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Proceedings of the Chemical Society, Vol. 19, No. 265 |
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Proceedings of the Chemical Society, London,
Volume 19,
Issue 265,
1903,
Page 119-126
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摘要:
PROCEEDINGS OF TIIE CHEMICAL SOCIETY. Vol. 19. No. 265. D.Sc.,F.R.S.,Wednesday, April 22nd, 1903. Professor W. A. TILDEN, President, in the Chair. Messrs. C. H. Lockitt, A. J. Webb, and A. H. Scholefield vere formally admitted Fellows of the Society. Certificates mere read for the first time in favour of Messrs. : Henry James Aubrey, The Cross, Worcester. George Barger, B.A., B.Sc., 50, Guilford Street, W.C. Charles Drake Bibby, 69, Queens Road, Twickenham. H. J.W. Brennand, B.A.,M.B., Ch.M., 203, Macquarie Street, Sydney, John Christopher Mann, 9, Lsmbert Street, Hull, 120 A ballot for the election of Fellows was held and the following mere subsequently declared duly elected : Henry Guest Adsliead. John George Collcutt Lock. M3lliam Lester St.John Alton. Arthur Ernest Pitt. Harford Montgomery Atkinson, C.Sc. Harold Russell Pitt. Xobert Gordon Bibby. George Gilbert Pond, Ph, D. George Neville Blackshaw, B.Sc. Robert James Porter. Harry Thornton Cslvert, R. Sc., Ph.D. Frederick Robertson. Ben Caudwell, B.A. Archibald Louis Robinson, B.A. Thomas Divine, 11.B., C. M. Fitzroy Owen Jonathan Roose. Arthur William East\yood, B. A. Ernest William Sawdon, B.Sc. John Percy Edgerton. George Siddle. Alan Fletclicr. Montague White Stevens. Henry Gough. Henry Edward Stevenson. George Howsam. Giles Hadtlen Welsford. Alfred Owen Jones. James Bates Wilkiuson, M. D., C.M. James Stewart Kerr. Williatn Francis John Wood, B.Sc. William Kirkby. Edward Chancey Worclen. Of the following papers, those marked * were read :-"59.Lt Thevelocity and mechanism of the reaction between potassium ferricganide and potassium iodide in neutral aqueous solution." By F. G. Donnan and R. Le Rossignol. When potassinm iodide and ferricganide react in neutral aqueous solution, free iodine and potassium ferrocynnide are formed, a definite state of equilibrium being attained. If the free iodine is removed as fast as it is formed by means of sodium thiosulphate solution, the velocity of the direct reaction can be investigated by a method similar to that employed by Harcourt and Esson in their fundamental investigation on the speed of chemical reactions. It was found that the re:tction proceeded according to the equation : -dc/dt =kc12c23, where c1 =concentration of ferricyanogen ions, and c2 =concentration of iodine ions.The simplest interpretation of this equation is that the primary reaction involves two ferricyanogen ions and three iodine ions according ---_----to the equation: 2Fe(CN), + 37 = 2Fe(CN)6 + Is. The exponents 2 and 3 of the velocity-equation were determined by separate variations of the ferricyanide and iodide concentrations. The foregoing account of the mechanism of the reaction does not, however, explain all the experimental results, inasmuch as it gives no explanation of the peculiar fact that although the reaction appears to be bimolecular with respect to the ferricyanogen ions (the concentratioll of theiodineions remainingconstant), nevertheless, the velocity-coeEcient varied with the initial concentration of the potassium ferricyanide. A theory which appears to be capable of giving a quantitative interpretation of all the observed results may be briefly summarised as follows : 1.The actual reaction is assumod to occur between free ferric ions +++ -+t--and iodine ions according to the equation, 2Fe + 31 = 2Fe + Is. 2. The ferric ions in question are assumed to result from an extremely small dissociation of the ferricyanogen ions into ferric and cyanogen ions. 3. The degrees of dissociation of the ferricyanogen and ferrocyanogen ions are assumed to be the mme, or practically the same, in solutions containing the same number of equivalents. DISCUSSION. RAMSAYSir WILLIAM said that Mr.Le Rossignol’s reaction was the first quinquemolecular reaction which, so far as he knew, had been investigated. It might appear almost incredible that free iron ions should exist in a solution OF potassium ferricyanide, but it must be remembered that their concentration was so low that the most delicate tests for iron, namely, the ferrocyanide and ferricyanide reactions, failed to detect them. Ah. Le Rossignol had made an experiment in which he had electrolysed some potassium ferrocyanido, and he had obtained, after a long time, a deposition of metallic iron on the cathode; this, of course, might be due to a secondaryreaction, but, SO far as it went, it was in corroboration of the theory. *60. (‘A microscopic method of determining molecular weights.A preliminary note.” By G. Barger. When two solutions of equal vapour tensions, produced by dissolv-ing two substances in the same solvent, are left in a closed chamber, their volumes will not alter after the chamber has become saturated with the vapour of the solvent. If, however, the vapour tensions are unequal, the solvent will distil from the solution with the greater vapour tension into that with the less. As the result of a suggestion by Prof. L. Errera, of the botanical laboratory of Brussels University, to the effect that this principle might be used for determining molecular weights, the author has elaborated a met,hod, which apparently differs in certain essential feattires from those hitherto published, and is briefly as follows : A 11 22 standard solution of the substance, the molecular weight of which is to be determined, is compared with a number of standard solutions of a substance of known molecular weight.Small quantities of the two solutions which are being compared are introduced into a capillary tube, where they form bi-concave, discoid drops, care being taken to use the solutions alternately, so that each drop of one solution is enclosed between two drops of the other. The capillary tube is then sealed at both ends, and the length of each drop is measured under the low power of a microscope with the aid of an eye-piece micrometer. After a few hours, or a day, the measure- ment is repeated, when, if the vapour tensions of the two solutions are unequal, the drops of one series are found to have increased in size, whilst the others have correspondingly diminished.By using standard solutions of various strengths, an approximate value for the molecular weight is obtained, the limit of accuracy attained at present being about 10 per cent. The method will undoubtedly be useful in deciding between multiples of an empirical formula in those cases where ebullioscopic methods are not available. *61. ‘‘Note ofi the spectrum of pilocarpine nitrate.” By W. N. Hartley. In the current number of the Transuctions, p. 452, there is a representation of the absorption curve of pilocarpine nitrate as deter- mined by Professor Dobbie. In the author’s opinion, the curve is that characteristic of nitric acid, and is only indirectly associated with pilocarpine, certainly not belonging, or peculiar to, this alkaloid.On comparing the diagram with the curve common to nitric acid and potassium nitrate (Trans., 1902, 81,558), the similarity is easily recognised. Although there are slight differences of detail in the absorption band, these are due to the recorded measurements not being made at exactly the same points or with solutions of the same concentration, and also in part. to a slight modification of the nitric acid curve caused by the pilocarpine molecule. Pilocarpine, if examined by itselE or as a salt of any diactinic acid such as hydrochloric, acetic, or sulphuric acid, will be found to exhibit no absorption band.This may be predicted both from the fact that pilocarpine nitrate is highly diactinic, and that stronger solutions than are usually em-ployed were necessary in order to obtain clear indications of the absorption band, and also from the composition and structure of the 123 molecule, the evidence for which is adduced by Dr. Jowett. It is probable that pilocarpine and isopilocarpine are not structurally different, although the manner in which they were examined does not justify the conclusion that their absorption curves are identical. It is not safe to draw inferences from solutions of nitrates of the alkaloids, particularly when the bases themselves exert but little absorption. In such cases, a more searching examination might disclose differences between the alkaloids, As the communication neither refers to the existence of the absorption band of nitric acid nor contains evi-dence of the absorption caused by pilocarpine and of isopilocarpine alone or in combination with a highly diactinic acid, it might be sup- posed from a study of the paper that pilocarpine was characterised by an absorption band, but this is certainly not the cdse.It is evident that, as with caffeine, digitaline, and similar alk’aloids (Phil. Trans., 1885, 176,471), the structure of pilocarpine does not confer on the base any peculiar absorptive power or selective absorption. DISCUSSION. Dr. DOBBIEsaid that the purpose of Professor Hartley’s note was not to call in question the validity of the conclusion that pilocarpine and isopilocarpine are probably isomerides, which had been based on the comparison of their nitrates, but to point out that no information as to the chemical structure of these bases could be derived from the fact that concentrated solutions of their nitrates showed a well-marked absorption band.Such bands are usually, in the case of organic compounds, associated with the possession of a benzenoid, pyridine, or similar nucleus, but, inasmuch as nitric acid itself in concentrated solution gives a well-marked absorption band, the presence of a band in the nitrates exam- ined afforded no evidence of the presence of such a nucleus in the alkaloids. The band of pilocarpine, and of isopilocarpino nitrate, occupies the same position, and is very similar to, mikhout being actually identical with, the band of nitric acid.Professor Hartley regards it as the band of nitric acid modified by the presence of the alkaIoid. It is this modification of the band which is of importance in relation to the comparison bet ween pilocarpine and isopilocarpine, instituted in Dr. Jowett’s paper, Since the modification is exactly the same in both cases, the conclusion that; pilocarpine and isopilocarpine must have the same chemical structure remains unaffected. In this case, it was necessary to use concentrated solutions of the nitrates for the investigation, because it was found impossible to obtain satisfactory solutions of the free bases. In the case of alkaloids of high molecular weight, such a6 loerberine, 124 the absorption spectra of dilute solutions of the nitrate are practically the same as those of the chloride, and wholly different from the spectra of nitric acid.Professor Hartley's caution as to the employment of nitrates in the investigation of chemical structure by the spectroscopic method applies, therefore, more particularly to those highly diactinic substances, which, like pilocarpine, have comparatively low molecnlar weights, 62. Isomeric change of dipropionanilide into propionyl-p-amino- propiophenone." By F. D. Chattaway. Under the influence of various reagents, dipropionanilide, like diacetanilide and dibenzsnilide, undergoes transformation into pro- pionyl-p-aminopropiophenone : NH*CO*C,H, /\ Although the o-derivative is piobably also formed in small amount, only thep-derivative can be isolated in quantity.As a catalytic agent, zinc chloride gives the best yield, but hydrogen chloride is also applicable, the transformation being most readily effected by heating propionanilide dissolved in an equivalent amount of propionic anhydride with about one-third its weight of dry powdered zinc chloride for 12 to 16 hours at 140-150'. The product, after hydrolysis with alcoholic hydrogen chloride, is rendered alkaline and distilled in steam, the paminopropiophenone separating from the residual solution in reddish-yellow plates (yield =50 per cent.). The base, which is obtained colourless by crystallisation from alcohol or chloroform, separates in flattened rhombs (m.p. 142') ; its acetyl derivative forms colourless, hexagonal prisms (m. p. 175"). Kunckell (Ber., 1900, 33,2641) describes these compounds as crystttl-lising in yellow needles melting respectively at 140' and 161'. p-Aminoz~royio~~~enonesuZphate, (C,H,*CO*C,H4*NH,),,H2S04,a sparingly soluble salt, forms anhydrous, colourless plates which become red and decompose at 223' ; the plttinicldos-ide, (C,H,*CO C,H;NH,),,H,P tGI,, forms small, orange-coloured needles. p-Acetglchlorouminopyopiophenone,C,H,*CO*C,H,*NClAc, colourless plates, m. p. 15' ; p-cccel?/Zbi.onioccmiizo~~roi)io~~~~~~o~~,short, yellow prisms, rn . p. 115' ;p-l'roi~ionyln?riino2~~~~~io~~~e.ao~ie, (2, €If,.C0.C,€I &N lI.CO.C,II,, 125 slender, colourless prisms, m.p, 153' ; p-propion?/lchlol.oaminopl.o~~o-phenone, C,H,*CO.C,H,*NCI*CO*C,H,,colourless plates, m. p. 130"; p-propionylbromociminopopiophenone, pale yellow, elongated plates, m. p. 120' ; p-benxoylaminopropiopJLenone, C,H,*CO*C,H,*NH*CO*Ph, thin, colourless, elongated plates, m. p. 190" ; p-benzoylcbloroanzinopropio-phenone, C,H,*CO*C6H,*NCl*CO*Ph, colourless plates, m. p. 70" ; p-benxoylbromoaminopropiophenone,bright yellow, rbom bic plates, m. p. 111". When heated quickly, the nitrogen-halogen derivatives all undergo transformation at about 200-230" with much decomposition. 63. Li Note on the formation of di-and hexa-methylammonio-cadmium chlorides," By W.R.Lang. Dry methylamine and cadmium chloride roact at -1l0,but not at -SO", to form a white powder, corresponding with the formula CdCI,,GCH,*NH,. When heated to loo', .z stable substance is obtained having the composition CdC1,,2CH,*NH2, its decomposition is not complete at 300O. ADDITIONS TO THE LIBRARY. 11.By Purchase. Glnser, Christopher. The Compleat Chymist, or a New Treatise of Chymistry. Teaching by a short and easy method all its most necessary Preparations. Written in Pvench by Christopher Gk6ser, Apothecary in Ordinary to the French King, and the Duke of Orleuns. And from the fourth Edition, Revised and Augmented by the Author. Now faithfully Englished by a Fellow of the Royal Society. Illustrated with Copper Plittes. London 1677.111.Pamphlets. Bull, Irving C. On the determination OE lead in ores. (From the Xclbool of Mines Quarterly, 1902, 23,p. 348.) Cutolo, Alessnndro. Sulla ricerca delle sostanze coloran ti artificiali negli alimenti in decomposizione. (From the Bull. SOC. Nut. ATupoli215, 1901.) -Brodo di sangue (nuovo terreno di culturst). (From the Bull. $oc. Nut. NapoEi, 16,1902.) 126, Doane, Charles F., nnd Price, T. M. Tho infliience of preservatives upon the food value of milk. (Bull. Xo. SG, Mar&md Ags*ic. Exper. Station, 1902.) Thomsen, Julius, Fremgangsmssde, ved hvilken det hidtil hypo-tetiske stof Enkelt-svovlkulstof (CS.) med lethed ka.n dannes. 1902. Van SIyke, L. L., and Hart,, E. B. A study of some of the salts formed by casein and paracasein with acids; their relation9 to American cheddar cheese (being BuZI.30.214, New York Agric. Ezpev. Station, 1902). Guthrie, Frederick Bickell. Analysis of Prickly Pear. 1900. Colorado. The University of Colorado Studios. Vol. I. No 2. 1902. Stieglitz, Julius. On the ‘6 Beckrnann rearrangement.” (University of Chicago Decennial Publications.) Chicago 1903. RESEARCH FUND. A meeting of the Research Fund Committee will be held in June. Applications for grants, to be made on forms which can be obtained from the Assistant Secretary, must be received on or before June Sth. At the next meeting, on Thursday,May 7th, at 8 p.m., the following papers mill be communicated : ‘(P-Bromonitrocamphor and /3-bromocamphoryloxime. Influence of impurities in conditioning dynamic isomerism.” By T.M.Lowry. ‘‘The spontaneous decomposition of nitrocamphor.” By T. M. Lowry. ‘iThe active constituents of Butea Frondom.” By E. G. Hill. 8.LLAY AND SONS, LID., BREAJ)ST. HILL, E.c.?AND RUNGAY, SUFFOLK.
ISSN:0369-8718
DOI:10.1039/PL9031900119
出版商:RSC
年代:1903
数据来源: RSC
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