ; the deviation of 12-13% for large yields is attributedto the inhomogeneity of the temperature distribution.Calculation of the cross-sectional area for the bimolecular reaction ofnitrogen and oxygen, however, gives a value about 1000 times too large( L e . , 3 x 10-13 The following chain mechanism has therefore beensuggested to the author by Semenov :k* .h.,kd k,(1) 0 + N, + 0, + N - 47 kcals.; (2) N + 0, + NO $- 0 + 4 kcals.k, /Ic3 and k,/k, may be calculated by statistical mechanics. Introducingthe calculated values for these, assuming equilibrium with respect to thedissociation of oxygen, and neglecting a term Tc,[NO] in a sum Ic,[NO] +E,[O,] (since [NO]<[O,]), the stationary state method gives :d[NO]/dt = 5 x 1011[02]-*. e-86>000/RT ([O,][N,] .2J . e- 439000/RT -- "012)1.-l mol. sec.-l . . . (6)This rate law differs from the bimolecular equation first assumed only bythe factor [O,]-*. Experiments designed to investigate the effect of theoxygen predsure over a wide range gave results in fair agreement with (6).The chain mechanism is compatible with reasonable cross-sectional areas forthe collisions.Branching-chain Reactions.The Hydrogen-Oxygen Reaction.-The general features of the thermalreaction between hydrogen and oxygen ar0 well known.88 At temperahresbetween 500" and 600" c., a very slow reaction at low pressures gives placeto an explosion a t the " first explosion limit " (pressure of a few mm.).At the '( second explosion limit " (about 100 mm.in a silica vessel a t 550"),explosion gives way to a reaction of measurable speed. The numericalvhlues of both limits vary with temperature ; and, on a pressure-temperaturegraph, the curves for the first and the second limit meet, forming a con-tinuous curve, bounded on the low-temperature side, which enclose8 aregion-referred to by some writers as the '' explosion peninsula "-inwhich explosion ocours.It is well established that the first limit occurswhere the concentrations of radicals formed in branching chains are nolonger kept stationary by surface deactivation, and that the second limitoccurs where a reaction in the gas phase prevents further effective branch-es C. N. Hinshelwood and A. T. Williamson, "The Reaction between Hydrogenand Oxygen," Oxford, 1934; N. Semenov, " Chemical Kinetics and Chain Reactions,"Oxford, 1935; B. Lewis and G. von Elbe, " Combustion, Flames and Explosions ofGases," Cambridge, 1938 ; W. Jost, " Exploaione und Verbrennungsvorgange in Gasen,"Berlin, 1939; L. 5. Kseeel, Ohem. Reviews, 1987, 21, 33168 QEENERAL AND PHYSICAL CHEMlSTR17'.ing of the chains.Above the second limit, the reaction is again controlledby deactivation of chain carriers a t the vessel wall. At still higher pres-sures, explosion again occurs. This can be due.to breakdown of isothermalconditions; but, even if isothermal conditions are maintained, a " thirdexplosion limit " is to be expected, on theoretical grounds, at which branch-ing of chains gets out of control. Evidence for a third limit has now beenobtained; and it appears that it is controlled by the extent to which chaincarriers are deactivated a t the surface.Recent work has made use of the observationby R. N. Pease 89 (in flow experiments) that the thermal combination ofhydrogen and oxygen is greatly retarded (up to 2000-fold) if the reactionvessel is rinsed, before use, with potassium chloride solution. I n Pease'sexperiments the rinsing also eliminated the formation of hydrogen peroxide,which otherwise appeared at 530-550" in the region of slow reaction.A. A.Frost and H. N. Al~ea,~O working with a Pyrex-glass vessel previouslyrinsed with a 10% potassium chloride solution, observed an increase in thefirst explosion limit of about 5-fold compared with earlier values in silicavessels. I n more recent. work, visible, coherent salt deposits have beenused; and their effect upon the first limit has been confirmed by A. H.Willbourn and C. N. Hinshelwood.loO Using various salts a t 500°, theseauthors have found increases in the first limit up to 18-f01d, as comparedwith an uncoated silica vessel.They find relative efficiencies to be Cs+,Kf > Ba++, Ca++ and I- > F-, Br-, SO,--, C1-, the effect of iodide beingparticularly marked. Clearly, the effects are due to much enhanced efficiencyof chain-breaking at the salt surfaces. Correspondingly, Willbourn andHinshelwood find the effect of the salts KCI, KI, CsCl, and CsI upon thesecond explosion limit to be very small, there being a slight depression, themore noticeable the higher the temperature. However, G. von Elbe andB. Lewisg9 find that the explosion region is diminished a t both its boun-daries by salt coatings, the second limit being appreciably lowered a t 500-530" by coating quartz or Pyrex vessels with the salts KC1, BaCL, Na2W04,and K,B,04. The same workers found that the salts KCl, BnCl,, Na2W04,and K2B40, reduced the rates of combination of hydrogen and oxygen, a tpressures above the second limit, to identical values; K2B,04 was lesseffective, except under conditions of rapid reaction; but K2B,0, + KOHbehaved like the other salts.A boric acid surface behaved like clean silicaor Pyrex. Von Elbe and Lewis drew the theoretically important con-clusion that limiting conditions had been reached where the chain-breakingefficiency of the surfaces had reached a constant maximum efficiency, so thatthe rate of chain destruction was governed by the rate of diffusion of chain-carriers to the wall. Willbourn and Hinshelwood made a similar assumptionin interpreting their own experiments in potassium chloride-coated vessels ;but they have pointed out that their assumption cannot be made withoutreserve, because caesium chloride (rate a t 550" = 0.28 mm./min.) retards@* A.A. Frost and H. N. Alyea, ibid., 1933, 55, 3227.Coated reaction vessels.J. Amer. Chem. SOC., 1930, 52, 5106WILLIAMS AND SINGER : CHEMICAL KINETICS. 69the reaction more eficiently than potassium chloride (rate = 0-60). Cullisand Hinshelwood loo find that iodide-coating completely alters the characterof the reaction, probably because of the liberation of minute amounts ofiodine, which is known to be an inhibitor of the hydrogen-oxygen reaction(cf. A. B. Nalbandyan 107). The efficient retarding salts have cationswhich can form hydrides; 100 and hydrogen atoms may be removed byreactions of the type KX + H = K + HX, ICX + H = KH + X.TheHO, radical might form H202 + H, the 'H being taken up as hydride andthe peroxide being decomposed on the salt surface (cf. Pease s9). On theother hand, von Elbe and Lewis99 have suggested that the chain-breakingefficiency of salt surfaces is due to strong adsorptive forces exerted bythem.The rupture of chains at surfaces has been treated mathematically byN. N. Semenovg2 and experimentally by A. B. Nalbandyan, in silver (ex-plosions observed, contrary to earlier work) and iron vessels 93 and on wiresof various material^,^^ and by W. V. Smith.95 Surfaces of ZnO,Cr,O, andgraphite are particularly effective in raising the first limit. In a vesselcoated with potassium tetraborate, containing a graphite rod, the energyof activation for H + 0, = OH + 0 is estimated to be 17.8 k ~ a l s .~ ~The practical importance of salt-coated vessels is that they make thereactions both slower and much more reproducible. The theoreticallyanticipated effects of vessel diameter and gas pressures upon the firstand the second explosion limits have been clearly observed in suchvessels.(In connection with surface effects, it is noteworthy that S. von Bogdandyand M. Polanyi 96 found an increased chain length in the hydrogen-chlorinereaction, induced by sodium atoms, when the vessel surface was coveredwith sodium chloride.)New investigations withsalt-coated vessels 97-100 have led to firm conclusions about the mechanismof reaction, with a substantial measure of agreement. The present positionof the reaction has been reviewed by C.N. Hinshelwood; lol and the estab-Mechanism of the hydrogen-oxygen reaction.92 Acta Physicochim. U.R.S.S., 1943, 18, 93.93 Compt. rend. Acad. Sci. U.R.S.S., 1941, 32, 196; 1944, 44, 328.94 Ibid., 1945, 47, 202; A. B. Nalbandyan and S. Shubina, J Physical Chem.Russia, 1946, 20, 1249; cf. V. V. Voevodsky, ibid., p. 779.9 5 J . Chem. Physics, 1943, 11, 110.9G 2. Electrochem., 1927, 33, 554.9 7 M. Prettre, J . Chim. physique, 1936, 33, 189.9 8 0. Oldenberg and H. S. Sommers, J . Chenz. Physics, 1939, 7, 279 ; 1940, 8, 468 ;1941, 9, 114, 573; 1942,10, 193; cf. F. S. Dainton, ibid., 1941, 9, 826; Trans. ParadaySoc., 1942, 38, 227.9B G. von Elbe and B. Lewis, J . Chem.Physics, 1939, 7, 710; H. R. HeiPle andB. Lewis, ibid., 1941, 9, 584; von Elbe and Lewis, ibid., 1942, 10, 366.A. H. Willbourn and C. N. Hinshelwood, Proc. Roy. SOC., 1946, A , 185, 353,369, 376; C. F. Cullis and C. N. Hinshelwood, ibid., 186, 462, 469.lol C. N. Hinshelwood, ibid., 188, 170 GENERAL AND PHYSIUAL UEBMISTRY.lishment of a plausible mechanism has, in turn, given riae to new discussionsof the explosive reaction.lQ5 The mechanisms proposed are :Scheme I Scheme II(von Elbe and Lewis). (Willbourn and Hinshelwood).(Authors' numbering of reactions.)(i) H,O, + M = 20H + M Initiation -+ H or OH(1) OH + H2 = H20 + H(2) H + 0, = OH + 0(3) 0 + H2 = OH + H(6) H + 0, + M = HO, + M(1) OH + H2 = K20 + H( 2 ) H + 0, = OH + 0(3) 0 + H, = OH + H(4) H + 0, + M = HO, + M(6) HO, + H, = H20 + OH(11) H02 + H2 = H202 + H ( 5 ) HO, -+ *H20 (walls)or (7) HO, + H, = H,O, + HSurface3 H,O, + 0 (12) 2H02 --(5) -I- O, + H2°2 = H2° + '2 -I- OH and (8) H,O, = H20 + QO, (7) HO, + H202 = H20 + 0, + OHSurface (13) H20, ---+ H2O + +OzSurface(14) H, + 0, --+ H,O,Surface Surface H, 0, OH ----+- Destruction H, 0, OH -----+ DestructionAgreement is reached on the following points : (a) The principal potentialchain-propagating processes are the reactions numbered (l), (2), and (3)in both schemes. They would give rise to branching chains.( b ) At pres-sures up to the first limit, branching is controlled by surface deactivationof H, 0, and OH. (c) Control of branching is re-established at the secondlimit by the reaction labelled (I, 6) and (11, 4).Gaseous recombinationssuch as 2H + M = H, + M are inadmis~ible.~~ (d) The radical HO, isdestroyed at the wall [reactions (I, 12) or (11, S)], but it may also reactwith H, by reactions (I, 11) and (11, 6) [or I1 (7)], and one of these processesbecomes the principal chain carrier in the reaction a t measurable speedabove the second explosion limit. Competition between (11, 6) or (I, 11)and surface deactivation of HO, accounts for the influence of surface uponthe reaction above the second limit. Von Elbe and Lewis argue that, withuncoated surfaces of low chain-breaking efficiency, the lifetime of HO,should become large and reaction (I, 11) should become noticeable at pres-sures around the second limit.Consequently, the value of the secondlimit should be higher in uncoated than in salt-coated vessels, as, indeed,these authors find experimentally (compare previous section).In scheme (I), the condition for explosiona t the second limit reducea toThe second explosion limit.Ic,[M] = 2k2in which [M] = [Ha] + [O,] + [XI, X being an inert molecule.second limit : lo2At the[H,I+ kO,[O,l+ kCXI= K ' (1WILLIAMR68 AND SINGER : CHEMICAL KINETICS. 71In this equation Ice, = &z/Z~,; Ex = &/&, and &,, goa, BX are oon-stants proportional, with the simpler gases, to the collision numbers ofthe respective molecules with the " reaction complex," H-0,; ko, andbx(kH2 = 1) can be calculated from the kinetic theory of Theyhave also been determined experimentally, from measurements of thesecond explosion limit pressure, by von Elbe and Lewis (I), in potassiumchloride-coated Pyrex vessels, for different proportions of hydrogen andoxygen in the reaction mixture, with and without addition of inart gases,a t temperatures of 480-570"; and also by Willbourn and Hinshelwood (11)a t 550-580", for uncoated silica and €or potassium chloride-coated vessels.The results of the two investigations are compared in the following table :kx, c~c., = Zx/ZH, kx, obs.kx, obs.Gas, X. I. 11. I. 11. - 1.80 - He ......................... 1.600, ........................ 0.42 0.4 0.35 0.4" -0.325N, ........................ 0.46 0.45 0.43 0.39*-0.35HSO 0162 14.3 l l * O * -8.1 ........................0.6-0.9CO, ........................ 0.43 0.51 1.47 0.90* Uncoated silioa vessel at 550".The agreement in the quantitative interpretation of the second explosionlimit appears to be excellent, and it supports the postulated mechanism.Nevertheless, this mechanism is not a unique solution, though much themost plausible one.99The two sets of experiments concur in furnishing a value for kco, higherthan the theoretical one, and also a particularly high value for kEzO (cf.Nalbandyan,lo7 who finds 7cRn0 = 5-5 a t 450"). The latter is important,because steam is the reaction product. Even a small amount of watervapour markedly lowers the second limit pressure; 91 and von Elbe andLewis consider that this fact explains a number of earlier observationsupon the hydrogen-oxygen reaction.The formation of OH or H irl.the processes[(I, 6) and (I, 11) ; (11,4) and (II,6) or (II,7)] which continue the (stationary)chain reaction, a t pressures above the second limit, implies that, a t highenough pressures, increased concentrations of H and OH may again causea branchiiig-chaii explosion at third limit. In uncoated reaction vesselswith surfaces o f low chain-breaking efficiency, the branching-chain explosiona t the third limit is masked by thermal explosions; but, with the slowerreactions in potassium chloride-coated vessels, the third limit has beendetected and cliaracterisecl. It occurs a t pressures between 400 and1600 mm. a t temperatures between 550" and 610". Since the principalchain-breaking process, above the second limit, is the surface deactivationof KO, [(I, 12); (11, 5 ) ] , it may be predicted that explosion a t the thirdlimit should be favoured and the third limit pressure should be lowered,by increasing diameter of the reaction vessel.This effect has been veri-fied.989 99 Quantitatively, the influences of the proportions of hydrogenThe third explosion limit.lo2 G. H. Grant and C. N. Hinshelwood, Proc. Roy. SOC., 1933, A , 141, 2972 GENERAL AND PHYSICAL CHEMISTRY.and oxygen in the reaction mixture, and of added inert gases, upon thevalue of the third limit pressure, resolve themselves into the influence ofgas composition upon the rate of formation of the HO, radical in the gasphase (as they do a t the second explosion limit), together with the influenceof gas composition upon the rate of diffusion of HO, to the wall, and withthe effect of hydrogen proportion in reaction (11, 6).For the influence ofgas composition upon the rate of (11, 4), the constants derived to accountfor the effects of changing gas composition a t the second limit can also beused at the third limit. This procedure has been employed both by vonElbe and Lewis and by Willbourn and Hinshelwood. It involves theassumption, made in both investigations, that the chain-breaking efficiencyof the salt surface is so high that the rate of diffusion determines the rateof destruction of the chain carrier. The validity of this assumption hasalready been commented on.Taking the reaction mechanism to be composed of the steps (11, 1)-(11, 6), the rate of formation of steam is given by equation (3), below.loOThe condition for explosion is that the denominator in the expression onthe right-hand side of this equation should be zero ; i.e.,in which2E,/Ch,[lMl = E,/(E,[H,I + 4CE,[MI = k41([H21 + ~0,[0,1 + hXlXl>*Using relative diffusion coefficients Dx' -- DHz/DX, which can be derivedfrom the kinetic theory of gases, the condit-ion for explosion, a t a giventemperature, reduces toin which px = [X]/[H,], K is identical with the constant K in equation (l),and C is a constant which must be found from experiments on the thirdlimit itself.Willbourn and Hinshclwood have applied equation (2) to theirresults for the effects of hydrogen-oxygen proportion and of admixednitrogen, carbon dioxide, and water vapour upon the value of the thirdlimit pressure a t 586".They find that the constants which must be insertedin equation (2) to give the best fit between the theoretical and the experi-mental curves are not far removed from the theoretical constants and thosedetermined from measurements a.t the second limit, It is noteworthy thatthe experimental curve for the influence of 100 mm. of carbon dioxide uponthe third limit a t varying proportions of hydrogen to oxygen is quite differentin form from the corresponding curve for 100 mm. of nitrogen (nitrogenlowers the third limit pressure) ; and that the general theoretical equation (2)reproduces this difference in form when suitable constants are inserted.The form is governed by the value of Ex.More elaborate equations--corresponding to the more elaborate scheine(1)-have been successfully applied to the third limit by von Elbe andLewis.Por these, reference must be made to the original paper. ThesWlLLIAMS AND SINGER : CHEMICAL KINETICS. 73authors point out that values of the third limit pressure may be distortedby two contradictory factors, namely, a thermal influence in the very rapidreactions (just below the explosion limit, rates as high as 80-100 mm. ofwater per min. were observed), tending to displace the third limit to lowerpressures; and the formation of steam, which should raise the third limitfor the same reason that it depresses the second limit (high kH-,o).How-ever, in the experiments of Willbourn and Hinshelwood water vapour loweredthe third limit pressure. This result, accompanied by a reduction of theconstant C of equation (2), was ascribed to an effect of water upon thepotassium chloride-coated surface, reducing its chain-breaking efficiency.Von Elbe and Lewis state that the third limit pressure is independentof the nature of the surface, if it is heavily coated with any of the saltsused by them. They find that the third limit explosion is preceded by aninduction period, during which a rapid reaction occurs. The inductionperiod (up to 70 seconds) is small near the junction of the second and thethird limits and increases towards lower temperatures.Nothing has so far been said about howthe chains are started.Von Elbe and Lewis reject the dissociation ofhydrogen into atoms as chain initiator, on the ground that the temperaturecoefficient of the reaction, in a range uninfluenced by explosion limits, givesan overall activation energy of the order of only 100 kcals., which theyhold to be insufficient to include the activation energies both of chain con-tinuation and of chain initiation, if the latter is the dissociation of hydrogenmolecules. Instead, they suggest that a spontaneous reaction (hetero-geneous or gaseous) in the first brief stage preceding the establishment ofstationary concentrations supplies atoms which react by the processes(I, S), (I, 12), and (I, 11) to form hydrogen peroxide. They summarisethis stage by the equationThe chain-initiation process.(11, 14) H, + 0, = H,O, (possibly a t surface)and they consider that the steady-state initiation reaction is(i) H,O, + M = M + H,O + 0 or 20Hmanner. Their reaction scheme (11) leads to the equationWillbourn and Hinshelwood 100 treat the initiation reaction in a novelin whichfi is the rate of the initiation reaction.A function R* is definedsuch that d[H,O] I dt = 2f1R*. With the expressions for Xk,[M] and for k,used in treating the experiments a t the third explosion limit, R* is givenby an expression involving the gas composition and the constants kx, Dx’,K , and C of equations (1) and (2)) already evaluated at the third limit. Thefunction R* can thus be calcubted, without reference to experiments on th74 GENERAL AND PHYSICJAL CHEMISTRY.rate of reaction.The rate of reaction is proportional to (f,R*), so thevariation of reaction rate with the pressures of hydrogen, oxygen, and inertgases can be calculated for different possible forms of the functionf,. Com-parison with the observed influence of these variables upon the rate shouldindicate the correct form off,.At the temperature of the experiments (>560") chain initiation in thegas phase is thought to be possible. Four processes are considered :( a ) H2 + 0, = 20H (c) H2 + 0 2 + H20, -++ 20H(b) H2 + M = 2H + M (d) H2-(Walls) -+ 2HOf these, reaction ( b ) , as chain initiator, gives much the best agreementbetween experiment and calculation. For this case, the function fl takesthe formf1 = E[H21(ZH~[H21 + z0~[021 +where ZHz, Zo2, and Zx are the relative collision numbers for hydrogenmolecules, respectively, with hydrogen, oxygen, and an inert gas X.TheZ values are calculated from kinetic theory.Cullis and Hinshelwood loo have measured rates of reaction a t differenttemperatures (560-596") and have calculated R* a t each temperature fromthird-limit data. They have thus obtained the temperature coefficient offl and are able to calculate, directly, the activation energy for the initiationreaction. They find this t80 be 100 kcals. for potassium chloride-coatedvessels and 92 kcals. for cEsium chloride-coated vessels. They regard theformer value as the more reliable and consider that the result supports theview that the dissociation of hydrogen into atoms is the initiation stepunder the conditions of their experiments.(Third-limit pressures arehigher for cesium than for potassium chloride.) P. G. Ashmore and F. S.Dainton lo2a support this conclusion. They find 134 and 123 kcals. forthe activation energy of initiation at two different gas pressures.The measurable reaction between the second and the third explosion limits.The schemes (I) and (11) concur in attributing the major part in the con-tinuing reaction above the second limit to the steps (I, 6), (I, ll), and(I, 12) or (11, 4) with (11, 5) and (11, 6) or (11, 7). To preserve a steadyconcentration of hydrogen peroxide, von Elbe and Lewis introduce the steps(I, 7) and (I, 5), together with (I, 13) (because hydrogen peroxide is knownto decompose heterogeneously) .lo3 They have formulated equations forthe reaction velocity to correspond with scheme (I) and have tested themexperimentally with generally satisfactory results.In uncoated silica or Pyrex vessels, the reaction above the second limitshows auto-acceleration in its early stages, and is often not easily repro-ducible in speed.I n salt-coated vessels, the reactions are, as a rule, notauto-accelerated, but proceed a t a constant rate for an appreciable time.The rates are reproducible.102a Nature, 1946, 158, 416.lo3 Cf. R. C. Mackenzie and M. Ritchie, PTOC. Roy. Xoc., 1646, A, 185, 207WILLIAMS AND SINGER : CHEMICAL XINETICS. 75To account for the auto-acceleration, V. V. Voevodsky104 adds thereactian NO, + H,O = H,O, + OH to the scheme (I), with the suppositionthat it is an easier reaction than (I, 11).In uncoated vessels, the difficulty ofstep (I, 11) leads to an accumulation of HQ, radicals (calculated to attain apartial pressure of nearly 3 mm. near the beginning of the reaction) andcombination is slow. The small amounts of water formed enter easilyinto reaction with HO,, forming OH. The reaction accelerates and theconcentration of HO, falls.The reactionin this region has been discussed by N. N, Semenov.lo5 Explosion is pre-ceded by it period of auto-acceleration, during which, according to Semenov,Ap = Ce4t. The experiments of A. Kovalsky,lo6 at pressures near thefirst limit, confirmed this and gave values for $ a t different temperaturesand initial pressures.Adopting, for the reaction mechanism, the stepsH, + 0, = 20H, followed by (I, 1, 2, 3, 6), with wall deactivation of Hand HO,, Semenov 1°5 derives equations for the reaction rate, a t pressuresnot greatly exceeding the first limit pressure. On introducing experimentalresults for +, p l , and p , (the first and the second limit pressures), the equa-tions lead to quantitative deductions, which are in approximate agreementwith experiment. Approximate agreement is also obtained a t higher pres-sures (still between the first and second limits), though experiments are verydifficult here, because of thermal effects. Experiments of A. €3. Nal-bandyan lo7 (made with a sensitive membrane manometer, furnishing photo-graphic reoords) give induction periods of <0.1 to 0.4 see.(decreasingtowards the middle of the explosion region and increasing near the ex-plosion limits), whose values are in acoord with theoretical calculation.Neither the nature of the wall (in potassium chloride-coated and stainless-steel vessels), nor the presence of water vapour, influences the temper-ature dependence of the induction period inside the explosion peninsula,and of 4. Water therefore does not react chemically with the activecentres.Semenov's equations lo7a also furnish rates for individual steps in themechanism (see below), and an estimate cjf the concentration of hydrogenatoms present a t various stages of the explosive reaction. The remarkableconclusion is reached that for stoicheiometric mixtures a t initial pressurepo = 1*43p1, 2p1, and 4p1, 5, 15, and 40%, respectively, of the initialhydrogen is present as hydrogen atoms (cf.von33lbe and Lewis's 99 estimatesfor the partial pressure of hydrogen atoms during the slow reaction ; e.g.,a t 560", pR = 9-7 xExperimental support is put forward for the prevalence of high con-Io4 J . Physical Chem. Russia, 1946, 20, 1285.Io6 N. N. Semenov, Bull. Acad. Sci. U.R.S.S., C1. Soi. Chim., 1945, 210; Compt.rend. Acad. Sci. U.R.S.S., 1944,43, 342 ; 44, 62, 241.Io6 Physikal. 2. Sovietunion, 1932, 1, 595; 1933, 4, 723.Io7 Acta Physicochim. U.R.S.S., 1944, 19, 483, 497 ; 1945, 20, 31 ; cf. Kondratev,Compt. rend, Amd. Sci. U.R.S.S., 1945, 49, 116.Acta Physicochim.U.R.S.S., 1945, 20, 291.The expllosive reaction between the first and the second limits.mm. a t total pressure 170 mm.)76 GENERAL AND PHYSICAL CHEMISTRY.centrations of hydrogen atoms in mixtures reacting within the explosionpeninsula. In the first place, this rests on the estimation of OH-radicalconcentration by absorption spectroscopy.lo8 Estimates by L. I. Avramenkoand V. N. Kondratev 109 were shown by 0. Oldenberg and F. F. Rieketo need re-interpretation. Taking this into account, later work by Avra-menko 111 leads to the conclusion that in a hydrogen-oxygen flame, a ttotal pressure about 40 mm. (flame temperatures 900-1370"~.), the OH-radical concentration exceeds lo4 times the thermodynamic equilibriumvalue and is thus brought into being by the chemical reaction. On thesupposition that the partial pressure of OH radicals (pOH) may amount to0.1% of the initial oxygen pressure,lo52 112 it is deduced from the relativerates of the reactions ( b ) and (c), below, that (PH should be 40-200 timesp O H , which means that pH is 6 2 0 % of the initial hydrogen pressure, inapproximate agreement with the above theoretical estimate.(In mixturesundergoing slow reaction at about 1 atm. pressure and 550", 0. Oldenberg,E. G . Schneider, and H. S. Sommers 113 detected no OH radicals by absorp-tion spectroscopy and concluded that their concentration was less than oneradical in 300,000 molecules.)Kondratev 114 furnishes experimental evidence of a different kind. Athermocouple inside a thin quartz tube, coated with ZnO,Cr,O,, is exposedto the reaction mixture.The heak of recombination of hydrogen atomsupon this particularly efficient catalytic surface 943 95 is registered as atemperature difference AT between this thermocouple and a second, un-coated, thermocouple. (On a third, potassium chloride-coated thermo-couple AT = 0, showing that the temperature rise on ZnO,Cr,O, is notcaused by recombination of OH radicals; cf. Smith.95) A temperaturerise AT is observed only for mixtures a t pressures within the explosionpeninsula; and it is not due to surface interaction of molecular hydrogenand oxygen. Total pressures up to 5 mm. were used, a t temperatures of476-693". The maximum observed value for AT was 284", with totalpressure, p = 3.83 mm.From a consideration of the heat balance, theexpression AT = 1000pH/p is deduced theoretically, which would givepE = 1 mm. It is found experimentally that pHjpcxAT, when pH/p iscalculated from the kinetic expressions, with the proportionality constant3000, so that the theoretical expression gives the correct order of magnitudefor the hydrogen-atom concentration.lo* Cf. A. G. Gaydon, " Spectroscopy and Combustion Theory," 2nd edn., London,lo9 Acta Physicochim. U.R.S.S., 1937, 7, 567.110 J . Chem. Physics, 1938, 6, 439, 779; 1939, 7, 485.ll1 Acta Physicochirn. U.R.S.S., 1942, 17, 197.112 V. N. Kondratev, J . Physical Chem. Russia, 1946, 20, 1231 ; Cornpt. rend. Acad.113 Physical Rev., 1940, 58, 1121.114 V. N. Kondretev and E.I. Kondrateva, ibid., 1946, 51, 607 ; J . Physical Chent.Russia, 1946, 20, 1239; H. Kondrateva and V. N. Kondratev, Acta Physicochim.U.R.S.S., 1946, 21, 1, 629.1948, p. 115.Sci. U.R.S.S., 1944, 44, 20WILLIAMS AND SINGER : CHEMICAL KINETICS. 77Sir A. C. Egerton and G. J. Minkoff have detected considerableamounts of hydrogen peroxide in hydrogen-oxygen flames (at 30-40 mm.)directed against c?, surface held a t -180". Part of tho hydrogen peroxide isformed in the gas phase, and the mechanism H + 0, -+ H02* ; HO,* +H, = H,O, + H is suggested for its formation, an excited HO, radicalbeing produced in binary collision between H and 0,.The evidence for the existence of the HO, radical in the gas phase hasbeen reviewed by Minkoff,l16 who applies the " semi-empirical " transition-state method to the reaction H + 0, = HO + 0.The following estimates are derived bySemenov and his collaborators (units : 1.sec.-l) :Rates of elementary reactions.( a ) H, + 0, = 20H ;( b ) OH + H, = H,O + H ; k = 7 x 10-12T4e-10,0oo/I~~'(c) H + 0, = OH + 0 ; k = 6.4 x 10-12T)e- l*$OO/RT(d) 117 0 + H, = OH + H ; k: < 3 x 10-11Tbe- fh00"/RT= 2-46 x 10-12THe- 45,oooiR7'For (c), Nalbandyan and Shubina 94 find E = 17,800 cals. from observ-ations on the first limit, in agreement with observations on the secondlimit. Von Elbe and Lewis 99 give E = 45.5 and 17.0 kcals., respectively,for reactions ( a ) and (c).For recent work on the influence of nitrogen dioxide upon the hydrogen-oxygen reaction, see F.s. Dainton and R. G. W. Norrish 11* and A. R.Nalbandyan. 119The Hydrogen Sulphide-Oxygen Reaction.-The oxidation of hydrogensulphide 120 takes place according to the equation 2H,S + 30, = 2S0, + 2H,O.The kinetics of the reaction have been comprehensively investigated byN. M. Emanuel.121 Over a wide range of pressure and temperature oxidationproceeds a t a measurable speed. At sufficiently high pressures and tempera-tures thermal explosions occur. At low pressures and high temperatures,explosions occur between pressure limits. The reaction clearly shows thecharacteristics of branching chains.The phenomenon of the induction period has been ingeniously investi-gated.122 The experimental arrangement included three interconnected115 Proc.Roy. Xoc., 1947, A, 191, 145; cf. W. 13. Rodebush, C. R. Keizer, F. S.McKee, and J. V. Quaglino, J. Amer. Chem. Soc., 1947, 69, 538; E. J. Badin, ibid.,1948, 70, 3651.116 Faraday SOC. Discussion, 1947, 2, 151.11' P. Harteck and U. Kopsch, 2. physikal. Chem., 1931, B, 12, 327.Proc. Roy. SOC., 1940, A, 177, 445.llS J . Physical Chem. Russia, 1946, 20, 1283.120 Cf. L. Farkas, 2. Elektrochem., 1931,37, 670 ; H. W. Thompson and N. S. Kelland,J., 1931,1809; B. YakovlevandP. Shantsrovich, Acta Physicochim. U.R.S.S., 1937,6,71.121 J . Physical Chem. Russia, 1940, 14, 863; Acta Physicochim. U.R.S.S., 1944, 19,360.lZ2 N. M. Emanuel, J. Physical Chem. Russia, 1945, 19, 15; cf. Semenov, J. Chern.Physics, 1939, 7, 683; Semenov and Emanuel, Compt.rend. Acad. Sci. U.R.S.S., 1940,28, 21978 GENERAL AND PHYSICAL CHEMISTRY.cylindrical vessels, the " preparatory " vessel (l), the " intermediary "vessel ( R ) , and the " indicator " vessel (2). Mixtures of hydrogen sulphideand oxygen, generally a t an initial pressure (Po) of 100 mm. were assembledin vessel (1) (kept generally a t 270"). After a known time (t,) in vessel (l),the reaction mixture was transferred to vessel (2) (kept generally a t ahigher temperature, e.g., 300"), either directly or after a sojourn (t') in (a).Let rl" be the normal induction period for a reaction mixture with theinitial conditions prevailing in vessel (11, and T~~ that for the temperatureof vessel (2) and for a freshly prepared reaction mixture a t an initial pres-sure equal to that taken up by the experimental mixture when transferredto vessel (2).Then, forexample, with (1) a t 270" and with Po = 100 mm., T ~ " - 27 secs. Afterdirect transfer of reaction mixture from vessel (1) to vessel (2) (which wasat 300") the pressure (P) in (2) was 83 mm. In a series of experiments,it was then found that when t, = 7,' - 27 secs., 72 = 0, i.e., reaction in (2)proceeded immediately with kinetics corresponding to the new temperatureand pressure. Thus, active centres formed during the induction periodin (1) survive the transfer to (2). With t, < 7," then 22 < T ~ " and T~ issmaller the nearer t, is to 7," ; r2 approaches 720 as t, _L, 0, corresponding tothe immediate transfer from (1) to (2) of an " unprepared " reaction mixture.The behaviour of the active centre was examined quantitatively bymaking use of the intermediary vessel (R).After a preparatory period oft, < T ~ " in vessel (l), the mixture was kept for time t' in R, a t room tem-perature. On connection with the indicator vessel (Z), the pressure in thelatter was approx. 50 mm., corresponding to - 60 secs. I n these cir-cumstanoes the observed induction period 22 in vessel (2) was a linearfunction of t,. This result is in accord with Semenov's theory; for (withq = fractional pressure change) in (1) q = Ale+ltl and, after transfer to (2)at time t,, q = A2e+*tz. Assuming no change during transfer, Aleditl =Let the observed induction period in (2) be T~.A2e+pt3 and T~ = 41t1/42 + ( 1 / ~ $ ~ ) In A,/A2.With t, = r,", and with vessel R a t different temperatures (always lessthan that requiied to bring about the oxidation of hydrogen sulphide), thelife of the active centre was found to be about 8 hours at room temperatureand about 8 mins. a t 135", as indicated by the observation r2 -+ rc20. At alltemperatures of R, r2 was a linear function oft', the period of sojourn in R.Defining the " relative concentration," c, of the active centre by puttingc = 1 for t, = T,O, the relation between T~ and c was determined, by trans-ferring a " prepared '' mixture to R after a time t, spent in (l), and thenreplacing a known fraction of the mixture in R by an " unprepared " onefrom (l), and measuring T ~ . The relation found is log c proportional to 72,which is itself linear with t,. This exponential growth of the active centrewith time is one of the first direct experimental proofs of Semenov's theory.The destruction of the active centre (SO, see below) in R is of firstorder, with an activation energy of 8-5 kcals./mole. Water vapour (andalso adjacent tap grease) accelerates its destruction. After a series ofexperiments a deposit of sulphur was found on the walls of RWILLIAMS AND SINGER : CHEMICAL KINETICS. 79Sulphur monoxide. The active centre has been identified as sulphurmonoxide, SO, pfeviously suggested by Semenov as an intermediate inthe oxidatiod of carbon disulphide and of carbon o ~ y s u l p h i d e , ~ ~ ~ anddetected spectroscopically 124 (along with CS) in a carbon disulphide flame.Sulphur monoxide was investigated particularly by P. W. S ~ h e n k , l ~ ~ whoprepared it by the action of an electric discharge upon a mixture of sulphurand sulphur dioxide vapours, and assigned to it bands in the spectral regionA 2490-3400~. Schenk found sulphur monoxide to be stable for a con-siderable time a t low pressure, then the characteristic bands vanished after48 hours, giving place to bands of sulphur dioxide. The decompositionwas written : 2SO f= SO, + S. In the gas phase, sulphur monoxide islargely present as the dimer S202.125, 126The spectrum of sulphur monoxide has been identified in a reactingmixture of hydi-ogen sulphide and 0 ~ y g e n . l ~ ~ In further experiments byN. M. Emanuel,122 the indicator vessel (2), of the previous apparatus, wasreplaced by an absorption tube for the spectroscopic observations. Thepartial pressure of sulphur monoxide, Pso, was estimated from the relativeintensities of the absorption bands, calibrated by measurement of thepressure of sulphur dioxide formed by decomposition of sulphur monoxide.The concentration of sulphur monoxide was found to grow during theinduction period. With a stoicheiometric mixture, Po = 100 mm. a t 270°,the maximum value of Pso was approx. 7-5 mm. a t an extent of conversion(as indicated by pressure change) of 3 = 0-18. The maximum rate ofreaction occurred a t 3 = 0.13. Thus, in the initial stage of the oxidationof hydrogen sulphide, up to 20% of the latter was converted into sulphurmonoxide. The spectroscopic measurements of Pso fell on the kineticcurve for increase in the concentration of the active centre.The decomposition of sulphur monoxide was followed spectroscopicallyin the intermediary vessel R a t various temperatures. The spectroscopicresults agreed with the previous kinetic results for the decay of the activecentre and gave an activation energy of 8 kcals. (cf. kinetic value). Theinteraction of sulphur monoxide (formed in the preparatory vessel) withwater, in the intermediary vessel, a t O---40°, was also examined spectro-scopically. The rate of reaction decreased with rising temperature andwas given by - dc/dt = kc3I2y, in which c and y are (dimensionless) relativeconcentrations of sulphur monoxide and water vapour respectively. Thereaction SO + S,02 + H,O = H2S + 2S0, was proposed in interpretationof the result.The identification of sulphur monoxide as the active centre was finally123 Cf. V. N. Kondratev, Acta Physicochim. U.R.S.X., 1942, 16, 272.12* Idem, 2. Physik, 1930, 63, 322.125 2. anorg. Chem., 1933, 211, 150; P. W. Schenk and H. Platz, ibid., 1935, 222,126 E. I. Kondrateva, and V. N. Kondratev, J. Physical Chern. Russia, 1940, 14,12’ N. M. Emanuel, D. S. Pavlov, and N. N. Semenov, Compt. rend. Acad. Sci.177.1528; V. G. Markovich and N. M. Emanuel, ibid., 1947, 21, 1251.U.R.S.S., 1940, 28, 618; Bull. Acad. Sci. U.R.S.S., C1. Sci. Chim., 1942, 9880 GENERAL AND PHYSICAL CHEMISTRY.confirmed by the introduction of synthetic sulphur monoxide 12* (made bythe method of Schenk) into stoicheiometric mixtures of hydrogen sulphideand oxygen. With various proportions of added sulphur monoxide (estim-ated spectroscopicalIy), the induction period was reduced to an extentwhich was in accord with the reduction caused by similar proportions ofthe active centre, formed in the preparatory vessel, as deduced from thekinetic experiments. The influence of synthetic sulphur monoxide uponthe induction period of the explosive reaction (see below) and upon thevalues of the explosion limits was also in satisfactory quantitative agree-ment with that deduced for the active centre formed in the preparatoryvessel. Synthetic sulphur monoxide enters into an explosive reaction with0 ~ y g e n . l ~ ~This has been studied 130 by arranging for thetransferred gas in the “ indicator ” vessel (e.g., a t 347”) to be a t pressures(e.g., 14 mm.) lying within the explosion peninsula, after sojourn in the“preparatory” vessel a t 270”, with Po = 100 mm. An induction periodnormally precedes explosion. It is again found that for t l < ~ l I , 7, forexplosion is a linear function of t,, approaching zero as t, + T~ . Witht, > explosion occurs in the “ indicator ” vessel without an inductionperiod, and will now take place a t pressures which lie outside the normalexplosion peninsula. For the increment AP, of the second limit pressurein the “ indicator ” vessel, it is ‘found that AP, = xPs0 and that Pso = @Po,where a and @ are constant a t a given temperature. These relations arenot observed a t the third (thermal) explosion limit.B’or the mechanism of the reaction, the following scheme is put forward(author’s numbering of equations) :A lower pressure limit has been observed.The explosive reaction.(0) H,S + 0, = H,O + SO + 44.4 kcals.(1) S + 0, = SO + 0 - 0-8 kcal.(2) 0 + H,S = H,O + S + 45-4 kcals.(3) SO + 0, = SO, + 0 + 20.4 kcals.(4) SO + SO + 0, = 2S0, + 158.4 kcals.S and 0 deactivated at wall.The step (4) is introduced because the maximum velocity occurs at anearly stage (at 18-20% conversion) of the reaction.lo5Emanuel l3l has studied the “ intermediates ” formed in chain reactionsby a novel “ contraction ” method. The reaction is arrested by expandingthe reaction mixture from the hot reaction vessel into a cold evacuatedvessel (or by removing the heat source, with subsequent rapid or slow128 N. M. Emanuel, Compt. rend. Acad. Sci. U.R.S.S., 1942,36, 145.129 H. Kondrateva and V. N. Kondratev, ibid., 1941, 31,. 128; E. Kondrateva andV. Kondratev, J. Physical Chem. Russia, 1941, 15, 731 ; 1944,18, 102.130 Emanuel, Compt. rend. Acad. Sci. U.R.S.S., 1942, 35, 250.131 Ibid., 1945, 48, 488; 1948, 59, 1137; V. G, Markovich and N, &I. Emanuel,J . Physical Chem. Russia, 1947, 21, 1259WILLIAMS AND SINGER : CHEMICAL KINETlCS. 81cooling). The contraction A (due to recombination of radical " inter-mediates " or sometimes to association of end products) is determined asthe difference between the pressure exerted in the cold vessel by the cooledreaction mixture and that exerted by dry air under the same conditions.Contractions have been observed during the oxidation of hydrogen sulphide,acetaldehyde, propylene, and acetylene. For hydrogen sulphide, A changesregularly as the reaction proceeds, going through a maximum a t 20% con-version. It is found that Acc[SO]; and that the dependence of A ontemperature of the reaction mixture agrees with the temperature effect of[SO], calculated from the influence of [SO] on the ignition limit.Additional papers on the mathematical theory of chain reactions arethose of N. N. S e r n e n ~ v , ~ ~ ~ A. A. Frank-Karnenetsk~,~~~ N. S. .Ak~lov,~~*and L. von MUffli11g.l3~K. S.G. W.F. S. DAINTON.G. S. HARTLEE-.K. SINGER.G. WILLIAMS.132 J . Physical Chenz. Russia, 1943,17, 187 ; Acta Physicochim.. U.R.S.S., 1943,18,93.133 Ibid., 1942, 16, 357.134 E.g., Compt. rend. Acad. Sci. U.R.S.S., 1945, 48, 644.13G 2. Physik, 1944, 122, 787

ISSN:0365-6217    

DOI:10.1039/AR9484500005

出版商:RSC    

年代:1948

数据来源: RSC

摘要:

INORGANIC CHEMISTRY.FOR some years past these Reports have taken the form of brief articleson special topics. The departure this year implies no criticism of thispolicy and is conditioned solely by the available material, which it is feltdemands a broad survey of the whole gamut of Inorganic Chemistry.Hence, after dealing with some general matters, this Report picks outwhat appears of most interest in a review based on the Periodic Table,for an English-language journalfor inorganic topics has so far gone unanswered, there have been never-theless welcome additions to the reference library of the inorganicamong them a second volumeY3 edited by W. C. Fernelius, of “ InorganicSyntheses,” and the first of seven projected volumes reviewing inorganicchemistry in Germany during the war years.The latter contains muchvaluable material, some of which has been referred to in these Reports,but also much which has not been previously published. For teachers,L. Pauling’s approach to first-year chemistry will be found stimulatingand inspiring.There is little need to point out the lack of order in inorganic nomen-clature, or to stress cuatom and prejudice as contributory causes. TheI.U.C. nomenclature committee issued no report after the London meetingin 1947 and the results of the forthcoming Amsterdam meeting are awaitedwith interest, Inadequacies in previous recommendations have beendiscussed by Ferneliuss and by (Miss) J. D. Scott and co-ordinationcompounds have been specifically examined.1° But of greater valueto those who seek to conform to prescribed practice is A.D. Mitchell’smonograph “ British Chemical Nomenclature.” l1 Here the assist-Though the plea in these ReportsAnn. Reports, 1944, 41, 87.2 R. W. G. Wyckoff, “ Crystal Structures,” Interscience, 1948; D. M. Yost andH. Russell, “ Systematic Inorganic Chemistry,” O.U.P., 1946 ; E. B. Maxted, “ ModernAdvances in Inorganic Chemistry,” O.U.P., 1947.3 “ Inorganic Syntheses,” Vol. 11, McGraw-Hill, 1946.4 W. H. Keesom, “ Helium,” Elsevier Publishing Co., 1942; J. Dement andH. C. Drake, “ Rarer Metals,” Chemical Publishing Co., N.Y., 1946; J. G. F. Druce,“ Rhenium,” C.U.P., 1948; D. M. Yost, H. Russell, and C. S. Garner, “ Rare EarthMetals and their Uses,” Chapman & Hall, 1947.FIAT Review of German Science (1939-1946), Inorganic Chemistry, Vol.I, 1948.“ General Chemistry,” W. H. Freeman, California, 1947. ’ We are indebted to Professor Bmsett for acquainting us with the position andproviding us with the draft of “ Inorganic Chemical Nomenclature,” being suggestionsput forward by himself and (the late) R. V. G. Ewens.W. C. Fernelius, Chem. Eng. News, 1948, 26, 161.Chern. Reviews, 1943, 32, 73, and ref. (3), Appendix, p. 257.lo W. C. Fernelius, E. M. Larson, L. E. March, and C. L. Rollinson, Chem. Ens,l1 “ British Chemical Nomenclature,” Edward Arnold, 1948.News, 1948, 26, 520DODD AND ROBINSON. 83ant editor of the Chemical Society, though not writing in an officialcapacity, sets out in a handy reference volume the conventions adoptedby the Journal, at the same time indicating other usages, notably thoserecommended in the I.U.C.(1940) rules and those adopted in ChemicaZAbstracts. Recommendations for the naming of oxy-acids, of peroxy-acids as distinct from per-acids, of iso- and hetero-polyacids, of the hydridesof boron, silicon, and the elements of Group IVB may be selected as oneswhere agreement is fairly general or where general adoption is likely tobe only a matter of time. On the other hand, the indication of variablemetallic valency in oxides, salts, and complex compounds is still underconsideration. The terminations - o m and -ic are obviously unsatisfactory-where an element exhibits more than two valencies, where the same termin-ation does not indicate the same numerical valency in two different metalg,and where, in some co-ordination compound^, the valency of the metal isby no means certain.It seems desirable to retain the Stock method ofindicating valency for single oxides and salts [Roman numerals in parenthesesafter the metal, e.g., lead(1V) oxide, PbO,; iron(I1,III) oxide, Fe,04;copper(1) chloride, CuCl]. The Stock method is applicable to co-ordin-ation compounds (hexacyanoferrate(I1) ion for [Fe(CN)J4-, molybdenum(II1)oxopent at hioc yanatomoly bdat e (TI) for Mo[Mo (CNS) 5O J 3) though open tothe same objection that the valency on the central atom is not alwaysknown. An alternative proposal due to (the late) R. V. G. Ewens is thatthe charge on the ion be placed in Arabic numerals in parentheses afterthe pame : thus, hexacyanoferrate( -4), and molybdenum( +3) oxopenta-thiocyanatomolybdate( - l), for the above examples.Without prejudice toany recommendations that may be made by the next I.U.C. Committeethe Ewens method has been used in this Report in conjunction with theStock method to give chemists an opportunity to assess their merits.For the remaining unnamed element 61, prometheurn, Pm, has beensuggested,12 supported by detailed evidence of priority. That manyinorganic chemists have seen their own version of the Periodic Table isevident from the number that have appeared,13 among them a furtherHelix Chemica,l* a plot of atomic mass against number of electrons inincomplete shells by T. Grj&bine,l5 and a less ambitious but very workablecontribution by T.S. Wheeler.lG The concept of chemical element hasbeen studied,17 and its development traced 18 from its earliest beginningsto our present knowledge of the isotopic nature of the elements. Isotopicalbundance rules have been examined 1 9 9 2o and attempts have been madel2 J. A. Marinsky and L. E. Glendenin, Chem. Eng. Mews, 1948, 26, 2346.l3 W. Finke, 2. Physik, 1944, 122, 230; P. C. Banerjee, J . Indian Chem. Xoc.,1945, 22, 130; Y. Ta, Ann. Physique, 1946, 1, 88.l4 J. Cueilleron, Compt. rend., 1946, 222, 742.l5 Bull. Xoc. chim., 1948, 473,l7 R. Hooykaas, Chem. WeeEblad, 1947, 43, 526.l8 N. Feather, Proc. Roy. Xoc. Edin., 1944-6, 62, 211.lo H. E. Suess, 2. Naturforsch., 1947, 2a, 311.2o F.C. Frank, Proc. Physical SOC., 1947, 60, 211.l6 Chem. and I d . , 1947, 42, 63884 INORGANIC CHEMISTRY.to correlate mass and charge regularities with P-activity, and relativeabundance with susceptibility to nuclear fission.18 The chemistry andphysics of isotopic indicators have been reviewed : 21 in this connectionreference to some particular&elements is made below. Questions of valencyand structural chemistry have received considerable attention in previousReports and elsewhere and have therefore been largely omitted this year,but reference must be made to reviews by Pauling of some of the problems 22and to his recent exposition 23 of the metallic bond. Among other mattersof general interest, the state and properties of metallic surfac~s,~4 partitionchromatography 25 in inorganic chemistry, and a list 26 of declassifiedatomic energy reports may be mentioned.There seems to be general agreement 27, 28, 29 that the stability of com-plexes of bivalent ions (with ammonia, ethylenediamine, propylenediamine,salicylaldehyde, salic ylaldeh yde - 5- sulphonate , 0 -form ylnapht hols, glycine,oxine) follows an order which is independent of the nature of the ligands :Pd > Cu > Ni > Pb > Co > Zn > Cd > Fe > Mn > Mgbut no simple relation exists between stability and covalent radii, andmuch remains to be learnt about chelate binding.I n continuation ofwork already reported 30 on the stability of copper chelate compounds,M. Calvin and R. H. Bailes 31 have studied the polarographic reduction of anumber of such complexes dissolved in 50% (by volume) aqueous pyridine.Most of the chelated copper(1) compounds were unstable and dissociatedto give the [Cu(C,H,N)]+ ion, though it was found, as might be expected,that the linking of co-ordinating groups together led to an increased stability.It has also been shown 32 that there is complete correlation between stabilityand the rate of exchange of copper chelate compounds with copper(I1)acetate in pyridine solution.The stability of complexes with the tridentatenitrilotriacetic acid, N(CH,*CO,H),, does, however, show 33 a decreasewith increasing radius where the central atoms are Li, Na, Ca, Sr, Ba. In21 P. Sue, J. C?him. p?hysique, 1941, 38, 31 ; G. dc Hevesy, Finska Kem.Medd., 1946,55, 55.22 Chem. Eng. News, 1947, 25, 2970, 3045; J . , 1948, 1461.23 Nature, 1948, 161, 1019; J . Arner. Chem. Soc., 1947, 69, 542; L. Pauling andF. J. Ewing, Rev. Mod. Physics, 1948, 20, 112.24 C. H. Desch, Nature, 1946, 157, 271.25 T. V. Arden, F. H. Burstall, G. R. Davies, J. A. Lewis, and R. P. Linstead,26 Nalure, 1947, 159, 411; 1947,160, 445; 1948, 161, 146; M. C. Leikend, Bulletin27 H. M. N. H. Irving and R. J. P. William, Nature, 1948, 162, 746.2s D. P. Mellor and L. Maley, ibid., 1947, 159, 370; 1948, 161, 436.2* M. Calvin and N. C. Melchior, J . Amer. Chem. Soc., 1948, 70, 3270, 3273.30 Ann. Reports, 1945, 42, 70.31 J . Arner. Chem. Soc., 1946, 68, 949.32 R. B. D a e l d and 31. Calvin, ibid., p. 557.33 G.Schwmzenbach, E. Kampitsch, and R. Steiner, Helv. CEm. Acta, 1945, 28,Nature, 1948, 162, 691.of Atomic Scientists, 1947, 127.828DODD AND ROBINSON. 85demonstration of formula (I) for dimethylglyoxime complexes F. Feigl andH. S. Suter 34 have prepared several salts of the acid (I), where M = I’d,and have shown that the acid gives no precipitate in the presence of nickelions. The inferred absence of free dimethylglyoxime indicates that (I) isa true inner complex and suggests that the complex, formerly written as(11), is in fact the ammonium salt of (I), where now M = Fe :0f\Fe,,, . . . . xNH3CH3-C=N< >N=C-CH, CH3-C=NCH3-C=Nfl \ g \N=(!+-CH3 CH3-k=Nf‘OH(11.) I 0 0I M0 0(1.)H2Other papers describe complex salts of ethanolamine with Th, Cr, Sn, Co,Cu, Ni,35 phenoxides involving Be, Al, Ti, Th, Zr,36 a dry method3‘ ofpreparation of metal ammine salts, and a method 38 using carbonyl or thionylchloride, for obtaining the anhydrous salts from hydrated Be, Al, Mg, Sr,Be, T1, Sn, CrIII, CuII, FeII, FeIII, Co, and Ni chlorides.Group 0.-Thirty-one natural gases containing more than one volume yoof helium have been examined 39 as likely profitable sources, and E.Gluckaufand F. A. Paneth40 have measured the helium content of the atmosphereup to 25 km., finding no variation greater than 0.2yo a t heights less than20 km. No evidence for gravitational separation of the constituents ofthe atmosphere is afforded. A recent conference4I on liquid helium hasdisclosed more manifestations of anomalous transport properties and anew kinetic theory thereby required.Superfluidity provides a new method 42for separating helium isotopes of mass 3 and 4. Mass-spectrograph beamsof neon ions can be absorbed 43 on silver discs up to some 2 pg. ern.-, toprovide convenient samples of spectroscopically clean “ monotopic ” neon.The pure isotope is released by heating the metals in a vacuum. Kryptonand xenon have been examined 44 for relative isotope abundance.Group 1.-The extension 45 of the Clusius-Dickel thermal diffusionmethod to the separation of ortho- and para-hydrogen is of great interestin that these species have identical molecular weight. A tube 1 m. long,34 J., 1948, 378.35 H. Britzinger and B. Hesse, 2. anorg.Chem., 1944, %2, 293.36 H. Funk and E. Rogler, ibid., p. 323.37 G. Jones and W. Juda, U.S. Pet., 2,412,890.38 H. Hecht, 2. anorg. Chem., 1947, 254, 37.39 F. P. Vajna, Bcinyhzati b Krihciszati Lapok, 1942, 75, 161.40 Proc. Roy. Soc., 1946, 185, A , 89.41 K. Mendelssohn, Xature, 1947, 160, 385.42 J. Franck, Physical Rev., 1946, 70, 561; J. G. Daunt, R. E. Probst, H. L. John-43 J. Koch, Nature, 1948, 161, 566.44 M. Lounsbury S. Epstein, and H. G. Thode, Physical Rev., 1947, 72, 517.46 K. Schafer and H. Corte, Naturm-ss., 1946, 33, 92.ston, L. T. Aldrich, and A. 0. Nier, ibid., 1947, 72, 50286 INORGANIU UHEMISTRY.cooled externally to 80"~. and furnished with a coaxial wire mainfaiaedat 220" K., gave an enrichment in p-H, of 4.8% at the lower end of thecolumn when the original mixture was the normal o-H, '76% and pH2 2SQ,(o.A factor of about 14 has been obtained 46 for protium-tritium separation a ta platinum cathode in 10% sodium hydroxide.The states of hydrogenabsorbed in, and desorbed from, palladium and other metals have beenin~estigated.~~ An interesting description 48 of the liquid-hydrogen planta t Oxford is available in the new journal Research. E. Wiberg49 hasreviewed German contributions to the chemistry of hydrides.Lithium has been compared 5O with magnesium in standard Grignardreactions. A comparative essay 51 on sodium and potassium brings outsmall differences in their properties. They have been used as active reduc-ing agents for halides of other metals, as witness the earliest manufactureof aluminium, and it now appears 52 &hat mixtures o f many fluorides,chlorides, bromides, and iodides with these metals may be detonated byshock. Evidence has been adduced 53 for the existence at 77" c .of unstable,and hitherto unreported, NaO,. A. HBrold 54 has measured the dissociationpressure of potassium hydride, and H. Guiter 55 has included lithium,sodium, and potassium carbonates in his extensive hydrolysis studiea. Asmall glass Castner-Kellner cell has been described 56 for the preparationof cesium and rubidium hydroxides. Four compounds CsB',nHF havebeenIts oxidation has beeninvestigated 58 by use of a thin deposited layer of radioactive, 64Cu, tracer,The formula CU[CU(OH)~] has been assigned 59 to copper(1) hydroxide anda similar structure to copper(1) salts.Copper polysulphide and polysulpha-salts have been investigated,60 and diamagnetic Cu,S, identified along withlower sulphides and salts K,Cu3SI, and KCuS4.describe four copper arsenates of which natural olivenite, 4Cu0,As,0,,H20,is richest in copper and the only one stable in water. The addition ofwhere n = 1, 2, 3, and 6.Copper has received considerable attention.H. Guerin and R. Mas46 M. L. Eidinoff, J. Amer. Chem. SOC., 1947, 69, 2507.47 J. BBnard and P. Albert, Compt. rend., 1947, 224, 45 ; A. Portevin, Metal Prog.,48 G. 0. Jones, A. H. Larsen, and F. E. Simon, Research, 1948, 1, 420.49 Ref. 5, p. 125.Z. W. Wicks, Interchem. Rev., 1946, 6, 69.61 H. N. Gilbert, Chem.Eng. News, 1948, 26, 2604.62 J. Cueilleron, Bull. SOC. chim., 1945, 12, 88.63 W. H. Schechter, H. H. Sisler, and J. Kleinberg, J. Amer. Chem. SOC., 1948, 70,64 Compt. rend., 1947, 224, 1826. 68 Bull. 800. chim., 1948, 16, 26, 29, 31.66 A. F. Winslow, H. A. Liebhsfsky, and H. M. Smith, J. Physical Coll. Chem.,67 R. Virginia Winsor and G. H. Cdy, J . Amer. Chem. SOC., 1948, 70, 1500.6* J. Bardeen, W. H. Brattain, and W. Shockley, J . Uhem. Physics, 1946, 14, 714.6o G. Peyronel and (Signa.) E. Pacilli, Gazzetta, 1946, 76, 265.61 Compt. rend., 1948, 226, 1616; $327, 973.1946, 50, 1206.267.1947, 51, 967.E. Csrrikre and A. Raynaud, Bull. SOC. chim., 1945, 12, 920DODD AND ROBINSON. 87sodium hydroxide to copper(I1) sulphate solutions results, according to pHmeasurements 62 and examination of precipitates, in two basie sulphates,4CuO,SO, and lOCuO,SO,, before the formation af CU(OH)~ ; the secondis not, however, observed if the pH measurement is made some 5 hoursa,fter adding the reagent.Similarly, 4CuO,N,O, or 5Cu0,N,05,5H,0 and3Cu0,CuC1,,H20 have been observed. From activity, conductivity, andother measurements on aqueous copper(I1) chloride, three types of solutionare re~ognised,~3 green [CuCl,]--, blue [CU(H,O),]+-~, and colourless Cu2C14.There are sharp transition points corresponding to the changeCu[CuCl,] + nH20 + [Cu(H,O),] t+ + [CuCl,]--and on further dilution to the colourless solution.The stabilities of dicarbonyl copper(1) chloride and bromide havc beenassessed 64 in terms of heat of formation, and a deduction from the Neriistequation has been made that, for stability, that quantity must be greaterthan 10.7 kcals.per mole of CO. Thus Cu2Br,,2C0 (10.0 kcals./CO mole)is unstable whereas Cu2C1,,2C0 (11.0) is stable up to 307" K. In a furtherattempt to prcparc copper carbonyl, H. Bloom 65 has passed carbon mon-oxide for several weeks over copper gauze kept at -550" in a glass tube.A substantial copper mirror in the 250-400" zone is ascribed, in the absenceof chlorine, to the formation and decomposition of copper carbonyl.P. Korosy,66 in decomposing copper(I1) formate at 200", has observed apartially volatile compound which deposits a copper mirror on hot glass. Asimilar phenomenon was observed with silver formate, but not with formatesof nickel, iron, cobalt, zinc, or cadmium or with copper oxalate or mes-oxalate.Bloom's mirror formation is thus likely to be due in some mannerto the presence of traces of hydrogen-containing compounds in the carbonmonoxide, The solution of carbon monoxide in aqueous ammoniaealcopper(1) chloride apparently consists 67 in physical solution, formation oftwo distinct complexes (one attacked by potassium cyanide, the other not),and oxidation to carbon dioxide by a process probably involving 2Cu+ +Cu++ + Cuo (metal) and 2Cu++ + CO + €120-+ 2Cu+ + 2H+ + CO,.Spectrographic investigation 68 of copper( I ) , silver, inercury( II), and potas-sium cyanides suggests that CuCN and AgCN exist as internal complexesand that it is this fact, rather than cyanihe-isocyanide isomerism, whichaccounts for the formation of carbylamine from copper (I) and silver cyanideswhereas those of potassium and mercury(I1) yield cyanides by alkylation.Acetates, 69 phenylacetates ,70 and ethylenediamine complexes of p yrophos -phates 71 have been studied.In connection with the latter, a formula of the62 E. CarriBre, H. Guiter, and E. Portal, Bull. SOC. chinz., 1946, 13, 396.63 C. Gomez Herrera, Anal. Pis. Quim., 1946, 42, 165.64 B. Ormont, Acta Physicochim. U.R.S.S., 1946, 21, 741.6 5 Nature, 1947, 159, 530.6 7 R. Duguet, Compt. rend., 1948, 226, 1527.6 8 F. Gallais, Bull. SOC. chim., 1945, 12, 657.69 (Mlle.) M. Gerbault, Compt. rend., 1946, 222, 292.7O M. Crawford, Nature, 1947, 160, 19.'l P.McCutcheon and S. Raymond, J. Amer. Chena. Soc., 1947, 69, 276.Ibid., 1947, 160, 2188 INORGANIC CHEMISTRY.type [Cu,2en][CuP,07] has been advanced on the basis of reactions with silvernitrate and potassium thiocyanate solutions. Compounds Cu2P207 ,2en,2H20(dark blue), Cu,P20,,3en,6H20 (lustrous blue plates, Cu2P2O7,4en,6H,O,and one copper-zinc compound CuZnP,O, ,2en,2H20 (both purple needles)are described. The last compound is prepared by adding zinc pyrophosphateto a solution of Cu2P,O7,4en,6H20. Presumably the suggested anionretains its identity in this mixed compound, in view of the similarity ofcolour. F. Gallais and J. P. Vives 72 have found that thermal decom-position of tetramminocopper( +2) nitrite does not lead to copper(I1) nitritebut to copper oxide and nitrate with the single possible intermediatediamminodinitrocopper. In aqueous solution hydrated copper(I1) nitriteexists as [Cu(NO,)(H,O),]+, and with excess of nitrite, [CU(NO,),(H,O)~]and [Cu(NO,),(H,O)]- may be present.Dissociation pressures of pyridino-copper( +2) perchlorate have been measured.', J. G. Breckenridge 74 hasprepared tridentate chelate complexes of copper(I1) and nickel(I1) involvingNH,-[CH,],*NH*[CH,],*NH, and OH-[CH,],*NH*[CH,],*NH,.Active silver oxides may be prepared 75 by the action of alkaline potassiumperoxydisulphate, K2S208, on silver nitrate solution in the presence ofbivalent manganese, copper, and cobalt nitrates. The washed precipitatecontains some base-metal oxide and is improved as an oxidant for carbonmonoxide by the presence of O-l-O.S~O of MnO, or CuO, or COO, of whichthe first gives the greatest increase in activity with the least decrease instability.Silver acetylidesof the form Ag2C,,AgN0, and Ag2C,,6AgNO, have been respectively pre-pared 76 directly from 10% and 25% silver nitrate solutions and have beencharacterised. The decomposition of single crystals of silver oxalate a t100-140" has been followed 77 by X-ray diffraction analysis, from whichit appears that the monoclinic structure is maintained until all the Ag2C204had disappeared. Part of the silver released assumed preferred orientations,the ratio of orientated to unorientated metal remaining constant throughoutthe decomposition. The gas evolution in both the photolytic and thethermal decomposition has also been measured 78 and correlated with thethree-dimensional growth of silver centres.Only two species, Ag2Cr04and Ag,Cr,O,, have been detected 79 in the three-component system Ag,O-Cr0,-H,O at 30". (In the same paper copper chromates are also men-tioned.)Gold is precipitated 80 quantitatively from trichloride solutions by theaction of hydrogen peroxide or sodium chlorite. Chlorine is evolved ifThe activated Ago is suitable for gas masks.7a Bull. SOC. chim., 1948, 15, 702.73 P. C. Sinha, and R. C. Ray, Trans. Faraday SOC., 1948, 44, 790.74 Canadian J . Res., 1948, 26B, 11.75 J. H. de Boer and J. van Ormondt, B.P. 579,809, 579,817.76 J. A. Shaw and E. Fisher, J . Amer. Chem.SOC., 1946, 68, 2745.7 7 R. L. Griffith, J . Chenz. Physics, 1946,14, 408.7 8 F. C. Tompkins, Trans. Faraday SOC., 1948, 44, 206.7O A. N. Campbell and H. P. Lemaire, Canadian J . Res., 1947, 25B, 243.so 0. Erllmetsii, Suomen Kern., 1942, 15B, 11DODD AND ROBINSON. 89platinum and allied metals are not precipitated.the isomorphism of hexachloroaurates( - 3), CS,M*~[AUC~,],, where MI1 --Cu, Zn, Hg, Cd (the cadmium compound being new), with compounds oftype Cs2AgAuC1, and C S ~ A U ~ A U ~ ~ ~ C ~ ~ , CsCdCl,, Cs2HgC1, ; the last twoshould therefore be formulated as Cs2M,C16. M. A. Peacock and R. M.Thompson 82 have described a new mineral, gold telluride Au2Te,.Group II.-Work on beryllium seems to be mainly confined to that ofH. N. Terem, who has applied the method of continuous differential weigh-ing to the dissociation of basic beryllium carbonate,s3 BeCO,$Be( OH),,3H20,of beryllium nitrate,s4 and of beryllium ~ u l p h a t e .~ ~ Activation energiesare given. The carbonate is apparently a mixture of BeCO, and Be(OH),and no evidence was found for a basic sulphate intermediate. The pre-paration of beryllium sulphide by the action of carbon disulphide vapourdiluted with nitrogen on heated beryllium oxide has been described.86and of mag-nesium sulphide has been shown to occur when acetylene, pentane, andhydrogen sulphide respectively are passed over heated magnesium.Anhydrous magnesium chloride results a9 from heating the hydrated chlorideor the oxide with ammonium chloride above 350".VQ. H. Hartfordg0has prepared MgCr,O,,SH,O as bright red-orange deliquescent crystalsfrom MgO and CrO, in water with pH adjusted to 2.8-3.0. At 95.4"the compound yields a monohydrate which is stable up to 300". A recentgeneral account 91 of the preparation and industrial applications of calciumhydride is available. Indication 92 that calcium tetroxide contains 0,-ions is gathered from the fact that preparations of calcium peroxide con-taining 5% of CaO, are paramagnetic. Chlorination 93 of dry calciumhydroxide yields Ca( OH)C1,H20, resistant to further attack. Slightlymoist material, in the cold, gives Ca(0H)Cl and Ca(OH)ClO,H,O, and, a t40", the optimum temperature, 2Ca( OH)Cl,Ca(ClO)Cl,Ca( OC1)2,3H,0, con-taining 41.3% of active C1.Further chlorination is prevented by theinertness of the basic chloride. The thermal decomposition 94 of calciumcarbonate is perfectly reversible and is the only reversible part of the decom-position 95 of dolomite. Both of biological and general interest is theX-Ray study has revealedThe formation of magnesium carbides, MgC, andA. Ferrari, R. Cecconi, and L. Cavalca, Gazzetta, 1943, 73, 23.82 Amer. Min., 1946, 31, 515.83 H. N. Terem, Compt. reid., 1946, 222, 1436; Rev. Pac. Sci. Istanbul, 1946, A , 11,84 I d e m , ibid., p . 99; Compt. rend., 1946, 222, 1387.8 6 A. ChrBtien and P. Silber, ibid., 1948, 226, 2072.87 F. Irmann and W. D-Treadwell, Helv. Chim. Acta, 1947, 30, 775.88 K. Nielsen, Ann. Chim., 1947, 2, 354.1 3 ~ J. G. N.Gaskin, J . SOC. Chem. Ind., 1946, 65, 215.107.s6 Idem, i b d . , p. 1347.W. H. Hartford, J. Amer. Chem. SOC., 1946, 68, 2192.E. E. Halls, Ind. Chem., 1946, 22, 680.92 P. Ehrlich, 2. anorg. Chem., 1944, 252, 270.93 L. ForsBn, Svensk Kem. Tidskr., 1941, 53, 217.94 L. Hackspill and (Mlle.) H. Ostertag, Compt. rend., 1948, 227, 1000.96 Y. Schwob, Compt. rend., 1947, 224, 4790 INORQANIU CHEMISTRY.observation 96 that phosphate increase8 the solubility of calcium carbonateand bicarbonate and that of normal calcium phosphate, through the form-ation of the complexes [Ca,(HPO,)(CO,)] and [Ca,(PO,)CO,]-, but that bi-carbonate does not correspondingly affect the solubility of magnesiumhydrogen phosphate. Camplex axalato- and aaetafo-calcium chloride havebeen prepared 98 and calcium aluminate 99 and tetracalcium aluminoferratehave been the subject of chemioal, X-ray, and magnetic investigation.Among the phases observed by X-ray study2 in the system BaC0,-Fe 0 , a perovskite-type phase Ba,Fe,O,, (iron valency 3.25) is observedwhich lacks three oxide ions per unit cell for ideal structure.The defectis associated with catalytic activity in the oxidation of carbon monoxide.Hard, clear, pale yellow crystals of barium titanium oxide have been pre-pared and the transition point between tetragonal and cubic structure(between 122" and 129') has been identified with the Curie point transitiontemperature (-125') between ferro- and non-ferro-electric structures. Theunusually high permittivity (ferroelectric) of the tetragonal variety af thisperovskite-type compound is associated with the ability of the Ti4+ ion to" rattle " within its octahedral cage of oxide ions.Strontium hexanitrito-cobaltate( -3), S~8[Co(N0,)6],,15H,0, has been prepared from the silversalt and strontium chloride : the method is not applicable to calcium andcadmium salts.Very pure zinc in 95% yield, free from ZnO, As, Ye, and Pb, can beobtained 7 by reducing zinc sulphide, oxide ar silicate with CaC2-stronglyexothermal reactions, commencing at 700--800", catalysed by sodiumchloride, which may be carried out in an atmosphere of steam or in a vacuum.The oxide of zinc has been found 8 to vaporise by way of Zn and O,, theheat of sublimation being 111-11245 kcals. /mole of ZnO.A temperatureof 1950" is required a t 760 mm. of zinc chloride andnitrate solutions on progressive dilution give evidence of [ZnX( OH),]-- andZnX(0H) as intermediate stages (X = C1 ar NO,). Zinc sulphate on dilutiongives Zn,SO,( OH), and [Zn(OH)(SO4),l3-. Hydrolysis of zinc chloride and7 : 3Hydrolysis studies96 I. Greenwald, J. Biol. Chem., 1945, lSl, 697.98 (Mlle.) M. Gerbault, Compt. rend., 1946, 223, 732.99 J. R. Goldsmith, J . Geol., 1948, 56, 80.V. Cirilli, Ric. Sci., 1947, 1'7, 439; J. Brocard, Compt. rend., 1946, 223s 900.M. Erchak, junr., I. Fmkuch, and R. Wwd, J . A w r . Chem. Xw., 1946, 6Q, 2085,H. F. Kay and R. G. Rhodes, Nature, 1947, 160, 126.(Miss) H. D. Megaw, Trans. Farack9 Sm., 1946, A , 42, 225; Proc. Physical SOC.,1946, 58, 133; D.F. Rushman and M. A. Strivem, Trans. Faraday Soc., 1946, A , 42,231; M. G. Hamood, P. Popper, and D. F. Rushman, Nature, 1947, 160, 58; J. K.H u h , ibid., p. 127.A. Ferrari and L. Cavaloa, Uwzetta, 1946, 76, 120.L. Hackspill and (Mlle.) M. L. JungBeiscb, Compt. read., 1946, 223, 181 ; (Mlle.)2093.M. L. Jungfleisch, ibid., p. 1003.* M. Pourbaix, Bull. SOC. chim. Belg., 1944, 53, 159.E. Cwihe, H. Guiter, and M. Anouax, B d l . XOC. china., 1946, 13, 405; 1947,14, 72DODD AND ROBINSON. 91zinc sulphate by sodium hydroxide, however, yields no evidence lo of theformation of basic salts of definite composition ; equilibrium is only reachedsome 48 hours after addition of reagent. Zinc acetates and acetato-chlorides have been studied.ll D.B. Cruickshank l2 has described somenew zinc ferro- and ferri-cyanide complexes where, in solutions containingZn++, K,Fe(CN),, and K I a t concentrations of 0~001-0-0001~, the zincacts preferentially as a link between ferro- and ferri-cyanide radicals.Singly-linked chains stable up to three units, doubly-linked up to five,appear to be formed along with branched chains, the maximum size ofany type of chain being about eight units.The conditions for the precipitation of cadmium hydroxide have beenstudied,13 and further papers l4 have appeared on the basic cadmiumsulphates. The thermal dissociation of cadmium iodide has been followed l5between 900" and 1200" by measurement of its absorption spectrum : thefollowing equilibria exist, CdI + Cd + I,, CdI, =+= CdI + I, andI, += I + I.Accurate measurements for the corresponding bromidewere prevented by the overlapping of the spectra of bromine and saltvapour.A detailed description l6 has been given of a ten-cell countercurrentreflux still used for concentrating mercury isotopes. Mercury(I1) sulphidehas been investigated by W. D. Treadwell and F. Schaufelberger,17 whofound the heat of formation to be -14 and -12.8 kcals. for cinnabar andmetacinnabar respectively. The thermodynamic solubility product cal-culated for the black sulphide is much less than the experimental value :to account €or this it is assumed that the acid H,[HgS,] is formed. Thehydrolysis of mercury(I1) chloride and bromide both on aqueous dilution l8and on addition of sodium or potassium hydrogen carbonate or sodiumpyrophosphate l9 has been studied.L. G. Sillen and G. Ingeldt 2o havereinvestigated the equilibria Hg++ + HgXe --+ 2HgX+ (X = C1, Br, I ) ,have detected complexes and ion pairs involved in mercury(1) and mer-cury(I1) nitrates and sulphates, and have measured their equilibrium con-stants. Red mercury(I1) chlorite, soluble in dilute acids, has been pre-pared 21 from carbonate-free sodium chlorite and mercury(I.1) nitrate (butlo S. de Mende, Compt. rend., 1948, 226, 916.l1 (Mlle.) M. Gerbault, ibid., 1946, 222, 1109.le Research, 1948, 1, 663.Is (Mlle.) M. Quintin, Compt. rend., 1945, 226, 910.l4 Ann. Reports, 1944, 41, 95; W. Feitknecht, Helv. Chirn. Acta, 1945, 28, 1444;W.Feitknecht and W. Gelber, ibid., p. 1454; B. C. Halder, J. I n d i a n Chem. SOC.,1946, 23, 147.l5 K. Wieland and A. Herczog, Helv. Chim. Acta, 1946, 29, 1702.1 7 Helv. Chim. Acta, 1946, 29, 1936.l8 E. Carribre and M. Lafitte, Bull. SOC. chim., 1945, 12, 533 ; E. Carrihre, H. Guiter,l9 J. Lmwe, Cornpt. rend., 1946, 22B, 1392.2o Svensk Kern. Tidskr., 1946, 58, 62, 61, 104.21 0. Eramet&, Suornelt Kern., 1942, 15, B, 11.A. K. Brewer and S. L. Madorsky, J. Res. Nut. Bur. Stand., 1947, 38, 129.rand M. Lafitte, ibid., 1948, 15, 23, 2592 ZNORGAXIC CHEMISTRY.not chloride), and various complex decomposition products of the chloritehave been described. T. D. O'Brien's work2, on some ethylenediamino-mercury(I1) complexes has demonstrated the existence of Hg en C1,(III), en(HgCl,), (IVa or IVb), Hg en,SO, and Hg en,(H,O),SO, (en =NH,*CH,*CH,*NH,).The compound (IV) is soluble in excess of ethylene-(111.) (IVa.) (IVb.)diamine reagent to form a complex which, from a break in the curve ofrefractive index against the ratio en : HgC1, at a value of 3 : 1 for thatratio, appears to be (Hg en,)Cl,. Evidence is thus given for 6-co-ordinatedmercury(I1) in that complex and presumably in Hg en,(H,O),SO,. Thepreparation of ethylmercury phosphates (HgEt),HPO,, (HgEt)H,PO,, and(HgEt),PO, has been described.23Group III.-Since the determination, by H. V. A. Briscoe and P. L.Robinson,24 of the atomic weight of boron, a mass-spectrographic deter-mination 25 of relative isotopic abundance has been needed to confirm thesmall differences in the ratio llB : loB which then seemed probable insamples from the various localities, e.g., California, Tuscany, and AsiaMinor.Such confirmation has now been obtained, and variations in theratio range from 4.416 -+ 0-004 (Tuscany) to 4.222 & 0.004 (Stassfurt).In two cases the earlier chemical atomic weights compare very favourablywith the mass spectrographic results :Mass-spectro-Source. graphic. Gravimetric,Tuscany ................................. 10.82 6 10-825Turkey ................................. 10.822 10.818................................ 10.840 California. { ::: :;: 1Possible variation in isotopic abundance over the various parts of theCalifornia *deposit has yet to be investigated, but better agreement withthe gravimetric value does not seem likely.Hydroborons have received extensive comment 26 recently and, for thepresent, only the important X-ray determination2' of the structure ofBI0Hl4 need be remarked.With reference to related compounds, E. Wiberghas reviewed28 wartime German work not only on the hydroborons, but22 J . Amer. Chem. SOC., 1948, 70, 2771.23 A. D. Ainley, L. A. Elson, and W. A. Sexton, J., 1946, 776.24 J., 1925, 696; 1927, 282.25 H. G. Thode, J. Macnamara, F. P. Lessing, and C. B. Collins, J. Anter. Chem.SOC., 1948, 'SO, 3008.26 Ann. Reports, 1947, 44, 52; Quart. Rewiews, 1948, 2, 132.2 7 - 5 . S. Kasper, C. M. Lucht, and D. Harker, J. Arner. Chem. SOC., 1948, '70, 881;28 Ref. 5, p. 126.G.Silbiger and S. H. Bauer, ibid., p. 115DODD AND ROBINSON. 93also on the range of compounds BH,*NH,, BH2:NH2, BHiNH and on awide variety of derivatives with substituents F, C1, Br, Me, Et, OH, NMe,,- .+ NHMe, Ph. The tendency of borazene (BHGNH,) derivatives to>B-N< dimerise, and of borazine (BHiNH) to trimerise to borazole deriv- I I atives, is shown 29 to depend on the extent to which substituents>N-B<+ - influence the resonance between > B d < and >B-fi<. (v') Dimerisation to (V) will be favoured by a larger contributionof the former canonical, and thus by substituents a t the boron atom inthe order C1 > Br > H > CH, > C,H, > NR,, and in the reverse ordera t the nitrogen atom.Borazole and derivatives 3O and boron nitride 31 are also considered byWiberg.There is some overlap with J. Goubeau's account,32 in the samevolume, of German work on boron halides, boron oxide, methyl esters ofboric acid, and trimethyl- and triethyl-boron and derivatives. The thermo-dynamic stability of the ethylaminotrimethylborons (BMe,,NH,Et,-,) hasbeen ~tudied.~3 Neither Wiberg and K. Hertwig 34 nor A. W. Laubengayerand G. F. Condike 35 have found any evidence for any compound formationbetween BF, and NH,, other than BF,,NH,. The latter authors haveprepared this substance in quantity and find it to be monomeric and un-dissociated in aqueous solution, with a heat of formation from gaseousammonia of 41.3 kcals./rnole a t 0". At 125" the compound dispropor-tionates thus, 4NH,,BF3 + 3NH,BF4 + BN, and vapour pressurevalues for heated NH3,BF, are in fact those for NH4BF,, the only volatiledecomposition product below 150".C. A. Wamser36 has shown fromconductivity measurements that the formation of tetrafluoboric acid isstepwise, as follows :3HF + HBO, -+ HBF,OH (immediate)HF + HBF,OH HBF, + H20 (slow to equilibrium)He and I. G Rys 37 have prepared KBF30H which is shown to be identicalwith the previously reported K,B2F,,1.5H20. D. R. Martin 38 has reviewedthe formation of co-ordination compounds of boron halides and shown thatthe boron atom weakens as an electron acceptor from BF, to BI,.Aluminium phosphide has been prepared39 as a black solid whichdissociates before melting. Mixed aqueous solutions of aluminium fluorideand sulphate give,40 on treatment with ammonia, compounds in the range29 E.Wiberg, A. Bolz, P. Buchheit, and K. Hertwig, J . Amer. Chem. SOC., 1948, '70,30 Ibid., p. 138.31 E. Wiberg and A. Bolz, Ber., 1940, 73, 209. 32 Ref. 5, p. 226.33 H. C. Brown and M. D. Taylor, J . Amer. CJhem. Soc., 1947, 69, 1332.34 Ref. 6, p. 217.35 J . Amer. Chem. Soc., 1948, 70, 2274. 36 Ibid., p. 1209.37 Compt. rend. Acad. Sci. U.R.S.S., 1946, 54, 325.38 J . Physical CoEl. Chem., 1947, 51, 1400; Chem. Reviews, 1948, 42, 581.39 E. Montignie, Bull. SOC. chim., 1946, 13, 276.40 J. M. Cowley and T. R. Scott, J . Amer. Chern. SOC., 1948, 70, 105.13394 INORGANIC CRBIMISTRY.AlF(OH), to AlF,(QH). X-Ray study shows that these, on heating,decompose directly into AlF, and Al(OH),, with no evidence for AlOF.Raman spectra of molten AlCl,,NH, indicate l1 that the additive com-pound involves AlCl, and not AI,Cl,.The hydrolysis of aluminium chloridehas been found 42 to yield first H,[AlCl,(OH),] and then a t greater dilutionH,[AlCI,(OH),] ; the sulphate gives H[Al(SO,)(OH),]. There is evidence 43that the precipitation of alumina from sodium aluminate solutions bycarbon dioxide a t 60" proceeds according to 2A10,- + 2H,O+ -+A120,,2H,0.There appears to be nothing to add to the reportedu chemistry ofgallium, but the chemistry of indium has received attention in a series ofpapers by T. Moeller concerned with the hydrolysis of indium halide45and the precipitation of the hydroxidef6 an organic precipitant for indium,47and the formation of indates 48 and oxalato-indates.49 F.Ensslin andS. Valentiner have also prepared a number of indates by fusion ofIn(N03)3 with various metal nitrates. Ensslin and 0. Lessmann 51 haveplotted the system In,03-SO3-H,O a t Z O O , 40°, and 60" and have measuredthe solubility of indium trihalides in non-aqueous solvents.Thallium sulphate treated with ammonium hydroxide and hydrogensulphide a t 50" under nitrogen gives 52 thallium sulphide. On admittingoxygen, a moderate reaction occurs, catalysed by water vapour, and blackT1,S gives way to olive-brown or-TI,SO,. Though this compound is stablein air at room temperature it changes slowly into greenish-yellow p-TI,SO,when heated in a vacuum to 250".Chemically, both forms are thallium(1)sulphoxylate, though X-ray study shows them to be of different structure,the first of which has not been previously reported : both forms differ fromT1,S. Though thallium has hitherto been regarded as having little tendencyto form with organic acids normal and inner complexes insoluble in water,F. Feigl 53 has prepared stable inner complex salts of thallium(II1) withsuch agents as nitrosonaphthylhydroxylamine and 8-hydroxyquinoline.Thsllium(1) ferrate(III), T1Fe02, has been described.=Group IV.-Bands have been 0bserved5~ in the spectra of cometJs attribut-able to the molecules 12C13C and 13C13C. The relative abundance of 13C41 J. Goubeau and H. Siebert, 2. anorg, Chem., 1947, 254, 126.4a E. CarriBre and P.Faure, Bull. SOC. chim., 1942, 9, 809; M. Le Peintre, Cornpt.43 K. L. Elmore, C. M. Mason, and J. D. Hatfield, J . Amer. Chem. Xoc., 1945,67, 1449.44 Ann. Reports, 1944, 41, 102.46 J . Amer. Chem. Soc., 1940, 62, 1206; 1942, 64, 953, 2234.4 6 Ibid., 1941, 63, 2625.4 7 Ind. Eng. Chem. Anal., 1943, 15, 270.48 T. Moeller and J. G. Schnizlein, J . Physicul CoZZ. Chum., 1947, 51, 771.49 J . Amer. Chem. SOC., 1940, 62, 2444.50 2. Naturforsch., 1947, 2b, 5.b2 J . Fentress mid P. W. Selwood, J . Arne?. Chem. SOC., 1948, 70, 711.63 Nature, 1948, 101, 436.54 K. Kapitanczyk, Rocz. Chem., 1946, $30, 33.rend., 1946, 223, 1004.61 2. anorg. Chem., 1947, 254, 83, 92.56 J. Dufay, C o q t . rend., 1946, $328, 783DODD AND ROBINSON. 95in comets is more than 1%.Chemical compounds 56 in which 14C appears[produced by an (n,p) reaction from I4N], and the uses of the isotope as atracer, are ~urveyed.~7 A symposium 58 on diamond reviews crystal form,structure, and associated physical phenomena, and D. P. Mellor 59 hasdiscussed the synthesis of diamond. The action of hydrogen atoms (20%a t 0-4 mm. Hg) on soot deposits a t 45" yields 60 mainly methane with smallamounts of hydrocarbons C2-C, and no products involatile a t -100".In agreement with current ideas on combustion, J. R. Arthur 61 has foundthat when carbon is burning in air the gas within a fraction of a mm. ofthe surface contain9 0.5-2*5y0 of carbon monoxide, but away from it thecarbon monoxide content is negligible. With inhibitors present, up to 22y0of carbon monoxide was found in gas taken from about 1 mm.from thesurface, The monoxide is produced heterogeneously and oxidised homo-geneously by & chain mechanism sensitive to chlorine. W. Rudorff 62reviews work on the interesting interstitial compounds graphite oxide andgraphitic salts (nitrate, perchlorate, and, e.g,, [C24]+HF2-,2H,F2 or[C,,]+HSO,-,2H2S0,).A new carbon fluoride, (C4F),, has been described 6a and has graphitestructure with the fluorine atoms located alternately above and belowthe graphite sheets as shown (VI) with C-F distance 1.4 A. Carbon mono-/e-00-(VII.)(F atom 0 above and below the graphite sheet.)fluoride, (CF)a, has similar structure (VII) though the graphite planes areprobably puckered, and distances have been reported asc-c (interlayer) ......... .. ....C-C (ring) ..................... 1-54, 1.49 A.6 ~ 7 5 , ~ ~ 6.0 65 A.513 L. D. Norris and A. H. &ell, Bcience, 1947, 109, 265; P. E. Ymkwich, G . K.Rollefson, and T. H. Norris, J . Chem. Physics, 1946,14, 131 ; R. B. Loftfield, Nucleonics,1947, 1, 54.W. W. Miller and T. D. Price, ibid., p. 11.5* Proc. lndian Acad. Sci., 1946, A , 24, 1.69 J . Chem. Physics, 1947, 15, 525.Go G. M. Harris and A. W. Tickner, Nature, 1947, 160, 871.131 Ibid., 1946, 157, 733.G3 W. Rudorff and GT. Rudorff, Ber., 1947, 80, 417.O4 Idem, ibid., p. 413.65 D. E. Palin and K. D. Wadsworth, Nature, 1948, 162, 925.68 Ref. 5, p. 24496 INORGANIC CHEMISTRY.the second values being from a sample whose density suggests an interlayerdistance of 6.3 A.An unexpectedly large value of 231 &- 3 kcals./mole hasbeen obtained 66 for the heat of formation of CF,, and 142 f 1 is the valueobtained for COF,. A method has been described67 of preparing carbonmonoxide (designed for 13CO) by heating dry calcium carbonate and twicethe theoretical amount of zinc to 750"the product contains 99.1% ofcarbon monoxide.The properties of COSe, COTe, CO(CN),, H-COF, COClF, COBrF, COIF,COF, have been reviewed by W. Rudorff.6* Carbonyl chlorofluorideCOFCl, has been prepared 69 by shaking hydrogen fluoride and carbonylchloride in a copper bomb at 80" and 280 lb./sq. in. The product, afterseparation from carbonyl fluoride simultaneously produced, had b.p. -42",m. p. -138", mol. wt. 82-5; it is readily absorbed by sodium hydroxide,but does not react with glass. Raman spectra have shown 70 that thecompound C5C1, has a cyclic structure (hexachlorocyclopentadiene) and thatC,C160 has two isomers (VIII).The chemistries of carbon and silicon have been contrasted and com-pared.71 The thermal decomposition of di- and tri-silane has been thesubject of kinetic study72 which discredits the importance previously ascribedto silyl radicals in the decomposition, and H. J. Emelbus and A. G. Mad-dock 73 have described the preparation and properties of tetrasilane. Tworeports of interest concern the prepamtion of synthetic quartz. In thefirst, fused silica is described 74 as being mainly converted into quartzwhen heated, a t a suitable temperature, in a solution of sodium silicate.Some of the crystals were perfect though small.A natural quartz crystalshowed appreciable overgrowth in a few hours when suspended near arod of fused silica in a bath containing a " mineraliser ". In thequartz was synthesised by heating silicic acid in an autoclave with potassiumor sodium carbonate solution for three days a t 350-390'. The vapour ofcasium. fluoride proves 76 to be a mineraliser bringing about the rapid trans-formation of vitreous silica into cristobalite a t 800".66 H. von Waxtenberg, Nach. Ges. Wiss. Gottingen, 1946, 55, 57.6 7 S. Weinhouse, J . Amer. Chem. SOC., 1948, 70, 442.6 8 0. Glernser, T. Rider, V. Hiinsser, and H. Sauer, ref. 5, p. 239.69 J.H. Simons, D. F. Herman, and W. H. Pearlson, J . Amer. Chem. SOC., 1946,70 H. Gerding, H. J. Prim, and H. V. Brederode, Rec. Trav. chim., 1946,65, 168, 174.71 R. Schwarz, Chemie, 1943, 56, 258.72 K. Stokland, Tram. Paraday SOC., 1948, 44, 545.74 N. Wooster and W. A. Wooster, Nature, 1946, 157, 297.75 R. M. Barrer, ibid., p. 734; see also G. Van Praagh, Geol. Mag., 1947, 84, 98.76 R. Caillat, Ann. Chim., 1945,!20, 367.68, 1672.75 J., 1946, 1131DODD AND ROBINSON. 97Silicon tetrafluoride has been shown 76 to have no action on N,05, N204,or 99% HNO,, but to be absorbed with hydrolysis in ordinary concen-trated nitric acid and by 62.5% sulphuric acid. It is quantitatively hydro-lysed by water, SSiF, + 3H20 + 2H,SiF, + H,SiO,, the resulting solutioncontaining no free hydrogen fluoride.All three fluoroisocyanates of siliconhave been prepared; 77 the synthesis 78 and partial hydrolysis 79 of silicontetrachloride and the formation of plastic chlorides,80 e.g., Si,Cl,,, havebeen described. The latter are obtained by pyrolysis of the tetrachloridein nitrogen a t 1250" : on hydrolysis they yield Si6(OH),o0, which has beenformulated SiO(OH)*[Si(OH),],*SiO*OH. H. H. Sisler and J. C. Cory 81have obtained molecular addition compounds between diphenyl ether oranisole and chlorides of silicon, germanium, and tin: the compounds aredescribed and none was observed with carbon tetrachloride.on the chemistry of germanium given in 1944,the reaction between GeMg, and ammonium bromide has been showns3to yield three germanium hydrides, GeH,, Ge,H,, and GesH8, for whichthermal properties are given.The first, obtained in 30% yield, has m. p.-166" and b. p. -88". Dibasic monogermanic acid has been assigned 84the formula H,GeO, on the basis of a, comparison with H,C03, H,SO,, etc.Possible structures for pentagermanic acid have been considered andevidence for the equilibrium 5H4Ge0, H,Ge,O,, + 9H,O. Treat-ment of dimethylgermanium dichloride, (CH,),GeCl,, with hydrogen sulphideleads 85 to a white waxy solid, (CI<,),GeS, soluble, unlike GeS,, in acetone.Hydrolysis of the compound yields (CH,),GeO in crysta.lline, probablytetrameric, form. Atomic hydrogen reduces s6 stannous chloride to tin,stannane, and hydrogen chloride. The production of stannane is said tobe increased by the presence of methane, but in these circumstances theformation of metallic methyls must not be overlooked.H.Jeffreys 87 has considered the evidence given for the age of the earthby the relative abundance of the lead isotopes-one estimates8 of theage of terrestrial uranium is (2.9 + 0-3) x lo9 years. A n interestingaddition to our knowledge of the colouring of litharge is the observation s9that only tetragonal PbO is oxidised to read lead, Pb,04, when heated inSince the full reportG. S. Forbes and H. H. andemon, J. Amer. Chem. SOC., 1947, 69, 1241.J. J. Dodonov and M. N. Tschmmanteeva, J. Gen. Chem. Russia, 1946,16, 1949.R. Schwarz and C. Danders, Ber., 1947, 80, 444.79 W. C. Schumb and A. J. Stevens, J.Amer. Chem. SOC., 1947, 69, 726.81 H. H. Sisler and J. C. Cory, J. Amer. Chem. SOC., 1947, 69, 1515.a2 Ann. Reports, 1944, 41, 108.83 K. Clusius and G. Farber, 2. physikal. Chent., 1942, B, 51, 352.84 G. Carpeni, J. Chim. physique, 1948, 45, 128; A. Tchakirian and G. Carpeni,8 5 E. G. Rochow, J. Amer. Chem. SOC., 1948, 70, 1801.8 6 V. M. Vdovenko, J . Gen. Chem. Russia, 1945, 15, 581.Compt. rend., 1948, 226, 1094.Nature, 1948, 162, 822.I?. G. Houtermans, 2. Naturforsch., 1947, 2a, 322.A. V. Pamfllov, E. G. Ivancheva, and A. G. Ivancheve, J . Gen. Chem. Russia,1946, 16, 325.REP.-VOL. XLV. 98 INOWANIG CHEMISTRY.air, and that the rhornbic variety must fir& be converted into the tetragonalform for reaction to take pbce. As might be expected, grinding, by ds-forming the laidiice, enhances oxidkability, A reveraible reaction 90 betweenlead and sulphur dioxide probably follows the course 5Pb -+ 3S0,PbSO,,ZPbO + 2PbS.Evidence has been given 91 for the existenee of theion [Pb*OAc]+ over a wide range of concentration in aqueous solution ofl e d nitrate and ammonium acetate, and E. Grillot 92 has prepared 8omesolid acetato-lead halides. Lead penhfluoroaluminate( -21, PbAlF,, hasbeen de~cribed.~3 General surveysM have been made in the production(especially by calcium reduction 95 of the oxide), properfies, and technicaluses of zirconium and titanium. Pure ductile titanium h m been pre-pared 96 by decomposing titanium iodide vapour on a hot filament. Reduc-tions of titanium dioxide by heating with calcium, magnesium, and hydrogenyield 97 a variefy of oxides : Ti&&, TGO,, Ti,O,, TiO.With hydrogen,98Ti& is produced a t !Woo, though in the presence of calcium chloride reduc-tion commences a t 320" to yield an unidentified blue product.Zirconium hydride and metal have been obtainedg9 by reducing theoxide with 10% excess of magnesium chips a t 900" in hydrogen. Theexcess of magnesium is distilled off in the presence of hydrogen, leavingZrH,, which, heated in a vacuum, gives the metal. Neak methods 1 ofobtaining the metal from difficultly reducible oxides, such as those ofzirconium and the lanthanons, are: (i) placing the oxide on a concavetungsten disc which forms the cathode of a hydrogen are struck a t 300-400 mm.pressurep (ii) blowing the powdered oxide khrough a grapbitae tubein which a, hydrogen arc, maintained between the wall of the tube and anaxial graphite cathode, is caused to rotate by meam of an axial mgneticfield. The fractional separation of hafnium and zirconium by means oftriethyl phosphate appears, promising : the hafnium content, in weight yo,is increased from 16 to 91 in five steps, 16% of the original hafnium beingrecovered in the concentrate.completely from aluminium by a method depending upon the €act thatwithin the coacontration range 3 0 4 % HCI the solubility of AlC13,6M20decreasm greatly whereas thsh of ZrOC1, or HfOCI, inmeasm greatly with91 33. C. Purkay&ha and R. N. b-fi;fbrmp1, J . Indian Ohm. Soc., 1946,23, 31.92 Compt.r e d . , 1046,228, 151; BuU. SOC. dim., 1948,15, 284.93 T. R. Scott, J . Counc. Xci. Id. Bes. Australia, €841, 20, 114.94 W. J. Kroll and A. W. Sehl&bn, Metal Id., 1946, 69; W. H. Waggaman95 W. C. Lilliendahl and H. C . Rtmtscfir, Trans. Electrochem. Soc., 1947, 91, Pre-g6 I. E. Campbell, R. I. Jaffee, J. M. Blocker, junr., J. G d @ &nd €3. W, Gonsrer,9 7 A. Chrdtien and R. Wyss, Compt. r e d . , l947,224, i642.98 R. Wyss, Ann. Chim., 1948, 3, 215.Hafnium and zirconium may be separatedA. Chr6tisn and J. Bro@n, Corn@. rend., 1947, 225, 1315.andE. A. Gee, Chem. Eng. News, 1948,26, 377.print, p. 237.J . Electrochem. SOC., 1948, 93, 271,99 L. W. Davis, U.S.P. 2,811,524.D . L. Simonenko, Compt. rend. A d . Xei.U.B.S.S., 1946, 61, 333.H. H, Willard and K. Pxeund, Imd. €hag. Chem. Anal., 1946, IS, 195.W. Fischer and M. Zumbusch, 2. anorg. Chem., 1944, 252, 249DODD AND ROBINSON. 99rising acid concentration. If aluminium is in excess, it is precipitated bysaturation with hydrogen chloride and zirconium is recovered from thefiltrate : on the other hand, if zirconium is in excess, most of it is removedby a preliminary wystallisation from 26% HC1. Alternation of theseprocesses give a quantitative separation. After preheating to 1450-1960",96-99% pure specimens of ZrO, show rapid and large change in lengthin heating and cooling between room temperature and 1700": a mono-clinic-tetragonal transformation is the probable cause. A black, water-insoluble zirconium telluride, Zr2Te, has been described.GGroup V.-The violence of the thermal dissociation of ammoniumdichromate is reduced by the addition of 2 parts of coarsely crushedammonium sulphate ; the reaction being thus rendered a convenient methodfor the preparation of nitrogen.K. Stewart 8 has investigated the actionof active nitrogen on hydrazoio acid where the ultimate products arehydrogen, nitrogen, and, if hydrogen is present initially, ammonia. Theresults are interpreted in terms of the intermediate irnine radical, NH.Thermal, electrical, and magnetic properties and the photoconductivity loof solutions of metals in liquid ammonia have been measured, The con-siderable stability of these highly conducting inetallic-character solutionsis thought to lie in the high activation energy of the electron additionE + NH, -+ NH,- + H in liquid ammonia.The oxidation by dry airof ammonia, adsorbed on coconut charcoal, is found l1 to give hydroxyl-amine in 8 hours and ammonium nitrite in several days. Ammonium saltsin aqueous solution give l2 nitrite and nitrate ions on exposure to ultra-violet radiation. Though data on the precipitation of magnesium hydroxideby ammonia have been interpreted l3 on the basis of the equilibriaP. P. van Velden and J. A. A. Ketelaar,14 in a critical review of theoreticaland experimental work in all phases, conclude that there is no evidencefor the existence of ammonium hydroxide. The reactions between ammoniaand the oxides of nitrogen have been investigated,15 and the dissociationpressure of ammonium carbamate measured.164 R.F. Geller and P. J. Yavorsky, J . Re$. Nat. Bur. Stand., 1945, 35, 87.ti E. Montignie, Ann. Phawn. Franp., 1946, 4, 253.R. C. L. Bosworth, J . Proc, Roy. SOC. New South TVales, 1946, 79, 116.K. Stewart, Trans. Faraday SOL, 1945, 41, 663.9 A. J. Birch and D. K. C. McDonald, ibid., 1948, 44, 735.10 R. A. Ogg, junr., J . Chem. Physics, 1946, 14, 399.l1 C. Courty and L. Rougeot, Conzpt. r e d . , 1946, 2&3, 624.l2 R. Cultrero, Gazzetta, 1946, 78, 187.l3 (Mlle.) G. Gallin, Ann. Chim., 1946, 1, 277.l4 Chem. TYeekblad, 1947, 43, 401.1 5 M. Patry, R. Garlet, and S. Pupko, Compt. rend., 1947, M, 941.l6 E. P. Egan, junr., J. E. Potts, junr., and G . D. Potts, I d . E~rg. Chem., 1946,38, 454100 INORQANIC CHEMISTRY.The production of dinitrogen oxide, N,O, by thermal decomposition ofammonium nitrate has been followed l7 with 15N as a tracer, the ammoniGmcontaining 62% of 15N and the nitrate 0.38%.The expected amounts of15N20 in the product were 0.6% for random combination of all nitrogenatoms, and o.24y0 for reaction entirely between one atom from the ammoniumgroup and one from the nitrate group. The found value of 0.35% suggeststhe latter mechanism aNH4*bN02 -+ aNbNO + 2H,O with little or noaN20 or bN2O. Dinitrogen oxide has been identified l8 in the atmosphereand appears to be present to the same extent over England and America.The preparation and properties of sodium hyponitrite (Na2N20,,5H20)have been described,lg and Na, K, Ca, Ba, Sr, Cd, and Pb salts of hypo-nitric acid, H,N,O,, have been prepared; 2* the dry salts are stable in dryair and stable to carbon dioxide; the alkali-metal salts are unstable inwater and the others insoluble.The action of acids, and of heat, givenitrogen monoxide as the main product. R. A. Ogg, junr.,21 has measuredthe heat of solution of dinitrogen pentoxide in water, and from it he deducesthat in a decomposition mechanism,(1) (3) (4)(2)N205 NO, + NO, -+ NO2 + 0 2 + NO ; NO + N,O, + 3NO2,reaction (3) will be slow compared with reaction (2), and reaction (4) willbe rapid. The overall rate constant, apparently first order, will thus bea product of an equilibrium constant and a second-order rate constant.Work on peroxynitric acid has been reviewed 22-the action of hydrogenperoxide on nitryl chloride, N02C1, and on dinitrogen pentoxide yieldsHNO, in only the second case.The first leads to the formation of nitrousand hypochlorous acids, from which Bl. Schmeisser and R. Schwarz 23conclude that nitryl chloride is (IX) and not (X), and that no true chloride(IX.) NHo\O-Clof nitric acid exists. A review of nitrosyl compounds has been made,%and a tentative classification advanced based on nitrogen as an electrondonor. A new mode of formation of nitrosyl compounds has been de-scribed,25 using hydroxylamine, which appears to give the required NOgroup by a disproportionation mechanism.Nitrogen trifluoride and NHF2, but not NH,F, are among the products 261 7 J.T. Kummer, J . Amer. Chem. SOC., 1947, 69, 2559.18 J. H. Shsw, G. B. B. M. Sutherland, and T. W. Wormell, PhysicaE Rev., 1948,74, 978.T. M. 028, J . Indian Chern. SOC., 1945, 22, 225.20 K. G. Naik, C. C. Shah, and S. Z. Patel, ibid., 1946, 23, 284, 341.21 J . Chem. Physics, 1947, 15, 337.22 R. Schwarz and U. Gregor, ref. 5, p. 197.24 T. Moeller, J . Chem. Educ., 1946, 23, 542.25 W. Heiber and R. Nast, 2. Naturforsch., 1947, 2b, 321.26 W. Kwasnik, ref. 5, p. 204.*3 Ibid., p. 199DODD AND ROBINSON. 101of electrolysis of fused ammonium fluoride, the exact result dependingupon the nature of the anode material-nickel or I.G. Werk Griesheimelectrode carbon gives fluorine, Swedish graphite gives nitrogen, andAmerican graphite NH,, NHF,, and N,.The melting point of nitrogentrichloride has been measured,27 and its explosive properties investigated 28as a function of pressure. Attempts to produce nitrogen tribromide byelectric discharge in the elements were without success,29 but in the presenceof ammonia an intense red compound has been observedY30 identical withthat produced31 by the reaction between bromine cyanide and ammoniain ethyl chloride and which decomposes explosively a t -67" to nitrogen,ammonium bromide, and ammonia in molecular proportions 1 : 3 : 2. Thered compound has been assigned the formula NBr3,6NH, on the basis ofthis result, though attempts to obtain NBr, from it failed.32The conversion of colourless phosphorus into red-the term yellowpersists for the colourless variety of the element and is to be found in anotherwise excellent text issued recently-has been studied 33 between250" and 350".It is a first-order reaction, without either autocatalysis orevidence of surface reaction on the particles of the red form, and occurringrather by the coalescence of nuclei into porous aggregates. The oxidationsof red 34 and of colourless 35 phosphorus have been studied ; F. S. Dainton 36has pointed to the importance of bond energies X-X and X-0 (X = P,As, Sb) in the oxidation of those elements. Hypophosphorous acid hasbeen obtained3' in high purity by oxidising phosphine with a suspensionof iodine in water, PH, + 21, + 2H,O --+ H,PO, + 4H1, and productsof higher oxidation are not formed. A well-documented review38 of thesodium phosphates is available. Thermal analysis 39 and infra-red spectra 40of sodium phosphate melts indicate the existence of (NaPO,), and (NaP03),,and R.N. Bel141 has found all liquid phosphoric acids between H,O,P,O,and 3H,O,P,O, to be mixtures of the four species H,PO,, H4P207, H5P3010,and (HP03)6, and another, unidentified acid measured by difference. On27 M. Schmeisser, ref. 6 , p. 173.28 A. 5. Apin, J . Physical Chem. Russia, 1940, 14, 494.29 P. W. Schenk and H. Jablonowski, 2. anorg. Chem., 1940, 244, 397.90 M. Schmeisser, ibid., 1941, 246, 284.31 L. Birchenbach and M. Linhard, ibid., 1941, 247, 307.32 M. Schmeisser, ref. 5, p. 174.33 T. W. DeWitt and S. Skolnik, J . Ainer. Chem. SOC., 1946, 68, 2305; S. Skolnik,G.Tarbutton, and 1%'. E. Bergman, ibid., p. 2310.34 M. S. Silverstein, G. F. Nordblom, C. W. Dittrich, and J. J. Jakabeim, Id.Eng Chem., 1948, 40, 301.35 F. S. Dainton and J. C. Bevington, Trans. Faraday SOC., 1946, 42, 377.36 Ibid., 1947, 43, 244.3' R. Paris and P. Tardy, Compt. rend., 1946, 223, 242.38 0. T. Quinby, Chem. Reviews, 1947,40, 141.38 (Mlle.) D. Kantzer, Compt. rend., 1947, 225, 1317.40 J. Lecante, A. BoullB, and (Mme.) M. DominB-Berg&, Bull. SOC. chirn., 1948,41 Ind. Eng. Chern., 1948,40, 1464.15, 764102 INORGANIC CHEMISTRY.the other hand, in the hydration of pyrophosphoric acid V. N. Osipov42has found evidence far H,,P401,, of which magnesium and zinc salts(8 hydrogen atoms replaced) are described. Fluorophosphoric add, H,PO,F,has been prepared4, by the action of hydrogen fluoride on the pentoxideor the meta-acid at moderate temperatures.It is a, colourless oily liquid,d"' 1.82, which does not attaok glass and is a catalyst for polymerisation,oondensation, akylation, etc. Its esters are surface-active agents. (Mlle.)M, L. Delwaulle and F. Frangois44 have surnmarised the large number ofmeasurements which they have recently made of the Raman spectra ofoompounds of the type PX, and PX,(O,S) (X = halogen), prepared by themethods of H. S. Bootih and his collaborator^.^^ The compounds measuredare listed herewith :PCl, PBr, PC1,Br PClBr, PFClBrPOF, POCl, POBr, POC1,Br POClBr, POF,Cl POF,Br POPClBrPSC1, PSBr, PSC1,Br PSClBr, PSFC1, PSFBr, PSFClBr0. Schmitz-Dumont 46 has reviewed the German wotk on phosphorusnitrogen compoundsr The trimer and the tetramer of NPBr, have beenprepa~ed,~' and a number of phenyl derivatives of P4N4c14,48The density of liquid arsine has been measured 49 between -60" and30.5".Solubility studies 50 on arsenio trioxide suggcst the possibility oftwo fractions, a small one very soluble, and a bigger fraction only slightlysoluble, Preparation of metallic antimony by high-temperature electro-lysis has been described. 51 A detailed phgsicochemical investigation 52hes been made of antimonic acid, solutions of which were prepared by theaction of hydroahloric acid on pure Ag[Sb(OH),], itself obtained fromsilver nitrate and potassium antimonate. Molecular-weight determinrstionsof arylstibonic aoids show 53 that in the solid state high-molecular-weightpolymers exist but that in solution [ArSbO,H]- exists, changing to[ArSb( OH),]- in alkaline solutiofi.F. Seel's prepmation of molecularcompounds between SbC1, and various acid chlorides has been alreadyreported.54 K. A. Jensen 55 has shown that compounds of type M;[SbBr6]are intensely coloured but diamagnetic, probably owing to resonance involv-ing polybromide groupings between neighbouring [SbBr,]-- ions,The reaction 56 of bismuth tri-iodide with sodium in liquid ammonia42 J . Gen. Chem. Russia, 1942, 12, 468.4* W. h n g e and R. Livingstone, U.S.P. 2,408,784; W. Lange, U.S.P. 2,408,785.44 J. Chim. physique, 1948, 45, 50.4 7 H. Bode, 2. anorg. Chem., 1943, 252, 113.48 H.Bode and R. Thamer, BeT., 1943, 76, 121.49 P. Corriez and A. Gross, Bull. SOC. chim., 1948, 15, 203.6o H. Margulis, Compt. rend., 1947, 224, 1730.61 G. Weiss, Bull. SOC. chim., 1947, 14, 476.52 E. Buchholz and H. Viehweger, Kollaid Beih., 1940, 51, 141.68 G. 0. Dosk, J . Amer. Chem. SOC., 1946, 68, 1991.64 Ann. Reports, 1945, 42, 81.66 G. W. Watt and T. E. Moore, J. Amer. Chem. SOC., 1948, 70, 1197.See Ann. Reports, 1941, 38, 150; 1943, 40, 63. lG Ref. 5, p. 210.6 6 2. anorg. Chem., 1944, 252, 317DODD AND ROBINSON. 103solution gives black, insoluble sodium bismuthide, Na,Bi, of which thereactions have been described, Hydrolysis 57 of Bi3+ in water has beenshown by e.m.f. measurements to lead to the release of hydrogen ions andthe simultaneous formation of polynuclear ions [Bin+ 10n](n+ 3)+.These areprobably sheets, (BiO):+ in the limit, with the Bi and the 0 atoms in a squarearrangement , as in bismuth oxyhalides and oxycarbonate. A preparationof potassium and sodium bismuthates from bismuth is described.58Two vanadium arsenides have been described,59 VAs and V,As. Potentio-metric study has shown 6o that no stable vanadyl cyanides exist in acidsolution, and that addition of potassium cyanide to vanadyl salts leads toVO(OH),. The various vanadates and niobates obtained by fusion ofalkali carbonates and sulphates with vanadium and niobium pentoxide,and by evaporation of lithium metavanadate solution, have been char-acterisedYG1 as also have the vanadates obtained 62 by the action of potassiumdichromate on vanadyl sulphate.P. Souchay and S. Dubois 63 havestudied the degradation of the phospho.12-vanadate ion and deduce thatisopolyvanadates are not intermediates in the formation of heteropoly-vanadates. They have attempted a classification of complex vanadates ofdivers types. On heating niobium pentoxide in a stream of hydrogen forseveral days a t 1350-1700" a substance containing about 92% of niobiumis obtained. It had been suggested that this was Nb,O, but G. Brauer G4has now shown that it is Nb,N, presumably arising from adventitious nitrogen.It has been obtained by heating niobium powder ih nitrogen a t 1200" togive NbN and reheating this with an equivalent amount of niobium powder,whereupon Nb,N results.Attempts to produce Nb20 from NbO and Nbfailed.Group M.-An electrolytic ozoniser yielding about 12% of ozone a t12" (29% a t -13") has been described.65 M. J. S. Dewar 66 has proposeda x-complex structure for ozone, which necessitates an acute angle tri-angular configuration. A. Eucken 67 has advanced reasons for supposingthat a t 0" water contains relatively few simple molecules and consists of(H,O),, (H20) 4, and (H,O), in approximately equal amounts. Dissociationpressures measured up to the melting point of the metal and extrapolatedto the boiling point have been given G8 for oxides formed on the surface ofsixteen metals. Considerable interest continues t o be shown in hydrogenperoxide, about which there is still much to be learnt : properties of the57 F.Graner and L. G. SillBn, Nature, 1947, 160, 715.5 8 S. K. Hagen and L. Mattesen, Dansk Tidsskr. Farm., 1945, 19, 174.69 A. Morette, Bull. SOC. chim., 1942, 9, 146.6o L. Ducret, ibid., 1948, 16, 668.61 E. Carriere and H. Guiter, ibid., 1941, 8, 691, 692, 693.62 F. Rivenq, ibid., 1946, 18, 677.63 Ann, Chim., 1948, 3, 88.65 H. de Boer, Rec. Trav. chim., 1948, 6'9, 217.6 G J., 1948, 1299.67 Nach. Ges. Wiss. Gottingen, 1946, 38.68 B. Lunatman, Steel Processing, 1946, 32, 669.e4 2. Elektrochem., 1940, 46, 397104 INORGANIC CHEMISTRY.90% solution have been s~mrnarised,~~ freezing point 70 and density 7 1 ofaqueous hydrogen peroxide remeasured, and the compound H20,,2H,O,f. p. -50.5", confirmed, and a gasometric method of determination of theperoxide described which agrees well with potassium permanganate titration,optimum conditions for which are given.In the explosive combination ofhydrogen and oxygen, provided the cooling be sufficiently rapid, a condensatecontaining about 30% of hydrogen peroxide may be obtained 73 continu-ously. Hydrogen peroxide with a 15% water content can be detonated 74in steel tubes with walls 3 mni. thick, but not in thin-walled aluminiunitubes. Manganese dioxide added to 99.6% hydrogen peroxide produces anon-detonating explosive decomposition. Among the papers dealing withperoxy-salts, M. Haissinky's 75 deals with the significance of electroneg-ativities in their formation and other authors have studied peroxy-borates, -carbonates, -vanadates, -molybdates, and -tungstates. W.Kasa-totschkin 7 7 has found interatomic distances 1-35, 1-27, and 1.20 A. for[O,]--, [O,]-, and O,, which are considered to be consistent with the succes-sive rupture of two three-electron bondse e o:+o + [0-0]- -+ [O-01--.The equilibria existing between various forms of sulphur and S, havebeen calculated 78 from published thermal data. Liquid sulphur has beensupercooled v a i n bulk from 115-160" to 4 0 ' without any essential changein state, and H. Gerding has shown from Raman spectra that liquidsulphur, up to about 160", and solutions in carbon disulphide a t 18" andin naphthalene a t 110', contain principally S,, but that the liquid above160" contains some other (unknown) species in equilibrium with S,.Thelatter paper reviews Raman spectral determinations carried out in Amster-dam from 1941 to 1946 and concludes also that H,S20, is probablySO(OH),,SO, rather than SO(OH)<g>SO( OH), that S20,C1, isS02C1*O*S02C1, that SOCl, and SeOCl, arc pyramidal structures, and that69 M. E. Bretschger and E. S. Shanley, Trans. Electrochem. SOC., 1947,92, Preprint 36,7O 0. Kubaschewski and W. Weber, ref. 5, p. 158.'1 C. A. Huckaba and F. G. Keyes, J . Amer. Chem. Soc., 1948, 70, 2578.72 Idem, ibid., p. 1640.74 L. Mhdard, Compt. rend., 1946, 222, 1491.7 5 J . Chem. Physics, 1947, 15, 152.76 M. Haissinsky and M. Cottin, Compt. rend., 1947, 224, 392; K. F. Jahn, 2.Elektrochem., 1941,47,810; Chem. Zentr., 1941, I , 184; 1942,11, 511 ; M.M. Rodriguez,Anal. Pis. Quim., 1944, 40, 1270; (Mme.) M. E. Rumpf-Nordmr, Compt. rend.,1941, 212, 485.487.(Sir) A. C. Egerton and G. J. Minkoff, Nature, 1946, 157, 266.7 7 Compt. rend. Acad. Sci. U.R.S.S., 1945, 47, 193.7 8 M. Pourbaix, Bull. SOC. chim. Belg., 1945, 53, 145.7 9 R. Fsnelli, J . Amer. Chern. Soc., 1945, 67, 1832.80 J . Chim. physique, 1948, 45, 55DODI) AND ROBINSON. 105X S,C1, and S2Me, are X*S*S*X and not S*S<,. Pure sulphur is deposited 81from solutions in evacuated sealed tubes by the action of bright sunlight,the concentration of the solution having a marked effect on the time offirst appearance. The threshold concentration falls appreciably withcatalysts; thus, in carbon disulphide and 20 g./L it decreases to 1 g./l.inthe presence of rubrene (a polycyclic hydrocarbon). Other less effectivecatalysts are known.The homogeneous reaction between hydrogen and sulphur has beenshown 82 to follow the equation d[H,S]/dt = K[H,][S]*(l + [H,S][S]-l)between 350" and 550". I n the presence of a-Ag2S catalyst between 350"and 420°, rate = K'[H,][S]-l. A streaming method was used, and theresults accord well with those of E. E. Aynsley, T. G . Pearson, and P. L.Robinson,83 who found, under static conditions, a homogeneous reaction(rate = K[H,][S]$, with concentrations which made the [H2S]/[S] term inthe denominator insignificant) and a heterogeneous reaction a t the surfaceof liquid sulphur (rate = K'A[H2], where A is the area of sulphur surface).Aynsley and Robinson 84 found a further interesting heterogeneous reactionwhich takes place on a clean glass surface and continues until a unimolecularlayer of hydrogen sulphide is formed thereon.Hydrogen di- and tri-sulphides 85a mere prepared and characterised in 1923 and the penta-sulphide 85b in 1928. Hydrogen polysulphides have been further char-acterised : 8 5 ~ H,S2,H2S3 prepared by a continuous cracking process, H,S,,€I,S,, and H2S@ from sodium polysulphide solutions. Raman spectrafavour chain structures (unbranched) for these 86 and various organic deriv-a t i v e ~ . ~ ' A xylene-soluble oil, partly volatile, C,H,S,, partly non-volatileC,H,&2, and an insoluble polymer have been isolated 88 from the reactionof ethylene and molten sulphur. 33.Goehring 89 has described hydrolysisand X-ray investigations on N,S, and K,N,S,, and similar studies havebeen made of the sulphur halides and pseudolialides,g~ the lower sulphurs1 C. Dufraisse and J. Baget, Compt. rend., 1943, 217, 693 ; C. Dufraisse, C. Pinazzi,82 H. Reinhold, W. Appel, and P. Frisch, 2. physikal. Chem., 1939, A , 184,83 J., 1935, 5 8 ; R. P. Cook and P. L. Robinson, J., 1936, 454.84 J., 1935, 351.s 6 (a) J. H. Walton and L. B. Parsons, J. Amer. Chem. SOC., 1921, 43, 2539;( b ) H . Mills and P. L. Robinson, J., 1928, 2326 ; ( c ) F. Feh6r and M. Bandler, 2. EZeEtro-chem., 1941, 47, 844; 2. anorg. Chem., 1947, 253, 170; 1947, 254, 170, 289.and J. Baget, ibid., 1946, 222, 497; C. Pinazzi and J. Baget, ibid., p. 552.273.F.FehBr, Arzgew. Chem., 1947, 59, 33.J. Donohue and V. Schomaker, J . Chem. Physics, 1948, 16, 92; I. M. Dawson,8 8 H. E. Westlake, junr., M. G. Mayberry, M. H. Whitlock, J. R. West, and89 M. Goehring, Bey., 1947, 80, 110; Angew. Chem., 1944, 57, 101; ref. 5,H. Stamm and M. Goehring, Ber., 1943,76,737,1224 ; H, Bohme and E. Schneider,A. McL. Mathieson, and J. M. Robertson, J., 1948, 322.G. J. Harrad, J. Amer. Chem. Soc., 1946, 68, 748.p. 193.ibid., p. 1224; If. Goehring, ibid., p. 742106 INORGANIC CHEMISTRY.oxides 91 and acids H,SO, H,S,O,, H,SO,, H2S204, and their derivative^.^,Therein 93 is support for two derivative structures for H,SO.j, namely,H-SO*OH and S(OH),, while H2S204 appears to bc HO*S*O*O*S*OH. Thealkali salts of the latter acid may be prepared 94 by shaking the metalamalgam with pure dry sulphur dioxide a t ordinary temperatures.Thionyl fluoride (b.p. -43.7") and chlorofluoride (b. p. +12-3") and thefluoride 8OF, (a colourless offensive gas) have been prepared.95 Thepurification of crude thionyl chloride is effectedg6 by heating under refluxwith sulphur which reacts with sulphuryl chloride giving sulphur chlorideswhich are readily eliminated by fractionation. With ammonia, thionyl-imine is produced 97 as a colourless liquid monomeric above -85". At--7O", the vapour pressure is high enough for vacuum distillation, but a t---GO" a yellow solid polymer forms, as it also does on treatment of themonomer with excess ammonia. Sulphamic acid, NH,*SO,H, has beenprepared 138 from urea, sulphuric acid, and sulphur dioxide.It melts a t205", decomposes a t 209", and gives a series of metallic salts; 99 these,together with the behaviour of the acid with water and phase rule studieswith the ammonium salts, have been described. Thallium(1) and ammoniumsalts of the acid H,S05N, have been prepared2 which are isomorphouswith K2S0,N2, and X-ray diffraction shows the ion [ 80,*N<g=0]-- to have structure (XI), for which theoretical valencyexplanations are ad~anced.~ A method of freeingsulphuric acid of last traces of nitrogen is de~cribed.~Conductometric titration of solutions of sodium sulphate, chromate,molybdate, and tungstate with sodium hydroxide suggests the existenceof the ortho-acids HJO, in every case.Ortho-acids are, however, notindicated by the similar tiitration of sodium sulphite and thiosulphate.Selenium has received little attention ; hydrogen deuterium selenide,HDSe, has been prepared; 7 the photo-oxidation of hydrogen selenide hasH. Stamm and K. D. Wiebusch, Naturwiss., 1944, 32, 42; ref. 5, p. 179; P. W.Schenk, Chenz.-Ztg., 1943, 67, 251.ga (3. Rienloker and F. Gesser, ref. 5, p. 126 ; H. Stamm and M. Goehring, Angew.Chem., 1945, 68, 52; M. Goehring, Ber., 1948, 80, 219.D3 Idem, Natwwiss., 1944, 38, 42. g4 L. Rougeot, Cornpt. rend., 1946, 222, 1497.g5 J. Sol1 and W. Kwasnik, ref. 5, p. 192; I. G. Leverkmqen, Patentanmeldung,gG D. L. Cottle, J . Amer. Chem. SOC., 1946, 68, 1380.g 7 P. W. Schenk, Ber., 1942, 75, 94.J. W. Leonard, U.S.P.2,409,572; E. J. Tauch, U.S.P. 2,408,492; 2,408,823.D9 F. Oberheuser B. and H. E. Urbine C., Anales fac. JiZ. y educ., Univ. Chile,J. H. Thelin and P. A. van der Meulen, J . Arne?. Chem. SOC., 1948, 70, 1796;E. G. Cox, G. A. Jeffrey, and H. I?. Stadler, Nature, 1948, 162, 770; J. Perouze,(XI.)R. 100449.Seccihquim., 1946, 3, 109, 119; Chem. Abs., 1947, 41, 1944.S. H. Laning and P. A. van der Meulen, ibid., p. 1799.Annalen, 1835, 15, 240.a M. G. Evans and J. Gergely, Nature, 1948, 162, 770.* L. S. Olmer and F. Fouasson, Compt. refad., 1946, 222, 1398.B. V. Ramachandran, ibid., p. 450.A. Krius, 2. physikal. Chem., 1941, B, 48, 321DODD AXD ROBINBON. 107been shown 8 to require the presence of liquid water and to be autocatalysedby solid selenium; the vapour pressure of selenium dioxide has beenmeasured 9 and its chain structure confirmed (see above),80 aO*8eO*O*SeO*.E.Montignie l o has sumrnarised the chemical properties of telluribm andits compounds, especially the tel1urites.ll Conductometric titration oftelluric acid solutions with sodium hydroxide shows lZ four changes ofslope corresponding to the neutralisation of 1, 2, 4, and 6 mols. of hydroxideper mol. of TeO,. It is concluded that the acid functions as H,TeO, (cf. 8,Cr, Mo, and W above 6).A hitherto unknown stable isotope of polonium has been found l3 incertain Roumanian tellurium minerals. Previous conclusions on thereducibility of dichromium trioxide by hydrogen are not confirmed,14 andprevious observation of a greater release of water on heating in hydrogenthan in nitrogen alone is now thought to be due to the more rapid dryingof the oxide in hydrogen.In confirmation of this conclusion, no Cr or CrOhas been detected. R. Lautiit l5 has, however, obtained the Group VIAmetals and vanadium by partial reduction of the oxide with carbon monoxide,or light paraffins, a t 400-500" and then treating the product with hydrogenor ammonia a t >700°. Work on chromium(I1) iodide and hydrezinecomplexes has been reported.16 Polarographic study l7 has shown thatviolet chromium(II1) sulphate contains [Cr(H2o),l3+ while the green sulphatecontains [Cr(H20)4S04]+. Similar considerations l8 apply to hydratedchromium(II1) chloride, violet [Cr(H20),]C1, and dark green[ Cr ( H20) ,C1,]C1,2H20.Vapour-pressure measurements l9 have been made on aged chromium(II1)salt solutions and indicated equilibrium between the violet and green com-plexes.The thermal stabilities of a number of chromium(II1) complexeshave been investigated,a0 as also the suitability of various such complexesfor the electrodeposition of chromium.21W. D. Treadwell and Y. Sohaeppi 22 have proposed a constitutionalD. J. G. Ives and R. W. Pittman, J., 1948, 766.0 A. G. Amelin and M. I. Beljakov, J . Physical Chem. Russia, 1944, 18, 466.la Bull. SOC. chirn., 1948, 15, 180.l1 Ibid., 1940, 7, 651.1 2 F. Fouasson, Compt. rend., 1946, 822, 958; Ann. China., 1948, 8, 694.l3 H. Hulubei and (Mlle.) Y . Cauchois, Compt. rend., 1940, 210, 761; 1947, 224,l4 P.Pascal, Bull. SOC. chirn., 1945, 12, 627.l5 Ibid., 1940, 7, 961.l6 F. Hein and G. Bahr, 2. anorg. Chem., 1943-44, 252, 55 ; see also Ann. Reports,l7 J. B . Willis, J . Proc. Roy. SOC. New South Wales, 1946, 78, 239.l8 D. S. Datar and D. R. Kulkarni, Current Xci., 1946, 15, 251.l9 N. 0. Smith, J . Amer. Chem. SOC., 1947, 69, 91.2o T. D. O'Brien and J. C. Bailar, junr., ibid., 1945, 67, 1856.21 R. W. Parry, S. Swam, junr., and J. C . Bailar, jdnr., Trans. Electrochem. SOC.,22 Helv. Chim. Acta, 1946, 29, 771.1265.1945, 42, 75.1947, 92, Preprint 27, 311108 INORGANIC CHEMISTRY.formule for molybdenum- blue, empirically Mo601, (= Mo20,,4Mo0,),which explains the deep colour and other properties of the material. Theexistence of hexanuclear molybdenum(I1) complexes containing [M0&18]"+has been reported.23 A molybdic acid solution in the presence of alkalithiocyanates gives 24 an orange colour, soluble in isoamyl alcohol, with Fe"+or Cu++ or on addition of tin(I1) chloride.(Fe11,CuT.1)[MoV1(CNS)50]2and M O ~ ~ ~ [ M O ~ I ( C N S ) ~ O ] ~ is.indicated, the colour residing in the anion.WOF, and WF4 have been prepared : 25 the first a grey solid conipactingto shiny black flakes, as graphite, and chemically very inert, and the seconda reddish-brown hygroscopic solid, hydrolysed by hot alkalis to hydratedWO,. A considerable number of papers are available dealing with molyb-dates and heteropoly-molybdates and -tungstates, and it still appears possibleto interpret results in this very complicated field in fairly arbitrary manner.J.By6 26 concludes that dilute solutions of molybdic acid contain the singlestrong acid H2M04013 and that in more concentrated solutions H4M060,or derived ions are present. Y . Doucet and G . Carphi findY2' on re-examin-ation of results separately obtained 26 and variously interpreted, that thespecies involved approximate to the following :The formation ofMOO, concn. Species. MOO, concn. Species.0*2-0*1M. H2[ MO,6O4,] 0*0&0-002M. H2[Mo40i310.1-0.04~. H2[MO,O2j] <0*002M. H,rMoO,lSimilar conclusions emerge for tungstic acids.(Mme.) H. F r e ~ , ~ ~ investigating aqueous solutions of sodium molybdateconductimetrically, concludes that species reported to contain more thantwo molybdenums per molecule are probably mixtures of Na,MoO,,NaHMo20,, and Na2M020,. The composition of ammonium molybdatecrystallising from solution a t pH between 0.3 and 10.4 has been found3')to range between (NH4),0,10M00,,4H20 and (NH,),O,MoO,, but theseresults have not been interpreted in terms of the ionic species involved.P.Souchay 31 has described a cryoscopic method for investigating complexanions and has applied it to selenito-, sulphito-, and methylarsinato-molyb-dates among others. Salts of ethylenediamino- and py-ridino-copper, -silver,-nickel, and -mercury cations with heteropoly-tungstate and -m~lybdate,~~23 C. Brosset, Arkiv Kenai, Min. Geol., 1945, A , 20, No. 7 ; see also Ann. Reports,24 A. T. Dick and J. B. Bingley, Nature, 1946, 158, 516.26 H.F. Priest and W. C. Schumb, J . Amer. Chewa. SOC., 1948, 70, 3378.26 Ann. Chim., 1945, 20, 463.27 Compt. rend., 1947, 224, 1719; G. Carphi, Bull. SOC. chim., 1947, 14, 484, 490,28 Idem, Compt. rend., 1947, 224, 1060; Y. Doucet, ibid., p. 1361.20 Ibid., 1940, 211, 503.3O H. Guiter, Bull. SOC. chim., 1945, 12, 74.31 Ibid., 1948, 15, 143.32 M. Jean, Compt. rend., 1946, 223, 156.1946, 43, 95.492, 501DODD AND ROBINSON. 109conditions of stability 33 of phospho-3-tungstates and phospho- 1 1-tungstates,the absorption spectra 33 of tungstates, phosphates, isopolytungstates, andphosphotungstates , analytical applications 34 and other physicochemicalstudies 35 of phospho-, germano-, and silico-molybdic and -tungstic acidshave been described.Group VIL-A useful account of Moissan's life (1852-1907) and theisolation of fluorine in 1886 was given by K.R. Webb,36 and there is thereport 37 of an important symposium on fluorine chemistry held in Chicagoin 1947. This comprehensive survey deals with generation, handling, anddisposal of fluorine, the development on an industrial scale of fluorocarbonprocesses, and the chemistry of the element and its compounds. Of par-ticular interest here are a small-scale, 250-ampbre, electrolytic cell suitablefor laboratory purposes, the preparation and properties of sulphur hexa-fluoride, the vapour pressure of hydrogen fluoride solutions, the systemsBF-H,O and HF-H,SiF,-H,O, and the use of fluorine in the hydrogen-fluorine torch.Further reviews deal with the preparation, structure, andproperties of non-metal fluorides 38 and of the halogen fluorides.39 Theinter-halogen compounds CIF, ClF3 *O, 42 (= C12F6), BrF,41 and BrF, 42 arevariously studied with regard to preparation, heats of formation, and dis-sociation absorption spectra. C10,F (m. p. -115", b. p. -6") has beenprepared 43 by reaction between fluorine and chlorine dioxide diluted withnitrogen a t -50", and FClO, (" fluorine perchlorate ") was obtained 44 as ac.olourless explosive liquid (b. p. -15.9"/755 mm., f. p. -167.3") whenfluorine was passed over 72% perchloric acid in a platinum boat. Fluorin-ation of solid HIO,,BH,O, of solid potassium periodate, and of aqueousand sulphuric acid solutions of periodic acid does not, however, lead 45to the formation of fluorine periodate.Dielectric-constant measurementson hydrogen fluoride vapour indicate4, polar, and therefore more or lesslinear, polymers, in agreement with X-ray and electron-diffraction data,That the association factors indicated by dipole moment are less than thosecalculated from vapour density suggests that cyclic structures do not con-33 s. Dubois and €'. Souchay, Ann. Chim., 1948, 3, 105.34 M. Jean, ibid., p. 470.35 R. Ripan and C. Lieenu, Compt. rend., 1947,224, 196; P. Souchay and A. Tcha-36 Chem. and Id., 1946, 306.38 L. M. Dubnikov, Uspekhi Khim., 1947, 16, 189.39 H. S. Booth and J. T. Pinkston,'junr., Chem. Reviews, 1947,41, 421.40 E. Wicke, Nach. Ges. Wiss. Gottingen, 1946, 89 ; L.Domangs and J. Neudorffer,Compt. rend., 1948, 226, 920; H. Schmitz and H. J. Schumacher, 2. Naturforsch., 1947,2a, 359, 362, 363.kirian, Ann. Chim., 1946, 1, 232, 249; P. Souchay, ibid., 1945, 20, 73, 96.37 I d . Eng. Chem., 1947, 39, 236.41 P. H. Brodersen and H. J. Schumacher, ibid., p. 358.42 W. Kwamik, ref. 5, p. 168; German Patents, 5.76585, J.76482.43 H. Schmitz and H. J . Schumacher, 2. anorg. Chern., 1942, 249, 238.44 G. H. Rohrback and G. H. Cady, J . Amer. Chem. SOC., 1947, 69, 677.4 5 Idem, ibid., 1948, 70, 2603.4 6 R. A. Oriana and C. P. Smyth, ibid., p. 135; H. A. Benesi and C. P. Smyth,J . Chenz. Physics, 1947, 16, 337; see Ann. Reports, 1943, 40, 61110 ZNOBQMIU CHEMISTRY.tribute appreoiably to the dipole moment.Results thus favour successiveequilibria HF + (HF), + (HF),+I rather than the single equilibrium6HB =+ cyclic (HF),.A partial separation of 35Cl and 37Cl has been made47 by means of aClusius-Dickel separation, modified to employ two coaxial Pyrex cylinders.Sufficient chlorine containing 45% of 37Cl was obtained for the spectro-graphic determination of the nuclear spin of 37Cl. The preparation ofchlorine dioxide by electrolytic or chemical reduction of ohlorates has beenthe subject of a number of ~atents.4~ Pure chlorine passed over ferricoxide gives 49 solely ferric chloride and oxygen and the reaction is rapid at700-1000". Chlorination is accelerated by the presence of carbon. Tung-stic oxide is also attackad by chlorine a t the same temperature to giveW0,Cb.Alumina, silica, and titania, however, are not attacked even inthe presence of carbon up to 800" and a separation is thus readily obtained.The stability, hydrolysis, and polymerisation of cyanogen chloride havebeen investigated.m I?. Pierron 51 has described the preparation of solidhypochlorites by shaking solid Ca, Sr, Na, or Li hydroxides with dichlorinemonoxide in carbon tetrachloride and evaporating in a vacuum. These,and silver hypochlorites, are stable whereas sodium hypochloride is un-stable. With excess of the oxide there is a further reaction to perchlorate :M(OCl), + 6C40 --+ M(ClQ,), + 6C4.K, Clusius 52 has reported that bromine at -252" is orange and not colour-less. Procedure has been described 53 for obtaining radioactive iodine,and R.Daudel has summarised the uses to which he and his collaboratorshave put this particular tracer in work in exchange reactions, the structureof [HgI,]--, velocity coefficients of ionic dissociation, e.g., [HgI,]--Hg++ + 41-, and the origin of iodine produced in the periodate-iodidereacbion. J. Kleinberg and A. E. Davidson 55 have resently reviewed themore significant studies concerning the nature of violet and brown iodinesolutions. Molecular-weight determinations indicate that the iodine isdiatomic in all solutions, but other behaviour suggests that the brownsolutions contain free iodine in equilibrium with iodine chemically boundto the solvent. G. Kortiim and G. Friedheim 56 have concluded similarlythat the colour differences are probably due to different intermolecularforces between solute and solvent and not to differences in the degree o€dispersion of $he dissolved iodine.Evidence of absorption spectra of47 E. F. Shrader, Physical Rev., 1946, 69, 439.48 S. H. Pewon, B.P. 581,931; Swed.P. 116,363; W. S. Hutchinson, U.S.P.49 A. Chr6tien and P. GaImiche, Compt. rend., 1946, 802 ; P. Galmiche, Ann. Chim,.,60 A. B. Van Cleave and H. E, Mitton, Canadian J . Res., 1947,236, B, 4430 ; A. B. Van61 Bull. Xoc. chim., 1941, 8, 660, 664.63 0. Erbacher and M. Beck, 2. anorg. Chem., 1944, e2, 357.64 J . Chim. physique, 1944,41, 49.ti6 Chem. Reviews, 1948, 42, 601,2,409,862.1948, 3, 243.Cleave and R. L. Eager, &id., 1947, 26, F, 284.6a 2. Naturforsch., 1947, 2b, 244.2.Naturfomch., 1947, 2a, 20DODD AND ROBINSON. 111solutions in benzene, toluene , xylene, mesitylene, and methylnaphthalenefavours a donor-acceptor mechanism, and iodine in brown Bolution appearsto be sligh%ly more reactive than presumably free iodine in the viol& solu-tions. Kleinberg and Davidson have shown that Forrelabtion exibltsbetween solvent dielectric constant and mlour (solutions in ml~ants CHCI;,CH2Br*CH213r, CHCl,-CH,, and CHCKCHC1, having considerable dipole, areviolet as in non-polar CCl,) and F. Fairbrother 57 hats suggested that theeiectron-donor character of the solvent is the determining hctor. Thiswould be so if, as Fairbrother suggests, the proximity of such an ekxtrondonor to an iodine molecule stabilises one of the ionic canonicals I+I-,where I+ has an unoccupied 5p orbital, in resonance with I,, thereby destroy-ing the symmetry and altering the absorption spectrum.Parachor, rheochor, and molar refraction measurements indicate 58 thatiodic acid contains the species, (HIO,), 3 (HIO,), o.o4L”, HIO, + H+ $-IO,-.Magnetic studies 59 of periodic acid and the periodates of Na, Ag,Hg, La, Cu, Ni, Co, Y, and Ce suggest that the acid exists both in solutionand in the solid state as HIO,,BH,O and that the salts are true periodates(salts of HIO,, H,IO,, H,IO,, H,T209, H8I2OI1, and H,,I,O,, appear fromthe found compositions), none of them being complex. Manganese carbide,Mn,C, has been hydrolysed with water to yield methane, ethane, andother low alkanes; and with hydrogen chloride to givc carbon, hydrogen,and liquid hydrocarbons. The reaction between manganese dioxide andsodium oxide in fused sodium nitrite gives 61 a compound crystallising fromconcentrated aqueous sodium hydroxide as Na,Mn0,,10H20, which con-tains quinquevalent manganese with characteristic blue tint and formsmixed crystals with sodium phosphate, arsenate , and vanadate.Warminginduces disproportionation to MnO, and Mn6+ ; in concentrated alkalinesolution the equilibrium Na2MnVI1O4 + MnO, + 4NaOH + 2Na,MnV04 +2H20 obtains. The chemistry of technetium adsorbed on rhenium sulphideor copper sulphide has been described.62K. A. Jensen 63 has shown K,Re16 to be paramagnetic, in agreement withthe theory for ReIV. The reduction of ReV1’ to ReIV by chromium(I1)chloride and conditions under which ReV can be stabilised are de~cribed.~,Per-rhenates can be prepared 65 by burning rhenium to Re20,, hydrolysisto HReO,, and treating this with metal oxide or carbonate : Li, Na, K,NH,, Rb, and Cs salts are thoroughly characterised (al€ white).Group VIII.-Iron and cobalt hydrides have been preparedGg by the57 Nature, 1947, 160, 87; J., 1948, 1051.6 8 M.R. Nayar and L. N. Srivastava, Phil. Mag., 1948, 39, SOO.69 S. L. Aggarwal and S. Singh, J. I n d i a n Chem. SOC., 1945, 22, 158; R. C. Sahney,6o W. R. Myers and W. P. Fishel, J. Amer. Chem. SOC., 1945, 67, 1962.61 H. Lux, 2. Naturforsch., 1946, 1, 281.62 E. Jacobi, Helv. Chem. Acta, 1948,31, 2118.64 (Mlle.) S. Tribalat, Compt.rend., 1946, 222, ,1388.6 6 TV. T. Smith, junr., and S. H. Long, J . Amer. Chem. SOC., 1948, m, 354.6 6 R. C. Ray and R. B. N. Sahai, J. Indian Chern. Soc., 1946, 83, .61, 67.S. L. Aggarwal, and S. Singh, ibid., 1946, 23, 177; 1947, M, 193.63 2. amorg. Chem., 1944, 252, 307112 INORGANIC CHEMISTRY.reactions between phenylmagnesium bromide and the respective chloridesin ethereal solution in the presence of hydrogen. Ferrous chloride givesFeH, and ferric chloride gives FeH,, both decomposed by water and alcohol,and dissociated at about 58" into FeH, which at higher temperatures yieldsiron. Cobalt and nickel hydrides have similar properties as regards dis-sociation : XH, --+- XH -+ X. A thermomagnetic and X-ray study 67of the superficial oxidation of iron has revealed that the rate of oxidationincreases with rise in temperature, but the degree of oxidation of the productsdecreases.Hence the film formed a t 900" is almost entirely ferrous oxide.Oxidation occurs by a diffusion of iron through the oxide film to the air-film interface. A film formed at 900" and then detached from the under-lying metal becomes transformed almost completely into ferric oxide whenagain placed in air a t 900". Thin plates of iron when oxidised at 900"until no free metal remains yield films consisting of a mixture of Fe203 andFe,O,. Thermal combination 68 of iron(II1) oxide and phosphoric oxidein various ratios has yielded the phosphates Fe(PO,),, FePO,, Fe,(P,O,),,and Fe7P3OI8 as indicated by composition, X-ray, ultra-violet reflectionspectra, and magnetic susceptibility.R. S. Nyholm has prepared poly-nuclear complexes of iron(IT1) containing chlorine-bridge links and co-ordinated arsine derivatives.Potentiometric study 70 of the oxidation of nickel, cobalt, and man-ganese(I1) hydroxides shows that Ni( OH), is oxidised completely to Ni203by sodium hypochlorite, hypobromite, and peroxydisulphate, slightly onlyby sodium periodate and potassium permanganate, and incompletely toNi30, by sodium hypoiodite, ozone, and hydrogen peroxide. Cobalt(I1)hydroxide is incompletely oxidised to COO, (some CO,~,) by sodium hypo-chlorite, -bromite, or iodite,- sodium peroxydisulphate, and potassiumpermanganate; hydrogen peroxide gives a mixture of Co203 and Co30,.Manganese( 11) hydroxide is converted completely into the dioxide byall these reagents except hydrogen peroxide, which effects only partialoxidation.I n propyl alcohol and acetone solution anhydrous cobalt(I1) chloride isprobably 7 l chlorocobalt( +1) trichlorocobaltate( - l), [CoCl][CoCI,], givinglithium trichlorocobaltate( - 1) on treatment with lithium chloride.Hydr-ation then probably leads to [CoC1,],,6H20, ie., [CoC1(H20),][CoC1,(H,0)3].R. A. Robinson and J. B. Brown,', however, deduce from vapour-pressuremeasurements on cobalt(I1) chloride and nitrate, with and without addedlithium or calcium chloride, that the change in colour rose to red in thepresence of chloride is due to [Co(H,O),]++ + 2C1- ---+ [CoC&,4H20] .67 (Mme.) A.Michel, J. B. Bhard, and G. Chaudron, Bull. Soc. chim., 1944,68 P. Brasseur, ibi&., 1946, 13, 261, 436.70 J. Besson, Compt. rend., 1946, 223, 288.7l (Mlle.) Y. Wormser, Bull. Soc. chim., 1948, 15, 395.79 Trans. Roy. SOC. New Zealand, 1948, 77, 1.11, 175.J . Proc. Roy. SOC. New South Wales, 1944, 78, 229DODD AND ROBINSON. I13(undissociated) + 2H,O.complexes : [CoCl en,py]Cl,, [ Co(NH,),(NH,Me),]Cl,,IICdNH, )5NH2EfI2 (SO&, 2 73a cis- and trans-diguanidocobalt(II1) complex series,74 nitritopentammino-cobalt( +2) nitrate, [Co(NH,),(ONO)](NO,), and its isomerisation kinetics,75a series 76 of quaternary arsonium salts containing the tetrathiocyanato-cobaltate( - 2) anion, and glyoximocobalt (111) polysulphides 77 (discussedbelow with the rhodium compounds) have been severally described or dis-cussed.The co-ordination of compounds NH2f CH,],*NH, with cobalt (111)has been found 78 to occur, and the product is described where n = 3 butnot where n = 6 or 10. F. Basolo 79 has described a series of cobalt(II1)complexes with the quadridentate triethylenetetrammine. A cis-con-figuration (XII) or (XIII) is inferred from a comparison with cis-dichloro-tetrammines and cis-dichlorocthylenediammines : no trans-(XIV) seriescould be obtained.Considerable work has been done on other cobaltr w 2(XII.) (XIII.) (XIV.)An important series 8o of papers has recently appeared on syntheticchelate compounds comprising a metal (usually coba,lt), an aldehyde orketone (e.g., salicylaldehyde derivative), and an aniine ; e.g., (XV) and(XVI). These are capable of carrying oxygen as loose molecular com-pounds [(XV) carries one molecule of 0, per two Co atoms; (XVI) one73 (Mlle.) J.Brigando, Compt. rend., 1947, 225, 1319.74 P. Ray and A. N. hlajunbar, J . Indian Chem. SOC., 1946, 23, 73.7 5 B. Adell and G. Tholin, Acta Chem. Scund., 1947, 1, 624.76 F. P. Dwyer, N. A. Gibson, and R. S . Nyholm, J. Proc. Roy. SOC. New South7 7 L. Malatesta, Cfakzetta, 1942, '72, 484.7 8 J. C. Bailar and J. B. Work, J . Amer. Chem SOC., 1946, 68, 333.79 Ibid., 1948, 70, 2634.80 M. Calvin, Chem. Products, 1947, 10, 19; R I . Calvin, R. H. Bailes, W. K. Wil-rnarth, C. H. Barkelew, S. Avanoff, and E. W. Hughes, J. Amer. Chem. SOC., 1946,68, 2254, 2257, 2263, 2267, 2273; 0.L. Hark and Jf. Calvin, ibid., p. 2612; see alsoG. C. Harrison, H. Diehl, C. C. Hach, L. 111. Liggett, and R. J. Brouns, Iowa State CoZZ.J . Sci., 1947, 21, 311, 316, 326, 335.Wales, 1945, '79, 118114 INORGANIC CHEMISTRY.molecule of 0, per one Ca atom] and in this respect resemble hsmoglobin.The six papers treat : (a) general results of the investigation on oxygen-carrying chelates of this type, ( b ) rates of oxygenation, (c) oxygen produc-tion, ( d ) magnetic properties, (e) equilibria of the type, 2 uhelette (solution)+.O,(g) --+ chelate,O, (solution), and (f) similar equilibria involving type(XVI) compounds in which groups C1, F, OPh, NO,, or H occupy theposition ortho to the oxygen in the benzene nuclei. Raman specbd in-vestigation of nickel carbonyl confirms 81 a tetrahedral structure ; tetra-cyanonickelates( - 2) of beryllium, zinc, cadmium, gallium, thdliurn, andneodymium have been described.82 A number of t h i ~ l s , ~ ~ R*SH, formdiamagnetic complexes with nickel, which are probably highly polymerised,perhaps Ni(SR),-Ni(SR),*Ni(SR),.Pure platinum has been prepared 84 by converting the metal first intoK,PtCl,, then into K,Pt(NO,),, which with 20% ammonia givesPt(NH,),(NO,), : this is oxidised by chlorine to Bl~mstand’s saltwhich after recrystallisation from water is heated to give metallic platinum.Spectrally pure platinum is produced even when the original metal contains.25% of palladium.I. I. Tscherniaev 85 has described further reactions ofBlamstrand’s salts.The suggestion by A. D. Walsh has already beenreported 86 that the platinum-olefin complexes can be regarded as “ x-corn-plexes ” of the type put forward by M. J. S. D e ~ a r , ~ ’ where a dative mole-cular bond, or “ x-bond,” is formed by donation of the x electron of theolefin. Support for the suggestion is given by L. Batemans8 and byA. E. A. Werner,8s the former pointing out that the heats of formation ofsimilar complexes of CH,*CH:CH*C2H5 and of cyczohexene with aqueoussilver nitrate are approximately half those for the formation of analogousammines and that the proton affinity of ethylene (174 kcals./mole) is only10 kcals. less than that of water.It remains only to mention a few papers which add to the complexchemistry of Group VIII reported in 1946.Complex compounds of platinumwith phosphine and derivatives of phosphorous acid have been ~repared.~lThe isomerisation and dimerisation of Peyronet’s salt, Pt(NH,),Cl,, havebeen in~estigated.~, D. P. Mellor and J. B. Wi1lisg3 have contributedPtC1,(NH,),(NO,),81 B. L. Crawford and W. Horwitz, J . Chem. Physics, 1948, 16, 147.*a T. Karantassis and P. Sakellarides, Compt. rend., 1947, 224, 1640.s3 K. A. Jensen, 2. anorg. Chem., 1944, 252, 227.84 I. I. Tscherniaiev and A. M. Rubinstein, Compt. rend. Acad. Sci. U.R.S.S.,B 5 Bull. Acad. Sci. U.R.S.S., Classe Xci. Chim., 1945, 3, 203.8 6 Ann. Reports, 1946, 43, 122.87 Nature, 1945, 176, 784; J . , 1946,406, 707; Faraday SOC. Discussions, 1947,2, 50.8 8 Nature, 1947, 160, 56.91 A.A. Grenberg, S. A. Razumova, and A. D. Troitzkaja, Bull. Acad. Sci. U.R.S.S.,92 A. M. Rubinstein and L. F. Vereschtschaguine, Compt. rend. Acad. Sci. U.R.S.S.,93 J . Proc. Roy. SOC. New South Wales, 1946, 39, 141.1945, 48, 332.89 Ibid., p. 644. Q0 Ann. Reports, 1946, 43, 120.86,. Chim., 1946, 3, 253.1946, 54, 697DODD AND ROBINSON. 115further to the knowledge of the square complexes of platinum, palladium,and nickel in which steric hindrance involves considerable distortion fromthe planar structure. Dimethylglyoximorhodium polysulphides 94 have beendescribed, analogous to the cobalt compounds mentioned above." Bothare formed by the treatment of the metal chloride and dimethylglyoximein aqueous alcohol with ammonium or sodium polysulphide. If sodiumpolysulphide is used for the cobalt compound some amine or ammoniamust be present otherwise cobalt aulphide is quantitatively precipitated.The compounds are probably polymeric containing [MIIIR2]+ units joinedtogether by S,, S4, or S, chains in the caBe of the cobalt, and S, chains inthe case of the rhOdium compound (R represents OH*N:CMe*CMe:NQ*).Finally, F.P. J. Dwyer and R. S. Nyholm 95 have prepared and isolated acomplex of qua+vabnt rhodium in the green insoluble Cs,RhI"Cl, formedby oxida6ion of a fine pink suspension of CS,R~~~~CI, by a solution of caesiumnitrate in dilute nitric acid. The face-centred cubic structure of Cs2RhCl,is isomorphous with (NHp),PtCl,.Lmthanons and Actinons.*-A greatly simplified treatment of monazitehas been described by F.R. Hartley and A. W. W ~ l i e . ~ , The direct chlorin-ation at 700-750" of monazite, briquetted with wood charcoal, has theadvantages that phosphorus is directly volatilised a6 POCI,, which can becondensed to serve as a reaction indicator, t h a t other impurities are largelyeliminated as volatile chlorides, and that anhydrous lanthanon chlorides aredirectly obtained. Approximately the reaction is : MPO, + 3C + 3c1, -+MCl, + POCl, + SCO.S. Takvorian 97 has further considered the separation of ceric lanthanons,complex compounds of lanthanons with antipyrine and pyramidon havebeen described,gs and a, dilatometric investigation 99 of cerium oxides sug-gests that the blue oxide Ce,O, is a salt-like oxide and not a mixed oxide,2CeO,,Ce,O,.D. C. Hess has investigated isotopic abundances in Eu,Gd, and Tb and calculated atomic weights therefrom :Internationalvalue. Isotopes ( > 0.02%).Eu ........................... 151.97 152-0 151 and 153Gd ........................... 157.26 156.9 152, 154, 155, 156, 157, 158, 160Tb ............................... 158.94 159.2 15994 L. Malatesta and F. Turner, Gaxxetta, 1942, 72, 489.95 Nature, 1947, 160, 502.96 Jbid., 1948, 161, 241.9 7 Cornpt. rend., 1947, 224, 124.9 8 D. I. Riabtschikov and E. A. Terentieva, Compt. rend. Acad. Xci. U.R.S.S.,99 M. Foijx, Gompt. rend., 1946, 222, 660.* The term actinon seems preferable t o actinide.1946, 51, 291.1 Physical Rev., 1948, 74, 773.The justification for either lies inthe elements 93-96 having the correct number of 5f-electrons for a series with itsorigin in actinium. The term does not presume the existence (as yet uncertain) off-electrons in Th, Pa, or U, nor does it imply that those elements do not also show thevalencies and properties of sub-groups IVA, VA, and VIA, respectively116 INORGANIC CHEMISTRY.An article by A. G. Maddock,, with comprehensive bibliography, furtherreviews the chemistry of the actinons in the four radioactive series 472,4n + 1,3 4n + 2,4 4n + 3, and the growing evidence for regarding theactinons as a second series of f-shell elements.W. H. Zachariasen 7 has investigated the various two-component systemsbetween sodium or potassium fluoride and UF,, ThF,, or LaF, and hastabulated lattice dimensions for KNb2F9, KPu,FS, NaPuF,, KPuF,, RbPuEj,and p,-NaPuF,. The analytical chemistry of thorium has been reviewed,sas has the occurrence of uranium in minerals and its bearing on paragenesis,genetic history, and the geochemical cycle. Uranium oxides,lO~ l1 UO, UO,,u02.34, U30,, and UO,, have been prepared and examined by X-rays, ashave the carbides,ll> l2 UC, U2C3, and UC,, and nitrides,ll UN, U,N3, andUN,. The oxide UO (only known from X-ray data), UC (qction of methaneon uranium above 625"), and UN have sodium chloride structures. U2C3exists only a t high temperatures (>2000"); U2N3 is isomorphous withMn203 and disproportionates with increased pressure to UN and UN,.UC, (U308 + 14C or U + 2C a t 2400") and UN, (stable only a t high pres-sure) have CaC, structures. Preparation of uranium fluorides, UF, l 3 andU2F9,l4 has been described. The latter is a black compound changing togreen UF, on exposure to air and has a cubic structure where all the uraniumatoms are equivalent. This indicates either that U(IV), U(V), and U(V1)replace each other isomorphously or that each uranium atom resonatesbetween valency states of four and higher. A method of purification ofUF, is described l5 which enables it to be kept for long periods in previouslywell baked out vessels : vapour pressure, dielectric constant, and ultra-violet absorption have been measured. Uranium(1V) sulphate has beenshown l6 to be quantitatively coprecipitated with lanthanon sulphatesResearch, 1948, 1, 690.F. Hagemann, L. T. Katzin, M. H. Studier, A. Ghiorso, and G . T. Seaborg,PIzysical Rev., 1947, 72, 252; A. C. English, T. E. Cranshaw, P. Demers, J. A. Harvey,E. P. Hincks, J. W. Jelley, and A. N. May, ibicE., p. 253.M. H. Studier and E. K. Hyde, PhysicaE Rev., 1948, 74, 591.C. A. Hutchinson and N. Elliott, J . Chem. Physics, 1948, 16, 920.J . Amer. Chem. SOC., 1948, 70, 2147.S. I. Tomkieff, Sci. Progress, 1946, 34, 696.* T. Moeller, G. K. Schweitzer, and D. D. Starr, Chem. Reviews, 1948, 42, 63.lo F. Grenvold and H. Haroldson, Nature, 1948, 161, 69; F. Grenvold, ibid:, 1947,l1 R. E. Rundle, N. C. Bamziger, A. S. Wilson, and R. A. McDonald, J . Amer.l2 L. M. Litz, A. B. Garrett, and F. C. Croxton, ibid., p. 1718.l3 H. S. Booth, W. Krasny-Ergen, and R. E,Heath, ibid., 1946, 68, 1969.l4 R. Livingston and W. Burns, Manhattan Project Report, CN 982, October, 1943 ;S. Weller, A. Grenall, and R. Kunin, Report A3326, March, 1945; W. H. Zachariasen,J . Chern. Physics, 1948, 16, 425.l5 C. B. Amphlett, L. W. Mullinger, and L. F. Thomas, Tram. Paraday SOC., 1948,44, 927.l6 A. W. Wylie, Nature, 1947, 160, 830.161, 70; P. Jolibois, Compt. rend., 1947, 224, 1395.Chem. SOC., 1948, 70, 99DODD AND ROBINSON. 117(under certain conditions), and hydrolysis of uranyl nitrate, both on dilutionand with sodium hydroxide, has been followed l7 potentiometrically.G. T. Seaborg and A. C. Wahl l8 have given fixrt'her chemical properties ofneptunium and plutonium.R. E. DODD.P. L. ROBINSON.1' H. Guiter, Bull. SOC. ckim., 1947, 14, 64; 1946, 13, 403.J . Arnsr. Ghern. Soc., 1918, 70, 1128

ISSN:0365-6217    

DOI:10.1039/AR9484500082

出版商:RSC    

年代:1948

数据来源: RSC

摘要:

ORGANIC CHEMISTRY,1. INTRODUCTION.THE subjects selected for inclusion in this Report deal with some recentlyintroduced general methods, developments in the reactions of fiee radicalsand atoms, mono- and di-terpenes, colchicine and related compounds, somereactions of organic sulphur compounds, and certain groups of heterocycliccompounds.I n a survey of new general methods reference is made to the introductionof lithium aluminium hydride, which has proved to be a most useful reagentfor effecting a wide variety of reductions, and in particular the ready con-version of -CO,H into -CH,*OH. The process of cyanoethylation is findingnumerous applications in synthetic organic chemistry, and a considerablevolume of new work has centred around the preparation and properties ofcyanides.Particular refhence should be made to the conversion of cyanidesinto amidines by a number of new reactions. The introduction of the-CH,=CO,H group directly into an aromatic nucleus has been effected bya dehydrogenating condensation with acetic anhydride and potassiumpermanganate. A general method for preparing amides has been reportedwhich consists of heating the acid with urea. Several new general methodsfor the preparation of certain amino-acids have been published, and mentionis made of the formation of a p-lactam from diazomethane and an isocyanate.Great advances have been made in the utilisation of simple compoundssuch as acetylene, ethylene, and carbon monoxide, and the processes ofhydroxylation, chloromethylation, aminomethylation, sulphomethylation,nitrosation, oxynitration, and nitration (with sulphuric acid) have receivedconsiderable attention.Certain general reactions among organic com-pounds of phosphorus have now become h l y established. Dibenzylchlorophosphonate has been employed in the synthesis of complex sub-stances such as adenosine triphosphate, and esters of fluorophosphoric acid(having powerful anti-cholinesterase activity) are readily prepared by simplemethods.A survey of developments in the reactions of free radicals and atomsduring the past four years shows that reactions of this type are more wide-spread than seemed likely a comparatively short time ago. Many newexamples have been brought to light, and the added knowledge thus gainedconfirms and extends the main theoretical views which had already beendeveloped. There is now clear evidence of a duality of function in manycompounds which, under appropriate experimental conditions, can takepart in either a homolytic or a heterolytic process.M. S. Kharasch andhis collaborators have made an extensive study of the uses of acetyl per-oxide, which acts as a convenient source of methyl radicals, and theseinvestigations have led to the development of many novel synthetic methodsHEY AND JONES : INTRODUCTION. 119The use of acyl peroxides for the alkylation of quinones has also been furtherextended. Considerable attention has been devoted to the kinetics of thedecomposition of benzoyl peroxide in solvents; this is now considered toinvolve a secondary chain reaction in addition to the true unimolecularprocess.The remarkable properties of tert.-butyl peroxide have attractedwide interest ; its reactions have been studied both in the vapour phase andin a variety of solvents, and a simple rate-determining dissociation process,involving the scission of the 0-0 bond, is common to both types of reaction.New contributions have been made to the theory of free-radical additionreactions, and a considerable extension of our knowledge of these reactionshas resulted from further work on the addition to olefins under peroxidicconditions of various halogen derivatives of methane, derivatives of halo-genated acids, phosphorus trichloride, trichlorosilane, and various sulphurcompounds.Me* + XY -+ MeX + Y*These reactions can be represented by the general scheme :R*CH:CH, + Ye + R*(?H*CH,YR*kH*CH,Y + XY + R*CHX*CH,Y + Y*The substitution reactions of atomic halogens have also been furtherexplored.For bromination great use has been made of N-bromosuccin-imide, and for chlorination further reactions have been described withsulphuryl chloride in the presence of a peroxide. New reactions whichreveal a free-radical mechanism include those of diphenyliodonium hydroxideand phenyl iodosoacetate, and oxidation processes using selenium dioxideand chromic anhydride have also shown free-radical characteristics. Theuse of cobaltous chloride to induce free-radical reactions with Grignardreagents has been further extended.The review of recent advances in the terpenes is limited to some aspectsof the chemistry of the mono- and di-terpenes. The monoterpene sectionis devoted to the important series of esters derived from the chrysanthemummono- and di-carboxylic acids (I ; R = Me, and I ; R = C02Me, respectively),monoterpenic acids containing the unusual feature of an unfused cycEo-propane ring, and cyclic keto-alcohols of the type (11; R = alkyl oralkenyl).The esters derived from (I1 ; R = CH,*CH:CHMe orCH,*CH:CH*CH:CH,) are the constituents of pyrethrum flowers (Chrys-anthemum cinerariifolium) responsible for their remarkable insecticidalproperties. As these substances have not been reported on before, a briefsurvey has been made of the development of our knowledge of their struc-tures from the time of their discovery by H.Staudinger and L. Ruzickamore than twenty-five years ago. Although their total synthesis has notyet been accomplished, the remaining difficulties should not prove insuramouhtable. By the study of synthetic analogues much light is bein120 ORGANIC CHEMISTRY.thrown on the relationship of toxicity to structure. The section on thediterpenes is devoted to the resin acids containing the hydrophenanthreneskeleton. Although the structure of abietic acid was settled by 1941, thestructures of sapietic, pimaric, and other resin acids have remainedin doubt until recently-. Conspicuous advances have been made in theisolation of primary resin acids, which have disclosed that abietic, di-hydroabietic, and dehydroabietic acids, formerly regarded as artefacts,do in fact occur as such in pine oleoresin.The structure of pimaric acidhas finally been settled as one containing a gem.-vinylmethyl group at C,in preference to a structure with an angular vinyl group at C14. Workon agathic acid (a dicyclic diterpene) and on podocarpic acid, which is nota terpene although containing the hydrophenanthrene skeleton, is described,since this has an important bearing on the elucidation of the stereochemistryof the resin acids. The configurations of C,, C,,, and CI2 have now beenelucidated with reasonable certainty by a study of their interrelationships,by degradation to a common tricarboxylic acid in which ring A remainsintact, and by a study of lactone formation in the dihydro-resin acids.The application of a theoretical analysis of the dissociation constants ofthe tricarboxylic acid to this configurational problem together with thesuggestion that lactone formation is preceded by structural rearrangement(the angular methyl group migrating from C,, to CIS) constitutes a usefuadditional approach to these problems.The concept of cydoheptatrienolone (tropolone) as a new type of reson-ating aromatic system has proved extremely useful for interpreting thestructures of a numbe’r of natural products.These are shown to range incomplexity from the relatively simple mould-product stipitatic acid and agroup of products isolated from the heartwoods of red cedar, throughpurpurogallin and its analogues which are now regarded as benztropolonederivatives, to the tricyclic system of the acetylated alkaloidal amine,colchicine.I n these compounds, generally, ethylenic and carbonyl func-tions are revealed by the results of hydrogenation but are masked towardsthe usual reagents and become incorporated in a carboxylated benzenoidring through rearrangement in strongly alkaline media ; there is supple-mentary evidence for the tropolone structure in: most of them, and it nowrewins for the rational synthesis of a typical tropolone to set the seal onthe degradative and interpretative work. The present state of the structuralchemistry of colchicine is reviewed. Recent work indicates that the com-pound mag contain a second 7-membered ring in addition to the tropolonesystem.After the tropolone ring has been converted into a benzenoidform, further degradation yields products which are identified as dibenz-cycloheptatrienes. Attention is thereby directed to the synthesis andtransformations of compounds of this type.I n recent years, interest in the chemistry of organic sulphur compoundshas been stimulated by the discovery of several physiologically activenatural products containing sulphur-for example, aneurin, biotin, andpenicillin. A t the same time, an appreciation of the use of organic sulphuHEY AND JONES : INTRODUCTION. 121compounds, which are often more reactive than their oxygen analogues, hasled to new synthetic methods and improvements on previously known ones.In 1939 the remarkable discovery was made that sulphur can be removedfrom, or replaced by, hydrogen in many different ty-pes of inorganic andorganic substance by means of Raney nickel.This reaction has alreadyfound numerous applications in synthetic work, and has been particularlyuseful for the elucidation of the structure of organic sulphur compounds :thus it was of great importance in connection with biotin and penicillin.Raney-nickel hydrogenolysis does not cause racemisation of opticallyactive molecules ; for example, natural( -)rnethionine yields L( +)-%-amino-butyric acid, thereby confirming that the former has the same absoluteconfiguration as the other natural (L) a-amino-acids. Similarly, the stereo-chemistry of penicillin and of the natural and synthetic stereoisomers ofbiotin has been studied.The ease of cyclisation of many thioacylamido-compounds has led to new methods for the synthesis of derivatives ofglyoxaline, oxazole, and thiazole. The required intermediates can some-times be made by the action of phosphorus pentasulphide on the corre-sponding amides, but this reaction is not always satisfactory. A muchbetter method is the direct thioacylation of amines by means of dithio-acids, their salts or esters, or by thion-esters. The Willgerodt and Kindlerreactions have been studied extensively in the last few years and so modifiedthat excellent yields of substituted phenylacetic acids are now obtainable.The preparation of aromatic aldehydes by the McFadyen-Stevens and theWuyts reaction, the use of thiourea for the synthesis of pyrimidines andpurines, of 5-methylthiouronium salts for guanidines and rhodanine, andof 2-thiothiazoline for a-amino-acids have also been outlined.In the heterocyclic series the chemistry of aziridines, P-biotin, and thepterins is reviewed.Under the first heading attention is directed to themore recent interest shown, since 1941, in the preparation and propertiesof ethyleneimines. Under the second heading recent syntheses of three ofthe stereoisomeric racemates of the biotin structure including the hithertounknown ( f )-epibiotin are outlined. By chemical control of configurationsthe methods make feasible the preparation of all four racemates from asingle intermediate, and the need to separate mixtures of racemates isthereby obviated.Finally, a review is included of the advances made inthe field of pterin chemistry since the previous Report of two years ago,New syntheses of vitamin B, and pteroic acid are reported together withexperiments concerning the degradation and synthesis of the fermentationL. casei factor and a new pterin growth-factor, rhizopterin. Attention isdirected to investigations on the reduction of some pteridines, includingvitamin B,, the synthesis of compounds antagonistic to vitamin Bc, andpreparations of numerous simpler pteridines. Experiments on the utilis-ation of sugars, and recent views concerning the authenticity of preparationsof hgdroxy- or halogeno-methylpteridines, are ttlso reported.13. H. H.B. J122 ORGANIC CHEMISTRY.8. (3ENERAL mTHODS.Reduction.-Since the last Report on General Methods,l outstandingadvances have centred round the use of lithium aluminiiiin hydride, LiAIH,.Th4 organic chemist has always been handicapped by the lack of a suitablegeneral method for converting the -CO,H group into -CH,*OH.This newreagent now promises to give the answer to this age-long problem, and tobe of considerable general use in effecting a wide variety of reductions.Lithium aluminium hydride was discovered in 1947 by A. E. Finholt,A. C . Bond, and H. I. Schlesinger who treated finely divided lithiumhydride with an ethereal solution of aluminium chloride. Lithium aluminiumhydride was thus obtained as an ether-soluble solid according to theequation :4LiH + AICl, --+ LiAlH, + 3LiC1.Larger quantities of aluminium chloride gave aluminium hydride :3LiAlH, + AlC1, -+ 4A1H3 + 3LiC1.By the use of lithium aluminium hydride, new methods, simpler than thosealready available, were a t once developed €or the preparation of hydridessuch as silane and stannane and of their alkylated derivatives. (Thehitherto unknown hydridcs of zinc and beryllium have also been prepare’d.) :LiAIH, + SiCl, -+ LiCl + AlC1, + SiH,LiAlH, + 2Me,SnCl, --+ LiCl + AlCl, + ZMe2SnH,LiAlH, + ZnMea -+ LiAIMe,H, + ZnH,These reactions usually proceed smoothly at room temperature, and givehigh yields of pure products. The authors point out that in certain reduc-tions of this type lithium hydride and aluminium hydride can be used inplace of lithium aluminium hydride. With lithium hydride, however, thereacticns are slower and the yields poorer.R.F. Nystrom and W. G. Brown3 used lithium aluminium hydride forrcducing aldehydes, ketones, esters, and acid chlorides to the correspondingalcohols. The reaction proceeds in ether, at room temperature, and yieldsare of the order 70-98%. Points in favour of this reagent are : (a) nospecial apparatus is required, ( b ) it is claimed to be indefinitely stable atroom temperature. The most notable advance, however, by these authors,concerns the smooth reduction of carboxylic acids to the correspondingprimary alcohol by lithium aluminium hydride. An ethereal solution ofthe acid is added dropwise to an ethereal solution of the reagent at such arate as to maintain a gentle reflux.After 15 minutes, the cooled productis diluted with water and treated with 10% sulphuric acid (or loo/, sodiumhydroxide solution), leaving the alcohol in the ethereal layer. Free hydroxyland amino-groups do not interfere. The double bond in cinnamic acid,but not those in sorbic or furoic acid, is simultaneously hydrogenated.1 R. A. Baxter and F. S. Spring, Ann. Reports, 1945,42, 96.* J . Amer. Chem. SOC., 1947, 69, 1199.208 ORGANIC CHEMISTRY.Dithio-acids are unstable and decompose on keeping. Dithioformic 58 anddithiophenylacetic 69 acids are best stored as the stable potassium salts.Dithio-esters are stable, and the methyl estcrs of dithiophenylacetic 68, 7Oand dithio-n-hexoic 7 l acids have been used for thioacylation.Dithio-benzoic acid is less reactive than the aliphatic dithio-acids and does notR*CS,Me + NH,*CHR’*CO,H .“.‘k“‘t R*CS*NH*CHR’*C02Hreact with glycine or leucine even on warming.7, Amino-acids can, how-ever, be thiobenzoylated by means of carboxymethyl dithi~benzoate.?~Ph*CS,*CH,*CO,H + NH,*CHR*C02H ,-f%+ Ph*CS*NH*CHR*CO,HUnfortunately aliphatic dithio-acids (except dithioformic 74 and dithio-phenylacetic 75) cannot be obtained in good yield. However, aliphatic 69and aromatic 677 76 thion-esters (R*CS*OR’) can be used in place of dithio-esters, and they are easily prepared by the action of hydrogen sulphide oniminoethers.7’ Thiobenzoyl chloride 78 (Ph-CSCI), prepared by the actionof oxalyl chloride or thionyl chloride on dithiobenzoic acid, is reported toreact vigorously with aniline to give thi~benzanilide,~~ but does not reactin the expected way with amino-a~ids.~~ Attempts to prepare thiophenyl-acetyl chloride (Ph*CH,*CSCI) were unsuccessful ; oxalyl chloride andpotassium dithiophenylacetate yielded 4 : 5-diketo-2-benzylidene- 1 : 3-di-thiolan (XXXIV) .Attempts to prepare the potentially-useful thiophenyl-Ph*CH:C<S,CO S-YO Ph*CH,*wN-N>C*CH,PhN=N(XXXIV.) (XXXV.)acetyl azide (Ph*CH,*CS*N,) were also unsuccessful, since the dithio-aciddid not react with sodium azide, while methyl dithiophenylacetate andhydrazine gave 3 : 6-dibenzyl-1 : 2 : 4 : 5-tetrazine (XXXV) and otherproducts instead of the desired hydrazide.80 Thiobenzhydrazide has been69 W.Baker and J. F. W. McOmie, unpublished results; J. F. W. McOmie, D.Phil.Thesis, Oxford, 1946.70 A. R. Todd and A. Topham, CPS 93; J. Wardleworth, A. R. Todd, P. Sykes,5. Baddiley, and H. T. Openshaw, CPS 351; R. Bentley, J. R. Catch, A. H. Cook,(Sir) I. M. Heilbron, and G. Shaw, CPS 267, 328; E. P. Abraham, W. Baker, E. Chain,and (Sir) R. Robinson, CPS 342; Lilly Research Laboratories, CPS 286, 364; W. E.Bachmann, CPS 335, 358 ; Squibb Institute for Medical Research, CPS 452.71 A. H. Cook, J. A. Elvidge, and (Sir) I. M. Heilbron, CPS 273.72 Squibb Institute for Medical Research, CPS 278.73 B. Holmberg, “ The Svedberg Memorial Volume,” p. 299, Stockholm, 1944;74 T. G. Levi, Cazzetta, 1924, 54, 395.7 5 J. Houben, Ber., 1906, 39, 3227.78 (a) E.P. Abraham, E. Chain, W. Baker, and (Sir) R. Robinson, B.P. 588,101,1947; (b) A. A. Goldberg and W. Kelly, J., 1948, 1919.7 7 Y. Sakurada, Mem. Coll. Sci. Kyoto, 1926, 9, 237.78 H. Staudinger and J. Siegwart, Helv. Chim. Acta, 1920, 3, 824.7s Squibb Institute for Medical Research, CPS 301.B0 A. H. Cook, J. A, Elvidge, and (Sir) I. M. Heilbron, CPS 328.Arkic Kemi Min. Cr’eol., 1944, 17 A, 1 ; D. F. Elliot, Nature, 1948, 162, 658MCOMIE : ORGANIC SULPHUR COMPOUNDS. 209prepared by B. Holmberg,73 but its reaction with nitrous acid has not beentried.218 ORGANIC OHEMISTRY.presence of water,16 aluminiun chloride,17 or aqueous mineral acid,ls butnone of the methods is suitable for preparing the anhydrous diamines.L. B. Clapp finds that the reaction proceeds well under anhydrous con-ditions at 100” with ammonium chloride as catalyst.In this manner2-ethylethyleneimine with liquid ammonia (40-fold excess) gives 1 : 2-butylenediamine, in 55 yo yield, and very little polymer, while with variousalkyl- and cycloalkyl-amines (in %fold excess) 2-amino-l-alkylamino-n-butanes (R = Et, R’ = H) are formed. 2-Amino-l-alkylaminoisobutanes(R = R’ = Me) arise from 2 : 2-dimethylethyleneimine :RR’C-CH, I I RR’C-CH, RtiR’tjNgNH, NR”R”’\ / - NHRing opening therefore occurs preferentially at the primary carbon. How-ever, in the case of reactions with aniline appreciable amounts (9--22%)of the alternative ring-scission products are also formed.Only a few examples of the above type of reaction (substituted-aziridinering-scission) have previously been recorded.Catalytic hydrogena’tion 2oand reaction with hydrogen bromide21 proceed with ring opening a t theprimary carbon, whereas hydrolysis lo occurs with scission at the tertiarycarbon rather than at the primary (or secondary,13 see above) :RR’$F--CH,*NH,OHRR‘C--CH,\ /NH % RR’$F--CH,X(X = H or Br)NH2When a mixture of ethyleneimine and acetic acid a t -78” warms toroom temperature 2-acetoxyethylammonium acetate (V) is formed,22 whichHOAc VHz>NH ---+ AcO*[CH2],*NH,,HOAc (V.)CH2l6 U.S.P. 2,318,729.l7 A. L. Coleman and J. E. Callen, J . Amer. Chem. Soc., 1946, 68, 2006.l8 G. I. Braz amd V. A. Skorodumov, Compt. rend. Acad. Sci. U.R.S.S., 1947, 55,l9 J . Arner.Chem. SOC., 1948, ‘SO, 184.2o J. V. Karabinos and K. T. Serijan, ibid., 1945, 67, 1856; K. N. Campbell, A. H.Sommers, and B. K. Campbell, ibid., 1946, 68, 140.21 S. Gabriel and H. Ohle, Ber., 1917, 50, 804.22 G. D. Jones, J. Zomlefer, and K. Hawkins, J . Org. Chem., 1944, 9, 500.315ELVIDGE : HETEROCYCLIC COMPOUNDS. 219on heating in an open vessel cf- 23 loses acetic acid and water and cyclises to2-methyl-A2-oxazoline (VI) ; in a closed system re-arrangement to 2-acet-amido ethanol (VII) occurs.An example of possible further applications of ethyleneimines in syntheticwork is the preparation by H. Gilman et aZ.24 of ethyleneiminyl-lithium(VIII) which was employed for the synthesis of a quinoline derivative (IX)as follows :(VIII.)A new class of aziridine derivatives has been discovered by N.H. Crom-well and his co-workers 25 who observed that interaction of phenyl a-bromo-styryl ketone (X) and phenyl 1 : 2-dibromo-2-phenylethyl ketone (XI)with benzylamine and cyclohexylamine afforded colourless products. Fromultra-violet absorption data 26 and chemical evidence these products wereconcluded27 to be ethyleneimine ketones and not compounds of the typePh*CO-CH:CPh*NHR as had earlier been suggested : 28, cf*Ph-CH:CBr COPh* Ph*CH-CH-COPhNR(X.) 1\ /Ph*[CHBr],*COPh(XI-)Ph*vH--vH*COPh Ph*vH*CHCl*COPhPh*CH,-NH,+ SO,- R*NH,HCl(XIV.) (XIII. )Treatment 25 of the products (XII) with hydrogen chloride resulted in theuptake of two molecules of the acid and formation of chloro-amine salts23 H.Wenker, J. Arner. Chem. SOC., 1935, 57, 1079.24 H. Gilman, N. N. Crounse, S. P. Mwsie, junr., R. A. Benkeser, and S. M. Spatz,25 N. H. Cromwell, R. D. Babson, and C. E. Harris, ibid., 1943, 65, 312.26 N. H. Cromwell and R. S. Johnson, ibid., p. 316.2' N. H. Cromwell and J. A. Caughlan, ibid., 1945, 67, 2235.2 8 S. Ruhemann and E. R. Watson, J., 1904, 1181.29 J. Agar, A. Hickey, and P. G. Sherry, Proc. Roy. I&h Acad., 1943, 49, B, 109.ibid., 1945, 67, 2106220 ORGANIC CHEMISTRY.(XIII). In dry ether, the hydrochloride of (XII; R = CH,Ph) could alsobe obtained. With sulphuric acid, (XII; R = CH,Ph) yielded a high-melting, sparingly soluble substance which, in view of its ready recon-version into (XII; R = CH2Ph) by treatment with alkali, was formulatedas the internal salt (XIV).Methylamine was also found 27 to condense with (XI) to form an imine(XII; R = Me), the aziridine structure of which was well substantiated byits reaction with hydrogen chloride to yield (XV), ring opening havingoccurred in opposite sense to that previously observed :Additional evidence in support of the aziridine structures of theseimino-ketones has recently been obtained.30 Thus the products (XVI ;R = Ph, R‘ = p-Me*C,H,) and (XVI; R = p-Me*C,H,, R’ = Ph), derivedfrom benzylamine and the appropriate ap-dibromo-ketones in ethanol at>40”, were found to react merely as normal ketones with Grignard reagents,affording the corresponding carbinols :(XVI.)Possible open-chain structures are consequently ruled out, and incidentallythe behaviour indicates that the ethyleneimine ring is stabilised by theintroduction of an alkyl substituent in the l-position.p-Biotin.Stereochemicd Studies.-In the previous Report on biotin 31 evidenceconcerning the configurations of the four racemates of (XVII), ( A)-,(&)-epi-, (f)-epiaZlo-, and ( f)-allo-biotin, was reviewed.This evidencesuggested that the configurations about the C3-C4 linkage were trans in( f)-allo- and (&)-epiaZZobiotin, whereas in (&)-biotinthe C,-C, configuration was cis. More recently cothese conclusions have been rigidly verified by NH NHB. R. Baker and his associates. These workers have 1-1 ;CH,14.co2H elaborated methods of obtaining singly any of the\5/2 four racemates of (XVII), starting from only one1 (xvll.) intermediate (XXI; R = [CH,],*CO,H) : by chemicalcontrol of isomers the need to effect separations by fractional crystallisationwas obviated.Besides providing new syntheses of (&)-biotin and (&)-/ \so N. H. Cromwell, J . Amer. Chem. S O ~ . , 1947, 69, 258.31 Ann. Reports, 1946, 43, 239ELVIDOE : HETEROCYCLIC COMPOUNDS. 221epiaZZobiotin the procedures have enabled the hitherto unknown ( &)-epibiotinto be obtained. Though perfectly feasible, the synthesis of (&)-aZZobiotinfrom (XXI; R = [CH,],*CO,H) was not attempted. The work may con-veniently be considered under two headings : ( A ) preparation of inter-mediates ; (B) synthesis of biotin isomers.( A ) Dieckmanii cyclisation of esters (XVIII; R’ = C0,Et or C0,Me)prepared from ethyl thioglycollate and a@-unsaturated esters gave mainly4-ketothiophan-3-carbovylates (XIX ; R’ = C0,Et or C0,Me) rather thanthe 5-isomers (XX).321 33 This was shown by the fact that the derivedacids (XIX ; R’ = C0,H) were identical with corresponding acids obtainedvia the unambiguous cyclisation of the appropriate cyanides (XVIII ;R’ = CN) to (XIX ; R’ = CN). Preparation of the 2-substituted thiophan-3 : 4-dicarboxylic acids (XXI) was completed along conventional lines :The double bond in (XXII) was shown to be in the 3.: 4-position by theobservation that the same product could be derived from the structurallyestablished intermediate (XXIII). The synthesis of (XXI ; R =[CH,I4*CO,H) by the above route proved highly unsatisfactory, however,since in this case (XX; R = [CH&*CO,Me) (actually the 5-methyl ester)was the main product from the Dieckmann cy~lisation:~~ Attempts toconvert the compound (XXI; R = [CH,],*OPh) via the bromide (R =32 B.R. Baker, M. V. Querry, S. R. Safi, and S. Bernstein, J. Org. Chem., 1947, 12,33 G. B. Brown, B. R. Baker, S. Bernstein, and S. R. Safir, ibid., p. 155.34 G. B. Brown, M. D. Armstrong, A. W. Moyer, W. P. Anslow, junr.,.B. R. Baker,138.M. V. Querry, S. Bernstein, and S. R. Safir, ibid., p. 160222 ORQANIC CHEMISTRY.[CH,],*Br) into (XXI; R = [CH,],*CO,H) also failed, as did attemptsfrom the corresponding urethane, for the reasons indicated : 32(XXI; R = [CH,],*OPh) -> HBr ';;l-F..Curtius Br- \CH,* H,2Br- .1Et0,Q Q02EtNH NH N - , N+K, $H3 dH2-vH2-----+ + t--= (7%\ s r C H 2HBr H k- *[CH213*oph \ s r C H 23Br-+ \CH,*bH,However, synthesis of (XXI; R = [CH,],*CO,H) was accomplished insatisfactory overall yield starting from pimelic acid, the derived triester(XXIV) on Dieckmann cyclisation giving the required intermediate (XIX ;R = [CH,],*CO,H, R' = CO,Me), and not the cyclohexanone (XXV).35The acids (XXI) as initially obtained were mixtures of isomers, but ineach of the cases (R = Pry [CH,],*OPh, [CH,],*CO,H) a single racematehaving a tra?zs-C,-C, configuration readily crystallised from the mix-t ~ r e , ~ , , ,,, 35 and the residue could be made to yield more of the sameracemate by esterification and treatment with methanolic sodium methoxide(to invert the corresponding cis-racemate) .329 35 The trans-configurationof each acid was shown by stability to heat, formation of di-acid chlorides,etc.Conversion into the cis-isomer was achieved by heating under refluxwith acetic or propionic anhydride, followed by 339 36 Thetrans-di-acids (XXI) were converted via the dimethyl esters and hydrazides,and using the Curtius reaction, into the trans-diamines (XXVI). Thecis-esters, however, also afforded the trans-di-acid hydrazides so that thecis-diamines could not be obtained, by this route, or by other routes involv-ing simultaneous degradation of both carb0xyls.~~9 33 Inversion on form-ation of acid hydrazides or azides had not previously been experiencedwith carbocyclic compounds, but the unusual behaviour was also shownby penthian derivative^.^'(B) It became apparent that, in order to preserve the configurations atC3 and C,, methods for the stepwise degradation of the carboxyl groupswould have to be used.The procedures were developed using first theunsubstituted di-&id (XXI; R = €€).36Application of these procedures to the intermediate (XXI; R =35 B. R. Baker, M. V. Querry, S. Bernstein, 8. R. Safir, and Y . SubbaRow, J . Org.36 B. R. Baker, M. V. Querry, S. F. Safir, W. L. McEwen, and S. Bernstein, ibid.,37 B. R. Baker and F. Ablondi, ibid., p. 328.Chem., 1947,12, 167.p. 174ELVIDGE : HETEROCYCLIC COMPOUNDS. 223[CH,],*CO,H) led to (&)-biotin and (-~-)-epiaZlobiotin.~~ The chemical andstereochemical configurations of the intermediates were checked a t criticalc + t- (XXI; - R = H)(XXVII.)vO*NHPh J3°2Me (XXVIII.)/*\co co CO*NHPh C/O*NHPhNH NH*CO,Et NH CO*NH*NH2R = H) + EbOH I MeOHJ.(XXIX.)c- (XXVII) Ph*NH*CO CO\/ \c- (XXVI; '- (xxvlll) '- (xxlx) -2 ,."-r* R = H) + EtOH[ t = trans, c = cis, (i) = +COCl_3 CON, +NCO, (ii) = +CON,+ NCO.]stages, e.g., a t (XXX), by chemical methods. It will be observed thatinversion a t C, was effected during stage (XXXI) -+ (XXXII) and againduring stage (XXXII) + (XXXIII) so that the C,-acid, correspondingto the ester (XXXIII), was identical with (XXXI).Of the known biotin racemates, ( f)-allo- and (A)-epiallo-biotin bothgive microbiologically inactive dethiobiotin (XXXIV) and must con-sequently have the same configurations about C3-C,.(&-)-Biotin givesrise to an active dethiobiotin and ( A)-epibiotin would also afford the sameisomer. The melting point of the trans-product t-(XVII) corresponded tothat of the (&)-epiallobiotin of S. A. Harris et al.,39 and was identified withcertainty by Raney-nickel desulphurisation to a biologically inactive pro-duct : thus t-(XVII) could not have been the unknown (&)-epibiotin. Atrans-configuration for the C3-C, link in (&)-epiaZZo- and ( f)-allobiotinwas thus rigidly establi~hed.~~ The cis-product c-(XVII) had 60% of theactivity of natural biotin in assay against L. arabinosus, and resolution withL-arginine yielded (+)-biotin, identical with the natural vitamin.Itfollowed that the remaining, unknown racemate, (&)-epibiotin, was also acis-isomer, necessarily epimeric with ( &)-biotin a t C,.and Y . SubbaRow, J . Org. Chem., 1947, 12, 186.J . Amw. Chem. SOC., 1944, 66, 1800.38 B. R. Baker, M. V. Querry, W. L. McEwen, S. Bernstein, S. R. Safir, L. Dorfman,39 S. A. Harris, R. Mozingo, D. E. Wolf, A. N. Wilson, G. E. Arth, and K. Folkers224 ORGANIC CHEMISTRY.Bemuse the synthetic methods enabled the configurations a t C, and C,to be inverted selectively, a synthesis of ( f)-epibiotin became possible.4o Itt- (XXI)YO*NHPh vO*NHPhNH C0,Me NH C0,H.1Me0,C C0,Me H0,C C0,Met- t - R l NaOH t- dR,l *t- dR,f 3 t- d.(XXX.) (XXXI.)k % OYOONHPh YO-NHPh VO-NHPh Y O-NPhNH NH*C02Me NH CO*NH*NH, NH C02Me NH bo(ii) MeOHt- ‘ d R t- U R f<NH,x t- F I R + = c- b { RI (XXXII.) (XXXIII.)\S/+t- (XXVI.) cooll,coNH NH/ \Me l - i CH,Rc- (XVII.) YO-NPh(*)-biotin NH 60 + Ic- (XXVI.)t- (XVII.)(&)-epiaZbbiotin(XXXVII .)YO-NHPhPh*NH*CO COC-was apparent that the trans-racemate (XXI; R = [CH,],*CO,H) could haveeither of the total configurations (XXIa) or (XXIb). By inversion at C,and C, as indicated, both of the possible cis-C,-C, racemates of biotin,(XVIIa) and (XVIIb), were obtainable irrespective of whether the actualconfiguration of the starting material was (XXIa) or (XXIb). Now in theprevious reaction sequence a cis-configuration had been obtained by inver-sion a t C, during the stage (XXXI) + (XXXII).If instead, a cis-40 B. R. Baker, W. L. McEwen, and W. N. Kinley, J . Org. Chem., 1947,12, 322ELVIDGE : HETEROUYCLIC COMPOUNDS. 226configuration were obtained by inversion at C,, a t a suitable stage, the endproduct would, as already indicated, then be epimeric with the product(XXIU.)c,+ - invert c, f- - iriver t c, + - c,+- -- c, (3,-+ -y--+ c3-+c4+ - c4+ - c4 - +(XVIICC.) (XVIIb . )'2 - + invert '2 - + invert c2 - + c3-+ - c3-3- -- c,+-c, - + c4+ - c4+ - C' c*(XXIb.)previously given, i.e., it would be (f)-epibiotin. The correctness of thisreasoning was demonstrated by the synthesis of ( 5)-epibiotion c'- (XVII)as follows, the structures of intermediates being proved where necessary :t- (XXX) THPh YHPh(XL.) (XXXVIII.)c'- (XXVI) c'-(XVII)( f )-epibiotin(R, R', R" as previously.)It is to be noted that the reagents used for effecting the stage (XXXV) -->(XXXVI), vix.acetic anhydride-sodium acetate, caused inversion a t C4but not a t C,. Already established was the fact that in the Curtius re-arrangement of an azide to an isocyanate no inversion occurred except whentwo adjacent carboxyls, attached to the thiophan (or penthian) nucleus,were degraded simultaneously. The need to convert the C, side chaincarboxyl into anilide as a t (XXXVII) 38 and (XXXVIII) 40 was occasionedby the fact that otherwise partial inversion took place a t C3 and C4, re-spectively, during the subsequent conversions into the acid hydrazides(XXXIX) and (XL). The primary effect of introducing the anilide groupwas to reduce very markedly the solubility of these compounds in thereaction medium.REP.-VOL. XLV, 226 ORGANIC UEPMISTRY.To reiterate briefly, it is apparent that a configurational change can beeffected selectively a t nuclear substituents as follows : (a) a t a carboxylby boiling acetic or propionic anhydrides; ( b ) a t an ester group by boilingalcohol containing a trace of sodium alkoxide; ( c ) a t an anilide group byboiling acetic anhydride containing sodium acetate.Peculiar to thethiophan (and penthian) systems, and directionally uncontrollable, are (d)the inversion a t one of two adjacent nuclear carboxyls during their simul-taneous Curtius degradation via acid chlorides and sodium azide, and (e)the inversion a t one of two adjacent ester groups during their conversionwith hydrazine into acid hydrazides.Pterins.Since work in this field was previously reviewed*l progress has becnmade inseveral directions : new syntheses of vitamin B, (pteroylglutamic acid) and ofpteroic acid have been devised ; the structure of the fermentation Lactobacillusm e i factor has virtually been established; a new microbial growth factor,rhizopterin, has been isolated, identified, and synthesised ; some experi-ments concerning reduction of the pteridine nucleus are reported; and acontinued interest has been shown in the preparation of pteridine deriv-atives generally. .Results previously announced in a preliminary manner,e.g., the deduction of the structure and the synthesis of the liver L.caseifactor (vitamin B,) have now been established by the publication of fullchemical details.42, 43, 449 45, 46 Details of the method of isolation andpurification of this factor have also been disclosed.47 The precise natureof the anti-anEmia factor, " folic acid ", originally obtained from vegetablesources by H. K. Mitchell and his co-workers 48 remaiiis undeterminedthough evidence increasingly points to its being a mixture of closely relatedcompounds with differing physiological activity.49 On the other hand, a" norite eluate factor " isolated from liver and yeast in 1940,50 is, according41 Ann. Reports, 1946, 43, 250.* A suggestion (M. Gordon, J. M. Ravel, R. E. Eakin, and W. Shive, J . Amer. Chern.Soc., 1948, 70, 878) that pteroyl derivatives function as carriers of formate (cf.thestructure of rhizopterin) in the biosynthesis of purines, possibly being involved in theinsertion of a single carbon unit into the pyrimidine ring, must be regarded with extremecaution since the evidence adduced in its support consists of microbiological experimentswith this “methylfolic acid.” Later work (W. Shive, J. M. Ravel, and R. E. Eakin,ibid., p. 2614; W. Shive, J. M. Ravel, and W. M. Harding, J . Biol. Chem., 1948, 176,991) seems to afford no substantiation234 ORGANIC CHEMISTRY.NH,, R, = OH), and 2 : 6-diamino- (LVII; R, = R, = NH,) derivativeswith glyoxal and diacetyl, and in addition, by reaction of the latter pyrim-idine with benzil, phenanthraquinone, and acenaphthaquinone, haveprepared a series of symmetrically 8 : 9-disubstituted pteridines :W.Steinbuch 77 condensed (LVII; R, = R, = NH,) with mesoxalic esterand saponified the product to obtain 6-aminoisoxanthopterincarboxylicacid (LVI; R, = R, = NH,, R, = CO,H, R, = OH). A similar reactionwith (LVII; R, = R, = OH) provided the hitherto inadequately describeddeaminoisoxanthopterincarboxylic acid (LVI ; R, = R, = R, = OH ; R, =C0,H). It is to be noted incidentally that the nomenclature of some ofthese products could be improved. Diacetyl, phenanthraquinone, andacenaphthaquinone have also been condensed with 4 : 5-diamino-6-hydroxy-2-ethylthiopyrimidine (LVII; R, = SEt, R, = OH) to give three new2-ethylthiopteridines (LVI; R, = SEt, R, = OH). 6 : 8 : 9-Trihydroxy-2-mercaptopteridine was prepared by G.B. Elion et from the mercapto-pyrimidine (LVII; R, = SHY R, = OH) and oxalic acid. These workersfound also that, contrary to the results of 0. I ~ l a y , ~ ~ reduction of 2-chloro-5-nitro-4-aminopyrimidine can be effected by an excess of alcoholic potassiumhydrogen sulphide to yield 4 : 5-diamino-2-mercaptopyrimidine (LVII ;R, = SH, R, = H). Condensation of the latter with glyoxal then afforded2-mercaptopteridine (LVI; R, = SHY R, = R, = R, = H) itself.A number of aminohydroxypteridine mono- and di-carboxylic acids andmethyl esters (LVI; R, = OH or NH,, R, = OH or NH,, R, = H, CO,Me,or CO,H, R, = COzMe or C0,H) have been prepared by C. K. Cain andhis collaborators 8O for testing as microbial growth factors and for studieson growth and hsmoglobin formation in chicks. The acids were obtainedfrom the corresponding (known) 9-methyl- (R, = H, R, = Me) and 8 : 9-di-methyl- (R, = R, = Me) pteridines by oxidation in alkaline solution withpotassium permanganate, and were converted into the methyl esters withmethanolic hydrogen chloride.It was observed that a carboxyl group inthe 8-position is less stable than in the 9-position of the pteridine nucleus,for on heating the 8 : 9-dicarboxylic acid (LVI; R, = R, = OH, R, = R, =C0,H) in quinoline monodecarboxylation to the 9-carboxylic acid (LVI ;R, = R, = OH, R, = H, R, = C0,H) took place.The potentialities of sugars and related compounds for the synthesis ofpteridines from 4 : 5-diaminopyrimidines have been investigated by P.Karrer7 7 Helv. Chim. Acta, 1948, 31, 2051.78 G. B. Elion and G. H. Hitchings, J . Amer. Chem. SOC., 1947, 69, 2553.79 Ber., 1906, 39, 250.80 C. K. Cain, M. F. Mallette, and E. C. Taylor, junr., J. Amer. Chem. SOC., 1948,'SO, 3026ELVIDGE : HETEROCYULIC COMPOUNDS. 235and his co-workers.81 By performing the reaction under carbon dioxide inboiling water containing a little acetic acid, pteridines were prepared from2 : 4 : 6-triamino-6-hydroxypyrimidine (XLI) and the aldoses, arabinose,xylose, glucose, galactose, and glyceraldehyde. The configuration of theproducts was not a t first rigidly established, but it was suggested that theywere probably 9-hydroxyalkylpteridines (LVIII) (e.g., R = CH2*OH in thecase of reaction with glyceraldehyde) formed in the following way :The ketose, fructose, gave a different product from glucose, so that, onthe preceding ideas, it was formulated as the isomeric 2-amino-6-hydroxy-8-~-arabotetrahydroxybutylpteridine (XLV ; R = [CH*OH],*CH,*OH).Thespectra of the pteridines from glucose and glyceraldehyde were closelysimilar to one another, but differed from the spectra of the products fromfructose and dihydroxyacetone.H. G. Petering and D. I. Weisblat 82 in a preliminary report stated, inagreement, that under Karrer's conditions D-glucose reacts with (XLI) to formthe 9-D-arabotetrahydroxybutylpteridine (LVIII ; R = [CH*OH],*CH,*OH),whereas D-glucosone a t pH 5-0 yields mainly the %isomer. These authorsfound in addition that in strongly acid solution both these two reactionsproceeded in the opposite senses since mixtures Were obtained richer in theisomer of the product previously isolated (h,, glucose gave the %isomer ;glucosone the 9-isomer).Following up their initial experiments, Karrer and Schwyzer 56 sub-stantiated their ideas that aldoses condensed with the pyrimidine (XLI)to yield 9-substituted pteridines, whereas ketoses gave the 8-isomers.Thusit was shown thet the product from (XLI) and dihydroxyacetone [evidently(XLV ; R = CH,*OH)] when condensed with p-aminobenzoyl-L-glutamicacid afforded a product containing 15% of vitamin B, (an 8-substitutedpteridine). A similar reaction with the 9-hydroxymethylpteridine derivedfrom (XLI) and glyceraldehyde, on the other hand, gave rise to no micro-biological activity, though a modification in which (XLI) , p-aminobenzoyl-L-glutamic acid, and glyceraldehyde ditoluene-p-sulphonate were condensedin the presence of potassium iodide led to a product containing 6% of thevitamin.81 F.Karrer, R. Schwyzer, B. Erden, and A. Siegwgrt, Helu. Chim. Acta, 1047,@a J. Amer. Chem. Soo., 1947, 09, 3566.30, 1031236 ORQANIC CHEMISTRY.Independently of Karrer et al., H. S. Forrest and J. Walker 83 hadtreated D-glucose and D-fructose with 2 : 4 : 5-triamino-6-hydroxypyrimidineand obtained from each condensation the same product, which they sug-gested was probably 2-amino-6- hydroxy- 8-D -arabotetrahydroxybutylpter-idine (XLV ; R = [CH*OH],*CH,*OH).However, P. Karrer and R.Schwyzer 84 pointed out that the reaction conditions involved the presenceof phenylhydrazine. Since glucose and fructose both give the same phenyl-osazone, it was to be expected that under such conditions the same pteridinewould arise from each sugar. There was no doubt that in the absence ofphenylhydrazine different products were formed.Since in the structural determination of the liver L. casei factor the 8- and9-methyl- and -carboxy-pteridines, (XLV ; R = Me and C0,H) and (LVIII ;R = Me and CO,H), were prepared and characterised unambiguously,44 itwill in future be a simple matter to orientate pteridine products whicharise from ambiguous condensations. Thus Forrest and Walker 57 haveshown that the product from reaction of 2 : 4 : 5-triamino-6-hydroxy-pyrimidine (XLI) with reductone and methyl p-aminobenzoate is mainlypteroic ester (an 8-substituted pteridine) since aerobic alkaline hydrolysisyielded 2-amino-6-hydroxypteridine-8-carboxylic acid (XLV ; R = C0,H).Independently, H. J.Backer and A. C. Houtmann 85 had suggested thatthe reaction between reductone and the same pyrimidine (XLI) producedthe 9-hydroxymethylpteridine (LVIII; R = CH,*OH) by analogy with thebehaviour of methylglyoxal. Clearly though, analogies are unreliable inthis field.The condensation of methylglyoxal with 4 : 5-diamino-2 : 6-dihydroxy-pyrimidine (LIX) had earlier been shown by J. Weijlard et aZ.86 to yieldonly 2 : 6-dihydroxy-9-methylpteridine (LX), since degradation gave noneof the known 2-amino-5-methylpyrazine.Subsequently, Cain et aLso haveconfirmed the structure (LX) in a more positive manner by degradingthe substance to the known 2-amino-3-carboxy-6-methylpyrazine (LXI) :MeGO.CHOI____, 4 H02C/NN NH2(flh!le(LXI.)In this connection it is of interest that pyruvic acid condenses with 2 : 4 : 5-triamino-6-hydroxypyrimidine to yield both of the theoretically possibleproducts : 78OH OH83 Nature, 1948; 161, 308.86 Rec. Truv. chim., 1948, 67, 260.86 J. Weijlard, M. Tishler, and A. E. Erickson, J . Arne?. Chem. Soc., 1945, 67, 802.a4 Helv. Chim. Acta, 1948, 31, 782ELVIDQE : HETEROCYCLIC COMPOUNDS. 237In boiling B~-sulphuric acid 9-methylxanthopterin (LXII) is formed, whilstin dilute acetic acid a mixture results, containing 8-methylisoxanthopterin(LXIII). This behaviour is comparable with that of glucosone (see earlier).Recently, the variously-reported preparations of hydroxymethylpteridineshave been questioned. According to R. B. Angier and his co-workers *'the condensations in 6~-hydrochloric acid of glyceraldehyde, s-dichloro-acetone, 2 : 3-dichloropropaldehyde (cf. reaction of the dibromo-compounda t pH 4), and a-bromotetronic acid (presumed to hydrolyse to 1-bromo-3-hydroxypropan-2-one) with 2 : 4 : 5-triamino-6-hydroxypyrimidine(XLI) all lead to 2-amino-6-hydroxy-9-methylpteridine (LXIV), and notto the expected 9-hydroxymethyl or -halogenomethyl compounds (LXV).Similarly ethyl ccy-dibromoacetoacetate reacts with (XLI) to give, aftertreatment with alkali, 2-am'ino-6-hydroxypteridine-8-acetic acid (XLV ;R = CH,*CO,H) instead of a bromo- or hydroxy-acetic acid derivative.It is suggested that intermediately-formed dihydropteridines such as (LXVI)aromatise by loss of the elements of water or hydrogen halide (as the casemay be) rather than by dehydrogenation :CHO(where X = C1 or OH)N/\/" OH /No;-Hx // /N\(Lxv.) NHJ\ ,,!I bH,X N I I , ! N / \ N p II I (LXIV.)N \N/There is, however, the possibility that under certain conditions oxidation ofthe dihydro-intermediate (LXVI) might take place preferentially, and asubstituted-methylpteridine (LXV) would then result. Further work isobviously required : especially is it desirable that better analyses beobtained for the alleged hydroxymethyl compounds. In view of the furtherreactions which have been achieved with these products there can be littledoubt that they are not pure methylpteridines, but their precise nature,e.g., whether they are mixtures containing (LXV) and/or (LXVI), is inneed of clarification.J. A. E.J. A. ELVIDGE. J. D. LOUDON.S. H. HARPER. J. F. W. MCOMIE.D. H. HEY. B. C. SAUNDERS.B. JONES.*' R. B. Angier, C. W. Waller, J. H. Boothe, J. H. Mowat, J. Semb, B. L. Hutchings,E. L. R. Stokstd, and Y. SubbaRow, J. Amr. Chem. SOC., 1948, 70, 3029

ISSN:0365-6217    

DOI:10.1039/AR9484500118

出版商:RSC    

年代:1948

数据来源: RSC

摘要:

BIOCHEMISTRY.1. INTRODUCTION.BIOCHEMISTRY is at present enjoying a period of unprecedented effluor-escence. So many and so varied are the fronts upon which knowledge inthe subject is advancing that it is difEcult to make a selection for articlessuch as those presented in these Annual Reports. A choice has never-theless been made which it is hoped will illustrate the progress being achievedwithin the subject itself and also in that regioh of contact between bio-chemistry and pathology to which Chemotherapy belongs.Advances in technique have frequently served as a powerful weaponand incentive-as in partitiorl chromatography and the study of proteinstructure reviewed below-but seldom, if ever, has the adoption of a methodof experimentation proved so revealing or so altered the established waysof thought in a science as has the use of isotopes in biochemistry.Therealisation of a dynamic equilibrium embracing the constituents of evenhighly differentiated structural tissueB such as bone has proved startlingindeed. Products such as uric acid, found in theexcreta, were formerly regarded as end stages of a series of chemical changesaffecting more complex body or food constituents from which source theyoriginated. Now, however, the realisation is borne in upon us that moleculessuch as those of uric acid are being continually synthesised from relativelyvery simple units, and continually broken down again. There is anoverall equilibrium, but the dynamic exchange is far more intense anddeep-seated than could have been realised without the use of labelledatoms.More and more significance is being attached to the part playedby small molecules in the biochemical exchanges of the cell.It used also to be thought and taught that, the more precise the inform-ation obtained concerning the detail of chemical reactions occurring in thebody, the more nearly were these seen to simulate happenings in the testtube. But the use ofisotopes has revealed reactions of carbon dioxide fixation and mechanismsfor the synthesis of such materials as the tricarboxylic acids for whichthere is no in vitro parallel. Elegant and beautiful in their achievement,they appear also to be of fundamental importance in the life of the cell.In directing attention to the lines of approach which are being exploredtoward a chemotherapeutic control of tuberculosis, the intention has beento emphasise a point too frequently overlooked : that it is the host-tissuerelationship which dominates the picture, the more particularly perhapsin this infectious disease than in others, and that the situation is one whichchemotherapy dare not afford to neglect and may even be able to exploitadvantageously in particular cases.The outstanding successes of chemotherapy have up to the presentBut not only that.Oxidation by dehydrogenation is a case in pointBENTLEY : SMALL MOLECULES I N BIOSYNTHESIS.239beenationledgevery largely results of happy accident, but it is possibly no exagger-to say that the era of rational approach, based upon a detailed know-of the biochemistry of both host and parasite, should hold incomparablybrighter promise for the future.C .R.2. THE FUNCTION OF SMALL MOLECULES IPJ BIOSYNTHESIS.With the greatly increased availability of stable and radioactive isotopes,their use is becoming less of a matter for the specialist laboratory. Manybooks are now available which describe and discuss thevarious techniques used in tracer studies. I n this Report, methods assuch will not be discussed; but rather an attempt will be made to discusssome recent work, largely but by no means exclusively carried out withtracers, which both indicates and influences the present trends of bio-chemical thought.Investigations with isotopes have helped to develop our ideas in threebroad directions. An almost immediate result of the extensive use ofdeuterium and 15N by the Columbia school was the concept of the “ dynamicstate ’’ of many body constituents.Cell components, such as proteins andfats, were shown to be in a state of continuous degradation and re-synthesis-a view which contrasts sharply with those generally held before 1935. Re-ferring to fat depots, R. Schoenheimer was able to say that “ contrary tothe general idea of the slow metabolism of fat tissues, all the experiments . . .point to the fact that the fat stores are very actively involved in the con-version processes characteristic of life.” Such experiments have abun-dantly justified and confirmed Hopkins’s far-sighted dictum-“ life is adynamic equilibrium in a polyphasic system.”A second development of the continued use of isotopic tracers led to theidentification of specific precursors involved in biosyntheses under normalphysiological conditions.Now that investigations have been extended tocover many cell components, it becomes apparent that the living organismvery often makes use of relatively simple chemical units for biosynthesis.For example, a compound such as carbon dioxide, formerly consideredalmost exclusively as an end product, takes part in a large variety of bio-and reviews“ Radioactive Tracers in Biology,” M. D. Kamen, Academic Press Inc., 1947;“ Symposium on the Use of Isotopes in Biological Research,” American Cancer Society,1947; “ The Use of Isotopes in Biology and Medicine,” University of Wisconsin Press,1948 ; “ Radioactive Indicators, Their Application in Biochemistry, Animal Physiology,and Pathology,” G.Hevesy, Interscience Publishers Inc., 1948 ; “ Preparation andMeasurement of Isotopes and Some of their Medical Aspects,” Supplement, U.S. NavalMedical Bulletin, March-April, 1948 ; “ Preparation and Measurement of IsotopicTracers,” D. W. Wilson (Editor), J. W. Edwards, Ann Arbor, 1946.D. Rittenberg and D. Shemin, “ Currents in Biochemical Research,” 1946, p. 261 ;M. D. Kamen, Ann. Rev. Biochem., 1947, 16, 631; J. Sacks, Ckem. Reviews, 1948, 42,411 ; B. Vennesland, Adv. BioZ. Med. Physics, 1948, 1, 45; N. S. Radin, Nucleonics,1947, 1, No. 1, 24; No. 2, 48; No. 4, 51; 1948, 2, No. 1, 50; No.2, 33.Harvey Lectures, 1937, 142240 BIOCHEMISTBY.synthetic reactions; or a compound such as uric acid, apparently an excre-tory product derived from a particular group of related substances, mayalso be continuously synthesised from very simple units. In contrast totheir normal chemical properties, these small molecules frequently exhibita remarkable lability in the living cell, and it is scarcely possible to con-sider biochemical reactions in terms of formal chemical equations involvingrelatively stable and identifiable intermediates. At present, it is notpossible to specify the actual nature of these highly reactive units. It ispossible that they are free radicals; or that they are activated by com-bination in a high energy bond, or by adsorption on enzyme surfaces.Whilst very similar units may be derived from different sources, such asfat, carbohydrate, or protein, there is evidence to show that they are notidentical.A third concept, the validity of which has been reinforced by isotopestudies, is that of group or radical transfer.Many enzyme systems havebeen discovered which catalyse the transference of a chemical unit fromone molecule to another. These transfer processes are possible with amino-and amidino-groups, methyl groups, acetyl groups, phosphate radicals, andhydrogen atoms. The importance of such reactions has, for example, beenappreciated in nutrition studies, and a supply of labile methyl groups isrecognised to be essential for full growth. Further transfer reactions maybe discovered, and this type of reaction seems to be widely used in syntheticprocesses.The general outlines of biosynthesis as they are at present understoodmay be summarised as follows.The breakdown of tissue and dietarycomponents, in addition to providing energy, furnishes a “ pool ” of meta-bolites, from which tissue components may be regenerated and excretoryproducts are derived. The metabolic “ pool ” has no physical reality, butmay be pictured in terms of the availability of newly formed small mole-cules. These small molecules, if isolated from tissues, would in generalbe stable compounds. In the cell, and in the presence of specific enzymes(themselves also presumably involved in the general dynamic state), theorganic molecule becomes an activated component of the dynamic processesof life. It will become part of a chain of continuous reactions (which arefrequently cyclic and mutually dependent) in which almost all body com-ponents, including the so-called storage materials, take part.The functionof these active small molecules has been emphasised by K. Bloch : “ bodyconstituents of high molecular weight are synthesised by condensation ofnumerous small-sized units rather than by the utilisation and rearrange-ment of preformed large molecules.” Whether a compound such as chol-esterol is formed by simultaneous condensation of the necessary C , and otherunits, or whether the synthesis involves a series of precursors of increasingmolecular weight, is still a major problem for the biochemist.The C, and C, compounds which have been most extensively investigatedup to the present time are carbon dioxide, acetic acid, and glycine.ExcellentPhysiol. Reviews, 1947, 27, 594BENTLEY : SMALL MOLECULES IN BIOSYNTHESIS. 241and comprehensive reviews on carbon dioxide and acetic acid have beenpublished, and in this Report only the more recent findings can be dis-cussed. A more complete account on glycine will be given; its functionin the biosynthesis of porphyrins and purines will be considered separately,but its more general properties will be first outlined.The Metabolic Activity of Glycine.The General Properties of Gbcine.-Although the metabolism of mostamino-acids has been investigated with isotopes, no single nitrogenousmaterial has yet been found to rival the intense reactivity of glycine inbiosyntheses.It seems likely that glycine has a rather special functionand is one of the fundamental small units used in biosyntheses. It isknown to participate in the biosynthesis of the following compounds : pro-teins, glutathione, creatine, ornithine, ethanolamine (and hence choline) ,uric acid, yeast purines, hzemoglobin (and possibly stercobilin), glycogen(almost certainly via serine), acetate (in DipZococcus glycinophihs), and.5(4)-aminoglyoxaline-4(5)-carboxyamide. Glycine can act as a detoxicant(e.g., in the formation of hippuric acid and nicotinylglycine), and there issubstantial evidence for the conversion of glycine into serine and proline inyeast.The ready incorporation of administered glycine (labelled with 15N)into the tissue proteins of animals was f i s t observed almost ten years agoby Ratner et aZ.' It was also shown, in these early studies, that labelledglycine was specifically utilised for the sarcosine moiety of creatine,* andthat glycine nitrogen was the precursor of the a- and 8-amino-groups ofornithine .gThe peptide, glutathione, of liver and intestine was found to incorporate15N from glycine more readily than did the proteins of the same tissues.lORecently, the in vitro uptake of glycine into the glutathione of isolated liverhas been studied.ll About 0.1-0.2 mg.of glycine was incorporated perhour per g. of liver, and a similar uptake was observed with acetylglycine.I n these in vitro experiments an uptake of 15N into the liver proteins wasalso observed, thus confirming earlier observations with radio-methionine, 12and 14C02,13 that proteins themselves can be regenerated by liver tissuein vitro.The in vitro uptake of 14C from glycine (labelled in the carboxylti H. G. Wood, Physiol. Reviews, 1946, 26, 198.K. Bloch, ibid., 1947, 27, 574.S. Ratner, D. Rittenberg, A. S. Keston, and R. Shoenheimer, J. Biol. Chem.,1940,134, 665.* K. Bloch and R. Schoenheimer, ibid., 1940, 133, 633.D. Shemin and D. Rittenberg, ibid., 1944, 153, 401 ; 1946, 158, 71.10 H. Waelsch and D. Rittenberg, ibid., 1941, 139, 761.11 K. Bloch and H. S. Anker, ibid., 1947, 169, 765.l2 J. B. Melchior and H. Tarver, Arch. Biochem., 1947, 12, 309.l 3 C.B. Anfinsen, A. Beloff, ,4. B. Httstings, and A. K. Solomon, J. Biol. Chem.,1947,168, 771242 BIOCHEMISTRY.and methylene groups) has been studied in rat tissue homogenates l4 byGreenberg and his co-workers. Their experimental work, particularly withrespect to possible contamination of the isolated materials, seems open tosome objections.From studies on 14C uptake &om glycine by the rat fcetus Greenberget al. have concluded that growth is the result of an increased activity ofprotein synthesis.15 On the other hand, D. Rittenberg and D. Shemin l6have suggested that the greater overall anabolic rate during growth is aresult of a relative decrease of degradative processes. In experiments byRittenberg and Shemin to test their hypothesis, rats were given a standardamount of 15N glycine after removal of about half of the liver.17 The rateof protein formation in the regenerating liver was not appreciably fasterthan that in normal animals.They concluded that in this case growthwas a result of the inhibition of degradative reactions.The mechanism of peptide bond synthesis has been extensively studied,and, now that an in vitro regeneration of protein has been observed, furtherwork will probably follow. The nature of the activated intermediatesinvolved is still almost completely unknown. A study of the related modelsynthesis of p-aminohippuric acid from p-aminobenzoic acid and glycinein rat liver slices has shown that this reaction is dependent on energy-yielding processes .la Evidence for this dependence was the stimulatingeffect of cytochrome c on the aerobic reaction, and the fact that underanaerobic conditions the reaction could be supported by the addition ofATP.These results strongly suggest that phosphorylated intermediatesare involved in this synthesis. No evidence has yet been obtained eitherto prove or to disprove the suggestion of D. Riftenberg and D. Shemin19that peptide synthesis may proceed via an acetylated intermediate. Aninteresting observation is the easy in-vitro formation of hippuric acid byreaction of dibenzoyl hydrogen phosphate with glycine.20 Sodium dibenzoylphosphate was more resistant to hydrolysis than the monobenzoyl com-pound, but the latter compound did not react with glycine under the'' physiological conditions " employed (pH 7.4, 37").With sodium di-benzoyl phosphate and glycine, half of the anhydride groups disappearedwithin a few minutes; the reaction has also been observed with ornithineand lysine. It was suggested that diacyl phosphates (or substituted deriv-atives) rather than monoacyl phosphates could be the intermediate activatedprecursors of peptide bond synthesis.Evidence for the participation of glycine in the biosynthesis of serinel4 F. Friedberg, T. Winnick, and D. M. Greenberg, J. Biol. Chem., 1947, 171, 441.l6 F. Friedberg, M. P. Schulman, and D. M. Greenberg, ibid., 1948, 173, 437.l6 " Current's in Biochemical Research," 1946, 272.l7 D. Rittenberg, E. E. Sproul, and D. Shemin, Fed. PTOC., 1948, 7, 180.lS P.P. Cohen rand R. W. McGilvery J. Biol. Chem., 1946, 166, 261; 1947, 169,lQ Ann. Rev. Biochem., 1946, 15, 247.ao H. Chantrenne, Nature, 1947, 160, 603; Compt. rend. Trav. Lab. Carlsberg, 1948,119; 1947, 171, 121.26, 297BENTLEY : SMALL MOLECULES I N BIOSYNTHESIS. 243and proline in yeast has been provided by Ehrensvard and hia colleagues.21Tordopsis utilis was grown with either m-alanine or glycine (both labelledas 13C02H) as the sole carbon source. With DL-alanine, the 13C was ratherevenly distributed amongst the various amino-acids, with an expectedmarked excess only in the alanine fraction. With glycine, however, laCwas transferred predominantly to the serine and proline fractions, Thisis a reversal of the well-known serine --+ glycine reaction, and it is possiblethat the proline may be formed analogously to the pyrrole ring of porphyrins(q,v.).There is also evidence for the in vitro conversion of glycine(NH2*14CHa*C02H) into serine in rat-liver homogenate.22 Experiments onthe formation of glycogen from glycine have now confirmed that an in V ~ V Qconversion of glycine into aerine can take place. Earlier experiments inwhich NH,*CH,*13C02H was fed to mice, showed that about 1% of theisotope was incorporated into liver glycogen.23 Glycine is believed not to bedeaminated to acetic acid in animal tissues (see p. 251), and it was suggestedthat glycine was incorporated into glycogen by a mechanism involving suc-cessive conversion into serine and pyruvate. Very substantial evidence thatthese reactions do take place was provided by the simultaneous administrationof NH,*CH,*13C0,H and HJ4C0,H to a rat.24 Glycogen and serine wereisolated and degraded so that individual carbon atoms could be identified.Serine contained 13C only in the carboxyl group ; and 14C almost exclusivelyin the P-position.Glycogen contained 13C only in the 3 and 4 positions,and to almost the same extent as the serine carboxyl. 14C was present inall the glycogen carbon atoms, but the specific activity in the 1 and 6 positionswag more than twice that of the 3 and 4 positions. These distributionsagree with the initial formation of pyruvate from serine, followed by itsreversible tranaforrnation to a symmetrical C, dicarboxylic acid (for fulldetails, see the paper by H.G. Wood, N. Lifson, and V. Lorber 25) :NH,dCH,*13C02H + H*I*CO,H 4 14CH2(OH)*CH(NH2)*13C02H -+14CH,*C0*13C02H14CH,*CO*lW0,H + CH3* 14C 0- I4C 02Hvia a symmetrical f 14CH3*C0*13C02H + 14'02 C, dicarboxylic acid (fumarate) \Hence there is a pathway for the conversion of glycine and formate intoglycogen via serine and pyruvate. (The reactivity of formate is of con-siderable interest. Its incorporation into uric acid was previously the firstwell-authenticated case of an animal biosynthesis involving formate. It ispossible that further work will show it to be utilised in other directions.)Although glycine is believed not to be deaminated to acetic acid in21 a. Ehrensvitrd, E. Sperber, E. Sraluste, L. Reis, and R. Stj6rnholm, J.Biol.Ba T. Winnick, I. Moring-Claesson, and D. M. Greenberg, ibid., 1948, 175, 127.14 W. Sakami, ibid., 1948, l?%, 995.25 Ibid., 1945, 159, 475.Chem., 1947, 169, 759.N. S. Olsen, A. Hemingway, and A. 0. Nier, dbid., 1943, 148, 611244 BIOCHEMISTRY.animal tissues, its anaerobic decomposition by Diplococcus glycinophilus doeslead to the accumulation of acetic acid : *4NH2*CH,*C02H + 2H20 ---+ 3CH,*C02H + 2C0,The reaction has been investigated with carboxyl- and methylene-labelled( 14C) glycine, 14C02, and CH3*14C02H.26 The following conclusions werereached. (a) 75% of the acetate methyl group and 54% of the acetatecarboxyl carbon are derived from the glycine methylene group ; 90-95%of the carbon dioxide evolved is derived from the glycine carboxyl group.The main reaction, therefore, is probably a condensation of two glycinemolecules through their methylene groups with either simultaneous orsubsequent decarboxylation.Direct reduction of glycine is also unlikelysince 6% of the acetate methyl carbon and 38% of the acetate carboxylcarbon are derived from 14C02. ( b ) Complete oxidation of glycine takesplace to a small extent only, and the acetate is subsequently metabolisedonly slowly (if at all). This probably rules out a mechanism which involves14C02 fixation via pyruvate and oxaloacetate (with a subsequent regener-ation of acetic acid).The Oxidution of Glycine.-As S. Ratner, V. Nocito, and D. E. Greenhave pointed the oxidation of glycine and the nature of its breakdownproducts in the body are not well understood.In two experiments, NH2*CH2*13C02H has been used to obtain inform-ation about this problem.Administratiofi of the labelled glycine to micewas followed by a 50% excretion of the 13C in respiratory CO, within 16hours.23 The same compound, however, was not decarboxylated in isolatedmammalian heart preparations.28The apparent resistance of glycine to oxidation in tissue-slice experimentshas often been observed. Ratner et aL2' have now described a glycine oxid-ase, present in the liver and kidney of all the animals examined, whichcatalysed the aerobic oxidation of glycine. The preparation contained26 H. A. Barker, B. E. Volcani, and B. P. Cardon, J. Biol. Chem., 1948, 173,27 Ibid., 1944, 152, 119.28 V.Lorber and N. S. Olsen, Proc. SOC. Exp. Biol. Med., 1946, 61, 227.* Note added in proof: By feeding NH,*14CH2*C02H to rats, D. B. Sprinson ( J . Biol.Chem., 1949, 178, 529) has shown that the methylene carbon atom of glycine can beutilised in the formation of both acetic acid and aspartic acid. In the acetate, bothcarbon atoms were derived from the labelled atom in glycine; in the aspartate, thea- and /I-carbon atoms were 2-5 times &s active as the carboxyl groups-which wereprobably derived from respiratory carbon dioxide. Two mechanisms were suggested.(a) Formation of glyoxylic acid, followed by condensation with glycine to a C, com-pound in equilibrium with aspartate. (b) Degradation of glycine to a labelled formicacid (or near derivative) and condensation of this with more glycine to u/3-labelledserine.Hence it was converted into pyruvate t o acetate and oxaloacetate. W.Sakami (ibid., p. 519) has provided evidence that the latter mechanism can operate inthe rat. Feeding NH2*14CH2*C02H to rats gave liver-serine containing 14C in bothu- and /3-carbon atoms. There was almost as much 14C in the p- as in the a-position,and under these conditions glycine was therefore a major source of formate.504BENTLEY : SMALL MOLECULES IN BIOSYNTHESIS. 245flavin adenine dinucleotide as co-enzyme ; the oxidation products wereglyoxylic acid and ammonia :NH2*CH2*C02H + $02 + CHO*CO,H + NH,.In tissue slice experiments (particularly with kidney slices) a rapid formationof oxalic acid from glyoxylic acid was observed.The Biosynthesis and Metabolism of Purines.-Tracer studies of thesynthesis of pyrimidines and purines have again emphasised the importantdirect participation of small molecules in the biosynthesis of more complexcompounds.The careful experiments of H.Ackroyd and F. G . Hopkins 29 had led tothe conclusion that histidine and arginine were purine precursors. Theseamino-acids were removed from the diet of young rats for some weeks duringwhich time the allantoin excretion decreased to 40--50% of its originalvalue. Restoration of one or both amino-acids to the diet brought backthe allantoin excretion almost to its original value. With no intention ofbelittling this work, the following quotation from their paper will emphasisethe changes which have taken place in biochemical thought.“ When ananimal is in a state of full nutrition, it does not follow that such a processas the synthesis of the purine ring would necessarily be much acceleratedor increased by mere increase in the supply of its raw material. Theaccepted distinction between endogenous and exogenous metabolism andthe recognised relative constancy of the former could scarcely hold werethis the case. We know, it is true, that a large increase of protein in thediet does affect purine metabolism; but an individual amino-acid fed inexcess of the immediate current needs of the tissues, as when it is addedto an already efficient dietary, will almost certainly be broken down onmore direct lines, even if it be a normal precursor of the purine (or other)synthesis in the body.”The results to be discussed have shown that some of the purine nitrogenis derived from a general metabolic pool, and that there are also a numberof specific precursors for purine synthesis.On feeding ammonium citrate(labelled with I W ) to pigeons and rats, there was a rapid incorporation of15N into the purines (adenine and guanine) and pyrimidines (thymine andcytosine) of the nucleic acids in internal organs, excretory uric acid, andallantoin; 30 the liver incorporated isotope more actively than the otherorgans. Since nitrogen can be derived therefore from a general pool, purineexcretion is not reduced by restricting dietary nitrogen to protein sources.This observation also corroborates the conversion of the nitrogen of amino-acids into purines.I n these experiments the pigeon did not utilise ureafor purine synthesis. The uptake of 15N by histidine, in rats, was confinedto the cc-amino-group, strongly suggesting that its glyoxaline ring was notinvolved in purine synthesis. (Later studies have shown conclusively that29 Biochem. J., 1916, 10, 551.3O F. W. Barnes and R. Schoenheimer, J. Bid. Chew., 1943, 151, 123.s1 K. Bloch, ibid., 1946, 165, 477246 BIOCHEMISTRY.labelled L-arginine 32 and L-histidine 32 are not, in fact, purine precursors:)When guanine was isolated, the 2-amino-group as well as the ring nitrogenwere found to have taken up 15N.When guanine (containing 15N in the 2-amino-group, and 1 and 3 nitrogenatoms) was fed to rats, practically no isotope was incorporated into tissuepurines or pyrimidines; it was excreted mainly as allantoin, and to analmost insignificant extent as urinary ammonia and urea.35 Results obtainedwith pigeons were similar, most of the 15N being excreted in uric acid.Similarly, the feeding of isotopic pyrimidines (uracil and thymine) to ratsproduced 15N only in urinary ammonia and urea ; non-incorporation intoallantoin excluded the conversion of pyrimidines into purines.Orotic acid(uracil-4-carboxylic acid) has, however, been shown to be a precursor ofpyrimidines in the rat, being utilised in the biosynthesis of both uraoil andoyto~ine.~~a Recently, G . B. Brown, P. M. Roll, and A. A. Plentl haveobserved the incorporation of dietary adenine into tissue purines ; 34 adenine(labelled with I5N in the 1 and the 3 position) was fed to rats and was foundto be incorporated into nucleic acids, not only in adenine (13.7% replace-ment of tissue adenine in 4 days) but also guanine (8.2% replaoement).ATP contained a small but definite excess of W, and was formed moreslowly from dietary adenine.The excreted allantoin contained much moreJsN than the tissue purines, and it is possible that there are separate path-ways for the conversion of dietary adenine into tissue purines and excretoryallantoin. In confirmation of the earlier experiments, urinary ammoniaand urea contained only small amounts of isotope, and the non-incorporationof dietary guanine was again observed by these workers.The reason forthis curious discrepancy is obscure, but perhaps guanine is not incorporatedbecause of a specificity of the nuclear membrane. The formation of guaninefiom adenine took place with retention of the purine skeleton. 2 : 6-Diaminopurine was postulated by Brown as a possible intermediate in theconversion of adenine into nucleic acid guanine. The compound wassynthesised containing 15N in the 2-amino-group and in the 1 and the 3position of the ring; it was found to be an effective precursor of guaninein the rat.35Other experiments haye shown that in viwo the adenylic acid of skeletalmuscle is subject to a very rapid deamination-reamination reaction ; 3615N was administered to rats as ammonium citrate, and adenylic acid wasisolated.By decomposition with adenylic acid deaminase, it was shownthat practically all of the incorporated 1SN was in the 6-amino-group7 withlittle or no 15N in the ring. The rate of rejuvenation was comparable toC. Tesar and D. Rittenberg, J. BioE. Chern., 1947, 1'70, 35.33 A. A, Plentl and R. Schoenheimer, ibid., 1944, 158, 203.33a S . Bergstram, H. Arvidspn, E. Hammarsten, N, A. Eliasson, P. Rsichard, andH. v. Ubisch, {bid., 1949, 177, 495.34 Fed. Proc., 1947, 6, 517.36 A. Bendich and G. B. Brown, J . Biol. Chem., 1948, 176, 1471.36 H. M. Kalckar and D. Rittenberg, ibid., 1947, 170, 465BENTLEY : SMALL MOLECULES IN BIOSYNTHESIS. 247that of the amido-nitrogen of glutamic acid, suggesting that such amidesmay be involved in the reaction.Degradation of uric acid.37Alkaline MnO, AlloxanOHHydroxyacetylene diureidecarboxylic acidAcid(1) NH--,,CH--7-;iNHI I IAlloxantinI .1(2) co (81 coI(3) NH, (4) CO,H (9) NH,Allantoic acidHydrolysisNH, cwCHO I IUrease(2) CO,(2.8)co + (4) C02H INH2Glyoxylic acid UreaUrease J, Scheme 1.(2.8) c0237 J.C. Sonne, J. M. Buchanan, and A. M. Delluva, J. Biol. Chem., 1946, 166, 395;J. M. Buchanan and J. C. Sonne, ibid., p. 781; J. C. Sonne, J. M. Buchanan, andA. M. Delluva, ibid., 1948, 173, 69, 81248 BIOCHEMISTRY.Studies, more especially of the carbon skeleton of uric acid, have shownthat a number of other compounds may act as purine precursors; theincorporation of lactate (labelled with 13C in the CL- and p-atoms or with 13C inthe carboxyl group), CH3*l3CO2H, H*13C02H, 13C02, and NH,*CH,J3C02Hinto uric acid has been observed in pigeons.By use of the scheme ofdegradation outlined in Scheme 1, it has been possible to work out thecontribution of these compounds to specific atoms of the purine ~keleton.~'The following statement and the " reconstructed " uric acid molecule(Scheme 2) summarise the observed facts.(Respiratory CO, derived from (1)N-C f- Coz"3 carboxyl groups of acetate,lactate, and glycine)(7P, (8) ? (8)I I (As for 8) H-CO,H + (2)C 1 (::lT);yC +- H*C02H +--- CH,-CO,HI (7) CH3!8H( OH)-CO,H+ (3) N-- -- + II (5) CH,*NH2CH3*8H(OH)?!02H (4) C0,H1' IJ.( 5 ) (4) CH3*CO*C02H -+ CH2( OH)*?H.#H,I(4) C0,HThe glycine fragment is indicated by the heavy type.Nitrogen atoms1, 3, and 9 are from non-specific nitrogen sources.Xcheme 2.Carbon a t m 2 and 8 ;(i) Both have a common source, and can be derived from the formatecarboxyl (72 yo incorporation), acetate carboxyl (35% incorporation), andthe a- (or p-) carbon atom of lactate.(ii) The incorporation of the lactate carbon atoms probably arisesfrom the fact that they can give rise to acetate carboxyl.(iii) The relatively higher utilisation of formate suggests that it (or anear derivative) is the direct precursor, and is derived from acetate.(iv) Carbon dioxide (and lactate carboxyl) are not utilised for theseureide carbons and are not therefore formate precursors (cf. bacteria).(v) The utilisation of formate in avian metabolism is a notable dis-covery; very little respiratory 13C0, was produced from the HJ3COzH.Carbon atom 6 :(i) The carboxyl carbons of acetate, lactate, and glycine, as well as(ii) The isotope content of this atom closely parallels that, of respiratorycarbon dioxide, are incorporatedBENTLEY : SMALL MOLECULES I N BIOSYNTHESIS.249carbon dioxide, indicating that, only carbon dioxide is involved in its bio-synthesis.(iii) Formate is not utilised.Carbon atoms 4 and 5 :(i) Glycine carboxyl is utilised to a large extent for position 4, andlactate carboxyl less so.(ii) Carbon dioxide, acetate carboxyl, and the a- and p-carbon atoms oflactate are utilised only to a small extent for position 4. The connectionwith respiratory carbon dioxide indicates utilisatian through carbon dioxide.(iii) Carbon atom 5 is derived from the a- and the p-carbon atom oflactate.Nitrogen atoms :The utilisation of the glycine carboxyl (position 4) in conjunction withthe results of other experiments, provides evidence that the nitrogen atomof glycine can be utilised for the synthesis of uric acid in pigeons.It hasalso been shown that the nitrogen of glycine is a specific precursor of uricacid in humans,,* and that it is utilised only for the 7 position. The 1, 3,and 9 nitrogen atoms are derived from a non-specific source. A similarfinding has been reported for the guanine derived from yeast nucleic acids.39It now seems almost certain that the C-C-N unit in uric acid is derivedfrom glycine; the feeding of a doubly labelled glycine would be of valuein this connection.The role ofuric acid is seen to be much more diverse than previously supposed.Theutilisation of glycine for uric acid synthesis in both birds and man suggestsa, connection between its metabolism in these two species. The theorythat, in man, uric acid is the main degradation product of complex nitro-genous compounds (particularly purines), and in birds and reptiles theend product of protein metabolism, must be enlarged to include its synthesis,in birds and man, from several small molecules, and its anabolic aspectsmust be considered equally with its catabolic function.The conversion of carbon dioxide into uric acid does not appear to t'akeplace by any of the known assimilation reactions.The equivalent incor-poration of carbon dioxide and the carboxyl carbon atom of lactate (posi-tion 6) could have been explained as a result of the well-known reactions :CH,*CO*CO,H + 13C0, -+ 13C0,H*CH,*CO* 13C0211(4)-(6) (7)These facts lead to a number of interesting speculations.IJ.CH,*CH( OH)*13C0,H +--- CH,*COJ3C02HIf the possible incorporation of the lactate carbon atoms is considered interms of such a hypothesis, it can be seen that a 3 carbon chain (C-C-C)38 D. Shemin and D. Rittenberg, J . Biol. Chern., 1947, 16'7, 875.39 R. Abrams, E. Hammarsten, and D. Shemin, ibid., 1948, 173, 429.(6) (5)-(1250 BIOCHEMISTRY.can never be obtained where the carbon atoms are derived from carbondioxide (6), lactate or-carbon (Ti), and lactate carboxyl (4).It is suggestedthat the reactions :Lactate --+ pyruvate -+ serine --+ glycinemay take place. Serine is a known glycine precursor; and the (reverse)reaction, serine to pyruvate, has been described with B? coli, with otherbacteria, and in rat liver extract 40 (see also p. 243). The carboxyl anda-carbon atom of lactate would then become the same atoms of glycine, andthis would account for the observed distribution.The utilisation of formate, and the non-utilisation of carbon dioxide,for the 2 and the 8 carbon atom suggest that a reduced intermediate, e.g.,hypoxanthine, may be first formed. Hypoxanthine nitrogen is known tobe formed from ammonium salts by pigeon-liver slices, and this synthesisis stimulated by glutamine and oxaloacetic acid.41 The incorporation ofH*14C0,H and 14C0, into hypoxanthine has been observed in essentiallycell-free pigeon-liver h~mogenates.~~ The early stages of purine synthesismay involve a condensation of a diamino-compound with formio acid; sucha compound may be the diazotisable amine which accumulates in somebacterial cultures undergoing bacterio~taeis:~ and which has been identifiedas 5(4)-aminoglyoxaline-4(5)-carboxyamide.4 (Glycine has been shown tobe a precursor of this gly~xaline.~~) Condensation with formate (or acetate)by scheme 3 would complete the purine ring:’ but there is as yet‘ no con-crete evidence that tbe aminoglyoxalinecarboxyamide is the immediateprecursor.CO*NH, ICH II ,NH-CQN---C*NH,-NH -NH CO-NH I I I I III-.NHCHNN-C--NHC*CO,H -NI1-N -N--SJH I I oxidation I ICGH, --+ CCO,H 3CH -+ PH-k 00I I Scheme 3.Recent work 45a has, however, shown that dietary hypoxanthine andxanthine (labelled in the 1 and 3 positions with 15N) were ineffective as pre-40 E.Chargaff and D. B. Sprinson, J . Biol. Ohm., 1943,151, 273.4 1 A. Orstrom, 13. hstrom, and H. A. Krebs, Biochem. J., 1939, 33, 090.43 G. R. Greenberg, Arch. Biochem., 1948, 19, 337.43 M. R. Stetten and C. L. Fox, J . Biol. Chern., 1945, 161, 333.44 W. Shive et al., J . Arner. Chem. SOC., 1947, 69, 725.45 J. M. Ravel, R. E. Eakin, and W. Shive, J . Biol. Uhem., 1948, 172, 67.450 H. Getler, P. M. Roll, J. F. Tinker, and G. €3. Brown, ibM., 1949, 178, 259BENTLEY : SMALL MOLECULES IN BIOSYNTHESIS.251cursors of nucleic acids in rats ; these compounds were extensively convertedinto allantoin.One further conclusion must be mentioned ; feeding CH,-13C02H labelsthe 2 and the 8 carbon atom of uric acid, but not the 4 carbon atom.NH,*CH2*13C0,H, however, labels carbon atom 4, but not carbon atom 2or 8. The carboxyl group of glycine, therefore, cannot be directly utilisedin the formation of acetic acid, confirming earlier observations that glycineis glycogenic but acetate is not. As was stated previously this conversionof glycine proceeds via serine and pyruvate.Further Oxidation of Uric Acid.-In most mammals, uric acid is furtheroxidised to allantoin, and in man a further oxidation can also take place.The enzyme uricase which brings about the first oxidation is widely dis-tributed. It has been shown that an unstable, primary intermediate iafirst formed which decomposes non-enzymatically in three ways to hydroxy-acetylenediureide, allantoin, and uroxanic acid.46 Evidence was obtainedto show that the intermediate was a symmetrical compound; this hasbeen confirmed by experiments with a labelled uric acid.If the in vitrooxidation of uric acid (with 15N a t positions 1 and 3) (I) to allantoin takesplace via the symmetrical intermediate (11), subsequent cleavage of thering would give allantoin with 15N in the ring in one case, and in the ureidegroup in the other.C02HII I15NH-- co 15NH-C-NW-+ co 1 po I I CO C-NH15pJH-- C-NH(1.) dH (11.)II \cod-H-c--NH/This reaction was carried 0ut,~~a9 b and the allantoin further degraded (byoxidation to potassium oxonate, or reduction to hydantoin).These pro-ducts contained the same atom yo excess of 15N as the original allantoin,furnishing direct proof that the oxidation to allantoin did involve a sym-metrical intermediate such as (11). The oxidation of the uric acid withnitric acid or chlorine gave alloxan with atom yo excess of 15N twice thatof the parent uric acid. In this case, therefore, there was cleavage only ofthe glyoxalone ring. When this labelled uric acid was fed to rats, therewas again uniform distribution of isotope between the hydantoin and theurea portion of the urinary a l l a n t ~ i n . ~ ~ The in V ~ V O oxidation of uric aciddoes, therefore, proceed via a symmetrical intermediate.I n this experi-ment no 15N was found in visceral purines or urea, indicating that therewas no degradation of the ingested uric acid to ammonia or urea.46 F. W. Klemperer, J . Biol. Chem., 1946, 160, 111.47a L. F. Cavalieri, V. E. Blair, and G . B. Brown, J . Amer. Chem. Soc., 1945,70, 1240.47b L. F. Cavalieri and G. B. Brown, ibid., p. 1242.4 8 G. B. Brown, P. M. Roll, and L. F. Cavdieri, J . Biol. Chem., 1947, 171, 835252 BIOCHEMISTRY.The anaerobic breakdown of uric acid by Clostridium cylindrosporumyields carbon dioxide, ammonia, acetic acid, and glycine, and the reactionhas been studied in the presence of 14Co,.49 14C was incorporated into glycinelargely in the carboxyl group, and into acetate, where the methyl groupunexpectedly had more than twice the specific activity of the carboxylgroup.The low specific activity of the acetate carboxyl group indicatedthat it was derived largely from the fermented uric acid. The acetatemethyl carbon atom and glycine carboxyl group had similar activities andwere probably derived entirely from CO,. Glycine and acetic acid wereevidently formed by different routes.It is convenient to end this section by referring to some studies of urea.Although the ureide groups of uric acid may be derived from acetic acid,other experiments have shown that CH3*13C02H is not a precursor of ureacarbon in the rat.37 These ureide groups therefore have different origins.Early experiments in which liver slices were used, demonstrated that a tleast 50% of the urea carbon atoms were derived from bicarbonate (C0,).501 51In an elegant experiment, it has now been proved that the carbon atom ofurea is quantitatively derived from CO,.L-Methionine containing 14C inthe methyl group was fed to a rat.52 It was known that this group wasoxidised continuously to CO,, and that it therefore continuously labelledthe respiratory CO,. The latter, and urea, were collected over a 2-dayperiod; reaction of the urea with urease gave CO, for analysis. Despitethe fact that from the 1st to the 2nd day there was a 35% increase in ureaproduction and a 13% decrease in CO, production, the following figuresshow that there was an exact parallelism between the specific activitriesof the carbon atoms.Counts per min.per mg. C.1st day. 2nd day.Respiratory CO, ........................ 468 106CO, from urea, ........................... 465 102The incorporation of 14C0, into the carbonyl group of urea and citrullinehas been studied in washed rat-liver residue.53 The fixation into the lattercompound was of such a magnitude that citrulline must be considered tobe an obligatory intermediate of the Krebs' urea cycle. The conversionof citrulline (containing 14C in the carbonyl group) by liver homogenatesgave urea with the same specific activity. In recently reported experi-ments, the metabolism of 14C labelled urea has been studied after intra-peritoneal injection into mice.54 The urea was found to have a biologicalhalf life period of 5 hours; and all the radioactivity of the urine was dueto urea.About 20% of the injected 14C appeared in respiratory CO,.49 H. A. Barker and S. R. Elsden, J. Biol. Chenz., 1947, 167, 619.60 D. Rittenberg and H. Wadsch, ibid., 1940, 136, 799.61 E. A. Evms and L. Slotin, ibid., p. 805.62 C. G. Mackenzie and V. du Vigneaud, ibid., 1948, 172, 363.53 S. Grisolia and P. P. Cohen, ibid., 1948, 176, 929.54 E. Leifer, L. J. Roth, and L. M. Hempelmann, Science, 1948,108, 748BENTLEY : SMALL MOLECULES I N BIOSYNTHESIS. 253Whether this was due to a direct hydrolysis or to a reversal of the ureacycle has not yet been determined.The Biosynthesis of Porphyrins.-Before 1945 almost the only knownfact about porphyrin biosynthesis was that porphyrins could be synthesisedfrom protein derivatives.In 1940, it was stated that " between the absorp-tion of food and the appearance of porphyrins and porphyrin compounds inthe cells of the body and in excreta, there lies an unexplored and undoubtedlyimportant gap." 55 In 1945, K. Bloch and D. Rittenberg 56 fed sodiumdeuteroacetate to rats, and showed that deuterium was incorporated intothe haemin. Since the pyrrole rings of protoporphyrin do not contain ringhydrogen, this was only proof of the participation of acetic acid in sidechain formation, but it was the first time that a protoporphyrin precursorhad been identified. A little later, D. Shemin and D. Rittenberg 57 observed,in humans, that glycine could act as a specific nitrogenous precursor of thepyrrole rings in haemin. Many further results have provided a suggestionof the mechanism of porphyrin biosynthesis.Shemin and Rittenberg, in this first experiment, fed over a period of3 days the unprecedented quantity of 66 g.of 15NH2*CH2*C02H (containing32.4 atom yo excess of l5N) to a human adult. Blood samples were sub-sequently withdrawn a t intervals, and the 15N content of the isolated haeminand plasma proteins determined. The 15N content of the haemin roserapidly during the first 25 days of the experiment, and then remainedpractically constant (0.46 atom yo excess of 15N) to about the 95th day.The isotope content then declined, following an S-shaped curve. By con-trast the isotope concentration of plasma proteins (0.39 atom Yo excess onthe 4th day) had fallen to 0.13 atom yo excess by the 30th day.In further experiments designed to show whether glycine was used speci-fically, DL-leUCine, DL-glutamic acid, and DL-proline (all with 15N in theamino-groups) were fed to rats; 58 15N ammonium citrate was also fed forcomparison as a non-specific nitrogen source.The last two amino-acidswere of particular interest, since they were, on paper at least, possiblepyrrole precursors. After allowing for ammonia production from the un-natural isomers of leucine and proline (in the case of glutamic acid nocorrection was needed since D-glutamic acid is largely excreted), and cal-culating the results on the basis that the compound fed contained 100%of 15N, the following concentrations were found in the haemin samples.HEemin 15N%.Glycine .......................................0.93Ammonium citrate ........................ 0.09DL-Glutamic acid ........................... 0.17DL-Proline .................................... 0.18D L - L ~ u c ~ ~ ................................. 0.07These results show a direct utilisation of glycine for porphyrin biosynthesis,W. J. Turner, J . Lab. Clin. Med., 1940, 26, 323.5 6 J . Bwl. Chem., 1945, 159, 45.s8 D. Shemin and D. Rittenberg, ibid., 1946, 168, 621.6 7 Ibid., p. 567254 BIOUHEMISTRY.the other compounds examined being utilised only non-specifically. It hasalso been shown that L-histidine is not a, porphyrin precurs0r.~2The next step was the demonstration that the carboxyl carbon atomof glycine was not utilised for the porphyrin biosynthesi~.~~ WhenNH2*CH2*14C02H was fed to a dog and a rat, no activity was found in thehem fraction, although there was incorporation into the globin.Subsequentexperiments with appropriately labelled glycine (NH2J4CH2*C02H) showedthat the methylene carbon was incorporated.60 In this case the specificactivity of the isolated hemin was greater than that of the globin, thusshowing that the utilisation was a, specific process, independent of thegeneral labelling of biosynthetic intermediates with 14C. After implantationof Ca14C03 pellets in rats, a significant specific activity was found in hBm ;this suggests a utilisation of carbon dioxide for porphyrin biosynthesis, butthis evidence can only be regarded as a preliminary indication of such autilisation.Further evidence emphasising the importance of small biosyntheticunits rather than of large preformed structures has been obtained fromexperiments with yeast.62 When yeast was allowed to autolyse in thepresence of ammonium carbonate, a 95-fold increase of porphyrin formationwas obtained. The possibility was investigated that porphyrin-containingohromoproteins could be continuously synthesised and then split withexcretion of the intact porphyrin (whilst the amino-acid components reacheda dynamic equilibrium); but addition of cytochrome c, a peroxidase, orcatalase did not stimulate porphyrin production, although the compoundsadded were broken down.To further the study of porphyrin biosynthesis, work wa8 directedtoward finding an active in vitro system.The incubation of normal humanblood with 15N-labelled glycine was ineffective, but incorporation of glycineinto hem was observed on incubation of nucleated red blood cells (e.g.,duck A similar in vitro hmn synthesis was also observed usingblood from people having sickle cell an~emia.~~ An appreciable uptake of 14Cinto hzem wits later reported on in vitro incubation of rabbit bone marrowhomogenates with NH2-14CH,-C02H.65Evidence concerning the relative proportions of glycine involved in thesynthesis of each pyrrole ring of porphyrina was obtained by chemicaldegradation of hsemin obtained after feeding 16N glycine to a human.5* M. Grinstein, M.D. Kamen, and C. V. Moore, J . Biol. Chem., 1948, 174,6o K. I. Altman, G. W. Casarett, R. E. Masters, T. R. Noonan, and K. Salomon,61 W. D. Armstrong, J. Schubert, and A. Lindenbaum, Proc. SOC. Exp. Biol. Med.,62 J. E. Kench and J. F. Wikinson, Nature, 1945, 155, 579; 1946, 157, 730;63 D. Shemin, I. &I. London, and D, Rittenberg, J. Biol. Chem., 1948, 173, 799.64 Idem, ibid., p. 797.65 K. I. Altman, K. Salomon, and T. R. Noonan, ibkd., 1849,177, 489.767.ibicl., 1948, 176, 319.1948, 68, 233.Biochem. J . , 1946, 40, 660BENTLEY : SMALL MOLEUULES IN BIOSYNTHESIS. 255Eematoporphyrin dimethyl ether was prepared and oxidised to methylmethoxyethylmaleinimide and methyl propionylmaleinimide, a method whichgave unequivocal data with respect to the separation and identification ofthe two different types of pyrrole ring.66Haem (ferrous proto-porphyrin IX).Hzematoporphyrin dimethylether (0.113y0 excess 15N).* = CH2.CH2*C0,H IMe ~ CHMe*OMe + O - T L O\N/H(111) and (IV)(0.1 1 3 yo excess 15N).H(I) and (11)(O-112~o excess 15N).The former was derived from rings (I) and (11) ; the latter from rings (111)and.(IV).Their atom % excess of 15N was identical, and equal to that ofthe hzmatoporphyrin, showing that glycine was equally utilised in thesynthesis of the four pyrrole rings. It is probable that the pyrrole ringsare derived from a common precursor. A similar study has been madewith the labelled hzmin obtained after the feeding of 15N glycine toProtoporphyrin methyl ester was prepared, and the vinyl groups reducedwith hydrogen.Oxidation of the reduced porph yrin with chromic anhydridegave good yields of methylethylmaleinimide [derived from rings (I) and (II)]and methyl propionylinaleinimide [from rings (111) and (IV)]. Isotopeanalysis showed that the 15N content of these two compounds was idehtical.In this study it was also demonstrated that 15N ethanolamine was not adirect specific precursor.Speculation as to the mechanism by which the a-carbon atom and thenitrogen atom of glycine were used began with the suggestion by Sheminand Rittenberg that glycine was incorporated by initial condensation witha substituted p-keto-aldehyde (which could partly be derived from aceticacid). A formal analogy for this mechanism was provided by H.Fischerand E. Fink's variation of the Knorr pyrrole synthesis.68 Reductive con-6 8 Jonathan Wittenberg and D, Shemin, Cold Spring Harbor Symp., 1948, 13, 191 ;6 7 H. M. Muir and A. Neuberger, Biochem. SOC. Proc., 1948, 43, Ix.68 2. physiol. Chem., 1944, 280, 123.J . Biol. Chem., 1949, 178, 47256 BIOCIHEMISTRY .densation of acetoacetaldehyde diethylacetal and oximinoacetoacetic esterled to ethyl 2 -met hylpyrrole- 5 - carboxyla t e :It was further shown that formylacetone and glycine condensed to yield aproduct which gave a positive Ehrlich test for pyrroles; the product,however, was not isolated.Recent observations on the properties of pyruvoylglycine may be of interestfor porphyrin biosynthesis.On standing in alkaline solution, pyruvoylglycineunderwent an irreversible reaction characterised by the disappearance of theultra-violet absorption maximum a t 2400 A . ~ ~ The hygroscopic yellowish-white mass isolated did not have carbonyl properties. The pK of this substancewas identical with that of pyrrolidonecarboxylic acid ; the structure suggestedfor this compound was that of a hydroxypyrrolidone carboxylic acid :Hoe?= CH2 H O*7H--VH2CH,*CO,H --+ OC , ,CH*CO,Hoc\NH/ NHThe condensation of pyruvic acid with glycine at pH values of 5 to 6.3 hasalso been investigated, and it was reported that mixtures of various pyrroleswere formed.70 It is possible that such a condensation, rather than theFischer-Fink reaction, may be involved in this biosynthesis.It would beof considerable interest to determine whether the carbon atoms of acetatecan be used for pyrrole ring formation.If the porphyrin ring arises by cyclisation of pyrrole units (howeverthese may be formed) two further points must be considered.(i) Is the non-utilised carbon atom of the glycine (carboxyl group)removed before or after formation of the pyrrole rings 9 Evidence has beenadduced by Altman et a1.W in favour of the latter hypothesis, but theirarguments are open to the following criticisms :(u) Whilst a glycine decarboxylase is apparently unknown, and glycineresists oxidation in tissue slice experiments, NH2*CH,*l3CO,H is, in mice,extensively converted to respiratory CO, (see discussion, p. 245).(6) If decarboxylation takes place after pyrrole ring formation theliberated 14C0, could still be utilised in a subsequent condensation, in thesame way as Ca14C0, seems to be used.In fact, the apparent utilisationof Ca14C0,, the formation of respiratory CO, from glycine, and the non-incorporation of glycine carboxyl, would seem to be contradictory facts.The structural formulaof a compound, given in Chem. Abs. (1948, 42, 7757 b ) text, corresponds to an empiricalformula C,H,,O,N ; this does not agree with the quoted empirical formula, C,H,,O,NCa.The original gives analytical data in agreement with the latter empirical formula,but, again, none of the structural formulz proposed seem to agree with the empiricalformula.69 M. Errera and J. P. Greenstein, J .Nat. Cancer Inst., 1947, 8, 39.70 A. M. Kuzin and A. P. Guseva, Biochimia, 1948, 13, 27.The reaction seems worthy of further investigationBENTLEY : SMALL MOLECULES IN BIOSYNTHESIS. 257Owing to the relatively slow incorporation of isotope in the experimentswith implanted Ca14C0, pellets, the observed uptake into hzmin may havebeen the result of a general labelling of biosynthetic intermediates.Whilst there is no real evidence to show that decarboxylation takes placeafter the formation of the pyrrole ring, the suggestion of Altman et al. isprobably correct.(ii) What is the mechanism of porphyrin fornlation from pyrroles?In view of the equivalence of the ring nitrogen atoms, any theory mustaccount for porphyrin synthesis from a common pyrrole precursor, andfurther give an explanation of the formation of porphyrins of Types (I)and (111).In 1938, C. Rimington postulated that an enzyme system,present in bone marrow, was concerned with a dual synthesis of porphyrinsI11 and I (PI11 and PI) from a common precursor (A), and suggested thatthe events leading to one product were specifically accelerated, makingone isomer the main product : 7 l1 PI11 (Main)A ---_--+ PI (By-product)Dobriner et ~ 1 . ~ ~ pointed out that a combination of two different dipyrryl-methines (A and B) could give rise to porphyrins of Types (I), (11), and(111), thus :C;H:CH, M~A* = CH,*CH,*CO,H3/pAB_______371 Compf. rend. Tyav. Lab. Carlsberg, Sdr. China., 1938, 22, 454.72 K. Dobriner, W. H. Strain, and S. A.Localio, Proc. SOC. Exp. BioZ. Med., 1937,36, 752; K. Dobriner and C. P. Rhoads, Physiol. Reviews, 1940, 20, 416.REP.-VOL. XLV. 258 BIOCHEMISTRY.A scheme of this kind necessitates the introduction of two further methinebridges. These could conceivably be derived from a C, fragment; aninteresting possibility is that formate may be involved in porphyrin bio-synthesis. Turner 55 has visualised porphyrin synthesis in a similar way,and his suggestion is based on the aldehyde synthesis of dipyrrylmethinesin which the dipyrrylmethines are derived through a tripyrrylmethane.This ingenious hypothesis suggests that all porphyrins could be formedfrom three structural units, which themselves by known processes couldbe derived from a single pyrrole (111) :C02H*CH2-CH2*CH2*C02H CH3--CH2*CH2*C02H CH3-CH:CH2 I1 I1 + II It\/ \/ II II + \/(111.) (IV.) (V.1As an example of Turner's scheme the synthesis of uroporphyrins isUroporp h yrinIA .-> UroporphyrinI11UroporphyrinI1(Such units, Turner has suggested, could be derived from tryptophan.)represented below :a* = CH,*CH2*C0,H a = CH,*C02HThe formation of the bacterial pigment prodigiosin (a tripyrrylmethine)may acquire a fresh significance in this connection.A possibility whichdoes not appear to have been previously considered is a combination of aMe Et Me Et. .I 1I I I t! ! +-44c0, I -4H20J.Et CH, MeBtioporphyrkogen-IEt CH MeCH CH\- -4I \MeMe CH EtBtioporphyrin-BENTLEY : SMALL MOLECULES IN BIOSYNTHESIS.259dipyrrylmethine, such as A, with its mirror image. This would lead toporphyrins of Type (IV); like the Type (11) compounds, these are as yetunknown, and if such mechanisms take place it is necessary to supposethat the enzyme systems cannot handle these compounds.An alternative to mechanisms of this nature has been proposed byC. Rimington 73 on the basis of the decarboxylative condensation of sub-stituted 5-hydroxymethylpyrrole-2-carboxylic acids observed by Siedel andWinMer.74 When such compounds were heated alone or in solution,porphyrins were formed in yields of up to 40%.Whilst these schemes of biosynthesis are almost certainly too mechan-istic, and ignore almost completely the function of enzyme systems, theymay help to form a picture of porphyrin biosynthesis.The Life Span of the Human Red Blood Cell.-The study of haemoglobinsynthesis in red blood cells has provided a striking demonstration of acellular component which is not involved in the dynamic equilibrium ofthe body.As described earlier, blood samples were withdrawn from ahuman, for hzmin isolation, after the feeding of a massive amount of15NH2*CH2*C0,H.75 The plot of atom yo excess of 15N in the h=minagainst time gave a curve very different from that previously observed withany other cellular constituent (e.g., the tissue protein curves). After remain-ing constant for about 95 days as previously mentioned, the 15N concen-tration of the haemin began to decline rather abruptly along an S-shapedcurve.(1) If a cell component does not take part in the dynamic state, a newlysynthesised, labelled molecule will remain in the cell, until the cell dis-integrates.If indiscriminate cell destruction does not take place, theisotope concentration will reach a maximum value, which will then bemaintained a t a constant level for a period depending on the life span ofthe cell. If the isotope is not re-utilised a t the time of cell destruction, theisotope concentration of the cells will abruptly decline. This is seen to bethe case with the h*min obtained from red blood cells; inspection of thecurve (as well as a precise mathematical analysis) shows the life span of thered blood cell to be about 127 days.(2) The abrupt decline of the curve shows that the I5N is not re-utilisedfor hemoglobin synthesis (in contrast to the iron 76).It has been shownthat a large part of the porphyrin is excreted as ~tercobilin,'~ although notall of the stercobilin results from haemoglobin destruction. I n the firstfew days of the experiment (when labelled red cells were not being destroyed)there was an appreciable concentration of 15N in the stercobilin. A portionof the bile pigment therefore was derived from a source other than the73 Personal communication.74 W. Siedel and F. Winkler, Annalen, 1943, 554, 162; quoted in FIAT Review75 D. Shemin and D. Rittenberg, J . Biol. Chem., 1948, 153, 401.76 W. 0. Cruz, P. F. Hahn, and W. F. Bale, Amer. J.PhysioZ., 1941--1942,135, 595;7 7 I. M. London, R. West, D.Shemin, and D. Rittenberg, Fed. PTOC., 1948, 7, 169.This curve has a two-fold significance.of German Science, 1947, Biochemistry, Part 1, p. 132.P. F. Hahn, W. F. Bale, and W. M. Balfour, ibid., p. 600260 BIOCHEMISTRY.hzmoglobin of mature, circulating, red blood cells. It may be that thisincorporation takes place via a pyrrole precursor which may form eitherhzm or stercobilin.The Function of Acetic Acid.The 1945 Report discussed the nature of the primary oxidation productof pyruvic acid, which in some systems is a highly active C, intermediate.78Studies with isotopes have now revealed a high order of activity for aceticacid itself, which has been shown to be a precursor of glycogen, cholesterol,acetoacetic acid, fatty acids, the dicarboxylic amino-acids, protoporphyrin,uric acid, and the acetyl group formed in many acetylation reactions.Acetic acid as a sole carbon source supports almost all Escherichia andAerobacter species.79discusses acetate metabolism in considerabledetail, and only a few of the more recent observations can be reported here.The general metabolism of fatty acids will not be discussed.The Active Form of Acetic Acid.-It is still impossible to specify accur-ately the nature of the C, intermediate (or intermediates), but the increasedrealisation of the activity of acetate itself suggests that it may be a nearderivative of acetic acid.It seems increasingly unlikely that the inter-mediate is acetyl phosphate, and this compound retains some of its enig-matic character.Acetyl phosphate has been isolated from two new reac-tions brought about by Clostridium Eluyveri 8O (this organism forms hexoicacid from ethanol and acetic acid *l).Bloch's excellent reviewThese are :CH,*CHO + HPO,' + $0, --+ CH,*C02P03' + H,O,and also a phosphoroclastic decomposition of acetoacetate into acetylphosphate and acetate :CH,*CO*CH,*CO,- + HPO," --+ CH,*CO,PO,' + CH,*CO,-I n t'he early experiments of Lipmann and his colleagues, acetyl phosphatewas shown to transfer its phosphate group to glucose in the presence ofbacterial enzymes, and a similar transfer has now been observed with apigeon-liver extract .@ It was never possible to demonstrate an acetylatingfunction for acetyl phosphate, although it was observed that acetyl phos-phate would acetylate aniline and ammonia in non-enzymic reactions.83, 84A reversal of the initial phosphoroclastic decomposition of pyruvate wasdemonstrated in E.coli preparations by isotope technique^,^^ but it nowappears that this transfer of " acetyl" was, partly at least, not a true78 P. Dickens, Ann. Reports, 1945, 42, 197.7s W. E. Clapper and C. F. Poe, J. Bact., 1947, 53, 363.81 H. A. Barker, M. D. Kamen, and B. T. Bornstein, Proc. Nut. Acad. Sci., 1945,82 N. 0. Kaplan and F. Lipmann, Ped. Proc., 1948, 7, 163.84 R. Bentley, J . Arner. Chem. SOC., 1948, 70, 2183.86 M. F. Utter, F. Lipmann, and C. H. Werkman, J. BioZ. Chem., 1945,158, 521.E. R. Stadtman and H. A. Barker, J . BioZ. Chem., 1948,174, 1039.31, 373.F. Lipmann, J.BioZ. Chem., 1945, 160, 184BENTLEP SMALL MOLECULES IN BIOSYNTHESIS. 26 1reversal of the initial reaction. In a further examination of the role ofacetyl phosphate, 13CH,*C0,H, CH,*13C02P03H,, and H*14C02H were pre-pared and added to normal pyruvate in the E. coli system.86 After partialfermentation of the pyruvate the reaction products were lactate and CO,[indicating that some of the pyruvate took part in a dismutation reaction :2CH,*CO*CO,H -+ CH,*CH(OH)*CO,H + CH,*CO,H + CO,]. The resi-dual pyruvate was decomposed with yeast carboxylase, so that the carbonatoms could be identified. The carboxyl carbon was found to have a high14C content ( i e . , derived from formate), but the a- and p-carbon atoms didnot contain any l3C. In addition NaH1*CO, was not significantly fixedunder these conditions, so the formate was not iirst converted into CO,.These results indicated that formate was fixed in pyruvic acid withouteither acetate or acetyl phosphate acting as essential intermediates.Itwas suggested that the synthetic acetyl phosphate used in these experi-ments may not have been identical with the biological acetyl phosphate.The dismutation of pyruvate referred to in the preceding paragraphhas been separately studied, and by the use of NaH13C03 and cell free extractsof Staphylococcus aureus, it was shown that the reaction was reversible;after the incubation, 13C was found in the carboxyl group of p y r ~ v a t e . ~ ~In further experiments, Lipmann has shown that, with E. coli extracts,an '' acetyl " transfer took place when acetate was incubated in the presenceof added ATP, although acetyl phosphate was quite inactive under thescconditions.88 In the absence of an acetate acceptor, large amounts of an" acetyl-phosphate-like I ' compound accumulated.This compound differedfrom acetyl phosphate in its resistance to a specific muscle acetyl phos-phatase, but on standing in acid solutions, even a t room temperature, itbecame indistinguishable from acetyl phosphate ; it was not diacetyl phos-phate. I n dialysed E. coli suspensions, the compound (which was free fromATP and contained only traces of other organic phosphates) reacted almostquantitatively with excess of formate to yield pyruvate. Synthetic acetylphosphate reacted only in the presence of ADP, the former presumably asa phosphate donor.In a study of the hydrolysis of acetyl phosphate with the use of H2180it has been shown that acetyl phosphate splits in alkaline solution withrupture of the C-0 bond (VI), and in acid solution with rupture of theP-0 bond (VII).89I:W.) (VII.)86 H.Strecker, L. 0. Krampitz, and H. G. Wood, Fed. Proc., 1948, 7, 194.87 T. Wikh, D. Watt, A. G. C. White, and C. H. Werkman, Arch. Biochem., 1947,14, 478.N. 0. Kaplan and F. Lipmann, J:BioZ. Chem., 1948,178, 459.as R. Bentley, Cold Spring Harbor Symp., 1948, 13, 15; J . Amer. Chenz. SOC.,in the press262 BIOCHEMISTRY .The mechanism of acetylation (e.g., of sulphanilamide) in pigeon-liverextracts has been further elucidated by Lipmann’s work; the reaction wasnotably increased by the addition of acetate, and under anaerobic conditionsrequired ATP.It was found that a thermostable component of boiled-liverpreparations could be used to reactivate the enzyme system.g* This propertywas traced to the presence, in such extracts, of a coenzyme containing about10% of pantothenic acid. This coenzyme, named Coenzyme A, was alsorequired by the similar acetylation system for choline in brain.g1 Co-enzyme A is a fairly general constituent of living organisms, the highestassays having been recorded in liver, Clostridium butylicum, and Proteusrnorganii. The combined pantothenic acid of the Coenzyme A is not avail-able to L. casei until after hydrolysis; the acid is apparently bound inthe coenzyme by two linkages, one of which is to phosphate.92The role of pantothenic acid in the metabolism of pyruvate by Proteusmorgunii has also been studied.The stimulation of respiration producedby addition of pantothenic acid to pantothenate-deficient cells could notbe accounted for by oxidation of the acetate. When pantothenic acid wasabsent, acetylmethylcarbinol accumulated, suggesting that a pantothenicacid containing coenzyme was concerned with the utilisation of acetyl-methylcarbinol or a related compound.The in vitro synthesis of acetylcholine, mentioned earlier, has beenfurther studied in brain extracts. The acetylation of choline proceedsaerobically in the presence of glucose, lactate, or pyruvate, or anaerobicallytogether with added ATP.Synthesis is in no case stimulated by additionof acetate, thus leaving doubt as to the source of the acetyl group. Anumber of compounds have been suggested as this source.94 A completelysoluble enzyme system has been described which in addition to choline andATP requires the thermostable coenzyme and a substance providing asource of ‘‘ active acetate.’, This substance can be citrate, cis-aconitate,or acetoacetate, and it was suggested that the active groups were derivedas shown :Acetoacetate + H,O + 2 acetateCitrate + oxaloacetate + acetate.I n continuing his studies on the biosynthesis of cholesterol (about halfthe carbon atoms of which are derived from acetate) and fatty acids, Blochhas emphasised that the C, unit obtained from pyruvate is not the same asthat derived from acetic acid, a fact first suggested by their differentbehaviour in acetylation reactions.96 Fatty acid formation can hardly be9 1 F. Lipmann, N.0. Kaplan, G. D. Novelli, L. C. Tuttle, and B. M. Guirard, ibid.,92 N. 0. Kaplan and F. Lipmann, ibid., 1948, 174, 37 ; D. M. Hegsted and F. Lip-93 0. E. McElroy and A. Dorfman, ibid., 1948, 173, 805.94 D. Nachmansohn and H. M. John, ibid., 1945, 158, 157.95 M. A. Lipton and E. S. G. Barron, ibid., 1946, 166, 367.s6 K. Bloch and D. Rittenberg, ibid., 1945, 159, 45.F. Liprnann, J. Biol. Chem., 1945, 160, 173.1947, 167, 871.mann, ibid., p. 89BENTLEY : SMALL MOLHCULES IN BIOSYNTHESIS. 203demonstrated in surviving liver tissue with acetic acid as the only substrate,although under these conditions labelled acetate is rapidly incorporatedinto cholesterol showing that a biosynthetically active form of acetate isindeed prod~ced.~' On the addition of pyruvate and to a lesser extent ofoxaloacetate a marked incorporation of acetate into fatty acids takes place;other dicarboxylic acids are ineffective. The interpretation of these resultsis not yet clear.The conversion of acetic and butyric acids into liver glycogen has beenstudied in rats.98 When CH3*l3CO2H, CH,*CH2-CH,*13C0,H, andCH3*13CH,*CH,*C0,H were fed, the isotope distribution in glycogen wassimilar to that observed when CO, was incorporated (i.e., in the 3 and 4positions of the glucose units).However, when 13CH3*C0,H, 13CH3-13C02H,and CH3*CH,*13CH,-C0,H were examined, fixation took place in all thefractions obtained on degradation of the glycogen, showing that someincorporation of these acids into glycogen took place by pathways otherthan those involving CO, fixation.The observed isotope distributions wereconsistent with the following conclusions.(i) Formation of C, fragments from acetate and butyrate via the tri-carboxylic acid cycle, and synthesis of glucose units by condensation oftwo such fragments.(ii) p-Oxidation of butyrate to 2 molecules of acetate, but not w-oxid-ation with the production of succinate.I n early experiments on the oxidation of CD3*C0,H by yeast, succinatewas obtained containing more excess D than the citrate; g9 Lynen pointedout that such a distribution was consistent with the assumption that themetabolism took place via.a tricarboxylic acid cycle.100 In new experiments,CH3*13C0,H was metabolised by yeast ; a high 13C concentration was foundin cell lipins (the fatty acids contained more 13C than the unsaponifiablematerial, and the saturated fatty acids 50% more isotope than the un-saturated acids).lOl Isotope was incorporated into citrate as shown in theannexed table. On the other hand, during the oxidation of normal acetateexcess. yo.Citrato total ........................ 1.94 35Primary carboxyl .................. 4-42 80Respiratory CO, ..................... 3.1 1 56Acetate cmboxyl ................... 5.54 100Tertiary carboxyl .................. 3-16 57Non-carboxyl C .....................0.00 0in presence of NaK13C03 no l3C was found in any product isolated. Thelast column gives the values calculated on the basis of 100 atom yo of 13C9 7 K. Blocli and W. Kramer, J . Biol. Chem., 1948, 173, 811.9 8 N. Lifson, V. Lorber, W. Sakami, and H. G. Wood, &id., 1948, 176, 1263.99 R. Sonderhoff and H. Thomas, A?znaEsn, 1937, 530, 195.loo F. Lynen, ibid., 1943, 554, 40.lol S. Weinhouse and R. H. Millington, J . Amer. Chern. SOC., 1947, 69, 3089264 BIOCHEMISTRY.in the acetate carboxyl ; these figures (in parentheses) are consistent withthe following scheme :bH3*602H (100) + (57) H0,6*hH2*60*60,H (57)IJ.(57) H0,&6H2*~(OH)*6H2*602H (100)J, 6C02H(57)(0) HOz6*&H2*bH,*602H (100) + 60, (57) + 60, (57)Any C, acid formed in this way by the cycle could have only 50% of acetate13C in the carboxyl groups.Since the value actually observed was 57%,the authors suggested that there is a supplementary mechanism for theformation of C, acids independent of the tricarboxylic acid cycle :BCH,*CO,H + HO,C*CH,*CH,*CO,HThese results therefore were in good agreement with the distribution to beexpected if the tricarboxylic acid cycle was involved; it seemed likely thatan unsymmetrical C, acid, rather than citrate, was the direct participantin the cycle.In another study of acetate assimilation by yeast (Saccharomyces cere-vesice), the following fixations of isotope from CH3J3C0,H (4.33 atom yoexcess of 13C) were observed lo2 (cf. below). The lactic acid derived fromAtom %excess of 13C.Residual acetate .............................. 0.08Fat ................................................1-49Fatty acids ....................................... 1.14Lactic acid from gIucose ..................... 0.09Lactate CO,H ................................. 0.30,, CH, .................................... 0.02., CH*OH .............................. 0.00glucose had 13C only in the carboxyl group, as would be expected if theintact acetate molecule was metabolised, and it was shown that the incor-poration was not due to a prior oxidation to CO,. Incorporation of acetateinto fat was also a result of direct utilisation of the C, molecule, withoutprior conversion into carbohydrate. The optimum conditions for fatsynthesis in yeast have been studied by the same authors.lo3Another study with yeast has been that of the formation of acetyl-meth ylcarbinol ; 13CH3J3CH0 was used, and the conclusion made thatacetylmethylcarbinol was formed by condensation of pyruvic acid anda~eta~ldehyde.104lo2 A.G . C. White and C. H. Werkman, Arch. Biochena., 1947, 13, 27.lo3 Idem, ibid., 1948, 17, 475.lo4 N. H. Gross and C. H. Werkmrtn, ;bid., 1947, 15, 126BENTLEY : SMALL MOLECULES IN BIOSYNTHESIS. 265The Utilisation of Carbon Dioxide in Biosynthesis.This subject was first reviewed in the Annual Reports for 1941.1°5Since then, other fixation reactions of carbon dioxide have been discovered ;these have been reviewed recently by and some of the enzymicmechanisms involved have been reviewed by 8.Ochoa.lO6 In this Report,discoveries since 1946 (the date of Wood’s review) will be discussed.C, and C, Addition by the Phosphoroclastic Reaction.-The work ofJ. Wilson, L. 0. Krampitz, and C. H. Werkman (cf. Wood, ref. 5, p. 205)has now been published in detail.lo7 This constitutes the first demonstra-tion of C, and C, addition where CO, per se is the C, compound fixed.With Clostridium butylicum (in contrast to E. coli) formic acid is not anintermediate in the phosphoroclastic reaction :CH,*CO*CO,H + H,PO, += CH,*CO,PO,H, + CO, + H,When NaH13C03 and a buffered enzyme preparation were used, 13C wasfixed only in the pyruvate carboxyl group, but in the presence of H*13C0,Hthere was no exchange of isotope into the pyruvate.With CH,*13C0,Hthere was a very slight exchange, which was significantly greater in thepresence of adenylic acid and acetyl phosphate, or on addition of ATP.C, and C, Addition by Oxaloacetate-p-carboxy1ase.-The original Wood-Werkman reaction was first demonstrated in pigeoii-liver extracts byM. F. Utter and H. G. Wood; the reaction took place only in the presenceof ATP : lo813C0, + CH,*CO*CO,H H0,13CCH,-CO*C0,HThe effects of TPN and ATP on pigeon-liver oxaloacetic carboxylase havenow been examined.109 ATP causes a small inhibition of the decarboxyl-ation of oxaloacetic acid, whilst TPN causes a marked stimulation. Whenthe exchange between l*CO, and the fharboxyl group was similarly studied,the reaction was found to be influenced in the opposite direction : the exchangewas stimulated by ATP, but not by TPN.The pigeon-liver oxaloaceticcarboxylase has recently been described by Ochoa et aZ.l10 In the presenceof Mn-’ +, the enzyme decarboxylates malic acid, and functions in the absenceof inorganic phosphate and ATP. It is TPN specific.H02C*CH,*CH(OH)*C02H + TPN,,. + CH,*CO*CO,H +- CO, + TPN,,d.The same enzyme catalyses the decomposition of oxaloacetic acid. Bycoupling with the glucose-6 -phosphate dehydrogenase system, fixation ofcarbon dioxide takes place :Pyruvate + CO, + glucose-6 phosphate + malate + 6-phosphogluconateIo5 M. Stephenson and H. A. Krebs, Ann. Reports, 1941, 38, 257.lo6 Currents in Biochemical Research, 1946, 165.Io7 Biochem. J., 1948, 42, 598.log B.Vennesland, E. A. Evans, and I(. I. Altman, ibid., 1947, 171, 675.1x0 A. H. Mehler, A. Kornberg, S. Grisolia, and S. Ochos, ibid., 1948, 174, 961;108 J . Biol. Chem., 1946, 164, 455.S. Ochoa, A. H. Mehler, and A. Kornberg, ibid., p. 979266 BIOCHEMISTRY.The relation of these reactions to the previously described carbon dioxidefixation in oxaloacetate, requiring ATP, is a matter for conjecture.Parsley root contains an oxaloacetic carboxylase, and this reaction hasalso been shown to be reversible by the fixation of 14C02 into oxaloacetateduring the decarboxylation.111 The preparation also contained a malkdehydrogenase, and, when pyruvate and malate were incubated with l4COZ,14C was fixed in malate. These results suggest that (analogously to animalsand bacteria) the plant dicarboxylic acids are formed via an initial Wood-Werkman reaction.Some properties of this plant oxaloacetic carboxylaseand its quantitative assay have been described recently. lllaC, and C, Addition.-An important new type of heterotrophic assimil-ation of carbon dioxide has now been described which involves C, and C,addition.l12 A cell-free enzyme preparation was obtained from E. coEiwhich decarboxylated a-ketoglutarate to . succinate and carbon dioxide ;malonate was present to inhibit the oxidation of the succinate. Thesystem reversibly fixed 13C02 in the carboxyl group adjacent to the carbonylcarbon atom of ketoglutarate; fixation was increased by the addition ofATP, and it was suggested that a phosphorylated form of succinate mayhave been involved. This reversible oxidative decarboxylation is thereforeas follows :HO,C*CH,*CH,*CO*CO,H + 0 =+ HO,C*CH,*CH,*CO,H + CO,This observation finally completes the evidence for the complete reversalof the Krebs' tricarboxylic acid cycle.Since a-ketoglutarate could replacecarbon dioxide to a greater extent than other C, acids, the authors suggestedthat normally the C, and C, addition may be of greater importance thanthe other known fixation reactions.C5 and C, Addition by Oxalosuccinic Carboxy1ase.-Since the publicationof Wood's review, a detailed account has appeared of the work of Ochoaand his colleagues with the oxalosuccinic carboxylase system. 113 Resultssimilar to those of Ochoa have been obtained with isotopes.ll* Incor-poration of 14C into the p-carboxyl group of isocitric acid took place whena-ketoglutarate and isocitrate were incubated with NaH14C03 in the presenceof an oxalosuccinic carboxylase preparation from pigeon liver,MU+" HO,C*CH,*CH*CH( OH)*CO,H + TPN,,. HO,C*CH,*CH,*CO*CO,HI%0,Hisocitrate.+14C0, + TPNmd.a-Ketoglutarate.111 M.C. Gollub and B. Vennesland, J. Biol. Chem., 1947, 169, 233.Illa B. Vennesland, M. C. Gollub, and J. F. Speck, ibid., 1949, 178, 301.112 S. J. Ajl and C. H. Werkman, Proc. Nut. Acad. Sci., 1948, 34, 491.113 S. Ochoa, J . BioE. Chern., 1948, 174, 115, 133; S. Ochoa and E. Weisz-Tahori,114 S. Grisolia and B. Vennesland, ibid., 1947, 170, 461.ibid., p. 123MARTIN : PARTITION CHROMATOGRAPHY.267A similar reaction has been studied in connection with tricarboxylic acidsynthesis by carbon dioxide fixation in parsley root preparations.l16Carbon Dioxide Utilisation by the Animal.-Despite the relatively largeoutput of carbon dioxide by the intact animal, it has been possible to studycarbon dioxide utilisation; A. M. Delluva and D. W. Wilson gave hourlyintraperitoneal injections of NaH13C0, (18 hours) to a rat.115. 13C wasfound in a carboxyl group of aspartate and the a-carboxyl group of glut-amate. These compounds were presumably derived from amination ofthe primary fixation products, oxaloacetate and a-ketoglutarate. (In astudy of the in vitro turnover of dicarboxylic amino-acids in liver sliceproteins, 14C from Na214C0, was similarly incorporated entirely into theseacids via a-ketoglutarate and oxaloacetate.) 13C was also found in theamidino-carbon atom of arginine, again supporting the participation ofarginine in Krebs' urea cycle.Armstrong and his co-workers have studied the distribution of I4Cfollowing incorporation from inorganic carbonates (Na, Bay Ca).l17 Avery small fraction of 14C was incorporated into the fatty acids, and to alesser extent into the unsaturated fatty acids.The 14C content of thecarboxyl group of the saturated and total fatty acids was twice as great asthe average of all the carbon atoms in the respective fatty acids. Absorp-tion of 14C activity from intraperitoneally implanted Ca14C03 pellets wasslower, but gave greater incorporation than the intraperitoneal injection ofNa,14C0,.14C was found in many compounds including hzemin, fatty acids,and glycerol.In other experiments, the rate of l4C0, excretion following intraperi-toneal administration of isotopic bicarbonate (and acetate) has beenfollowed.lls The excretion reached a maximum within 10 minutes ofinjection, and thereafter the specific activity of respiratory CO, decreasedexponentially for about an hour; the rate of decrease then became con-siderably slower.R. B.5. PARTITION CIIROMATOGRAPHY.Partition chromatography has now a substantial literature, which isThis technique has already been ,applied to the separ-Review articles on chromatography, includingR. L. M. Synge andrapidly increasing.ation of some 200 substances.partition chromatography, have been published; 1,A.J. P. Martin have written on partition chromatography, and M. HaisJ . Biol. Chem., 1946, 186, 739.116 B. Vennesland, J. Ceithaml, and M. C. Gollub, i b i d . , 1947, 171, 445 ; J. Ceithamll17 J. D. Schubert and W. D. Armstrong, Science, 1948, 108, 286; W. D. Arm-118 R. G. Gould, I. M. Rosenberg, M. Sinex, and A. B. Hastings, ibid., p. 156.and B. Vennesland, ibid., 1949, 178, 133.strong, J. Schubert, and A. Lindenbaum, Fed. Proc., 1948, 7, 143.A. J. P. Martin, Endeavour, 1947, 6, 21.T. I. Williams, Research, 1948,1,400.Ann. N . Y . Acad. Sci., 1948, 49, 249.Analyst, 1946, 71, 256.Chem. Listy, 1948, 42, 126268 BIOCHEMISTRY.and R. Consden on partition chromatography on paper (for which thename “ papyrography ” has been suggested; 7 cf.“ papergrams ” s).Chromatography of amino-acids and peptides has been discussed by Martinand Synge The Biochemical Societyhas held a symposium on partition chromatography. l1and by E. Brand and J, T. Edsall.loIllheoretical.Principles of Chrornatography.-Theories of chromatography make basicassumptions about (a) the equilibrium concentrations of solutes betweenthe moving and the stationary parts of the chromatogram (Le., the a d s o ption isotherm or partition coefficient), ( b ) the rate of establishment ofequilibrium, ( c ) the diffusion of the solute between moving and stationaryparts, and (d) the diffusion of solute along the length of the column. Theyare not necessarily concerned with mechanisms responsible for the relationsassumed.Thus, in general, the theory of adsorption and of partitionchromatograms is the same.No theory has yet attempted to take account of all known importantfactors. For instance, J. N. Wilson,12 D. De Vault,l3 J. Weiss,14 andE. Glueckauf l5 assumed instantaneous equilibrium and no diffusion, butallowed for a non-linear adsorption isotherm. These theories have beenapplied chiefly to adsorption chromatograms where the adsorption isothermsare frequently strongly curved and establishment of equilibrium is rapid.Martin and Synge l6 assumed a linear isotherm (constant partition co-efficient), introduced the “ theoretical plate ” concept from distillationtheory to allow for diffusion from moving to stationary parts, and neglectedother diffusion.S. W. Mayer and E. R. Tompkins l 7 developed this theoryto permit easy calculation of the concentration in the effluent. The theoryhas been applied to partition and ion-exchange chromatograms where thepartition coefficient is practically constant. A. A. Levi l 8 applied DeVault’s theory to a buffer-loaded partition column where so much acidhad been used that appreciable changes of pH resulted and the partitioncoefficient was no longer constant. Caution must be used in drawing con-clusions from this theory for it might be inferred that a long column possessesno advantage over a short, wide one of the same weight,ls a deduction renderedpossible only because diffusion of all kinds has been neglected.H. C.Thomas l9 and L. G. Sillen 2O have included a slow adsorption in the theory,C. E. Dent, Biochem. J., 1948,43,169. Nature, 1948, 162, 359.Advances in Protein Chemistry, 1945, 2, 1.* R. M. Tamarelli and K. Florcy, Science, 1948, 107, 630.lo Ann. Rev. Biochenz., 1947, 16, 223.l1 Proceedings of Symposium on Partition Chromatography, Biochemical Society,l2 J . Amer. Chem. SOC., 1940, 62, 1583.l4 J., 1943, 297.l6 Biochem. J . , 1941, 35, 1358.Biochem. J., 1948, 43, 257.*O Arkiv Kemi, Min., Geol., 1946, 22, A , No. 15.1949.l3 Ibid., 1943, 65, 532.l5 J., 1947, 1302, 1308, 1321.l7 J . Amer. Chem. SOC., 1947, 69, 2866.lQ Ann. N . Y . Acad. Sci., 1948, 49, 161MARTIN : PARTITION CHROMATOGRAPHY. 269as has E. Glueckauf,21 who in a preliminary paper 22 has written an equationwith terms for most of the factors mentioned above.There would appearto be little hope of any solution of this equation simple enough to beuseful.A. Tiselius 23 has given a simple theory of displacement development,and he and S. Claesson 24 develop a general theory of frontal analysis, instan-taneous equilibrium being assumed in each case. Martin l1 has given anapproximate theory of displacement development on buffered or acid- orbase-loaded columns, using the theoretical plate method and showing theclose analogy with a distillation column operating a t total reflux. It canbe inferred from the theory that these displacement columns have not onlya high capacity, but also a high resolving power.Nothing has been pub-lished concerning the application of these columns, but wide use both inindustry and in the laboratory should be possible.Factors influencing the Partition Coeiiicient.-Martin l1 has consideredthe factors upon which partition coefficients depend and suggests thefollowing rules :(1) Let aA be the partition coefficient of substance A and aB that ofsubstance B between a given pair of phases. Then, if A and B differonly in that B has a given extra group, e.g., OH, CH,, glycyl, etc.,the ratio a A / @ B depends only on the extra group and on the pair ofphases.(2) As a corollary, the ratio aA/aB for substances A and B is unchangedby forming derivatives AX and BX, i.e., aA/aB = aAx/aBx = aAy/aBY = . . .etc. Thus the ease of separating two substances in a given sohenti systemwill be unchanged whatever derivative be employed, provided that such aderivative be chosen that a does not have an inconveniently high or lowvalue.(3) Isomers containing the same functional groups should have identicalpartition coefficients.Deviations from these rules will be largely the result of steric factors.Hence it is probable that adsorption on a solid will, in general, distinguishbetter between isomers than does partition between liquids.Varieties of Partition Chromstomams.-The partition chromatogram usedby Martin and Synge l6 for the separation of acetylated amino-acids con-sisted of precipitated silica loaded with water.Various modifications havesince been made to extend its use to other substances.Heilbron and hisco-workers 2 5 9 26 added a basic substance, e.g., barium carbonate, to thesilica and thereby were able to retain penicillin on the columns. A frontalanalysis type of chromatogram thereby resulted, which gave only partial81 J., 1947, 1315.*2 Discussion on New Techniques, Chemical Society, Nov. 26th, 1948.24 Arkiv Kerni, &lira., Gwl., 1946, 23, A, No. 1.26 R. C. Elliott, I. A%. Heilbron, A. H. Cook, and J. R. Catch, B.P. 558,320.26 J. R. Catch, A. H. Cook, and I. M. Heilbron, Nature, 1942, 150, 633.See Advances in Protein Chemistry, 1947, 3, 67270 BIOCHEMISTRY.separation (see Tiselius 23).* Levi 27 used a strong phosphate buffer insteadof barium carbonate, obtaining the usual type of elution development, andwas able to effect the first clear separation of different penicillins.The useof buffers on the chromatogram for the separation of acidic and basic sub-stances is now well established, and various applications of it will bementioned below. A. H. Gordon, A. J. P. Martin, and R. L. M. Synge28used two non-aqueous phases on precipitated silica in an attempt to purifygramicidin.Instead of silica, R. Consden, A. H. Gordon, and A. J. P. Martin 29 usedfilter-paper for amino-acid separations, and also introduced the use ofdevelopment in two dimensions. R. R. Goodall and A. A. Levi30 usedpaper loaded with buffer for penicillin separations. Synge 31 used starchcolumns for amino-acids and peptides. Kieselguhr has been proposed,25among other substances, as an alternative to precipitated silica.It hasbeen used with buffers for penicillin and with sulphuric acid for fatty-acidseparation^.^^ Martin l1 has suggested that it could replace precipitatedsilica with advantage in many cases.The partition chromatogram works conveniently within a range ofpartition coefficients of 1 : 1 to 1 : 100 in favour of the stationary phase.A wide extension of its use should be possible, therefore, if means could befound for making the less polar phase the stationary one. To this end,R. J. Boscott 33 has suggested the use of acetylcellulose and J. Boldingh 34has used paper loaded with vulcanised rubber latex, and methanol as solvent,for the separation of esters of higher fatty acids. Martin,35 by treatingkieselguhr with dimethyldichlorosilane, has given it a surface not readilywettable by polar solvents; thus treated, it will satisfactorily hold the lesspolar of a given phase pair.G.Haugaard and T. D. Kroner 36 have used simultaneous separation ina horizontal direction by ionophoresis and in a vertical direction by partitionchromatography. The paper is loaded with buffer and vertical electrodes areattached near the edges of the paper. The whole is then developed as achromatogram in the usual way.Since then a variety of non-aqueous systems has been used.27 A. A. Levi, S. G. Terjessen, and I.C.I., B.P. 569,844; see also ref. 18.28 Biochem. J . , 1943, 37, 86.30 Nature, 1946, 158, 675. 31 Biochem. J . , 1944, 38, 285.32 M. H. Petersen and M.J. Johnson, J . Biol. Chem., 1948, 174, 775.33 Nature, 1947, 159, 342. 34 Experientia, 1948, 4, 270.35 To be published. 36 J . Arner. Chem. SOC., 1948, 70, 2135.* In this type of chromatogram only the fastest-running material can be obtainedpure, for some of the substance of each zone extends back to the top of the column.Thus, if the substances A, B, C, and D are run on a frontal-analysis column, zone 1contains A, zone 2 contains A + B, zone 3 contains A + B + C, and zone 4 containsA + B + C + D, the proportions of A, B, C, and D in zone 4 being those which wouldbe found in the stationary phase if a small volume of the latter were shaken with alarge volume of the original solution in the mobile phase. If this type of column isdeveloped with am acid, E, slower moving than D, a displwement chromatogram isestablished in which, finally, the zones consist of A, B, C, D, and E more or less sharplyseparated from each other.Ibid., 1944, 38, 224MARTIN : PARTITION CHROMATOGRAPHY.271Absorption.-It is not possible, in all cases, to eliminate adsorption onthe carrier material, e.g., silica, starch, or cellulose. I n the original columnsof precipitated silica,16 a small percentage of alcohol was necessary toreduce absorption, and later various empirical methods of preparation 37were advocated to obtain non-absorptive silica. The problem of its pre-paration has not yet been completely solved. Kieselguhr may well proveto be less adsorptive. When buffers are used on the column, adsorptionseems to cause less trouble.38When cellulose or starch is used as support, it is more difficult to decidewhat part is played by adsorption.True adsorption certainly occurs.S. Moore and W. H. Stein 39 have demonstrated adsorption of certain amino-acids on starch, which accounts, to some extent a t least, for the differencesin the rates as expected from partition coefficients and as measured on thecolumns.Lin-stead and his colleagues 40 question whether the governing factor is partitionin this case, because “ activation ” of the paper with nitric acid is desirableand solvents miscible with water can be used.R. E. Horne and A. J. Pollard41 have used paper for streptomycinseparations ; 3 % aqueous ammonium chloride is used as solvent.It seemsimprobable that partition plays any part here. Perhaps the action is asfollows. The cellulose is initially saturated with water which graduallydilutes to pure water the advancing front of solvent. The streptomycinis absorbed by paper from water and eluted by ammonium chloride solution.Hence it is found near the front in a region of rising ammonium chlorideconcentration.There are, however, cases where it is difficult to decide whether adsorp-tion or partition is the proper name for what occurs. Paper chromatogramsmay be run with solvents miscible with water ; 299 36 these solvents, however,are usually readily salted out. It is reasonable to suppose, therefore, thatthe solvent within the cellulose is richer in water than the mobile phase,the organic material being ‘‘ salted out ” to some extent by the cellulose.Apartition coefficient differing from unity is therefore to be expected betweenthe mobile solvent and the solvent within the cellulose. One may, how-ever, regard the phenomenon as one of absorption by the solvent-swollencellulose.Partition Chromatography of Large Molecules.-The limit of size of moleculethat can be handled on paper, starch, or precipitated silica is not welldefined. It is not to be expected that very large molecules can penetrate3 7 A. H. Gordon, A. J. P. Martin, and R. L. M. Synge, Biochem. J., 1944, 38, 65;F. A. Isherwood, ibid., 1946, 40, 688; G. R. Tristram, ibid., p. 721 ; R. Harriss andA. N. Wick, Ind. Eng. Chem. Anal., 1946, 18, 276.Paper chromatograms have been used for inorganic separations.38 V.Moyle, E. Baldwin, and R. Scarisbrick, Biochem. J., 1948, 43, 308.39 Ann. N . Y . Acad. Sci., 1948, 49, 265.40 T. V. Arden, F. H. Burstall, G. R. Davies, J. A. Lewis, and R. P. Linstead,4 1 J . Bact., 1948, 55, 231,Nature, 1948, 162, 691272 BIOCHEMTSTRY.those supporting substances, although peptides containing several amino-acid residues behave satisfactorily. Adsorption may play an increasingpart as molecular size increases, and the chromatograms may act simul-taneously by partition for small molecules and by adsorption for large.Kieselguhr, since it holds the stationary phase essentially in droplet form,should offer no limitation to molecular size. It may well be difficult tofind two phases which are immiscible but yet are both solvents for a givenvery large molecule.Apparatus.The apparatus normally used for adsorption chromatography can beused also for partition columns.Apparatus for collecting numerous fractionsof the effluent has been described by Moore and Stein ; 399 42 a photo-cell andcounter mechanism rotates a test-tube rack (80 tubes) after a predeter-mined number of drops. S. S. Randall and A. J. P. Nartin 43 have useda syphon with a long arm delivering to a stationary rack; the weight ofliquid operates an escapement which permits the syphon to rotate. Toobserve the passage of zones of ionic material, they record the conductivityof the outflowing solution.I s h e r ~ o o d , ~ ~ unable to use an indicator on his silica column since itwas loaded with sulphuric acid, allowed the effluent to run down a capillarytogether with an indicator solution.Equilibration was sufficiently rapidfor the presence of acid in the effluent to be detected almost immediately.B. Drake 44 has described an automatic tester, drops of effluent falling ona drum of suitably prepared paper a t regular intervals.The apparatus used by Consden, Gordon, and Martin29 for paperchromatography has been modified by several worker^.^, 45 Methods ofmaking glass troughs have been published ; 46 however, troughs of stainlesssteel are perhaps the most satisfactory. 45 glass,29* 47and " Perspex " 48 have all been employed. Unless temperatures are verysteady, for long runs in large vessels, a penthouse roof is desirable so thatcondensed solvents shall not drip back on to the chromatograms.Williams and Kirby45 allow the solvents to rise by capillarity up asuspended strip or cylinder of paper standing in a circular jar.This methodrequires a minimum of apparatus, but development is slower, and solventtravel is limited to the length of the paper, a disadvantage for slow spots.An advantage for fast spots is that they cannot run off, and the chromato-Boxes of42 J . Biol. Chern., 1948, 176, 337.43 Biochem. J., Proc. 1949. 44 Nature, 1947, 160, 602.45 R. D. Hotchkiss, J . Biol. Chem., 1948, 175, 315; M. Macheboeuf and J. Blass,Ann. Inst. Pasteur, 1947, 73, 1053; W. A. Winsten, Science, 1948, 107, 605; R. J.Williams and H. Kirby, ibid., p.481 ; F. C. Steward, W. Stepka, and J. P. Thompson,ibid., p. 451; R. R. Goodall and A. A. Levi, Anqlyst, 1947, 72, 277; P. B. Baker,F. Dobson, and A. J. Martin, Nature, in the press.4 6 W. H. Longenecker, Science, 1948, 107, 2 3 ; H. F. Atkinson, Natwe, 1948, 182,858.4 7 Hotchkiss, loc. cit., ref. 45; Winsten, ibid; Williams and Kirby, ibid.4 8 Baker, Dobson, and Martin, Nature, in the pressMARTIN PARTITION CHROMATOGRAPHY. 273gram can be left unattended for long periods. The resolution of the spotsfor the same development seems unaffected.The use of very volatile solvents and of paper loaded with strong buffersolutions presents special problems in maintaining the atmosphere exactlysaturated with respect to both phases. Goodall and Levi45 used paperloaded with 30% potassium phosphate solution and diethyl ether as solventsfor penicillin separations.They operated in a chamber with minimum freespace a t 0"; a wet cloth lined an inner wall to maintain a water-saturatedatmosphere. This procedure may be criticised on the grounds that noequilibrium can be set up between atmosphere and strip. Baker, Dobson,and Martin45 pumped a mixture of &he two phases or of organic phaseand a salt solution of the required vapour pressure continuously over clothon the inner walls of the tank. The strips came rapidly to equilibriumand reproducible chromatograms were readily obtained. They believethis method to be of general utility for volatile solvents and for bufferedpaper.Consden, Gordon, and Martin 49 and C.E. Dent 50 have described piecesof apparatus for eluting peptides spots from chromatograms and also fortheir subsequent hydrolysis and deamination.D. M. P. Phillips 51 has devised a graduated rubber strip for the rapidestimation of R, values. (The R, value is the ratio of the movement of thespot to the movement of the solvent front.29)Consden, Gordon, and Martin49 have described a method for removingsalts from amino-acid solutions before chromatography.Methods for detecting Substances on Paper Chromatograms, and SpecialMet hods of Identification.Before use can be made of paper chromatograms, a method for detectinga few micrograms or less of the substances to be investigated must beavailable. A general reagent, revealing a large number of different sub-stances, is the most valuable.The positions of the spots usually limitidentification to a small number of possibilities, for which other means ofselection should ideally be available. It is clear that determination of theR, value alone is not as good a method of identification as is comparisonof the position of the unknown with those of other substances, preferablynearly related, run simultaneously on the same chr~matogram.~~ Thesymbols R, 53 and R, 54 have been used to denote the R, values relativeto those for tetramethyl glucose and proline, respectively, in recognition of49 Biochem. J . , 1947, 41, 590.50 Lancet, 1946,251, 637 ; Biochem. J . , 1947,41, 240 ; C. E. Dent and C. Rimington,51 Nature, 1948, 162, 29.62 R. Consden, A.H. Gordon, A. J. P. Martin, 0. Rosenheim, and R. L. M. Synge,53 F. Brown, E. L. Hirst, L. Hough, J. K. N. Jones, and W. H. Wadman, Nature,64 R. Raper and J. Shaw, ibid., 1948, 162, 999.ibid., p. 253.Biochem. J . , 1945, 39, 251.1948, 161, 720274 BIOCHEMISTRY.the fact that relative R, values are more reliable than absolute ones. Intwo-dimensional chromatograms of amino-acids, the general pattern ofspots leaves no doubt as to the identity of most of them ; in one-dimensionalstrips, identification is possible only with simple mixtures. When tissueextracts or partial hydrolysates, or, in general, any ill-defined mixture isexamined, many spots may require an ad hoc research for their identification.For revealing amino-acids, peptides, certain amines, and amino-sugars,ninhydrin (triketoindane hydrate) still holds pride of place.Acetic acid 55should be added if salts are present in the mixture to be analysed. Dent 7prefers to allow the colour to develop in a warm room, and later uses heatto reveal certain substances which react only when hot. Tables of R,values and colours with ninhydrin have been listed.’, 299 499 509 56The Pauli reagent may be used for tyrosine or di-iodotyrosine,7 his-tidine,” and histamine ; 7 Ehrlich’s reagent, dimethyla.minobenzaldehyde,may be used for tryptophan,3l and the Sakaguchi reaction for arginine 7, 521and streptomy~in.~~~ 58 Periodic acid with Nessler’s reagent may some-times be used for serine or thre~nine,~’ but the reaction is rather insensitive.For sulphur-containing amino-acids, potassium iodoplatinate 57, 59 orsodium azide and iodine 6o may be used.Carbohydrates, methylated carbohydrates, and other reducing substancescan be detected by ammoniacal silver nitrate; resorcinol and naphtha-resorcinol 62 give characteristic colours with carbohydrates. Acetonyl-acetone and Ehrlich’s aldehyde reagent have been used for amino-sugarslo3potassium ferricyanide for adrenaline-like substances,a and alkaline picratefor creatinine, and for creatine after its conversion into ~reatinine.~@ 65Ultra-violet light reveals many substances by fluorescence or quenchingof fluorescence, e.g., amino-acids,60, 66 pigments of petal extracts,llY 67flavins,68 pterins,Gg porphyrins,ll products of heated pr~teins,~O carbo-hydrates after heating with m-phenylenediamine hydrochloride.60 Ultra-6s R.Consden and A. H. Gordon, Natu&e, 1948,162, 180.6 6 R. Consden, A. H. Gordon, and A. J. P. Martin, Biochem. J., 1946, 40, 580;W. R. Middlebrook and H. Phillips, ibid., 1947, 41, 218; R. Consden, A. H. Gordon,and A. J. P. Martin, Biochem. J . , in the press; R. Consden, A. H. Gordon, A. J. P. Mar-tin, and R. L. M. Synge, Biochem. J., 1947, 41, 596; R. Consden and A. H. Gordon,Biochem. J., in the press (cf. Biochem. J . , 1948, 43, x) ; J. J. Pratt and J. L. Auclair,Science, 1948, 108, 213.6 7 R. Consden, A. H. Gordon, and A. J. P. Martin, Biochem. J . , 1946, 40, 33.6 s W. A. Winsten and E. Eigen, J . Amer. Ghem.SOC., 1948, 70, 3333.s9 H. M. Winegard, G. Toennies, and R. J. Block, Science, 1948, 108, 506.6o E. Chargaff, C. Levine, and C. Green, J . BioZ. Ghem., 1948, 175, 67.62 W. G. C. Forsyth, ibid., 1948, 161, 239.63 D. Aminoff and W. T. J. Morgan, ibid., 1948, 162, 578.134 W. 0. James, ibid., 1948, 161, 851.6 6 D. M. P. Phillips, ibid., 1948, 161, 153.67 E. C. Bate Smith, ibid., p. 835.69 P. M. Good and A. W. Johnson, ibid., 1949, 163, 31.7O A. R. Patton, E. G. Hill, and E. M. Foreman, Science, 1948,108, 659.S. M. Partridge, Nature, 1946, 158, 270.6s G. A. Maw, ibid., 1947, 160, 261.138 J. L. Crammer, ibid., p. 349MARTIN : PARTITION CHROMATOGRAPHY. 275violet absorption of material washed from strips has been used for identi-fication of nu~leotides.~~Purines have been detected by precipitation of mercury and conversionof this into the sulphide ; 7 l and choline by precipitation of phosphomolybdateand reduction of this to the blue complex.60Biologically active substances have been detected by means of platesseeded with bacteria, e.g., penicillin,309 y2 ~treptomycin,~~? 58 p ~ l y m i x i n , ~ ~and growth-promoting substan~es.~~D-Amino-acids can be destroyed on the chromatogram with D-amino-acid oxidase, which affords a method of distinguishing them from L-amino-acids.75 a-Amino-acids have been differentiated from other substancesgiving colours with ninhydrin by treating the paper with copper carbonatebefore development of the chromatogram; 76 a-amino-acid spots do notthen appear, or appear in a different place, the eopper complexes beingfaster running ; 29 other substances are unaffected.The use of electron diffraction 77, 78 or, better, X-rays 78 for the identi-fication of dried extracts of chromatogram spots by comparison withauthentic material, promises to be a powerful method.Although in manycases material from paper or solvent must be present in the washings, ithas not prevented crystallisation, on which this method depends. PerhapsA. Engstrom and B. Lindstrom’s X-ray method of elementary analysiscould also be employed.79Use of Radio-isotopes.R. M. Fink, C. E. Dent, and K. Fink 80 detected substances containingradio-isotopes by presenting the chromatogram to a Geiger counter, orsimply by laying it on a photographic plate, whereupon a radio-autographresults.The iodine isotope 1311 has been given to rats and man, and radio-active materials detected and identified on paper strips ;80y mono- anddi-iodo-tyrosine and thyroxine were all identified. Fink and Fink 82exposed Chlorella to light and 14C02 for 4 hours, an alcohol extract waschromatographed, and fatty material, glucose, glutamic acid, glycine,alanine, arginine, valine, proline, aspartic acid, serine, threonine, andvarious unidentified spots were seen.71 E. Vischer and E. Chargaff, J. Biol. Chem., 1947, 168, 781 ; see also Hotchkiss,ref. 45.72 W. A. Winsten and A. H. Spark, Science, 1947, 106, 192; see also Goodall andLevi, ref. 45.73 J. R. Catch, T. S. G. Jones, and S. Wilkinson, Biochem. J., 1948, 43, XXVII.74 W.A. Winsten and E. Eigen, Proc. SOC. Exp. Biol. Med., 1948, 67, 513; W. F. J.Cuthbertson and E. Lester Smith, Biochem. J., Proc., 1949.76 T. S. G. Jones, Biochem. J., 1948, 42, LIX.76 H. R. Crumpler and C. E. Dent, to be published.7 7 A. Polson, V. M. Mosley, and R. W. G. Wyckoff, Science, 1947, 105, 603.7 8 C. L. Christ, C. J. Burton, and M. C. Botty, ibid., 1948, 108, 91.79 Experientia, 1947, 3, 191. 80 Nature, 1947, 160, 801.K. Fink and R. M. Fink, Science, 1948, 108, 358; R. J. Block, Anal. Chem.,1948, 20, 281.82 R. M. Fink and K. Fink, Science, 1948, 107, 253276 BIOCHEMISTRY.Production of amino-acids after short exposure to 14C02 during photo-synthesis has been studied.83 It is concluded that 3- and 4-carbon acids,but not glutamic acid, are produced via pyruvic and oxaloacetic acids.With radioactive materials of high specific activity, quantities can bedetected many orders less than the one microgram required for most colourreactions, and identification with authentic non-radioactive material iseasily performed by mixed chromatograms, in which the coloured spot andthe radio-autograph spot must correspond in all details of position andshape.The ease with which the chromatogram can reveal unknownmetabolic products is noteworthy ; e.g., lysine labelled in the €-position with14C is changed in the body into a-aminoadipic a ~ i d . 8 ~ The turnover of labelledleucine in a liver peptide has been studied.85pIodophenylsulphony1 derivatives of amino-acids, containing 13117have been separated on paper, and quantitative analysis is possible byusing a Geiger counter 8s; 35S could also be used.The urine of rats fed with methionine labelled with 35S has been examinedby paper chromatography; the sulphur in the SO,-- peak was highlyradioactive.When benzene was injected a t the same time as the meth-ionine was given, radio-sulphur appeared mainly in the ethereal sulphatefraction, and if bromobenzene and methionine were fed together, radio-activity was divided between the SO,-- peak and another due to mer-capturic acid.Separations effected by Silica Columns.Acetamido-acids.-The partition chromatogram was introduced byMartin and Synge l6 in 1941 for the separation of acetamido-acids, pre-cipitated silica supporting an indicator solution being used, together withchloroform and a little butanol as mobile phase.Various indicators havebeen used.87 The method was developed by Gordon, Martin, and Syngefor acetamido-acids 28, 37, 87 and for acetylpeptides.8s Tristram 37 hasmade the most extensive analyses of various proteins; the method givesquantitative results for phenylalizniiie, leucine, isoleucine, valine, proline,alanine, and tyrosine. Methionine is subject to great error, probablybecause of oxidation.7, 42 The proportion of leucine to isoleucine has beendetermined by infra-red a b s o r p t i ~ n . ~ ~ Other acids may be determined inspecial cases.28j 87,9083 W. Stepka, A. A. Bonson, and M. Calvin, Science, 1948, 108, 304.84 H.Borsook, C. L. Deasy, A. J. Haagen Smit, G. Keighley, and P. H. Lowy,J . Biol. Chem., 1948,173, 423; 176, 1383.8 5 Idem, ibid., 174, 1041.8 6 A. S. Keston, S. Udenfriend, and M. Levi, J . Awaer. Chem. SOC., 1947, 69, 3151.87 A. H. Gordon, A. J. P. Martin, and R. L. M. Synge, Biochem. J . , 1943, 37, 79,8 8 A. H. Gordon, A. J. P. Martin, and R. L. M. Synge, ibid., 1943, 37, 92.89 S. E. Darmon, G. B. B. M. Sutherland, and G. R. Tristram, ibid., 1948, 42, 508.313 ; H. F. Liddell and H. N. Rydon, ibid., 1944, 38, 68.A. H. Gordon, A. J. P. Martin, and R. L. M. Synge, ibid., 1943, 37, 538; 8. Black-burn, R. Consden, and H. Phillips, ibid., 1944, 38, 25; R. L. M. Synge, ibid., 1945, 39,363MARTIN : PARTITION CHROMATOGRAPHY. 277Dinitrophenyl Amino-acids.--F.Sanger 91 and R. R. Porter and S ~ ~ n g e r , ~ ~using a variety of solvents, have separated dinitrophenyl amino-acids on silicacolumns. All the common dinitrophenyl amino-acids can be separated.Adsorption plays a significant part in the separations. The stability of thesesubstances to acid hydrolysis makes possible the study of free amino-groupsin proteins and peptides. Insulin and gramicidin S 91 and haemoglobins 92have been so studied, and also peptides liberated from insulin by oxidation.93Fatty Acids.-L. L. Ramsey and W. I. Patterson 94 and S. R. Elsden 95separated lower fatty acids (up to C,) on precipitated silica with waterand chloroform. Ramsey and Patters0n,~6 using methylisooctane, andMoyle, Baldwin, and S~arisbrick,~~ using chloroform-butanol mixtures andbuffer solutions on precipitated silica, have separated acids up to C,.Peterson and Johnson 32 used concentrated sulphuric acid on kieselguhrwith benzene, and separated acids up to Clo.Good accuracy is claimedfor all these methods.G. Howard and A. J. P. Marting7 have used silane-treated kieselguhrto make a column loaded with hexane, and aqueous methanol as mobilephase, for the separation of long-chain fatty acids.Other Organic Acids.-Isherwood 37 separated fruit acids quantitativelyon a precipitated silica column Ioaded with 0.5~-sulphuric acid, usingchloroform-butanol mixtures as mobile phase. The method has been usedto determine fumarate in animal tissues.98 Glutamic acid can be determinedafter conversion into pyrrolidonecarboxylic a ~ i d .~ 9Methylated Sugars.-Di-, tri-, and tetra-methyl glucose have beenseparated quantitatively by D. J. Bell on a silica column loaded withwater, chloroform-butanol being used as the mobile phase.Penicillin.-Penicillin was studied on silica columns with added solidbases by Catch, Cook, and Heilbron; 26 Levi 27, used phosphate bufferas the stationary phase. The method has been widely used with bothprecipitated silica and kieselguhr as support, and with ether, chloroform,and various esters as mobile phase, but very little of this work has beenpublished. The most convincing separation yet published is that byH. Fischback, T. E. Eble, and M. M~ndell,~ who show almost completeseparation of K, dihydro-F, F, and G penicillins.No quantitative methodon these lines has been described.have Miscellaneous Substances.-L. L. Ramsey and W. I. PattersonO1 Biochem. J., 1945, 39, 507; 1946, 40, 261.93 F. Sanger, Nature, 1948, 162, 491.Q4 J . Assoc. Off. Agr. Chem., 1945, 28, 644.B5 S. R. Elsden, Biochem. J., 1946,40,252 ; J . Exp. Biol., 1946, 22, 51 ; S. R. Elsden,O6 J. Assoc. Off. Agr. Chem., 1948, 31, 139.O B L. M. Marshall, J. M. Orten, and A. H. Smith, Science, 1948, 108, 92.O2 Ibid., 1948, 42, 287.M. W. S. Hitchcock, R. A. Marshall, and A. T. Phillipson, ibid., p. 191.Unpublished.W. E. Hanby and H. N. Rydon, Biochem. J., 1946, 40, 297.D. J. Bell, J., 1944, 473.W. R. Boon, C. T. Calam, H. Gudgeon, and A. A. Levi, Biochenz. J., 1948,43, 262.J .Arner. Pharm. Assoc., 1947, 38, 2. J . Assoc. 08. Agr. Chern., 1946, 29, 337278 BIOCHEMISTRY.separated a-, p-, y-, and 8-isomers and two other substances from commercialhexachlorocyclohexane ; precipitated silica holding nitromethane and n-hexane as mobile phase were used. A quantitative method for the y-isomerhas been based on thisq5 W. C. Evans and M. W. Partridge have quantit-atively separated various solanaceous alkaloids on kieselguhr columns loadedwith phosphate buffers, with ether as mobile phase.6 The anti-perniciousanaemia substance has been separated on various columns, including silicaand starch.'Separations effected by Paper Chromatograms.Amino-acids and Peptides.-The technique of Consden, Gordon, andMartin29 for amino-acid separation has been adopted with little modi-fication.Dent uses a collidine-lutidine mixture in place of s-collidine,and uses it before phenol, in his two-dimensional chromatograms. Othersolvents have been employed.8Methods for the identification of simple peptides separated by paperchromatography have been worked out by Dent 5O and by Consden, Gordon,and Martin.49 Most peptides containing only a few amino-acid residuesrun as satisfactorily on the chromatogram as do amino-acids. Basicpeptides are apt to form streaks and, for these, butanol-acetic acid mixturesare valuable.ll, The number of possible peptides is so large that positionalone forms a poor clue to identity; they have to be extracted and hydro-lysed, and the amino-acids identified on further chromatograms.Treat-ment with nitrous fumes before hydrolysis distinguishes the residue carryingthe free amino-group. Dinitrophenyl derivatives of amino-acids and peptidesmay be run on paper, and these serve also to identify the free amino-group.1°Amino-acids have been identified in potato lla and other plant tissues,l27 l3anthers, l3 pollen, l4 insects' hmnolymph, 543 l3 nuclear proteins, l5 viruses, l6bacteria,17 hypertensin,8 medullated hairs,18 alkali-treated trypsinand trypsin inhibitor,20 and pathological urine. 5O Methionine SS-dioxide and0. T. Aepli, P. A. Muter, and J. F. Gall, Anal. Chem., 1948, 20, 610.Quart. J . Pharm. Pharmcol., 1948, 21, 126.E. Lester Smith, Nature, 1948, 161, 638; E. Lester Smith and L. F. J. Parker,P.Edman, Arkiv Kemi, Min., Geol., 1945, 22, A , No. 3.T. S. G. Jones, Biochem. J., 1948, 42, LII; 43, XXVII.Biochem. J., 1948, 43, VIII.lo D. M. P. Phillips and J. M. L. Stephen, Nature, 1948,162, 152.11° C. E. Dent, W. Stepka, and F. C. Steward, ibid., 1947, 160, 682.l2 A. Allsopp, ibid., 1948, 161, 833.l3 L. F. La Cour and R. Drew, ibid., 1947,159, 307.l4 J. L. Auclair and C. A. Jamieson, Science, 1948, 108, 357.l6 J. N. Davidaon and R. A. Lawrie, Biochem. J., 1948, 43, XXIX.l6 R. Markham, R. E. F. Methews, and K. M. Smith, Nature, 1948,162, 88; A. Pol-17 A. Polson, Nature, 1948, 161, 351 ; C. E. Work, VIIIth Cong. de Soc. de Chim.l8 S. Blackburn, Biochem. J., 1948, 43, 114.1@ R. Cockburn, B. Drucker, and H. Lindley, ibid., p. 438.2o E.Work, ibid., 1948, 42, XLIX.son and It. W. G. Wyckoff, Science, 1948,108, 501.biol., Paris, 1948MARTIN : PARTITION CHROMATOGRAPHY. 279methionine S-oxide have been demonstrated in oxidised casein,50 sulphur-containing amino-acids derived from cystine in chemically treatedand a-amino-E-hydroxyhexoic acid in deaminated casein.21 Casein andbeef were shown to be absorbed principally as free amino-acids duringdigestion.22 Alanine was found during the bacterial breakdown of trypto-phan.ss Norleucine was shown to be absent from spinal nlethioninefrom Bence Jones protein,23 and hydroxylysine 24 from a leaf protein.Amino-acids were shown to be destroyed in heated soy gl~bulin.~O a-Amino-butyric acid has been found in plant l1 and animal extract^,^ y-amino-butyric acid in potatoes,ll taurine in bl00d,7 methylhistidine in dog’s urine,’ethanolamine-phosphoric acid and hydroxylysine-phosphoric acid in beef.25Partition chromatography has been used t o control fractionation byother methods.26Polymixin has been shown to be a family of peptides, having in com-mon threonine , cty-diaminobutyric acid,75 leucine, or phenylalanine and a,fatty acid. Peptides have been distinguished in partly hydrolysed wool 27and insulin 93 and in pathological urine.50The structure of gramicidin S has been examined; it was shown to bea cyclic penta- or deca-peptide containing equimolar amounts of valine,ornithine, leucine, phenylalanine, and proline.28 From a partial hydro-lysate, valylornithine, ornithyl-leucine, leucylphenylalanine, phenylalanyl-proline and, with less certainty, valylornithyl-leucine and phenylalanyl-pkolylvaline were identified on two-dimensional chromatograms.Some ofthese peptides were found also when using Sanger’s technique (dinitrophenylderivatives) on a partial hydrolysate fractionated by ionophoresis. Thesequence valine-ornithine-leucine-phenylalanine-proline may occur in acyclopentapeptide or twice in a ~yclodecapeptide.~~Hypertensin and peptides from liver 3O although theyseem to contain several amino-acids, run as fairly satisfactory spots onpaper chromatograms.Quantitative Analysis of Amino-acids.Moore and Stein 393 42 have made a thorough study of the starch columnRemoval of metals and can separate many of the amino-acids by its use.21 R.Gingras, E. Page, and R. Gaudry, Rev. Can. Biol., 1947, 6, 801.21@ C. E. Dent and J. R. Schilling, Biochem. J., 1948, 42, XXIX.22 E. A. Dawes, J. Dawson, and F. C. Happold, ibid., 1947, 41, 426.23 C. E. Dent, Biochem. J., Proc., 1949.24 J. W. H. Lugg and R. A. Weller, ibid., 1948, 42, 408.25 A. H. Gordon, Nature, 1948, 162, 778.26 R. L. M. Synge, Biochem. J., 1948, 42, 99; E. V. McCollum and A. A. Rider,Science, 1948,108, 11 ; T. H. Farmer, Sci. J. Roy. Coll. Sci., 1947,17, 27; J. D. Gregoryand L. C. Craig, J. Biol. Chem., 1948, 172, 839.27 A. J. P. Martin, Symposium on Fibrous Proteins, SOC. Dyers & Colourists,1946, 1 ; see also Consden, Gordon, and Martin, ref. 56 ; Consden and Gordon, ref. 56.28 See Synge, ref.90; Sanger, loc. cit., 1946, ref. 91.29 Consden, Gordon, Martin, and Synge, ref. 56.30 G. H. Tiskhoff, A. Zaffaroni, and H. Tesluk, J. Bid. Chem., 1948, 175, 867280 BIOCHEMISTRY.by treatment of the column with 8-hydroxyquinoline is one condition ofsuccess; great care in packing the column appears to be another. Theyhave also investigated the ninhydrin reaction and found conditions forusing it as an accurate colorimetric method.31 In their second paper theydescribe in detail the determination of phenylalanine, leucine, isoleucine,methionine, tyrosine, and valine. Butanol-benzyl alcohol is the mobilephase, which must include 0.5% of thiodiglycol to prevent oxidation ofthe methionine. Their method appears to give results as accurate as thoseattainable by any other, but is somewhat laborious; it has been appliedto a number of proteins.Polson, Mosley, and Wyckoff 77 have extracted the coloured ninhydrinspot with acetone from two-dimensional paper chromatograms and measuredthe density of colour.L. Naftalin 32 completes colour development by heat-ing with further ninhydrin after extraction. R. J. Block 33 separates neutral,acid, and basic fractions with ioa-exchange resins, and after chromato-graphy, measures the density of the spots directly on the paper. R. B.Fisher, D. S. Parsons, and G. A. Morrison34 report a quantitative methodfor amino-acids and carbohydrates based on measurement of the spotareas on a reflex photograph of the chromatogram; the photographs haveincreased contrast.A.J. Woiwod35 forms the copper complex of amino-acids from theextracted chromatogram and estimates colorimctrically ; Jones 75 andA. J. P. Martin and R. Mittelmann 36 determine the copper complex polaro-graphically. The last is the only method yet published in detail, and itis suitable only for simple mixtures. Further details and experience mustbe awaited before the usefulness of these methods can be assessed. Someof them seem too good to be true !A. Polson,37 by a simple visual comparison of a series of dilutions ofunknown and control mixtures on one- or two-dimensional chromatograms,determines all the common amino-acids quantitatively. Results for replicateruns, and comparison with microbiological assay of E. coli hydrolysates,are given.The results appear surprisingly good, differences exceeding 10 yobeing exceptional.An ingenious method, “ retention analysis,” has been described byT. Wieland and E. F i ~ c h e r . ~ ~ A solution of copper acetate in tetrahydro-furan is allowed to flow in the chromatogram at right angles to the directionof development, as in making a two-dimensional chromatogram. Thecopper complex of the amino-acid which is formed moves only slowly ornot a t all. The solvent front is denuded of copper locally and a V-shapedindentation is formed in the copper acetate front. Since the copper acetate31 J . Biol. Chem., 1948, 176, 367.32 Nature, 1948, 161, 763 ; seo also Proceedings of Symposium on Partition Chrom-33 Science, 1948, 108, 608.35 Ibid., p.169.37 Biochimica et Biophysica Acta, 1948, 2, 575.38 Naturwiss., 1948, 35, 29; T. Wieland, Angew. Chem., 1948, A , 60, 313.atography, Biochemical Society, 1949.34 Nature, 1948, 161, 764.s6 Biochem. J . , 1948, 43, 353MARTIN : PARTITION CHROMATOGRAPHY. 281solution is of constant composition the area of the V-shaped indentationis a measure of the amount of copper precipitated, and hence of the amino-acid present in the chromatogram spot. Finally, the copper front is ren-dered easily visible by treatment of the paper with dithio-oxamide (rubeanicacid, NH,=CS*CS*NH,), in acetone, and the area of the indentation is tracedon transparent paper and measured with a planimeter. The results on afew synthetic mixtures show errors not exceeding 4%.The principle ofthis method is obviously capable of application to a wide range of substances.So far, its use is described only on one-dimensional chromatograms andafter the acid, basic, and neutral amino-acids have been separated byionophoresis.Carbohydrates.Partridge G1, 39 was able to separate practically all the common carbo-hydrates from each other by using essentially the same conditions andsolvents as have been used for amino-acids but with addition of the useof butanol-acetic acid mixtures. Ammoniacal silver was used for detection.The occurrence of many different carbohydrates together is rare, so thattwo-dimensional chromatograms are not often needed. Colour reactionshave been developed by Forsyth.62 Jones and his colleagues 5 3 9 4O separatedmethylated sugars.They have also extracted sugars from the chromato-gram and performed quantitative determinations, using the Somogyireagent or determining formaldehyde after oxidation. J. R. Hawthorne 41has estimated extracted sugars quantitativclly by measuring excess ofreagent after oxidation by hypoiodous acid.These methods have been used for investigation of the blood group As~bstance,~3, 399 42 shiga polysa~charide~~ structure of cellulose ofmarine alga3e4 and the carbohydrate metabolism of micro-organisms.45Nucleotides and Related Substances.Vischer and Chargaff 71 have separated guanine, adenine, and xanthine,uracil and thymine by using a quinoline-collidine mixture. Extractedmaterial was identified by its ultra-violet absorption spectrum.Hotch-using butanol with ammonia, separated cytosine, uracil, adenineand thymine, cytidine, guanosine, adenosine and thymidine. The chromato-grams were cut across into narrow strips, each of which was extracted andthe extract examined for ultra-violet absorption. The method carried anerror of perhaps lo%, or less if binary mixtures were analysed.39 Biochenz. J., 1948, 42, 238 (with addendum by R. 0. Westall) ; ibid., p. 251.40 A. E. Flood, E. L. Hirst, and J. K. N. Jones, Nature, 1947,160, 86 ; T. G. HalsalI,E. L. Hirst, J. K. N. Jones, and A. Roudier, ibid., p. 899; L. Hough, J. K. N. Jones,and W. H. Wadman, ibid., 1948, 162, 448.41 Ibid., 1947, 160, 714.42 D. Aminoff, W. T. J. Morgan, and W. M. Watkins, Biochem.J., 1948, 43, XXXVI.43 HalsalI, Hirst, Jones, and Roudier, ref. 40.44 E. G V. Percivrtl and A. G. Ross, Nature, 1948, 162, 896.4 6 W. G. C. Forsyth and D. M. Webley, ibid., p. 160282 BIOCHEMISTRY.Crammer 68 has separated riboflavin phosphate, flavin adenine dinucleo-tide, and riboflavin from tissues. He and Good and Johnson 69 haveseparated pterins with butanol-acetic acid mixtures. Flavin productionby diphtheria has also been studied.46P. Reichard4' has used starch columns with butanol for separation ofribonucleosides.Separation of Miscellaneous Substances.Separation of penicillin on buffer-loaded paper is reported by Goodalland Levi30 and by Winsten and Spark.72 The penicillin was detected bylaying the chromatograms on agar seeded with a sensitive organism. Goodalland Levi 45 have developed the method quantitatively.Baker, Dobson,and Martin 45 have chromatographed on buffered papers the hydroxamicacids derived from penicillin. isoPropy1 ether-isopropyl alcohol mixtureswere used as mobile phase. The spots were revealed by their colour withferric chloride and could be extracted and determined colorimetrically .The errors are probably smaller than in the biological method, which mayhave advantages, however, in the detection of small percentages of otherpenicillins in one nearly pure penicillin.Winsten and Eigen 58 have studied streptomycin on paper, using Zyotoluenesulphonic acid as stationary phase and butanol with Zyo of piperidineas mobile phase. At least five antibiotics have been demonstrated in crudesamples of streptomycin.J.W. H. Lugg and B. T. Overell48 separated various organic acids byusing butanol-acetic acid mixtures and detected them by spraying withan indicator after drying the chromatogram. The behaviour of creatineand creatinine has been studied by G. A. 49 Two-dimensionalchromatograms of several substances, not amino-acids, but giving colourswith ninhydrin, are described by Dent.7Boldingha4 has separated the ethyl esters of long-chain fatty acids onpaper laden with 30% of vulcanised rubber latex, using methanol as mobilephase.Anthocyanins and related substances in petals have been extensivelystudied by Bate Smith.67, 5O Butanol-acetic acid is a favoured solvent.Chromatographic and fluorescent behaviour and colour reactions haveserved to distinguish a very large number of substances.The differentsubstances produced by different strains of the same species are easilyfollowed, and the methods should be of value in genetical studies.James G4 has separated adrenalin, noradrenalin, methyladrenalin, andrelated substances by using phenol.Four biologically active fractions have been separated from liver extractsand detected on agar seeded with Lactobacillus Z ~ c t i s . ~ ~46 A. J. Woiwod and F. V. Linggood, Nature, 1948,162, 219.47 Ibkl., p. 663.so E. C. Bate Smith, to be published; see also Proceedings of Symposium, etc.,61 Cuthbertson and Lester Smith, ref. 74.48 Ibid., 1947, 160, 87. 4D Biochem. J., 1948, 43, 142.ref.11SANGER: THE CHEMISTRY OF INSULIN. 283Inorganic Separations.Partridge and Westall 39 and Consden and Gordon 55 noticed the separ-ation, during phenol and collidine runs, of ions of the common inorganicsalts.Linstead and his colleagues 40j 52 have studied the behaviour of manymetals and can separate on paper strips, or packed columns of cellulose,the members of the following groups : (Ca, Ba, Sr), (Ni, Mn, Co, Cu, Fe),(Bi, Cd, Cu, Pb, Hg), (Al, Ga, In, Zn), (As, Sb, Sn), and the noble metals.M. Lederer 53 has also separated the last. A variety of solvents has beenused, and concentrated hydrochloric or nitric acid or other complexingreagents are present to make the metals soluble in the rather fatty mobilephases. After development and separation, the metals may be deter-mined by conventional means.A.J. P. M.4. THE CHEMISTRY OF INSULIN.Since the isolation of insulin in a crystalline form by J. J. Abel in 1926,it has become increasingly clear that the active principle is itself a protein,composed only of amino-acids. It has all the properties usually associatedwith proteins, and many attempts to discover a non-protein prostheticgroup have failed. The only non-amino-acid component of crystallineinsulin is a small amount of loosely bound zinc, which is necessary for theformation of crystals. The chemistry of insulin is thus part of the widerproblem of protein Chemistry and it is the methods of protein chemistrythat have been most effective in the study of its structure. This reviewtherefore deals with the study of insulin as a protein, and attempts toillustrate the methods now available for investigating proteins and tosummarise our present knowledge of its structure.No attempt is made todeal with the physiological aspects of insulin action and emphasis is laidonly upon the more recent developments. A number of reviews of theolder literature 2, 3 j 49 and on the physiological aspects 2, 6~ ‘ 9 *, areavailable.62 R. P. Linstead, Discussion on New Techniques, Chemical Society, Nov. 25th,1948; F. H. Burstall, G. R. Davies, R. P. Linstead, and R. A. Wells, Nature, 1949,163, 64.63 Ibid., 1948, 162, 776. Proc. N a t . Acad. Xci., 1926, 12, 132.H. F. Jensen, “ Insulin; Its Chemistry and Physiology,” New York, 1938.V.du Vigneaud, J . Washington Acad. Xci., 1937, 27, 365; Cold Spring HarborA. White, ibid., 1938, 6, 262.H. Fraenkel-Conrat, Ann. Rev. Biochem., 1943, 12, 276.Xymp. quant. Biol., 1938, 6, 275.6 D. W. Hill and F. 0. Howitt, “Insulin; Its Production, Purification and Physio-S. Soskin and R. Levine, “ Carbohydrate Metabolism,” University of Chicagological Action,” Hutchinson’s Scientific and Technical Publications, 1936.Press, 1946.8 J. P. Bouckaert and C. de Duve, Physiol. Rev., 1947, 27, 39.T. F. Gallagher, Ann. Rev. Biochem., 1948, 17, 3532 84 BIOCHEMISTRY.The Moleculm Weight of Insulin.-Using the ultracentrifuge, G. L.Miller and K. J. I. Andersson l o found a molecular weight of 46,000 forinsulin. Recent determinations in the ultracentiifuge l1 and by osmoticpressure l2 confirm this in giving a value of 47,000--48,000 for 0-5-1-0%solutions of insulin a t pH 7, though the molecule dissociates in acid oralkaline solutions.13, l4 In contrast to these values D.Crowfoot l5 cal-culated the size of the unit cell from X-ray measurements and deduced amolecular weight of 36,000. This unit cell possesses trigonal symmetry,indicating that it is built up of three identical or almost identical units ofmolecular weight 12,000. The simplest explanation l4 of these results isthat the real molecular weight of insulin is in fact 12,000, and that in solutionfour such units are loosely bound to form molecules of molecular weight48,000, whereas in the crystals three such units are combined in the unitcell.Confirmation for this theory was obtained by Gutfreund,l4 who showedthat on dilution and in acid solutions the molecular weight is lowered,indicating dissociation, and by combining the two effects he was able todemonstrate a minimum molecular weight of about 12,000. This figurewas also found by A. C. Chibnall l6 to be the lowest value for the molecularweight that would fit all the figures for the amino-acid analyses.Probably the first to put forward a value of this order for the molecularweight of insulin was F, Lindner,17 who isolated a compound of insulinwith a basic protein from fresh pancreas. This complex, which he con-sidered to be the genuine depot insulin or “ nativinsulin,” had a molecularweight of 15,000--20,000, indicating that it was built up of one moleculeof insulin of molecular weight about 10,000 combined with a basic protein.He also showed that protamine-zinc-insulin, the complex formed by coni-bination of protamine with insulin, had a lower molecular weight thaninsulin.Using the ultracentrifuge in a study of the effects of detergents oninsulin, G.L. Miller arid K. J. L. Andersson found that when insulinwas dissolved in a 2% solution of the detergent, “ Dupanol ”, it formed aggre-gates with the ‘‘ Dupanol” which had the molecular weight 27,600. Themicellar weight of the dupanol was 12,500, suggesting a molecular weightof the order of 15,000 for the insulin present in these aggregates.There is thus considerable evidence that the real molecular weight ofinsulin is 12,000, and that in relatively concentrated neutral solutionsaggregates of 4 molecules of insulin are formed, which dissociate on dilutionand a t extreme pH values.On crystallisation 3 molecules form the unitlo J . Biol. Chem., 1942, 144, 459.l1 H. Gutfreund and A. G. Ogston, Biochem J., 1946, 40, 432.l2 H. Gutfreund, ibid., 1948, 42, 156.13 B. Sjogren and T. Svedberg, J. Amer. Chem. SOC., 1931, 53, 2657.l4 H. Gutfreund, Biochem. J., 1948, 42, 544.l5 Proc. Roy. SOC., A , 1938, 164, 580.l6 J . SOC. Leather Trades’ Chem., 1946, 30, 1.Med. u. Chem., 1942, 4, 248; Chern. Abs., 1945, 39, 1731.l8 J . Biol. Chem., 1942, 144, 475SANQER: THE CHEMI3TRT OF INSULIN. 285cell, and in the presence of a detergent or basic protein, complexes areformed containing one molecule of insulin.These changes are summariseddiagrammatically in Fig. 1.The ‘‘ Heat Precipitation ” of Insulin.-When insulin is heated in weaklyacid solutions it forms an insoluble precipitate which is physiologicallyinactive.lg7 2oa 21 This ‘( heat precipitate ” can, however, be re-activatedby treatment with dilute alkali to give a regenerated product which appearsto be identical with the original insulin.22 The ability to form a “heatprecipitate ” appears to be a unique property of insulin, and is dependenton the intact structure of the molecule.0 - XF I G . 1.Recently Waugh 22t z31 24 has studied this reaction in some detail, andhas demonstrated that it takes place in two stages. The first stage ischaracterised by the formation of fibrils, and the second by the aggregationof these fibrils to form spherites. These spherites are the visible ((heatprecipitate.” By heating insulin a t pH 2-5 a thixotropic gel is producedwhich consists of fibrils having lengths of about 20,000~.and widths ofabout 1 5 0 ~ . In stronger acid (O.lN-HC1) these fibrils aggregate to formspherites in which the fibrils are statistically oriented radially. The natureof the spherites produced depends on the lengths of the fibrils. Thus shortfibrils will form compact, well-oriented spherites, whereas long fibrils formbadly oriented spherites or may only form a gel.Waugh concludes that the fibrils are actually formed by the endwiselinkage of the globular units of insulin, and that the molecule is not unfoldedlS V.du Vigneaud, E. M. K. Geiling, and C. A. Eddy, J . Pharm. Exp. Ther., 1928,33, 497.20 T. D. Gerlogh and R. W. Bates, ibid., 1932, 45, 19.21 V. du Vigneaud, R. H. Sifferd, and R. R. Sealock, J . Bid. Chenz., 1933, 102, 521.22 D. F. Waugh, J . Amer. Chem. SOC., 1948, 70, 1850.23 I. Langmuir and D. F. Waugh, ibid., 1940,62, 2771.24 D. F. Waugh, ibid., 1946, 68, 247286 BIOCHEMISTRY.in any way. This reaction is thus distinguished from the more usual typesof denaturation in which globular proteins appear to unfold in a randommanner before aggregation. In fact insulin is generally regarded asbeing incapable of denaturation, until the -S-S- bridges, which are pre-sumed to hold together the relatively short chains, are broken.25 Sinceheat precipitation takes place in acid solution, where insulin is largelydissociated into molecules of molecular weight 12,000, it would seem prob-able that it is the endwise linkage of these units rather than those ofmolecular weight 48,000 which forms the fibril.The various changesinvolved in the “ heat precipitation ’’ reactions are summarised in Fig. 1.Amino-acid Composition of Insulin.-As already indicated, insulin isbuilt up of amino-acids. The estimation of the amount of the differentamino-acids present is thus of fundamental importance and the first stepin investigating the chemical structure of the molecule. Insulin has beenshown to contain all the amino-acids that are usually found in proteinsexcept tryptophan, methionine, and the rarer amino-acids hydroxyprolineand hydroxylysine.Compared with other proteins insulin has an unusually high sulphurcontent.It was early realised that most of this was present in the formof cystine residues,26 but there was considerable doubt as to whether all thesulphur was due to cystine or whether there was some other sulphur-con-taining amino-acid present in insulin. This was suspected since, underthe usual conditions of estimation by the specific Sullivan method, all thesulphur could not be accounted for as cystine. The nature of the sulphurpresent was of particular interest since it appeared that the physiologicalactivity depended on maintaining the state of linkage of the sulphur intact,and it was suspected that a new sulphur compound might be concerned inthe “ active centre ” of insulin.However, thorough searches especially bydu Vigneaud and his collaborators3 have not yet revealed any sulphur-containing residue other than cystine. In fact G. L. Miller and V. duVigneaud 27 were able to show that all the sulphur could be accounted foras cystine by the Sullivan procedure if the hydrolysis were carried out in amixture of hydrochloric acid and formic acid instead of the conventional20 yo hydrochloric acid, which caused incomplete hydrolysis and the destruc-tion of certain labile cystine residues.B. Kassell and E. Brand2* showed that a small amount of volatileiodide was produced on treatment with hydriodic acid by the Baernsteinprocedure, suggesting the presence of methionine.However, V. du Vig-neaud, G. L. Miller, and C. J. R ~ d d e n , ~ ~ using the more specific homo-cysteine thiolactone method for estimating methionine, were able to showthat it was absent, and found that the volatile iodide was not methyl iodide,z 5 K. M. Rudell, “ Symposium on Fibrous Proteins,” The Society of Dyers &2 6 V. du Vigneaud, H. Jensen, and 0. Wintersteiner, J . Pharm. Ezp. Ther., 1928,27 J . Biol. Chem., 1937, 118, 101.2B J . Biol. Chem., 1939, 131, 631.Colourists, 1946, 15.32, 367.28 Proc. SOC. Exp. Biol. Med., 1936, 35, 444SANGER: TRE CHEMISTRY OF INSULIN. 287and that the amount produced was greatly reduced by hydrolysis of theprotein, suggesting that it was due to certain labile groupings, the nature ofwhich is still unknown.Methods for the analysis of the different amino-acids have now reacheda stage of development where it is possible to determine all the naturally-occurring amino-acids with considerable accuracy.Probably the mostthorough and accurate analyses of insulin are those carried out byG. R. T r i ~ t r a m , ~ ~ H. T. Ma~pherson,~~ and M. W. ReesS2 in Chibnall'slaboratory. These workers have used the most reliable methods avail-able, and where possible have used different methods for estimating thesame amino-acids, and have carried out careful control analyses with amino-acid mixtures. A preliminary, though thorough, analysis has been carriedout by E. Brand33 and his collaborators, who have made extensive use ofmicrobiological methods.As these were not used by the former workersthey constitute a valuable check, especially for the monoamino-acids,where very few methods are available. In the table are summarised whatare believed to be the most reliable figures for the composition of insulin.Composition of Insulin.Nitrogen as yo of Number of residuesAmino -acid. protein-nitrogen. per molecule.Arginine ........................... 6.35 2Histidine ..................... 8.55 4Lysine 3.10 2Glutamic acid .................. 11.4 15Aspertic acid .................. 4.5 6Amide-N ........................ 8.98 12Cystinel2 ........................ 9.36 12Tyrosine ........................ 6.5 9Alanine ........................... 4.4, 4.75 7Valine ........................... 6.0, 6.8 8P henylalanine ..................4.4, 4.3 6Serine ........................... 4.45 6Threonine ........................ 1.57 2Leucine ........................... 8.95, 9.2 12isoLeucine ..................... 1.98, 1.83 3Glycine ........................... 5.2, 5.5 7Proline ........................... 2.0, 2.3 3...........................Ref.313131343332271630, 3530, 3330, 33323233, 3633, 3616, 3330, 33The nitrogen accounted for is 986% of the total protein nitrogen, indi-cating that the analysis is almost complete. In assessing the accuracy ofthe results it must be remembered that it is impossible to carry out a com-plete control experiment, the chief unknown factor being the breakdownof amino-acids when in peptide form during hydrolysis.In most casesthis is probably negligible, but it may be that for certain amino-acids itis different from the breakdown of the free amino-acid. Apart from this30 Biochem. J . , 1946, 40, 721.32 Ibid., p. 632.34 A. C. Chibnall, M. W. Rees, and E. F. Williams, Biochem. J . , 1943, 37, 372.35 A. S. Keston, S. Udenfriend, and M. Levy, J . Amer. Chem. SOC., 1947, 69, 3151.a6 S. E. Darmon, G. B. B. M. Sutherland, and G. R. Tristram, Biochem. J., 1948,31 Ibid., p. 470.33 Ann. New York Acad. Sci., 1946, 47, 187.42, 508288 BIOCHEMISTRY.unknown factor it is probable that the figures for arginine, histidine, lysine,amide-N, serine, and threonine are accurate to 2-3%, and for the otheraniino-acids to about 5%.The figure for cystine was determined froin thetotal sulphur, which should be accurate to 2yo, assuming all the sulphuris in fact in cystine. In column 3 of the table the results have been calculatedto the nearest whole number as the number of residues of each amino-acidper insulin molecule of molecular weight 12,000. This gives an overallpicture of the composition, and these figures would probably not be affectedby the slight errors involved in the analyses.Besides the amino-acids, crystalline insulin contains a small amount ofzinc, which appears to be necessary for the formation of crystal^.^' Thiszinc can be replaced in the crystals by cobalt, nickel, or cadmium.38 Scottand Fisher 38 originally estimated the amount of zinc present in crystallineinsulin as 0.52% or 3 atoms per unit cell of molecular weight 36,000; how-ever, E.J. Cohn, J. D. Ferry, J. J. Livingood, and M. H. Blanchard 39 haveshown that, according to the method of crystallisation, amounts of zincvarying from 0.3 to 0.6% could be introduced, but that on repeated washingof the crystals the zinc content fell to about 0.3-0.35%, which correspondsto 2 atonis of zinc per unit cell. Crystals have also been prepared having0.15% zinc or one atom per unit ce11,40 so that it would appear that thezinc content cannot be regarded as a reliable constant of insulin. It isonly loosely bound to the molecules in solution since it can be completelyremoved by electrodialy~is,3~ and it seems doubtful whether it plays anyimportant role in the structure of the active principle.Further Details of Insulin Structure.-Insulin is exceptional amongproteins in that it has a very high content of free a-amino-groups.Thata t least one of these was located on a phenylalanyl residue was demon-strated by H. Jensen and E. A. who isolated the phenylhydantoinof phenylalanine from a hydrolysate of insulin that had previously beentreated with phenyl isocyanate. In order to obtain more complete inform-ation about the free amino-groups of insulin and other proteins and peptides,a method was worked out for the identification and estimation of the amino-acids on which these groups were located using 1 -fluoro-2 : 4-dinitroben~ene.4~When this method was applied to insulin it was found that two free amino-groups were on phenylalanyl residues, two on glycyl residues, and two onthe E-amino-groups of the lysine residues, making a total of six free amino-groups, four of which are a-amino-groups.I n this way it has been possibleto locate the position of four of the amino-acid residues in insulin in the" terminal " position, and by carrying the method further and using partialhydrolysis it is possible to locate a few more residues which are near to theterminal re~idues.4~ Thus the presence of the following amino-acid sequences3 7 D. A. Scott, Biochem. J., 1934, 28, 1592.3 8 D. A. Scott and A. M. Fisher, ibid., 1935, 29, 1048.39 J. Amer. Chenz. Sroc., 1941,63, 17.41 Ibid., 1935, 108, 1.43 Idem, Nature, 1948 162, 491.40 M.Sahyun, J . BioE. Chem., 1941,138,487.42 F. Sanger, Biochern. J . , 1945, 39, 507SANGER: THE CHEMISTRY OF INSULZN. 289alanine terminal residues and all the amino-.--..--.acids that are found in insulin. From thesulphur distribution between the two fractionstwo structures for the insulin molecule wereThese two structures are shown inFig. 2, where the full lines represent the peptidechains, and the broken lines the -S-S- bridges.The acid chains with glycyl terminal residues (u) @Iare marked G, arid the basic chains wit'h F I G . 2.phenylalanyl terminal residues are marked P.Results from experiments with monolayers of insulin suggest that thestructure a is the most probable. When spread on an air-water interface,insulin forms a monolayer of 7-9 A.thickness, that is the average thicknessof one polypeptide chain,46 and the spread material can be recovered inan active form. Structure b would not be expected to form a monolayerof this thickness without rupture of an -S-S- bridge, which would not occuron spreading, and would cause inactivation. Thus it would seem that thestructure represented in Fig. 2a is the most likely structure of insulin, andthe simplest way of explaining the facts that have so far been accumulated.Another niethocl of approaching the problem of insulin structure, whichshould prove useful, is to break down the molecule in a specific mannerwith pure proteolytic enzymes and to analyse the structure of the break-down products.This method has been used by J. A. V. Butler, D. M. P.Phillips, and J. &I. L. Stephen,47, 48 who showed that, when insulin is44 Fed. Proc., 1948, 7, 200.4 6 A. Rothen, B. F. Chow, R. 0. Greep, and H. B. van Dyke, CoZd Spring HarborSymp. quant. Biol., 1941, 9, 272.48 J. A. V. Butler, E. C. Dodds, D. M. P. Phillips, and J. AT. L. Stephen, Biochem.J., 1948, 42, 116, 122.45 F. Sanger, Nature, 1947, 160, 295.4 7 Nature, 1948, 162, 418.REP.-VOL. XLV. 290 BIOOEEMISTRY.digested with chymotrypsin for a short period, i t is broken up into a numberof small peptides and a “ core,” which is precipihble by trichloroaoetiaacid. This core has a molecular weight of about 5,000, and is electro-phoretically homogeneous. It contains SCr-90~0 of the total sulphur ofinsulin and has no, or only traces of, arginine, proline, Chreonine, andghenylalanine, and most of the terminal residues are glycine. It thusresembles, in some ways, the acidic fraction obtained by oxidation ofinsulin, though the exact interpretation of these data is not clear at present.Rdation between Strucbe and Physiological Activity.-A large amouqtof work has been done, especially by Freudenberg and his collab-o r a t ~ r s , ~ ~ r 503 513 52 in attempts to determine which groups of the insulinmolecule are responsible for its physiological activity.On the assumptionthat there was some small “active centre” or prosthetic group on themolecule, it was hoped to determine its structure, and obviate the necessityof elucidating the complete structure of the protein.While this hope isstill far from being realised, these experiments have shown that certaingroups are essential for activity, whereas others are not. The chief methodof approach to this problem was to treat the insulin with a reagent, whichreacted as far as possible specifically with a single type of group, and totest the activity of the product.One disappointing conclusion that must be drawn from these experi-ments is that the intact polypeptide structure of the molecule appears t o -be essential for physiological activity. In no way has it been possible t~split off an active fraction from the rest of the molecule. As soon as anypeptide bonds are broken by enzymic 509 53, or acid 49 hydrolysis or any-S-S- bridges are broken by reduction 5 2 ~ 55, 56 or 52 theinsulin is irreversibly inactivated. This makes the hope of being able tosynthesise an active insulin a rather remote one.Treatment of insulinwith specific reagents has, however, indicated that not all of the insulinmolecule is in fact essential for activity, and suggests tbat there may be asmall active centre on the molecule composed o f a number of gmuphgsin a particular arrangement.When insulin is treated with keten a t pH 6, the free amino-groupsare completely acetylated in about five minutes, and no other groupappear to have reacted. On prolonged action of keten the phenolichydroxyl groups of the tyrosine residues also react. K. G. Stern andA. White 57 showed that if only the amino-groups are acetylated the insulinis still active, whereas acetylation of the phenolic hydroxyl groups causes49 K.Freudenberg, W. Dirscherl, and H. Eyer, 2. physiol. Chenz., 1931, 202, 128.6o K. Freudenberg, W. Dirscherl, H. Eichel, end E. Weiss, ibid., p. 159.61 K. Freudenberg and H. Eyer, ibid., 1932, 213, 226.62 I<. Freudenberg and T. Wegman, ibid., 1935, 233, 159.53 A. F. Charles and D. A. Scott, Tpans. Roy. SOC. Canada, 1930, 24, V, 95.64 A. M. Fisher and D. A. Scott, J . BioZ. Chew., 1934, 108, 289.G 6 V. du Vigneeud, A. Fitch, E. Pekarek, and W. W. Lockwood, ibid., 1931, Q4,233.6 6 K. G . Stern 4nd A. White, ibid., 1937,117, 96.6 7 Ibid., 1938, 122, 371SANBER: THE UHEMISTRY OF INSULIN. 291inactivation. This inactivation could be reversed by removing the O-acetylgroups with dilute alkali.It thus seems that the free amino-groups arenot essential for activity, whereas the phenolic hydroxyl groups are essential.The essential nature of the phenolic hydroxyl groups was also demon-strated by C. R. Harington and A. Neuberger 58 who showed that, wheninsulin was iodinated by a method which appeared to substitute only inthe tyrosine residues, it was inactivated, and removal of the iodine byreduction caused some reactivation.Other groups that appear to be essential are the free carboxyl groups.Esterification of these groups by alcohols in the presence of acids causesinactivation, which may be reversed by removal of the ester group indilute Such treatment is believed to be specific for carboxylgroups, and not to cause any splitting of peptide bonds.61 The inactiv-ation of insulin by diazoniethane49 is also probably due to reaction withcarboxyl groups.If insulin is treated with concentrated sulphuric acid a t --So, an insulinsulphate is produced, in which the aliphatic hydroxyl groups of the serineand threonine residues are substituted.62 This derivative was found to beactive,60 showing that the aliphatic hydroxyl groups are not essential.This treatment introduced extra acidic groups into the molecule so that itcan be concluded that neither the net charge nor the ratio of acidic to basicgroups in the molecule is important in determining biological activity.Several workers have demonstrated that formaldehyde causes theinactivation of i n ~ u l i n , ~ l ~ 63 but the reaction of formaldehyde with proteinsis extremely complicated 64 so that it is difficult to draw any definite con-clusions from most of their results.Recently, however, H. Fraenkel-Conrat and H. S. Olcott 65 have shown that a t pH 11-12 formaldehydereacts irreversibly only with the amido- and the guanidino-groups of theprotein. Insulin so treated was still active,66 indicating that neither ofthese groups is essential.Thus in trying to obtain a picture of the “active centre ” responsiblefor the activity of insulin it would seem that it contains carboxyl andphenolic hydroxyl groups, whereas amino-, aliphatic hydroxyl, amido-,and guanidino-groups are presumably not involved. An intact state of the-S-S- groups and the peptide bonds is probably essential to maintain thespecific configuration of the active groupings.No information is available4996 8 Biochem. J., 1936, 30, 809.59 F. H. Cam, K. Culhane, A. T. Fuller, and S. W. F. Underhill, ibid., 1929,233, 1010.6o 11. B. Glendening, D. M. Greenberg, and H. Fraenkel-Conrat, J . Biol. Chem.,61 H. Fraenkel-Conrat and H. S. Olcott, ibid., 1945, 161, 259.62 H. C . Reitz, R. E. Ferrel, H. Fraenkel-Conrat, and H. S. Olcott, J . Amer. Chem.63 D. A. Scott, J . Biol. Chem., 1925, 65, 601.64 D. French and J. T. Edsall, “ Advances in Protein Chemistry,” 1945, 2, 278.6 6 J . Biol, Chem., 1948, 174, 827.6 6 H. S. Olcott and H. Frmnkel-Coarat, Chem. Reoiws, 1947, 41, 168.1947, 167, 125.SOC., 1946, 68, 1024292 BIOCHEB!USTRY.to decide whether the glyoxaline groups of the histidine residues or the non-polar side-chains of the monoamino-acids are essential for biological activity.These latter groups cannot be entirely ignored.Although they cannot beinvolved in electrostatic or hydrogen bonds they may form specific typesof bonds due to van der Waals forces, which may play anin specific reactions between large molecules.5. TW3 CHEMOTHERAPEUTIC APPROACHES TO THE T.B.The chemotherapy of tuberculosis implies a simplifiedimportant partF. S.PROBLEM.concept whichmay have been compromised in the reader’s mind by association withpre-knowledge restricted to the application of successful chemotherapy inother microbial diseases, On the otherhand, no other host-parasite relation has been the subject of such detailedenquiry a t the hands of pathologists,l bacteriologists, chemistsy25 andothers.These studies have emphasised the most destructive nature of theparasitism, the remarkable collaboration of parasite and host in the deathof the host’s vital tissues, and the unsolved riddle of delayed lysis of caseoustissue with its capacity to spread infection. Appreciation of the unusualpathology of this normally self-limiting chronic disease has emphasisedthe desirability of approaching the problem of elimination of the parasiteon a broad front. It will be convenient for our present purpose first todescribe the nature of the biochemical lesions which the observed pathologicalchanges indicate, and from this basis to review the present advances.Usually, by the time the disease is identified clinically it has estab-lished its characteristic pathology, the tubercle, and this is so even in itsmore acute manifestations.* The minimal clinical lesion visualised, forexample, by X-ray shadows, represents destructive changes and reflects,as we shall see, at least two biochemical lesions.The Origin of the Tubercle and its Ultimate Fate.-The tubercle is thecharacteristic but not unique lesion of the disease : typical epithelioid celltubercles are seen in sarcoid, leprosy, tularemia, schistosomiasis, andsyphilis.Many studies of all stages of the development of tubercles enablean unequivocal description to be given.h Within a few minutes of anexperimentally induced infection, a normal mononuclear phagocyte ingestsa (single) invading tubercle bacillus.The cell increases in size, its nucleusenlarges, and it becomes an epithelioid cell.5 Next, fusion of severalepithelioid phagocytes takes place to give a Langhans giant cell with itsThis is not of itself a bad thing.1 A. R. Rich, “ The Pathogenesis of Tuberculosis,” Charles C. Thomas, Springhld,la Idem, ibid., Chap. 18.Illinois, 1944.H. G. Wells and E. R. Long, “ The Chemistry of Tuberculosis,” Ballibre, Tindall,R. J. Anderson, Physiol. Rev., 1932, 12, 166.F. R. Sabin and C. A. Doan, J . Exp. Med., 1927, 46, 627.and Cox, 1932.4 A. R. Rich and H. A. McCordock, Bull. Johm Hopkins Hosp., 1933, 52, 5BROWNLEE: APPROA(3HES TO THE T.B.PROBLEM. 293numerous nuclei arranged in a “rosette,” or there may be formed theless frequent “ foreign-body giant cell ” in which the nuclei are scattered.Within 3 or 4 days a small nodule is built up by clustering epithelioid cells,shown by Metchnikoff 6 to be simply altered monocytes. Since the nodulegrows progressively after access to blood-borne phagocytes is cut off, it isbelieved that the phagocytes multiply in situ. Gradually the adjacenttissue cells are pushed aside, dying from nutritional deficiencies caused bypressure of the expanding tubercle. At this stage of development collagenfibres are formed between the epithelioid cells. Should multiplication ofthe bacillus be held in check, no necrosis is observed, and with the deathof the tubercle bacilli the transfer to collagen becomes progressive, thetubercle becoming fibrous so that only a nodule of fibrous tissue finallyremains. Complete resolution and disappearance of the tubercles hasbeen frequently reported, and this is also true of large tubercles whichhad proceeded to central caseatioii in guinea-pigs.7 Should multiplicationproceed, the central portion dies and becomes necrotic.Permeability of the !bbercle.-Important from any consideration ofchemotherapy is whether tubercles and associated caseous tissue are readilypermeable. points to the inherent evidence of viable tubercle bacilliand host cells dependent upon diffusible nutrilites for their continuedsurvival, and to the frequency with which central foci become calcified.Much additional evidence is now available from chemotherapeutic studieswith diaminodiphenyl sulphone derivatives such as promin 8 and sulphetroneand of the positive evidence of diffusibility derived from successful strepto-mycin therapy in miliary tuberculosis of man.lO Brownlee has foundsulphetrone to penetrate normal and caseous tissue of man with equalfacility.10, 11Hypersensitivity and Necrosis.-Alt,hough the death of host cells appearsto follow to some degree the lodgment of the foreign body which thetubercle also is, it is now known that the widespread tissue destructionwhich characterises the disease follows the conditioned hypersensitivityinduced by the products of metabolism of virulent pathogens.The proteincomponent is known to be responsible, and appears to be identical withtuberculin which is harmless to the nornial insensitive animal but is adeadly poison to the sensitised host.All that is known of this mechanismconfirms the opinion that the clinical disease in all its manifestations followsfrom the phenomenon of hypersensitivity. Actively multiplying organismsappear to be essential, and virulence in this connection connotes a capacityto multiply.Caseation.-Liquefaction of body cells after their death is the normal7 L. U. Gardner, ibid., 1922, 6, 163.* M7. H. Feldman, F. C. Mann, and H. C. Hinshaw, ibid., 1942, 46, 187.lo A. H. Baggenstoss, W. H. Feldman, and C. H. Hinshaw, Amer. Rev. Tuberc.,l1 Q. Brownlee, Lancet, 1948, ii, 131.RichW.B. Soper, Amer. Rev. Tuberc., 1917, 1, 385.G . Brownlee and C . R. Kennedy, Brit. J . PharmacoZ., 1945, 3, 29.1947, 55, 54294 BXOCHEMISTRY.prerequisite for disposal by phagocytes and is a, function of proteolyticenzymes contained in the cells. In the characteristic tuberculous lesion,only partial autolysis occurs, and the necrotic cells lose structure, outline,and nuclei to become, together with their intercellular materials, a formless“ caseous ” mass. Opinion is divided on the reason for incomplete digestion.E. L. Opie and B. I. Barker l2 showed that active enzymic function couldbe identified with the onset of caseation but subsequently ceased, whetherbecause of absence or inactivation was not proved. J. W. Jobling andW. Petersen l3 found the soaps of unsaturated fatty acids extracted fromtubercle bacilli inhibited in witro the proteolytic activity of the leucocyticenzymes.On the other hand, caseation is characteristically observed inman in infections with micro-organisms which attract mononuclear phago-cytes, for example, in typhoid but not in the allied colon bacillus infectionswhich attract polymorphonuclear phagocytes. It is of great interest thattypical caseation follows the necrosis of “ lipoid pneumonia ” which resultsfrom the accidental introduction of, for example, cod-liver oil into the humanlung. An outpouring of mononuclear phagocytes characterises these lesionsalso.la The predominance of mononuclear phagocytes in caseous lesionsinduced the comparison of Weiss and Czarnetzky l4 between the proteolyticenzyme activity of the two types of cell.The monocytes of rabbits con-tained one proteinase, pepsin with an optimal activity a t pH 3, whereasthe polymorphonuclears contained pepsin, cathepsin, and trypsin withoptima a t pH 3, 5 4 , and 8 respectively.Softening.-!L’he “ softening ” of caseous lung substance allows imprisonedtubercle bacilli to be discharged into the air-passages and thus to infectnew sites. I n contrast to caseous areas, a remarkable characteristic ofsoftened areas is the large number of tubercle bacilli they contain. Itseems logical to attribute the lysis of caseous material to enzymic action,but this is unproven. Tubercle bacilli are known to be poor in proteolyticenzyme content? and the current view appears to attribute the reneweddigestion to the activity of infiltrating polymorphonuclear leucocytes whichare commonly identified in freshly softeningFate of the Caseous Lesion.-Should the tubercle bacilli die, the caseousarea may become encapsulated by connective tissue, or it may be resolved.This surprising observation is now well documented.16, 1 7 9 l8Cdciflcation.--The calcium phosphate which is deposited in caseousareas has the same composition, Ca,(PO,),, as that of normal bone,2 and,apart from the suggestive indications that high serum calcium and phos-phorus concentrations influence calcium deposition,19 as, for example, in18 J .Exp. Med., 1914, 19, 645.14 C. Weiss and E. J. Czarnetzky, Arch. Path., 1935, 20, 233.16 P.Huebschmann, “ Pathologische Anatomie der Tuberkulose,” Julius Springer,18 H. S. Willis, Amer. J . Roehtgenol., 1934, 31, 721.17 E. R. Oppenheimer, Bull. Johns Hop- Hosp., 1935, 57, 247.18 H. E. Burke, Amer. Rev. Tuberc., 1922, 6, 591.1D J. K. Bullock, Amer. J . Dw. Child., 1930, 40, 725.l3 Ibid., p. 383.Berlin, 1928BROWNLEE : APPROACHES TO THE T.B. PROBLEM. 295children generally, and that phosphataseF0 and vitamins A21 and D playan important but as yet undisclosed part, no final comment can be madeon the conditions governing deposition of calcium in necrotic tissue.Mode of Action of the Tubercle Bacillus.-We are now in the positionto examine three important biochemical reactions conditioned by the host-parasite relation and to enquire further into the activity of the specificsubstances involved.(a) The bodies of infecting tubercle bacilli contain substances whichresist degradation by the ordinary defensive mechanisms and are treatedby the host in an unusual way.Instead of being engulfed by polymorpho-nuclear leucocytes and carried to the lymph nodes for digestion and elimin-ation they are absorbed in situ by monocytes which may subsequently beconverted into a tubercle. It is noteworthy that this is the beginning ofa usually successful self-limiting process, and it is tempting to regard it asa protective device on the part of the host. Numerous observers 22* havebeen sufficiently impressed by the non-toxicity of multiplying virulenttubercle bacilli for normal tissue, or in tissue-culture preparations, todescribe the association as symbiosis.Nevertheless, the immunity of thebacillus within the monocyte and, should multiplication ensue, the sub-sequent production of caseous tissue appear to indicate a common bio-chemical lesion associated with specific enzyme inhibition.( b ) The tubercle bacillus produces no pharmacological poison, either ofexotoxic origin excreted during the life of the bacillus or of endotoxicnature liberated by lysis after its death. Should multiplication ensue, aproduct of metabolism induces hypersensitivity of adjacent host cells withthe result that an otherwise innocuous product becomes a poison responsiblefor the death of cells. This remarkable host-parasite collaboration isresponsible for most of the clinical manifestations of the disease.(c) During infection the host may develop a capacity to modify thecourse of the disease-an acquired resistance.The Chemical Composition of Tubercle Bacilli and the Biological Activityof their Components.-The status of our knowledge concerning chemicalcomposition up to 1932 is collected and admirably summarised by Wellsand Long.2 Subsequent to this, F.R. Sabin23 reported the biologicaleffects produced by the lipins fractionated by R. J. Anderson24 and hiscolleagues from standard strains of acid-fast bacteria 24 grown under care-fully standardised conditions of synthetic media, choice of containers andconditions of growth. A complete bibliography of this work is available.25Anderson 24 fractionated, under CO,, the lipin fractions from acid-fastbacteria into a phosphatide extracted by alcohol-ether, an acetone-soluble" fat," and a chloroform-soluble " wax." The amounts extracted and20 G.H. Bell, Brit. Med. Bull., 1945, 3, 76.21 (Sir) E. Mellanby, Proc. Roy. SOC., 1944, B, 132, 28.28 A. A. Maximow, J. Infect. Dis., 1924, 34, 549.as Physiol. Rev., 1932, 12, 141.26 D. C. White, Nat. Tuberc. Ass. Teo., Series No. 9, New York, 1929.24 Ibid., p. 166296 BIOCHEMISTRY.TABLE I.Lipin fractions from acid-fast bacteria.Type of organism.Timothy02145G. %.18.7 0.59H ~ a n H-37.G. yo.Phosphatide 253.1 6.54Acetone-sol-uble fat ... 240.0 6-20Chloroform-soluble wax 427.0 11-03Total lipoids 920.1 23.78Dry bacillaryresidue., ....2902.0 75.01Dry bacterialmatter perculture ...... 1,928Avian 531.G. yo.79-7 3.26Bovine 1698.G. %.60-5 1-55Leprosy 370.G. %.100.5 3-2077.3 2-19 131.7 3-34 87.4 2.75 289.5 6.47379.5 10.79538.5 15.26336.0 8-52528-2 13.40158.4 4.98264.5 8.37444.8 9.98834.6 18.72942.7 83.71 3370-1 85-50 2783.1 87.70 3389.8 80.381-757 2,318 1,983 1,488their distribution among acid-fast bacteria are shown in Table I adaptedfrom his account.24 The ‘‘ wax ” fraction is a complex phosphatide; itseparates into a high- and a low-melting fraction. The high-melting fractionis hydrolysed with difficulty to give an acid analogous to phthioic acid anda polysaccharide ; there is also phosphorus and glycerol. The other fractionyields numerous glycerides of saturated fatty acids of the phthioic acidseries, The acetone-soluble “ fat ” contains neither phosphorus nor nitrogen,and yields a carbohydrate and numerous fatty acids on hydrolysis.Theacids present are butyric, palmitic, stearic, cerotic, linoleic, linolenic, tuber-culostearic, and phthioic. This acetone fraction proved to be the bestsource for the characteristic €atty acids of the tubercle bacillus which arepresent in predominating amounts.The products of the acid hydrolysis of the phosphatide are given inTable 11.TABLE 11.Cleavage products (yo) from bacterial phosphatides.HWan.Total ether-soluble ..................... 6-67Palmitic acid ........................... 30.5Oleic acid after reduction to stearic 12.8acid ....................................12.8Liquid saturated fatty acids pre-sumably mixtures of tuberculo-stearic and phthioic ............... 20-9Total fatty acids recovered ......... 64.2Water-soluble constituents ......... 33-34Mannose ................................. 9.2Inosite (inositol) ........................ 8.9Other sugars ........................... 12.3Glycerophosphoric acid ............... 5.4Avian.55-5618.418.418.4Bovine.57-5827.07.07.0Timothy. Leprosy.60 62-220.0 18-65.6 13.85.6 13-814.153.746-4713.33.016.050.043-446.73-518.0 13.543.6 45.940.0 38.09-5 5.22-2 0.620.610.0 6-0 9.9From the acid hydrolysis of the phosphatide has been obtained a homo-logue of stearic acid, named tuberculostearic acid, subsequently shown bySpielman to be 10-methylstearic aeid, and found to be without biologicalactivity.= There were also separa.ted (+)- and (-)-hexacosanic a.cidsBROWNLEE : APPROACHES TO THE T.B.PROBLEM. 297C2,H,,02, named phthioic acid, of which only the (+)-acid had biologicalactivity.23Analogous but optically inactive acids with biological activity 23 wereextracted from the lipins of avian and bovine tubercle bacilli, and fromleprosy bacilli and timothy-grass bacilli.% There was also evidence ofsmall amounts of higher acids. More recent evidence indicates the presencein human tubercle bacilli of many branched-chain fatty acids not hitherto28, 29 N. Polgar 3O has presented an improved scheme forseparating the acids, which are first converted into acetonyl esters and theninto semicarbazones which are then crystallised ; from this treatment fournew acids emerge. Recent evidence pointed to the lilrelihood that Ander-son’s phthioic acid was a mixture, probably of two acids.31 N.Polgar and(Sir) R. Robinson 32 synthesised a number of niethyl-substituted long-chainacids, and a review of the chemical and physical cvidence together with thelrnowledge of its biological activity 33 prompted a preference for 3 : 13 : 19-trimethyltricosanoic acid as “ phthioic acid. ”Acid-fastness.-A large group of organisms of which the tubercle bacillusis one, resist decolorisation with acids after being dyed with aniline dyes.This property is retained by the “ waxy ” fraction, and of that complexby an acid of high molecular weight named “ mycolic acid.” 249 54 Certainevidence points to the fact that the physicochemical state of mycolic acidwithin the bacillus contributes to acid-fa~tness.~~9 56Biological Properties of the Isolated Lipins.-In the hands of Sabin andher colleagues 349 359 23 all three of Anderson’s 24 lipin fractions, but no otherfraction, protein or carbohydrate, produced tubercles.Of these the phos-phatide was most active in giving epithelioid giant cells and subsequentcaseation, and this applied to phosphatide from human, avian, bovine,timothy-grass, and lepra bacilli, in that order of biological activity.23 Theonly other substance among the controls which “ acts just like the tuberculo-phosphatide ” 23 is lecithin.Tuberculostearic acid was found to be irritatingbut did not produce tubercles. (+)- but not (-)-Phthioic acid producestypical tubercles. Sabin23 has refuted the suggestion of C. H. Boissevainand C. T. Ryder36 that bacillary debris accounted for the phosphatideactivity. Still others3’ are critical of the specific activity of the phos-phatide being attributable to phthioic acid. Of more moment is the criticismof Rich who points to the disproportionate amounts of phosphat8ide and27 C. 0. Edens, M. M. Creighton, and R. J. Anderson, J . Biol. Ch,em., 1944,154, 587.R. L. Peck and R. J. Anderson, ibid., 1941,138, 135.29 L. G. Genger and R. J. Anderson, ibid., 1944, 156, 443.30 Biochem. J., 1948, 42, 206.31 Sir R.Robinson, personal communication, 1949.33 J. Ungar, C. E. Coulthard, and L. Dickenson, Brit. J . Exp. Path., 1948, 29, 382.34 F. R. Sabin, C. A. Doan, and C. E. Forkner, J . Exp. Med., 1930, 52, suppl. 3.35 F. R. Sabin, K. C. Smithburn, and R. M. Thomas, ibid., 1935, 62, 771.36 Amer. Rev. Tuberc., 1931, 24, 751.37 K. Bloch, Biochem. Z., 1936, 285, 372.32 J., 1945, 359298 BIOCHEMISTRY.phthioic acid needed to produce tubercles and caseation compared with theobservable depredations of a single bacillus. For example, the phosphatidefrom 300 mg. of bacilli produced a little caseation in 1 of 4 guinea-pigsinjected intraperitoneally and in each of two receiving the amount from8.0 g. of bacilli.38 More recently Ungar, Coulthard, and Dickenson 33 foundthe synthetic 3 : 13 : 19-trimethyltricosanoic acid of Polgar and Robinson 32to be more active than crude (+)-phthioic acid from human tubercle bacilliin the production of tubercle-like granulomata which “ corresponded in somerespects to the description by Sabin, Doan, and Forkner.” 34 Of 15 syntheticacids tested, 10 were as active as or more active than the natural product.The most active synthetic substance was 3 : 12 : 15-trimethyldocosanoicacid which showed granulomata with as little as 10-25 mg.in a singleintraperitoneal dose suspended in aqueous alcohol. The surface layer ofprecipitated phthioic acid analogues is no doubt very different from thatof the continuous film of the intact bacillus. Realisation of this factprompted J.Ungar 39 to observe the chemiotactic response of macrophagesto agar blocks in which these acids were entrained and then subsequentlyimplanted in the peritoneal cavity of guinea-pigs. The first cells to penetratewere polymorphonuclear leucocytes and lymphocytes ; then came monocyteswhich engulfed the particles and became typical epithelioid cells. Ungarhas made some preliminary observations which if confirmed will shed lighton the quantitative aspect of the responses of phthioic acid and its analogues.39He coated killed colon bacilli with 3 : 13 : 19-trimethyltricosanoic acid, andinjected the suspension intraperitoneally into guinea-pigs ; the subsequentgranulomata of the omentum and elsewhere were indistinguishable fromthose of killed tubercle bacilli simultaneously injected into controls, anddiffered entirely from the minor reactions observed in control animals injectedwith suspensions of colon bacilli.Biological Significance of the Carbohydrates.-Appreciation of theimmunological significance of the bacterial carbohydrate of the pneumo-coccus as a result of the studies of Avery and Heidelberger, and in particularthe association between host-virulence and kind of capsular carbohydrate,the relation between pneumococcal anaphylactic hypersensitivity and carbo-hydrate, and the demonstration that effective immunity to the pneumo-coccus is that developed against the carbohydrate has directed interest tothe carbohydrate content of the tubercle bacillus.The tuberculocarbohydrates isolated by Johnson, Coghill, Brown, andRenfrew,23 the polysaccharides isolated from the lipins by Anderson,24and the carbohydrate isolated from media by Long and Seibert 23 werestudied by Sabin.23 Their biological activities appeared to be restrictedto a chemiotactic and damaging effect on leucocytes.It has no power toinduce hypersensitivity,N but can act as a hapten.*l That is to say, unlikes8 K. C. Smithburn and F. R. Sabin, J . Exp. Med., 1932, 56, 862.39 Personal communication, 1949.40 F. R. Sabin, A. L. Joyner, and K. C. Smithburn, J . Exp. Med., 1938, 68, 563.4L P. P. Laidlaw and H. N. Dudley, Brit. J . Ezp. Path., 1925, 6, 197BROWNLEE : APPROACHES TO THE T.B. PROBLEM. 299the pneumococous-specific carbohydrate:2, 43 the tuberculocarbohydratedoes not stimulate antigen formation, or induce protection, but is capableof reacting in precipitin tests with sera from infected hosts.41 A criticalbiological re-examination of the three different specific polysaccharides isoverdue.M. Heidelberger and A. E. 0. Mizel 69 found the principal sero-logically active cell component ([.ID +85O) to contain D-arabinose andwmannose, and later found a second specific somatic polysaccharide oflower dextr~rotation.~O~ 71 (Sir) N. Haworth, P. W. Kent, and M. Stacey 729 73similarly isolated a somatic polysaccharide of [cc]F +85" together with adeoxyribonucleic acid derivative and glycogen and, also, a polysaccharideof [ct]gO +25" closely associated with the cell lipins.Biological Significance of the Proteins of the Tubercle Bacillus.-Anumber of proteins have been extracted from the tubercle bacillus 24 andone from the medium in which it is grown.2 In their purest formsthese proteins have practically no toxicity for the uninfected body,44 butare lethal in extremely small doses for the tuberculous subject, as was firstdemonstrated by Koch for impure '' tuberculin." 45 The innocuous natureof purified tuberculoprotein for non-sensitised cells was demonstrated in anelegant way in tissue-culture preparations by Rich and Lewis46 and con-trasted with its lethal effect on similar cells from tuberculous hypersensitiveThus, although innocuous for the normal, it is highlytoxic for the tuberculous hypersensitive body, causing necrosis, fever, severeconstitutional symptoms and even death.l These facts, first demonstratedby K o ~ h , 4 ~ have been repeated many times49 and have been redemon-strated in a most convincing fashion by Seibe13,~~ using " pure " tuber-c~lin.~O Thus while hypersensitivity is demonstrably a response to proteinwithin the bacillus no convincing evidence has been offered that this hyper-sensitivity can be induced in the normal animal with the protein itself.Only whole bacilli, living or dead, successfully initiate tuberculin hyper-sensitivity.The tuberculoproteins are antigenic,51, 529 53 but they haveno protective capacity.Acquired Resistance.-While infection with the tubercle bacillus doesnot confer the stable and solid protection acquired after diphtheria orsmallpox, there is little doubt that a significant degree of protection is4 7 7 4842 0.T. Avery and W. F. Gobel, J . Exp. Med., 1933, 58, 731.c3 L. D. Felton, 77.8. Publ. Health Repts., 1938, 63, 1855.44 F. B. Seibert and B. Munday, Amer. Rev. Tuberc., 1931, $33, 23.45 R. Koch, Deut. med. Woch., 1891, 17, 101.46 A. R. Rich and M. R. Lewis, Bull. Johns Hopkins Hosp., 1932, 50, 115.47 J. D. Aronson, J . Exp. Med., 1931, 54, 387.4 8 J. K. Moen and H. F. Swift, ibid., 1936, 64, 339.49 E. R. Long and F. B. Seibert, Arner. Rev. Tuberc., 1926, 13, 448.50 F. B. Seibert, ibid., 1941, 44, 1.62 L. Deinnes, J . Immunol., 1929, 17, 85.63 M. Pinner, Amer. Rev. Tuberc., 1928, 18, 497.64 F. H. Stodola, A. Lesuk, and R. J. Anderson, J . Biol.Chem., 1938, 126, 605.65 T. H. C . Benians, J . Path. Bact., 1912, 17, 199.66 H. Sherman, J . Infect. Dis., 1913, 12, 240.61 F. B. Seibert, ibid., 1930, 21, 370300 BIOCHEMISTRY.attained.l Although widespread agreement exists that the living, attenuatedbovine bacillus of Calmette (BCG) 58 confers recognisable acquired resist-ance in laboratory animals, there has been more reluctance to accept theclaims for heat-killed tubercle vaccine. A meticulous and critical reviewerlike Rich,l writing in 1944, speaks of the established fact doubted for years,and quotes numerous successful investigator^,^^^ 60, 61y 62 yet S. Raffel 57is unable to satisfy himself that a heat-killed vaccine confers resistance.In the Reporter’s laboratory, G. Brownlee and C.R. Kennedy 63 foundthe A. S. Griffith and R. E. Glover’s glycerol-killed vaccine 64 to be littleless effective than a BCG living vaccine.TABLE 111.Immunological responses in guinea-pigs to the attenuated tubercle bacillus, anda tubercle vaccine and its chemical fragments.Acquired Purifiedresist- tuberculinPreparation injected. ance. responses. Biochemical lesion associated with.b. Chemiotaxis of monocytes 1.22- 65c. Inhibition of proteases 14d. Hypersensitivity and inducede . Skin aller,ay 5 71. BCG 58 + + a. AcTired resistance 65lethal effect 45* 12. Suitably prepared vac-3. L c wax ) ) 24 - + a. Chemiotaxis to monocytes 239 331 394. Phosphatide 24 - - As 5 below5.+ + As 1 above cine 69, 60, 61, 62, 63b. Inhibition of proteases 14c.Skin allergy 57a. Chemiotaxis to monocytes 23* 339 SB Phthioic wid ” 249 3% 81,32- - b. Inhibition of proteases l4( ? inhibited /3-oxidation 6 6 )6. Crystalline protein 51 - - a. Hypersensitivity and induced7. Polysaccharide 23n 24 - - a. Cherniotaxis of leucocytes 23lethal effect 4 5 3* “ Wax ” contains bomd pr0tein.lElimination of the Parasite.-hdirect approach. Attempts to demon-strate acquired resistance with BCG and killed vaccine in the laboratoryanimal (Table 111) have probably also been successful for man (BCG65)(killed vaccine 67). However, no recombination of the known chemicalfragments has yet proved successful. It appears that the antigenic complexwhich confers resistance is labile and readily destroyed by chemical mani-5 7 Amer.Rev. Tuberc., 1946, 54, 564.5 8 A. Calmette, Bull. Inst. Pasteur, 1924, 22, 593.59 A. Boquet and R. Laporte, Compt. rend. SOC. Biol., 1937, 124, 1159.60 W. Pagel, J . Path. Buct., 1937, 44, 643.61 R. M. Thomas, J . Exp. Med., 1933, 58, 227.62 B. Lange, R. Freund, and E. Jochimsen, 2. Hyg., 1927,107, 426.63 Unpublished data, 1949.65 K. N. Irvine, “ The B.C.G. Vaccine,” Oxford University Press, London, 1934.66 Sir R. Robinson, Nature, 1946, 158, 815.6 7 G. G. Kayne, Amer. Rev. Tuberc., 1936, 34, 10.64 J . Comp. Path., 1939, 52, 57BROWNLEE : APPROACHES TO THE T.B. PROBLEM. 301pulation. Renewed attempts, as, for example, by the extraction of livingcells with urea solutions, probably a t low temperatures , appear justified.The synthetic or semisynthetic approach may prove amenable, since theidentification of the precise chemical causal agent associated with thebiochemical lesion observed in the tubercle may have already occurred inthe substance a t present labelled 3 : 13 : 19-trimethyltricosanoic acid,32but of greater significance is the uncovering of synthetic analogues ofenhanced biological 66 Similarly the lipin-bound polysaccharideof Sir N.Haworth, P. W. Kent, and M. Stacey 72 appears to be a hapten 41of high specificity, and the crystalline protein of Seibert is a knownArtificial Antigens.-Not only can the specific acids, protein, and carbo-hydrate of the parasite be recombined, but they can be linked, individuallyor in combination, to antigenically significant proteins, with the object ofimproving upon the natural antigen which confers active resistance.Inthese reactions, not only the protein carrier but the nature of the chemicallinkage has proved significant. Landsteiner successfully applied Pauly'sreaction 74, 75, 76 to couple proteins with diazonium compounds and obtainedchemically defined specificities. This has proved a very flexible methodbut has been criticised a,s yielding an unnatural linkage. S. H. Hopkinsand A. Wormall 77, 789 79 coupled isocyanate derivatives of the hapten toprotein a t a pH near neutrality to give substituted ureas, and in yet anotherapproach L. Pillemer, E. E. Ecker, and J. R. Wells 8o introduced haptensto proteins the disulphide groups of which had been reduced to thiol,a method applicable to a cystine-containing protein like tuberculin.Haring-ton and his colleagues 82, 83 coupled haptenazides to the amino-groupof protein so that the final link was of a peptide nature. A stimulatingknown example of non-specific protection is that given by the antigenscontaining azobenzyl glucosides of the synthetic gentiobiuronic, cello-biuronic, and glucuronic acids which evoke in rabbits the production ofantibodies capable of conferring passive immunity in mice against multiplelethal doses of virulent Type I1 pneumococci without specific agglutininsor precipitins being demonstrable in the rabbit antisera.88 It has beenclearly demonstrated that antibodies raised in response to injected antigensneed not be protective, as is the case with the known chemical fragmentsof the tubercle bacillus, and, conversely, as shown by the anti-antigen.51, 52, 53G3 A.Boquet and L. NBgre, Ann. I m t . Pasteur, 1923, 37, 787.70 M. Heidelberger and A. E. 0. Menzel, J . Biol. Chem., 1937, 118, 79.71 Idem, ibicl., 1939, 127, 221.74 A. Pauly, 2. physiol. Chem., 1904, 42, 508.7 6 Idem, ibid., 1905, 44, 159.7 7 Biochem. J., 1933, 27, 740.78 Ibid., 1934, 28, 227.R. F. Clutton, C. R. Harington, and M. E. Yuill, Biochem. J., 1938, 32, 1111.82 Idem, ibid., p. 1119.8a G. C. Butler, C. R. Harington, M. E. Yuill, and A. A. Miles, ibid., 1940, 34, 838.Proc. BOG. Exp. Biol. N.Y., 1932, 29, 631.7a J., 1948, 1211, 1220.76 Idem, ibid., 1915, 94, 284.IbirE., p. 1706.J .Exp. Med., 1939, 69, 191302 BIOCHEMISTRY.hormones,@* 859 86~ 87 the neutralisation of physiological activity need notbe associated with in vitro demonstration of the characteristic propertiesof an antigen. This is unfortunate since protection experiments withtubercle-bacilli infections are costly and very time-consuming.I n the Reporter's laboratory, G. Brownlee and R. Friedmann 89 pre-pared artificial antigens from oleic, palmitic, and stearic acid, and from'' phthioic acid " and " total phthioic-like acid.'' Well-defined crystallineazides were obtained with stearic and palmitic acid, and these were coupledto horse-serum globulin and to the high-sugar fraction of alburnen,m andalso, for absorption tests, to gelatin. Although the complexes were antigenic,they retained no hapten specificity.Oleic acid, " phthioic acid," and" total phthioic-like acids " did not give identifiable azides, but gave com-plexes by coupling their acid chlorides to the same protein carriers at analkaline pH. Of these, probably only the " total-phthioic-like acids " andoleic acid retained hapten specificity, and oleic acid was best.Four of these antigens, BCG living vaccine, H,,RV glycerol-killedvaccine, oleic acid-globulin, and " total phthioic acid-like acids " formedthe basis of a guinea-pig protection comparison. The infecting strain wasa virulent human tubercle bacillus, " Carstairs "-H,,RV was deliberatelyavoided-which gave an average infected life of 30 weeks in the controlanimals. The final basis of comparison was a " tuberculosis index " 91based upon the distribution of the disease in affected organs and its histo-logical significance in addition to factors like duration of infected life.Theartificial antigens were without protective action, while the BCG and theglycerol-killed H,,RV vaccine conferred similar and significant resistance.Arising out of considerations of the metabolic requirements of bacteria,of the acid-fast group, more fully discussed below, it appearss2? s3 thatnaphthaquinones may be implicated. The possibility of interference withessential metabolites or growth factors on the basis of substrate competitionis now well ap~reeiated,9~, s5 but the possible intervention of antibodiesraised in vivo in response to artificial antigens containing the metaboliteas hapten is an alternative weapon.With the starting point of phthiocol, the yellow pigment of humantubercle bacilli,96? 97 G.Brownlee and R. Priedmann 98 prepared albumen,8p B. Zondek and F. Sulman, Proc. SOC. Exp. Biol. N . Y . , 1937, 37, 343.86 M. Van den Ende, J . EndocrirwL, 1941, 2, 403.G. B. Collit, H. Selye, and D. L. Thompson, Biol. Rev., 1940, 15, 1.87 H. L. Thompson, J . Exp. Res., 1922, 43, 37.W. F. Goebel, J . Ezp. Ned., 1940, 72, 33. 89 Unpublished data.L. F. Hewett, Biochm. J., 1937, 31, 1047.91 G. Brownlee and C. R. Kennedy, Brit. J. Pharmacol., 1948, 3, 37.92 F. W. Twort and G . L. Ingram, " Johne's Disease," BalliBre, Tindall and Cox,93 D. W. Woolley and J. R. McCarter, Proc.SOC. Exp. Biol. N.Y., 1940, 45, 357.94 D. D. Woods, Brit. J . Exp. Path., 1940, 21, 74.96 P. Fildes, Lancet, 1940, i, 955.96 R. J. Anderson and M. S. Newman, J . Biol. Che?ia., 1933, 103, 197.g7 I-, ibid., 1940, 136, 211.London, 1913.a@ Unpublished dataBROWNLEE : APPROACHES TO THE T.B. PROBLEM. 303globulin, gelatin, and egg-albumen antigens to a series of 12 syntheticanalogues of phthiocol. Hapten specificity was probably never enooun-tered in this series, and no compound was subjected to animal protectionexperiments .Direct Approach.--“ Protective capsule.” The slow growth of thetubercle bacillus, its marked hydrophobic properties, and its persisteiice inthe host have raised a concept of a continuous protective lipoid ca,psule.laYet, after a first isolation on an egg-enriched medium, freshly isolatedtubercle bacilli grow on a simple medium containing glycerol as a carbonsource, asparagine as a source of nitrogen, phosphates, and a magnesiumsalt.99~ lo0 Inexacting in its nutritional requirements, the adapted organismappears to restrict its growth factors to magnesium and phosphorus, whichtogether with an alcohol and an aliphatic amino-acid (amide), water, andoxygen, all readily diffusible water-soluble substances of poor lipin solu-bility, constitute its needs.There is, however, little doubt that the lipin-protein-carbohydrate complex constituting the cytoplasmic matrix iscapable of resisting the passage of quite simple ions into the cell, sinoe thetubercle bacillus maintains its internal environment within a very broadrange of acidity and basicity.lOl Contact with 10% sulphuric acid for anindefinite period does not kill, 18% hydrochloric acid kills jn 5 hours and1% in 24 hours, while 5% acetic acid kills in less than 30 minutes.lo2Equally impressive concentrations of bases are required to kill; 32%sodium hydroxide in 24 hours, or 40% in 4 hours.Barium and calciumhydroxide similarly are non-lethal.lo2 Phospholipins inhibit the toxicaction of many antiseptics on bacteria; lo3 for example, small amounts ofcephalin protect Gram-positive bacteria against gramicidin in vitro and inviwo, and histones or protamines are able to combine chemically with activegroupings of the lipoid complex of Gram-negative bacilli and thus renderthem susceptible to tyrothricin or typical detergents which are otherwiseinactive in these conditions.lo3In ~ i t r ~ Tests.-There is poor correlation between in vitro tests forantiseptic activity and subsequent chemotherapy, a problem which isaggravated by the slow growth and unexacting metabolic requirements ofthe tubercle bacillus.2, lol, lo2 R.J. Dubos lo3 contrasts the few substancesactive in vivo, and notes the limited, delicate, specific injury, directed, inthose cases of which meagre information is available, against anabolic,synthetic processes, or steps in cellular division. In contrast, the bludgeonof antisepsis is directed to catabolic processes, or to anabolic and catabolicindiscriminately. Reliance upon in vitro test alone would have preferredaromatic amines and nitroso-derivatives to sulphonamides, toxic quinonesgg Proskauer and Beck, from W.H. Feldman and H. C. Hinshaw, Amer. Rev.Tuberc., 1945, 51, 582.loo E. R. Long and F. B. Seibert, ibid., 1926, 13, 393.lol H. B. Richardson, E. Shorr, and R. 0. Loebel, Trans. Nat. Tuberc. Ass. N . Y . ,lo2 C. 0. Guss and M. 0. Kloetzel, Nat. Res. Coun. Lit. Survey, U.S.A., 1948.lo3 “ The Bacterial Cell,” Harvard University Press, 1945.1931, 205304 BIOCHEMISTRY.and phenols to penicillin, and tyrocidine to gramicidin, and would haverejected arsphenamine out of hand.lO3 Older methods of increasing thegrowth-rate involved enrichment of the medium lo4$ lo5 and more recentlyR. J. Dubos lo6, lo7 demonstrated that oleic acid in the form of a sorbitanester or combined with albumen promoted rapid diffuse growth.A lessdesirable attack on the same problem is the substitution of other rapidlygrowing organisms for the tubercle bacillus lo8 as test objects. R. L.Mayer log has similarly suggested the use of members of the family of fungiincluded under the Actinomycetes, but most workers have been unwilling tosubstitute any organism for the human tubercle bacillus.ll0 A secondinherent disadvantage of the in vitro test is the uiiricillingness of the organismto reproduce in unfavourable circumstances. G. P. Youinans 111 introduceda method whereby established growth in the shape of very large suspensionsis exposed to prepared drug dilutions, and, in both submerged and surfaceculture, growth therefrom is measured.IR viuo-in vitro Test.-A test which appears to overcome many of thedisadvantages of the in vitro test was described by Brownlee.ll0 A toxicdose of the test substance or the largest amount which can be introduced,whichever is smaller, is injected intraperitoneally in oil or other suitablesuspension into a guinea-pig of about 550 g. After two hours, orbefore if the animal shows symptoms, it is anaesthetised with chloroform,the thorax is opened, and about 3 C.C.of blood is drawn aseptically fromthe still beating heart. The citrated blood is diluted in serial incrementswith equal volumes of Long's agar contained in previously stoppered Lambethtubes. These are " sloped " and sown with one drop (0.01 c.c.) of a uniformsuspension of tubercle bacilli containing 0.5 mg.per C.C. Incubated a t37-5", the degree of inhibition, compared with that due to a standard sub-stance such as diaminodiphenyl sulphone or streptomycin, enables a practicalanswer to be given with avian strains in 6 days and with bovine and humanstrains in 21 days. Thechemotherapeutic activity of the blood is directly measured in terms of astandard substance of known chemotherapeutic activity. Usually it ispossible to determine the blood concentration microbiologically or chemically,and in other cases the observation rests on the practical basis of a bloodconcentration which is optimum since it produces symptoms of acute toxicityor is derived from the maximum quantity it is possible to inject.In vim Tests.-Several established animal tests are in use 110 such asthose with guinea-pigs, mice, or hamsters, the last two in an attemptto reduce the time factor.H. Schwabacher and G. S. Wilson 112 intro-The test seems to have the following advantages.lo* H. Cooper and N. Myei, J . Lab. Clin. Med., 1928, 13, 469.lo5 R. D. Herrold, J. Infect. Dis., 1931, 48, 236.lo8 Proc. SOC. Exp. Biol. N.Y., 1945, 58, 361.lo7 J. Exp. Med., 1946, 83, 409.lo8 P. D'Arcy Hart, Brit. Med. J., 1946, 11, 805.log Rev. Medicale, 1941, Nov.-Dee. 3.110 G Brownlee, Re@. Internat. Cong. Microbiol., 1947, 209.ll1 Tubercle, 1944, 18, 442. na Proc. Soc. Exp. BioZ. N . Y . , 1937, 57, 119, 122BROWNLEE : APPROACHES TO THE T.B. PROBLEM. 305duced the mouse test in which an acute infection is established by hugenumbers of tubercle bacilli given intraperitoneally or, more usually, intra-venously.The ultimate assessment may be the mean mortality time ofthe group or the number of organisms recovered from a weighed piece ofspleen, and in general some statistical manipulation is essential for inter-pretation. By exposing groups of mice to a dry mist containing tuberclebacilli, R. E. Glover 113 established a chronic infection restricted to theupper respiratory tract which has proved successful for screening chemo-therapeutic drugs. The guinea-pig test is widely used,”l, ll4, 115 and in theclassical series of researches of Feldman and his colleagues llG has becomea precise tool. It is usual so to design the experiment that a proportionof survivors in a treated group is compared with no survivors in an untreatedgroup.Most workers insist on observing the survivors during the courseof their natural lives. A further refinement is to continue treating a pro-portion of the survivors. The final assessment is preferably in terms of atuberculosis index in which the distribution and microscopic nature of thelesions figure prominently.assembled theexisting knowledge of chemotherapy of tuberculosis and concluded that noknown remedy modified the disease in the experimental animal or man.These authors concluded : ‘’ A specific chemotherapy of tuberculosis hasnot been found and it may be a long time in coming because of the inherentdifficulties of the problem, but it is not a closed chapter.We have somedefinite facts to go on, and some glimpses of light have been seen. Prob-ably some new success with some other bacterial infection will be needed tostimulate a new attack on the more difficult problem offered by tuber-culoses.” G. Domaglr’s 117 very great discovery of the chemotherapeuticactivity of “ prontosil rubrum ” against experimental infections due tovirulent streptococci provided the new impetus. The discovery andevaluation of the chemotherapeutic activity of diaminodiphenyl sulphone,ll*and the demonstration of its high antibacterial activity to tubercle bacilliby N. Rist,llS provided the next step. The chronic toxicity of the parentsubstance (not its insolubility, for toxic blood levels are only too readilyobtained) prompted the preparation of weighted derivatives.Promin(sodium pp‘-diaminodiphenyl sulphone NN’-diglucosesulphonate) gavemore encouraging results in guinea pigs than hitherto observed,120 but clinical113 Brit. J . Exp. Path., 1944, 25, 141.114 M. J. Smith and W. T. McClosky, Publ. Health Repts. Wash., 1945, 60, 1129.115 F. T. Calloman, J. A. Kolmer, A. M. Rule, and A. J. Paul, Proc. SOC. Exp.116 W. H. Feldman and H. C. Hinshsw, Snzer. Rev. Tuberc., 1945, 51, 582.117 Deut. nzed. Woch., 1935, 61, 829.118 G. A. H. Buttle, D. Stephenson, S. Smith, T. Dewing, and G. E. Poster, Lancet,119 Compt. rend. SOC. Biol., 1939, 130, 972.120 W. H. Feldman, H. C. Hinshaw, and H. E. Moses, Proc. Nag0 Clin., 1940,Chemotherapeutic Screening.-In 1932 Wells and LongBiol. N.Y., 1946, 63, 237.1937, i, 1331.15, 695306 BIOCHEMISTRY.studies were disappointing.121? 122 Of a series lZ3, 124 of sulphones testeddisodium formaldehyde sulphoxylate diaminodiphenyl sulphone, d i a ~ o n e , l ~ ~and promizole (p-aminophenyl5-amino-2-thiazolyl sulphone) ,126 were carriedto clinical trial, and the last is still under observation.127 Sulphetrone[a sodium tetrasulphonate of di-(p-3-phenylpropylaminophenyl) sulphone]proved to be comparable in activity to promin in the guinea-pig,12* andremarkably free from chronic Applied to man, it may have ause in certain forms of exudative tuberculosis of the lungs,l30? 131, 132 butits final status is unknown. It is synergic in action with streptomycin,l33combined therapy with which shows promise in miliary tuberculosis andtubercular meningiti~.l3~ Sulphetrone appears to be the most usefulchemotherapeutic agent at present known in the treatment of the allieddisease, leprosy.135The chemotherapeutic sulphones appear to owe their mode of actionto substrate competition, since their activity is inhibited by p-aminobenzoicacid, P.A.B.129 J.Lehmann’s introduction of 4-aminosalicylic acid totuberculosis 136 deserves special attention, since it illustrates the successfuluse of a metabolic approach. Lehmann repeated the observation ofF. Bernheim 13* that benzoates and salicylates increased the oxygen uptakeof tubercle bacilli, and noted that this was a feature of pathogenic strainsonly.On the assumption that benzoates or salicylates might be active asessential metabolites, Lehmann 137 sought for competitive inhibitors. Of50 benzoic acid derivatives examined by microrespiration methods, 4-amino-salicylic acid (paminosalicylic acid, P.A.S.) proved the most effective ininhibiting catabolic oxygen utilisation. The effect was abolished if theamino-group was placed in positions 3 or 5 or if replaced by nitro-. Intro-duction of methyl or stearyl into the 4-amino-group reduced the activityslightly. If the hydroxyl group in the %position was replaced by methyl,activity was retained, but not if it was replaced by amino- or chlorine.Substitutions in the hydroxyl group decreased the activity considerably.Placing the hydroxyl group in position 3 instead of 2 diminished the effect.50, 52.lZ1 H.C. Hinshaw, K. H. Pfuetze, and W. H. Feldman, Amer. Rev. Tuberc., 1944,122 G. Zucker, M. Penner, and H. T. Hyman, ibid., 1942, 46, 277.123 W. H. Feldman and H. C. Hinshaw, Amer. J . Clin. Path., 1943, 13, 144.lz4 M. I. Smith, E. W. Emmant, and B. B. Westfall, J . Pharmacol., 1942, 74, 163.lZ5 F. T. Calloman, Amer. Rev. Tuberc., 1943, 47, 97.lZ6 W. H. Feldman, H. C. Hinshaw, and F. C. Mann, Proc. Mayo Clin., 1944,19, 25.127 H. C. Hinshaw, W. H. Feldman, and K. H. Pfuetze, ibid., p. 25.12* G. Brownlee and C . R. Kennedy, Brit. J . Pharmacol., 1948, 3, 29.129 G. Brownlee, A. F. Green, and M. Woodbino, ibid., p. 15.130 T. Anderson and S. J. Strachan, Lancet, 194-8, ii, 135.131 D.G. Madigan, ibid., p. 174.132 M. G. Clay and A. C. Clay, ibid., p. 180.133 G. Brownlee and C. R. Kennedy, Brit. J . Pharinucol., 1948, 3, 37.134 D. G. Madigan, P. N. Swift, G. Brownlee, and G. P. Wright, Lancet, 1947, ii, 897.135 E. Muir, Trans. Roy. SOC. Trop. Med., 1948, January 15th.Lancet, 1943, i, 14. 13’ lbid., p. 15. 138 J . Bact., 1941, 41, 387BROWNLEE : APPROACHES TO THE T.B. PROBLEM. 307Replacing the carboxyl group by a sulphonic acid group abolished the effect.Substitutions in the carboxyl group (methyl, ethyl, and furfuranylanhydride)changed the activity slightly. Two molecules of 4-aminosalicylic aoidlinked a t position 3 were as effective as 4-aminosalicyclic acid but highlytoxic to animals. G. P. Youmans l39, l40 found P.A.S. to be bacteriostaticand moderately suppressive of experimental tuberculosis in mice.Othershave described the examination of large series of allied compounds withoutuncovering greater activity.lm2 141 The partial reversal of the in vitrobacteriostatic effect of P.A.S. by P.A.B. has been described; l40 anotherauthor found no reversal with P.A.B., but found P.A.S. to resemble P.A.B.in itself inhibiting sulphonamide antibacterial a ~ t i 0 n . l ~ ~ We must guardagainst premature judgment here since it is clear that substances of chemicalpurity have seldom been available, and in the Reporter’s laboratory samplesof commercially available material drawn from two continents have beenfound to contain as little as 30% of 4-aminosalicylic acid.The clinicalstatus of P.A.S. is as yet undefined.In contrast to the minute concentrations of P.A.B. which inhibit sulph-anilyl drugs, an antibacterial action of p-aminobenzoic acid in high concen-tration is now well appreciated,143 and of great interest is a claim that dosesof 0.6 g./kg. gave protection to groups of guinea-pigs against an experi-mentally induced tubercle infe~ti0n.l~~ E. Hoggarth and A. R. Martin 164tested 10 sulphones by a chemotherapeutic antituberculosis test in mice,and concluded that their previous in vitro tests were an unreliable guide.The same appeared to be true of a series of sulphoiiamides 165 which theyalso examined,I n a further trial of drugs prepared primarily as antimalarials, com-pounds related to 2-~-~hloroanilino-4-6-diethylamino-cc-methylbutylamino-6-methylpyrimidine had significant chemotherapeutic effects against tuberclebacilli.166 Of a further 110 related compounds examined by chemothera-peutic tests no compound was uncovered of greater activity, and the authorsnoted the similar requirements for chemotherapeutic activity against themalaria parasite and the tubercle ba~i1lus.l~~Antibiotics.-Streptomycin 144 is the most effective known chemo-therapeutic agent for the control of experimental tuberculosis in the experi-mental animal which infection it will almost completely suppress underfavourable conditions.145 Two biologically active streptomycins have beenisolated from the product of active strains. The substance formerly knownas streptomycin A, which is the major constituent, is properly calledstreptomycin.It is N-methyl-I;-glucosaminidostreptosidostreptidiiie. Thela@ Quart. Bull. N.W. Urziv. Med. Sch., 1946, 20, 420.140 G. W. Raleigh and A. S. Youmans, J. Bact., 1947, 54, 409.141 H. Erlenmeyer, B. Prijs, E. Soskin, andE. Suter, Helv. Chim. Acb, 1948,31, 988.14a E. Diezfalusy, Arkiv Kemi, Min., Geol., 1947, 24, B, No. 1.143 M. Di Fonzo, B’uvrn. Sci., 1947, 2, 287.144 A. Schatz, E. Bugie, and S. A. Waksman, Proc. SOC. Exp. Biol., 1944, 55, 66.146 W. H. Feldman, H. C. Hinshaw, and F. C . M ~ M , Amer. Rev. Tuberc., 1945, 52,269308 BIOCHEMISTRY.minor component is mannosidostreptomycin, formerly called streptomycin B,which is represented as D-mannosido-IY-methyl-L-glucosaminidostreptosido-streptidine; a " streptomycin residue " is also recognised which has anti-biotic and enhancement ~r0perties.l~~ The exact structure of streptomycin(N-methyl-L-glucosaminidostreptosidostreptidine) of molecular formulaC2,H3,012N,, is unknown. Hydrolysis yields biologically inactive strepti-dine, C,H,,04N6, and streptobiosamine, C,,H,,O,N.14'9 148 Streptomycinhas an established place in clinical tuberculosis.NHC( :NH)*NH, I PH\ CH- CH I I 14 NH,*C( :NH)*NH*CH CH*OHCHO-C-OH NHMe-C-€€0- CH H-C-OH\ /CH-OHStreptidine fragmentHO- -H CH3Streptose fragment0 CH&€,*OHN-Methylglucosaminefragmentc I YS treptobiosamine fragmen tSuggested formula for streptomycin.l50 prepared by catalytic reduction of strepto-mycin has significantly less n e u r o t ~ x i c i t y , ~ ~ ~ ~ 152 is equally effective withStreptomycin in experimental tuberculosis,153 is tolerated in patients hyper-sensitive to streptomycin,la and causes neurotoxicity more slowly and withhigher doses than does streptomycin; 155 moreover, it appears equallyeffective in man.154* 155Mode of Action.-The antibacterial action of Streptomycin, but not ofdihydrostreptomycin, is reversed by cysteine, hydroxylamine, and 2-amino-146 S.A. Waksman, Science, 1948, 107, 233.14' E. J. Oswald and J. K. Nielsen, ibid., 1947, 105, 84.148 K. Folkers, N. C. Brink, and F. A. Kuehl, ibid., 1945,102, 500.149 R. L. Peck, C. E. Hoffhine, and K. Folkem, J . Amer. Chem. SOC., 1946,68, 1390.150 J. R. Bartz, J.Controulis, H. M. Crooks, and M. C. Rebstock, ibid., 1946, 68,1 5 1 R. Donovick and G. Rake, J. Bact., 1947, 53, 205.152 A. 0. Edison, B. M. Frost, 0. E. Grwssle, J. E. Hawkins, S . Kuna, C. W. Mushett,15a W. H. Feldman, A. G. Karlson, and H. C. Hinshaw, ibid., p. 494.1 5 4 L. B. Hobson, R. Tompsett, C. Muschenheim, and W. McDermot, ibid., p. 501.1 6 5 H. C. Hinshaw, W. H. Feldman, D. T. Carry and H. A. Brown, i b d . , p. 526.Dihydrostreptomycin3163.R. H. Silbur, and M. Solotorovsky, Amer. Rev. Tuberc., 1948, 58, 487BROWNLEE: APPROACHES TO THE T.B. PROBLEM. 309ethanethiol. Inactivation by cysteine can itself be reversed by iodine inchloroform, a demonstration which proves that thiol groups are notinvolved. Interesting evidence that streptomycin may be involved in anunknown metabolic system arises from experiments on development ofresistance.156 Thus in one population were (a) sensitive, (b) insensitive,and ( c ) dependent organisms.The suggestion is made that streptomycincompetes for the essential metabolite in (a), acts as a growth factor in ( c ) ,and is an essential metabolite synthesised by the organism in (6). Thegrowth-promoting properties of streptomycin on dependent strains isshared by dihydrostreptomycin and by mannosidostreptomycin and itsdihydro-deri~ative.~~~ Urea and its purine and pyrimidine precursors, butnot thiourea, antagonise the in vitro activity against tubercle b a ~ i l 1 i . l ~ ~An interesting reversal of streptomycin activity is that by lipositol, aninositol-galactose complex, found in association with the phosphatidefraction of brain and soya-bean, one part of which reverses 300 parts ofstreptomycin.159Other Chemotherapeutic Antibiotics.-Licheniformin is a polypeptide-containing antibiotic described by Callow et aZ.l60 It has been shown toinhibit the development of experimental tuberculosis in mice.161 Whetherits described nephrotoxicity is intrinsic is a subject of current enquiry.A second chemotherapeutic antibiotic, nisin, appears to have sufficientlylow toxicity and sufficient high therapeutic efficiency against experimentaltuberculosis in guinea-pigs to justify further development. Its chemo-therapeutic activities in other fields appear imposing. 162j 163Cepha,ranthine.-This alkaloid is claimed to be extremely effective inthe treatment of tuberculosis and leprosy in man, for whom it is no moretoxic than quinine.Credited with causing lysis of tubercle bacilli in vitro,it is said to arrest experimental tuberculosis in the guinea-pig.16s* 169 Theeffect on experimental tuberculosis in the guinea-pig has not been con-firmed.170Additional Various Chemotherapeutic Claims.-References have beenfound in the literature to claims for chemotherapeutic activity in the experi-lL6 F. J. Peine and M . Finland, Science, 1948, 107, 143.157 G. Rake, Proc. SOC. Exp. Biol. N.Y., 1948, 67, 249.l 6 8 R. J. Fitzgerald and F. Bernheim, J . Biol. Chem., 1948, 172, 845.159 J. Rymer, G. J. Wallace, L. W. Byers, and H. E. Carter, ibid., 1947, 169, 457.l60 R.K. Callow rand P. D’Arcy Hart, Nature, 1946, 157, 334.161 R. K. Callow, R. E. Glover, P. D. Hart, and G. M. Hills, Brit. J. Exp. Path., 1947,162 A. T. R. Mattick and A. Hirsch, Lancet, 1946, i, 417.163 Idem, ibid., 1947, ii, 8 .164 Brit. J , Pharrnacol. Exp. Med., 1948, 3, 146.165 E. Hoggarth, A. R. Martin, and E. H. P. Young, ibid., p. 153.166 E. Hoggarth and A. R. Martin, ibid., p. 156.167 E. Hoggarth, A. R. Martin, M. F. C. Paige, &I. Scott, and E. Young, ibid., p. 160.168 Nat. Res. Coun. Lit. Survey, U.S.A., 1948.169 J. Buchi, Schweitz. A p o t h J t g . , 1945, 83, 198.170 Report, Int. Red Cross, Geneva, Mkd. et Hyg., 1946, 4, 1 .28, 4183 10 BIOOHEMISTRY .mental animal for the following various substances. The list, from whichclaims for sulphones and sulphoxides have been eliminated, is as follows :sodium t h i ~ s u l p h a t e , ~ ~ ~ a 0.78% aqueous iodine s0lution,~7~ safranine,indamine-blue, tanninheli~trope,~~~, 175 p-ethylaniline, (p-chloroaniline, p -aminophenyl hexyl ether, ethyl p-aminobenzoate, 3 : 4-dichloroaniline,l762 : 5-bis-(p-sulphonamidophenylamino)benzoquinone and its 3 : 6-dichloro-and diacetyl derivatives,17’ phlorogl~cinol,~~~ formic ethyl stearate,ethyl laurate, ethyl myristate, ethyl n-nonanecarboxylate, ethyl arachidate,ethyl palmitate,laO calciferol,lal ascorbic acid,la2 pine oil, la3 ni~otinamide,l*~N1- 3 : 4-dimethylbenzoylsulphanilamide, and thiouracil.l a 5Empirical in vitro Screening.-It is a task of dubious significance toidentify the possible leads indicated by the enormous total of in vitro experi-ments in which acid-fast bacilli and tubercle bacilli of various origin, knownand unknown, have failed to grow in the presence of added substances.No criticism of the many admirable detailed studies of variations of activitywithin a chemical series, as such, should be read into these remarks; how-ever, even here the severe limitations of in vitro comparisons, usually appre-ciated at their source, are often lost to the unsuspecting into whose handsfall the surveys of “antitubercular drugs.” A surveyof the literature since the assessment by Wells and Long can convey buta hint of the field covered, since every student of the subject is aware ofthe existence of a huge total of additional examinations made within com-mercial organisations.The purely negative results are seldom published.The interested reader is referred to C . 0. Guss and M. C. Kloetzel’s up-to-date survey of ‘‘ potential tuberculo-therapeutic compounds.” 16a How-ever, in the following section apparently significant leads derived fromin vitro tests will be discussed.Naphthsquinones, Johne’s Bacillus, and the Tubercle Bacillus.-Threepathogenic organisms, Johne’s bacillus (Mycobacterium paratuberculosis), thetubercle bacillus (Mycobact. tuberculosis var. hominis), and the leprosybacillus (Mycobact. Zeprce), together with the non-pathogenic timothy-grassbacillus Mycobact. phlei, form a closely related acid-fast group.Nor is this all.171 W.H. Feldman, persona1 communication, 1948.172 J. K. Yanagisawa, Jap. J . Exp. Med., 1936, 14, 395.173 E. W. Emmart, Amer. Rev. Tuberc., 1946, 53, 83-96.174 G . Meissner and E. Hesse, Arch. exp. Path. Pharm., 1931, 159, 676.175 E. Hesse, G. Meissner, and G. Quast, ibid., 1928, 135, 82.176 K. I. Melville and R. L. Stehle, Canadian J . Res., 1944, 22, E, 95.177 I. Y. Postovsku and Z. V. Pushkareva, J. Gen. Chem. Russia, 1946, 16, 277.178 Y. Ishmaui, S. Yanagami, and M. Nishigaki, Osaka-yishinshi, 1936, 6, No. 5,Japan; Lit. Tuberk. Forsch., 1936, No. 5, 16.179 R. Hilgermann, Med. Klin., 1939, 35, 739.la0 L. Nigre, A. Berthelot, and J. Bretey, Compt. rend. SOC. Biol., 1936, 208, 1816.lS2 E. Sengir, Ankara Yukalk Zir. ilnstitusa Deig., 1946, 6, 467.la3 E.Daizins, Ann. Inst. Pasteur, 1998, 61, 172.W. Raab, Science, 1946, 103, 670.V. Chorine, Compt. rend. SOC. Biol., 1946, 220, 150.C. J. Duca and M. M. Steinbach, Amer. Rev. Tuberc., 1946, 53, 594BROWNLEE: APPROACHES TO THE T.B. PROBLEM. 31 1I n 1911 F. W. Twort and G. L. Y . Ingrarn lS6, demonstrated, prob-ably for the first time for any micro-organism, a clear growth factorrequirement for Johne’s bacillus.ls63 lS7 The growth factor(s) was suppliedby vaccines of other acid-fast bacteria including Mycobact. tuberculosis var.hominis and Hycobact. phlei, and it was found that lipin solvents couldextract the principle(s). Thirty years later D. W. Woolley and J. R.McCarter found phthiocol (3-hydroxy-Z-methyl- 1 : 4-naphthaquinone)isolated from tubercle bacilli,189 and synthetic 2-methyl- 1 : 4-naphtha-quinone, a biologically active vitamin-K analogue, markedly to increasegrowth of Johne’s bacillus on synthetic medium, but to be inferior to con-centrates extracted from phlei cells, so that it was clear that the phleiconcentrates contained additional growth substances. More recently,growth-stimulating substances, whose effect could not be duplicated byvitamin K or its analogues, have been identified in bovine tuberculin,that is, the soluble products of the metabolism of the organism.lgO Thisproject is being furthered at several centres.*B.C. J. G. Knight lgl has recently collected the evidence for thoseorganisms which synthesise vitamin-K-active substances and notes ourignorance of whether adapted lg2 Johne’s ba.cillus strains synthesise thesesubstances.The importance of these observations lies in the demonstrationof a vitamin-K-active substance as a product of bacterial synthesis. Thus,on the one hand is the demonstration of a vitamin-I<-active substanceproduced by bacterial synthesis and on the other of a growth factor forJohne’s bacillus. Is this adequate evidence that naphthaquinones haveimportant metabolic functions in Johnes’s bacillus, and in acid-fast organismsin particular? That this may be so derives support lgl from the demon-stration by McIlwain that iodinin, a purple dye from Chromobacteriumiodinum, inhibits the growth of a number of bacteria including streptococciand the tubercle bacillus.193 It was further shown that 1 : 4-, 1 : 5 - , andlS6 Proc.Roy. SOC., 1911, 84, By 517.lS7 “ A Monograph on Johne’s Disease,” BalIiAre, Tindall and Cox, London, 1913.lS8 Proc. SOC. Exp. Biol. N.Y., 1940, 45, 357.189 M. S. Newman, J. A. Crowder, and R. J. Anderson, J . Biol. Chem., 1934,105, 279.lS0 J. Glavind and H. Dam, Physiol. Plantarum, 1948, 1, 1.191 “ Growth Factors in Microbiology. Vitamins and Hormones. 111.” AcademicPress, New York, 1945.G. W. Dunkin, J . Comp. Path., 1933, 46, 159.193 H. McIlwain, Biochem. J., 1943, 37, 265.* Added in Proof.-There has been a tendency to relate Woolley and McCarter’sobservationslS8 to the emergence of adapted strains since few workers have been able toduplicate the results. J. Francis, J. Madinaveitia, H.M. MacTurk, and G. A. Snow(Nature, 1949, 163, 365) failed to detect free phthiocol in fresh extracts of Mycobacteriumtucerculosis but isolated a new vitamin-K-like yellow oil of molecular weight greaterthan that of vitamin K,. Neither theoil nor phthiocol was a growth-factor for Johne’s bacillus.The latter authors report the isolation, from Mycobact. phlei, of a growth-factor forJohne’s bacillus obtained crystalline as a colourless aluminium derivative of approximateformula, C49HS6010NBA1 ; it is apparently not a naphthaquinone.This oil gave phthiocol on alkaline hydrolysis312 BIOCHEMISTRY.1 : 8-dihydroxyanthraquinones and 2-methyl-1 : 4-naphthaquinone wereactive in reversing the inhibitory action of iodinin.A number of authors have found inhibitors modelled on vitamin-K-active naphthaquinones to inhibit the growth of tubercle bacilli in the testtube,194, lo5> lS6 but these and similar analogues have proved inactive inthe experimental animal.lS4 Whether the normal vitamin-K concentrationof the experimental animal (guinea-pig) is too high to allow the maintenanceof a ratio of the antibacterial substance to its inhibitors (vitamin K) orwhether the bacteriostatic substance is degraded in the body has not beenproved. The former possibility is of special interest since it will be recalledthat pantoyltaurine, the sulphonic acid analogue of pantothenic acid, canretain its bacteriostatic activity in vivo and thus behave as a chemothera-peutic agent in one animal but not in the other.The normal pantothenateconcentration in the blood of mice is higher than in rats, so that a chemo-therapeutic ratio of pantoyltaurine : pantothenate could be maintained inthe latter but not in the former.lg7 V. C. Barry, J. G. Belton, M. L. Conalty,and D. TwomeymO found the dark red base, C24HI8N4 (I), produced byoxidation and condensation from 2-aminodiphenylamine to be powerfullyantiseptic in the case of the tubercle bacillus. Its high toxicity precluded0 m+ 0 (11.)H(111. )its use for animal protection experiments. The chemical relation to iodinin(11) is of interest. Whether the specific in vitro activity of the diphenyl-amine-2-carboxylic acid derivatives (111) recently described are also relatedto naphthaquinone metabolism has not been shown.201A naturally occurring quinone of similar structure to iodinin is usnicacid.Of potent activity in vitro against the tubercle b a c i l l u ~ , ~ ~ ~ ~ log itdoes not appear to have been tested in the animal.lB4 W. Alcalay, Schweix. 2. Path., 1947, 10, 229.lB6 C. N. Iland, Nature, 1948, 161, 1010.lB6 A. Gronwall and B. Zetterberg, U p a h La.kareforen Forh., 1947, 52, 199.lQ7 H. McIlwain and F. Hawkins, Lancet, 1943, i, 449.lB8 V. C. Barry, L. O’Rourke, and D. Twomey, Nature, 1947,160, 800.lQ9 F. Bustinza and A. C. Lopez, “Antibiotics from Lichens,” An. Jardin BotMadrid, 1946, 7, 1-38BROWNLEE : APPROACHES TO THE T.B. PROBLEM. 313Inositol, Streptomycin, and Lipositol.-Inositol occurs naturally in highconcentration in brain and heart muscle of higher animals ; it is an essentialgrowth factor for a fungus, Nematospora gossypii,202 a metabolite associatedwith bios I of yeasts,203 and a nutritional factor associated with alopeciain a strain of mice,,04 but it is not a t present known as a nutritional require-ment for any bacteria.lgl A diverse range of bacteria synthesise inositol,including some associated with intestinal biosynthe~is,~~~ as do also acid-fast organisms like the tubercle bacillus of human, bovine, and avian origin,the timothy-grass bacillus, and the leprosy bacillus (Table 11).An interest-ing difference is seen between the inositol content of Gram-negative (and? Gram-positive) organisms which contain from 0.09 to 0.17% and thetubercle bacillus which synthesises from 3 to 9% of inositol. Andersonand his colleagues3 found inositol among the cleavage products of thephosphatides in which it fulfilled the function of the nitrogen-containingcomplexes of the more usual phosphatides of higher plants and animals.By alkaline saponification of the phosphatide he isolated “ maninositose ” ofwhich the cleavage products were mannose and inositol. A reference tothe known cleavage products of streptomycin discussed earlier in this Reportshows that streptidine may be regarded as a substituted inositol linked, itis thought, through an ether linkage to a novel sugar. A third interestingfinding, which appears to relate the three observations, is the demonstrationthat lipositol from brain and soya bean competitively inhibits the anti-bacterial Gram-negative action of streptomycin. Lipositol from soya beanwa.s so active that one part inhibited 300 parts of streptomycin. In 1942J. Folch and D. W. Woolley ,05 showed brain phosphatide to contain inositol,and subsequently the inositol-containing component to which the namelipositol was given was found to have an inositol-galactose ( 2) structure.2*6Enquiry directed to the isolation from virulent tubercle bacilli of inositol-containing substances with a view to a comparison of their capacity toinhibit streptomycin, when compared with lipositol, would be valuable.It would also be of interest to relate strains of tubercle bacilli sensitive orresistant to, and dependent on, streptomycin to their (inositol-containing)inhibitory substances. Meantime the direct empiric lead might be followed.Calciferol and Lupus.-It was first observed clinically that cutaneoustuberculosis responded to the oral administration of calciferol (vitaminD,) .,073 20* A suppressive effect upon experimental tuberculosis in guinea-pigs is claimed 209 with an additional observation that “ inactivated ”ergosterol, in larger doses, gave a superior effect. It is clearly desirable to201 A. A. Goldberg, H. S. Jefferies, and H. S . Turner, Quart. J . Pharrn., 1948, 21, 10.202 H. W. Buston and B. N. Pramanik, Biochem. J., 1931,25, 1656, 1671.203 E. V. Emtcott, J . Physiol., 1928, 32, 1094.204 D. W. Woolley, J . Biol. Chem., 1941, 139, 29.305 Ibid., 1942, 142, 963.2O7 G. B. Dowling and E. W. P. Thomas, Proc. Roy. Xoc. Med., 1945, 39, 96.2oE A. Charpy, Ann. Dermat. Prunce, July, 1945.*Ob W. Raab, Science, 1947, 106, 646.Nature, 1948, 162, 622.206 D. W. Woolley, ibid., 1943, 147, 481314 BIOCHEMISTRY.attempt to identify the active substance in man and in the animal, and astudy of excretory products might be expected to throw light on the problem.In another connection it has been found that feeding the allied moleculecholesterol to rats resulted in the excretion of fatty acids of molecularformula C25H5002,210 and Sir Robert Robinson has indicated the possibleroute of degradation which would involve unwinding the tetracyclic nucleusof the steroid by breaks at the point where the rings are fused, and alsoat some peripheral point, and in the side chain, and he also indicated apossible degradation to 5 : 18-dimethyltricosanoic acid. Should the acidobtained by feeding cholesterol prove to be a branched-chain acid, thedetermination of its structure is a matter of some urgency, and a com-parison with the excretory products derived from feeding calciferol and“ inactivated ” ergosterol most desirable.Leprosy and Chaulmoogra.-The hint supplied by the traditional use ofchaulmoogra oil in leprosy in the East was followed up by Power and hiscolleagues 216* 217 and culminated in t h e elucidation of the structure of chaul-moogric and hydrocarpic acids.211* 216* 217CHz-CH2\CH*[ CH2],*C0,HhH=CH/(Chaulmoogric acid, n = 12. Hydnocarpic acid, n = 10.)A large number of di-substituted acetic acids were synthesised andtested in vitro. w-cycZoHexy1-substituted aliphatic acids had maximum invitro activity with 14-17 carbon atoms, and activity was greatest whenthe carboxyl group was in the centre of the chain. A further series ofdialkylacetic acids without a ring structure was also studied. These activelong-chain acids were too irritant to test on experimental animals.211Starting from roccellic acid (a-methyl-a’-n-dodecylsuccinic acid) Barryand his colleagues 212 similarly encountered maximum in vitro activityagainst tubercle bacilli, at a chain-length of 13-15 carbon atoms. Ahalf-ester of ad-di-n-heptylsuccinic acid, differing from heptyloctylaceticacid only in the possession of an extra carbethoxy-group, was found to be10 times as active in vitro. These compounds were inhibited by serum anddisplayed little in vivo activity, but may prove of value when used bylocal application.213 There has been an unconfirmed claim that the ethylesters of chaulmoogric acids are synergic with streptomycin and may havea use in renal tuberculosis.214 Streptomycin appears to have little clinicalcurative effect in leprosy.2ls2lO R. P. Cook, N. Polgar, and R. 0. Thompson, Biochem. J., 1948, 43, ix.211 W. M. Stanley, G. H. Coleman, C. M. Greer, J. Sack& and R. Adams, J . Phar-el2 V. C. Barry, Nature, 1946, 158, 863.215 V. C. Bmy, personal communication, 1948.214 G. E. Slotkin and 8. Wilber, Int. J . Leprosy, 1948, 16, 273.el6 G. H. Faget and P. T. Erickson, J . Arner. Med. ASSOC., 1948. 186 451.216 F. B. Power and F. H. Gornall, J., 1904, 85, 861.217 M. Barrowcliff and 5’. B. Power, J . , 1907, 91, 567.macol., 1932, 46, 121BROWNLEE: APPROACHES TO THE T.B. PROBLEM. 315Epilogue." ' It is a poor sort of memory that only works backwards,' the Queenremarked. "-Lewis Carroll.The discussion of material presented in this Report derives its impetusfrom knowledge about the chemical attack upon the tubercle bacillus securedmainly during the last ten years. The chemotherapeutic success in thefield of allied bacterial disease which Wells and Long prophetically expectedto stimulate the more difficult attack on the tubercle bacillus has provedeffective. We may confidently expect inore effective antibiotic agents tobe discovered, and more effective chemotherapeutic agents to be synthesised ;in objective the empirical approach has become routine : only the methodsdiffer.The object of the direct approach to the chemotherapy of tuberculosismay be simply stated as '' the elimination of the parasite." We have toconsider the possibility that this simplication may falsify the clinical status,by reason of the morbid anatomy of the disease to which attention hasbeen drawn. A second weighty consideration is the slow metabolisni ofthe causal parasite which endows it with a marked capacity to surviveunfavourable environments. Emphasis has been placed, therefore, uponthose pathological characteristics which make tuberculosis a special problem.The indirect approaches which have been indicated derive their sourcesfrom the purposeful studies of the biochemical lesions caused by the chemicalcomponents of the organism, lipins, carbohydrates, and proteins. In thisconnection the ingenuity of the organic chemist can be exploited toprepare synthetic, physiologically active analogues of the causal agents,to model related physiologically " blocking " structures to them, and tocouple these new presumed haptens with known antigenic proteins. Em-phasis must also be placed on discovering the physiological functions ofthe presumed essential metabolites. The protein component( s) does notappear to have attracted the attention it may deserve, since the evidenceappears complete that this substance is directly responsible for a host-parasite collaboration which results in hypersensitisation and death of thehost's tissue cells. A chemical attack related, for the purpose of illustrationonly, to the toxin-antitoxin mechanisms appears worthy of chemicalattention.But these are words, and a poor substitute for experimental evidence.G. B.R. BENTLEY.G. BROWNLEE.A. J. P. MARTIN.C. RIMINQTON.F. SANGER

ISSN:0365-6217    

DOI:10.1039/AR9484500238

出版商:RSC    

年代:1948

数据来源: RSC

摘要:

ANALYTICAL CHEMISTRY.1. INTRODUCTION.THE demand for increased production of goods and materials-and forincreased rate of production-created by war-time exigencies and intensifiedby post-war plans for economic recovery have done much to accelerate thenatural development of analytical methods that are both rapid and accurate,yet suitable for routine measurements by semi-skilled or hastily trainedoperatives. Nowhere does this appear so clearly as in the field of emissionspectrography where a remarkable degree of inechanisation has alreadybeen achieved. The special interests of soil-scientists and biochemists havelikewise speeded the developments of the Lundegkrdh technique fore-shadowed in the Report for 1941 and now described in the section of flamephotometry.Yet despite the ever-increasing importance of physical methods, morethan half the papers published annually still relate to the procedures ofvolumetric analysis, and although there have been no spectacular develop-ments the past decade has seen steady progress in its techniques andapplications, some of which are reviewed in Section 4 of this Report.Thelast section deals with a complex naturally occurring material of greateconomic importance-sen water-which presents many absorbing anddifficult problems tlo the analyst. H. I.2. ANALYTICAL EMISSION SPECTROGRAPHY.The value of emission spectrography as an analytical technique wasthoroughly established when the subject was last reviewed 1 but its studyreceived a major impetus a t the outbreak of war in 1939, when industrywas faced with rapid expansion.I n the metallurgical industries, andparticularly in those concerned with light a.lloys, the provision of increasedanalytical facilities presented serious difficulties since the additional skilledstaff and buildings needed for chemical methods of analysis were rarelyavailable. The problem was happily solved by the installation of spectro-graphic equipment which provided analyses of a satisfactory degree ofaccuracy in a fraction of the time taken by the chemical methods then inuse, whilst it was economical in both laboratory space, and numbers andquality of personnel.The process employed in quantitative analytical spectrography is treateda t length in the standard textbooks and various specific techniques have1 Ann.Reports, 1937, 34, 454.2 W. R. Brode, “ Chemical Spect,roscopy,” John Wiley & SQns Inc., New York,and Chapman and Hall Ltd., London ; F. Twyman, “ The Spectrochemical Analysisof Metals and Alloys,” Charles Griffin & Co. Ltd., London; D. M. Smith, “ CollectedPapers on Metallurgical Analysis by the Spectrograph,” The British Non-FerrousMetals Research Association, London; “ Analysis of Aluminium and its Alloys :Spectrographic and Polarographic Analysis,” The British Aluminium Co. Ltd.From that time progress has been continuousULAYTON : ANALYTICAL EMISSION SPECTROCRAPHY. 317been described in the literature.3 When spectrography is used as ananalytical tool in industry the details of the method employed dependlargely on the nature of the material to be analysed, the speed and accuracyrequired, and the equipment available, but the following steps a, re commonto most procedures.The material is first sampled, either by taking it intosolution in a suitable solvent, by pelleting, or by casting it into the formof rods or discs which can form one or both of the electrodes of the excitationdischarge. After being sampled, the material is suitably excited, thespectrum is recorded photographically and the densities of the spectrumline images are measured by ineans of il microphotometer. Subsequentcalculations allow the concentrations of the constituents of the sample tobe deduced from these density measurements.Errors in the conventional method of quantitativc analysis may arisca t all stage^.^ Pnefficient sampling is an obvious source of inaccuracy butone that can be readily minimised.The numerous errors associated withthe excitation of the spectrum and the use of the photographic plate areless obvious and are more difficult to overcome.It is generally accepted that attempts to accelerate the spectrographicprocess by shortening the exposure time and by using fast photographicemulsions may have a deleterious effect on the overall accuracy of theanalysis, and it is better to increase the accuracy of the method and togain speed by reducing the iiuniber of replicate analyses carried out oneach sample.The accuracy of analysis has been the subject of considerable attention,Gand after an improvement brought about by a proper understanding ofthe photographic process and the requirements of accurate photometry,attention was directed- a t improving the spark source normally employedfor the routine analysis of metallic materials.Several types of improvedexcitation unit have been described, and their use may, in general, besaid to result in an improvement in analytical accuracy of some 50% whenthey are applied to light alloys ; with ferrous materials the improvementS. Levy, J . AppL Physics, 1940, 11, 480; J. van Calker, Spectrochim. Acta, 1944,2, 333; P. Cohen, J . Opt. SOC. Amer., 1946, 36, 489; A. Walsh, ‘‘ Collected Papers onMetallurgical Analysis by the Spectrograph ” (see ref. Z), p. 65 ; A. Cornu, Compt. rend.,1946,222, 1341 ; J.Wilken, Metallwirts., 1940,19, 121 ; A. von Zeerleder and F. Rohner,Helv. Chim. Acta, 1940, 23, 1287; H. Correll, Aluminium, 1940, 22, 525; R. W. Callonand J. E. Burgener, J . Opt. Soc. Amer., 1944, 34, 543; H. L. Collins and R. T.V. Callon,Canad. Metals, 1945, 8, 20; G. S. Smith, Met. I d . , 1945, 67, 226; 1947, 70, 23;“ Reports of A.S.T.M. Committee E-2 on Spectrographic Analysis,” Proc. Amer. SOC.Test. Mat., 1939 onwards.T. A. Wright, Amer. SOC. Test. Mat., Reprint No. 112,1940; H. Mader and R. Poet-zelberger, Metallwirts., 1940, 19, 381; N. V. Buyanov, Zavod. Lab., 1940, 9, 69;V. K. Prokof’ev, Izvest. Akad. Nauk, S.S.S.R., 1940, (Phys.), 4, 5 ; A. G. Quarrell andG. E. A. Bramley, J . Inst. Metals, 1941, 07, 25; W. Seith and H.Hessling, Z. Elektro-chem., 1943,49, (4/5), 210; S. Levy and 0. W. Christine, J . Opt. SOC. Amer., 1946,36,503.ti H. Miider and R. Poetzelberger, Spectrochim. Acta, 1039, 1, 213.6 A. E. Ruehle, Bull. Amer. SOC. Test. Mat., 1941, 33; H. B. Vincent and R. A.Sawyer, J . Opt. Soc. Anter., 1942, 32, 686318 ANALYTIOAL CHEMISTRY.is less marked but is still appreciable. Microphotometry of the photo-graphic negative, the introduction of which had enabled consistently satis-factory analyses to be carried out by relatively unskilled operators, involvesminor but appreciable errors. Recent developments aim to supplant itby the direct photoelectric measurement of the spectrum line intensities.The speed of analysis has continuously increased, and it is common-place to find methods using photography of the spectrum and subsequentmicrophotometry of the line images which take no more than 10-15minutes for a complete analysis of a sample for several elements, whilst ifa direct photoelectric measurement of line intensity is made the time maybe no more than 2 minutes.The spectrograph has also been applied to an ever-increasing range ofanalyses outside the metallurgical field and is now widely used in suchdiverse work as the analysis of biological materials, ores, and oil additives.Progress in the paat ten years may thus be summed up as an increasein the accuracy, speed, and scopc of the method.The more recent develop-ments in source units coupled with the application of multiplier photocellsto the direct measurement of spectrum line intensities show promise ofproducing still greater accuracy and speed in the near future,Personal ErPors.-The spectrographic process involves numerous steps,and many of them are liable to introduce errors when they are carried outby inexperienced workers. Attention has therefore been directed at simpli-fying and mechanising the process so that it is as independent as possibleof the mistakes and judgment of the operator.In preparing the electrodes for excitation, manual filing has been largelyreplaced by machining or grinding, and the machines designed for thisoperation provide an electrode tip of standardised shape and finish.' Im-proved electrode stands have been described and in the type due toA. von Zeerleder and F.Rohner three pairs of electrodes are accommodated ;the first pair is automatically pre-burned for a given period, the secondprovides the spectrum lines in analysis, and the third can be simultaneouslychanged for a further pair of fresh electrodes. The photographic exposurehas been controlled by the use of automatic timing switches which give anexposure of predetermined duration lo or by photoelectric devices whichexpose the photographic emulsion until a fixed amount of light energy hasbeen emitted by the discharge.ll Automatic photographic processing as7 C. L. Waring, Metals and Alloye, 1945, 21, 1013; H. Moritz, Aluminium, 1940,22, 421 ; H. Kaiser, Spectrochim. Acta, 1942,2, 288; E. J. Esstmond, J. Opt. SOC. Amer.,1944, 34, 621 ; K.R. Mayors and T. H. Hopher, Ind. Eng. Chem. Anal., 1941, 13, 647.8 H. R. Clayljon, J . Sci. Irsek., 1941,18, 65 ; B. F. Scribner and C. M. Carless, J . Res.Nut. Bur. Stand., 1943, 30, 41; J . Opt. SOC. Arner., 1943, 53, 515; W. D. Owsley endR. C. McReynolds, Rev. Sci. Ins&., 1942, 13, 342.Specdrochdm. Acta, 1940, 1, 400.10 G. Belz and G. Reiniger, &id., p. 323 ; F. Walbank, ibid., 1941, R, 160; R. H. Keck,11 J. S. Sedov, Cmpt. rend. (Doklady) Acad. Xci. U.S.S.R., 1943, 41, 329; H. R.ibid., 1944, 2, 389.Clayton, J. Sci. I w t r . , 1940, 23, 233ULAYTON : ANALYTIOAL EMISSION SPECTROBRAPHY. 319used for large-scale roll-film development has not been applied to spectro-graphy, but commercial equipment of a semi-automatic nature for dovelop-ing, fixing, washing, and drying is available.la Many types of microphoto-meter have been devisedJ13 ranging from models designed for very rapidworking l4 to those which are prepared to sacrifice speed to the attainmentof a higher accuracy.l5 In this country the Hilger non-recording micro-photometer is almost universally employed , partly for preference andpartly because it is the only suitable instrument manufactured here.Itis a basically simple apparatus requiring little or no maintenance and isconvenient to use, but it is considered by some users to compare unfavour-ably with representative Continental and American instruments becauseof the slow speed of response of its galvanometer and its critically focussedoptical system.The calculation of the analytical results from the microphotoinetricmeasurements has been accelerated and simplified by the use of calculatorswhich convert the readings of the microphotometer galvanometer intorelative light intensity values and subsequent,ly concentrations of thevarious minor constituents.16 These instruments have become almost anecessity in those laboratories where large numbers of determinations aremade and various patterns have been described. Three interesting detaileddescriptions of accessory equipment of the type mentioned above havebeen published by H.Brackebusch,l7 J. L. Saunderson and V. J. Calde-~ o u r t , ~ * and H. M ~ r i t z . ~ ~Sampling.-To avoid heterogeneity in the sample, many workers havebeen attracted by methods of analysis involving the use of a solution ofthe material under test.20 This procedure has several advantages ; non-metallic and non-conducting materials can be satisfactorily dealt with, andl2 See, e.g., trade literature of Associated Research Laboratories, Glendale, Cali-fornia.l3 R.C. Machler, Proc. 7th Summer Conf. on Spec. and its Applications, Mass.Inst. Toch., 1939, 1940, 65; E. M. Thorndike, Ind. Eng. Chem. Anal., 1941, 13, 66;A. Gatterer, Spectrochim. Acta, 1941, 1, 352 ; H. B. Vincent and R. A. Sawyer, J. Opt.SOC. Amer., 1941, 31, 639; W. S. Baird, ibid., p. 179; H. W. Diotert and J. Schuch,ibid., p. 54 ; R. Poetzelberger, Spectrochim. Acta, 1943, 2, 296.l.1 W. A. Kerr, Proc. 7th Summer Conf. on Spec. and its Applications, Mass.Inst.Tech., 1939-1940, 68; R. Fiirth, Nature, 1942, 149, 7 3 ; E. M. Thorndike, I d . Enq.Chem. Anal., 1941, 13, 66-67.l6 G. 0. Langstroth, K. B. Newbound, and W. W. Brown, C a d . J . Res., 1941,A , 19, 103.l6 G. Balz, Aluwziniurn, 1940, 22, 343; C. King, J. Opt. SOC. Amer., 1942, 32, 112;N. S. Bmmmelle and H. R. Clayton, J. Xoc. Chem. Id., 1944, 63, 83; D. A. Sinolair,J. Opt. SOC. Amer., 1944, 34, 689; A. P. Vanselow and G. F. Liebig, ibid., p. 219;J. C. Henderson-Hamilton and A. Lourie, J. SOC. Chem. Ind., 1945, 64, 309.l7 Spectrochim. Acta, 1941, 8, 18.Aluminium, 1942, 24, 394.2o R. Bauer, ibid., 1940, 82, 9 ; W. D. Treadwell and R, Walti, Helv. Chim. Acta,1940, 23, 1446; A. Beerwald and W. Brauer, 2. Metallk,, 1941, 33, 44; R.Walti,Diss. Eidg. Tech. Hoohsch., Zurioh, 1943; R. J. Kiers w d D. T. Englis, I d . Eng.Ghem. And., 1940,12, 275,J . Opt. SOC. Amer., 1944, 34, 116320 ANALYTICAL CHEMISTRY.the preparation of standards of comparison is greatly facilitated since theymay be synthesised from pure salts. Excitation may be by arc, by spark,or by a controlled flame. In use, solution methods are generally moretime-consuming than those employing solid electrodes of the material tobe analysed, and if the solution is used as such, without evaporation, thespray from the discharge may damage other apparatus in the laboratory.Pelleting or briquetting of metallic filings 21 or non-metallic powders 22 hasbeen used to minimise the heterogeneity of the sample but the techniqueis not widespread.The most generally accepted procedure for the analysisof metals is to employ electrodes of the material under test, and in thefield of metallurgical analysis these are usually prepared by casting in oneor two forms. If the samples are cast as rods23 the discharge may bepassed between two of them; if they are cast in disc form the discharge ismade to take place between the surface of the disc and a counter electrodeof another material, usually a pointed rod of graphite.24 In using elec-trodes of these types attention must be paid to the casting technique.25The moulds employed are generally designed to give rapid chilling in orderthat the grain size of the metal comprising the sample shall be as fine aspossible. The temperature of both the mould and the metal before samplingis usually well defined.Such measures ensure a consistently high standardof sampling, but in order to reduce further the effects of heterogeneity inthe sample itself it is customary to make replicate photographic records ofthe spectrum of each sample, a different part of the sample being used foreach exposure.26 Rotating electrodes and discs have been tested tominimise sampling errors but are not generally accepted. as necessary.Calibration and Photographic Procedures.-For many years quantitativeanalysis was carried out almost exclusively by B. A. Lomakin’s method,27in which the photographic plate is calibrated by the inclusion of spectra ofstandard alloys of which the composition has been determined by carefulchemical analysis.This procedure suffers from two disadvantages : it iswasteful, since much of the space on the photographic plate is taken up bythe spectra of the standard alloys, and the casting and analysis of thelarge numbers of these standards which are required for a full and usefulapplication of the method are laborious tasks. Other methods of platecalibration have therefore been developed.In geceral, tzhese methods iiivolve the inclusion on each photographicplate of an intensity pattern consisting of steps of known relative intensities,fcrined, for example, by exposing a portion of the plate to a light source21 H. C. Harrison and C. C. Ralph, Ind. Eng. Chem. Anal., 1943, 15, 466; C. J.Neuhaus, J . Opt. SOC. Amer., 1943, 33, 167; P.A. Leichtle, ibid., 1944, 34, 454; H. W.Dietert, ibid., 1941, 31, 693.2% E. J. Fitz and W. M. Murray, Id. Eng. Chem. Anal., 1945,17, 145; S. H. Wilsonand M. Fieldes, New Zealand J. Sci. Techn., 1941, 23, 47B.H. Moritz, Aluminium, 1940,22,421; 1943,25, 389.24 H. V. Churchill and J. R. Churchill, J . Opt. SOC. Arner., 1941,31, 611.25 “ Analysis of Aluminium, etc.” (see ref. 2), 2nd edn., p. 16.Ibid., p. 19. 27 2. U W Q . ohem., 1930, 187, 76CLAYTON : ANALYTICAL EMISSION SPECTROQRAPHY. 32 1through a, stepped optical wedge or rotating stepped sector. After measure-ment of the density of the photographic images of the steps, the character-istic curve of the photographic plate may be constructed, an artificial originbeing employed because the absolute intensity of the calibrating intensitypattern is unknown.From this curve the intensity ratio of any spectrumline pair may be determined from the difference in densities of the twolines, and since the intensity ratio is a function of the concentration of theminor constituent, the amount of minor constituent present may be deter-mined. Preliminary work is involved in finding the relationship betweenthe intensity ratio of the two spectrum lines and the concentration of theminor constituent, but this is easily and accurately done by using analysedstandards.A method of plate calibration of this type is now commonly employedin laboratories dealing with large numbers of similar samples, but where avariety of materials are analysed the method is not so useful because ofthe large amount of preliminary calibration required.A proper under-standing of the photographic process, as it affects photometric photometry,is essential for the successful application of plate calibration techniquesto spectrography and the subject has been fully discussed by E. H. Amstein.28The photographic emulsion even on a single plate does not necessarily behaveas if it were uniform in its reaction to light, whilst the image after develop-ment often lacks uniformity through an incorrect processing techniquewhich must be carefully established and standardised. The characteristicsof photographic emulsions to ultra-violet radiation have been determined 29and by reference to these data workers have been able to select the mostsuitable type of plate and spectrum lines for their particular needs.Correction for spectrum ‘‘ background ” has been considered from aphotographic aspect and is usually allowed for in trace analysis,30 but itseffect is inappreciable in the analyses of constituents present in higherconcentrations.Excitation Sor~~es.-Probably the most outstanding contribution toimproving the speed and accuracy of the spectrographic process during thepast ten years has been the development of improved excitation units toreplace the D.C.arc and the condensed spark units previously employed.The condensed spark is not an ideal source for spectral excitation, par-ticularly for those metals whose oxides are good insulators, since the amountof energy passing through the analytical gap a t each individual spark isdetermined by the voltage a t which the gap breaks down.This breakdownvoltage may vary between wide limits depending on the condition of theelectrode tips and the degree of ionisation of the vapour between them a tthe instant when the discharge starts. With gap conditions which do not28 J . SOC. Chem. Ind., 1943, 62, 51; A. C. Coa,tes and E. H. Amstein, ibid., 1942,61, 21.E. H. Amstein, ibid., 1944, 03, 172.30 L. W. Strock, J . Opt. SOC. Amer., 1942, 32, 103; R. 0. Scott, J. SOC. Cheni. Ind.,1944,63, 26; J. Cholak and R. V. Story, J . Opt. SOC. Amer., 1941, 51, 730.REP.-VOL. XLV. 322 ANALYTICAL CHEMISTRY.provide a constant breakdown value, therefore, the discharge is not repro-ducible.In order to stabilise the breakdown potential it is common practiceto irradiate the gap with ultra-violet radiation of short wave-length, or toprovide a " leading point " across the spark gap to produce a corona dis-charge before the passage of the spark.31 These methods are not entirelysatisfactory and other methods of controlling the discharge have beeninvestigated.The first controlled condensed spark was described by 0. FeussnerF2who employed a synchronous rotary spark gap to apply the discharge voltageto the gap at predetermined intervals. More recently, J. T. M. Malpicaand T. M. Berry 33 have developed an electronically-controlled condensedspark in which the control is on the primary side of the high-voltage trans-former. In order to define the discharge conditions more accurately, otherworkers have attempted to separate the high-current-density spark phaseassociated with the initial breakdown of the gap from a subsequent low-current-density arc phase which provides most of the light output fromthe discharge, but itself plays no part in gap breakdown.The first circuitof this type was developed by K. Pfeil~ticker,~~ and subsequently, improvedsources working on the same basic principles have been described by otherworkers. Each of these sources has its own particular merits and dis-advantages; for instance, that due to A. Walsh 35 is so designed that it iseasily constructed from readily available components, and several circuitsto this design are in operation in this country with satisfactory results.The source unit described by C.Braudo and H. R. ClaytonY36 and producedin this country by the Metropolitan Vickers Electrical Co. Ltd., is morecomplicated, but dispenses with auxiliary spark gaps or synchronous inter-rupters by adopting electronic methods of synchronising. The " Multi-source " of M. F. Hasler and H. W. Dietert 37 and the circuit due toV. J. Caldecourt and J. L. Saunderson38 are commercially available inAmerica, where their versatility and stability have proved to be of greatvalue in analytical work.In the composite discharge units mentioned above, the analytical gapis first bridged by a very high-voltage discharge of low power and shortduration. The voltage is applied to the analytical gap a t a predeterminedtime and its value is so high that breakdown of the gap occurs practicallyinstantaneously irrespective of the condition of the electrode tips or ofthe state of the vapour between them.Once the gap has been bridged, asecondary discharge at a comparatively low voltage (250-2000 v.) isallowed to cross it, and the main spectral emission is due to this discharge.Conditions in this low-voltage discharge circuit may be modified by alter-31 @. Balz, H. Kaiser, and P. H. Keck, Spectrochim. Acta, 1941, 2, 92; G. Balz,Aluminium, 1944, 26, 60.33 2. techn. Physik, 1932, 15, 673; 2. Metallk., 1933, 26, 73.33 Gen. Elec. Rev., 1940, 43, 333.34 2. Electrochem., 1937, 43, 719; 1938, 30, 211 ; 1941, 33, 267.35 Met.Id., 68, 243, 263, 295,37 J . Opt. SOC. At)26T., 1983, 83, 218.36 J . Xoc. Chem. Id., 1947, $8, 259.a6 Ibid., 1946, 36, 90CLAYTON : ANALYTICAL EMISSION SPECTROGRAPHY. 323ation of the electrical parameters to produce any type of excitation rangingfrom a high-current, short duration spark to an arc of long duration. Theexcitation conditions can thus be adjusted to suit any particular problem.Minor constituents present in concentrations up to some 5% can beeffectively dealt with by these source units and an accuracy of some 24%of the amount of minor impurity present is generally attainable on singleanalyses. This performance is a marked advance in light alloy analysis,but does not show a great improvement over the performance of the con-densed spark for steel analysis.Coupled with the versatility of the units,however, the increase in accuracy is a very valuable attribute.Direct Measurement of Spectrum Line Intensities.-The conditions inthe electrical discharge having been stabilised, attention was directed toeliminating the photographic plate and its subsequent microphotometry.During recent years the measurement of the low light intensities encoun-tered in emission spectrography has been made practicable by the develop-ment of stable photo-electron multipliers.39 Interest in this field has beenlargely centred on the electrostatically focussed multiplier photocells origin-ally developed in America and now manufactured in this country. Thecharacteristics of these cells are described in the makers’ literature 4o andhave also been studied in detail by K.G. Kessler and R. A. Wolfe41 andR. W. Engstr0m.4~ In America, where the cells were available some yearsago, the direct measurement of the intensity of lines in the emission spectrumhas been carried out in numerous lab~ratories,~~ and with the developmentof ultra-violet transparent envelopes this method has now become estab-lished and commercial direct-reading spectrographs are marketed by a tleast two scientific instrument manufacturers.&These instruments allow direct measurement of the intensities of up to16 predetermined spectrum lines, and hence, as one line is employed as aninternal standard, the determination of the concentration of 15 minor con.stituents can be carried There seems little doubt that this methodof spectrographic analysis is still in its infancy, but even so it shows manyvaluable advantages over the more orthodox procedures employing photo-3B J.A. Rajchman and R. L. Snyder, EEectronics, 1940, 13, 20; K. Zworykin and40 R.C.A. Manufacturing Co. Inc., Harrison, N. J.; Cosmos Manufacturing Co.41 J . Opt. SOC. Amer., 1947, 37, 33.43 D. H. Rank, R. J. Pfister, and P. D. Coleman, ibid., 1942, 32, 390; D. H. Rank,R. J. Pfister, and H. H. Grimm, ibid., 1943, 33, 31 ; E. A. Boettner and G. P. Brewing-ton, ibid., 1944, 34, 6; G. A. Nahstoll and F. R. Bryan, ibid., 1945, %, 646; M. F.Hasler and H. W. Dietert, ibid., 1944, 34, 751; M. F. Hasler, J. W. Kemp, andH. W. Dietert, A.S.T.M. Bull., 1946, No.139, 22; J. L. Saunderson, V. J. Caldecourt,and E. W. Peterson, J . Opt. Soc. Amer., 1945, 35, 681; G. H. Dieke and H. M. Cross-white, ibid., p. 471 ; J. L. Saunderson and T. M. Hess, Metal Progress, 1946, 49, 947.44 Applied Research Laboratories, Glendale, California ; Baird Associates, Cam -bridge, Mass.dB Applied Research Laboratories, Glendale, California. Trade literature on the“ Spectrograph Quantometer Adaptor.”J. A. Rajchman, Proc. I.R.E., 1939, 2’7, 558.Ltd., Brimsdown, Middlesex.42 Ibid., p. 420324 ANALYTIOAL UHEMISTRY.graphic recording of spectral line intensities. The main advantage of themethod is its speed, and it is generally claimed that a sample can be analysedfor ten elements in under 3 minutes. The choice of spectrum line pairs ismade easier since a much wider range of intensities can be measured thanis practicable using photographic means; G.H. Dieke and H. M. Cross-white,"6 for example, report that they have successfully used a pair of Lineswhose relative intensity ratio was 1 : 40,000. On the other hand, the com-paratively large size of the photomultipliers, or of the mirrors used to directthe images of the spectrum lines on to them, makes it difficult to use lineswhich are close together.It is apparent that this type of instrument is most valuable in thoseapplications where large numbers of similar samples have to be analysed,and it is therefore eminently suitable for use in the control laboratories oflarge metallurgical works. When a complete survey of a material is requiredor when its impurities or constituents are not known the photographicmethod is of greater value, although direct-reading instruments in whichthe whole of the spectrum can be scanned by zt single photocell can beused for this purpose.The main disadvantage of direct-reading instruments is their high cost ;a high-dispersion spectrograph is essential for a full application of themethod, and the commercial instruments incorporate a specially designedgrating spectrograph of the required characteristics ; the recording apparatusis far from simple and for the best results a high-power controlled sourceunit is used for excitation.It is generally claimed that the analytical accuracy of such an equip-ment is a t least as high as the orthodox photographic method, and that,since the intensities of the spectrum lines used may vary between widelimits, a greater range of minor constituent concentrations may be sntis-factorily covered.Rage of Appkation.-Although the most marked advances in emissionspectrography in the past ten years have occurred in the analysis of metals,particularly light alloys, progress in other fields has been considerable.Many reviews of the scope of spectrographic methods have appeared in theliterature, and its general application to specific branches of science hasalso been dealt with.For example, B. L. Clarke and A. E. Ruehle4' havereviewed its applications in communications research, V. It. Ells 48 givesdetails of the spectrographic analysis of plant derivatives, and its use inagricultural investigations is reviewed by L. H.Rogers.49 For thesemiscellaneous analyses it is customary to use an arc between carbon orgraphite electrodes, the sample being held in a hole drilled in one or bothof the electrodes. fertili~ers,~~ and plants 53 The analyses of water,5046 J . Opt. SOC. Amer., 1946, 36, 192.48 J . Opt. SOC. Amer., 1941, 31, 634.6o L. W. Strock and S. Dexter, ibid., p. 167.61 R. 0. Scott and R. L. Mitchell, J . SOC. Chem. Id., 1943, 62, 4 ; G. W. Fox andR. A. Goodwin, Iowa State Coll. J . Sci., 1941, 15, 119; R. Q. Parks, J . Opt. SOC. Amer.,1912, 32, 233.47 Bdl System Tech. J., 1938, 17, 381.4s Ibid., p. 260CLAYTON : ANALYTICAL EMISSION SPECTEOGRAPHY . 325are of direct application in agricultural work, whilst in the biological fieldwe find methods ranging from those dealing with food 54 to those whichdeal with traces of metallic and non-metallic derivatives in blood.55 Arcexcitation has also found wide application in the analysis of minerals, ores,and slags,BG and a specific application to cement analysis is described byA.W. H e l ~ . ~ ’Many of these materials, particularly those which are easily taken intosolution, may be analysed by a flame technique.58 An oxy-acetylene flamehas been used for the analysis of fruit and plants,59 and the Lundeghrdhapparatus 6O has been adapted for the analysis of biological material ingenera1.6l H. LundegGrdh and H. Bergstrand 62 has used it for the examin-ation of liver, the material being ashed and dissolved in acid before beingatomised in the flame.Interesting modifications of the flame methodproduced by H. Ramage,63 in which a spill of filter paper is impregnatedwith the solution under test, have been described by M. N. Thruston 64and by F. C. Steward and J. A. Harrison.6” The former method uses acopper arc in which to burn the filter paper, whilst the latter involvesfeeding the spill into the flame a t a controlled rate to ensure regular spectralemission. Further developments in this field are described in Section 3of this Report (2. 326).Por insulating mat’erials a spark technique is usually employed.J. R. Churchill and R. G. Russell 66 pellet the material with sodium fluorideand graphite powder before sparking, and J.van Calker 66 has used 2 solidsample painted with a conducting material to enable the discharge to strike.The halogens and certain non-metals may be detected by using a glowdischarge in the vapour of the material, or by the use of spark excitationa t reduced pressure. Using the spark technique, K. Pfeilsticker 67 hasbeen able to detect the presence of gases in metallic electrodes.62 E. H. Melvin and R. T. O’Connor, Ind. Eng. Chem. Anal., 1041, 13, 520; R. T.O’Connor, ibid., p. 597.63 W. R. Brode and I. W. Wander, J . Opt. SOC. Amer., 1941, 31, 402; B. C. Brun-stetter and A. J. Myers, ibid., p. 163; M. L. Nichols and L. H. Rogers, Ind. Eng. Chent.Anal., 1944, 16, 137.64 J. K. Brody and D. T. Ewing, ibid., 1945,17,627 ; D.A. Warper and N. Strafford,J . SOC. Chern. Id., 1942,61, 74.6 5 A. Tracey and J. McPheat, Biochem. J., 1943, 37, 683.56 J. M. Bray, Arner. Min., 1942, 27, 769; W. W. A. Johnson and D. P. Norman,Astrophys. J., 1943, 97, 46; J. R. Churchill and R. G. Russell, I d . Eng. Chem. Anal.,1945, 1’7, 66; C. G. Carlsson, Jernkont. Ann., 1943, 127, 572; P. D. Korzh, Izvest. Akad.Nauk S.S.S.R., 1945, (Fiz), 9, 665.67 J . Res. Nat. Bur. Stand., 1945, 34, 129.69 M. A. Griggs, R. Johnstin, and B. E. Elledge, Ind. Eng. Chern. Anal., 1941, 13, 99.6o H. LundegBrdh, ‘’ Die quantitative Spectralanalyse der Elemente,” Jena, Gustav61 J. Cholak and D. M. Hubbard, Id. Eng. Chem. Anal., 1944, 16, 728.62 Regiae SOC. Sci. Upmliensis, 1940, 12, 1.63 Nature, 1936, 137, 67.66 Ann.Bot., 1939, 3, 427.6 7 Ibid., p. 424.5 8 Ann. Reports, 1941, 38, 274.Fischer, Vol. 1, 1929; Vol. 2, 1934.64 J . SOC. Chem. Id., 1942, 61, 144.6 6 Spectrochim. Acta, 1940, 1, 403326 AN&YTICAL CHEMISTRY.In the metallurgical field methods have been described for the investig-ation of inclusions and segregates in steel samples,68 and a particularlyinteresting paper on this subject has been written by J. Convey andJ. H. Oldfield.69 In their apparatus the photographic plate moves insynchronism with a traversing spark, and so the image on the plate showsthe point to point variation of the composition of the sample. The require-ments for the application of spectrography to rapid foundry control werediscussed in 1945 by H.W. Dietert and J. A. S~huch,~O and, apart fromthe omission of recent developments in direct-reading equipment, the con-siderations put forward by these authors still apply. The application ofnormal spectrographic equipment to foundry control in England hasrecently been described by H. R. Clayton,71 the analysis having beenaccelerated by shortening the time spent in photographic processing. Inthis method an alloy may be analysed for 5 elements in less than 10 minutes.H. R. C.3. FLAME PHOTOMETRY.The Lundeghrdh method of exciting the emission spectrum of an elementby atomisation of its solution and spraying into an air-acetylene flamehas become firmly established as a standard spectrographic technique (seep. 325). Plame photometry represents a logical development of this pro-cedure whereby the same means of spectrum excitation are employed, butthe subsequent measurement of emission intensity is greatly simplified bythe introduction of relatively cheap filters and direct-reading photocell-galvanometer combinations in place of the expensive spectrograph andassociated equipment required for the photographic recording and deter-mination of line intensities.In the typical flame photometer ordinarylight filters are introduced to select those regions of the spectrum whichcontain euitable spectral lines of the particular element concerned and tocut out any radiation emitted by other elements present in the solution atthe same time. This selection, of course, may be achieved far more pre-cisely by means of monochromators as in the case of the Beckmanspectrophotometer attachment,2 but the introduction of such devicesdetracts considerably from the simplicity and cheapness of the apparatus.The low emission energies available in such methods of direct photometrynecessitate the adoption of extra sensitive means of detection (see p.324).In simple flame photometry the use of relatively wide-band filters and the6 8 F. G. Barker, J. Convey, and J. H. Oldfield, J . Iron Xteet Inst., 1941,144, 143 P ;R. Weihrich and W. Schwarz, Arch. Eisenhuttenw., 1941, 15, 83; G. Thanheiser andJ. Heyes, ibid., 1940, 14, 543.69 J . Iron Steel Inst., 1945, 152, 473 P.70 Trans. Amer. Pound. Assoc., 1945, 52, 889.71 J . SOC. Chem. I d . , 1948, 67, 270.1 G.Thanheiser and J. Heyes, Mitt. Kaiser Withelm Inst. Eisertfmsch., 1937, 19,113; 1939, 21, 327; W. H. Jansen, J. Heyes, and C. Richter, 2. physikal. Chem., 1935,A , 174, 291; J. Heyes, Angew. Chem., 1937, 50, 871.2 R. H. Muller, Anal. Chenz., 1947, 19, No. 8, 21aLEYTON : FLAME PHOTOMETRY. 327consequent increase in available radiant energy enables the experimenterto employ less elaborate detectors such as barrier layer cells or photo-electric cells in conjunction with a sensitive galvanometer. Visual methodsemploying filters have also been described but are usually not to be recom-mended for routine work.* The photometer is calibrated against solutionscontaining known amounts of the element under test, the range of con-centration being determined by the sensitivity of the detector galvano-meter combination.For low concentrations, e.g., up to 10 p.p.m. of sodium,a linear relationship has been found between concentration and galvano-meter ‘reading, but for higher concentrations a calibration curve is usuallyrequired.5The key factor in flame photometry is, of course, the efficiency of thefilters in cutting out unwanted radiation. Sodium light is particularlydifficult to eliminate and early attempts to determine potassium in thepresence of sodium by substituting filters for monochromators were onlypartly successfuL6 Combinations of filters such as Jena (Schott) typesRG9 and BG17 proved to be more efficient than single filters. W. Xchuh-knecht obtained a satisfactory separation using a combination of threefilters, BG19, RG8, and BG3, and by means of a gas-filled photocell andsensitive galvanometer, was able to determine potassium in solution aschloride with an accuracy of f5y0 over the range 0.04-0-008% of K20.He claimed that interference due to sodium, calcium, and magnesium, alsopresent in the solution, was negligible.In 1938 a flame photometer based on this design was produced by thefirm of Zeiss for the routine determination of potassium.It employed agravity feed for the test solution to the atomiser, and a special filter : thefiltered radiation was measured with a cmium photocell and mirror galvano-meter. At the same time Messrs. Siemens introduced a model with asuction feed, an all-glass atomiser, and a single filter (RGS) : by means of astabilised amplifier, the phot’ocell currents could be read on an ordinarymilliammeter.Both these instruments underwent exhaustive tests in theanalysis of plant, food, and fertiliser extract^,^^ and in general the resultsagreed well with the figures for potassium as determined by chemicalanalysis, down to a concentration of 20 mg. of K20 per 100 C.C. The out-standing feature of this new technique was the ease and rapidity withwhich the analyses could be made, the average time for each determinationbeing about 2 minutes. The majority of the investigators found the photo-cell-galvanometer combination to be more reliable as a means of detectionbecause of instability in the photocell amplifier. Using a similar techniqueand the combination of filters RC.19, RGS, and BG3, H.LundegBrdh andS. Coy, Angew. Chem., 1937, 50, 301.Ind. Eng. Chem. Anal., 1945, 1’7, 605.F. Kertscher, Bodenk. Pjlanz., 1938, 10, 758; W. Lehrnann, ibid., p. 766; F. Gei-secke and W. Rathje, ibid., p. 776; L. Rohmlehrer, Mezogs. Kutat,, 1944, 17, 51 ;Chem. Abs., 1947, 41, 7165.* L. Schmitt and W. Breitweiser, Bodenk. PJEanz., 2938, 10, 750.ti Jansen, Heyes, and Richter, loc. cit., ref. 1. Anyew. Chem., 1937, 50, 299328 ANALYTICAL CHEMISTRY.K. Boratynski concluded that the method might be used successfullyfor the routine determination of potassium over the range 0.00025-0.004~.with an accuracy of &lo%.Further work revealed that interference due to the presence of otherelements, particularly calcium in soil extracts, could seriously affect theaccuracy of the potassium determinations. Substitution of the filter RG8 byRG9 improved the performance of the instrument, but it was still unsatis-factory and various other suggestions were made to overcome this inter-ference such as precipitation of the calcium and the use of illuminatingga,s instead of acetylene, whereby the intensity of the calcium radiationwas reduced owing to the lower flame temperature produced.lO Theaddition of ammonium phosphate and calibration of the instrument withpotassium in ammonium nitrate solution was also recommended.l1Various modifications were proposed, particularly in the design of theatomiser and burner, to increase the accuracy and adaptability of theapparatus and to allow for the substitution of ordinary illuminating gas.12S.D. Boon l3 discusses in some detail the development of the flame photo-metric technique and gives much valuable information as to the relativemerits of different types of filters and photocells together with a descriptionof the apparatus used in his investigations. A somewhat similar design hasbeen described for the determination of sodium and potassium in biologicalfluids and for the determination of serum potassium using an Ilfordfilter 609 and Cintel GS1S photocell.15 Results obtained with this photo-meter agreed with chemical determinations of potassium within 2 nig.per 100 C.C. Filters based on compounds of the rare earths praseodymium,neodymium, and dysprosium (e.g., Wratten No.77, Chance ON16) havestrong absorption bands in the region of the intense sodium lines (5890,5896 A.) and have been used successfully for the elimination of this element.describe amuch more compact apparatus designed for routine laboratory use, incor-porating a metal atomiser with gravity feed, an ordinary Meker-type Fisherburner, and a barrier-layer cell with galvanometer. Domestic coal gas isused, and the monitoring of the gas and air supplies is achieved by pressuregauges instead of the more cumbersome manometers of earlier designs.Various Corning glass filters are described for the determination of sodium,potassium, calcium, and lithium. A number of experimental models basedR. B. Barnes, D.Richardson, J. W. Berry, and R. L. HoodSvemk Kern. Tidskr., 1938, 50, 136.lo H. Riehm, Bodenk. P&nz., 1945, 36, 109.l1 K. Nehring, Chim. et Ind., 1942, 30, 36; G. Varrallyay, Mezogs. Kutat., 1944,17, 95; Chirn. et Id., 1946,56, 413.l2 H. Riehm, Bodenk. PJEanx., 1940,21/22, 277 ; E. Rauteberg and E. Knippenberg,ibid., 1940, 20, 364; Erniihr. P$anz., 1941, 37, 73; H. Riehm, Bodenk. PjZanz., 1942,28, 246; R. Hermmn and P. Lderle, ibid., 1942, 30, 189; R. Hermann, Forsch.Dienst, 1943, 16, 239.l3 “ Vlam-fotometrie,” D. B. Centen’s, Amsterdam, 1945.l4 W. R. Domingo, W. Klyne, and W. Weedon, Biochem. J., 1948,42, xxxvi.l5 W. Klyne, ibid., 1948, 43, xxvLEYTON FLAME PHOTOMETRY. 329on this design were produced by the American Cyanamid Co., but a similarmodel made by the Perkin Elmer Corporation is commercially available.Using these instruments, the applicability of the flame photometric tech-nique has been thoroughly investigated.16 The design of the atomiserwould appear to be most critical, and in particular cases metal typeswith suction feed were found preferable to all glass types.Further im-provements in design have also been suggested.ls Satisfactory results, itis claimed,l’ could only be obtained when a more uniform gas supply(cylinder gas) was substituted for the mains supply.The technique involves a number of possible sources of error : (a) Vari-ations in the gas and air supplies which affect the temperature of the flameand therefore the intensity of emission; ( b ) non-uniformity of the spraywhich is dependent upon the air pressure and atomiser ; (c) surface-tensionand viscosity differences between standard and test solutions affecting therate of atomisation; (d) mutual interference between elements in theflame; and ( e ) filter limitations.Most of these factors have been discussedin relation to the flame excitation technique as used in spectrographicwork and are admirably reviewed by R. L. Mitchell and others.20 Forpure solutions, results consistent within A3 yo have been obtained withoutundue diffi~ulty,~ but for complex solutions, like biological extracts, extraprecautions are necessary. The presence of acids, bases, or salts affectsthe accuracy of the analyses to a varying degree according to their con-centration in the solutions.Most biological extracts, for example, areobtained by acid digestion, but because of their interference in the extracts,acids cannot be used indiscriminately. Certain acids are particularlytroublesome; the presence of O - O l ~ o of phosphoric acid is sufficient tocause a decrease of 14% in the estimation of sodium and 9% in that ofpotassium compared with the readings obtained for these two metals inpure solutions.21 Even in pure solutions, the nature of the anion affectsthe calibration of the instrument and must therefore be taken into con-sideration. Errors due to the presence of other cations are generally smallunless they occur at a concentration equivalent to or greater than thatof the test element, in which case they may interfere quite seriously andmust be allowed for.Alcohol and acetic acid give rise to positive errorsin the determination of potassium and sodium in all cases where they occurat concentrations greater than l”/.21 It is therefore evident that greatl6 0. J. Attoe and R. Truog, Soil Sci. SOC. Amer. Proc., 1946, 11, 221; R. It. Over-man and A. K. Davis, J . Biol. Chem., 1947, 168, 641; P. 31. Hald, ibid., 1947, 167,499; T. D. Parkes, H. 0. Johnson, and L. Lyklren, AmZ. Chem., 194S, 20, 827; S. J.Toth, A. L. Prince, A. Wallace, and D. S. Mikkelson, SoiZSci., 1948, 66, 459.l7 Hald, loc. cit., ref. 16.A. T. Myers, I d . Eng. Chem. Anal., 1946, 18, 555; V. Toscani, ibid., 1947, 19,“ The Spectrographic Analysis of Soils, Plants and Related Materials,” Tech.820.Comm.Bur. Soil Sci., 1948, No. 44.2o H. C. T. Stace, J . Proc. Austral. Chem. Inst., 1947, 14, 144.21 Parkes, Johnson, and Lykken, loc. cit., ref. 16330 ANALYTIUAL CJHEMISTRY.care has to be taken before the simple flame photometer may be used fara particular investigation.The usual procedure adopted has been to calibrate the photometer withsolutions approximating in composition to that under test, and in thisway fairly reliable results can be obtained. This method, however, is notalways practicable, and for this reason an internal-standard technique hasbeen suggested22 whereby any change affecting the light intensity due toone element affects the internal standard in the same way. Using a speciallymodified photometer to enable them to measure independently the radiationdue to both test element and internal standard, the authors have appreciablyincreased the accuracy of the technique. By adopting the standard methodof analysis with this modified instrument it becomes quite feasible todetermine two elements in the same solution at the same time.The flame photometric technique has been successfully used for thedetermination of boron as methyl borate with a sensitivity down to 5 pg.of the element per ml.l3 Other rapid methods for the determination of thiselement based on similar principles have also been described.2*Hence, although flame photometry is obviously a rather crude techniqueand certainly limited in its applications, it nevertheless possesses certainadvantages over spectrographic methods, particularly when factors like costand simplicity in operation have to be considered.Constructional andmaintenance costs are negligible compared with those of the more elaboratespectrograph, and with a certain amount of care and preparation, consistentresults can be obtained even by relatively unskilled operators. The methodhas already proved to be particularly valuable for the routine determinationof sodium, potassium, and calcium in biological fluids and extracts, butmight well be adapted for the analysis of other elements which are excitedat flame temperatures provided that satisfactory filters can be found.L. L.4. VOLUMETRIC ANALYSIS.much work has been carried out in this important but unrewarding field,and many valuable collaborative studies have been sponsored by theAssociation of Official Agricultural Chemists.Dipotassium paraperiodate,K2H,10,,3H,0,2 salicylic acid,3 and o-chlorobenzoic acid 4 have been pro-posed as acidimetric standards, but although sulphamic acid, NH2*S03H,Solutions and Standards for Volumetric Analysis.-Since the last Reporta2 J. W. Berry, D. G. Chappell, and R. B. Barnes, Id. Eng. O h . AmZ., 1946,2* J. S . McHargue and R. K. Calfee, ibid., 1932, 4, 385; 1937, 9, 288; H. C. Weber18, 19.and R. D. Jacobson, ibid;., 1938,10, 273.Ann. Reports, 1937, 34, 480.L. Mdaprade, Cong. Chim. id., Compt. rend. 18me Cong., Nancy, 1938, 91;Chern. Abs., 1939, 33, 6192.3 E. Latiu, 2. anal. Chem., 1943, 126, 184.I.G. Murgulescu and V. Alexa, &id., 1943,1!%, 260IRVING : VOLUMETRIC ANALYSIS. 331has the advantage of being a strong acid and relatively soluble in water,6hydrochloric acid prepared by the constant boiling-point method @tillappears to be more exact and convenient to prepare.6It is now generally agreed that a temperature of 300" should not beexceeded when heating sodium hydrogen carbonate for the preparation ofanhydrous sodium carbonate,' but W. R. Carmody states that up to0.1 % of water is held tenaciously but can be partly eliminated by powderingand re-igniting. The standardisation of acids against sodium carbonate andborax has been studied c~llaboratively,~ and W. Young lo proposes 8-di-phenylguanidine as a primary standard, and A. J.Berry l1 advocatesthallous carbonate, which has a high equivalent weight and serves as alink with iodornetric standards since it is quantitatively oxidised by iodatein acid solution to the thallic state. Silver hydroxide prepared from puresilver has been used to standardise acids, halides, thiocyanate, and silvernitrate.12The stabilisation of solutions of sodium thiosulphate continues to attractattention,13 though it appears that sterile solutions of pH not greater than6.2 maintain their titre for long periods.l* C. W. Jordan l5 deprecates theuse of borax as a preservative, but to safeguard against adventitious inocul-ation by sulphur bacteria, sodium benzoate,16 chloroform,17 mercuriciodide,l* and amyl l 9 and octyl20 alcohol have been suggested.Chloroformand mercuric iodide effectively stabilised solutions stored a t 40" for twomonths, but alkalis promoted decomposition.18 Although pure crystallinesodium thiosulphate pentahydrate slowly decomposes in the solid state,21the anhydrous salt is thermally stable for 79 days a t 120" and has beenproposed as a primary standard.22 Changes in the composition of standardti S. M. J. Butler, G. F. Smith, and L, F. Audrieth, Ind. Eng. Chem. Anal., 1938,10, 690.W. H. King, J . Assoc. 08. Agric. Chem., 1942, 25, 653.Ind. Eng. Chem. Anal., 1945, 17, 577.L. Vandaveer, J . Assoc. OBc. Agric. Chena., 1939, 22, 563; H. W. Conroy, ibid.,' L. Ramberg, Svemk Kem. Tidskr., 1940, 52, 137.1941, 24, 636.lo Canadian J . Res., 1939, 17, B, 192.l1 Analyst, 1939, 64, 27; cf.E. Jensen and B. Nilssen, Ind. Eng. Chem. Anal.,l2 L. G . Escolar, Anal. Pis, Quim., 1945, 41, 1071, 1086; 1946, 42, 203, 211.l3 Ann. Reports, 1935, 32, 454.l4 J. L. Kassner and E. E. Kassner, fnd. Eng. Chem. Anntl., 1940, 12, 655; G. M.lb Arner. J . Pharm., 1938, 110, 316.l6 J. Ehrlich, Id. Eng. Chem. Anal., 1942, 14, 406.1939, 11, 508.Johnson, J . Assoc. Off. Agric. Chem., 1942, 25, 659; 1945, 28, 594.Krassner and Kmsner, loc. cit., ref. 14; S. 0. Rue, Id. Eng. Chem. Anal., 1942,Johnson, bc. cit., ref. 14; A. Baudouin and (Mlle.) P. Hillion, Bull. Soc. Chim.14, 802. 18 Idem, ibid.biol., 1944, 26, 490.2o Idem, ibid.22 13. M. Tomlinson and F. GI. Ciapetta, iba., 1941, 13, 639.V. K. LaMer and H. M. Todinson, I d .Eng. Chem. A w l . , 1937, 9, 688332 ANALYTICAL CHEMISTRY.iodine solutions have been discussed by C. K. and for standardis-ation of thiosulphate it is invariably obtained from potassium iodide byoxidation with potassium dichromate 24 (a reaction effectively catalysed bycupric ions 25), or by potassium iodate or better cupric perchlorate ; 26addition of potassium thiocyanate improves the e n d - p ~ i n t . ~ ~Pure potassium iodide has been prepared 28 and examined as a primarystandard in permanganatrometry29 and arsenious oxide can be used inpreference to oxalate if a suitable catalyst (e.g., iodine chloride) is pre~ent.~OOther oxidants such as potassium di~hrornate,~~ iodate,32 br~mide-bromate:~and cerate solutions 34 have been carefully studied, and E.C. Deal 35 reportson the standardisation and stability of thiocyanate solutions. Solutions ofsodium hypochlorite retain their titre in the and when stronglybasified37 and are preferred t,o bromate in the determination of antimonyand other ~ u b s t a n c e s . ~ ~ , ~ ~ For some purposes they can be replaced bysolutions of chloraniine-~.~~ More work has been carried out on the reactionsof sodium chlorite,40 and its potentialities as a volumetric reagent.41 Whereacidified bromate-bromide mixtures are inappropriate a solution of brominein potassium bromide can be stored and dispensed from apparatus describedby A. J. Henry.42With regard to reducing agents, stable solutions of mercurous per-chlorate have been used for the determination of ferric iron though thereaction is not strictly stoi~heiometric.~~ Agreement has not yet beenreached on the best means of standardisiiig titanous chlorideu but theuse of buffers to increase the pH and raise its reduction potential is well23 J .Arner. Pharm. ASSOC., 1948, 37, 6.24 Johnson, Zoc. cit., ref. 14.26 J. J. Kolb, Ind. Eng. Chem. Anal., 1944, 16, 38.27 G. C. Oglethorpe and C. G. Smith, AnaZyst, 1943, 68, 325.28 J. J. Lingane and I. 31. Kolthoff, “Inorganic Syntheses,” New York, 1939,29 I. M. Kolthoff, H. A. Laitinen, and J. J. Lingane, J . Amer. Chem. SOC., 1937,ao D. E. Metzler, R. J. Myers, and E. H. Swift, Ind. Eng. Chem. Anal., 1944,16, 625.3 1 J. R. Pound, Chew&. Eng. Min. Rev., 1945, 38, 87.32 S. M. Berman, J .Assoc. Off. Agric. Chem., 1937, 20, 590.33 H. C. Van Dame, ibid., 1947, 30, 502.34 G. F. Smith and C. A. Getz, I d . Eng. Chem. Anal., 1940, 12, 339.35 J . Assoc. Off. Agric. Chem., 1942, 25, 661; 1945, 28, 595; 1947, 30, 496.36 J. Bitskei, Magyar Chem. Pol., 1944, 50, 97.N. I. Goldstone and M. B. Jacobs, Id. Eng. Chem. Anal., 1944,16, 206.38 J. Bitskei and K. Petrich, Magyav Chem. Lapja, 1947, 2, 230.39 D’Costaa C,. Macris, Ann. Chim. analyt., 1946, 28, 165; B. Samek, C?:asopsiS4o M. C. Taylor, J. F. White, G. P. Vincent, and G. L. Cunningham, Id. Eng.41 D. T. Jackson and J. L. Parsons, Ind. Eng. Chem. Anal., 1937,Q, 14; L. F. Yntema42 Analyst, 1945, 70, 259.43 W. Pugh, J., 1945, 588.44 J. E. Breit, J . Assoc. 08. Agric. Chern., 1947, 30, 504.25 B.D. Sully, J . , 1942, 366.p. 163.59, 429; 1039, 61, 1690.Czechoslov. Le‘k., 1941, 21, 77.Chem., 1940, 32, 899.and T. Fleming, ibid., 1939, 11, 375IRVING : VOLUMETRIC ANALYSIS. 333established.45 J. E. Lindsay 46 has examined electrolytic iron as a standard,and ferrous ethylenediamine sulphate, [C2H4(NH,)2]2S04,FeS04,4H20, isfound to be much more stable than Mohr's salt.47 P. R. Duke 4s ensurescomplete reduction of standard ferrous solutions by running them down acolumn of lead amalgam just before use. The simple and direct preparationof chromous chloride or sulphate solutions of determinate concentrationdescribed by J. J. Lingane and R. L. Pecsok 49 should facilitate the extendeduse of this powerful reducing agent whose storage, standardisation, andreactions have recently been reviewed.@, 5ORapid methods have been described for preparing standard solutions ofalmost all the reagents in conimon use in volumetric analysis.51 Whenthese are dispensed from a large storage reservoir and replaced by dry airthe evaporation of water to restore saturation conditions must cause anincrease in the concentration of the residual solution, but H.A. Liebhavsky 52has shown that; the error is quite negligible.In view of the great importance of accurate pH measurements to theanalyst it will not be inappropriate to recall that the pH of O.O5~-borax isnow stated 53 to be 9-18 a t 20". Acid salts of benzoic, phenylacetic, andother organic acids give highly buffered solutions suitable as pH standards,S4and saturated potassium hydrogen tartrate solution is said to be betterthan aqueous potassium hydrogen phthalate.55Apparatus.-Drastic modification in the design of apparatus for macro-volumetric analysis is scarcely to be expected, though minor improvementscontinue to be made. For instance, J. T. Stock and M. A. Fil156 proposetwo methods of modifying burette taps to effect finer control of delivery,and F. C. Guthrie 57 describes a simple reading device. Copiously illustratedand referenced reviews of microvolumetric apparatus have been given byG. H. Wyatt,58 and by R. Belcher and C. L. Wils0n.~9 On this scale taplessburettes are increasingly used.60 An entirely new type of microburettedesigned by J. A. Saunders,61 an electrically operated burette,62 and devices46 0.L. Evenson, ,T. Assoc. Off. Agric. Chein., 1945, 28, 633; P. G. Butts, W. J.46 Chemist Anulyst, 1942, 31, 8.47 K. P. Caraway and R. E. Oesper, J. Chem. Educ., 1947, 24, 235.48 Ind. Eng. Chem. Anal., 1945, 17, 530.49 Anal. Chem., 1948, 20, 425.50 H. W. Stone, ibicE., p. 747; R. Flatt and F. Sommer, Helv. Chim. Acta, 1942, 25,51 E. Shulek and F. Szegho, 2. anal. Chem., 1942, 123, 252.52 Ind. Eng. Chem. Anal., 1944, 16, 349.ti3 A. D. E. Lauchlan, Nature, 1944, 154, 577.64 J. C. Speakman and N. Smith, ibid., 1944, 165, 698.6 6 J. J. Lingane, Anal. Chem., 1947, 19, 810.5G Analyst, 1946, 71, 142. Bi Chem. and Ind., 1947, 240.5 8 Analyst, 1944, 69, 81, 180. 59 Metcsllurgia, 1946, 34, 337; 35 47.6o I.Liitgert and E, Schroer, 2, physikal. Chem., 1941, 49, B , 257.61 Analyst, 1946, 71, 528.62 F. C. Nrtchod, I d Eng. Chem. Anal., 1945, 17, 602.Meikle, J. Shovers, D. L. Kouba, and W. W. Becker, Anal. Chem., 1948, 20, 947.684334 ANALYTICAL CHEMISTRY.for varying the rate of efflux 63 and for obtaining drops as small as 0.1 mm.in diameter 64 may also be noted. By fabricating a glass electrode in theform of a re-entrant bulb of capacity -1.5 ml. W. Ingold 65 is able totitrate 300-900 pg. of acid with an accuracy of &Is%. The principle ofthe hypodermic syringe from which the displacement of liquid is controlledby a micrometer screw underlies many precision micro-pipettes and burettesdescribed recently.66 When such apparatus is motor-driven, the rate andextent of the delivery of titrating fluid can be controlled by potentialchanges of indicator electrodes in solution so that potentiometric titrationscan be carried out and recorded automatically.6~ An alternative system inwhich the titrant is added a t a constant rate has been described by GonzalezBarredo and Taylor.66 Benedetti-Pichler has considered the possible errorsarising from the evaporation of standard solutions from the tips of niicro-burettes68 and describes the technique of titration with pg.samples wherea low-power microscope is needed to observe operations conducted with theaid of mechanical manipulators.69Titrations in Non-aqueous Solvents.-Where the material to be titratedis insoluble in water, solvents such as ethyl, n-butyl, and amyl alcohol oracetone have often been substituted.A. E. Ruehle 70 extends the range todioxan and ethylene glycol monoalkyl ethers (Cellosolves) with anisolerecommended as a solvent for pitches and asphalts in titrations againstpotassium hydroxide and sodium butoxide.use alcohol or naphtha as a solvent for thiols in titrations with copper alkylphthalates.That non-aqueous solvents may provide a solution to the problemsinvolved in determining certain salts, or acids and bases too weak fortitration by conventional methods in aqueous solution, follows from aconsideration of Bronsted’s equationE. Turk and E. E. ReidHA + S HS+ + A-For if the solvent S used is more basic than the conjugate base A- of theacid HA which is to be determined, equilibrium will be displaced appreciablyto the right.Acids whioh are weak in water will thus appear stronger in amore basic solvent. Conversely, weak bases will appear stronger whenwater is replaced by a more acidic solvent, as was first demonstrated experi-63 J. T. Stock and M. A. Fill, Metdlurgia, 1944, 31, 103; F. P. W. Winteringham,Analyst, 1945, 70, 173.e4 W. R. Lane, J. Sci. Imtr., 1947, 24, 98.66 Helv. Chim. Acta, 1946, 29, 1929.86 P. A. Shaffer, P. S. Farrington, and C. Niemann, Anal. Chem., 1947, 19, 492;cf. G. H. Wyatt, Metallurgia, 1945, 32, 240; V. Stott and (Miss) I. H. Hadfield, B.P.584,841 ; J . J. Lingane, Anal. Chem., 1948, 20, 285; H. A. Robinson, Trans. Electro-chern. SOC., 1947,92, Preprint 38, 503 ; J.M. Gonzalez Barredo and J. K. Taylor, ibicE.,Preprint 26, 303.6’ Lingane; Robinson, Zocc. cit.88 A. A. Benedetti-Pichler and S. Siggia, I d . Eng. Chem. Anal., 1942,14, 662.1 3 ~ A. G. Loscalzo and A. A. Benedetti-Pichler, ibid., 1945, 17, 187.70 I d . Eng. Chem. Anal., 1938, 10, 130. 71 Ibid., 1946, 17, 713IRVING : VOLUMETRIC ANALYSIS. 335mentally by N. F. Hall and J. B. Conant.72 For reactions with glacialacetic acid as solvent the titrant is prepared by adding acetic anhydrideto aqueous perchloric acid in proportion to its water content, diluting withacetic acid to the desired strength, and standardising against anhydroussodium carbonate. '3 Blumrich and Bandel 73 found t h a t primary, secondary,and tertiary amines (but not amides of carboxylic acids or acetylatedamines) could be titrated potentiometrically : the titre after acetylationof a mixture thus gave the amount of tertiary amine alone.73 Up to 50%of water in a sample is admissible but a special procedure must be adoptedwhen sterically hindered secondary arnines are present, 74 Since salicyl-aldehyde condenses with ammonia and primary (but not secondary ortertiary) amines to form azomethines of decreased basicity, a method becomesavailable for determing all the components of an ammonia-amine mixture. 75When less than 0.274 of water is present, many organic bases and amino-acids and alkali, alkaline-earth, and ammonium salts of carboxylic acidsbehave as strong bases in glacial acetic acid and can be titrated with 0 4 N -perchloric acid, crystal-violet, thymol-blue, and neutral-red being used asvisual indicators.76 a-Naphtholbenzein is preferred for dimethylaniline 77and quinine, the latter titrating as st di-acid base.78 In chloroform thecinchona bases and nicotine are accurately titratable as di-acid bases withtoluene-p- sulphonic acid and picric acid, respectively , dimeth yl- yell0 w beingthe indicator.However, in aqueous alcohol they both behave as mono-acid bases towards mineral acids (methyl-red) thus permitting an assay ofnicotine in tobacco.79 Salts of weak monobasic organic acids (notably the" soaps ") dissolve quite readily in 1 : %glycols and better still in admixtureswith higher aliphatic alcohols or chlorinated solvents and can be titrateddirectly with solutions of hydrochloric, perchloric, or other strong acids inthe same solvent, the end-point being determined potentiometrically orvisually.80 Phenolphthalein and methyl-red can be used in a double-indicator method to determine free alkali and soap, and salts of inorganicacids such as metaborates, aluminates, etc., mixtures of weak and strongacids, and weak bases can be determined in the same solvent.8lWeak acids can be titrated if the solvent is more basic than water, butto minimise solvolysis it should have a small autoprotolysis constant and thetitrant must naturally be even more basic than the solvent.Using an-hydrous ethylenediamine as solvent and sodium 2-aminoethoxide as titrant,72 J . Amer. Chem. SOC., 1927, 49, 3047, 3062; 1930, 52, 5115.73 K.Blumrich and G. Bandel, Angew. Chem., 1941, 54, 374; H. Haslam and74 C. D. Wagner, R. H. Brown, andE. D. Peters, J . Amer. Chem. SOC., 1947, 69, 2609.75 Idem, ibid., p. 2611.713 J. C. Oppenheim, J . Soc. Chem. Ind. Victoria, 1945, 45, 647.?7 Haslam and Hearn, loc. cit., ref. 4.7 8 R. L. Herd, J . Amr. Pharm. Assoc., 1942, 31, 9.7 O E. M. Trautner and 0. E. Neufeld, Australian Chem. Inst., 1946, 15, 70.8o S. R. Palit, 14. Eng. Chem. Anal., 1946, 18, 246.P. F. Hearn, Analyst, 1944, 69, 144.Idem, Oil and Soap, 1946, 23, 58336 ANALYTICAL CHEMISTRY.M. L. Moss, J. H. Elliot, and R. T. Hall82 find that aromatic carboxylicacids and phenols behave as strong acids and give very satisfactory inflec-tions in potentiometric titration curves.Amino-acids titrate as simplecarboxylic acids arid salicylic acid behavcs as a dibasic acid. Even resorcinolgives two inflections, the second being that of a very weak acid, and allthree stages of dissociation of boric acid are detectable. In acetic anhydrideas solvent, sodium acetate acts as a strong base, changing. indicators such asmethyl-orange to their alkaline colour and reacting instantaneously withtrichloroacetic acid and more slowly with acid ~hlorides.8~In addition to work in aqueous alcoh01,~4 acefone,B5 and glacial acetica~id,~2-789 s6 there are many scattered observations relating to titrations innon-aqueous solvents and there can be little doubt that this subject willsteadily gain importance as its potentialities come to be more generallyrealised.Coulometric Analysis.-The previous sections will have exemplifiedevolutionary trends in classical volumetric analysis, and the search forgreater speed and accuracy with ever smaller samples of material.Theinconvenience of having to prepare standard solutions, the difficulties inherentin their maintenance, and problems of burette design and instrumentationcould be circumvented if the titrant could be generated in situ by an electro-lytic method. This was first realised experimentally by L. Szebellkdy andZ. Somogyi ,S7 who standardised hydrochloric acid by adding potassiumchloride and passing an approximately constant current between a platinumcathode and a silver anode until the change in colour of bromocresol-greenshowed that neutralisation was complete.The quantity of electricityemployed was measured by a silver weight coulometer in series and theextent of chemical action was calculated from this, and the known valueof the Paraday, 100% current efficiency being assumed. This procedure,described appropriately as coulometry, was extended to the standardisationof sulphuric acid, and coulometric determinations of thiocyanate, hydrazine,hydroxylamine, and even caustic alkali could be effected by generatingbromine electrolytically.Though capable of very precise results, applications were limited (sincethe electrode potentials were not controlled) to cases where a single cellreaction could take place and where a specific indicator was available,whilst the use of a weight coulometer was an obvious disadvantage.Nowall oxidation-reduction processes involve electron transfer ; and whether thisis effected electrolytically a t suitable electrodes or by means of an appro-priate ovidising or reducing standard solution is dictated sometimes bychoice, sometimes by necessity. Though Szebelledy and Somogyi appliedAnal. Chem., 1948, 20, 784.83 M. Usanovitsch and K. Jazimirski, J. Qen. Chem. Russk, 1941, ll, 957.84 H. Baggesgaard-Rmmussen, 2. anal. Chem., 1936, 105, 269.85 G. M. Richardson, Proc. Roy. SOC., 1934, B, 115, 121, 142, 170, 180.86 I. M. Kolthoff and A. Willan, J . Amer. Chem. SOC., 1934,56, 1014; G . F. Nadesuand L. E. Branchen, ibid., 1935, 57, 1363.2. anal. Chem., 1038, 112, 313, 323, 332, 385, 391, 395, 400IRVlNa : VOLUMETBIC ANALYSIS.337their coulometric technique only to familiar volumetric determinations, nosuch arbitrary limitation is necessary, for all electrochemical determinationscan legitimately be included within its scope. Provided the electrodereaction is reproducible and exactly defined in a stoicheiometric sense, itneed be neither chemically nor thermodynamically reversible. Withmixtures of reducible ions, control of potential becomes imperative, andJ. J. Lingane 88 points out that a mercury-pool cathode with a silvsr-silverchloride anode possesses many advantages since it is relatively easy toobtain current efficiency in the electrolytic reduction of certainorganic compounds and various metal ions,g0 whilst conventional polaro-graphic methods serve to establish optimum conditions of cathode potentialand electrolyte composition and concentration for any specific determin-ation.Lingane developed a hydrogen-oxygen coulometer as a direct-reading instrument to indicate continuously the progress of an electrolysis,88and the potential control can be effected manually or automati~ally.~~During electrolysis a t constant potential the current decreases expon-entially with time, and each determination would theoretically require aninfinite time for its completion. In practice 99% reduction is achieved(irrespective of the initial concentration) by the time the current has droppedto 1% of its original value and little is gained by pursuing the electrolysisfurther.If a constant electrolysing current is employed some means ofdetecting the end-point must be provided. J. Epstein, H. A. Sober, andS. D. Silvers2 determine acid gases in the air (or materials which can bepyrolysed to acids) by absorbing them in the cathode chamber of a U-shapedelectrolysis vessel and titrating with hydroxyl ions generated by the elec-trolysis of sodium bromide. The end-point is determined potentiometricallyby a Pinkhof system, and since a constant current is employed the timetaken for complete neutralisation is a measure of the acid present.Unstable bromine solutions are an inconvenient feature in the deter-mination of di- (2-chloroethyl) sulphide by oxidation of thiodiglycol preparedtherefrom by hydrolysis) to its sulphoxide, and J.W. Sease, C. Niemann,and E. H. Swift eliminate them by generating the bromine electrolyticallyin an apparatus suitable for the determination of pg. quantities of thiodi-glycol 93 or 30-1000 pg. of arsenic.94 The constant current of less than10 ma. is derived from a dry storage battery, and the coulometer isreplaced by a stop-watch. Polarised electrodes are used to detect the end-point in what is effectively a combination of the dead-stop end-point 95 andan amperometric titration, for since the concentration of bromine in excessdetermines the rate of diffusion of this element to the indicator cathodeand thus the amount of depolarisation, the magnitude of the indicatorcurrent affords a reliable measure of the end-point correction. H.I.88 J . Amer. Chem. SOC., 1945, 67, 1916.so Ibid., 1943, 65, 1348; cf. R. Pasternak, Hel~u. CJ&n. Act& 1948, 31, 753.I d . Eng. Chem. Anal., 1944,16,147. 91 Ibid., 1945, 17, 332.98 Anal. Chem., 1947, 19, 675. 93 Ibid., p. 197.s4 J . arner. Chem. SOC., 1948, 76, 1047. 95 D. P. Evans, Analyst, 1947, 72, 99338 ANALYTICAL UHEMISTRY.5. ANALYSIS OF SEA WATER.There are present in the sea widely different concentrations of a largenumber of inorganic ions as well as colloidal and particulate inorganic andorganic matter. Some fifty elements have already been detected andthe presence of others may be inferred from their occurrence in marineorganisms.2 Of the major elements present some (e.g., sodium and potas-sium) are amongst the most difficult to determine, others (e.g., calcium,strontium, and magnesium) are not easy to separate, and constituents ofgreat biological importance (e.g. , phosphates and nitrates) are present inconcentrations far below those normally dealt with by the microchemist,a few pg./l.being of great importance. The high chloride-ion concentrationand the salt content are constant complicating factors which often rendermodification of conventional methods essential.The major constituents of the oceanic water bear a virtually constantratio to the total salts, being unaffected by land drainage, so that exceptfor special purposes the determination of more than one element is rarelymade. It is usual to determine the silver-precipitated halides (chlorinity).An international standard for chlorinity independent of atomic weights hasbeen maintained by referring all determinations to the so-called Copenhagen‘‘ Normal Water,” which has been established as a permanent standard 3in terms of the mass of silver required to precipitate completely the halogenin one kg. of that water.Using recent values, J. Lyman and R. H. Flem-ing4 give values for the major constituents in terms of chlorinity andsalinity.The concentrations of other elements are affected by biological agencies,and for reason of space attention will be confined to a selection of the mostimportant of these ; the concentrations are expressed in units recommendedby the Association D’Ochanographie Phy~ique,~ and approximate rangesare given for the elements considered.By drawing attention to the marineliterature it is hoped to minimise the regrettable duplication of effort sonoticeable in the analysis of nutrient materials such as phosphate andnitrate which are important in many biological and biochemical studies,and by concentrating on those elements present in minute concentration,the attention of physical chemists may be drawn to a field in which reactionkinetics a t high dilution are of great importance.Phosphorus and Arsenic.-Phosphates (0-4.003 mg.-atom of PO,-P/1.).The earlier work 6 involved either evaporation or precipitation with ferric salts.H. U. Sverdrup, M. W. Johnson, and R. H. Fleming, “ The Oceans,” New York,1942.D. A. Webb, Sci. Proc. Roy. Dublin SOC., 1937, 21, 505.a J.P. Jacobsen and M. Knudsen, Assoc. Oceanog. Physique, Publ. Sci. No. 7, 1940.J . Marine Res., 1940, 3, 134.B. Hellmd-Hwen, J. P. Jacobsen, and T. G. Thompson, Assoc. Oceanog. Physique,D. J. Matthews, J . Marine Biol. ASSOC., 1916, 11, 122; 1917, 11, 251; E. Raben,Publ. Sci. No. 9, 1948.Wksensch. Meermnters., 1916-1920, 18, 1BARNES: ANALYSIS OF SEA WATER. 339W. R. G. Atkins and E. G. Wilson were the first to apply the Denigbsreaction and all subsequent work has been done using this method, a recentsummary of which is given by R. J. Robinson and T. G. Thompson.8Much work has been done on this method of determining phosphates, sincethe element is of great importance to many branches of biochemical work.However, a great deal of the work is repetitive and a fundamental study ofthe reactions and their kinetics is still required.A blue colour can beproduced under the appropriate conditions by the action of many reducingagents upon the heteropoly-acids of molybdic and phosphoric acids andthe intensity of the colour is dependent upon many variables, but for thequantities of phosphate occurring in sea water, only stannous chloridereaches the required sensitivity. K. Kalle's important s t ~ d i e s , ~ much ofwhich were repeated by J. Tischer,lo show that the visual blue is affectedby halides and the absorption in the violet is appreciably higher in seawater owing to the production of yellow tints in the formation of whichmolybdate, chloride, and bivalent tin ions are considered to be involved.L.H. N. Cooper l1 suggested that these yellow colours, particularly notice-able with excess of stannous chloride, are due to the formation of complexmolybdenyl halides and their subsequent hydrolysis. When comparingthe colour developed in sea water with standards made in distilled waterit is necessary to apply a correction for the amount of salt, and since tem-perature affects the colour development, the sensitivity, and the salt error,both the standards and unknown should be a t the same temperature. Aspecial acid molybdate reagent being used, conditions were found under whichthe extinction was proportional to phosphate content and the salt error wasminimal. It was found best to add the stannous chloride in two portionsat an interval of 10 minutes, the intensity of colour being measured5 minutes after the second addition, H.W. Harvey l2 has recently con-firmed and extended these results.Dissolved and particulate phosphorus (0-0.6 mg.-atom of Pll.). I naddition to inorganic phosphate, dissolved organic phosphorus compoundsare present as a result of organic decomposition. Complete oxidation oftraces of organic matter in the presence of large quantities of salts, andthe reduction of the arsenate formed from arsenite during this oxidationwhich is necessary in order to prevent its interference in the subsequentphosphorus determination, give rise to technical difficulties when onlytraces of organic phosphorus compounds are present. K. Kalle andalso others l3 found that the method developed for fresh waters l4 were' Biochem.J., 1926, 20, 1223; J . Marine Biol. ASSOC., 1923, 13, 119; 1925, 13, 700.J . Marine Res., 1948, 7, 33.Ann. Hydrog. Marit. Meteor., 1933, 61, 124; Ber. Deutsch. Wise. Komm. Meere-forschung, 1933, 6, 273; Ann. Hydrog. Marit. Meteor., 1932, 60, 6 ; 1935, 63, 58, 195.lo Z. PJanz. Dung., 1934, 33, 192.l1 J . Marine Biol. ASGOC., 1938, 23, 171.l3 Intern. Rev. ges. Hydrobiol., 1933, 29, 221.L. Titus and V. W. Meloche, ibid., 1931, 26, 441.l2 Ibid., 1948, 27, 337.R. I . Robinson and G. Kemmerer, Tram. Wiscon. Aead. Sci. Arts, 1930, 85, 117340 ANALYTIUAL CHEMISTRY.unsatisfactory. E. Kreps and M. Osadchih l 3 used hydrogen peroxide inthe Oxidation, but Kalle considered that the danger due t o production oforganic acids (e.g., oxalic acid) which would iiiterfere with the phosphorusdetermination renders this reagent unreliable.He therefore fumed thesolid with sulphuric acid with the addition of a little copper salt. F. Berger,15working on marine sediments, showed that Kalle’s method did not give acomplete oxidation, nor were persulphate and perhydrol completely eEec-tive; he recommends fuming nitric acid. Arsenic was not reduced by theearlier workers and Kalle used thiourea for this purpose, but L. H. N. Cooper l6had no success with this method of reduction.A. C. Redfield, H. P. Smith, and B. H. Ketchum l7 used a digestionsimilar to that of Kalle, but effected reduction of arsenate by prolongedheating with sulphite in stoppered bottles.H.W. Harvey l2 has used an alternative method for determining thedissolved organic phosphorus in which considerable modifications areeffected. The organic phosphorus compounds are hydrolysed with acid byautoclaving a t 3 0 4 0 lb./sq. in. for 5-6 hpurs, sulphite being added toprevent oxidation of arsenite.For the phosphorus determination in plankton, L. H. N. Cooper l1found the methods developed by Robinson and Kemmerer l4 and Titusand Meloche l4 to be unsatisfactory owing to the difficulty of removing thelast traces of the oxidising agent. Cooper used perhydrol and sulphuricacid, followed by the molybdenuni- blue estimation, adding stannous chloridebefore the molybdate.W. R. G. Atkins and E. G. Wil-son ls suggested that the discrepancy between their results and those ofD.J. Matthews,6 when compared with the values obtained by E. Rabenon the phosphate content of sea water, were due to the fact that they usedDenigbs’s colorimetric method and Matthews used the method of L. Pougetand D. Chouchak,lg whilst Raben’s method involved evaporation withnitric acid. It is suggested that, as arsenic in sea water exists largely asarsenite, after oxidation (Raben) this would be included in the phosphate.Atkins and Wilson found that Pouget and Chouchak’s method gives animmediate opalescence in the cold (if dilute, on standing) with phosphates,opalescence only on warming with an arsenate, and with arsenite only itfaint opalescence on warming owing probably to oxidation to arsenate.They also showed that the Deniges reaction could be used for the deter-mination of arsenate, but only a faint colour was produced with arsenites,again probably owing to oxidation.N.W. Rakestraw- and F. B. Lutz 2O ‘used the Gutzeit method, and amodified Gutzeit method has been described 2 l which is essentially a modi-Arsenic (0.1-0.5 pg.-atom of As/l).Intern. Rev. ges. Hydrobiol., 1938, 37, 420.l6 J . Marine Biol. ASSOC., 1937, 21, 673.l8 J. Marine Biol. ASSOC., 1927, 14, 609.l@ Bull. SOC. chim., 1909, 5, 104; 1911, 9, 649.21 S. Gorgy, N. W. Rakestrrtw, and D. L. Fox, J . Marine Rea., 1948, 7, 22.1 7 Biol. Bull., 1937, ‘53, 421.2O Biol. Bull., 1933, 65, 397BARNES: ANALYSIS OF SEA WATER. 341fication of that due to M.B. Jacobs and J. Nayler.22 After reduction ofAs” by acid bisulphite, arsiiie was absorbed in sodium hypobromite andthen reduced by hydrazine sulphate in the presence of acid molybdate.Arsenic (0.5 pg.-atom/l.) present in the sea was fractionated into arsenite(50-60 yo), arsenate, dissolved organic arsenic, and particulate arsenic(each 8--16%).Silicates (0.0007-4-14 mg.-atom of Si/l.).-W. R. G. Atkins and E. G .Wilson introduced the method of F. Dienert and F. Wandenb~lcke,~~using picric acid standards for the comparison, and further study of thereaction has been made by T. G. Thompson and H. G. Houlton 24 (q.v. forearlier references). The original picric acid standards were shown to bein error and corrections have been made.25 The advantages of borax-buffered standards of potassium chromate 26 to replace picric acid havebeen stressed by R.J. Robinson and H. J. Spoor,27 who found that thefull colour development took place within 3 minutes and there was nofading within 2 hours. Temperature was found to be without effect.S. W. Brujewicz and L. K. Blinov’s results 28 on the effect of salt concen-tration were not confirmed ; they found a correction factor of 1-16 in con-trast to the Russian workers’ value of 1.66. Dienert and Wandenbulckefound that silica in the colloidal form is not determined by these reagents,but further investigations on this and upon the effect of salinity upon thecolour development cppear desirable.Nitrogen.-Ammonia (0.35-3.5 mg.-atom of NH,-N/l.). H. E. Wirthand R.J. Robinson 29 have compared the earlier methods 3O and found aJl thereagents except Treadwell’s to have a non-sensitive region. The sensitivityof Treadwell’s reagent increases with increasing chlorinity, but Beer’s lawdoes not apply a t low concentrations. A. Krogh31 used a vacuum-dis-tillation method after making the water alkaline, the liberated ammoniabeing absorbed in hydrobromic acid and determined by T. Teorell’s naphthyl-red t i t r a t i ~ n . ~ ~ Air a t reduced pressure is used to drive off ammonia, andattention must be paid to blank determinations, The accuracy of a singledetermination is of the order of 0.04 pg. of nitrogen (20-ml. sample). Themethod can be adapted for the determination of ammonia in air.22 I d . Eng.Chem. Anal., 1942, 14, 442 ; see also Ann. Reports, 1944, 41, 282.23 Compt. rend., 1923, 176, 1478.24 Ind. Eng. Chem. Anal., 1933, 5, 417.25 E. J. King, Conlr. Canal. Biol. and Pi.&., 1931,8,119 ; E. J. King and C. C. Lucas,J . Anzer. Chenz. SOC., 1928, 50, 2395; Robinson and Kemmerer, ref. 14, p. 129.26 H. W. Swank and M. G. Mellon, Ind. Eng. Chem. Anal., 1934, 6, 348.27 Ibid., 1936, 8, 455.28 Bull. State Oceanog. Inst. U.S.S.R., 1933, No. 14, 44.29 Ind. Eng. Chena. Anal., 1933, 5, 293.30 R. Witting, Oefv. Finska Vet.-Soc. Forh., 1915, 57, No. 21; H. Wattenberg,Cons. Perm. Intern. Rapp., 1929, 53, 90; Ann. Hydrog., 1931, 59, 95; T. Bramud andA. Klem, Hvalradets Skr., 1931, No. 1 ; L. H. N. Cooper, J . Marine Biol. ASSOC., 1933,18, 677 ; K.Buch, Merentutkimuslaitoksen Julkaisri. Havs. Skrift., 1920, 2.31 Bwl. Bull., 1934, 81, 126.92 Biochem. Z., 1932, 248, 246342 ANALYTIUAL OHEMISTRY.Nitrate (0.1-43.0 mg.-atom of N03/l.). The phenoldisulphonic acidmethod is not applicable in the presence of chloride. Reduction to ammoniahas been but the method is tedious and the results are open toquestion, since ammonia may be formed during reduction from nitrogenoussubstances. Two methods have been employed, both depending uponoxidation of a reagent in strong sulphuric acid with the production ofcoloured compounds. W. R. G. Atkinsa proposed the use of diphenyl-benzidine, but H. W. Harvey’s reduced strychnine reagent 85 is more com-monly employed; directions are given for preparing the reagent, theproperties of which are somewhat capricious.The presence of much dis-solved or particulate organic matter vitiates the results. Difficulties werereported by T. G. Thompson and M. W. J0hnson,3~ but L. H. N. Cooper:’using safranine as an artificial standard, found the method satisfactory,although erratic results were obtained in the presence of nitrites. B. M. G.Zwicker and R. J. Robinson38 confirmed by analysis that strychnidine andtetrahydrostrychnine were the main products in the reduction employedby Harvey and they suggest the use of strychnidine (which gives a moreintense absorption maximum) prepared by electrolytic reduction of strych-nine in sulphuric acid solution using a mercury cathode.3B Data are givenconcerning the effect of reagent concentration on the colour produced withthis strychnidine reagent.Distrychnidyl, although difficult to prepare anduse, is twice as sensitive as the strychnidine reagent. Purther details ofthe preparation of a satisfactory reagent and of its behaviour are given byW. A. Ridde140 and D. Rochford,4l who recommend addition of hydro-chloric acid to increase the sensitivity.(4.v. for earlier work) has determined the necessaryconditions for the use of E. A. Letts and P. W. Rea’s diphenylbenzidinereagent.42 Nitrites give erratic results. In view of the fact that it hasbeen reported that the Harvey reagent and diphenylbenzidine reagentdiffer little in sensitivity, the neglect of the latter would hardly seemjustified .The dissolvednitrogen in lake waters has been determined and fractionated into a numberof components, samples obtained by evaporation of large quantities ofwater being used.& Amino- and non-amino-nitrogen were determined, butW.R. G. AtkinsDissoEved organic nitrogen (0.1-10.0 mg.-atom of N/l.).33 E. Raben, Wiss. Meeresunters., 1905, 8, 81; 1910, 11, 303; 1914, 16, 207.34 J . Marine Biol. Assoc., 1932, 18, 167.35 Ibid., 1926, 14, 71; 1928, 15, 183.36 Publ. Puget Sound Biol. Station, 1929, 7, 345.37 J . Marine Biol. ASSOC., 1932, 18, 161. 38 J . Marine Res., 1944, 5, 214.B. M. G. Zwicker and R. J. Robinson, J . Amer. Chem. SOC., 1942,64, 790.J . Biol. Bd. C a d . , 1936, 2, 1.*l Commonwealth of Australia, C.B.I.R., Bull. No. 220, 1947.4a J., 1914, 105, 1157.43 B.P. Domogalla, C. Juday, a d W. H. Peterson, J . Biol. Chem., 1925, 63, 269;W. H. Peterson, E. B. Fred, and B. P. Domogalla, ibid., p. 287 ; E. A. Birge and C. Juday,Bull. Bur. Pkheries, 1926, 42, 185; E. A. Birge and C. Juday, Proc. Nat. Acad. Sci.,1926, 12, 515BARNES: ANALYSIS OF SEA WATER. 348it is not certain that no decomposition had taken place during evaporation.The albuminoid and total nitrogen of water of the Puget Sound have beeninvestigated by R. J. Robinson and H. E. Wirth,44 using standard methodsof analysis and large volumes of water. in develop-ing a method for smaller quantities of water, abandoned Kjeldahl methodssince ammonia was always obtained in amounts from 0.5 to 2 vg. of nitrogenper ml. on heating sulphuric acid, and all efforts to remove this " organic N "failed.Their method (sensitivity approximately 0.3 pg. of N) involves diges-tion of the sample at 500" with sodium hydroxide in a silver tube in anatmosphere of hydrogen. The ammonia formed is then taken up in ~ / 1 0 0 -hydrobromic acid, combined with sodium hypobromite and the excesshypobromite titrated according to Teorell's method (see p. 341). Detailsare given for purification of the hydrogen, setting up the apparatus, andpreparation of distilled water free from organic nitrogen. T. von Brandand N. W. Rake~traw,~~ using the method, showed that the error is usuallybelow 10% in samples containing approximately 200 pg. /litre of dissolvedorganic nitrogen.Cwbon,--DissoZced and particulate carbon ( 0 .1 4 - 4 mg.-atom of C/l.).A number of methods involving alkaline permanganate have been used todetermine the dissolved organic matter, but none can be considered verysati~factory.~~ A. Krogh and A. Keys45 developed a wet combustiontechnique similar to that of H. Lieb and H. G. Krainich,4* the methodinvolving the removal of salts. After expulsion of carbon dioxide by boil-ing, most of the chloride is precipitated by thallium sulphate, and afterevaporation, the dry residue is oxidised with a mixture of chromic andsulphuric acids in a current of carefully washed air. The carbon dioxideand carbon monoxide are carried through an oxidising combustion tubeinto baryta, the excess of which is titrated with hydrochloric acid. 25 MI.of water are used and careful attention to blanks is emphasised. Theaccuracy approaches 0.1 mg. of carbon/l. but the blank is rather high.By using filters, colloidal, soluble, and particulate carbon were differentiated.Trace Metals.-Zinc can be determined with d i t h i ~ o n e , ~ ~ but beforedetermination af manganese (as perrnanganate) 50 or iron (as the thiocyanatecomplex) 51 halides and organic matter must be removed completely.N. W. Rakestraw, H. E. Mahncke, and E. F. Beach 5z first concentrate theA. Krogh and A.44 J . du Cons., 1934, 9, 15, 187.46 J . Marine Res., 1941, 4, 76.47 W. R. G. Atkins, J . Marine Biol. ASSOC., 1922, 12, 772; 1923, 13, 160; G. J.Pereira, Bol. de Pescas, 1924, 9, 149; W. E. Adeney and B. B. Dawson, Sci. Proc.Roy. Dublin Soc., 1926, 18, No. 17; 0. G. Ibanez, hTotas y Resurnenes, 1928, 11, No. 26;P. Chauchard, Compt. rend., 1932, 194, 1256; Ann. Inst. Oceanog., 1935, 15, 329.48 Mikrochem., 1931, 3, 367.49 K. Buch, Finska Kern. Medd., 1944, Nos. 1-2, 25.61 T. G. Thompson and R. W. Bremner, J . du Cons., 1935,10,39; T. G. Thompson,62 Ibid., 1936, 8, 136.45 Biol. Bull., 1934, 67, 133.T. G. Thompson and T. L. Wilson, J . Amer. Chem. Soc., 1935, 57, 233.R. W. Bremner, and I. M. Jamieson, Ind. Eng. Chem. Anal., 1932, 4, 288344 ANGPTIOAL CHEMISTRY.iron in sea water by precipitation and reduction with ammonium sulphide,the co-precipitated basic magnesium salts acting as excellent carriers.Fluoride did not interfere with the recovery of 0.01-0-04 mg.11. Theauthors noted that ethylene glycol monobutyl ether had a stabilisinginfluence on the red thiocyanate complex which they extracted with amylalcohol: since it was stable to light but not to heat it was necessary tocontrol the temperature before extraction.2 : 2’-Dipyridyl and 2 : 2’ : 2”-tripyridyl53 were introduced into seawater analysis by L. H. N. Cooper,M and a careful study of the reactionbetween dipyridyl and iron a t high dilutions of the latter by K. Buch 55emphasises some of the dficulties likely to be encountered. Thus accord-ing to Cooper and J. H. Boxendale and P. George 56 only undissociateddipyridyl ( K , = 1-2 x molecules enter the complex, sothat both pH, neutral salts, and concentration of reagents affect the reaction.Theoretical calculations using data obtained by L. H. N. Cooper 57 andby P. A. Kriukov and G. P. Awesjewitsch 58 are given by Buch.Copper has been determined by sodium diethyldithiocarbamate. 59 H.Barnes 6O has given methods for the determination of copper and mercuryin sea water solutions in connection with anti-fouling investigations. Otherworkers on this problem have discussed the copper content of marineorganisms and sea water and the relationship to Since the workof H. 3’. Prytherch62 attention has been paid to the copper content ofoysters and sea water under natural and artificial conditions. G. A. Riley 63has used the carbamate reagent with estuarine waters, and K. Buch49gives a dithizone method in a paper which includes useful data on theextraction of copper and zinc dithizonates by different solvents at varyingpH values of the solution.K, -H. B.H. BARNES.H. R. CLAYTON.H. IRVING.L. LEYTON.53 Ann. Reports, 1945, 42, 258.66 Fin-ska Kem. Me&., 1942, 51, 22.s7 Proc. Roy. SOC., 1937, B, 124, 299.6s W. R. G. Atkins, J . Marine BioZ. ASSOC., 1932, 18, 193; 1933, 19, 63.6o Ibid., 1946, 26, 303.61 G. L. Clarke, Bwl. Bull., 1947, 92, 73; C. M. Weiss, ibid., 1947, 93, 56.62 Ecol. Monographs, 1934, 4, 47.03 J . Marine Res., 1937, 1, 60.54 Proc. Roy. SOC., 1935, B, 118, 419.56 Nature, 1948, 162, 777.2. Electrochem., 1933, 39, 884

ISSN:0365-6217    

DOI:10.1039/AR9484500316

出版商:RSC    

年代:1948

数据来源: RSC

摘要:

INDEX OF ATJTHORS’ NAMES.Abel, J. J., 283.Ablondi, F., 222.Abraham, E. P., 207, 208.Abrams, R., 249.Ackroyd, H., 245.Acree, F., 164, 167, 169,Adam, N. I<., 34.Adams, R., 35, 201, 211,Adams, R. E., 142.Adell, B., 113.Adeney, W. E., 343.Adkins, H., 134, 136, 199,Aepli, 0. T., 278.Agar, J., 219.Aggarwal, S. L., 111.Ainley, A. D., 92.Ajl, S. J., 266.Akulov, N. S., 81.Albert, P., 86.,4lbertson, N. F., 131.Alcalay, W., 312.Aldrich, L. T., 85.Alexa, V., 330.Alexander, A. E., 42.Alexander, E. R., 130.Allen, A. O., 8, 17, 24, 52.Allsopp, A., 278.Allsopp, C. B., 23.Alper, T., 25, 31.Altman, K. I., 254, 256,Alyee, H. N., 21, 23, 68.&4melin, A. G., 107.Aininoff, D., 274, 281.Amphlett, C. B., 116.Amstein, E. H., 321.Andersen, H.C., 65.Anderson, A. B., 189.Anderson, 8. L., 16.Anderson, H. H., 97.Anderson, R. B., 60.Anderson, R. C., 233.Anderson, R. J., 292, 295,297, 298, 299, 302, 311.Anderson, T., 306.Andersson, K. J. I., 284.Anfinsen, C. B., 241.Angelescu, E., 42, 43.Angier, R. B., 226, 227, 230,231, 233, 237.Anker, H. S., 241.Anouar, &I., 90.Anslow, W. P., jun., 221.Apin, A. J., 101.Appel, W., 105.170.314.200.265.Appleby, W. G., 60.Appleyard, R. K., 8.Arbusov, B. A., 128, 177.Archer, S., 131.Arden, T. V., 84, 271.Arens, J. F., 204.Aristoff, E. E., 137.Armstrong, (Miss) G. P.Armstrong, M. D., 221.Armstrong, W. D., 254, 267.Arnell, J. C., 60.Arnstein, H. R. V., 192.Aronson, J. D., 299.Arth, C.E., 223, 233.Arthur, J. R., 95.Artsdalen, E. R. van, 64,Arvidson, H., 246.Ashmore, P. G., 74.Ashworth, R. de B., 206.Atherton, F. R., 138.Atkins, W. R. G., 333, 340,341, 342, 343, 344.Atkinson, H. F., 272.Attoe, 0. J., 329.Auclair, J. L., 274, 278.Audrieth, L. F., 331.Avakian, S., 212.Avanoff, S., 113.Avery, 0. T., 298, 299.Avery, W. H., 60.Avramenko, L. L., 76.Awesjewitsch, G. P., 344.Aynsley, E. E., 105.Babson, R. D., 219.Bachmann, G. B., 125.Bachmann, W. E., 137,208,Backer, H. J., 236.Backes, M., 207.Bacon, R. G. R., 176, 177.Baddiley, J., 138, 208.Badger, G. M., 136.Badin, E. J., 77.Baer, E., 169.Baget, J., 105.Bagge, E., 13.Baggenstoss, A. H., 293.Baggesgaard-Rasmussen,Bahr, G., 107.Bailar, J.C., 113.Bailar, J. C., jun., 107.Bailes, R. H., 84, 113.Bair, R. K., 137.Baird, W. S., 319.136.65.209.H., 336.345Baker, B. R., 220, 221, 222,Baker, L. E., 10.Baker, P. B., 272, 273, 282.Baker, W., 187, 207, 208.Baker, W. E., 123.Bddwin, E., 271, 277.Bale, W. F., 259.Balfour, W. M., 259.Balz, G., 318, 319, 322.Barnziger, N. C., 116.Bandel, G., 335.Bandler, M., 105.Banerjee, P. C., 83.Banks, C. K., 332.Bardeen, J., 86.Bardishev, I. I., 174.Bardwell, D. C., 21, 22.Barkelew, C. H., 113.Barker, B. I., 294.Barker, F. G., 326.Barker, H. A., 244, 252,Barker, R. L., 176, 178.Barltrop, J. A., 189.Barnes, F. W., 245.Barnes, H., 344.Barnes, R. A., 156.Barnes, R. B., 328, 330.Barrer, R. M., 61, 96.Barron, E.S. G., 262.Barrowcliff, M., 314.Barry, V. C., 312, 314.Barthel, W. F., 164, 165,. 166, 167, 169, 170, 173.Bartlett, P. D., 143, 145,Barton, D. €1. R., 60, 149,Barton, N., 193, 198.Bartz, J. R., 308.Bmolo, F., 113.Bassett, H., 82.Bastiansen, O., 183.Bateman, L., 114.Bates, R. W., 285.Baudisch, O., 137.Baudouin, A., 331.Bauer, R., 319.Bauer, S. H., 92.Baumeister, L., 23.Bavel, T. van, 134.Bawn, C. E. H., 23, 51.Baxendale, J. H., 159, 344.Baxter, R. A,, 122, 214.Beach, E. F., 343.Beachell, H. C., 157.Beck, M., 110.223, 224.260.147.183, 184346 INDEX OF AUTHORS’ NAMES.Becker, W. W., 333.Becquerel, J., 5.Beerwald, A., 319.Behrens, 0. K., 212, 214.Belcher, R., 333.Beljakov, M. I., 107.Bell, D.J., 277.Bell, F., 196.Bell, G. H., 295.Bell, R. N., 101.Beloff, A., 241.Belt, M., 227.Belton, J. G., 312.BBnard, J., 86.Bender, H., 59.Bendich, A., 205, 246.Bendigo, B. B., 169.Bened&ti-Pichler, A. A.,Benesi, H. A., 109.Benians, T. H. C., 299.Benkeser, R. A., 219.Benson, A. A., 276.Bentley, R., 208, 260, 261.Bergel, F., 207.Berger, F., 340.Berghe, J. van den, 211.Bergman, W. E., 101.Bergmann, E., 138.Bergmm, E. D., 132.Bergmann, F., 151.Bergstrand, H., 325.Bergstrom, S., 246.Berman, L., 215.Berman, S. M., 332.Bernal, J. D., 46.Bbrnard, J. B., 112.Bernheim, F., 306, 309.Bernold, E., 186.Bernstein, S., 202, 221, 222,Bernthsen, A., 207, 212.Berry, A. J., 331.Berry, J. W., 328, 330.Berry, T.M., 322.Berthelot, A., 310.Besson, J., 112.Bethe, H., 10.Beucker, H., 158.Bevington, J. C., 101.Bhattacharya., B. K., 182.Billen, G. N., 135.Billics, H. R., 199.Bingley, J. B., 108.Birch, A. J., 99.Birckenbach, L., 101.Birge, E. A., 342.Birkinshaw, J. H., 188.Bishop, W. B. S., 22.Bitskei, J., 332.Blackburn, S., 276, 278.Blair, V. E., 251.Blanchard, M. H., 288.Blass, J., 272.Blicke, F. F., 206.Blinov, L. K., 341.334.223.Bloch, F., 10, 14.Bloch, I., 213.Bloch, K., 240, 241, 245,253, 262, 263, 297.Block, R. J., 274, 275, 280.Blocker, J. M., jun., 98.Blomquist, A. T., 127.Bloom, E. S., 229.Bloom, H., 87.Blumberg, E. A., 59.Blumrich, K., 335.Bodart, J., 16.Bode, H., 102.Bodenstein, M., 54, 55, 65.Boekenoogen, H.A., 207.Boeseken, J., 141.Boeters, O., 137.Boettner, E. A., 323.Bogdandy, S. von, 69.Bohme, H., 105.Bohonos, N., 229.Bohr, N., 10.Boissevttin, C. H., 297.Boldingh, J., 270, 282,Bolman, 0. E. A, 38.Bolz, A., 93.Bond, A. C., 122.Bondi, A., 138.Bonet-Maury, P., 6, 23, 24.Bonhoeffer, K., 16.Bonso, O., 127.Boon, S. D., 327.Boon, W. R., 277.Booth, H. S., 102, 109,116.Boothe, J. H., 226, 227,230, 231, 233, 237.Boquet, A., 300, 301.Boratynski, K., 328.Bordwell, F. G., 137.Bornstein, B. T., 260.Borsche, W., 196.Borsook, H., 276.Boscott, R. J., 270.Bosworth, R. C. L., 99.Botty, M. C., 275.Bouckaert, J. P., 283.Bougault, J., 198.BoullB, A., 101.Bourquin, J. P., 200.Bowden, K., 134.Bowman, R.E., 129.Braarud, T., 341.Brackebusch, H., 319.Bradbury, N. E., 14.Brady, A. P., 38.Bragg, Sir W., 11.Bradey, G. E. A., 317.Branchen, L. E., 336.Brand, E., 268, 286, 287.Brand, T. von, 343.Brandt, C. W., 180, 182.Brasseur, P., 112.Brattain, K. G., 19.Brattain, W. H., 86.Braudo, C., 322.Brauer, G., 103.Brauer, W., 319.Braun, J. von, 198.Bray, J. M., 325.Braz, G. I., 218.Breckenridge, J. G., 88Brederode, H. V., 96.Breger, I. A., 6.Brehm, W. J., 202.Breit, J. E., 332.Breitweiser, W., 327.Bremner, R. W., 343.Brennan, E. A., 176, 177.Brenneisen, E . , 2 17.Bretey, J., 310.Bretschger, M. E., 104.Brewer, A. K., 91.Brewington, G. P., 323.Brigando, (Mlle.) J., 113.Briggs, F., 196.Brink, N.G., 202, 308.Brintzinger, H., 85.Briscoe, H. V. A., 92.Brocard, J., 90.Broda, E., 23.Brode, W. R., 316, 325.Brodersen, P. H., 109.Brodrick, C. I., 207, 210,Brody, J. K., 325.Broglin, J., 98.Brommelle, N. S., 319.Brosset, C., 108.Brouns, R. J., 113.Brown, D. J., 145.Brown, F., 273, 298.Brown, F. B., 54, 55.Brown, G. B., 205, 221, 246,Brown, H. A., 308.Brown, H. C., 93.Brown, J. B., 112.Brown, R., 130.Brown, R. H., 335.Brown, R. K., 158.Brown, W. G., 122.Brown, W. W., 319.Brownlee, G., 233, 300, 302,Brownscombe, F. R., 24.Brujewicz, S. W., 341.Bruni, G., 213.Brunstetter, B. C., 325.Brus, G., 174.Bmon, H. A., 124, 125.Brutschy, F. J., 200.Bruun, T., 180.Bryan, F. R., 323.Buch, K., 341, 343, 344.Buchanan, G.L., 193, 198.Buchanan, J. M., 247.Buchheit, P., 93.Buchholz, E., 102.Buchman, E. R., 156, 214.Buchi, G., 176, 186.Buchi, J., 309.Buehler, C. A., 136.250, 251.304, 306INDEX OF AUTHORS’ NAMES. 347Bugge, G., 213.Bugie, E., 307,Bullock, J. K., 294.Bunton, C. A., 149.Burcham, W. E., 16.Burgener, J. E., 317.Burke, H. E., 294.Burns, W., 116.Bursian, K., 191.Burstall, F. H., 84,Burton, C. J., 275.Burton, M., 10, 17, 52.Burton, V. L., 6.Bury, C. R., 50.Bustinza, F., 312.Buston, H. W., 313.Butler, G. C., 301.Butler, J. A. V., 289.Butler, S. M. J., 331.Buttle, G. A. H., 305.Butts, P. G., 333.Buyanov, N. V., 317.ByB, J., 108.Byers, L. W., 309.283.271,Cady, G. H., 86, 109.Caillat, R., 96.Caillot, T., 24.Cain, C.K., 233, 234, 236.Cairns, T. L., 217.Calam, C. T., 277.Caldecourt, V. J., 319, 322,Calfee, R, K., 330.Calhoun, G. M., 55.Calker, J. van, 317, 325.Callen, J. E., 218.Calloman, F. T., 305, 306.Callon, R, W., 317.Callow, R. K., 309.Calmette, A., 300.Calmont, P., 19.Calvin,M., 84,113, 212,276.Cameron, A. T., 7.Campaigne, E., 201, 211.Campbell, A. N., 88.Campbell, B. K., 217, 218.Campbell, I. E., 98.Campbell, I. G. M., 172.Campbell, K. N., 217, 218.Campbell, N., 216.Campbell, W. P., 176, 180,Capron, P. C., 6, 19, 20.Caraway, K, P., 333.Cardon, B. P., 244.Carless, C, M., 318.Carlsson, C. G., 325.Carmack, M., 211, 212.Carmody, W. R., 331.Carphi, G., 97, 108.Carr, D. T., 308.Carr, F.H., 291.Carrihe, E., 86, 87, 90, 91,323.181, 182.94, 103.Carter, H. E., 300.Casarett, G. W., 254.Cass, W. E., 143, 145.Catch, J. R., 130, 208, 269,Cattelain, E., 198.Cauchois, (Mlle.) Y., 107.Caughlan, J. A., 219.Cavalca, L., 89, 90.Cavalieri, L. F., 251.Cecconi, R., 89.Ceithaml, J., 267.Cerenkov, P. A., 16.Chabrier, P., 199.Cheiet, L., 231.Chain, E., 207, 208.Chamberlin, E. M., 142.Chambers, A. R., 188.Chantrenne, H., 242.Chapman, N. B., 138.Chappell, D. G., 330.Chaput, E. P., 217.Chard, S. J., 136.Chargaff, E., 250, 274, 276,Charles, A. F., 290.Charpy, A,, 313.Chattaway, F. W., 226.Chatterjee, R., 216.Chauchard, P., 343.Chaudron, G., 112.Chemerda, J. M., 137.Chenicek, J. A., 159.Cherbuliez, E., 128.Chibnall, A.C., 284, 287.Cliolak, J., 321, 325.Choppin, A. R., 60.Chorine, V., 310.Chouchak, D., 340.Chow, B. F., 289.Chrbtien, A., 89, 98, 110.Christ, C. L., 275.Christiansen, J., 41.Christine, 0. W., 317.Churchill, H. V,, 320.Churchill, J. R., 320, 325,Ciapetta, F. G., 331.Cirilli, V., 90.Claesson, S., 269,Clapp, L. B., 218.Clapper, W. E., 260.Clark, R, H., 125,Clarke, B. L., 324.Clarke, G. L., 344.Clarke, H. T., 200.Clay, A. C., 306.Clay, M. G., 306.Clayton, H. R., 318, 319,Clemo, G. R., 178.Cloetens, R., 19, 21.Clough, G. W., 199.Clusius, K., 97, 110.Clutton, R. F., 301.Coates, A. C., 321.Cockburn, R., 278.275, 277.281.322, 326.C o f i , C, C., 60.Coghill, 298.Cohen, A., 192, 194.Cohen, P., 317.Cohen, P.P., 242, 252.Cohn, E. J., 288.Cole, Q. F., 205,Coleman, A. L., 218.Coleman, G. H., 212, 314.Coleman, P. D., 328.Collins, C. B., 92.Collins, G. B,, 16.Collins, H. L., 317.Collinson, E., 27, 31.Collit, G. B., 302.Colman, G. H., 35.Colwell, 30.Compere, E. L., 60,Conalty, M. L., 312.Conant, J. B., 335.Condike, G. F., 93.Condon, E. U., 14.Conn, J. B., 231.Conrad, N., 132.Conroy, H. W., 331.Consden, R., 268, 270, 272,273, 274, 276, 278, 279,283.Controulis, J., 308.Convey, J., 326.Cook, A. H., 130, 200, 206,207, 208, 209, 214, 216,269, 277.Cook, J. W., 136, 192, 193,194, 195, 196, 198.Cook, R. P., 105, 314.Cook, W. B., 159.Cookson, R. C., 126.Coolidge, W. D,, 7.Cooper, F. S , , 7.Cooper, H., 304.Cooper, L.H. N., 339, 340,341, 342, 344.Corner, E. S., 57.Cornu, A., 317.Correll, H., 317.Corriez, P., 102,Corrin, M. L., 38, 42, 44,Corse, J. W., 212.Corte, H., 85.Cory, J. C., 97.Cosulich, D. B., 226, 227,Cottin, M., 104.Cottle, D. L., 106.Coulthard, C. E., 297, 298.Cowley, J. M., 98.Cox, E. G., 106.Cox, R. F. B., 178.Craig, L. C., 279.Crammer, J. L., 274, 282.Cranshaw, T. E., 116.Crawford, B. L., 114.Crawford, M., 87.47.233.Courty, c., 99348 INDEX ox AUTHORS’ NAMES.Creighton, M. M., 297.Criegee, R., 158, 198.Crist, R. H., 52, 54, 55.Crombie, L., 169, 171, 173,Cromwell, N. H., 219, 220.Cronheim, G., 137.Crooks, H. M., 308.Crosbie, A. W., 136.Crossley, F.S., 129.Crosswhite, H. M., 323, 324.Crounse, N. N., 219.Crovath, A. M., 14.Crowder, J. A., 311.Crowfoot, D., 284.Croxton, F. C., 116.Cruickshank, D. B., 91.Crumpler, H. R., 275.Cruz, W. O., 259.Cueillon, J., 83, 86.Culhane, K., 291.Cullinane, N. M., 136.Cullis, C. F., 69, 74.Cultrera, R., 99.Cunneen, J. I., 154.Cunningham, G. L., 332.Curd, F. H. S., 215.Cnthbertson, W. F. J.,Czarnetzky, E. J., 294.Dacey, J. R., 60.Dainton, F. S., 8, 10, 14,16, 18, 24, 27, 30, 31,69, 74, 77, 101, 159.Daizins, E., 310.Dakin, H. D., 131.Dale, W. M., 25.Dam, H., 311.Danders, C., 97.Daniel, L. J., 233.Daniels, F., 55, 56.Dannley, R. L., 141.Darmon, S. E., 276, 287.Darzens, G., 123.Datar, D. S., 107.Dauben, H.J., jun., 169.Dauben, W. G., 142, 212.Daudel, R., 110.Daunt, J. G., 85.Davidson, A. E., 110, 111.Davidson, J. N., 278.Davidson, N., 13.Davidson, W. M., 165.Davies, D. G., 50.Davies, G. R., 84, 271, 283.Davies, W. D., 127.Davis, A. K., 329.Davis, C. H., 211.Davis, L. W., 98.Davis, T. W., 52.Davoud, J. G., 58.Dawes, E. A., 279.Dawson, B. B., 343.Dawson, I. M., 105.Dawson, J., 279.Deal, E. C., 332.275, 282.Dean, IS. F., 189.Dean, P. M., 212.Deasy, C. L., 276.De Boer, H., 103.De Boer, J. H., 88.De Duve, C., 283.Dehn, W. M., 189.Deinnes, L., 299.Delluva, A. M., 247, 267.Delwaulle, (Mlle.) M. L.,De Mende, S., 91.Dement, J., 82.Demers, P., 116.Dent, C. E., 268, 273, 274,Dsrvichian, D. G., 45, 46,Desch, C.H., 84.DeTar, D. F., 154,211,212.De Vault, D., 268.Devos, C., 22.De Walt, C. W., 202.Dewar, M. J. S., 103, 114,Dewing, T., 305.DeWitt, T. W., 101.Dexter, S., 324.Dhingra, D. R., 155.Diamond, L. K., 233.Dick, A. T., 108.Dickens, F., 260.Dickenson, L., 297, 298.Dickson, G. T., 195, 196,Diczfalusy, E., 307.Diehl, H., 113.Dieke, G. H., 323, 324.DiBnert, F., 341.Dietert, H. W., 319, 320,322, 323, 326.Di Fonzo, M., 307.Dirscherl, W., 290.Dittrich, C. W., 101.Djerassi, C., 156.Doak, G. O., 102.Doan, C. A., 292, 297, 298.Dobriner, K., 257.Dobson, I?., 272, 273, 282.Dodds, E. C., 289.Dodonov, J. J., 97.Dolby, D. E., 226.Dormgk, G., 305.Domange, L., 109.Domin6-Berg&, (Mme.) M.,Domingo, W. R., 328.Domogalla, B.P., 342.Donohus, J., 105.Donovick, R., 308.Dorfman, A., 262.Dorfman, E., 156.Dorfmann, L., 202, 223.Dorp, D. A. van, 204.Doumt, Y., 108.Dowling, G. B., 313.102.275, 278, 219, 282.49.187, 192.198.101.Drake, B., 272.Drake, H. C., 82.Drake, N. L., 198.Drew, R., 278.Drum, J. G. F., 82.Drucker, B., 278.Duane, W., 21, 23.Dubnikov, L. M., 109.Dubois, J. E., 124.Dubois, S., 103, 109.Dubos, R. J., 303, 304.Du Brow, P. L., 37.Duca, C. J., 310.Ducret, L., 103.Dudley, H. W., 295.Durst, O., 176, 186.Dufay, J., 94.Duffield, R. B., 84.Dufraisse, C., 105.Duggar, B. M., 5.Duguet, R., 87.Duke, F. R., 333.Dunkin, G. W., 311.Dunstan, W. J., 157.Du Pont, A., 135.Durand, R., 44.Dustin, P., 190.Du Vigneaud, V., 199, 209,214, 252, 283, 285, 286,290.Dwyer, F.J. P., 113, 115.Dyke, H. B. van, 289.Eager, R. L., 110.Eakin, R. E., 233, 250.Eastcott, E. V., 313.Eastmond, E. J., 318.Eble, T. E., 277.Echols, L. S., 59.Ecker, E. E., 301.Eddy, C. A., 285.Edens, C. O., 297.Edison, A. O., 308.Edman, P., 278.Edsall, J. T., 268, 291.Edwards, J. W., 239.Egsn, E. P., jun., 99.Egerton, (Sir) A. C., 77,104.Eggenberger, D. N., 37.Ehmann, L., 156.Ehrensvard, G. C. H., 213,Ehrlich, J., 331.Ehrlich, P., 89.Eichel, H., 290.Eidinoff, M. L., 86.Eigen, E., 274, 275, 282.Eimti, 0. J., 190.243.Elge, G. von, 67, 68, 69, 70,Elev. D. D., 61.71, 72, 73, 74, 78, 77.Eli&on, N: A., 246.Elion, G. B., 234.Elks, J., 215.Elledge, B.E., 325.Elliot, D. F., 208INDEX OF AUTHORS’ NAMES. 349Elliot, J. H., 336.Elliott, M., 166, 169, 173.Elliott, N., 116.Elliott,, R. C., 269.Ellis, D., 195.Ells, V. R., 324.Elmore, K. L., 94.Elsden, S. R., 252, 277.Elson, L. A., 92.Eltenton, G. C., 61.Elvidge, J. A., 207,208,209.Xmanuel, N. M., 77, 79, 80.EmelBus, H. J., 60, 96.Emerson, W. S., 159.Emmart, E. W., 306, 310.Englis, D. T., 319.English, A. C., 116.English, J., 135.English, J. P., 205.Engstrom, A., 275.Engstrom, R. W., 323.Ensslin, F., 94.Epstein, J., 337.Epstein, S., 85.Eriimetsl, O., 88, 91.Erbacher, O., 110.%rchak, M., jun., 90.Erden, B., 235.Erdtman, H., 189.Erickson, A. E., 236.Erickson, P. T., 314.Erlenmeyer, H., 205, 307.Errera, M., 256.Escolar, J.G., 331.Emex, H., 15, 19.Eucken, A., 103.Evans, D. P., 337.Evans, E. A., 252, 265, 288.Evans, M. G., 30, 61, 106,Evans, T. W., 149, 189.Evans, W. C., 278.Evenson, 0. L., 333.Everett, A. J., 149.Evers, E. C., 38.Ewens, R. V. G., 82, 83.Ewing, D. T., 325.Ewing, F. J., 84.Eyer, H., 290.Eyring, H., 20, 21, 22, 63.Faget, G. H., 314.Fahrenbsch, M. J., 226,Fairbrother, F., 111.Falkovsky, V. B., 58.Fanelli, R., 104.Fankuch, I., 90.Fano, U., 13.Fanta, P. E., 194, 198.Faraday Society, 114, 139.Farber, G., 97.Farber, S., 233.Farkm, A., 20.Farkm, L., 77.Farmer, E. H., 149,201.159.227.Farmer, T. H., 279.Farnworth, A. J., 157.Farrington, P. S., 334.Fame, P., 94.Feather, N., 83.Feenberg, E., 19.Fehhr, F., 105.Feigl, F., 85, 94.Feitknecht, W., 91.Feldman, W.H., 293, 303,305, 306, 307, 308, 310.Fellows, C. H., 22.Felton, L. D., 299.Fentress, J., 94.Fernelius, W. C., 82.Fernholz, H., 196.Ferrari, A., 89, 90.Ferrel, R. E., 291.Ferry, J. D., 288.Feussner, O., 322.Field, M. C., 37.Fieldes, M., 320.Fieser, L. F., 142, 176, 180,Fildes, P., 302.Fill, M. A., 333, 334.Finholt, A. E., 122.Fink, E., 255.Fink, K., 275.Fink, R. M., 276.Finlre, W. W., 83.Finland, M., 309.Fischback, H., 277.Fischer, E., 280.Fischer, H., 255.Fischer, W., 98.Fishel, W. P., 111.Fisher, A. M., 288, 290.Fisher, E., 88.Fisher, F., 153.Fisher, R. B., 280.Fitch, A., 290.Fitz, E. J., 320.Fitzgerald, R.J., 309.Flatt, R., 333.Fleck, E. E., 174, 176, 177,178, 179.Fleming, R. H., 338.Fleming, T., 332.Fletcher, C. J. M., 52.Fletcher, H. G., jun., 203.Flood, A. E., 281.Florcy, K., 268.Flynn, E. H., 202.Foex, M., 115.Folch, J., 313.Folkers, K., 124, 199, 200,202, 214, 223, 233, 308.Folkins, H. O., 58.Folmer, H., 6.Fones, W. S., 128.Fonken, G. S., 199.Forbes, G. S.. 97.Foreman, E. M., 274.Forkner, C. E., 297, 298.Forrest, H. S., 228, 236.182.ForsBn, L., 89.Forsyth, J. S. A., 59.Porsyth, W. G. C., 274, 281.Foster, G. E., 305.Foster, J. W., 231.Fouasson, F., 106, 107.Fowler, R. H., 56.Fox, C. L., 250.Fox, D. L., 340.Fox, G. W., 324.Fox, R. E., 14.Fraenkel-Conrat, H., 283,Francis, J., 311.Franck, J., 17, 85.Franqois, F., 102.Frank, F.C., 83.Frank, H. R., 194, 198.Frank-Kamenetsky, A. A.,Frank-Kamenetsky, D. A.,Franklin, A. L., 227.Fred, E. B., 342.Freeman, H. W., 82.Freiman, M., 152.French, D., 291.Freudenberg, K., 290.Freund, H., 98.Freund, R., 300.Freundlich, H., 41.Frey, (Mme.) H., 108.Frey, J. M., 174.Fricke, H., 23, 24, 25, 30.Friedberg, F., 242.Friedheim, G., 110.Friedmann, R., 302.Frisch, P., 105.Frost, A. A, 68.Frost, B. M., 308.Frudley, T. W., 135.Fuchs, C. F., 154, 160.Fiirth, R., 319.Fugassi, P., 60, 63.Fujitani, J., 163, 172.Fukuri, G., 180.Fuller, A. T., 291.Funk, H., 85.291.81.59.Gabriel, S., 218.Gall, J. F., 278.Gallagher, T. F., 283.Gallais, F., 87, 88.Gallin, (MlIe.) G., 99.Galmiche, P., 110.Gardner, L.U., 293.Gardner, T. S., 216.GBrkuscha, G. A., 174.Garlet, R., 99.Garner, C. S., 82.Garner, W. E., 19.Garrett, A, B., 116.Garrett, H. E., 39.Garrison, W. M., 23.Garstrtng, W. L., 69.Garvey, B. S., 168I N D ~ X OF AUTBORS’ NAMES.Gaskin, J. G. N., 89.Gatewood, E. S., 207.Gatterer, A., 319.Gaudin, O., 165.Gaudry, R., 126, 279.Gaydon, A. G., 76.Gazzola, A. L., 231.Gedye, G. R., 19.Gee, E. A., 98.Geiling, E. M. K., 285.Gelat, A., 131, 132.Gelber, W., 91.Gelissen, H., 141.Geller, R. F., 99.Genger, L. G., 297.George, P., 59, 344.Gerbault, (Mlle.) M.,Gerbes. W.. 12.90, 91.87,Gerding, H:, 96, 104.Gergely, J., 106.Gerlogh, T. D., 285.Gersdorff, W.A., 165, 171,Gesser, F., 106.Getler, H., 250.Getz, C. A., 332.Ghiorso, A., 116.Gibson, N. A., 113.Giella, M., 131.Giesecke, F., 327.Gilbert, H. N., 86.Gillam, A. E., 165, 167, 172.Gillerot, R., 19.Gilman, H., 212, 219.Gimingham, C. T., 173.Gingras, R., 279.Ginsberg, A., 136.Ginsberg, H., 201.Girard, A., 189.Given, P. H., 129, 135.Gladstone, M. T., 140.Glavind, J., 311.Glemser, O., 96.Glendenin, L. E., 83.Glendenning, M. B., 291.Glocker, R., 23.Glockler, G., 6, 9, 14, 22.Glover, R. E., 300, 305,Gliickauf, E., 85, 268, 269.Goebel, W. F., 299, 302.Goehring, M., 105, 106.Goepp, R. M., jun., 203.Gotsky, S., 21.Goldberg, A. A., 208, 313.Goldberg, G. M., 156.Goldberg, M. W., 207.Goldsmith, J.R., 90.Goldstein, M., 215.Goldstone, N. I., 332.Gollub, M. C., 266, 267.Gonick, E., 37, 50.Gonser, B. W., 98.Gonzdez Barredo, 334.Good, P. M., 274,282.173.309.foodall, R. R., 270, 272,Xoodson, L. H., 129.?oodwin, R. A., 324.Xordon, A. H., 270, 271,272, 273, 274, 276, 278,279, 283.Xordon, M., 233.forgy, S., 340.Xornall, F. H., 314.:oubeau, J., 93, 94.Sould, R. G., 267.Xoy, S., 327.Xradsten, M. A., 128.Xranacher, C., 215.fraassle, 0. E., 308.Xraham, A. R., 130.;raham, W., 193.franer, F., 103.f r m t , G. H., 71.;ray, L. H., 0, 9, 12, 26.freen, A. A., 40.freen, A. F., 306.keen, C., 274.keen, D. E., 244.>reen, N., 171, 173.Jreen, R. G., 173.Jreenberg, D. M., 242, 243,:reenberg, G. R., 250.Jreenstein, J.P., 266.Jreenwald, I., 90.Jreep, R. O., 289.Sreer, C. M., 35, 314.Jregor, U., 100.Jregory, J. D., 135, 279.Jreinacher, H., 16.Jrenall, A., 110.Jrenberg, A. A., 114.Jrewe, R., 192, 196.Grieger, P. F., 39.Griehl, W., 128.Griffith, A. S., 300.Griffith, R. L., 88.Griggs, M. A., 325.Grillot, E., 98.Grimm, H. H., 323.Grindley, J., 50.Grinstein, M., 254.Gripenberg, J., 189.Grisolia, S., 252, 266, 266.Grjhbine, T., 83.Grcanvold, F., 116.Gronwall, A., 312.Gross, A., 102.Gross, N. H., 264.Grove, D. H., 136.Grwsner, A., 200.Gudgeon, H., 277.Gunther, P., 19, 21, 23, 24.Guerin, H., 86.Guggenheim, E. A., 56.Guirard, B. M., 262.Guiter, H., 86, 87, 90, 91,103, 108, 117.Gundermann, J., 44.273, 275, 282.291.Jurland, J., 98.Juseva, A.P., 256.Juss, C. O., 303, 310.Jutfreund, H., 284.Juthrie, F. C., 333.Haagen-Smit, A. J., 276.Each, C. C., 113.Hackspill, L., 89, 90.Kadfield, (Miss) I. H., 334.Hansser, V., 96.Kagemann, F., 116.Hagen, S. K., 103.Hahn, P. F., 259.Hais, M., 267.Haissinsky, M., 19, 104.Halberstdt, E. S., 149.Hald, P. M., 329.Halder, B. C., 91.Kalev A., 151.Hall, g. A., 226.Hall, N. F., 335.Hall, R. T., 336.Haller, H. L., 164, 165, 166,167, 169, 170, 172, 173.Halls, E. E., 89.Halsall, T. G., 281.Hammarsten, E., 246, 249.Kammick, D. Ll., 129, 135,Hampton, B. L., 178.Hanby, W. E., 277.Hanford, W. E., 151.Hansley, V. L., 123.Happold, F. C., 226, 279.Hardegger, E., 204.Hmding, W.M., 233.Harpeaves, G. H., 123.Harington, (Sir) C., 214,Hark, 0. L., 113.Harker, D., 92.Harker, G., 22.Harkins, W. D., 38, 40, 41,Harmon, J., 151.Haroldson, H., 116.Harper, D. A., 325.Harper, S. H., 166, 169, 171,Harrad, G. J., 105.Harris, C. E., 219.Harris, G. A., 179, 180.Harris, G. C., 174, 175.Harris, G. M., 58, 95.Harris, I., 158.Harris, R., 271.Harris, S. A., 199,223,233.Harrison, G. C., 113.Harrison, H. C., 320.Harrison, J. A., 325.Hart, E. J., 24, 25.Hart, P. D., 304, 309.Harteck, P., 77.Hartford, W. H., 89.Hartley, F. R., 116.136.291, 301.42, 44, 47, 48, 49, 50.172, 173INDEX OF AUTHORS’ NAMES. 351Hartley, G. S., 34, 35, 36,39, 41, 42, 47, 49.Hartman, P. F., 144.Hartough, H. D., 129, 136.Hartzell, A., 165.Harvey, H.W., 339, 340,Harvey, J. A., 116.Harwood, M. G., 90.Haslam, H., 335.Hrtsler, M. F., 322, 323.Hassel, O., 183.Hasselstrom, T., 175, 176,Hastings, A. B., 241, 267.Hatfield, J. D., 94.Haugaard, G., 270.Hauptmann, H., 201.Hauser, C. R., 129.Hauser, E. A., 45.Hawkins, F., 312.Hawkins, J. E., 308.Hawkins, K., 218.Haworth, (Sir) N., 299,Haworth, R. D., 176, 182,Hawthorne, J. R., 281.Haynes, L. J., 133.Heap, R., 138.Hearn, P. F., 335.Heath, R. E., 116.Hecht, H., 85.Heer, J., 202, 205.Hegsted, D. M., 262.Heiber, W., 100.Heidelberger, M., 298, 299,301.Heilbron, (Sir) I., 130, 133,134, 206, 207, 208, 209,214, 216, 2G9, 277.342.177, 178.301.189.Hein, F., 107.Heiple, H.R., 69.Heisig, G. B., 9, 22.Heiss, H., 189.Helland-Hansen, B., 338.Helz, A. W., 325.Hemingway, A., 243.Hempelmann, L. M., 252.Hems, B. A., 215.Henderson, J. E., 16.Henderson-Hamilton, J. C.,Hendry, J. A., 215.Henry, A. J., 332.Herbert, A., 196.Herczog, A., 91.Herd, R. L., 335.Herman, D. F., 96.Hermann, R., 328.HBrold, A., 86.Herrera, C. G., 87.Herrold, R. D., 304.Hertwig, K., 93.Herzfeld, K. F., 55.Herzig, J., 190.319.Hess, D. C., 115.Hess, K., 44, 45.Hess, T. M., 323.Hesse, B., 85.Hesse, E., 310.Hessling, H., 317.Heuser, G. F., 233.Hevesy, G., 84, 239.Hewett, L. F., 302.Hey, D. H., 51, 139, 157,Heyd, J. W., 159.Heyes, J., 326, 327.Heyworth, F., 130.Hickey, A., 219.Hilgermann, R., 310.Hill, D.W., 283.Hill, E. G., 274.Hill, M. A., 136.Hill, P., 180.Hillion, (Mlle.) P., 331.Hills, G. M., 309.Hincks, E. P., 116.Hinshaw, H. C., 293, 303,305, 306, 307, 308.Hinshelwood, (Sir) C., 51,52, 53, 54, 55, 57, 58, 60,67, 68, 69, 70, 71, 72, 73,74.159.Hipple, J. A., 14.Hirsch, A., 309.Hirschfelder, J. O., 10, 15,20, 22, 64.Hirst, E. L., 273, 281.Hitchcock, M. W. S., 277.Hitchings, G. H., 234.Hobbs, J. E., 59.Hobson, L. B., 308.Hobson, R. P., 173.Hodge, W. W., 215.Hodgson, H. H., 130,Hohn, R., 175, 177.Hofer, W., 205.Hoffhine, C. E., 308.Hofmann, A. W., 207.Hoggarth, E., 307, 309.Hohn, F., 213.Holmberg, B., 208, 209.Holmes, (Mrs.) B., 31.Holzapfel, L., 21, 23, 24.Honig, R.’E., 6.Hood, R.L., 328.Hooper, I. R., 202.Hooykaas,R., 83.Hopher, T. H., 318.Hopkins, F. G., 245.Hopkins, S., jun., 176.Hopkins, S. H., 301.Hopwood, F. L., 8.Horn, D. H. S.,136.Horns, R. E., 271.Homing, E. C., 137.Horton, W. J., 211.Horton, W. S., 60.Horwitz, W., 114.159.Hosking, J. R., 180.Hotchkiss, R. D., 272, 275,Houben, J., 206, 208.Hough, L., 273, 281.Houlton, H. G., 341.Houtermsns, F. G., 97.Houtmann, A. C., 236.Howard, G., 277.Howitt, F. O., 283.Howlett, K. E., 60.Howton, D. R., 156.Huang, H. T., 192.Hubbard, D. M., 325.Huber, W. F., 138.Huckaba, C. A., 104.Hudson, C. S., 203.Huebschmann, P., 294.Hiirbin, M., 207.Hughes, E. W., 113.Hughes, G. K., 157.Hulburt, H. M., 60.Hulm, J. K., 90.Hultquist, M. E., 226, 227,Hulubei, H., 107.Hutchings, B.L., 226, 227,229, 230, 231, 233, 237.Hutchinson, C. A., 116.Hutchinson, G. W., 13.Hutchinson, W. S., 110.Hyde, E. K., 116.Hyman, A. T., 306.Ibanez, 0. G., 343.Iland, C. N., 312.Ingeldt, G., 91.Ingersoll, A. W., 129.Ingold, C. K., 197.Ingold, W., 334.Ingram, G. L. Y., 302, 311.Ireton, H. J. C., 22.Irmann, F., 89.Irvine, K. N., 300.Irving, H. M. N. H., 84.Isherwood, F. A., 271, 272,Ishiguro, T., 180.Ishmaui, Y., 310.Islay, O., 234.Isrmlarjhvili, S., 151.Ivancheva, A. G., 97.Ivsncheva, E. G., 97.Ives, D. J. G., 107.Izzo, P. T., 131.Jablonowski, H., 101.Jackson, D. T., 332.Jwobi, E., 111.Jacobs, H., 185.Jacobs, M. B., 332, 341.Jacobsen, J. P., 338.Jacobson, R.D., 330.Jaffee, R. I., 98,Jahn, F. P., 57.Jahn, K. F., 104.281.233.277352 1Jakabeim, J. J., 101.James, D. G. L., 30.James, W. O., 274, 282.Jamieson, C. A., 278.Jamieson I. M., 343.Jamsen, E. F., 201.Jansen, W. H., 326, 327.Jarrett,, I<. B., 158.Jazimirski, K., 336.Jean, M., 108, 109.Jefferies, H. S., 313.Jeffrey, G. A., 106.Jeffreys. H., 97.Jeger,- O., -174, 176, 186,Jellev, J. W.. 116.204, 205.Jelliiek, H. H. G., 60.Jenkins, 136.Jensen, E., 331.Jensen, E. U., 138, 140,150, 152, 153.Jensen, H. F., 283, 286,288.Jensen, K. A., 102, 111,114.Jepson, J. B., 207.Jobling, J. W., 294.Jochimsen, E., 300.J o b m y , S., 191.John, H. M., 262.Johnson, A. W., 132, 133,158, 274, 282.Johnson, G.M., 331, 332.Johnson, H. O., 329.Johnson, J. R., 200.Johnson, M. J., 270, 277.Johnson, M. W., 338, 342.Johnson, R. S., 219.Johnson, T. B., 307, 215.Johnson, W. F., 42.Johnson, W. W. A., 325.Johnstin, R., 325.Johnston, H. L., 85.Johnston, T. Y., 194.Jolibois, P., 116.Jones, E. R. H., 133, 134.Jones, I?. T., 90.Jones, G., 85.Jones, G. D., 317, 218.Jones, G. O., 86.Jones, J. K. N., 273, 281.Jones, R. G., 212.Jones, T. S. G. 275, 278,Jones, W. E., 130.Jordan, C. W., 331.Jost, W., 67.Joyce, R. M., 151.Joyner, A. L., 298.Juda, W., 85.Juday, C., 342.Jukes, T. H., 227.Julian, P. L., 216.Jungers, J. C., 19, 22.Jungileisch, (Mlle.) M. L.,280.90.DEX OF AUTHORS’ NAMES.Kabachnik, M. I., 138.Kaczka, E.A., 233.Krtertkemeyer, L. , 2 1.Kagan, M. Y., 5s.Kahn, E., 174.Kailan, A., 6, 22.Kaiser, H., 318, 322.Kalckar, H. M., 246.Kalle, K., 339, 340.Kamen, M. D., 239, 254,Kampitsch, 84.Kmtzer, (Mlle.) D., 101.Kapitanczyk, K., 94.Kaplan, N. O., 260, 261,Kara-Michmlova, E., 16.Karabinos, J. V., 201, 204,Karantassis, T., 114.Kmimullah, 207.Karlson, A. G., 308.Karrer, P., 156, 201, 228,234, 235, 236.Kasatotschkin, W., 104.Kasper, J. S., 92.Kassel, L. S., 56, 61, 67.Kassell, B., 286.Kassner, E. E., 331.Kassner, J. L., 331.Katzin, 1;. T., 116.Kaufmann, S., 177.Kauter, C., 174.Kay, H. F., 90.Kayne, G. G., 300.Kazeeva, E. V., 175.Keck, P. H., 322.Keck, R. H., 318.Keene, J. R., 14.Keesom, W. H., 82.Keighley, G., 276.Keimatsu, S., 1SO.Keiser, F.S., 77.Kelland, N. S., 77.Keller, R., 207.Kelly, W., 208.Kemmerer, G., 339, 340,Kemp, J. W., 323.Kench, J. E., 254.Kennedy, C. R., 293, 300,Kennedy, D. J., 123.Kenner, G. W., 199, 214.Kenner, J., 196.Kenny, T. S., 215.Kent, P. W., 299,301.Keresztesy, J. C., 199, 227,Kern, W., 217.Kernbaum, M., 23.Kerr, W. A., 319.Kertscher, F., 327.Kessler, K. G., 323.Keston, A. S., 241, 276,260.262.218.341.302, 306.231.287.Ketchurn, B. H., 340.Ketelaar, J. A. A., 99.Keuhemans, A. I. M.,Keyes, F. G., 104.Keys, A., 343.34.Khirkch, M. S., 118, 138,140, 141, 146, 150, 152,153, 154, 157, 160, 161.Kibler, R. F., 129.Kiors, R. J., 319.K!essig, H., 44, 45, 47.Kindler, K., 206, 207, 211,King, C., 319.King, E.J., 341.King, J. A., 211, 212, 213.King, W. H., 331.Kinley, W. N., 224.Kirby, H., 272.Kistiakowski, G. B., 64.Klebansky, A. L., 124.Kleiderer, E. C., 124.Klein, O., 12.Kleinberg, J., 86, 110, 11 1.Klem, A., 341.Klemm, L. H., 202.Klemperer, F. W., 25 1,Klevens, H. B., 38.Kline, G. M., 216.Kloetzel, M. C., 303, 310.Klute, C. H., 54,60.Klyne, W., 328.Knight, B. C. J. G., 311.Knippenberg, E., 328.Knudsen, M., 338.Koch, H. P., 142, 161.Koch, J., 85.Koch, R., 299.Kocheshkov, K. A., 130.Koeck, H., 215.Korosy, F., 87.Kolb, J. J., 332.Kolmer, J. A., 305.Kolthoff, I. M., 42, 332,Kolumban, A. D., 15.Komschilov, N. F., 175.Kondratev, V., 80.Kondratev, V. N., 75, 76,Kondratevra, E., 80.Kondrateva, E. I., 76, 79.Kondrateva, H., 76, 80.Kono, M., 175.Kopsch, U., 77.Kornberg, A., 266.ICornfield, E.C., 124.Kortiim, G., 110.Korzh, P. D., 325.Kosak, A. I., 129.Kosolapoff, G. M., 129,Kossiakoff, A., 55.Kostyuchenko, L. A., 66.Koubra, D. L., 333.Kovalsky, A., 75.212.336.79, 80.138INDEX OF AUTHORS' NAMES. 353Krlihenbuhl, W., 205.Kraft, K., 177.Krainich, H. G., 343,Kramer, W., 263.Kramers, H. A., 63.Krampitz, L. O., 261, 265.Krasny-Ergen, W., 116.Kraus, C. A., 38, 39.Krebs, H. A., 250, 265.Krenz, F. H., 18.Kreps, E., 340.Krestinski, V. N., 175.Krishnmurti, P., 45.Kriukov, P. A., 344.Krius, A., 106.Krogh, A., 341,343.Kroll, W. J., 98.Kroner, T. D., 270.Krsek, G., 134.Kubaxchewski, O., 104.Kuderna, B. M., 152.Kuchler, L., 60.Kuehl, F.A,, 308.Kuehl, F. A., jun., 202.Kuh, E., 226, 227.Kulkarni, D. R., 107.Kummer, J. T., 100.Kuna, S., 308.Kunin, R., 116.Kuzin, A. M., 256.Kwantes, A., 134.Kwasnik, W., 100, 106,109.Lachampt, F., 46.La Corn, L. F., 278.Lacourt, A., 215.Lafitte, M., 91.La Forge, F. B., 164, 165.166, 'i67, 168,- 169; 170;171, 172, 173.Laidlaw. P. P.. 298.111111111111111II1111I11Laitinen, H. A., 332.Lalande, W. A., jun., 177.hmbert, F. L., 160.La Mer, V. K., 331.Lampen, J. O., 205.Lamure, J., 91.Landler, I., 7.hndolt, F., 128.Sane, W. R., 334.Lange, B., 300.iangsjoen, A., 217.Langstroth, G.O., 319.+ning, S. H., 106.Japorte, R., 300.;amen, A. H., 86.k s h , A. E., 13.;arson, E. M., 82.Latarjet, R., 24.Latiu, E., 330.Laubengayer, A. W., 93.Lauchlan, A. D. E., 333.Lauti6, R., 107.REP.-VOL. XLV.imge, w., 102.Amgrnu~, I., 285.Lautsch, W., 216.Lavin, G. I., 16, 25.Lawrence, A. S. C., 34, 57.Lawrie, R. A., 278.Lazarus, L. H., 37.Lea, D. E., 5, 6, 28, 31.Le Beau, L. S., 45.Lecante, J., 101.Lederer, M., 283.Lederer, N., 174.Lederle, P., 328.Lefort, M., 6,23,24.Lehmann, J., 306.L e b n n , W., 327.Leichter, 19.Leichtle, P. A., 320.Leifer, E., 54, 252.Leighton, P. A., 216.Leikend, M. C., 84.Lemaire, H. P., 88.Lemieux, R. V., 202.Leonard, J. W., 106.Le Peintre, M., 94.Lersson, E., 41.Lessing, F.P., 92.Lessmann, O., 94.Lesuk, A., 299.Letort, M., 52, 54.Letort, N. M., 54.Lettr6, H., 192.Letts, E. A., 342.Leuchtenberger, C., 227.Leuchtenberger, R., 227.Leuckart, R., 129.Leutenegger, W. E., 156.Levene, P. A., 213.Levi, A. A., 268, 270, 272,273, 275, 277, 282.Levi, M., 276, 287.Levi, T. G., 208, 213.Levin, R. H., 204.Levine, C., 274.Levine, H. A., 125.Levine, P., 283.Levine, R., 129.Levy, A. L., 216.Levy, E., 174.Levy, S., 317.Lew, B. W., 203.Lewis, B., 19, 67, 68, 69,70, 71, 72, 73, 74, 75, 77,Lewis, J. A., 84, 271.Lewis, M. R., 299.Lewisohn, R., 227.Li, T., 212.Libermann, D., 215.Lichtenberger, J., 136.Liddell, H. F., 276.Lieanu, C., 109.Lieb, H., 343.Liebhafsky, H. A., 86, 333.Liebig, G.F., 319.Liechti, A., 25.Lifson, N., 243, 263.Liggett, L. M., 113.Lilliendahl, W. C., 98.Lind, S. C., 6, 14, 18, 19, 21,Lindenbaum, A., 254, 267.Lindley, H., 278.Lindner, F., 284.Lindsay, J. E., 333.Lindstrom, B., 275.Lingafelter, E. C., 38, 50.Lingane, J. J., 332, 333,Linggood, F. V., 282.Linhard, M., 101.Linkasiewicz, S. J., 136.Linsted, R. P., 84, 271,Lipmann, F., 260, 261, 262.Lipton, M. A., 262.Littmann, E. R., 176.Litz, L. M., 116.Livingood, J. J., 288.Livingston, M. S., 10.Livingston, R., 9, 102, 116.Livingston, R. S., 18, 19,Locdio, S. A., 257.Lock, G., 136.Lockwood, W. W., 290.Loeb, L. B., 14.Loebel, R. O., 303.Loftfield, R. B., 95.Lohmann, A., 25.Loiseleur, J., 24, 30.Lomakin, B.A., 320.22.334, 337.283.21.Lombard, R., 174, 176, 177,183.London, I. M., 254, 259.Long, E. R., 292, 295, 298,299, 303, 305, 310, 315.Long, S. H., 111.Longenecker, W. H., 272.Lopez, A. C., 312.Lorber, V., 243, 244, 263.Loscalzo, A. G., 334.Loudon, J. D., 193, 194,195, 196, 198.Lounsbury, M., 85.Lourie, A., 319.Lowy, P. H., 276.Lucas, C. C., 341.Lucas, V. E., 159.Lucht, C. M., 92.Lutgert, I., 333.Lugg, J. W. H., 279, 282.Lukes, R., 176.LundegBrdh, H., 325, 327.Lunstman, B., 103.Lutz, A. H., 205.Lutz, F. B., 340.Lux, H., 111.Luyckx, A., 16.Lykken, L., 329.Lyman, J., 338.Lynen, F., 263.Lyness, W. I., 159.Lythgoe, B., 199, 205, 207,209, 214.354 INDEX OF AUTHORS’ NAMES.McBain, J.W., 37, 38, 39,McBay, H. C., 141, 146.McBride, J. J., 157.McCarter, J. R., 302, 311.McClosky, W. T., 305.McCollum, E. V., 279.McCombie, H., 138, 139.McCordock, H. A., 292.McCormack, W. B., 158.McCutcheon, P., 87.McDermot, W., 308.McDonald, D. K. C., 99.McDonald, R. A., 116.McElroy, 0. E., 262.McEwen, W. L., 222, 223,McFadyen, J. S., 214.McGilvery, R. W., 242.McEsn, H., 41.McHargue, J. S., 330.Mecheboeuf, M., 272.Madder, R. C., 319.McIlwain, H., 311, 312.McIntosh, A. V. jun., 204.McKail, J. E., 216.McKee, F. S., 77.McKenna, J. F., 217.Mrtckenzie, C. G., 252.MacKenzie, R. C., 74.McLennan, J. C., 22.McMillan, F. H., 211, 212.MmMillan, J., 193, 198.Macnamara, J., 92.McOmie, J. F. W., 208, 214.McPheat, J., 325.Macpherson, H.T., 287.McPherson, J. D., 175, 176,McReynolds, R. C., 318.Macris, G. D’Costas, 332.McRoberts, T. S., 43.MacTurk, H. M., 311.McWhirter, M., 200.Maddock, A. G., 96, 116.Madigan, D. G., 306.Madinaveitia, J., 31 1.Madorsky, 5. L., 91.Mader, H., 317.Magat, M., 7.Magram, S. J., 59.Mahadevan, A. P., 130.Mahncke, H. E., 343.Majumdar, A. N., 113.Maki, T., 136.Malan, R. L., 212.Malapride, L., 330.Malatesta, L., 113, 115.Malevskaja, S. S., 177.Maley, L., 84.Mallet, L., 16.Mallette, M. F., 233, 234.Malpica, J. T. M., 322.Malsch, J., 39.Mann, F. C., 293, 306, 307.Mann, F. G., 126, 138.40,41,42,50.224.177.Manolescu, T., 42.Ilanz, G., 198.March, L. E., 82.Marchand, B., 198.Marcovich, V.G., 79, 80.Ilargulis, H., 102.Marinsky, J. A,, 83.Markarien, M., 157.Markham, R., 278.Marron, T. U., 42.Marshall, I., 158.Marshall, L. M., 277.Harshall, R. A., 277.VIartin, A. J. P., 267, 268,269, 270, 271, 272, 273,274, 276, 277, 218, 279,280, 282.Martin, A. R., 307, 309.Martin, D. R., 93.Martin, F. W., 22.Martin, G. J., 233.Hartin, J. T., 165.%artin, L., 136.aaruyama, R., 175.Marvel, C. S., 154.Mas, R., 86.Mmon, C. M., 94.Massey, H. S. W., 14.Massie, S. P., jun., 219.Masters, R. E., 254.Mathews, R. E. F., 278.Mathieson, A. McL., 105.Mathur, K. B. L., 155.Mattano, L. A., 212.Mattensen, L., 103.Matthews, D. J., 338, 340.Mattick, A. T. R., 309.Mattoon, R. W., 44, 47.Maw, G. A., 274, 282.Maximow, A.A., 295.Maxted, E. B., 82.May, A. N., 116.May, E. L., 214.Mayberry, M. G., 105.Mayer, R. L., 304.Mayer, S. W., 268.Mayors, K. R., 318.MXBdard, L., 104.Meerbott, W. K., 60.Megaw, (Miss) H. D., 90.Mehler, A. H., 265.Meikle, W. J., 333.Meinzer, E. M., 204.Meissner, G., 310.Melchior, J. B., 241.Melchior, N. C., 84.Mellanby, (Sir) E., 295.Mellon, M. G., 341.Mellor, D. P., 84, 95, 114.Melluish, R. R., 133.Meloche, V. W., 339, 340.Melville, D. B., 199.Melville, K. I., 310.Melvin, E. H., 325.Riendelssohn, K., 85.Menzel, A. E. O., 301.Mercer, R. D., 233.Meredith, W. J., 25.Merrill, R. C., 42.Merritt, R. P., 163.Merz, J. H., 159.Metayer, M., 124.Metchnikoff, 293.Metzlor, D. E., 332.Meden, P. A.van der,Meyer, G. M., 213.Meyer, K., 191.Meyer, K. H., 46.Meystre, C., 156.Micheel, F., 213.Michel, (Mine.) A., 112.Michelson, A. M., 138.Middlebrook, W. R., 274.Miescher, K., 156, 202, 205.Mikkelson, D. S., 329.Milas, N. A., 59, 146.Miles, A. A., 301.Miller, G. L,, 284, 286.Miller, N., 8, 9, 31, 32.Miller, W. W., 95.Millington, R. H., 263.Mills, H., 105.Minder, W., 25.Minkoff, G. J., 77, 104,Misra, G. S., 157.Mitchell, A. D., 82.Mitchell, H. K., 226.Mitchell, R. L., 324, 329.Mittelmann, R., 280.Mitton, H. E., 110.Miyamichi, E., 207.Mizel, A. E. O., 299.Moeller, T., 94, 100, 116.Moen, J. K., 299.Mohler, F. L., 13.Montavon, R. M., 204.Montignie, E., 93, 99, 107.Moon, C. H., 19.Moore, B. P., 182, 189.Moore, C.V., 254.Moore, M. L., 129.Moore, S., 271, 272, 279.Moore, T. E., 102.Morette, A., 103.Morgan, W. T. J., 274, 281.Morgan&, M., 176.Moring-Claesson, I., 243.Moritz, H., 318, 319, 320.Morris, J. C., 53.Morrison, G. A., 280.Morse, S., 10, 24.Moses, H. E., 305.Mosley, V. fit., 275, 280.Moss, J., 233.MOSS, M. L., 336.Motschan, I., 6.Mowat, J. H., 226,227,230,231, 233, 237.Mowry, D. T., 126, 127.Moyer, A. W., 221.106.149INDEX OB AUTHORS’ NAMES, 356Moyle, V., 271, 277.Mozingo, R., 124, 199, 200,Muffling, L. von, 81.Mueller, D. W., 14.Muller; R. H., 326.Muir, E., 306.Muir, H. M., 255.Mukerjee, S., 203.Mullinger, L. W., 116.Mund, W., 6, 18, 19, 21, 22.Munday, B., 299.Mundell, M., 277.Munter, P.A,, 278.Muntwyler, O., 172.Murgulescu, I. G., 330.Murray, A. G., 215.Murray, E. H., 136.Murray, W. M., 320.Muschenheim, C., 308.Mushett, C. W., 308.Mustafa, A., 135.Mutter, W. E., 58.Myei, N., 304.Myers, A. J., 325.Myers, A. T., 329.Myers, R. J., 332.Myers, W. R., 111.Nachmansohn, D., 262.Nachod, F. C., 333.Nadeau, G. F., 336.Nahstoll, G. A., 323.Naik, K. G., 100.223, 233.Nalbandyai, A. B., 69, 71,75. 77.Nas< R.; 100.Nayar, M. R., 111.Naylor, J., 341.Nazzewski, M., 157.NBgre, L., 301.Neher, R., 156.Nehring, K., 328.Neu, R., 165.Neubauer, L. G., 180, 182.Neuberger, A., 255, 291.Neudorffer, J., 109.Neufeld, 0. E., 335.Neuhaus, C. J., 320.Neumann, M. M. C., 217.Newbold, G. T., 214.Newbound, K.B., 319.Newman, M. S., 128, 302,Nichols, J., 215.Nichols, M. L., 325.Nicholson, J. S., 189.Niederhauser, W. D., 125.Nielsen, J. K., 308.Nielsen, K., 89.Miemann, C., 334, 337.Nier, A. O., 85, 243.Nierenstein, M., 189.Nigre, L., 310.Nilssen, B., 331.Nishigaki, M., 310.311.Nishina, Y., 12.Nisoli, C., 205.Nocito, V., 244.Noonan, T. R., 254.Nordblom, Q. F., 101.Norman, D. P., 325.Norris, L. C., 233.Norris, L. D., 95.Norris, T. H., 95.Norrish, R. G. W., 77.Northey, E. H., 226, 227.Norymberslca, L., 202,Norymberski, J., 202, 204,Nosenko, D. S., 65.Novak, A., 175.Novelli, G. D., 262.Nozaki, K., 143, 145, 147.Nurnberger, C. E., 24.Nyholm, R. S., 112, 113,Nystrom, R. F., 122, 123.Oberhauser, F., 106.O’Brien, T.D., 92, 107.Ochoa, S., 265, 266.O’Connor, J. J., 40.O’Connor, R. T., 325.O’Dell, B. L., 229.&-strom, A., 250.Orstrom, M., 250.Oesper, R. E., 333.Ogg, E. F., 21.Ogg, R. A., 56.Ogg, R. A., jun., 99, 100.Oglethorp, G. C., 332.Ogston, A. G., 284.Ohe, H., 123.Ohle, H., 218.Ohlendorf, H., 130.Olalde, A., 202.Olcott, H. S.. 291.Oldenburg, O., 16, 69, 76.Oldfield, J. H,, 326.Oleson, J. J., 233.Ollis, W. D., 214.Olmer, L. J., 106.Olsen, N. S., 243, 244.Openshaw, H. T., 138, 208.Opie, E. L., 294.Oppenheim, J. C., 335.Oppenheimer, E. H., 294.Oppenheimer, H., 40, 41.Oriana, R. A., 109.Ormont, B., 87.Ormondt, J. van, 88.O’Rourke, L., 312.Orten, J. M., 277.Osadchih, M., 340.Osipov, V.N., 102.Ostertag, (Mlle.) H., 89.Oswald, E. J., 308.Ott, A. C., 212.Overell, B. T., 282.Overman, R. R., 329.Owen, L. N., 123.205.115.Owsley, W. D., 318.Oxford, A. E., 142.Oxley, M. W., 127, 128.Om, T. M., 100.Pacilli, (Signa.) E., 86.Page, E., 279.Page, J. E., 132.Pagel, W., 300.Paige, M. F. C., 309.Paine, F. J., 309.Palin, D. E., 95.Palit, S. R., 335.Palkin, S., 174, 176, 177,Pamfilov, A. V., 97.Paneth, F. A., 85.Panizzon, L., 214.Papa, D., 201, 212.Paquette, R. G., 38.Paris, R., 101.Park, G. S., 159.Parker, L. F. J., 278.Parkes, T. D., 329.Parks, R. Q., 324.Parry, R. W., 107.Parsons, D. S., 280.Parsom, J. L., 332.Parsons, L. B., 105.Partington, R. G., 60.Partridge, M. W., 127, 278.Partridge, S.M., 274, 281,Pascal, P., 107.Pasternak, V. Z., 182.Patat, F., 52.Patel, S. Z., 100.Patrick, W. L., 22.Patry, N., 99.Patterson, W. I., 277.Pattison, D. B., 211.Patton, A. R., 274.Paul, A. J., 305.Pauling, L., 82, 84.Pauly, A., 301.Pauson, P. L., 189.Pavlov, D. S., 79.Pavlov, v. I., 7.Peacock, M. A., 89.Peak, D. A., 207, 210.Pearlson, W. H., 96.Pearson, T. G., 16, 105.Pease, R. N., 51, 52, 55, 57,59, 65, 68, 69.Peck, R. L., 297, 308.Pecsok, R. L., 333.Pelzer, H., 62, 63.Pekarek, E., 290.Penner, M., 306.Percival, E. G. V., 281.Pereira, G. J., 343.Perkin, A. G., 189, 190.Perkins, F, M., 190.Perkins, P. D., 136.Perkins, W. A., 216.Pcrouze, J., 106.178, 179.283356 INDEX OF AUTHORS’ NAMES.Perrin, M.W., 22.Perry, J. M., 22.Persson, S. H., 110.Peschke, W., 206.Petering, H. G., 235.Peters, E. D., 335.Petersen, M. H., 270.Petersen, W., 294.Peterson, B. W., 25.Peterson, E. W., 323.Peterson, W. H., 226, 277,Petrich, K., 332.Petrov, A. A., 126.Peyronel, G., 86.Pfau, G. M., 215.Pfeiffer, M.; 170.Pfeilsticker, K., 322, 325.PfXner, J. J., 229.Pfister, R. J., 323.Pfuetze, K. H., 306.Philippoff, W., 44, 45, 47.Phillips, D. M. P., 273, 274,Phillips, H., 274, 276.Phillips, J. T., 8.Phillips, M. A., 130.Phillipson, A. T., 277,Pickel, F. D., 214.Pierron, P., 110.Pierson, E., 131.Pietrusza, E. W., 153.Piffault, 24.Piggot, H. A., 197.Piggott, W. A., 127.Pillemer, L., 301.Pinazzi, C., 105.Pink, R.C., 43.Pinkston, J. T., jun., 109.Pinner, M., 299.Pitter, A. V., 37.Pittman, R. W., 107.Platz, H., 79.Plentl, A. A., 246.Plimmer, H., 180.Poe, C. F., 260.Poetzelberger, R., 317, 319.Pohl, W., 173.Polanyi, M., 69.Polgar, N., 297, 298, 314.Polglase, W. J., 202, 215.Pollard, A. J., 271.Pollock, M. W., 128.Polly, 0. L., 52.Polonovski, M., 215.Polson, A., 275, 278, 280.Polyakov, M. V., 65.Popescu, M., 43.Popov, L. D., 124.Popper, P., 90.Portal, E., 87.Porter, F., 21.Porter, R. R., 277.Portevin, A., 86.Postovskii, I. Y., 310.Potter, C., 166.342.278, 289.Potts, G. D., 99.Potts, J. E., jun., 99.Pouget, L., 340.Pound, J. R., 332.Pourbaix, M., 90, 104.Powell, C. F., 5.Power, F. B., 314.Pozhiltzova, E.A., 128.Praagh, G. van, 96.Pramanik, B. N., 313.Pratt, J. J., 274.Prelog, V., 204, 205.Prettre, M., 69.Price, C. C., 139, 157.Price, D., 214.Price, T. D., 95.Priest, H. F., 108.Prijs, B., 205, 307.Prill, E. J., 154.Prince, A. L., 329.Prins, D. A., 203.Prins, H. J., 96.Probst, R. E., 85.Prokof’ev, V. K., 317.Prytherch, H. F., 344.Pugh, W., 332.Pupko, S., 99.Purkayastha, B. C., 98.Pushkareva, Z. V., 310.Quaglino, J. V., 77.Quarrell, A. G., 317.Quest, G., 310.Querry, M. V., 221, 222,Quilliam, J. P., 139.Quilliam, T. A., 139.Quinby, 0. T., 101.Quintin, (Mlle.) M., 91.Raab, W., 310, 313.Raben, E., 338, 340, 342.Rabinowitch, E., 17.Radin, N. S., 239.Raffel, S., 300.Rai, J., 155.Raistrick, B., 188.Rajchman, J. A., 323.Rake, G., 308, 309.Rakestraw, N.W., 340,343.Raleigh, G. W., 307.Raley, J. H., 59, 146, 147,Ralph, C. C., 320.Ralston, A. W., 37, 38, 39.Ramahandran, B. V., 106.Ramage, H., 325.Ramberg, L., 331.Ramay, (Sir) W., 7.Ramsey, L. L., 277.Rsmsperger, H. C., 66, 61.Rrtmstetter, H., 66.Randall, S. S., 272.Rank, D. H., 323.Raper, R., 273.Rat,hje, W., 327.223.149.Ratner, S., 241,244.Rau, M. G., 163.Raudnitz, H., 174.Rauteberg, E., 328.Ravel, J. M., 233, 2!0.Ray, P., 113.Ray, R. C., 88, 111.Raymond, S., 87.Raynaud, A,, 86.Razumova, S. A., 114.Re&, F. W., 342.Read, J., 6.Reber, F., 214.Rebstock, M. C., 308.Redfield, A. C., 340.Reed, H. W. B., 169, 173.Rees, M. W., 287.Reichard, P., 246, 282.Reichstein, T., 191, 203,Reid, E.E., 334.Reid, J. C., 212.Reid, W. B., jun., 201.Reiling, V. E., 16.Reinhold, H., 105.Reiniger, G., 318.Reinmuth, O., 152.Reis, L., 243.Reitz, H. C., 291.Renfrew, 298.Reno, N. E., 137.Renquist, M. L., 216.Rentschler, H. C., 98.Reppe, J. W., 132.Rhoads, C. P., 257.Rhodes, R. G., 90.Riabtschikov, D. I., 115.Riblett, E. W., 57.Ricci, J. E., 52.Rice, F. O., 52, 54, 55, 60.Rice, 0. K., 56, 61.Rich, A. R., 292, 293, 297,Richardson, D., 328.Richardson, E. M., 214.Richardson, G. M., 336.Richardson, H. B., 303.Richmond, J. H., 195.Richter, C., 326, 327.Rickes, E. L., 231.Riddel, W. A., 342.Rideal, E. K., 18.Rider, A. A,, 279.Riehm, H., 328.Rieke, F.F., 76.Rienacker, G., 106.Riener, T. W., 124, 125.Riggert, K., 5.Riley, D. P., 48.Riley, G. A., 344.Rimington, C., 257, 259,Ripan, R., 109.Ripert, J., 165.Risler, T., 96.Rime, O., 23, 24, 26.214.299, 300.273INDEX OF AUTHORS’ NAMES. 357Rist, N., 305.Ritchie, M., 51, 74.Rittenberg, D., 212, 239,241, 242, 246, 249, 252,253, 254, 255, 259, 262.Rivenq, F., 103.Rivers, R. V. P., 214.Roberts, J. S., 61.Robertson, A., 155, 159.Robertson, J. M., 105.Robertson, N. C., 65.Itobinson, C., 39.Robinson, H. A., 334.Robinson, P. L., 92, 105.Robinson, (Sir) R., 131,200, 207, 208, 297, 298,300, 314.Robinson, R. A., 112.Robinson, R. I., 339, 340.Robinson, R. J., 339, 341,Roblin, R. O., j u . , 205.Rochford, D., 342.Rochow, E.G., 97.Rodden, C. J., 286.Rodebush, W. H., 77.Rodriguez, M. M., 104.Roe, E. M. F., 192, 194.Roe, J. W., 42.Roelen, O., 134.Rogers, L. H., 324, 325.Roginsky, S., 6.Rogler, E., 85.Rohmlehrer, L., 327.Rohner, F., 317, 318.Rohrback, G. H., 109.Roll, P. M., 246, 250, 251.Rollefson, G. K., 54, 95.Rollinson, C. L., 82.Rose, F. L., 215.Rose, J. D., 176.Rosenberg, I. M., 267,Rosenblum, C., 21, 23.Rosenheim, O., 273.Rosetti, F., 10.Ross, A. G., 281.Ross, D. J., 182.Ross, S. D., 157.Rossiiskaya, P. A., 138.Roth, L. J., 252.Roth, W. L., 54.Rothen, A., 289.Roudier, A., 281.Rougeot, L., 99, 106.Rowley, H. H., 60.Rubin, L. C., 57.Rubinstein, A. M., 114.Rudall, K. M., 286.Rue, S. O., 331.Rudorff, G., 95.Rudorff, W., 95, 96.Ruehle, A. E., 317,324, 334.Ruhemann, S., 219.Rule, A.M., 305.Rump f-No rdmann, (Mme. )M. E., 104,342, 343.Rundle, R. E., 116.Runnicles, D. F., 42.Rushbrooke, G. S., 61.Rushman, D. F., 90.Russell, H., 82.Russell, R. G., 325.Rust, F. F., 59, 146, 147,Rutan, P. V., 211.Ruzicka, L., 119, 162, 163,164, 165, 166, 168, 170,171, 172, 173, 174, 176,177, 178, 184, 185, 186,205, 207.148, 149.Ryder, C. T., 297.Rydon, H. N., 276, 277.Ryman, 8. E., 215.Rymer, J., 309.Rys, I. G., 93.Sabin, F. R., 292, 295, 297,Sachsse, H., 52.Sacks, J., 35, 239, 314.Safir, 8. R., 221, 222, 223.Sahai, R. B. N., 111.Sahney, R. C., 111.Sahyun, M., 288.Sakami, W., 243,244,263.Sakellarides, P., 114.Sakurada, Y., 208.Salomon, K., 254.Salute, E., 243.Samek, B., 332.Samis, C.S., 39.Sanderman, W., 175, 176,Sanderson, T. F., 174, 175,Sandin, R. B., 158.Sanger,F., 277,279,288,289.gantavf, F., 192.Sauer, H., 96.Saunders, B. C., 126, 138,Saunders, J. A., 333.Saunders, K. H., 158.Saunderson, J. L., 319, 322,Sawyer, R. A., 317, 319.Scarisbrick, R., 271, 277.Schaeppi, Y., 107.Schafer, K., 85.Schatz, A., 307.Schaufelberger, F., 91.Schechter, A., 6.Schechter, W. H., 86.Schenk, P. W., 79, 80, 101,Scheuer, O., 23.Schifferli, J., 42.SchiHett, C. H., 22.Schilling, J. R., 279.Schlechten, A. W., 98.Schlesinger, H. I., 122.Schmeidler, G. A,, 183.298.177.179, 180.139.323.106.Schmeisser, M., 100, 101.Schmid, H., 156, 201.Schmitt, L., 327.Schmitz, H., 109.Schmitz-Dumont, O., 102.Schneider, E., 105.Schneider, E.G., 76.Schnider, O., 200.Schnizlein, J. G., 94.Schonberg, A., 135.Schoenheimer, R.. 239, 241,Schoning, I., 41.Schoental, R., 198.Schoepfle, C. S., 22.Schomaker, V., 105.Schramm, R., 137.Schroer, E., 333.Schubert, C. C., 60.Schubert, J., 254, 267.Schubert, J. D., 267.Schuch, J., 319.Schuch, J. A., 326.Schuhknecht, W., 327.Schulman, J. H., 43, 48.Schulman, M. P., 242.Schultze, A., 132,Schultze, G. R., 60.Schumacher, H. J., 51, 59,Schumb, W. C., 97, 108.Schwabacher, H., 304.Schwarz, R., 96, 97, 100.Schwarz, W., 326.Sohwarzenbach, G., 84, 187.Schweitzer, G. K., 116.Schwenk, E., 201, 212.Schwob, Y., 89.Schwyzer, R., 228, 235,Scott, A.B., 38, 50.Scott, D. A., 288, 290, 291.Scott, G. P., 192.Scott, (Miss) J. D., 82.Scott, M., 309.Scott, M. L., 233.Scott, R. O., 321, 324.Scott, T. R., 93, 98.Scribner, B. F., 318.Seaborg, G. T., 116, 117.Sealock, R. R., 285.Sears, C. A., 136.Sease, J. W., 337.Sedov, J. S., 318.Seeger, D. R., 226, 227, 233.Seel, F., 102.Segel, E., 137.Seibert, F. B., 298, 299, 301,Seibt, S., 172.Seith, W., 317.Sellers, H. G., 144.Selwood, P. W., 94.Selye, H., 302.Semb, J., 226, 227, 230, 231,233, 237.245, 246.109.236.303368 INDEX OF AUTHORS’ NAMES.Semenov, N. N., 67, 69, 75,77, 78, 79, 81.Semon, W. F., 158.Sengir, E., 310.Sen-Sarma, R. N., 98.Serijan, K. T., 218.Seubold, F.H., 59, 147,Sexton, W. A., 92.Shaffer, P. A., 334.Shah, C. C., 100.Shanley, E. S., 104.Shantarovich, P., 77.Shantz, E. M., 212.Shaw, G., 208.Shaw, G. T., 59.Shaw, J., 273.Shaw, J. A., 88.Shaw, J. H., 100.Sheehan, J. C., 131.Sheets, D. G., 206.Shemin, D., 239, 241, 242,249, 253, 254, 255, 259.Sheppard, C. W., 6.Sherman, H., 299.Sherrard, E. C., 189.Sherry, P. G., 219.Sherwood, I. R., 180.Sheverdina, N. I., 130.Shipley, F. W., 201.Shishakov, N. A., 24.Shive, W., 233, 250.Shockley, W., 86.Shoppee, C. W., 155, 197.Shorr, E., 303.Short, W. F., 127, 128, 180.Shovers, J., 333.Shrader, E. F., 110.Shubina, S., 69, 77.Shulek, E., 333.Sickels, J. P., 226, 227.Sickmm, D. V., 52.Siebert, H., 94.Siedel, W., 259.Siegwart, J., 208, 235.Sifferd, R.H., 285.Siggia, S., 334.Silber, P., 89.Silbiger, G., 92.Silbur, R. H., 308.Sillen, L. G., 91, 103, 268.Silver, S. D., 337.Silverstein, M. S., 101.Simon, E., 40.Simon, F. E., 86.Simonenko, D. L., 98.Simons, J. H., 96.Simonsen, (Sir) J., 163.Simpson, J. E. C., 229.Sinclair, D. A., 319.Sinex, M., 267.Singh, S., 111.Sinha, P. C., 88.Sisler, H. H., 86, 97.Sjogren, B., 284.Skell, P. S., 153.148, 149.Skolnik, S., 101.Skorodumov, V. A., 218.Slack, C. M., 7.Slack, R., 159.Slater, N. B., 62, 63.Slimowicz, C. E., 182.Sloane, N. H., 229.Slotin, L., 252.Slotkin, G. E., 314.Slottman, G. V., 41.Smith, A. H., 277.Smith, C., 15.Smith, C. G., 332.Smith, D.M., 316.Smith, E. C. B., 274, 282.Smith, E. L., 132, 276, 278,Smith, G. F., 331,. 332.Smith, G. S., 317.Smith, H. M., 86.Smith, H. P., 25, 340.Smith, J. H., 55, 56.Smith, J. M., jun., 226, 227,Smith ,T. R.E., 52,53,54,58.Smith, K. I$., 278.Smith, L. I., 215.Smith, M. I., 306.Smith, M. J., 305.Smith, N., 333.Smith, N. O., 107.Smith, R. E., 52.Smith, S., 305.Smith, W. T., jun., 111.Smith, W. V., 69, 76.Smithburn, K. C., 297, 298.Smyth, C. P., 109.Smyth, H. D., 14.Snell, A. H., 95.Snell, E. E., 226.how, G. A., 311.Snyder, H. R., 157.Snyder, R. L., 323.sober, H. A., 337.Sorensen, N. A., 180.soldate, A. M., 42.3011, J., 106.3olomon, A. K., 241.3olotorovsky, M., 308.Soloway, S. B., 168, 169,Sommer, F., 333.Sommer, L.H., 153, 156.Sommers, A. H., 218.sommers, H. S., 69, 76.Somogyi, Z., 336.Sonderhoff, R., 263.Sondheimer, F., 133.Sonne, J. C., 247.loper, Q. F., 212.Soper, W. B., 293.Sopor, N. P., 126.Sorkin, E., 205.lorkin, M., 191.loskin, S., 283.louchay, P., 103, 108, 109.282.233.173.Southwick, P. L., 233.Spark, A. H., 275, 282.Sparks, J., 174.Spatz, S. M., 219.Speakman, J. B., 157.Speakman, J. C., 333.Speck, J. F., 266.Spencer, C., 124, 199.Sperber, E., 243.Spero, G. B., 204.Spielman, M. A., 211.Splitter, J. S., 129.Spoor, H. J., 341.Spring, F. S., 122, 124, 214.Sprinson, D. B., 244, 250.Sproul, E. E., 242.Srivastava, L. N., 111.Stabel, W., 13.Stace, H. C. T., 329.Stacey, G.J., 138.Strtcey, M., 299, 301.Stadler, H. P., 106.Stadtman, E. R., 260.Stamm, H., 105, 106.Stanck, J., 211.Stanley, W. M., 35, 314.Ytarr, D. D., 116.Staudinger, H., 119, 162,163, 164, 165, 166, 168,170, 171, 172, 173, 208.Stauff, J., 44, 45, 46.Staveley, L. A. K., 52, 58.Steacie, E. W. R., 19, 51,53, 58, 59, 60, 139.Stearns, R. 8., 40, 47.Steger, L., 214.Stehle, R. L., 310.Stein, G., 30, 159.stein, W. H., 271, 272, 279.lteinbach, M. M., 310.Iteinbuch, W., 234.Steiner, R., 84.Stenstrom, W., 10, 25.Stephen, J. M. L., 278, 289.Stephenson, D., 305.Stephenson, M., 265.Stepka, W., 272, 276, 278.Stepukhovich, A. D., 60.Stern, K. G., 290.Sternbach, L., 174, 176,Stetten, M. R., 250.Stevens, A. B., 189.Stevens, A.J., 97.Stevens, P. G., 195.Stevens, T. S., 214.Stevenson, J. K., 159.jteward, F. C., 272, 278,Stewart, F. B., 16, 25.Stewart, K., 99.kewart, R., 125.jtjernholm, R., 243.Stock, J. T., 333, 334.itoddart, E. M., 54.itodola, F. N., 299.177, 178.325INDBX OF AUTHORS’ NAMES. 359Stokes, J. L., 231.Stokland, K., 96.Stokstad, E. L. R., 226,227, 229, 230, 231, 233,237.Stone, H. W., 333.Story, R. V., 321.stott, v., 334.Strachan, S. J., 306.Strafford, N., 325.Strain, W. H., 257.Strecker, H., 261.Street, H. R., 10.Strivens, M. A., 90.Strock, L. W., 321, 324.Studier, M. H., 116.Sturgis, B. M., 216.SubbaRow, Y., 222, 223,226, 227, 229, 230, 231,233, 237.Suckfull, 2 13.Sue, P., 84.Suess, H. E., 83.Sullivan, W.N., 173.Sully, B. D., 332.Sulman, F., 302.Surgenor, D. M., 59, 146.Suter, C. M., 137.Suter, E.; 307,Suter, H. S., 85.Sutherland, G. B. B. M.,100, 276, 287.Svedberg, T., 284.Sverdrup, H. U., 338.Swank, H. W., 341.Swarm, S., jun., 107.Swanton, A., 189.Sweeney, T. R., 198.Swern, D., 135.Swift, E. H., 332, 337.Swift, H. F., 299.Swift, P. N., 306.Sykes, P., 208.Sylvester, R. F., jun., 233.Synge, R. L. M., 267, 268,269, 270, 271, 273, 274,276, 279.Szebellkdy, L., 336.Szsgho, F., 333.Szpilfogel, S., 205.Szwarc, M., 60, 61.Ta, Y., 83.Takvorian, S., 115.Tallichet, A., 186.Tamarelli, R. M., 268.Tanford, C., 59.Tarbell, D. S., 192, 194,Tarbutton, G., 101.Tardy, P., 101.Tartar, H. V., 38, 50.Tarver, H., 241.Tattersfield, F., 173.Tauch, E.J., 106.Tauring, A., 196.198.Taylor, A. H., 52.Taylor, E. C., jun., 233,Taylor, H. A., 57, 59.Taylor, H. S., 20, 22.Taylor, J. K., 334.Taylor, L. S., 13.Taylor, M. C., 332.Taylor, M. D., 93.Tchakirian, A., 97, 109.Teller, E., 55.Teorell, T., 341.Terem, H. N., 89.Terentiev, A. P., 126.Terentieva, E. A., 115.Terjessen, S. G., 270.Tesar, C., 246.Tesluk, H., 279.Thamer, R., 102.Thanheiser, G., 326.Thelin, J. H., 106.Theobald, H., 23.Theodorof, P., 6.Thode, H. G., 85, 92.Tholin, G., 113.Thomas, C. C., 292.Thomas, E. W. P., 313.Thomas, H., 263.Thomas, H. C., 268.Thomas, L. F., 116.Thomas, R. M., 297, 300.Thompson, D. L., 302.Thompson, H. L., 302.Thompson, H.W., 77, 136.Thompson, J. P., 272.Thompson, R. B., 159.Thompson, R. M., 89.Thompson, R. O., 314.Thompson, T. G., 338, 339,Thorndike, E. M., 319.Thruston, M. N., 325.Tickner, A. W., 95.Tiggelen, A. van, 21.Tinker, J. F., 205, 250.Tischer, J., 339.Tiselius, A., 269, 270.Tishler, M., 131, 236.Tiskhoff, G. H., 279.Titus, L., 339, 340.Todd, A. R., 138, 199, 203,205, 207, 208, 209, 214.Todd, D., 181.Toennies, G., 274.Tolman, L., 233.Tomkieff, S. I., 116.Tomlinson, A. J. H., 42.Tomlinson, H. M., 331.Tompkins, E. R., 268.Tompkins, F. C., 88.Tompsett, R., 308.Topham, A., 208.Toscani, V., 329.Toth, S. J., 329.Tracey, A., 325.Traube, J., 41.234.341, 342, 343.Traube, W., 130, 215.Trautner, E.M., 335.Treadwell, W. D., 89, 91,Trenner, N. R., 231.Tresadern, F. H., 173.Tribalat, (Mlle.) S., 111.Tristram, G. R., 271, 276,Troitzkaja, A. D., 114.Truog, R., 329.Tscherniaev, I. I., 114.Tschurmanteeva, M. N., 97.Tsukerman, N. Y., 124.Turk, E., 334.Turnbull, D., 144.Turner, D. L., 206, 212.Turner, E. G., 196.Turner, F., 115.Turner, H. S., 313.Turner, W. J., 253, 258.Tuttle, L. C., 262.Tweedie, M. C. K., 25.Twomey, D., 312.Twort, F. W., 302, 311.Twyman, F., 316.Tyndall, A. M., 14.Tzukervanik, I. P., 136.107, 319.287.Ubisch, H. v., 246.Udenfriend, S., 276, 287.Underhill, S. W. F., 291.Ungar, J., 297, 298.Urbine, H. E., 106.Urey, H. C., 54.Urry, W. H., 138, 140, 141,146, 150, 152, 153, 160,161.Usanovitsch, M., 336.Usher, F.L., 24.Utter, M. F., 260, 265.Vajna, F. P., 85.Valentiner, S., 94.Vanas, D. W., 60.Van Cleave, A. B., 110.Van Dame, H. C., 332.Vandaveer, L., 331.Vandenbelt, J. M., 229.Van den Ende, M., 302.Van Heyningen, E. M., 167.Vanpee, M., 21, 22.Vanselow, A. P., 319.Varrallyay, G., 328.Vaughan, J. R., jun., 205.Vaughan, W. E., 59, 146,Vdovenko, V. M., 97.Velden, P. F. van, 99.Velghe, C., 22.Veltman, P. L., 56.Vennesland, B., 239, 265,266, 267.Vereschtschaguine, L. F.,114.Vermillion, G., 136.147, 148, 149360 INDEX OF AUTEORS’ NAMES.Viehweger, H., 102.Vincent, G. P., 332.Vincent, H. B., 317, 319.Vinograd, J. R., 42.Vinogradova, E. Y., 126.Vischer, E., 275, 281.Vives, J. P., 88.Voevodsky, V.V., 69, 75.Vogler, K., 199.Volcani, B. E., 244.Volmer, G., 5.Wadman, W. H., 273, 281.Wrtdsworth, K. D., 95.Waelsh, H., 241, 252.Waggaman, W. H., .98.Wagner, C. D., 335.Wahl, A. C., 117.Waksman, S. A., 307, 308.Walbank, F., 318.Waldmann, H., 176, 177.Walen, R. J., 19.Walker, H. G., 129.Walker, J., 130, 228, 236.Walsh, A. D., 59, 114.Wallace, A., 329.Wallace, G. J., 309.Waller, C. W., 226, 227,230, 231, 233, 237.Walsh, A., 317, 322.Wa.lters, W. D., 54, 60.Walti, R., 319.Walton, J. H., 105.Wamser, C. A., 93.Wandenbulcke, F., 341.Wander, I. W., 325.Wang, S. N., 58.Wannowius, H., 198.Ward, A. F. H., 39, 43.Ward, E. R., 130.Ward, R., 90.Wardleworth, J., 208.Waring, C. E., 58, 60.Waring, C.L., 318.Warren, F. L., 136.Warrick, E., 60, 63.Wartenberg, H. von, 96.Wassermann, G., 60.Waters, W. A., 51, 139, 155,Watkins, W. M., 281.Watson, E. R., 219.Watson, J. H. L., 23.Watt, D., 261.Watt, G. W., 102.Wattenberg, H., 341.Waugh, D. F., 285.Webb, D. A., 338.Webb, K. R., 109.Weber, H. C., 330.Weber, L. J., 41.Weber, W., 104.Webley, D. M., 281.Weedon, B. C. L., 134.Weedon, W., 328.Wegman, T., 290.158, 159.Wegmiiller, F., 6.Weihrich, R., 326.Weijlard, J., 236.Weinhouse, S., 96, 263.Weisblat, D. I., 235.Weiss, C., 294.Weiss, C. M., 344.Weiss, E., 290.Weiss, G., 102.Weiss, J., 25, 26, 28, 30,31, 51, 159, 268.Weisz, P. B., 16.Weisz-Tabori, E., 266.Weitzenbock, R., 186.Weizmann, M., 151.Weldon, L. H.P., 161.Weller, R. A., 279.Weller, S., 116.Wells, H. G., 292, 295.Wells, J. R., 301, 305, 310,Wells, R. A., 283.Wendt, G. L., 21.Wenker, H., 216, 219.Wenkert, E., 169.Werkman, C. H., 260, 261,264, 265, 266.Werner, A. E. A,, 114.Wertz, J. E., 55.West, J. R., 105.West, R., 259.West, T. F., 163, 164, 165,167, 169, 170, 171, 172,173.Westall, R. G., 281, 283.Westfall, B. B., 306.Westheimer, F. H., 137.Westlake, H. E., jun., 105.Wheeler, T. S., 83.Whitby, (Sir) L., 139.White, A., 283, 290.White, A. G. C., 261, 264.White, D. A., 295.White, G. N., 213.White, J. F., 332.White, L. M., 90.Whitehead, C. W., 212.Whitlock, M. H., 105.Whitman, B., 201.Whitmont, F. F., 207, 210.Whitmore, F. C., 153, 156.Wiberg, E., 86, 92, 93.Wick, A. N., 271.Wicke, E., 109.Wickert, J. N., 35.Wicks, Z. W., 86.Wiebusch, K. D., 106.Wiegmd, C. J. W., 129.Wieland, K., 91.Wieland, T., 280.Wienhaus, H., 176.Wiken, T., 261.Wilber, S., 314.Wilcoxon, F., 165, 171.Wildman, R. B., 130.Wiley, R. H., 131.315.U’ilken, J., 317.Wilkes, B. G., 35.Wilkinson, J. F., 254.Wilkinson, S., 275.Willan, A., 336.Willard, H. H., 98.Willbourn, A. H., 68, 69,70, 71, 72, 73.Willemart, A., 134.Willgerodt, C., 211.Williams, E. F., 287.Williams, G., 57.Williams, N. T., 15.Williams, R. J., 226, 272.Williams, R. J. P., 84.Williams, T. I., 267.Williamson, A. T., 67.Willis, H. S., 294.Willis, J. B., 107, 114.Willstiitter, R., 189.Wilmarth, W. K., 113.Wilson, A. N., 223.Wilson, A. S., 116.Wilson, C. L., 161, 333.Wilson, D. W., 239, 267.Wilson, E. G., 339, 340,Wilson, G. S., 304.Wilson, J., 265. .Wilson, J. N., 268.Wilson, S. H., 320.Wilson, T. L., 343.Wilson, W., 207.Windaus, A., 191, 192,Winegard, H. M., 374.Winkler, C. A., 68.Winkler, F., 259.Winnick, T., 242, 243.Winslow, A. F., 86.Winslow, E. C., 127.Winsor, P. A., 37, 38, 43,Winsor, R. V., 86.Winstein, S., 148.Winstein, W. A,, 272, 274,Winteringham, F. P. W.,Wintersteiner, O., 286.Wirth, H. E., 341, 343.Wittenberg, J., 255.Witting, R., 341.Wittwer, C., 187.Woiwod, A. J., 280, 282.Wolf, D. E., 199, 223, 232,Wolfe, R. A., 323.Wolff, J. A., 233.Wolffenstein, R., 137.Wolfrom, M. L., 201, 202,203, 204, 213, 215.Wood, H. G., 241, 243,261, 2’63, 265.Woodbine, M., 306.Woods, D. D., 302.341.194.44.275, 282.334.233Woodward, R. B., 175, 202.Woolley, D. W., 214, 289,302, 311, 313.Wooster, N., 96,Wooster, W. A., 96.Work, C. E., 278.Work, E., 278.Work, J. B., 113.Wormall, A., 301.Wormell, T. W., 100.Wormser, (Mlle.) Y., 112.Wright, G. P., 306.Wright, T. A., 317.Wuyts, H., 215.Wyatt, G. H., 333, 334.Wyckoff, H. O., 16.Wyckoff, R. W. G., 10, 82,Wyk, A. van der, 46.275, 278.INDEX OF AUTHORS’ NAMES. 361Wylie, A. W., 115, 116.Yakovlev, B., 77.Yamamoto, R., 163.Yanagami, S., 310.Yanagisawa, J. K., 310.Yanko, W. H., 123.Yankwich, P. E., 95, 212.Yavorsky, P. J., 99.Yeddanapalli, L. M., 60.Yntema, L. F., 332.Yost, D. M., 82.Youmans, A. S., 307.Youmans, G. P., 304, 307.Young, E., 309.Young, E. H. P., 309.Young, W., 331.Yuill, M. E., 301.wyss, R., 98.Zachariasen, W. H., 116.Zaffaroni, A., 279.Zahl, P. A., 7.Zander, H., 130.Zappi, E. V., 127.Zavist, A. F., 157.Zeerleder, A. von, 317, 318.Zeisel, S., 191.Zeiss, H. H., 174, 182, 183.Zeldovich, J., 65.Zetterberg, B., 312.Zomlefer, J., 217, 218.Zondek, B., 302.Zucker, G., 306.Zumbusch, M., 98.Zwicker, B. M. G., 342.Zwicky, R., 186.Zwolinski, B. J., 63.Zworykin, K., 323

ISSN:0365-6217    

DOI:10.1039/AR9484500345

出版商:RSC    

年代:1948

数据来源: RSC

摘要:

INDEX OF SUBJECTS.Abietic wid, permanganate oxidation of,structure of, 174.lzeoAbietic acid, 174.isoAbietic acid, 175.Acetaldehyde, condensation of, with vinyldeuterated, thermal decomposition of,thermal decomposition of, 52.182.cyanide, 125.53.Acetamido-acids, separation of, 276.Acetanilide, reduotion of, to cyclohexanone,Acetato-calcium chloride, 90.Acetato-lead halides, 98.Acetic acid, ally1 ester, y-acetoxybutalde-hyde from, 134.biochemical function of, 260.tert.-butyl ester, decomposition of, 60.glacial, as solvent in titrations, 335.in biosynthesis, 241.metabolism of, 260.oxidation of, by yeast, 263.preparation of, 134.reaction of, with wetyl peroxide, 140.with selenium dioxide, 159.zinc salts, 91.Acetic acid, bromo-, reaction of, withoct-l-ene, 153.chloro-, and its methyl ester, reactionof, with acetyl peroxide, 140.dichloro-, methyl ester, reaction of,with oct-l-ene, 152.chlorothiol- and thiol-derivatives, ad-dition reactions with, 154.iodoso-, phenyl ester, methylation by,of aromatic nitro-compounds, 158.oximinocyano-, ethyl ester, use of, toliberate amino-acids from their salts,132.124.Acetone, decomposition of, 58.Acetophenone, decomposition of, 58.5-Acetoxythiazoles, 209.Acetyl chloride, trichloro-, reaction of,with oct-l-ene, 152.peroxide, reactions of, 140.phosphate, 260.with allylbenzene, 161.Acetylcellulose chromatograms, 270.Acetylcholine, synthesis of, in brainN-Acetylcolchinol methyl ether, deamin-Acetylene, dimerisation of, 59.hydrolysis of, 261.extracts, 262.ation of, 195.polymerisation of, 22.reactions of, 132.reduction of, to ethylene, 123.Acetylenediureide, hydroxy-, 251.3rAcetylenic compounds, 132.N-Acetyliodocolchinol methyl ether, de-gradation of, 193.Acetylmethylcarbinol, formation of, byyeast, 264.Acetyloleanolic acid, conversion of, into/3-amyrin acetate, 205.Acetylpeptides, separation of, 276.Acid chlorides, reduction of, 122.Acid-fastness of bacilli, 297.Acids and their derivatives, 128.carboxylic, synthesis of, 134.conversion of, into alcohols by thiol-fatty, effect of aggregation on propertiesseparation of, 277.mineral, removal of, from polysac-charide or protein hydrolysates, 132.organic, separation and detection of,282.standardisation of, 331.strong, separation of, from weak acids,weak, titration of, in non-aqueousAcraldehyde, addition of methylthiol to,Acrylic acid, ethyl ester, p-carbethoxy-methyl ester, reaction of, with thiols,reaction of, with diazonium salts, 155.esters, 205.of, 50.132.solvents, 335.130.propaldehyde from, 134.154.Acrylonitrile.See Vinyl cyanide.Actinons, 115.Acylation, 129.Addition reactions, 149.Adenine, preparation of, from 2-mercapto-Adenines, incorporation of, into tissueAdenosine phosphates, synthesis of, 138.Adenylic acid, muscle, deamination-Adrenaline, separation of, 282.Adsorption on carrier material, 271.Aerobacter, acetic acid as carbon sourcefor, 260.Aerosols, 35.Aerosol I.B., critical concentration inAerosol O.T., copper and nickel salts, 36.transition to aggregated state in, 42.Air, detn.of ammonia in, 341.Agathic acid, structure of, 184.Aggregation in ionisation reactions, 17.Alanine, conversion of, into 2 : 4 : 5-adenine, 205.purines, 246.reamination of, 246.solutions of, 38.critical concentration in solutions of, 38.trimethyloxazole, 13 1INDEX OF SUBJECTS. 363p-Alanine, preparation of, 125.Alcohols, action of rays on, 22.secondary, oxidation of, to ketones, 124.Aldehyde groups, protection of, 213.Aldehydes, aromatic, preparation of, 2 14.heating of, with ammonium formate,preparation of, from thiol-esters, 204.reduction of, 122.Alepic acid, 174.Alkaloids, solanaceou8, separation of, 2 7 8.5-Alkoxyoxazoles, 2 10.Alkylation, 135.Alkylbenzenesulphonates, conductivity in3 - Alkylnaphthaquinones, 2 -hydroxy -, pre -Alkyltrimethylammonium bromides, con-Allantoin, 251.Ally1 alcohol, y-hydroxybutaldehyde from,134.Allylbenzene, reaction of, with acetylperoxide, 142, 161.Alopecia, inositol as nutritional factor in,313.Aluminium chloride, compound of, withfluoride, compounds of, with ammonia,oxide, precipitation of, from sodiumphosphide, preparation of, 93.sulphate, compounds of, with ammonia,129.solutions of, 38.paration of, 142.ductivity in solutions of, 38.ammonia, 94.hydrolysis of, 94.93.aluminate solutions, 94.93.h i d e s , preparation of, 128.Amidines, preparation of, 127, 128.Amines, aliphatic long-chain, acid-bindingproperties of, 132.aromatic, phosphorylation of, 138.potentiometric titration of, 335.synthesis of, 129.detection of, in chromatograms, 274.of insulin, 286, 287.quantitative chromatography of, 279.removal of salts from solutions of, 273.separation of, 276, 278.thiobenzoylation of, 208.titration of, in non-aqueous solvents, 336.water-soluble, preparation of, froma-Amino-acids, conversion of, intoAmino-acids, 130.their salts, 132.oxazoles, 13 1.differentiation of, 275.preparation of, 215.amino-acids, 275.D-Amino-acids, distinction of, from L-w-Amino-acids, preparation of, 128.a-Amino-esters, acylation of with S-phenyl chlorothioformate, 213.Amino-groups, protection of, 213.Aminomethylation, 136.Amino-sugars, detection of, in ohromato-grams, 274.Ammonia, decomposition of, by a-rays, 19.by X-rays in xenon, 21.detn.of, in sea water, 341.liquid, solutions of metals in, 99.oxidation of, 99.reactions of, with nitro en oxides, 99.Ammonium carbamate, fissociation pres-sure of, 99.dichromate, thermal dissociation of,mixed with ammonium sulphate, 99.fluoride, fused, electrolysis of, 101.mcjlybdate, composition of, 108.nitrite from ammonia oxidation, 99.salts, effect of ultra-violet light onsolutions of, 99.Amphipathic agents, 34.Amphiphilic property, 43.tert.-Amy1 peroxide, 146.JS-Amyrin acetate, 205.AnEmia, pernicious, separation of anti-substance for, 278.Analysis, coulometric, 336.apparatus for, 333.Anhydro-sugars, preparation of, 214.2 -Anilino-4-6-diethylamino -a-methyl butylamino - 6 -methylp yrimidine , 2 -p-chloro - , derivatives, chemotherapywith, in tuberculosis, 307.Anisole, additive compounds of, withgermanium, silicon, and tin chlorides,97.emission spectrographic, 3 16.volumetric, 330.o-substitution in, 158.Anisotropy, optical, 49.Anthocyanins, separation of, 282.Anthranilic acid, reduction of, to o-aminobenzyl alcohol, 123.Antibiotics for control of tuberculosis, 307.Antigens, artificial, against tuberclebacilli, 301.Antimonic acid, 102.Antimony pentachloride, molecular com-Antipyrine, lanthanon complexes with,Antiseptics, effect of phospholipoids onArginine, detection of, in chromatograms,Argon, liquid, ionisation of, by a-rays, 13.Arsenic, detn.of, 337.pounds of, with acid chlorides, 102.115.toxicity of, 303.274.value of W for y-rays in, 13.in sea water, 340.trihydride, liquid, density of, 102.trioxide &s volumetric standard, 332.solubility of, 102.Arsine. See Arsenic trihydride.Arsonium salts, synthesis of, 138.Aryldiazonium salts, 130.Arylfurans, 158.Arylstibonic acids, 102.Asparagus, sulphur compound from, 201.DL-Aspartic acid, 131.Atmosphere, dinitrogen oxide in, 100.helium content of, 85364 INDEX OF SUBJEOTS.Atoms, identification of, 16.Atomic energy, reports on, 84.Atomic weight of boron, 92.Atomiser, metal, 328.Auger effect, 1 1.Aziridines, 2 16.Azobenzene, solubility of, in cetyl-pyridinium chloride and in hexa-decane, 41.Azo-compounds, decomposition of, 56.Azoles, 206.Azulene, structure of, 187.BCG, vaccine treatment with, in tubercu-Bacilli, inositol synthesis by, 313.Johne’s, leprosy, timothy-grass, andleprosy and timothy-gram, acids from,timothy-grass, growth factor from, 31 1.tubercle, chemical composition of, 295.losis, 300.tubercle, 310.297.effect of acids and bases on, 303.growth inhibitors for, 312.mode of action of, 295.Bacteria, amino-acids in, 278.Bacteriophage, inactivation of, by X-rays,Barium azide, impact detonation of, 19.iron oxide, structure of, 90.titanium oxide, 90.Baudisch reaction, 137.Beef, digestion of, 279.ethanolamine- and hydroxylysine-Benzaldehyde, reaction of, with tert.-Benzene, chloromethylation of, 136.consolution of water and, by sodiumnitration of, 137.oxynitration of, 137.reaction of, with methyl alcohol ormethyl ether in presence of catalysts,135.solubility of, in cetylpyridiniumchloride, 40.Benzene, bromo-, reaction of, with n-butylmagnesium bromide, 160.Benzoic acid, reduction of, to benzylalcohol, 123.sodium salt, solubility of organicsubstances in, 41.Benzoic acid, p-amino-, antibacterialaction of, 307.o-chloro-, as volumetric standard, 330.Benzopyrylium salts, synthesis of, 133.Benzoyl peroxide, kinetics of decom-position of, in solvents, 143.reaction of, with ethers, 143.with methyl maleate, 155.N-Benzoylcolchide, 194.N-Benzoylcolchinic mid anhydride, 194.Benzoylrhizopterin, 232.6-Benzoyl-2 : 3 : 4-triacetyl-~-arabinose,31.phosphoric acids in, 279.butyl peroxide, 148.oleate, 43.214.Benzyl chloride from chloromethylationcyanide, reaction of, with formamide,hyponitrite as polymerisation catalyst,sulphide, reaction of, in ethanol withof benzene, 136.127.158.Raney nickel, 199.one, 210.2-Benzyl-4-hydroxymethylenethiazol-5-Benzylideneazine, decomposition of, 57.4 - Benz ylidene thiazolone, 2 0 9.2-Benzyl-4-p-methoxybenzylthiazol-5-one,Benzylpenicillin, structure and stereo-Benzylpenillamine, synthesis of, 209.p-(Benzylsu1phonamido)propionic acid,Beryllium carbonate, bwic, dissociation209.chemistry of, 200.125.of, 89.hydride, 122.nitrate, dissociation of, 89.sulphate, dissociation of, 89.sulphide, preparation of, 89.tetracyanonickelate, 114.Biological extracts, flame photometryBiosynthesis, function of small moleculesBiotin, stereoisomers of, 220, 22 1.&Biotin, 220.structure of, 199.(&)-Biotin, 223.(f)-epiBiotin, 221, 224.( f )-epialloBiotin, 223.Bismuth, preparation of bismuthetes from,Bismuth triiodide, reaction of, withBlood, haemin isolation from, 259.spectrographic analysis of, 325.taurine in, 279.Blood-corpuscles, red, hzmoglobin syn-thesis in, 259.Blood group A substance, 281.Borax, pH of O - O ~ M ., 333.Borazene derivatives, dimerisetion of, 93.Borazine derivatives, trimerisation of,Borazole, and its derivatives, 93.Boric acid, detn. of, volumetrically, 336.Boron, atomic weight of, 92.isotopes, 92.detn.of, 330.fluoride ammoniates, 93.nitride, 93.with, 329, 330.in, 239.103.sodium in liquid ammonia, 102.93.as catalyst in ketone synthesis, 129.BouveaultBlanc reaction, 123.Brain extracts, acetylcholine synthesis in,Bremstrahlung, 11.Bromine, colour of, at low temperatures,genera.tion of, in coulometry, 337.Bromoform, addition reactions of, 151.262.110INDEX OF SUBJECTS. 365Buffers added to partition chromatograms,Buffer solutions as pH stmdards, 333.Burettes, 333, 334.Butadiene from vinylacetylene reduction,sulphone. See 2 : 5-Dihydrothiophenvinyl cyanide addition to, 126.n-Butane, decomposition of, 58, 59.isoButane, decomposition of, 60.tert.-Butyl hydroperoxide, 146.peroxide, kinetics of pyrolysis of, 146.reactions of, 145.n-Butylmagnesium bromide, reaction of,with bromobenzene, 160.8- and 9-D-araboButylpteridines, 2-amino-6 -hydroxy - 8- and - 9 -tetrahydroxy -,235, 236.Butyric acid, a-amino-, in animal andplant extracts, 279.y-amino-, in potatoes, 279.isoButyric acid, dichloro-, preparationof, from l-methylallyl cyanide, 125.p/3’-dimercapto-, 20 1.isoButyrophenone, Willgerodt-Kindler re-action with, 213.isoButyry1 chloride, reaation of, withacetyl peroxide, 140, 141.Cadaverine from pentamethylene dibro-mide, 130.Cadmium hexachloroaurate, 89.270.124.1 : 1-dioxide.hydroxide, precipitation of, 91.iodide, thermal dissociation of, 91.sulphates, basic, 9 1.tetracyanonickelate, 114.fluoride vapour &s mineraliser, 96.hydrogen fluorides, 86.hydroxide, cell for preparation of, 86.rhodium chlorides, complex, 115.Calciferol, effect of, on tuberculosis, 313.Calcification in caseous areas, 294.Calcium aluminate, 90.Czesium chloride, reaction vessels coatedwith, 68.carbonate, thermal decomposition of,detn.of, 330.hydride, preparation and industrialuses of, 89.hydroxide, chlorination of, 89.oxides, 89.phosphate carbonates, complex, 90.89.Calculators for emission spectrography,Carbohydrates, chromatographic separ-detection of, in chromatograms, 274.Carbon, combustion of, in sir, 95.comparison of, with silicon, 96.detn. of, in sea water, 343.isotopes, 94, 95.fluorides, 95.319.ation of, 281.Carbon tetrachloride, reaction of, witha- and /3-naphthoyl peroxides, 141.Carbon halides, addition reactions of, withethylenic compounds, 150.preparation of, 96.solution of, in ammoniacal copper (I)use of, in organic synthesis, 134.dioxide, assimilation of, heterotrophic,reduction of, to methyl alcohol, 123.utilisation of, by animals, 267.in biosynthesis, 239, 265.Carbonyl chloride, synthesis of, 2 1.monoxide, oxidation of, 2 1.chloride, 87.266.chlorofluoride, 96.cyanide, 96.halides, 96.selenide, 96.telluride, 96.Carbonylatioii, 133.3-Carboxy-6-methylpyrazine, 2-amino-,236.Carboxypeptidase, irradiation of solutionscontaining, 25.Car-3-ene, oxidation of, 163.Caseation, 293.Casein, digestion of, 279.Catalysts for acetylenic reduction, 123,for addition of carbon monoxide, 134.Cedar wood, constituents of, 189.Cells, electrochemical, Castner-Kellner,124.86.laboratory, 109.photo-electric, multiplier, 383,Cellulose from marine algze, 281.Cement, spectrographic analysis of, 325.Cepharanthine, chemotherapy with, 309.Cerium oxides, 115.Cetylpyridinium chloride, conductivity insolutions of, 39.solubility of szobsnzene in, 41.solubility of benzene in, 40.micelle, radius of, 49.Chains, initiation of, in reactions, 73.Charge neutralisation, 15.Chaulmoogra oil, treatment with, ofChaulmoogric acid, structure of, 314.Chelate compounds, synthetic, 113.Chloramine-T, 3 32.Chlorella, chromatography of photo-synthesis by, 275.Chlorine fluorides, 109.N-Chloroamides, catalytic action of, 155.Chlorocobalt ( + 1) trichlorocobaltate, 112.Chloroform, addition reactions of, 151.irradiation of, 22.titrations of alkaloids in, 335.Chloromethylation, 136.Cholesterol, biosynthesis of, 262.fatty-acid excretion after feeding on,Choline, detection of, in chromatograms,leprosy, 3 14.isotopes, 110.dioxide, preparation of, 110.314.275366 INDEX OF SUBJECTS.Choline-esterase, fluorophosphonates asChroman derivatives, synthesis of, 125.Chromatograms, paper, detection of sub-Chromatography, partition, 26 7.inhibitors of, 139.stances on, 273.apparatus for, 272.in inorganic chemistry, 84,principles of, 268.complexes, 107.trioxide, oxidation by, 169.reduction of, by hydrogen, 107.reduction of acetylene, 123.iodide, hydrazine complexes of, 107.107.sulphate, green and violet, 107.partition, 269.Chromium, electrodeposition of, fromChromium(I1) chloride as catalyst inChromium(II1) chloride, green and violet,Chromobacterium iodinum, dye from,Chrysanthemumcarboxylic acids, 163.Chrysanthemum cinerariifolium, 162.Chrysanthemumdicarboxylic acid, struc-ture of, 172.Chrysanthemummonocarboxylic acid,structure of, 171.Chymotrypsin, insulin digestion with, 290.Cinchona alkaloids, titration of, in chloro-form, 335.Cinerins, formulae of, 162.Cinerolone, 163, 167, 171.Cinerone, 17 1.Cinnamic acid, reduction of, to 3-phenyl-propyl alcohol, 123.Cinnamyl chloride, reaction of, withGrignard reagents in presence ofcobalt chloride, 161.Citraconic acid, reaction of, with diazon-ium salts, 155.Citrulline, 252.Clays, montmorillonite, hydration of, 45.Cbstridiurn butylicum, co-enzyme A in,262.Clostridium cylindrosporurn, breakdownof uric acid by, 252.Clostridium kluyveri, acetyl phosphatefrom reactions of, 260.$luster t h y y , 18.Clusters in gases, 14.Coating of reaction vessels, 68.Cobalt compounds, complex, 113.hydride, 111, 112.Cobalt(I1) chloride solutions, 112.hydroxide, oxidation of, 112.Co-enzyme A, 262.Colchiceine, 19 1.Colchicine, and its derivatives, 187.isocolchicine, 191.Colchinol methyl ether, oxidation of, 194.Combination reactions, 27.Comets, carbon isotopes in spectra of, 94.311.biological effects of, 190.oxidation of, 194.structure of, 194.Complex anions, cryscopy with, 108.Compounds, complex, stability of, 84.Compton scattering, 11.Co-ordination compounds, 82, 83.Copal.See under Rasins.Copper arsenates, 86.osrbonyl, attempt to prepare, 87.chromates, 88.compounds, chelate, stability of, andtheir reduction in pyridine, 84.detn. of, in sea-water, 344.oxidation of, 86.pyrophosphates, ethylenediamine com-sulphides, 86.Copper(1) chloride, ammoniacal solution,cyanide, complex nature of, 87.hydroxide, structure of, 86.salts, 86.Copper(I1) chloride, solutions of, 87.nitrites, hydrated, 88.salts, basic, 87.Corynebacterium, fermentation factor incultures of, 229.Coulometer, hydrogen-oxygen, 337.Coulometric analysis, 336.Coulometry , 3 3 6.Creatine, chromatography of, 282.Creatinine, chromatography of, 282.detection of, in chromatograms, 274.Crotonaldehyde, reduction of, to crotylalcohol, 123.Crotonic acid, ethyl ester, ethyl 8-formyl-butyrate from, 134.Cryptomeria japonica, cryptopimaric acidfrom, 180.Cryptopimaric acid, 180.Cryptopinone, 180.Cyanides, preparation of, 126.dicyanides, reduction of, 128.Cyanoethylation, 124.Cyanogen chloride, 110.treatment of acids or salts with, 127.Cyclotron, 6.D.F.P.See Diisopropyl fluorophos-phonate.Dacrydium biforme and kirkii, acids from,180.Deaminocolchinol methyl ether, 193.Deaminocolchinol methyl ether, iodo-,degradation of, 194.LsoDeaminocolchinol methyl ether, 193.Deaminorhizopterin, 232.Deaminoisoxanthopterincarboxylic acid,cis-Decalin, structure of, 183.Dehydroabietane, 6-hydroxy-, 182.Dehydroabietic acid, 176.structure of, 182.Dehydroabietinol, 6-hydroxy-, cestrogenicactivity of, 182.Dehydroperillic mid, 189.8-Deoxy-~-allitol, 203.plexes with, 88.solution of carbon monoxide in, 87.reaction of, with formaldehyde, 128.234INDEX OF SUBJECTS.367Deoxycholic acid, adsorption propertiessodium salt, transition to aggregatedand structure of, 42.state in, 42.l-Deoxy-D-gahbotitol penta-acetate, 203.Deoxyhexoses, synthesis of, 203.Deoxypentose, synthesis of, 203.Deoxy-sugar alcohols, synthesis of, 202.Dethiobenzylpenicillin, 200.Dethiobiotin methyl ester, 199.Dextropimaric acid, structure of, 178.isaDextropimarina1, 180.Diacetyl, pyrolysis of, free radicals from,Diamond, structure and synthesis of, 95.Di-tert.-amyl peroxide, decomposition of,Diszo-compounds, aromatic, aryl radicalsfor polymerisation, 157.Diazomethane, methylation with, 135.reaction of, with phenyl isocyanate,Diazone, chemotherapy with, in tuber-Diazonium salts, reaction of, with oleflnicDibenzcyclohepta-3 : 5-dienes, 196.Dibenzcyclohepts-1 : 3 : 5-trienes, 195.Dibenznorcaradienecarboxylic acid, 198.Dibenztropolone, 197.3 : 6-Dibenzyl-1 : 2 : 4 : 5-tetrazine, 208.Di-tert.-butyl peroxide, decomposition of,NN’-Di-n-butylurea, 201.Dicarbonyl copper(1) bromide andn- and iso-Dicinnamyls, 142, 143.Dicobalt octacarbonyl as catalyst, 134.Dideuteracetylene, polymerisation of, 22.p-Dideuterobenzene, 161.Diethylamine, di-2-cyano-, 126.Diethylamine, di-2-cysno-, 126.NN-Diethylbenzylsulphonamide, NN-di-Diethyl cellosolve.See Ethylene glycolDiethyl ether. See Ethyl ether.Difluorenyl trisulphide, structure of, 201.Digermane, decomposition of, 60.Diguanidines, synthesis of, 215.aa’-Di-n-heptylsuccinic acid, half-ester,Dihydroabietic acids, 177.Dihydrocinerolone, 167.Dihydrocinerone, 167.Dihydroglyoxalines, synthesis of, 127.Dihydropimaric acid, 178.7 : 10-Dihydropteridine, 228.Dihydropteroylglutaic acid, 229.Dihydrostreptomycin, chemotherapy with,in tuberculosis, 308.2 : 5-Dihydmthiophen 1 : l-dioxide, re-action of, with trichlorobromo-methane, 152.7 : 10-Dihydroxanthopterin, 228.54.60.from, 158.131.culosis, 306.acids, 155.59.chloride, 87.2-cyano-, 125.diethyl ether.chemotherapy with, 314.4 : 5-Diketo-2-benzylidene-1 : 3-dithiolan,1 : 4-Diketones, synthesis of, 141.Dimethylaminoazobenzene, criticd con-Dimethylaminobenzaldehyde as reagent2 : 3-Dimethylbutane, reaction of, withDimethyldialkylammonium salts, aggre-2 : 2-Dimethylethyleneimine, polymerisa-Dimethylgermanium oxide and sulphide,Dimethylglyoxime, metallic complexesDimethylglyoximorhodiuin polysulphides,3 : 6-Dimethylpyrazine, 2-hydroxy-, 214.Dinitrogen monoxide, decomposition of,208.centration of, in soaps, 42.for tryptophan, 274.tert.-butyl peroxide, 147.gation in, 37.tion of, 217.preparation of, 217.97.with, 85.115.by a-rays, 15.production of, 1UO.reaction, 77.dioxide, effect of, on hydrogen-oxygenon reaction rate, 52, 58.oxidation of, by nitric acid vapour,rate of decomposition of, 65.reactions of, with the halogens andpentoxide, action of hydrogen peroxideheat of solution of, in water, 100.vapour, thermal decomposition of, 65.Dinitrososulphurous acid, salts, 106.1 : 4 - Dio ctylo x ybenzene - 3 -sulphonic acid,potassium salt, 36.1 : 3-Dioctyloxybenzene-4-sulphonic acid,potassium salt, 36.cis-Diols, formation of, from ethyleniccompounds, 198.Dioxan, reaction of, with benzoyl peroxide,143.Dioxanyl radical, 155.Diphenylamine, 2-amino-, red base from,antiseptic to tubercle bacilli, 312.2 : 3-Diphenylbutane from ethylbenzene,141.2 : 3-Diphenyl-2 : 3-dimethylbutane fromisoprop ylbenzene, 14 1.Diphenyl ether, additive compounds of,with germanium, silicon, and tinchlorides, 97.s-Diphenylethylene glycol dibenzoate, 148.s-Diphenylguanidine as volumetricstandard, 331.Diphenyliodonium chloride, decompositionof, in presence of pyridine, 158.Diphenyl sulphone, hydrogenolysis of,200.Diphenyl sulphone, diamino -, antibacterialaction of, on tubercle bacilli, 305.Diphenyl sulphoxide, hydrogenolysis of,200.55.with oxygen, 54.on, 100368 INDEX OF SUBJECTS.Diphenylpropionic acid, Friedel-CraftsDiphtheria, flavin production in, 282.Diisopropyl fluorophosphonate, 139.2 : 2’-Dipyridyl in sea water analysis,Dipyrrylmethines, aldehyde synthesis of,Disilane, thermal decomposition of, 96.Distrychnidyl a5 reagent for nitrates, 342.Diterpcnes, 174.Dithiobenzoic acid, carboxymethyl ester,Dithioformic acid, storage of, as potassiumDithio-n-hexoic acid, methyl ester, thio-use of, for preparation of thioacylamido-cyclisation of, 197.344.258.thiobenzoylation with, 208.salt, 208.acylation with, 208.acids, 207.Dithionic mid, structure of, 104.2 : 5-Dithionpiperazine, 207.Dithio-oxamide in chromatography, 281.Dithiophenylacetic acid, methyl ester,thioacylation with, 208.storage of, &s potassium salt, 208.use of, for preparation of thioacyl-amido-acids, 207.00’-Ditolyl, ow’-dibromo-, condensationof, with malonic ester, 196.Dosimeters, 10.Dosimetry, 8.Drying, intensive, 54.Dyes, Turkey-red oil as solvent for, 42.Dynamic state of body constituents, 239.Earth, age of, from lead isotope abundance,Earths, rare, in filters for flame photo-Electrodes, casting technique for, 320.Electrolysis, coulometer for indicatingElement 61, 83.Embelin, 142.Emulsifying agents, 34.Emulsions, X-ray structure of, 48.Energy absorption, mechanism of, 10.97.metry, 328.for emission spectrography, 318.gas, 6.progress in, 337.activation, for nitric oxide decom-relation of, to vibration frequency,Epichlorohydrin, reaction of, with sodiumacetylide in liquid ammonia, 133.Ergosterol, inactivated, effect of, ontuberculosis, 313.Escherichia, acetic acid &s carbon sourcefor, 260.Esters, reduction of, 122.Esterification, 128.Ethane, photochemical bromination of,Ethane, 1 : 1- and 1 : 2-dichloro-, dehydro-position, 66.63.mean, to create ion pairs, 12.65.chlorination of, 60.Ethanolamine, metallic complexes with, 85.Ethers, decomposition of, 56.reaction of, with benzoyl peroxide, 143.5-Ethoxy-2-benzylthiazoline, 210.Ethyl alcohol, phosphorylation of, 138.Ethyl alcohol, 2-amino-, 2-acetyl deriv-Ethyl chloride, dehydrochlorination of,ative, 219.60.cyanide, 2-chloro-, 125.ether, decomposition of, 5 7.vinyl ether, decomposition of, 58.Ethylamine, 2-cyano-, 125.hydrolysis of, to p-alanine, 125.Ethylaminotrimethylborons, 93.Ethylbenzene, dissolved in potassiumlaurate, density of, 51.oxidation of, by air, 159.reaction of, with acetyl peroxide, 141.Ethylene, hydrogen chloride addition to,reaction of, with sulphur, 105.Ethylene, c w and trans-1 : 2-dicyano-,reaction of, with cyclopentadiene, 127.Ethylene cyanide, 125.cyanohydrin, cyanoethylation with, 125.glycol, solubilisation in, 44.diethyl ether, reaction of, withoxide, reaction of, with phosphorustrihalides, 138.Ethylenediamine, complexes of, withcopper pyrophosphates, 88.mercury(I1) complexes with, 92,Ethylenediaminoheteropolymolybdates,108.E th ylenediaminohe t eropol y tungs tates ,108.Ethylenedithiol, condensation of, with3 : 7 : 12-triketocholanic acid, 201.Ethyleneimine, polymerisation of, andindustrial uses of products, 216.preparation of, 216.reaction of, with acetic acid, 218.Ethyleneimines, conversion of, into ethyl-enediamines, 2 17.Ethyleneimine ketones, 219.Ethyleneiminyl-lithium, 219.Ethylenic compounds, addition reactionsof, with halogenomethanes, 150.conversion of, into cw-diols, 198.2-EthylethyleneimineY conversion of, into1 : 2-butylenediamine, 218.Ethylmercury phosphates, 92.Ethylpentachlorobenzene, a-brominationand 8-chlorination of, 167.Ethyltrichlorosilane, chlorination of, 156.Ethynylation, 132.Ethynyl ketones, reaction of, withEuropium, at.wt. and isotopes of, 11 5.Excitation sources for emission spectro-reaction of, with benzoyl peroxide,143.149.benzoyl peroxide, 143.trisubstituted, 217.phenols, 134.graphy, 321INDEX OF SUBJECTS. 369Explosions, limits of, in hydrogen-oxygenExplosive, from hydrogen peroxide andExplosives, mixed, nitrogen oxidation in,reaction, 70, 71.manganese dioltide, 104.65.Ferric oxide, action of chlorine on, 110.Ferrous ethylenediamine sulphate, 333.sulphate, oxidation of solutions of, byFerruginol, 182.Fertilisers, spectrographic analysis of, 324.Filters for flame photometry, 327, 328.Flame technique in spectrography, 325.Flavin adenine dinucleotide, 245.separation of, from tissues, 282.Flavins, detection of, in chromatograms,Fluorescence in chromatography, 274.Fluorides , non -me tall ic , preparat ion, pro -perties and structure of, 109.Fluorine, chemistry of, symposium, 109.rays, 31.274.isolation of, 109.perchlorate, 109.w-Fluoro-acids, cmboxylic long-chain, pre-Fluoroaminophosphine oxides, 139.Fluorophosphonic acid, derivatives, 138.Fluorophosphoric acid, 102.Formaldehyde, reaction of, with cyanides,Formaldoxime, decomposition of, 59.Formamide, reaction of, with benzylFormamides, reduction of, with RaneyFormamidines, disubstituted, preparationFormic acid, copper and silver salts,isopropyl ester, decomposition of, 60.Foods, spectrographic analysis of, 325.Foundry control, spectrography in, 326.Fruits, separation of acids from, 277.Fumaric acid, detn.of, in tissues, 277.paration of, 126.128.with insulin, 291.cyanide, 127.nickel, 124.of, from thioureas, 206.decomposition of, 87.diethyl ester, diethyl a-formylsuccinatefrom, 134.Furan, acylation of, 129.Gadolinium, at.wt. and isotopes of, 115.Galls, colouring matters of, 189.Gallium tetracyanonickelate, 114.Gas electrodes, 6.Gases, values of W for, 13.Generator, van der Graaff, 6.Germanic acid, 97.Germanium hydrides, 97.Germanomolybdic acid, 109.Germanotungstic acid, 109.~-Glucose, quinovose tetra-acetate from,Glutamic mid, detn. of, 277.masks, activated silver oxide for, 88.reactions, thermal homogeneous, 5 1.204,DL-Glutamic acid, 131.Glutathione, uptake of glycine into, 241.Glycine, condensation of, with pyruvicdecomposition of, by Diplococcusin porphyrin biosynthesis, 253.metabolic activity of, 241.oxidation of, in the body, 244.properties of, 241.Glycine oxidme, 244.Glycogen, formation of, from glycine, 243.liver, conversion of acetic and butyricGlycols, chloromethylation of, 136.1 : 2-Glycols, titrations in, 335.Glycyl-isoleucyl-valyl-glutamic acid, 289.Glyoxal tetra-acetate, decomposition of,Glyoxalines, naono- and di-mercapto-,acid, 256.glycinophilus, 244.acids into, 263.60.desulphurisation of, 206.amino-, 250.Glyoxaline-4( 5)-carboxyamide, 5(4bGlyoximocobalt(II1) polysulphides, 11 3.Gold, quantitative precipitation of, 88.Gold telluride, 89.Gomberg reaction, 157.Gramicidin S, chromatography with, 277.structure of, 279.Granulomata, tubercle-like, synthetic sub-Graphite oxide, 95.Graphitic acid, salts, 95.Grignerd reactions with lithium andmagnesium, 86.Grignard reagents, reactions of, in presenceof metallic halides, 160.Growth factors for bacilli, 311.Guanidines, synthesis of, 215.Hzem, in vitro synthesis of, 254.Haematoporphyrin dimethyl ether, pre-paration and oxidation of, 255.Haemin from blood, 259.Hzmoglobin, chromatography with, 277.synthesis of, in red blood cells, 259.Hafnium, separation of, from aluminium,Hair, medullated, amino-acids in, 278.Halogen atoms, reactions of, 155.Helium isotopes, separation of, 85.n-Heptane, decomposition of, 60.of, 51.Heterocyclic compounds, 2 16.synthesis of, 209.Hexachloroaurates, isomorphism of, 89.Hexahydrocolchiceine, 19 1.Hexahydrocolchicine, 191.Hexahydropyrethrone, 166.Hexahydro-8-triazines, 128.Hexane, solubility of, in sodium oleatecycloHexane, decomposition of, 60.stances producing, 298.98.from zirconium, 98.sources of, 85.dissolved in potassium laurate, densitysolution, 40370 INDEX OPcycZoHexane, hexachloro-, commercial,mesoHexane-1 : 3 : 4 : 6-tetrad, 203.cycZoHexene, decomposition of, 60.c ycloHex- 3 -ene, 1 -cyan0 - , 1 26.Hexcestrol methyl ether from p-methoxy-n-propylbenzene, 141.Hippuric acid, p-amino-, synthesis of, 242.Histamine, detection of, in chromato-grams, 274.Histidine, detection of, in chromato-grams, 274.Hydnocarpic acid, structure of, 314.Hydrazine, action of a-rays on, 21.detn. of, coulometrically, 336.Hydrazobenzene, hydrogenolysis of, inHydrazoic acid, action of active nitrogenHydrides, 86.Hydriodic acid.See Hydrogen iodide.Hydroborons, 92.Hydrobromic acid.See Hydrogenbromide.Hydrocarbons, aromatic, acylation of,129.catalysed gas-phme reactions of, 135.Hydrochloric acid, standardisation of,336.Hydrocyanic acid. See Hydrogen cyanide,Hydrofluoric acid. See HydrogenHydrogen, action of, on soot, 85.separation of, 278.ethanol, 199.on, 99.preparation of, 122.pyrolysis of, 60.See also Hydrogen chloride.fluoride.atoms, generation of, in water, 29.explosive combination of, with oxygen,isomerisation of, by a-rays, 20.isotopes, separation of, 86.liquid, plant for, at Oxford, 86.ortho- and para-, separation of, 85.para-, decomposition of, by a-rays, 20.reaction of, with oxygen, 67, 69.with sulphur, 105.Hydrogen bromide, addition of, to olefhicComFounds, 149.formation of, from its elements, 21.chloride, addition of, ta ethylene andpropylene, 149, 150.formation of, from its elements, 21.cyanide, cyanoethylation of, 125.rate of formation of, 65.deuteride, formation of, 21.deuterium selenide, 106.fluoride, properties of solutions of, 109.vapour, polymer structure in, 109.iodide, decomposition of, 19.formation and decomposition of, 52.formation of, from its elements, 21.peroxide in hydrogen-oxygen fl&meB, 77.in irradiated water, 28.properties of, and its detn., 103, 104.radiolysis of solutions of, 30.identification of, 16.104.3UB JEaTS .Hydrogen aelenide, photo-oxidation of,106.sulphide, decomposition of, by redi-ations, 19.effect of, on acetaldehyde decom-position, 54.oxidation of, 77.sulphides, 105.Hydrogen-fluorine torch, 109.Hydrogenolysis of organic sulphur com-pounds, 198.Hydroxyl radical, 159.detn.of, by absorption spectra, 76.generation of, in water, 29.identification of, 16.336.Hydroxylamine, detn. of, coulometrically,from ammonia oxidation, 99.Hydroxylation, 135.Hypersensitivity in tuberculosia, 293.Hypertension, amino-acids in, 278.detection of, 279.Hypochlorites, preparation of, 110.Hyponitric acid, salts, 100.Hypophosphorous acid, preparation of,Hypoxanthine, 250.Ice, action of a-rays on, 23.Indates, preparation of, 94.Indicator equilibrium displacement, 42.Indicators for titration in acetic acid, 335.Indium, organic precipitant for, 94.Indium halides, hydrolysis of, 94.trihalides, solubility of, in inorganichydroxide, precipitation of, 94.sulphates, equilibrium of formation of,94.Inorganic compounds, decomposition of,by radiations, 19.nomenclature, 82.sa.lts, separation of, by chromato-graphy, 283.Inositol, as growth and nutritional factor,313.Insecticides, fluoroaminophosphine oxidesas, 139.Insulating materials, spark technique inanalysis of, 325.Insulin, amino-acids of, 286, 287.chemistry of, 283.chromatography with, 277.digestion of, with chymotrypsin, 290.effect of detergents on, 284.heat precipitation of, 285.mol. wt.of, 284.peptides in, 279.reaction of, with formaldehyde, 291.structure of, 288.sulphate, 291.Iodic acid, 111.Iodide-coating of reaction vessels, 69.Iodine, radioactive, 110.101.isotopic, 84.solvents, 94.with keten, 290INDEX OF SUBJECTS.371Iodine solutions, colour of, 110.Iodinin as bacterial growth inhibitor, 311.Ion pairs, mean energy to create, 12.Ions, negative, 14.standard, 332.positive, identification and stability of,13.Ionisation potential data, 14.Iron, detn. of, in sea water, 343.electrolytic, &s volumetric standard,hydrides, 111, 112.oxidation of, 112.phosphates, 112.333.Isopolytungstates, absorption spectra of,Isotopes, abundance rules for, 83.use of, aa trmers in biosynthesis, 239.Jasmone, 163.Keten, reaction of, with insulin, 290.p-Keto-esters, synthesis of, 129.Ketones, aliphatic, reaction of, withheating of, with ammonium formate,reduction of, 122.synthesis of, from benzyl acylmalonates,109.acetyl peroxide, 141.reduction of, 123.129.129.Kieselguhr chromatograms, 270.Kinetics, chemical, 51.Krypton, isotope abundance of, 86./?-Lactam, synthesis of, 131.Lactobacillws casei fermentation factor,Lake water.See under Water.Lanthanons, 115.Lanthanon chlorides, 115.Lauric acid, potassium salt, density ofsolutions of, 51.Lead, reaction of, with sulphur dioxide,98.Lead oxide, oxidation of, 97.Leprosy, chaulmoogra oil treatment of,Leucine, turnover of, in liver peptide, 276.n- and iso-Leucine, detn. of, 280.Licheniformin, inhibition of tuberculosisby, 309.Limonene, reaction of, with iodoform andacetyl peroxide, 151.Lipoids, tubercle, biological properties of,297.Lipositol, inhibition of streptomycinactivity by, 309, 313.Lithium, Grignard reactions with, 86.Lithium aluminium hydride, preparationof, and its use in synthesis, 122.229.pentafluoroaluminate (-2), 98.treatment of, with sulphetrone, 306.314.carbonate, hydrolysis of, 86.trichlorocobaltate, 112.Liver, co-enzyme A in, 262.Liver extracts, acetylation mechanism in,fractions from, detected with Lacto-Lysine, conversion of, into a-amino-Macromolecules, partition ChromatographyMagnesium carbides, formation of, 89.chloride, anhydrous, preparation of, 59.dichromate, preparation of, 89.hydroxide, precipitation of, by am-sulphide, formation of, 89.Maleic acid, esters, addition reactions of,in presence of benzoyl peroxide, 154.reaction of, with diazonium salts, 155.Malonic acid, amino-, formyl derivative,ethyl ester, as intermediate in amino-acid synthesis, 131.Manganese, detn.of, in sea water, 343.Manganese carbide, hydrolysis of, withhydrogen chloride and with water,111.dioxide, compound of, with sodiumoxide, 111.Manganese(I1) hydroxide, oxidation of,112.“Maninositose ”, 313.Manool, configuration of, 186.Manoyl oxide, configuration of, 186.Mercaptals, hydrogenolysis of, 201.Mercury, detn. of, in sea water, 344.isotopes, reflux still for concentrating, 91.Mercury(1) perchlorate for ferric ironMercury(I1) bromide and chloride,262.bacillus lactis, 282.spectrographic analysis of, 325.adipic acid in the body, 276.of, 271.monia, 99.detn., 332.hydrolysis of, 91.chlorite, red, preparation of, 91.ethylenediamine complexes, 92.nitrate in nitric acid, oxynitration with,sulphides, 9 1.Mesaconic mid, reaction of, with di-Metal ammines, salts, preparation of, 85.surfaces, properties and state of, 84.Metals, oxides formed on surface of, 103.properties of, in liquid ammonia solu-separation of, by chromatography, 283.spectrographic analysis of, 324.complexes, stability of, 84.phenoxides, 85.137.azonium salts, 155.tion, 99.Metallic chlorides, anhydrous, preparationof, from the hydrated salts, 85.Methacrylic acid, methyl ester, poly-merisation of, 157, 158.Methane, bromination of, 64.Methane, trichlorobronio-, addition re-actions of, 151, 152.halogen derivatives, addition reactionsof, with ethylenic compounds, 150.mechanism of oxidation of, 18372 INDEX OF SUBJECTS.Methionine, detn.of, 280.sulphone, detection of, 278.sulphoxide, detection of, 279.synthesis of, 131.Methoxymethylchonodihydrostrj~chnone,p-Methoxyphenylacetic acid, preparationp-Methoxy-n-propylbenzene, reaction of,Methyl alcohol ths methylating agent, 135.202.of, 128.with acetyl peroxide, 141.bromide, bromination of, 64.n-butyl ether, decomposition of, 59.cyanide, hydroxy-, 126.ether as methylating agent, 135.ethyl ketone, decomposition of, 58.radical, selective action of, 141.Methyladrenaline, separation of, 282.Methylarsinatomolybdates, 108.Methylation with diazomethane, 135.3 -Methyl-:! -butylcycZopent -2 -en - 5 -olone,synthesis of, 168.Methyldioctylamine, 132.a-Methylenic groups, reaction of, withN-bromosuccinimide, 156.‘‘ 9-Methylfolic acid ”, 233.2-Methylfuran, 133.Methylhistidine in urine, 279.O-Methylhydroxylamine, reaction of, withGrignard reagents, 130.2-Methyl-1 : 4-naphthaquinone as grow&factor for Johne’s bacillus, 311.y- (2 -Methylnaphtha-3-quinonyl)butyricacid, 142.p- (2-Methylnaphtha- 3-quinony1)propionicacid, 142.2-Methyl-A2-oxazoline, 219.Methylcyclopentane, decomposition of, 60.O-Methylpodocarpic acid, reduction of, 182,O-Methylpodocarpinol, 182.9 -Methylpteridine, 2 -amino - 6-hydroxy-,2 : 6-d&ydroxy-, 236.3 -Methy lthioadenines, 9 -substituted,hydrogenolysis of, 205.p-Methylthiopropaldehyde from acralde-hyde, 130.9 -Methylxanthopterin, 23 7.8 -Methylisoxanthop terin, 23 7.Micelles, laminar and spherical, 46.‘ ‘ Micro-icebergs,” 27.Micro-organisms, carbohydrate metabol-ism of, 281.Microphotometers, 319.Minerals, spectrographic analysis of, 325.Miropinic acids, 180.Moissan, life of, 109.Molecules, small, function of, in bio-Molybdates, 108.Molybdenum-blue, formula for, 108.Molybdic acid, reaction of, in solutionwith copper, iron, or tin salts inpresence of thiocyanates, 108.237.synthesis, 239.solutions of, 108.Monazite, chlorination of, 115.Monochromators, 326.Monoterpenes, 162.Muscle adenylic acid, synthesis of, 138.Mywbacterium leprce.See Bacilli,leprosy.Mycobacterium paratubercubsk.SeeBacilli, Johne’s.Mycobacterium phlei. See Bacilli,timothy -grass.Mycobacterium tuberculosis. See Bacilli,tubercle.Mycolic acid, 297.Myelinic figures, 49.Naphthalene, chloromethylation of, 136.methylation of, 136.nitration of, 137.solubility of, in acetone-water and inNaphthalene, chloro-, chloromethylationNaphthalene-l-acetic acid, preparation of,Naphthaquinones as growth factors for/3-Naphthol, sulphomethylation of, 137.a-Naphtholbenzein as indicator in titra-a- and p-Naphthoyl peroxides, reaction of,Naphthylhydrox ylamine, nitroso -, the1 -4-p-Naphthylmorpholine, 21 1.Nativinsulin, 284.Nematospora gossypii, inositol as growthNeodymium tetraayanonickelate, 1 14.Neon isotopes, separation of, 85.Neophyl radical, 148.Neptunium, properties of, 117.Neutrons, ionisation and polymerisationNickel carbonyl, structure of, 114.Raney, &s catalyst, 198, 199.for hydrogenation, 124.hydride, 112.Nickel(I1) hydroxide, oxidation of, 112.Nicotine, detn.of, volumetrically, 335.Ninhydrin, as reagent for paper chromato-Niobates, 103.Niobium nitrides, 103.Niobium pentoxide, heating of, in hydro-Nisin, chemotherapy with, 309.Nitrates, detn. of, in sea water, 342.Nitration, 137.Nitric oxide. See Dinitrogen dioxide.Nitrilotriacetic acid, metallic complexesNitritopentamminocobalt( + 2) nitrate,Nitro-compounds, aromatic, methylatingNitrogen, active, action of, on hydrazoicparaffin-chain salts, 40.of, 136.128.bacilli, 3 11.tions in acetic acid, 335.on carbon tetrachloride, 141.lium(II1) complexes of, 94.factor for, 313.induced by, 8.grarn~, 274:gen, 103.with, 84.113.agent for, 158.mid, 99INDEX OF SUBJECTS.373Nitrogen, oxidation of, in explosive mix-Nitrogen tribromide, attempts to produce,tures, 65.101.preparation of, 99.trichloride, 1n.p. of, 101.fluorides, 100.hydrides and oxides, decomposition of,triiodide, impact detonation of, 19.organic compounds, detn. of, in seaoxides, reactions of, with ammonia, (39.by radiations, 19.water, 342.See also under Dinitrogen.catalysts, 157.Nitrosation, 137.Nitrosoacylarylamines as polymerisationNitrosyl compounds, 100.Nitrous oxide. See Dinitrogen monoxide,Nitryl chloride, action of hydrogenperoxide on, 100.Nomenclature, 82.Noradrendine, separation of, 282.Nucleotides, detection of, in chromato-separation of, by ultra-violet absorptionOctadecylpyridinium iodate, conductivitycycloOctatetrame, structure of, 187.Oct-l-ene, reaction of, with ethyl bromo-with methyl dichloroacetate or tri-with phosphorus trichloride and withwith sulphuryl chloride, 167.Oils, dissolving of, in soap solutions, 47.Olefins, conversion of, into primaryalcohols, 134.Oleic acid, conversion of, into 0 : 10-dihydroxystearic acid, 136.ethanolamine salt, adsorption of watervapour by benzene solutions of, 43.sodium salt, consolution of mixedsolubility of hexane in, 40.on, 22.344.246.grams, 275.chromatography, 281.in solutions of, 39.acetate, 153.chloroacetyl chloride, 152.trichlorosilane, 153.platinum complexes with, 114.liquids by, 43.Olivenite, 86.Organic compounds, action of radiationsOrganisms, marine, copper content of,Orotic acid as precursor of pyrimidines,Oxalato-calcium chloride, 90.Oxalato-indates, 94.Oxalic acid, silver salt, decomposition of,Oxaloacetic acid, enzymic decompositionOxaloacetic carboxylase, 265.Oxalosuccinic carboxylase, 266.Oxidising agents, irradiation of solutions88.of, 265.of, 24.“ 0x0 ” reaction, 134.Oxycolchicine, 194.Oxygen, effect of, on acetaldehyde decom-explosive combination of, with hydrogen,ozone formation from, 19.reaction of, with hydrogen, 67, 69.structure of, 104.position, 53.104.with hydrogen sulphide, 78.with nitrogen, 65.Oxynitration, 137.Ozone, structure of, 103.Ozoniser, 103.Oysters, copper content of, 344.Pantothenic acid, role of, in pyruvicPantoyltaurine, bacteriostatic activity of,Paper chromatograms, separations with,Papyrography, 268.Paraffins, dehydrogenation of, by rays, 22.Parafi-chain salts, 33.density of, 50.equilibria of, with alcohols or amines,oil, and water, 43,solubility in, 40.Paraffin oil, consolution of water and,by sodium oleate, 43.Parsley root, oxdoacetic carboxylase in,266.Partition coefficients, factors influencing,269.Penicillin, chromatography with, 277.detection of, in chromatograms, 275.separation of, 282.Penicillium stipitatum, 188.c y cZoPen t adiene , reaction of, with cis -cycZoPentadiene, hezachloro-, 96.Pentagermanic acid, 97.Pentamethylene dibromide, conversion of,cyclopentane, decomposition of, 60.Pent-2-ene, hexaldehydes from, 134.cyclopentene, decomposition of, 60.Pentenynol, 133.Peptide bond synthesis, 242.Peptides, detection of, in insulin, wool,metabolism, 262.312.278.and tram-1 : 2-dicyanoethylene, 127.into cadaverine, 130.and urine, 279.separation of, 278.Performic acid, hydroxylation by, 135.Periodic acid, and its salts, 11 1.Periodic tables, 83.Peroxides, reactions of, 140.Peroxyborates, 104.Peroxycarbonates, 104.Peroxymolybdates, 104.Peroxynitric acid, 100.Peroxy-salts, 104.Peroxytungstates, 104.Peroxyvanadates, 104,Per-rhenates, 11 1.Peyronet’s salt, 114374 INDEX OF SUBJECTS.Phagocytes, mono- and poly-morpho-nuclear, 294.Phosphorus trihydride, oxidation of, withaqueous iodine suspensions, 101.organic compounds, detn.of, in seaplatinum complexes with, 114. Phenanthrene, hydroxylation of, 198.Phenol, chloromethylation of, 136.Phenols, bactericidal properties of, inparaffin-chain salt solutions, 42.equilibria of, with soaps md water,reaction of, with ethynyl ketones, 134.Phenols, o-nitro-, preparation and pro-Phenyl isocyanate, reaction of, withPhenylacetic acid, reduction of, to 2-N-Phenylacetyl-L( +)-alanyl-~( - )-valine,Phenylalanine, detn. of, 280.DL-Phenylalanine, 13 1.Phenylalanyl-valyl-aspartyl-glutamic acid,43.perties of, 137.diazomethane, 13 1.p-nitroso -, 137.radical, 155.phenylethanol, 123.200.289.Phenylamino-acids, dinitro-, separationPhenylazo-p-naphthylamine, solubility of,Phenyl benzyl sulphone, vinyl cyanide/$Phenylcysteine,, preparation of, 2 16.Phenyldimorpholinomethane, 21 1.Phenylethynyl bromide, reaction of, withGrignard reagents in presence ofcobalt chloride, 161.Phenylglyoxylic acid, reduction of, tophenylethylene glycol, 123.1 -Phenylpropane, 3-chloro-, reaction of,with Grignard reagents in presenceof cobalt chloride, 160.Phenylpyridines, 158.5-Phenylpyrimidine, 4-amino -, 127.Phenyl 2-thienyl ketone from thiophen,129.Phenylthioacetamidoacetic acid, methylester, 207./3-Phenylisovaleraldehyde, reaation of,with tert.-butyl peroxide, 145.Phenylviaylmethyl radical, 161.Phosphates, absorption spectra of, 109.Phosphatides, brain, inositol in, 313.Phosphine. See Phosphorus trihydride.,Phosphomolybdic acid, 109.:Phosphoric acids, 101.Phosphoroclastic reaction, 265.Phosphorous . acid derivatives, platinumcomplexes with, 114.Phosphorus, colourless and red, 101.Phosphorus trichloride, addition reactionsof, in presence of peroxides, 153.chlorides, addition of, to organic com-pounds, 138.halides, oxy- and sulpho-halides, 102.of, 277.in soap solutions, 42.addition to, 124.properties of, 142.detn. of, in sea water, 338.from tubercle bacilli, 296.nitrogen compounds of, 102.- water, 339.reactions of, 138.oxydichlorofluoride, reactions of, withalcohols, amines, phenols, and thiols,138.Phosphorylation, 138.Phosphotungstates, spectra and stabilityPhosphotungstic acid, 109.Phospho- 12-vanadate ion, degradation of,Photocells, multiplier, 323.Photo-electron multipliers, 323.Photographic emulsions, effect of ultra-violet light on, 321.plates, calibration of, 320.Photometer, flame, 326.Photometry, flame, 326.Photons, high-energy, absorption of,Phthalic acid, dimethyl ester, solubilityPhthiocol, antigens from, 302.as growth factor for Johne’s bacillus,Phthioic acid, 297.Pigments, petal-extract, detection of, inPimanthrene, 178.Pimaric acid, permanganate oxidation of,Pinus palustris, analysis of oleoresin from,Plankton, detn.of phosphorus in, 340.Plants, spectrographic analysis of, 324.Platinum compounds, complex, 114.pure, preparation of, 114.Plutonium, properties of, 117.Podocarpic acid, structure of, 180.Podocarpinol, mstrogenic activity of,Podocurpus ferrugineus resin, 180.Pollen, amino-acids in, 278.Polonium isotope in Roumanian minerals,a-rays from, 6, 16.Polyethyleneimine; 2 17.Polygalitol, synthesis of, 203.Polymerisation, catalysts for, 157.mechanism of, 139.radiochemical, 22.Polymixin, chromatography of, 279.detection of, in chromatograms, 276.Porphyrins, biosynthesis of, 253.detection of, in chromatograms, 274.formation of, from pyrroles, 257.Positron-electron pairs, 11.Potassium, comparison of, with sodium,detn.of, 327, 329, 330.Potassium bismuthate, 103.of, 109.103.11.of, in paraffin-chain salts, 41.311.chromatograms, 274.182.structure of, 179.174.182.107.86INDEX OF SUBJECTS.378Potassium tetraborate, reaction vessel2carbonate, hydrolysis of, 86.chloride, reaction vessels coated withhydride, dissociation pressure of, 86.iodide as volumetric standard, 332.iodoplatinate as reagent for sulphurparaperiodate as volumetric standardrhenium iodate, 11 1.coated with, 69.68.containing amino -acids, 2 74.330.Potatoes, amino-acids in, 278.Proabietic acid, 174.Prodigiosin, 258.Proline, biosynthesis of, 243.Promethium, 83.Promin, antibacterial action of, orPromizole, chemotherapy with, in tuber.Prontosil rubrum, chemotherapy withPropaldehyde, decomposition of, 58.cycZoPropane, isomerisation of, to propyl.cycZoPropenone, 133.Propionic acid, tert.-butyl ester, decom-Propionic acid, a/3-dichloro-, preparationPropyl chlorocarbonate, decomposition of,isoPropylbenzene, reaction of, with acetylwith Grignard reagents in presenceRF value for, 273.tubercle bacilli, 305.chemotherapy with, 293.culosis, 306.305.ene, 57.position of, 60.of, 125.60.peroxide, 141.of cobalt chloride, 161.Propylene as retarder of reactions, 58.e f h t of, on reaction rate, 52.hydrogen chloride addition to, 150.vapour, solvents for, 42.n-Propyltrichlorosilane, chlorination of,Protamme-zinc-insulin, mol.wt. of, 284.Proteus rnorganii, co-enzyme A in, 262.Protons, spectra of light emitted fromProtoporphyrin methyl ester, 255.Pteridine, 2 -mereapto -, 2 34.Pteridines, preparation of, 233.156.pyruvic metabolism by, 262.beams of, 16.6 : 8 : 9-trihydroxy-2-mercapto-, 234.reduced, 228.synthesis of, from diaminopyrimidinesPteridine- 8-aldehyde, 2-amino - 6-hydroxy-,Pteridinecarboxylic acids, aminohydroxy-,Pteridine- 8-carboxylic acid, 2 -amino - 6 -Pterins, 226.detection of, in chromatograms, 274.separation of, 282.and sugars, 234.229.234.hydroxy-, 230.N-[ y- (y'-Pteroamido.y '-carboxybutyr-N - (a-Pteroamido-y-carboxybutyryl) -N - ( y -Pteroamido- y-carboxybutyryl) -Pteroic acid, ethyl ester, preparation of,Pteroylaspartic acid, antagonist to vita.Pteroylglutamic acid. See Vitamin-Bc.P tero ylglutamic acid, 0 -amino -, antagonistto vitamin-Bc, 233.Pteroyl-L-glutemic acid, 230.Pteroylglutamyldiglutamic acid, 230.Puberulic acid, 188.Puget Sound, detn.of nitrogen in waterPurines, biosynthesis and metabolism of,detection of, in chromatograms, 275.synthesis of, 215.Purpurogallin, 189.methyl ether, 190.oxidation of, in air in presence ofamido)- y-carboxybutyryl]glutamicacid, 231.glutamic acid, 230.glutamic acid, 231.228.synthesis of, 228.min-Bc, 233.of, 343.245.alkali, 190.Purpurogallincarboxylic acid, 190.Purpurogallone, 189.isoPurpurogallone, 189.Pyramidon, lanthanon complexes with,Pyrethrins, and their derivatives, 164.Pyrethrolone, 163, 169, 170.Pyrethrum flowers, insecticidal con-Pyridine-aldehydes, 214.Pyridinocopper( + 2) perchlorate, dis-sociation pressures of, 88.Pyridinoheteropolymolybdates, 108.Pyridinoheteropolytungstates, 108.Pyrimidine, 5 : 6-diamino-4-hydroxy-, pre-115.formulz of, 162.stituents of, 162.paration of, 205.4 : 5-diamino-2-mercapto-, 234.Pyrimidines, synthesis of, 2 15, 245.Pyrimidines, 4 : Ei-diamino-, pteridine syn-Pyrimidine-aldehydes, 2 14.Pyrogellol, oxidation product of, 189.Pyrophosphoric acid, hydration of, 102.Pyrrolos, formation of porphyrins from,Pyruvic mid, condensation of, withmetabolism of, by Proteus rnorganii, 282.reaction of, with phosphoric acid, 266.thesis from, 234.257.glycine, 256.Pyruvoylglycine, properties of, 256.auartz, synthetic, 96.auinodiphenone, 196.auinoline derivatives, synthesis of, withauinoline , 8 -h ydrox y - , thallium (111)ethyleneiminyl-lithium, 2 19.complexes of, 94376 INDEX OF SUBJEUTS.Quinoline-aldehydes, 2 14.Quinones, alkylation of, with acyl per-Quinovose tetra-acetate, synthesis of, 204.Radiation, sources of, G .Radiation chemistry, 5.Radicals, free, chemistry of, 139.identification of, 16.Radical-addition reactions, 149.Radical-addition rule, 149.Radical transfer in biosynthesis, 340.Itadiochemical reactions, addition, 2 1,oxides, 142.formation of, by means of rays, 159.indirect, kinetics of, 31.mechanism of, 5.Hadio-elements, a-rays from, 6.Radio-isotopes, use of, in partitionchromatography, 275.Radish seed, sulphoraphen from, 201.Radium, y-rays from, 8.Radon and its decay products, 6." seeds," 7.Rapanone, 142.Raphanus sativa var.alba, 201.Rate constant, first-order, calculation of,Rays, action of, on water, 23.62.cathode, 7.ionising, 5.spectra of, 16.positive, 6.a-Rap, dose rate for, 9.sources of, 6./3-Rays, dose rate for, 9.sources of, 7.y-Rays, absorption of, 12.dose rate for, 9.effect of, on water, 18.sources of, 7, 8.dose rate for, 9.inactivation of biologically active sub-stances by, 31.sources of, 7, 8.Reactions, addition, 149.branching-chain, 67.chain, intermediates formed in, 80.kinetics of, 64.first-order, 54.homolytic, 139.induced by ionising radiatione, 5.second-order, 52.third-order, 54.unimolecular, theory of, 61.X-Rays, action of, on water and solutions,25.Reaction vessels, coated, 68.Recombination reactions, 27.Reducing agents, irradiation of solutionsof, 24.Reduction, 122.Resins, copal, agathic acid from, 184,Resin aeids, separation of, 174.Resorcinol, detn.of, volumetrically, 336.dioctyl ether sulphonate, interfacialtension of, against non-polmliquids, 36.Retention analysis, 280.Rhizopterin, 231.apoRhizopterin, 231,Rhodamine, uses of, in syntheses, 215.Riboflavin and its phosphate, separationRibonuclease, inactivation of, by X-rays,Ribonucleosides, separation of, 282.aldehydo-D -Ribose tetra-acetate, 204.Roccellic acid, chemotherapy wit,h, intuberculosis, 314.Rubber, thio-acid adducts of, 154.Rubeabietic acid, 175.Rubeanic acid. See Dithio-oxamide.Rubidium hydroxide, cell for preparationS.L.R.factor, 231.Salicylaldehyde, cyanoethylation of, 125.Salicylic acid as volumetric standard, 330.chloromethylation of, 136.detn. of, volumetrically, 336.sodium salt, solubility of organic sub-Salicylic acid, p-amino-, bacteriostaticSampling, 3 19.Sapietic acid, structure of, 176.1-Sapietic acid, 176.a- and y-Sapinic acids, 175.Sea water. See under Water.Sebacic acid, reduction of, to decane-1 : 2-diol, 123.Selenitomolybdates, 108.Selenium dioxide, structure and vapourpressure of, 107.Serine, biosynthesis of, 242.Sclareol, configuration of, 186.Shiga polysaccharide, 28 1.Silica chromatograms, 269, 276.Silicates, detn. of, in sea water, 341.Silicomolybdic acid, 109.Silicon, comparison of, with carbon, 96.Silicon tetrachloride, synthesis and hydr-of, from tissues, 282.31.of, 86.stances in, 41.effect of, 306.olysis of, 97.chlorides, plastic, 97.compounds, chlorination of, 156.tetrafluoride, absorption of, by acids,and its hydrolysis by water, 97.fluoroisocyanates, 97.Silicotungstic acid, 109.Silver acetylides, 88.chromates, 88.cyanide, complex nature of, 87.hydroxide as volumetric standard, 33 1.oxides, active, preparation of, 88.Soaps, effect of aggregation on propertiesequilibria of, with phenols and water,X-ray diffraction patterns of, 44.Soap curd suspensions, optical aniso-Soap-like substances, structure of solutionsof, 50.43.tropy in, 49.of, 33INDEX OF SUBJECTS.377Soap solutions, dissolving oils in, 47.solvent power of, 42.structure of, 33.Sodium, comparison of, with potamium,86.Sodium acetylide, remtion of, withepichlorohydrin in liquid ammonia,133.azide with iodine as reagent for sulphur-containing amino-acids, 274.benzylpenicillin,.products from, heatedwith Rmey nickel, 200.bismuthate, 103.bismuthide, 103.carbonate, anhydrous, preparation of,chlorite as volumetric standard, 332.hydride, reduction with, 123.hypochlorite solutions as volumetricstandard, 332.hyponitrite, preparation and propertiesof, 100.manganates, 1 1 1.molybdate, solutions of, 108.dioxide, 86.phosphates, review, 101.thiosulphate solutions, stabilisation of,detn. of, 329, 330.331.hydrolysis of, 56.331.Soils, spectrographic analysis of, 324.Solubilisation, 40.Solubility in paraffin-chain salt solutions,Solutes, radiochemical transformation of,Solutions, concentrated, organisation in,Solvents, non-aqueous, titration in, 334.Soot, action of hydrogen on, 95.Spectra, direct measurement of lineultra-violet, for identification of atoms40,29.44.intensities in, 323.and radicals, 16.Spectrographs, direct-reading, 323.Spectrographic analysis, emission, 316.Standards for volumetric analysis, 330.Stannane from stannous chloride, 97.Stannous chloride, reduction of, byatomic hydrogen, 97.Starch chromatograms, 270.Starch, structure of, 281.Stem, rate of formation of, 72.Stearic acid, reduction of, to octadecanol,Steel, spectrographic analysis of, 326.Stercobilin, 259.Stibonium salts, synthesis of, 138.Stilbmstrol, methylation of, with diazo-methane, 135.Stipitatic acid, 187, 188.Streptidine, 308.synthesis of, 215.Streptobiosamine, 308.Streptomycin, chemotherapy with, in123.tuberculosis, 307.Streptomycin, chromatographic separationdetection of, in chromatograms, 274.inhibition of activity of, by lipositol,separation of, 282.structure of, 202.treatment of tuberculosis with, 293.Streptomycin A and B, constitution of,Strontium hexanitritocobaltate( - 3), 90.Styrene, hydrotropaldehyde from, 134.Succinic acid, preparation of, fromSuccinimide, N-bromo-, reactions andSugars, methylsted, separation of, 277,preparation of my1 derivatives ofaldehydo- or keto-forms of, 213.pteridine syntheses from diamino-pyrimidines and, 234.Sugar alcohol 1 : 5-anhydrides, 203.Sulphamic acid as volumetric standard,330.preparation of, 106.Sulphe trone , chemotherapy with, 2 93,Sdphitomolybdates, 108.Sulphomethylation, 137.Sulphones, aromatic, vinyl cyanide addi-Sulphonyl chlorides, preparation of, 157.Sulphoraphen, constitution of, 201.Sulphur, deposition of, from solutions inof, 271.309, 313.307.polymerisation of, 7, 157.hydrogen cyanide, 125.uses of, 155, 156.281.306.tion to, 124.sunlight, 105.with ethylene, 105.properties of, 109.equilibria of forms of, 104.reaction of, with hydrogen, 105.Sulphur hemfluoride, preparation andfluorides, 106.halides and nitrides, 105.organic compounds, reactions of, 198.monoxide, 79.oxy-acids, 106.oxychlorides, 104.standardisation of, 336.Sulphuric acid, removal of nitrogen from,Sulphuryl chloride as peroxide-catalysedSurface-active agents, fluorophosphates as,Taurine in blood, 279.Technetium, chemistry of, adsorbed oncopper or rhenium sulphides, 111.Telluric acid, 107.Tellurites, 107.Tellurium, chemical properties of, 107.Temperature control in radiochemicalTerbium, at.wt. and isotopes of, 115.Tergitols, 35.106.chlorinating agent, 156.102.reactions, 8378 INDEX OF SUBJECTS.Teropterin, 231.Terpenes, 162.Tetramminocopper( + 2) nitrite, thermalTetra-arylphosphonium salts, 138.Tetracalcium aluminoferrate, 90.n-Tetradecane sodium sulphate, equilibriaof, in oil-wate: mixtures, 43.sodium sulphates, critical concentrationin solutions of, 38.X-ray structure of, 44.decomposition of, 88.Tetrafluoboric acid, formation of, 93.Tetrahydroabietic wid, hydroxy-, 178.Tetrahydrofuran, decomposition of, 60.Tetrahydronaphthalene, autoxidation of,catalytic, 155, 159.Tetrahydropyrethrins, 173.Tetrahydropyrethrolone, 167.Tetrahydropyrethrone, 167.Tetrahydrostipitatic acid 2 : 4-dinitro-phenylhydrazone, 188.Tetramethyl glucose, RF value for, 273.Tetramethyltin, decomposition of, 60.Tetraailme, preparation and properties of,Thallium sulphide, 94.tetracyanonickelate, 114.Thallium(1) carbonate as volumotricstandard, 331.ferrate(III), 94.sulphate, conversion of, into sulphide,sulphoxylates, 94.ethanes, 206.mercaptothiazoles, 206.chloromethylation of, 136.96.94.Thallium(III), inner complex salts of, 94.Thianaphthens, conversion of, into phenyl-Thiazoles, prepwation of, from 2-Thiazole-aldehydes, 2 14.Thioqlamido-acids, preparation of, 207.Thioac ylat ion, 207.Thio-amides, preparation of, 207.reduction of, to amines, 207.Thiobenzaanidoacetic acid, ethyl ester,Thiobenzanilide, 208.Thiobenzhydrazide, 208.Thiobenzmorpholide, 21 1.Thiobenzophenone, trisulphide from, 20 1.Thiobenzoyl chloride, preparation andThio-compounds, addition reactions ofThiocyanates, detn.of, coulometrically,solutions, standardisation and stability207.reaction of, with aniline, 208.with olefins, 154.336.of, 332.Thiodiglycol, detn. of, 337.Thioformamides, preparation of, 207.Thiols, addition of, t o olefhic compounds,149.nickel complexes with, 114.prepwation of, 204.Thiol-esters, hydrogenolysis of, 204.Thione group in thio-amides, 206.Thion-esters, 208.Thionyl chloride, purification of, 106.chlorofluoride and fluoride, 106.Thionylimine, 106.Thiophen, acylation of, 129.aminomethylation of, 136.2-Thiothiazolidone, preparation and ayn-thetic uses of, 216.Thiourea, use of, in syntheses, 215.Thorium, analytical chemistry of, 116.Tlzuja pliwta, compounds from, 189.y-Thujaplicin, 189.Thyronine, synthesis of, 214.Titanium, preparation, properties, anduses of, 98.Titanium hydride as catdyat in selectivehydrogenation, 124.Titanous chloride as volumetric standard,332.Titration in non-aqueous solvents, 334.Tobacco, detn.of nicotine in, 335.Toluene, reaction of, with tert.-butylToluene-o-sulphonamide, reaction of vinylo-Tolylazo-/3-naphthol, soaps aa solventsTorubpsis utilis, biosynthesis by, 243.Triazens for polymerisation, 157.Trichloromethyl radical, 155.Trichlorosilane, reaction of, with oct- 1 -enc, 153.Triethylenetetramine, cobalt complexeewith, 113.3 : 7 : 12-Triketocholanic acid, condens-ation of, with ethylenedithiol, 202.Trimethylacetic acid, reduction of, toneopentyl alcohol, 123.Trimethylahminiurn, decomposition of,60.1 : 2 : 3-Trimethylbutane, diasolved inpotassium laurate, density of, 51.Trimethylcolchicinic mid, 191.N-benzoyl derivative, oxidation of, 194.3 : 12 : 15-Trimethyldocosanoic acid, 298.Trimethyloctylammonium octylsulpho-nate, conductivity in solutions of,38.2 : 4 : 5-Trimethyloxazole from alanine,131.3 : 13 : 19-Trimethyltricosanoic acid, 298.2 : 2' : 2"-Tripyridyl in sea water analysis,Trisilane, thermal decomposition of, 96.Tristhioacetophenone, 2 11.Tropolone, 187.Tryptophan, bacterial breakdown of, 279.detection of, in chromatograms, 274.Tubercle bacilli.See under Bacilli.Tubercles, origin and fate of, 292.Tuberculin, growth substances in, 31 1.Tuberculocarbohydrates, 298.Tuberculophosphat ide , 2 9 7.oxides, 98.peroxide, 147.cyanide with, 124.for, 42.unimolecular fission of, 61.344.permeability of, 293INDEX OBTuberculoproteins, 299.Tuberculosis, acquired resistance against,caseation in, 294.chemotherapy of, 292.index, 302.tests for, 303, 304.Tuberculosteaic acid, 296.Tubemulo- therapeutio compounds, po ten -tial, 310.Tungetetee, abm tion spectra of, 109.Tungsten t&uc&ide and oxychloride,108.Tungstic acids, 108.Tungstic oxide, action of chlorine on, 110.Turkey-red oil as solvent for dyes, 42.Tyrosine, detection of, in chromatograms,299.274.detn. of, 280.Unsaturated compounds, polymerismtionUranium carbides, fluorides, nitrides, andUranium(N) sulphate, 116.Uranyl nitrate, hydrolysis of, 11 7.Urea, 262.Uric mid, biosynthesis of, 240.of, under irradiation, 22.oxides, 116.in minerals, 116.breakdown Of, by Cb8tdiUm Cylindpo-8pOrmm, 262.degradation of, 247.oxidation of, 261.Uricase, 261.Urine, 6 0 - a c i d s in, 278.methylhistidine in, 279.peptides in, 279.roporphyrins, synthesis of, 268.Uroxanic acid, 261.Usnic acid, activity of, against tuberclebacilli, 312.Vaccines against tuberculosis, 300.Valine, detn. of, 280.Vanadatee, 103.Vanadium arsenides, 103.Vapoure, pyrolysis of, 66.Vessels for hydrogen sulphide-oxygenreaction, 78.for radiochemical reactions, 8.reaction, coated, 68.polymerisation of, 30, 167.preparation of, 126.Vinyl cyanide, cyanoethyletion with, 124.byrays, 169.124.Vinylacetylene, reduction of, catalytic,Vinylation, 132.IUBJECWS . 379Viruses, amino-acids in, 278.Vitamin-Bc, antagonists to, 232.catalytic hydrogenation of, 229.diethyl eater, 228.synthesis of, 227.Vitamin-K-mctive' substances, organismsaynthesisin 311.Volumetrio an$&4s, 330.apparatus for, 333.'' w-6," 199.Water, action of rays on, 23.action of y-rays on, 18.lake, detn. of dissolved nitrogen in, 342.molecules, ionisetion and excitation of,radiolysis of, 27.sea, analysis of, 338.spectrographic analysis of, 324.strueture of, 103.vapour, action of rays on, 23.26, 27.adsorption of, by ethsnolamine oleatein benzene solution, 43.Wetting agents, 34.Willgerodt-Kinder reaction, 210.Windowa, reinforced, for use. with acceler-Wool, amino-&ids in, 278, 279.atingmachines, 7.peptides in, 279.reaction of, with sulphuryl chloride, 167.boXanfhopterincarboxylic acid, 6-amino-,Xenon, decomposition of ammonia by234.X-rays in, 21.isotope abundance of, 86.Yemst, -tic acid oxidation by, 263.acetylmethylcarbinol formation by, 264.autolysis of, in preeencs of ammoniumbiosynthesis of proline and serine in,carbonate, 264.243.Zinc, detn. of, in sea-water, 343.ferri- and few-cyanides, complex, 91.hydride, 122.pure, preparation of, 90.salts, 90, 91.tetracyanonickelate, 114.dioxide, transformation of, at highprepemtion, roperties, and usea of, 98.separation o t from aluminium, 98.telluride, 99.Zirconium hydride, 98.temperaturea, 99.from hafnium, 98

ISSN:0365-6217    

DOI:10.1039/AR9484500362

出版商:RSC    

年代:1948

数据来源: RSC