摘要:

THE VJSCOSlTY OF CERTAIN AMIDES. 1935CCV.-The Viscosity of Certain Amides.By ALBERT ERNEST DUNSTAN and ALBERT GEORGE MUSSELL.THE peculiarly constitutive nature of viscosity confers on it con-siderable value in discriminating between two possible types ofstructure. The amides may react as though they possessed theOH formulae R*CO-NH, or R*CqNH (Tafel and Enoch, Bet-., 1890,23, 1550; Lander, Trans., 1903, 83, 418), although by comparisonwith a genuinely hydroxyiminic compound, such as glycollimino-hydrin, Hantzsch and Voegelen (Ber., 1901, 34, 3142) regardR-CO-NH, as the correct formulation for the amides. From aphysical point of view the amides are undoubtedly amociate1936 DUNSTAN AND MUSSELL :(Auwers, Zeitsch. physikal. Chem., 1893, 12, 689; 1894, 15, 33;1897, 23, 449; 1899, 30, 521), and the fact that they form additivecompounds (Titherley, Trans., 1901, 79, 413) indicates that thegroup *CO*NH, possesses considerable residual affinity.I n furthersupport of the usual amidic structure may be cited the work ofHantzsch and Dollfus (Ber., 1902,35,226) and Schmidt (Ber., 1903,36, 2459). Fawsitt (Proc. Roy. Soc, Edin.., 1904, 25, 1, 51) foundthat the fatty amides in aqueous solution were non-electrolytic, andgave normal depression of the freezing point. The same chemist(Electrochemist and Metallurgist, 1904, 3, 664) determined theviscosities of a few amides in aqueous solution, and showed thatthe viscosity increased with increasing molecular weight.Meldrum and Turner (Trans., 1908, 93, 876), in an ebullioscopicexamination of a considerable number of amides, found that 90 percent.of those used were associated in benzene, 80 per cent. inether, 80 per cent. in chloroform, 10 per cent. in acetone, 45 percent. in water, and probably 20 per cent, in ethyl alcohol. Theyconnected these results with the dielectric constants of the solvents,and considered that the carbonyl group or the nitrogen atom wasthe centre of association.Turner and Merry (Proc., 1910, 26, lB), using Ramsay andShields’ method, state that all the amides investigated by them areassociated.The object of the present work was t o investigate the viscosity ofthe amides with the view of detecting any hydroxylic nature, forsuch structure has been found to affect very materially this propertyO H in aqueous solution.Again, if the amides possessed the -C‘qNHgroup, then, in pyridine solution, salt formation would probablyoccur, with enhanced viscosity. Further, the viscosity of the amidesin the free condition had not been pr$viously investigated, and itwas of interest to determine the equivalent viscosity as being likelyto throw light on their relative degrees of association.EXPERIMENTAL.The viscosity of a large number of amides, both fatty andaromatic, has been determined f o r the free substances and foraqueous and pyridine solutions. The materials used were a,s follows :Carhami&.-Kahlbaum’s purest, 111. p. 132O.Formamide.-Kahlbaum’s, redistilled under diminished pressure.2.916 grams, boiled with alcoholic potash (70 C.C.of 1*155N),used, after boiling, 16-25 C.C. of N-sulphuric acid, whenceMCO-NH, = 99.7 per cent. Boiled with decomposition at 204O1758 mm. ( 2 0 8 O corr.); b. p. 141°/65 mm., 136O/50 mm. BruhTHE VISCOSITY OF CERTAIN AMIDES. 1937(Zeitsck. physikal. Chem., 1894, 16, 214) gives b. p. 111-112°/14 mm.A cetamide.-Kahlbaum's, m. p. 8 2 O , redistilled b. p. 215*5O/749 mm.Propionamide.-Kahlbaum's, m. p. 80-81O.n-Butyramide.-Kahlbaum's, m. p. 116'.Thioca~b anzide.-Schuchar dt's, m. p. 149O, crystallised fromd cetaniZide.-Prepared from aniline, recrystallised several timesBenzarnide.-Kahlbaum's, recrystallised from hot water, m. p.BenzaniZide.-Schuchardt's, m. p. 160°, crystallised from alcohol.T~~~ocarbaniZide.-Schuchsrdt's, recrystallised twice from alcohol,m.p. 153O.Metlz ylacetaniZide.-Prepared from methylaniline, recrystallisedfrom alcohol, m. p. lolo, b. p. 2 3 7 O .DiphenyZca;l.bam,ide (carbanilide).-Prepared from ketobenz-oxazole and aniline, crystallised from much alcohol, m. p. 234' (insealed tube).water.from water, m. p. 1 1 2 O , b. p. 283O.128O.Uretlmne.-Kahlbaunl's, m. p. 51°, b. p. 179O/749 mm.Cyanuric d cid.-Kahlbaum's, recrystallised from hot water.FormaniZide.-Schuchardt's, recrystallised from hot aqueousPhthaZuniZ.-Schuchardt's, m. p. 205O.Plttha.limide.-Schuchardt's, recrystallised from alcohol, m. p.2 30°.Sol ZI en t 8.-Conductivi t y water, p yridine p art>ly from Kahlb aum,dried over potassium hydroxide, b. p. 114--116O/742 mm.(corr.),partly from crude coal-tar pyridine fractionated with a long rod-and-disk column, b. p. 116O.Magnitude of Experimental Er-ror.-Densities were taken inSprengel pyknometers of 2 C.C. capacity. Two determinations weremade, and these usually agreed within a milligram. The densityerror is not greater than 0.05 per cent. Times of flow were takenuntil about five concordant results were obtained agreeing withinone second; as an example the following may be quoted :alcohol, m. p. 46--47O, b. p. 271O.Butyramide, 16.88 per cent. in water.Greatest mean error=O*17 sec.3' 27'4''; 3' 27'4'' ; 3' 27.6'' ; 3' 27'5" ; 3' 27.7" ; 3' 27.6''. Average=$ 27*53^.The viscosity error may be taken as k0.1 per cent.To obtain the equivalent viscosities, two or more determinationsA curve was then were made at different (low) concentrations1938 DUNYTAN AND MUSSELL :drawn practically linear near the origin.By arranging theequivalent concentration so low its mol. wt.j20, it was possible tointerpolate from this linear portion, and so obtain a more correctvalue than could be observed directly.The viscosities at high temperatures are not so accurate, since it isvery difficult t o secure effective thermo-regulation. An examplewill illustrate the method :Temperature Temperaturea t start. at end. Time of flow.104-8" 105.0" 5.28105'0 103.8 5-31104.8 104-6 5.27105'0 105.7 5.27L 2 v Avernge temperature 104 '8The viscosity error is probably k0.5 per cent.The following tables show the resu1t.s obtained; the figures in thefirst column representing percentages of the substance in the solvent.Average 5 -282TABLE I.Amides in Aqueous Solution at 25O.(1).Carbamide-Density.1 *02 1 -0008-13 1.01811.89 1 '02915.47 1'03323.12 1.05933'28 1.08738.13 1.10246.18 1.125(2). Formanzide-l * i O 0.999940'22 1-05452.2 1-06975.42 1.11579.15 1.118100.0 1.132(3). Acetamide-0.78 0.99775-82 1 -00117-69 1.00825.95 1,01537'21 1,0226926 1 -038Viscosity.0*008950.009390.009690 *010350.010880.01 2520 '013480 015610 -009210'011820.012830'021010 '0 22 T 5 ;:;;;;: }0.008900.009910.01 2320'014580.018750'04442(4). Propionavtide-Density.1.245 0'99745.65 0 998411 071 1 .on022-18 1.00641 -48 1.01170.65 1-011( 5 ) .mBt6tyramide-1 *02 0.99728-11 0'997416.88 0.998417'92 0.9987(6). Formic acid-3 05 1 0 0 427-38 1.06073-55 1.161100 0 1 '209Viscosity.0.009190*010250.01 1880.015360'030300.059800*009060'011220 *0145 80 '01 5 110*009070*010410 -0 1 3790.01 5 80* From two specimens from KahlbaumTHE VISCOSITY OF CERTAIN AMIDES.Amides in Pyridine Solution at 25O.Thiocarbamide-Density.5 -52 0.994912.57 1'019Aeetamide-3.87 0.979416'27 0.9959Benamide-5'16 0.983912-46 0,9971Benaccnil ide -5'40 0-98299.02 0'990212-75 0'9964Thwcarbanilide-7-40 0.991914.51 1 *005Met h y hcetamide-6.59 0.978611.2 0.981916-44 0.9844Carbanilide-5.69 0.98417-19 0.9862Urethane-9-09 0'983214'96 0 9899Viscosity.0.012510*020190.009870-013810*010550 *013 3 10 '0102'10 -01 1210 '012520*011590*014160.009670'020220 *O 108 20*010450.010790.010700 .o 1202Propioxamidc -Density.7'92 0.976923.75 0.981713'66 o m 9Cyanuric acid-3.20 0'9874Forwunilide-10.32 0-990319'14 1'004Phtha Zad-3-55 0.9821Phtha Zinaide-5.05 0987611.93 1.006Formanzide-7.77 0-987111'10 0993517.12 1*G0075.65 0.98148 $1 0.9826Acetamide-Carhamide-0'91 0.9802PyridilLe *-100-0 0.97461939Viscosity.0 *0104 70.012080*016150*010380.010890 '01 3 350.0096060.0098780.01 1820'010640.01 1600.013650.010050 010880-009390.00884* Hartley, Thomas, and Applebey (Trans., 1908, 93, 544) give 0.00885.The Viscosity of the Amides at High Temperatures.To obtain comparable information as to the relative state ofassociation of the amides, it was necessary to work at somewhatelevated temperatures, seeing that propionamide melts at 81° andacetamide at 82O.A description of the apparatus used may be ofinterest.A large beaker filled with cylinder oil of high flash-point wassupported on wire gauze and jacketed with asbestos paper, throughwhich two opposite longitudinal slits were cut for observations oftmhe viscometer. Through the metal lid passed a thermometergraduated in fifths of a degree, a stirrer connected with a Henricimotor, and the viscometer. The latter was designed with theview of increased accuracy in filling.The usual method (Ostwald,Physico-Chemicd Measurements, 1894, 163) is to run in a know1940 DUNSTAN AND MUSSELL :volume of liquid from a pipette. This is obviously impossible whenworking with a substance which is solid at the ordinary tem-perature, unless the pipette can be kept at a sufficiently high tem-perature, so that the instrument shown in Fig. 1 was used. It isof the Ostwald type, and merely possesses two etched lines at theUFIG. 1.same level on the same limb. The viscometeris cleaned and dried, and the compound underobservation is distilled into it. Where distillationis impossible, the melted substance must be filteredin. Unless filtration or distillation is resorted to,it is practically impossible to secure freedomfrom particlm of dust, which will inevitablychoke the capillary. This is the most fertilesource of error in viscometry.The instrumentfilled just above the marks is placed in the oil-bath, and levelled by means of a gravity bobhung from the supporting clamp. After remain-ing for ten minutes to attain the bath tem-perature (a thin flame obtained from a Bunsenburner after unscrewing the chimney, and con-trolled by a long lever on the tap, gives excellenttemperature regulation), the liquid is adjusted tothe marks by a capillary pipette, and times offlow are taken and averaged. Absolute densitieswere measured in a 10 C.C. bottle-shaped pykno-meter filled with fused compound. A correctionwas applied for the known coefficient of expansionof the glass, the volume being determined at2 5 O and 4 5 O by the water content.following way :The viscometer wits calibrated with ethylene dibromide in theLog viscorneter constant = log r] - log time - log density.At 105O,Time of flow at 105O= '77.4 secs., and at 120°= '71.9 secs.Density at 105" = 2.009, and at 120°= 1.979.whence log K,, = 5.6138, and log K,, = 5.5965.Hence the viscosity of a compound at 120° or 1 0 5 O is obtainedfrom the equation q = K x time x density.The ethylene dibromide used for this purpose boiled at 129'5O/749 mm.for ethylene dibromide = 0.00639 (Thorpe and Rodger).A t 120°, q 9 9 ,, =0.00562 ,, 9 TEE VISCOSlTY OF CERTAIN AMIDES. 1941TABLE 11.Amides at High Temperatures.105" :Formamide ............Acetamide ............Propionamide ......Urethane ............120" :Formamide ............Acetaiiiide ............Propionamide ......Urethane ............Formzlnilide .........Acetanilide............Methylacetanilide ...v.0.007680'01320.01270 -00 9 160.006590*01060.01030'007 150.01650'02220'00818d.1.0610.9800.9331 *0051.0500.9670-9250.9911.0761 '0310.977Mol. wt. q x 106/M.V.45 18159 21973 16289 103.545 15459 17473 13689 77'8121 147135 170149 53 -6Discussion of Results.The Amides in Aqueous Solution.Formamide, acetamide, propionamide, n-butyramide, and carb-amide were examined in aqueous solution. I n Fig. 2 are plottedthe viscosity-concentration curves of the above amides, togetherwith those of formic acid and methyl alcohol for comparison.In connexion with forma.mide, Walden (Zeitsch.Electrochem.,1908, 14, 718) found a high value for the latent heat of fusion(50.4, acetamide being 69.4). Noreover the expression for l ' eformamide is 8.31, and for acetamide 11.51, giving the coefficientsof association 1-62 formamide, and 1-17 acetamide.The rapid increase of viscosity with increasing amide concentrationis remarkable, and indicate very considerable aisociation on thepart of these compounds. Comparing formamide and formic acid,which yield curves of similar type up to a concentration of 30 percent., it is evident that beyond this limit the formamide curve risessteeply until the relatively high viscosity 0.0326 is reached for thepure substance.x 106 has a seriesconstancy; for example, for alkyl chlorides it is 37.4, and forketones 43-3 (Dunstan and Thole, J .Chim. Phys., 1909, 7, 204),whilst for associated compounds values in great excess of these areNow it has been shown that the quantity M. ??q x 106obtained, For formamide, - - - 682, and for formic acid this M. V.expression = 415. There is thu? little doubt that formamide in thefree state is extremely associated, and although these numbers d1942 DUNSTAN AND MUSSELL :not give an exact value for the degree of association, yet it ispossible, qualitatively, to obtain a very fair idea of the relativeextents of the molecular complexity. By measuring off the curves,the values of the viscosity coefficients at equiinolecular concen-trations, the following numbers are obtained :Mol.wt. Amide.87 Rutyramide ..................59 Acetamide., ..................60 Carbarnide ....................45 Formamide ..................46 Foriiiic acid ..................32 Methyl alcohol ...............73 Propionamide ...............FIG. 2.0*04000.0320 55-2**9) 22 0.02407hi,0*01600~00800Equir. d e n t viscositya t mol. wt./8 per cent.12211010294909299The above equivalent viscosities in aqueous solution illustrate thedissociating action of the solvent. Formamids is almost completelybroken down, since its equivalent viscosity is nearly identical withthat of formic acid, which does not exist associated with water inaqueous solution.Methyl alcohol, on the other hand, is mostprobably associated with the solvent. There is a steady increasTHE VISCOSITY OF CERTAIN AMIDES. 1943in viscosity as the molecular weights of the amides become greater.According to Meldrum and Turner (Zoc. c i t . ) , the amides areassociated in aqueous solution with the possible exceptxion ofcarbamide (formamide was not examined by them).The position of carbamide is interesting, seeing that the curvelies almost exactly midway between those for acetamide andformamide. Although of nearly identical molecular weight, theequivalent viscosity is considerably lower than that of acetamide.Here, however, another consideration should be advanced.Viscosity is not entirely a matter of molecular mass or molecularvolume.What may be termed the molecular shape or symmetrycannot be ignored, and in accordance with this view it is foundthat the viscosity of iso-compounds differs from that of the normalisomerides. It may happen that carbamide is a more symmetricalcompound than acetamide, in which case, although the degree ofassociation might be the same, the molecular viscosity would be less.The Amides in Py?.idine Solution.The choice of pyridine was made in the expectation that if anytendency existed towards the structure *CGNH on the part of theamides, it would be developed by the well-known basic propertiesof this solvent. With the possible exceptions of thiocarbamide,cyanuric acid, and thiocarbanilide, this hope was not realised, butat the same time it will be evident from the curve that anapproximate separation of the amides in the order of theirmolecular complexity is achieved.Pyridine is a dissociating solvent(von Laszczynski and von Gorski, Zeitsch. EZektroc7tem., 1897, 4,299), and, like water, tends to break up the aggregates presented toit. It is particularly noteworthy that the amide the molecularviscosity of which was smallest in the fused state, methylacetanilide,affords the curve with the least upward tendency, that is, the leasteffect on the viscosity of the solvent. For the sake of comparison,viscosities of the solutions have been measured at equivalent con-centrations, mol. wt./20 per cent.OHThe order then becomes:Mol.wt.4559149897312160123At mol. wt./20Amide. per cent.Formamide ......... 0 '0093Acetamide ......... 0 '0095Methylacetanilide . 0.0097Urethane ............ 0.0097Propionamide ...... 0 -0097Forrrianilide ......... 0 -0098Carbamide ......... 0'0102Ph thalimide ......... 0 -0 102Mol. wt.12113576.212223197129228At mol. wt.120Amide. per cent.Benzamide ......... 0 -0 108Acetanilide ......... 0 -0108Thiocarbamide.. .... 0*0109Carbanilide ......... 0 -01 10Phthalanil ......... 0 *0114Benzanilide ......... 0-0116Cyanuric acid ...... 0'0120Thiocarbanilicle ... 0.0131944 POWER ANb ROGERSON!The value for carbamide is not of the same order of accuracy asthe other amides, seeing that a concentration of 1 per cent. was thehighest obtained. If it be granted that the amides in certaininstances do react as acids, then the high molecular viscosities ofthiocarbanilide and benzanilide would be explained, and thisexplanation is at least a possible one. But at the same time thenon-acidic nature of the fatty amides is emphasised. The valuesin pyridine solution are complicated therefore by two causes: (1)the dissociation more or less complete suffered by the dissolvedsubstance; (2) the effect of m y acidic nature of the solute. Whenthe equivalent viscosities in pyridine are compared with those inaqueous solution, it is again noticed that formamide has the lowestvalue; this, of course, may be in each case due to the fact thatit is the most easily dissociated, but it must be emphasised oncemore that the question of molecular symmetry cannot be ignoredin drawing comparisons based on viscosity determinations. Weintend extending this research to the investigation of the generalquestion of solutions in the amides, and particularly to the questionof relative viscosities at corresponding temperatures,In conclusion, we desire to express our gratitude to Mr. W. E. S.Turner for many useful suggestions and criticism, and to theResearch Fund of the Chemical Society for a grant in aid of thework.PHYSICAL CHEMICAL LABORATORY,E A S T HAM TECHNICAL COLLI4CGR

ISSN:0368-1645    

DOI:10.1039/CT9109701935

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

1944 POWER ANb ROGERSON!CCVL-The Constituents of Leptandra.By FREDERICK BELDING POWER and HAROLD ROGERSON.UNDER the title of (( lept,andra,” the Pharmacopaia of the UnitedStates recognises the dried rhizome and roots of Veronica virginica,Linn6 (Leptandra virginica, Nuttall), a plant which is indigenousto the greater part of North America. The above-mentionedunderground portion of the plant is used medicinally, and the cruderesinous material obtained therefrom is one of the products to whichthe name “ leptandrin ” has been assigned.The first chemical examination of (‘ leptandra ” appears to havebeen that recorded by E. S. Wayne (Proc. Amer. Pharm. Assoc.,1856, p. 34), who stated that, besides essential oil, bitter extractive,tannin, gum, and resin, it contains a crystalline, bitter substanceTHE CONSTITIJENTS OF LEPTANDRA. 1945which separated from the ethereal solution in needles.This sub-stance, although not further characterised, was considered to repre-sent the active principle of the drug, and for it the name “lep-tziidrin ” has since been proposed. The same investigator (Amer.J . Plzarrn., 1859, 31, 557) also observed the presence of “ asaccharine principle having the properties of mannite.” It wassubsequently indicated by F. F. Mayer (Amer. J . Pharrn., 1863,35, 298), and more recently by J. U. Lloyd (Proc. Amer. Pharm.Assoc., 1880, 28, 421), that the bitter principle of the drug is aglucoside, although no definite substance of this class had actuallybeen isolated. Steinmann (Amel.. J .Pizurm., 1887, 59, 229) statesthat he obtained the bitter principle in crystals of a pale lemon-yellow colour, but they yielded no dextrose when boiled with dilutesulphuric acid, and their solution gave no precipitate with theusual alkaloid reagents.It will be apparent from the brief review of the literature givenabove that, with the exception of the recorded presence of mannitol,nothing of a, very definite nature has up to the present been knownrespecting the constituents of ‘( leptandra.” It was thereforedeemed of interest t o subject it to a complete examination, andthe results are embodied in the present communication.EXPERIMENTAL.The material employed for this investigation consisted of a goodquality of commercial “leptandra,” which conformed in its charactersto the description given of the latter in the United StatesPliarmacopa4a.A small portion (10 grams) of the material was first tested for analkaloid, but the reactions were so slight as to indicate the presenceof not more than traces of such a substance.Twenty grams of the ground material were successively extractedin a Soxhlet apparatus with various solvents, when the followingamounts of extract, dried at looo, were obtained:Petroleum (b.p. 35-50“) extracted 0.11 gram -T 0.65 per cent,Ether ,, 0.56 ,, = 2’80 ,,Chloroform ,) 1-00 ,, = 5-00 ,,Ethyl acetate ,, 0 65 ,) = 3.25 ),Alcohol ,, 2.95 ,, =14.75 ,, - -Total 5 -27 grams = 26 *35 per cent.For the purpose of a complete examination, a quantity (55.56kilograms) of the ground material was extracted by continuouspercolation with hot alcohol. After the removal of the greaterportion of the alcohol, a viscid, dark-coloured extract was obtained,amounting to 19.79 kilograms.VOL.XCVII. 6 1046 POWER AND ROGEHSON :Distillation of the Bxtract with Steam. Separation of anE'ssentid Oil.A quantity (2 kilograms) of the above-mentioned extract wasmixed with water, and steam passed through the mixture forseveral hours. The distillate, which amounted to about 6 litres,contained some oily drops floating on the surface. It was thoroughlyextracted with ether, the ethereal liquid being dried and the solventremoved, when 0.9 gram of an essential oil was obtained. Theyield of the latter was thus equivalent to 0.16 per cent. of theweight of the drug.This essential oil, when distilled underdiminished pressure, passed over between 120° and 160°/25 mm.It was a dark brown, mobile liquid, possessing a strong, persistentodour, and gave no coloration with ferric chloride.Non-volutile Constituents of the Extract.After the distillation of the extract with steam, as abovedescribed, there remained in the distillation flask a dark-coloured,aqueous liquid (A), and a quantity of a dark brown resin (B).These products, when cold, were separated by filtration, and theresin repeatedly washed with hot water until nothing further wasremoved, the washings being added to the aqueous liquid.Examination of the Aqueous Liquid (A).Isolation of 3 : 4-Bimethoxycinnamic Acid,C,H,(OMe),*CH :CH*CO,H.The aqueous liquid was repeatedly extracted with ether, and thecombined ethereal extracts evaporated to a small volume.Oncooling, a quantity (5.0 grams) of a crystalline substance separated.This was removed by filtration, dried, and recrystallised from water,when it separated in yellow needles, melting at about 170°, butafter repeated crystallisation from absolute alcohol it was obtainedin large, colourless needles, melting at 180-181O. (Found, C = 63.4 ;H = 5-9 ; OMe= 29.2. Cdc., C = 63-5 ; H = 5.8 ; OMe = 29.8 percent.)The substance was found to be an acid, and is seen to agree in itscharacters and composition with 3 : 4-dimethoxycinnamic acid,C,H,(OMe),*CH:CH*C"02H. When mixed with a portion of thelatter, as obtained by the methylation of ferulic acid (Trans., 1907,91, 8931, the melting point w a unchanged. Furtiher confirmationof the identity of the acid was obtained by t b preparation of itsmethyl ester, which separated from absolute alcohol in smallprisms, melting at 64O.So far as known t o us, this is the firsTHE CONSTITUENTS OF LEPTANDRI. 1947instance in which 3 : 4-dimethoxycinnamic acid has been observedto occur in nature.The ethereal liquid from which the above-described acid had beenseparated was diluted somewhat, and then shaken with successiveportions of aqueous ammonium carbonate. On acidifying thealkaline liquids, a solid substance was p,recipitated, which waslikewise found to consist. of 3 : 4-dimethoxycinnamic acid.Thetotal amount of this acid obtained from 2 kilograms of the originalalcoholic extract was 12.0 grams, and was thus equivalent to about0.2 per cent. of the weight of the drug.The ethereal liquid was subsequently shaken with a solution ofsodium carbonate, which, however, removed nothing. It was thentreated with a 10 per cent. solution of sodium hydroxide, when aquantity of resinous material was removed, but from which nothingdefinite could be isolated. On finally evaporating the ether, onlya small amount of a yellow, amorphous product: was obtained.The original aqueous liquid (A), which had been extracted withether as above described, was thoroughly shaken with successiveportions of amyl alcohol. These liquids were then united, washedrepeatedly with water, and concentrated under diminished pressuret o a small volume, when, on cooling, a considerable quantity of alight brown, amorphous product separated.After removing theamyl alcohol as completely as possible, the entire amount of thisproduct was dissolved in alcohol, and the solution poured into alarge volume of water. The precipitate thus produced was collected,washed, and dried, when it could be reduced to a brown powder,but all attempts to obtain it in a crystalline state were unsuccessful,It amounted to 90 grams, or 1.6 per cent. of t.he weight of drugemployed.The abovedescribed product possessed an intensely bitter andnauseous taste. It was readily soluble in alcohol, but very sparinglyso in water, even on boiling.Although the very dilute aqueoussolution frothed strongly on agitat,ion, the substance appeared topossess otherwise none of the characters of the saponins, and it wasnot sternutatory.In order. to obtain some further information respecting thecharacter of the above-described product, a quantity (10 grams) ofit was heated with 1000 C.C. of 2 per cent. aqueous sulphuric acidfor about four hours, when, on cooling, a hard, black, resinous massseparated. The liquid was then distilled in a current of steam,the distillate extracted with ether, and the ethereal liquid shakenwith a solution of sodium carbonate. On acidifying the alkalineliquid, again extracting with ether, and removing the solvent, a6 M 1948 POWER AND ROGERSON:small amount of an acid was obtained, which, on cryst,allising fromwater, separated in leaflets, melting at 131-133O.This acidyielded benzaIdehyde on oxidation, and was identified as cinnamicacid. The ethereal liquid which had been extracted with alkali wasfinally evaporated, but it yielded only a trace of a deep yellow oil.The aqueous, acid liquid remaining after the distillation withsteam, as above described, was separated from the hard, black,resinous mass, which weighed 5.5 grams, and shaken with ether, theethereal liquid being subsequently extracted with a solution ofammonium carbonate. On acidifying the alkaline liquid, againextracting with ether, and removing the solvent, about 0.3 gramof a crystalline product was obtained, which was found to consistof a mixture of acids.The ethereal liquid which had beenextracted with alkali was finally evaporated, but it yielded only asmall amount of a yellow oil, which gave a green coloration withferric chloride.After extracting the above-mentioned aqueous, acid liquid withether, it was treated with barium hydroxide for the removal ofthe sulphuric acid. The filtered liquid readily reduced Fehling’ssolution, but no crystalline osazone could be prepared from it.From the above results it was evident that the bitter, amorphousproduct, which had been obtained by extracting the originalaqueous liquid with amyl alcohol, was of a complex nature, andthat not more than a small proportion of it could have beenglucosidic. It was, moreover, apparent that the acids which ityielded by treatment with dilute sulphuric acid were present in theform of esters, inasmuch as on heating the product with aqueoussodium hydroxide a similar mixture of acids was obtained, and inbetter yield. This mixture of acids was found on examination toconsist chiefly of pmethoxycinnamic acid, together with smalleramounts of cinnamic acid and another compound which could notbe identified.The original aqueous liquid, after being extracted with amylalcohol as above described, was concentrated somewhat, and treatedwith a slight, excess of a solution of basic lead acetate.A copiousbrown precipitate was thus produced, which ww collected, wellwashed with water, then suspended in water, decomposed byhydrogen sulphide, and the mixture filtered.The filtrate, whenconcentrated, was dark reddish-brown, and appeared to containonly tannic and colouring matter.The liquid from the basic lead acetate precipitate was treatedwith hydrogen sulphide for the removal of the lead, and the filteredliquid concentrated to a small bulk. To the syrup thus obtaineTHE CONSTlTUENTS OF LEPTANDRA. 1949a large volume of alcohol was added, when a quantity of acrystalline substance was deposited, which was collected, washedwith a little alcohol, and dried. The liquid from which this crys-talline substance had been separated was deprived of alcohol, andevaporated to the consistency of a syrup. It evident,ly contained alarge amount of a sugar, since it readily reduced Fehling's solution,and yielded d-phenylghcosazone, melting at 209-211O.Isolation of d-Nannito2.The crystalline substance above described, which amounted to120 grams, or 2.14 per cent. of the weight of the drug, was r ecrystallised from alcohol, when it separated in needles, melting a t165--166O, and proved to be d-mannitol.(Found, C=39.5 j H= 7.8.Calc., C=396; H=7*7 per cent.)Further confirmation of the identity of the above-describedsubstance with mannitol was obtained by the formation of its acetyland benzoyl derivatives.On heating a little of the substance with acetic anhydride, aproduct was obtained which, when crystallised from absolutealcohol, separated in octahedra, melting at 122-124O, and consistedof the hex%acetyl derivative of mannitol.Another portion of the substance was benzoylated by theSchotten-Baumann method, as employed by Panormoff (J.Russ.Phys. Chem. SOC., 1891, 23, 375), when a product was obtainedwhich w a soluble in chloroform, but, on the removal of the solvent,formed a syrup. On dissolving this, however, in a small volume ofether, it yielded a mass of needle-shaped crystals, which melted a t149O, and after recrystallisation from a mixture of ethyl acetateand alcohol, or from acetic anhydride, the melting point remainedunchanged. (Found, C = 71.3 ; H = 4.9. Calc., C = 71.4 ; H = 4-7per cent.)This substance is thus seen to be hexabenzoylmannitol,C6H806(CO*C6H5)6, the melting point of which has been 'given as149O by Skraup (Monatsh., 1889, 10, 389) and by Panormoff (Zoc.c i t .) , but was incorrectly recorded by Stohmann, Rodatz, andHerzberg ( J . pr. Chem., 1887, [ii], 36, 354) as 124-125O.The optical rotatory power of hexabenzoylmannitol does notappear to have previously been recorded, and this was thereforedetermined, with the following result :0.4238, made up to 20 C.C. with chloroform, gave a, +2O9f in a2-dcm. tube, whence [a], '+ 50-7O.If the benzoylation of mannitol is conducted in the usual manner,by adding the benzoyl chloride in small quantities at a time, adibenzoyl derivative, C6H1206(CO*C6H,),, is obtained. This is ver1950 POWER AND ROQERSON:sparingry soluble in the usual organic solvents, and crystallises insmall, prismatic needles, which melt at 178-180°. (Found,C=61*0; H=5*8.0.3410, made up to 20 C.C.with pyridine, gave a, +Oo22/ in a,2-dcm. tube, whence [a], + 10'7O.Dibenzoylmannitol has previously been obtained by Einhorn andHollandt (9nnaZen, 1898, 301, l02), who recorded ih meltingpoint as 178O. On adding an excess of benzoyl chloride to a hotsolution of mannitol in pyridine, according to the method of thelasbmentioned investigators, a crystalline substance began toseparate at once, which was evidently the dibenzoyl derivative.When, however, the liquid was heated a little longer, a vigorousreaction ensued, which soon subsided, and a perfectly clear solutionwas obtained. The product was then poured into water andextracted with ether, when a substance was obtained which melteda t 149O, and proved to be hexabenzoylmannitol.Calc., C=61.5; H=5.6 per cent.)Examination of the Resin (B).This was a dark brown, brittle mass, and amounted to abouti350 grams, being thus equivalent to 6.2 per cent.of the drug. Itwas dissolved in alcohol, mixed with purified sawdust, and themixture successively extracted in a Soxhlet apparatus' with lightpetroleum (b. p. 35-50°), ether, chloroform, ethyl acetate, andalcohol.Petroleum Extract of the Resin.Theextract was dissolved in ether, and the ethereal solution shakenwith aqueous ammonium carbonate, which, however, removed onlya small amount of resinous material, together with a trace of3 : 4-dimethoxycinnamic acid. The ethereal solution was thenshaken with aqueous potassium carbonate, and the alkaline liquidacidified, when a quantity of black, tarry material was precipitated.This was distilled several times under diminished pressure, when aproduct was finally obtained which passed over between 220° and240°/15 mm.as a light yellow oil, and partly solidified on cooling.The free acids thus obtained amounted to 3.7 grams, and wereexamined together with the combined acids which will subsequentlybe described.After treatment with potassium carbonate, as above described,the ethereal solution was shaken with aqueous potassium hydroxide,which, however, removed nothing. On finally evaporating the ether,a residue was obtained, which was hydrolysed by heating with analcoholic solution of potassium hydroxide. The alcohol wm thenThis was a dark brown mass, amounting to 24.5 gramsTHE CONSTITUENTS OF LEPTAKDRA. 1951removed, and the cooled, aqueous, alkaline liquid extracted withether, the ethereal liquid being dried and the solvent evaporated.On dissolving the residue in alcohol, a small quantity of a solidseparated, which, when recrystallised from ethyl acetate, melted at62-65O, and was found to consist of a hydrocarbon and an alcohol,but the amount was too small tor permit of their separation.Zsolation of a Phytosterol, Verosterol, C2,H,,0,H,0;The alcoholic filtrate from the above-mentioned solid was con-centrated to a small bulk, when, after two or three days, a quantityof a crystalline substance separated. This was collected, washed,and recrystallised from a mixture of ethyl acetate and dilutealcohol, when it separated in flat needles, melting a t 135--136O,and gave the colour reactions of the phytosterols :0.2500, on heating at l l O o , lost 0.0126 H20.0.1230 * gave 0.3764 CO, and 0.1360 H,O.H;O=5*0.C=83*5; H=12*3.C27H,,0,H20 requires H20 =4*5 per cent.C,,H,,O requires C=83*9; H=11.9 per cent.A determination of its optical rotatory power gave the followingresult :0*2374,* made up to 20 C.C.with chloroform, gave a, -0O47' in a2-dcm. tube, whence [uJD -33.0'.A small amount of the phytosterol waa converted into its acetate,which separated from acetic anhydride in flat needles, melting atThe above-described phytosterol evidently represents a memberof this class of substances which is widely distributed in nature,and compounds possessing practically the same physical charactershave previously been obtained in these laboratories from varioussources, such as olive bark, wild cherry bark, and jalap (Trans.,1908, 93, 909; 1909, 95, 246; J .Amer. Chenz. SOC., 1910, 32, 87;compare also Menozzi and Moreschi, Atti R . Accad. Lincei, 1910,[v], 19, i, 187). I n view of these facts, and in order to distinguishthe abovedescribed phytosterol from sitosterol, which differs bythe higher melting point of its acetate (Monutsh., 1897, 18, 551),it would appear desirable to assign to it a specific name. It istherefore proposed to designate it verosterol, with reference t o thegeneric name of the plant, Veronica, from which it has now beenobtained.Identification of the Fatty Acids.The alkaline liquid, which had been extracted with ether asabove described, was acidified, and the liberated fatty acids collected,* Anhydrous substance.119-120'1952 POWER AND ROGERSON:dried, and distilled under diminished pressure, when they passedover between 220° and 250°/15 mm. as a pale yellow oil.Theacids t.hus obtained, which amounted to 4.2 grams, were mixed withthe previously mentioned portion of acids present in the free state,and the whole converted into their lead sa.lts, the latter being thendigested with ether, when a portion was dissolved. Both thesoluble and insoluble portions were decomposed by hydrochloric acid,and the regenerated fatty acids purified by distillation underdiminished pressure. The soluble portion of the lead salts yielded4.2 grams of liquid acids, whilst, the insoluble portion gave 3.3 gramsof solid acids.The Liquid A cids.-These acids, when distilled under diminishedpressure, passed over between 215O and 235O/15 mm.i19 a yellowoil. An analysis and a determination of the constants gave thefollowing results :0.1738 gave 0.4842 CO, and 0*€788 H,O.0.3788 absorbed 0-4872 iodine.0.1540 neutralised 0.0307 EOH.C = 76.0 ; H = 11.4.Iodine value = 128.6.Neutralisation value = 199.3.C18H3402 requires C = 76.6 ; H= 12.1 per cent. Iodine value= 90.1 ;C,,H,O, requires C = 77.1 ; H = 11.4 per cent. Iodine value = 181.4 ;It is evident from the above results that the liquid acids con-sisted of a mixture of oleic and linolic acids.The Solid A cids.-These acids, after being again distilled underdiminished pressure, were 'crystallised twice from ethyl acetate,when they melted at 54-56O:Neutralisation value = 198.9.Neutralisation value = 200.4.0.1512 gave 0-4190 CO, and 0.1728 H,O.C=75-6; H=12.7.0.2864 neutralised 0.0590 KOH. Neutralisation value = 206.C,,H3,O, requires C = 75.0 ; H = 12.5 per cent.Neutralisation value= 219.1.C,,H3,02 requires C = 76.1 ; H = 12-7 per cent.Neutralisation value = 197.5.These results indicate that the solid acids consisted of a mixtureof palmitic and stearic acids in about equal proportions.Ethereal Extract of the Resin.During the extraction of the resin with ether a quantity of asparingly soluble, yellowish-brown substance was deposited, andwhen the extraction was complete this wits collected, washed withether, and dried, when it was found to weigh 5 grams.It wasentirely amorphous, and proved t o be similar in character to theproduct extracted from the original aqueous liquid by amyl alcoholTHE CONS’L‘I‘I’UENTS OF LEPTAXDRA. 1953which has already been described. On heat,ing with aqueoussodium hydroxide, it yielded pmethoxycinnamic acid, which wassubsequently obtained in larger amount from the chloroformextract of the resin.The portion of extract which was more readily soluble in etherconsisted of a dark resinous mass, amounting to 95 grams. Itwas thoroughly examined, but nothing except a small quantity of3 : 4-diinethoxycinnamic acid could be isolated from it.Chloroform Extract of the Resin.This was a dark-coloured resinous mass, weighing 135 grams.Itcould easily be reduced to a fine powder, which was tasteless. Thechloroform solution of the resin was shaken with aqueous ammoniumcarbonate, when a small quantity of 3 : 4-dimethoxycinnamic acidwas removed. The liquid was then shaken with it solution ofsodium carbonabe, but only a small amount of a resinous productwas obtained.Isolation of p-Methoxycinnamic A cid, OMe*C,H,*CH:CH*C02H.After treating the chloroform liquid with the alkaline carbonates,as above described, it was shaken with successive portions of it10 per cent. solution of sodium hydroxide. These liquids wereunited and acidified, when a large quantity of a black, resinousproduct was precipitated.This resinous product was then treatedwith chloroform, in which it only partly dissolved. The chloroformsolution was shaken with aqueous sodium carbonate, and thealkaline liquid acidified, when a crystalline precipitate was obtained.It was thus evident that on shaking the original chloroform liquidwith alkali hydroxide, some constituent of it had been hydrolysed.The crystalline precipitate was collected, washed, and dried, whenit amounted to 14 grams. By fractional crystallisation from ethylacetate, it was found t o consist of a mixture of 3 : 4-dimethoxy-cinnamic acid and an acid which separated in iridescent, prismaticneedles. The lakter melted a t 170°, assuming a (( liquid-crystalline ”phase, which persisted until the temperature of 181-182O wasreached, when it passed into the ordinary liquid state.The“crystalline” character of the liquid between 170° and 181O wasconfirmed by observing it through crossed Nicol’s prisms. The last-mentioned acid was analysed. (Found, C = 67.3 ; H = 5.8 ;OMe = 17.3.In order further to characterise this acid, its methyl ester wasprepared. This was accomplished by boiling a solution of the acidin methyl alcohol .with a few drops of concentrated sulphuric acidCalc., C = 67.4 ; H = 5.6 ; OMe= 17.4 per cent.1954 POWER AND ROCIERSOK:for about two hours on the water-bath. The product so obtainedwas recrystallised from absolute alcohol, when it separated in flatneedles, melting at 88-90°.The above results render it evident that the subst’ance underexamination was pmethoxycinnamic acid, which appears only oncepreviously to have been observed to occur in nature.I n the formof its ethyl ester, it was found by van Romburgh t o be the chiefconstituent of the essential oil of Xaernpf eria galanga, Linn6 (Proc.K . Akad. Wetensch. Amsterdam, 1900, 3, 38; 1902, 4, 618;Schimmel’s Bericht, Oct., 1900, p. 37, and April, 1903, p. 38).As it appears not to have previously been recorded thatp-methoxycinnamic acid shows, on heating, a (( liquid-crystalline ”phase, it was deemed desirable to confirm this observation by meansof the synthetically prepared acid. For this purpose a smallquantity of p-coumaric acid was methylated by means of methylsulphate, and the product recrystallised from ethyl acetate, whenit separated in prismatic needles, melting to the ‘( liquid-crystalline ”phase at 170°, and then passing to the ordinary liquid state a t181-182O.A mixture of the naturally-occurring and syntheticacids likewise showed exactly the same behaviour at the same tem-peratures, and their identity was therefore definitely established.The chloroform liquid from which the above acids had beenisolated was finally evaporated for the removal of the solvent. Aresinous product was thus obtained, from which, however, nothingcrystalline could be isolated.Et?bcyl Acetate and Alco?boZ Extracts of the Resh.These extracb were dark, resinous products, amounting to 77.5and 32.0 grams respectively. They were heated with a 5 per cent.solution of sulphuric acid in aqueous alcohol, but, with the exceptionof a, smsll quantity of sugar yielding d-phenylglucosazone (m. p.209-210°), nothing definite was obtained.Summary.The results of the present investigation may be summarised asThe material employed was commercial (‘ leptandra,” consisting.follows :of the rhizome and roots of Veronica virginica, Linn6 (Leptandrauirginica, Nuttall).An alcoholic extract of this material, when distilled with steam,yielded an amount of essential oil equivalent t,o 0.16 per cent.ofthe weight of the drug. This essential oil was a dark brow0 liquid,which distilled between 120° and 16Ooj25 mmTHE CONSTITUENTS OF LEPTANDRA. 1955The portion of the extract which was soluble in water contained3 : 4-dimethoxycinnamic acid, a quantity of mannitol, amounting to2-14 per cent.of the weight of the drug, and a sugar which yieldedd-phenyIglucosazone (m. p. 209-211°), together with some tannicand colouring matter. It yielded, furthermore, a quantity of abrown, amorphous product, which possessed an intensely bitter,nauseous taste, and amounted to 1.6 per cent. of the weight of thedrug. By the hydrolysis of this product there were obtained,besides resinous material, cinnamic and p-methoxycinnamic acids.The portion of the extract which was insoluble in water consistedchiefly of a dark brown resin, which amounted to 6.2 per cent. ofthe weight of the drug. From this resin the following substanceswere obtained: A phytosterol, C2,H,,0 (m. p.135-136O;[aID -33*Oo), which it is proposed to designate verosterol; a mix-ture of fatty acids, consisting apparently of oleic, linolic, palmitic,and stearic acids ; p-methoxycinnamic acid, which was present inthe form of an ester; and a very small amount of 3 : 4-dimethoxy-cinnamic acid, which had probably been occluded by the resin.It htts been observed that p-methoxycinnamic acid, when melted,passes into a, ‘‘ liquid-crystalline ” phase, which persists until atemperature of 181-182O is reached.It has not been possible to confirm the statement recorded inthe literature that leptandra ” contains a crystalline, bitterglucoside, designated as “ leptandrin,” to which its activity maybe attributed. Steinmann (Amer. J . Pharm., 1887, 59, 229)obtained from “leptandra,” in an amount of about 0.1 per cent.,a, crystalline, yellow substance, which possessed a, very bitter taste,and was found not to be a glucoside, although it was not furthercharacterised. From the method by which this substance wasisolated, itl appears highly probable that it consisted of 3 : 4-di-methoxycinnamic acid, contaminated with a little of the above-mentioned, bitter, amorphous product. The fact that an aqueoussolution of this product froths strongly on agitation has doubtlessled to the statement recorded in the literature that ((leptandra”contains saponin.Some tests with preparations of (‘ leptandra,” which were kindlyconducted for us by Dr. E. H. Dale, Director of the WellcomePhysiological Research Laboratories, led to the following conclusions.Both the crude resin and the bitter, amorphous product obtainedfrom the portion of the alcoholic extract which was soluble in waterwere administered by the mouth to dogs, in doses of 1 gram each,but without any visible effect The bitter, amorphous product wasalso tested on the mammal by intravenous injection, ,and on theisolated mammalian heart, but no characteristic action could b1956 MAY: AROMATIC ANTIMONY COMPOUNDS. PART I.observed. Although the total alcoholic extract of the drug, whengiven to a dog in doses of 5 grams, produced vomiting, this maybe attributed to its nauseous taste and irritant effect on the stomachrather than to any specific action.THE WELLCOME CHEMICAL RESEARCH LABORATORIES,LONDON, E.C

ISSN:0368-1645    

DOI:10.1039/CT9109701944

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

1956 MAY: AROMATIC ANTIMONY COMPOUNDS. PART I.CCVI1.-Aromatic Antimony Compounds. Part I.The Oxidation and Nitration of Triphenylstibine.By PERCY MAY.VARIOUS aromatic derivatives of antimony of the type R,Sb andR,SbX,, in which R represents phenyl, tolyl, anisyl, etc., and Xrepresents C1, Br, NO,, or OH, have been prepared by Michaelisand his pupils (Michaelis and Reese, AnmaZen, 1886, 233, 5 2 ;Michaelis and Genzken, Annalen, 1887,242,176; Loloff, Ber., 1897,30, 2834), but nevertheless far less work has been carried out withthese compounds than with the corresponding derivatives of arsenic.Michaelis and Reese showed that the compound (C,H,),Sb(OH), isamphoteric in character, and it therefore appeared to be of interestto observe the effect of the introduction of a nitro-group on therelative stability of the various compounds, such as R,SbCI,,R,Sb(OR),, R,Sb(NO,),.Michaelis and Reese prepared the com-pound (C,H,),Sb(N03)2 by the action of nitric acid on triphenyl-stibine, but if, at the same time, a nitregroup could be introducedinto the benzene nuclei, the basicity of the compound R,Sb(OH),might be so depressed that a nitrate such its R,Sb(NO,), could nolonger be formed, and the resulting compound might be of the typeR,Sb(NO,) (OH).On nit ration, triphenylstibine yields t rinit ro t riphenyls ti b i n e di-hydroxide, (C,H,*NO,),Sb(OI~),. It does not appear to be capableof forming a stable sulphate or nitrate, but a chloride has beenprepared, and it therefore appeared to be desirable to obt,ain somefurther information as to the relative stability of the parentsubstance, (C,H,),Sb~OH),, and its salts, and, if possible, to preparethe hitherto unknown normal sulphate, (C,H,),SbSO,.Triphenyl-stibine readily reduces concentrated sulphuric acid, with theformation of the desired sulphate, thus :(C6H,),Sb + 2H2S04 = (C6H,),SbSO4 + so, + 2H20,and this compound could also be obtained by dissolving the correMAY : AROMATIC ANTIMONY COMPOUNDS. PART I. 1057sponding hydroxide in concentrated sulphuric acid. Dilutesulphuric acid does not attack triphenylstibine, but permanganateand dilute sulphuric acid oxidise it to the hydroxide,(C,H,),Sb(OH),. This reaction is of interest from a twofold pointof view. On the one hand, it indicates that the sulphate is far lessstable than the chloride,* and, on the other hand, it affords freshevidence of the great stability of the molecule of triphenylstibineas a whole.I f alkaline permanganate be used as the oxidisingagent, a better yield of the dihydroxide is obtained. Michaelis andReese state that solutions of this substance in alkali are repre-cipitated by mineral acids, but on repeating these experiments itwas found that dilute nitric or sulphuric acids produced noprecipitate, whilst hydrochloric acid caused precipitation even invery dilute solutions. Probably the experiments of Michaelis andReese were confined t o halogen acids. Similarly, solutions of tri-phenylstiibine sulphate and nitrate in the corresponding con-centrated acids can be diluted indefinitely, although these substancesthemselves are insoluble in dilute acids, but, on addition of dilutehydrochloric acid t o their dilute solutions, an immediate precipitateof the chloride is obtained.The introduction of a nitro-group into the benzene nuclei of thecomplex R,Sb(OH), not only reduces the salt-forming power ofthe molecule, but also lowers its stability as a, whole.This isshown by the fact that the trinitro-derivative is partly decomposedwhen boiled with aqueous alkali, yielding a, small quantity ofnitrobenzene.EXPERIMENTAL.The triphenylstibine used in this investigation was prepared byMichaelis and Reese’s method, shortened and simplified in some ofits detai1s.t The long method of purification after extraction withalcoholic hydrochloric acid, described by these authors, was omitted,the product being instead directly recrystallised from lightpetroleum.Pure triphenylstibine was thus obtained, the yieldbeing 70 per cent.. of the theoretical. The material contained inthe petroleum mother liquor was converted into the dichloride,which, after recrystallisation, was still contaminated with traces ofan impurity having an extremely irritant action on the mucousmembrane. This was finally removed by dissolving the product inconcentrated sulphuric acid, pouring the product into aqueousalcohol, and setting aside to crystallise.* Triphenylstibine hydroxide combines readily with dilute hydrochloric acid,forming the dichloride.f A stock solution of dry antimony chloride in dry benzene, made up for thesepreparations, gradually acquired a deep magenta collour cven in the dark1958 MAY: AROMATIC ANTIMONY COMPOUNDS.PART I.A7itration of Triphenylstibine and Preparation of Trinitrophenpl-s t i b in e Dih y dr o xid e, (C0H,-N02)3Sb (OH),.Triphenylstibine was added, in small quantities a t a time, to anexcess of a mixture of three parts of sulphuric acid and one partof nitric acid, a t about 40°. When cold, the mixture was pouredinto ice-water, the temperature being kept below 25O. Theyellow precipitate thus obtained was recrystallised from glacialacetic acid, in which it is very soluble, and separates in flat,transparent, pale yellow crystals, melting at 190-191O. It is alsosoluble to some extent in alcohol or ether, but does not crystallisewell from these solvents.It is insoluble in water, and almostinsoluble in benzene, light petroleum, etc. :Found, C= 41.74 ; H = 2-91 ; N = 7.79, 7.91 ; Sb = 22-06.C,,H,,O,N,Sb requires C = 41.5 ; H = 2.72 ; N = 8.07 ;Sb = 23.11 per cent.On treatment with Devarda’s alloy no ammonia is evolved.When boiled with glacial acetic acid and zinc dust, or with alcohol,hydrochloric acid, and tin, it yields an easily diazotisable amine,which was not further investigated, as work on this compound isbeing carried out by Morgan, Micklethwait, and Whitby (Proc.,1910, 26, 151).TTinit rop henylstib ine Dichloride, (C,H,~NO,),SbCl,.This compound is formed, together with the hydroxy-chloride, byboiling trinitrophenylstibine dihydroxide with alcoholic hydro-chloric acid.After recrystallising, the product still appeared tobe impure, and analysis indicated that it was a mixture of thedichloride and the hydroxy-chloride. The pure dichloride wasobtained by the direct nitration of triphenylstibine dichloride,which was dissolved in concentrated sulphuric acid, and thennitrated in the same manner as triphenylstibine. It separatesfrom glacial acetic acid in clusters of small crystals, melting at157O, which are readily soluble in concentrated nitric acid or glacialacetic acid. As this substance was only obtained in small amount,its properties were not further investigated.Found, C1= 12.37.C,8H,,06N,C1,Sb requires c1= 12.73 per cent.Triphenylstibine Sulphate, (C6H,)3SbS0,.Five grams of triphenylstibine were warmed with an excess ofconcentrated sulphuric acid on the water-bath.A vigorous reactionsuddenly set in, sulphur dioxide being evolved, and a white p r MAY: AROMATIC ANTIMONY COMPOUNDS. PART I. 1959cipitate formed, which was filtered on asbestos, and washed withcold alcohol, a portion being afterwards extracted with this solvent-,in which it is only very sparingly soluble. Sniall crystals were thusobtained, and similar crystals separated on evaporation of themother liquor after dilution with water. These crystals melt above300°, and are soluble in concentrated sulphuric acid, very sparinglyso in alcohol, and insoluble in water, dilute sulphuric acid, and mostother solvents.The substance is decomposed by warming withaqueous sodium hydroxide, forming sodium sulphate and triphenyl-stibine hydroxide, the latter dissolving in the excess of alkali :Found, S = 7-30.Cl8H1,O4SSb requires S = 7-17 per cent.A solution of the sulphate in sulphuric acid may also be obtainedby dissolving triphenylstibine hydroxide in the concentrated acid,and this solution, as also the sulphuric acid mother liquor mentionedabove, can be largely diluted without any precipitation occurring,but on adding a drop of hydrochloric acid t o solutions of anyconcentration, a precipitate is formed, which, after recrystallisationfrom alcohol, was found to have the characteristic crystalline formand melting point of triphenylstibine dichloride.Oxidution of Triphenylstibine with Permanyanate.(1) In Alkaline Solution.-Triphenylstibine was boiled for threehours with alkaline permanganate, the manganese dioxide removed,and a portion of the filtrate acidified with hydrochloric acid.Awhite precipitate was produced, wb?ch was recrystallised from alcoholand found to be triphenylstibine dichloride. Another portion ofthe filtrate was acidified with dilute sulphuric acid, and in thiscase no precipitate was formed. Evidently the first product ofthe oxidation is triphenylstibine hydroxide, which dissolves in thealkali, giving solutions from which hydrochloric acid precipitatesthe chloride, but which are not precipitated by sulphuric or nitricacids.(2) In, A cid Solution.-Five grams of triphenylstibine werewarmed on the water-bath with an excess of 1 per cent. per-manganate and dilute sulphuric acid.The permanganate wasgradually decolorised with a slight evolution of carbon dioxide ;more permanganate was added from time t o time, and finally theprecipitate was collected and extracted with alcohol. I n this way,a small quantity of a substance was obtained which melted at210°, contained no sulphur, and appeared to be identical withtriphenylstibine hydroxide, as prepared by Michaelis and Reese.This substance was obtained by them in the form of an amorphouspowder, but a modification of their method of preparation led t1960 KENNER AND WITHAM : TOLANE DERlVATIVES FROMits being obtained in a well-crystallised state. An alcoholic solutionof triphenylstibine dichloride was added t o an equal volume of2177-aqueous sodium hydroxide, and the mixture set aside. Aftersome days, triphenylstibise hydroxide crystallised out in beautifulleaflets, which were washed with water and dried. The productwas then found to melt at 210°, and resembled the productobtained by Michaelis and Reese in its behaviour towards reagents.I wish to express my thanks to Sir William Ramsay and toProfessor Collie for the interest they have taken in this work, andto the Research Fund Committ.ee of the Chemical Societ,y for agrant towards the expenses thereof.UNIVERSITY COLLEGE,LONDON

ISSN:0368-1645    

DOI:10.1039/CT9109701956

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

1960 KENNER AND WITHAM : TOLANE DERlVATIVES FROMCCVIII.--T/ze Fwmation of Tolam Derivutives fromp- Chloq-otoluene and 3 : 4-Dicldorotoluene.By JAMES EENNER and ERNEST WITHAM.As is well known, the chlorination of toluene at its boiling pointleads to the formation of benzotrichloride. On one occasion, how-ever, Liebermann and Homeyer (Ber., 1879, 12, 1971), and laterGattermann (Ber., 1884, 17, 2601), observed the formation of asolid substance as chief product during this reaction, and identifiedit as tolane tetrachloride, which had previously been obtained byZinin by the action of phosphorus pentachloride on benzil.During the preparation of chlorobenzylidene chlorides fromp-chlorotoluene and 3 : 4-dichlorotoluene, Armstrong and Wynnesimilarly obtained products which were identified as di- and tetra-chloro-tolane tetrachlorides. The present authors have also hadthe same experience in preparing pchlorobenzotrichloride fromp-chlorotoluene, but, in common with earlier investigators of thisreaction, they have failed to find a clue to the conditions whichlead to the formation of the tolane derivative.Liebermann and Homeyer (Zoc. cit.), it is true, attributed thecondensation to sulphuric acid which had been carried over into themixture, but in the case of the authors’ experiments such anexplanation is improbable, as the gas, after being passed throughsulphuric acid, was led through a tube packed with asbestos, and,moreover, the introduction of sulphuric acid into the boilingchlorotoluene has not been found to initiate the condensation.This is the more unfortunate as the only other general methoP-CIILOROTOLUEKE AND 3 : ~-~IC€ILOI~OTOLUENE.1961of preparing tolane tetrachloride and its derivatives is that usedfirst by Hanhart (Ber., 1882, 15, 899), which consists in the removalof chlorine from benzotrichloride by the action of copper powder,and does not give satisfactory results, either as regards yield orpurity of product. Hanhart, apparently unable to isolate anydefinite substance from the tarry product, had recourse to dis-tillation, and obtained the two forms of tolane dichloride, nowrecognised as the stereoisomerides :Onufrowicz (Ber., 1884, 17, 833), who succeeded in isolating thetetrachloride, showed a t the same time that it could be convertedinto cis-tolane dichloride by distillation, thus explaining Hanhart’sresult.Later, Fox (Ber., 1893, 26, 653), without reference to Onufrowicz’spaper, carried out the same reaction with o-chlorobenzotrichloride,and distilled the product, obtaining the cis- and trans-2 : 2/-dichloro-tolane dichlorides.The authors have repeated Fox’s work in thehope of separating the tetrachloride, but have been unable to findany evidence of its production, and, as recorded on p. 1966,succeeded, as he did, in isolating only the dichlorides.As p-chlorobenzotrichloride, unlike the o-derivative, forms thetetrachloride, which can be isolated without difficulty, the oppor-tunity was taken of testing the applicability of the decompositionobserved by Onufrowicz to substituted tolane tetrachlorides.Aswas expected, 4 : 4/-dichlorotolane tetrachloride, when distilled,behaves in a precisely similar manner to tolane tetrachloride, andyields the cis-form of the dichloride.Further, the tetrachloride was submitted to reduction, and resultsof some interest were obtained. Zinin (Ber., 1871, 4, 289) showedthat the action of zinc on alcoholic solutions of tolane tetrachlorideled to the formation of the stereoisomeric dichlorides. Liebermannand -Horneyer (Bey., 1879, 12, 1971) used zinc dust in place ofzinc, and obtained the same products, whilst Lachowicz (Ber., 1884,17, 1165) subsequently arrived at the same result by reducing a,boiling concentrated acetic acid solution with iron filings.Wislicenus and Blank (Annalen, 1888, 248, 1) repeated Zinin’swork, and Eiloart (Amer.Chem. J., 1890, 12, 239), who studiedthe two dichlorides from the stereochemical point of view, upheldthe opinion already expressed by Wislicenus (Zoc. cit.), that theless soluble isomeride, with the higher melting point, was the cis-form, although it may be remarked that this is contrary to theusual rule.VOL. XCVLI. 6 1962 KEKNER AND WITHAM : TOLANE DERIVATIVES FROMThe reduction products obtained from 4 : 4’-dichlorotolane tetra-chloride in alcoholic solution by means of zinc dust vary accordingto the temperature employed, I f conducted at 50°, the productsare the two 4 : 4’-dichlorotolane dichlorides, which respectivelymelt a t 166-167O and 86--87O, and, in addition, 4: 4/-dichloro-tolane; but if carried out at the boiling point of the alcoholicsolution, the isomeride melting at 166-167O can no longer be found,the reduction products being the dichloride of lower melting pointand 4 : 4/-dichlorotolane.If the conclusions drawn by Wislicenus and Blank respectingthe cis- and trans-isomerism of the tolane dichlorides can be accepted,then it will follow by analogy that the dichlorotolane dichloride,melting at 166-167O, will be the cis-form.The entire absence ofthis isomeride from the reduction product obtained by working atthe higher temperature, and the evidence that, unlike the dichloride(m. p. 86--87O), it is readily reduced may perhaps be regarded assupporting this view.As already mentioned, tolane tetrachloride was originallyobtained by Zinin by the action of phosphorus pentachloride onbenzil, and this would doubtless provide a general method of pre-paration were it not that, as is well known, the isolation of thebenzoins which should furnish the benzils on oxidation has beenaccomplished only in a few instances.Especially is this the casewhere negatively substituted aldehydes are submitted to the benzoinreaction. The authors hoped to use o-chlorobenzaldehyde as thestarting point for the preparation of the 2 : 2/-dichlorotolane tetra-chloride, which could not be isolated in the experiments alreadymentioned, but found that when the benzoin condensation wasattempted, o-chlorobenzoic acid was the chief product. Greatersuccess attended experiments with p-chlorobenzaldehyde, foralthough the product of the benzoin condensation was a resinousmass from which the pure substance could not be isolated, oxidationwith nitric acid led to the production of the 4 : 4’-dichlorobenzil,identical with the substance obtained by hydrolysing 4 : 4/-dichloro-tolane tetrachloride with acetic acid by Liebermann and Homeyer’smet hod.It has not hitherto been possible to apply the reaction to thepreparation of 2 : 2/-dichlorobenzil, because the attempt to prepare2 : 21-dichlorotolane tetrachloride by the chlorination of the cis-dichloride merely led to the conversion of the greater part into themore stable trans-form.Chlorine is known to be a particularlyeffective agent f o r the interconversion of stereoisomerides.Liebermann and I-Iomeyer (Zoc.cit.) confirmed Limpricht”s statementthat the tolane dichlorides were stable towards acetic acid, and thP-CHLOROTOLUENE AND 3 : 4-DICRI.OROTOLt7EKE. 1963present authors found the same to hold good for the 2 : 2’-dichloro-tolane dichlorides.E X P E R I Bf EN T A L.*Armatrong and Wynne (private communication), in the pre-paration of p-chlorobenzylidene chloride from p-chlorotoluene,employed chlorine prepared from manganese dioxide and hydro-chloric acid, washed by passage through water, and dried oversulphuric acid. For each of seven operations, 126 grams of p-chloro-toluene were used, and it was found that in the first two only avery small quantity, but ih the last five, considerable amounk, of4 : 4’-dichlorotolane tetrachloride separated in a crystalline formon cooling.The rate at which the chlorine was absorbed did notseem to influence the tolane condensation: thus, in the first twoand the last two operations the figures f o r increase in weight due tochlorination and, in brackets, the duration in hours were 74 (16),71 (15), 70 (14), 67 (16)-the calculated increase in weight being69 grams.The present authors have used liquid chlorine obtained fromKahlbaum as the source of the gas, and have passed the chlorinethrough sulphuric acid (to allow of the rate being checked) andasbestos wool before introducing it into the boiling p-chlorotoluene.With one exception they have been unsuccessful in obtainingthe 4 : 4’-dichlorotolane tetrachloride.Throughout, they havechlorinated to the stage of p-chlorobenzotrichloride, and the usualdaily increase in weight was 15 grams, but on the one occasionwhen the tetrachloride was formed, 44 grams on the first day, and22 on the second, were taken up. The yield of the tetrachloridefrom 100 grams of p-chlorotoluene was 44 grams, and the motherliquor consisted of 21-chlorobenzotrichloride. All attempts t o repeatthe conditions leading to the formation of the tolane derivativehave been unsuccessful.4 : 4’ - Dic7dorotoZane tetrachloride, C,I~,C1*CCl,*CC12’C,H,CI,crystallises from chloroform in thin, well-defined, flat plates. Itmelts at 190°, and dissolves only sparingly in alcohol, but readilyin chloroform, benzene, or light petroleum :(P) 0.5923 gave 0.9367 CO, and 0.1212 H@. C =43.13; H = 2.27.0.327 ,, 0.7216 AgC1.Cl=54.58.C,,H&& requires C = 43.19 ; H = 2.06 ; C1= 54.75 per cent.* The study of 4 : 4’-diclilorotolane tetrachloride was begun by Mr. S. Parrish,B.Sc., a t the Royal College of Science. He examined its reduction prodncts,obtninillg the cis- and trans-4 : 4’-dichloroto~ane dichlorides, and prepared from it4 : 4’-dichlorobeuzil and the corresponding hydrazone. Unfortunately, he wasunable to complete the work, and the investigation has been taken up afresh by thepresent authors. Analyses prefixed by the letter P were made by Mr. Parrish.-- w. P. w.6 ~ 1964 RENNER AND WITIIA&I : TOLASE DERIVA'rIVE3 FROM3 : 4 : 31 : 4'-Tetracl~lorotok~ne tetrachloride,C6H,C12* CCl,*CCl,= C,H,C12,is formed when 3: 4-dichlorotoluene is chlorinated to the stage of3 : 4-dichlorobenzylidene chloride under conditions such thatsulphuric acid used as drying agent could not be carried forwardmechanically (Armstrong and Wynne, private communication).The tetrachloride in this case did not separate on cooling, but wasisolated by extraction with chloroform from the semi-solid residueleft after fractionation of the 3 : 4-dichlorobenzylidene chloride(b.p. 274-275O). It crystallises from chloroform in small, diamond-shaped plates, which melt at 197O:0.1214 gave 0.3037 AgC1. C1= 61.88.C,,H,Cl, requires C1= 61.97 per cent.4 : 4'-Dicldorotot?ane Tetrachloride f r o m p-Chlorobennoti-i-To prepare the tetrachloride, p-chlorobenzotrichloride (40 grams),benzene (60 grams), and copper powder (30 grams) were boiled ina reflux apparatus for about six hours until the reaction seemedto be complete.The hot solution, freed from copper powder byfiltration, deposited crystals of the tetrachloride and of p-chloro-benzoic acid, the latter of which was removed by extraction withsodium carbonate solution. The yield of tetrachloride from 207grams of the trichloride amounted to 110 grams.On crystallisation from chloroform, it was obtained in platesidentical in appearance, melting point ( 190°), and composition(C1=54*58 per cent.) with the product formed during thechlorination of boiling p-chlorotoluene.When heated at 230°, the tetrachloride decomposes with theelimination of hydrogen chloride, and at a higher temperature,about 270°, chlorine also can be detected in the escaping gas.Thisdecomposition was studied inore closely by distilling 5 grams ofthe tetrachloride under a pressure of 90-130 mm. The firstportion of the distillate was a colourless liquid, which passed over at234O, but the remainder was solid, and, when crystallised fromacetone, formed small, rhombic crystals, which melted at 166-167O.This crystalline compound was subsequently identified as cis-4 : 4f-diclzlorotolane dichloride (p. 1965) :0-192 gave 0,3712 CO, and 0.045 H,O.c I& I o i d e.C =52*72 ; H= 2.60.C14H8C14 requires C = 52.85 ; H = 2-54 per cent.Reduction of 4 : 41-Dichlorotolane Tetrachloride.The reduction was carried out by suspending the tetrachloride(5 grams) in boiling absolute alcohol (500 c.c.), and addinP-CHLOROTOLUENE AND 3 : 4-DICEILOROTOLUENE.1965gradually during two days zinc dust (4 grams) and glacial aceticacid (30 c.c.). The solution, freed from zinc dust by filtration,deposited, on cooling, very thin, nacreous flakes, amounting in allto 1.5 grams.Concentration of the alcoholic filtrate to 150 C.C. furnishedmaterial amounting in all to 1.2 grams, which consisted of long,slender, brittIe, prismatic needles, and was identified as trans-4 : 4/-dichlorotoIane dichlorrde. Further concentration gave onlysmall, ill-defined separations, mixed with zinc acetate.By carrying out the reduction a t 50°, instmead of at the boilingpoint, a, third substance, crystallising in lustrous, thin, diamond-shaped plates, was obtained in addition to the other two.It wasidentified as cis-4 : 4/-dichlorotolane dichloride, but no estimatecould be formed of the relative proportion of the two isomeridesin the reduction product.cis-4 : 4/-DicldorotoZane dichloride, C6H4C1*CC1:CC1~C6H4Cl, is lesssoluble in alcohol than the trans-isomeride. It melts at 166-167O :(P) 0.1710 gave 0.3087 AgCI.When reduced in boiling alcoholic solution with zinc dust andtrans-4 : 4~-DichZorotoZane dichloride dissolves readily in alcohoI,ItC = 52.45 ; H = 2-70.On analysii, this proved to be 4 : 4’-dichlorotolane.C1=44*66.q4H8C14 requires C1= 44.62 per cent.acetic acid, it yields 4 : 4/-dichIorotolane.and separates from solution in characteristic, prismatic needles.melts at 86-87O:(P) 0.354 gave 0.6808 CO, and 0-0861 HiO.0’3347 ,) 0.5986 AgCl.C1= 44.25.C,,H,CI, requires C= 52.83 ; H = 2.52 ; C1= 44.65 per cent.4 : 4~-DichZorotoZane, C,H,Cl-CI C*c6H4cl, is much less soluble inalcohol than the two dichlorides, and appears to be dimorphous, asit crystallises from solution sometimes in nacreous flakes, and some-times in slender needles. Usually it melts a t 175--176O, but onone occasion the melting point first observed was 153-154O, which,after solidification of the specimen and re’-fusion, rose to andremained constant at 175-176O. On analysis of two differentpreparations :(i) 0.1626 gave 0.4064 CO, and 0.0518 H,O. C = 68.16 ; H =3*54.(ii) 0-1710 ,, 0.4262 CO, ,, 0.0458 H,O.C = 67.97; H =2-97.(i) 0.3517 ), 0.4080 AgC1. C1=28*70.C,,H8C1, requires C = 68.02 ; H = 3-26 ; C1= 28-72 per cent.Cl,Hl,Cl, ,, C = 67-47 ; H = 4-05 ; C1= 28.48 ),These analyses point. to the tolane formula, but the productionof a tolane, rather than a stilbene or dibenzyl derivative, by reduc-tion of the dichlorotolaae tetrachloride seemed sufficiently remark1966 KENNER AND WITHAM: TOLANE DERIVATIVES FROMable to require confirmation. Accordingly, chlorine was passedthrough a solution of the compound in chloroform until no moreof the gas was taken up, and, after removal of the solvent, it wasfound that the product consisted of 4 : 4/-dichlorotolane tetra-chloride in practically quantitative amount.Hence the conclusionis drawn that the reduction product is, as stated, 4: 4/-dichloro-tolane.The formation of a tetrachloride during the preparation ofo-chlorobenzotrichloride from o-chlorotoluene was not observed, andas attempts to make 2 : 2~-dichlorohenzil, which would have fur-nished a means of obtaining it, were unsuccessful, recourse was hadto FOX’S process in t,he hope that it might be isolated from theproduct of the action of copper powder on o-chlorobenzotrichloride.T T ~ a t m e n t of 0-Ch lor o b en xo t r i c h I o r ide with Copper Pow d e r.o-Chlorobenzotrichloride (20 grams) was dissolved in benzene(30 grams), and heated with copper powder (15 grams) for twenty-five hours in a reflux apparatus. After filtration, repeatedextraction of the residue with benzene, and removal of the benzeneby distillation, the residue was allowed to dry on a porous platefor a fortnight.In spite of many attempts with different solvents, it was notfound possible t o extract from this residue any substance otherthan o-chlorobenzoic acid (m.p. 136O). As a similar residue frombenzotrichloride, when heated at 200° with 80 per cent. acetic acid,gave a relatively large yield of benzil, a portion of this viscidsubstance was also heated with acetic acid, but furnished onlyo-chlorobenzoic acid. Yet when the part which had not gone intosolution in the acetic acid was dried and distilled, it gave bothcis- and trans-2 : 2’-dichlorotolane dichlorides. It is difficult toresist the conclusion that the tetrachloride is not formed in thecondensation, or, if formed, suffers decomposition into thedichlorides under the conditions of the experiment, being less stablethan the 4 : 4’-dichlorotolane tetrachloride, which requires t o beheated a t above 200° before decomposition into the dichloride takesplace.To confirm Fox’s results (Zoc.cit.), a portion of the viscid productwas distilled under 11 mm. pressure. Below 210° the distillatewas colourless, and solidified on cooling. By crystallisation fromlight petroleum, it was separated into two portions, the one con-sisting of clusters of radiate needles, melting at 136O, identicalwith o-chlorobenzoic acid, and the other of prismatic crystals,melting at 172-173O, which proved to be cis-2 : 2/-dichlorotolanP-CHLOROTOLUENE AND 3 : 4-DICEILOROTOLUENE. 1967dichloride (C1= 44.73 per cent.).The later distillate was brown,and, after purification, consisted for the most part of the cis-dichloride, whilst the residue in the flask, when extracted by lightpetroleum, yielded large, transparent rhombs, melting a t 127--128O,which agreed in properties with the description given of trans-2 : 2/-dichlorotolane dichloride (C1=44.5 per cent.).When the cis-2 : 2/-dichlorotolane dichloride is reduced in boilingalcoholic solution with zinc dust and acetic acid under the con-ditions already described for the 4 : 4/-isomeride, it is convertedinto 2 : 2/-dichlorotolane (m. p. 87O). The same substance is alsoformed when the dichloride is heated with copper powder at 260O.4 : 4’-Dic?dorob enail.-When 4 : 4’-dichlorotolane tetrachloride isheated with glacial acetic acid (40 c.c.) and water (10 c.c.) at 170°for six hours, it is converted into 4 : 4’-dichlorobenzil, whichseparates in the tube in long, slender, yellow needles, and whenrecrystallised from alcohol was found to melt at 193O.Montagne(Eec. trav. chim., 1902, [ii], 21, 19) gives the melting point as200° :C=59*60; H=3.09. (P) 0.3735 gave 0-8162 CO, and 0.1039 H,O.(P) 0.2318 ,, 0.2305 AgC1. C1=25*59.C,,H,O,Cl, requires C = 60.22 ; H = 2.89 ; C1= 25.42 per cent.Hantzsch and Glover obtained this compound from the corresponding benzoin, which was formed from p-chlorobenzaldehyde bythe benzoin condensation (Ber., 1907, 40, 1519). The quantitiesof materials used and the exact conditions are not given by them,and it may be of interest to note that while studying the benzoincondensation some years ago, Miss E. S. Hooper, B.Sc., failed toisolate the benzoin from this source, although the product, whenoxidised by nitric acid, gave a 40 per cent. yield of 4 : 4’-dichloro-benzil (m. p. 19l0), which wm identical with that obtained from4 : 4r-dichlorotolane tetrachloride (private communication).The rnonohgdrazone, C6H$l-C( :N*NH*CGH5) =CO*C,H,CI, crys-tallises from alcohol in small, yellow prisms, and melts at 178O:(P) 0.0965 gave 6.4 C.C. N, (moist) at 20.5O and 758 mm. N = 7-52.C2,H,,0N2Cl, requires N = 7.59 per cent.The authors wish to express their thanks to Professor Wynne,who directed their attention to this problem, and has given themmuch valuable assistance and advice during its investigation.THE UNIVERSITY,SHEFFIELD

ISSN:0368-1645    

DOI:10.1039/CT9109701960

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

1968 DEAKIN AND WII,SMOIiE : SOME REACTIONS OF KErEN.CCIX. --Some Reactions of Kiten.€Iyd?-ocyanic Acid.By STELLA DEAKIN and NORMAN THOMAS MORTIMER WILSMORE.IN a note published by Miss F. Chick and one of us (Proc., 1908,24, 77), it was stated, among other things, that keten combinedwith liquid hydrogen chloride under pressure at the ordinarytemperature to form acetyl chloride :CH,:CO + HCr= CH3*C?OCl,there being no evidence of the formation of the isomeric chloro-acetaldehyde or of its condensation product, dichloroethyl acetate.Under similar conditions keten also combined with hydrogensulphide, forming acetyl sulphide, the so-called thioaceticanhydride: *2CH2:C0 + H2S = (CH,*CO),S.Finally, it was mentioned that keten reacted with hydrocyanicacid, but that the product was not, as might have been anticipated,acetyl cyanide or pyruvonitrile.The reaction between keten and hydrocyanic acid has now beenfurther investigated, and a new compound, liquid at the ordinarytemperature, has been isolated in a pure state.The actual con-stitution of this compound has, however, not yet been elucidated ;but, as our collaboration has come to an end, and as t.he substancein question has somewhat remarkable properties, we venture toplace on record the results so far obtained.Analysis and molecular weight, the latter having been found bothby the vapour density and the cryoscopic methods, showed thesubstance to have the empirical formula C,H,O,N, its formationtaking place according to the equation:2CH2:C0 + HCN = C5H502N.The difficulty in the way of determining its constitution lies inits instability in presence of reagents.For, although it has aboiling point of 1 7 3 O , and its vapour does not dissociate a t thetemperature of boiling aniline, it behaves in all the reactionshitherto studied as if it were merely a mixture of keten and hydro-cyanic acid, were it not that the velocity of reaction is slower.Thus with water, eitber alone or in the presence of acids oralkalis, acetic and hydrocyanic acids are slowly formed :CYomlhatiorL~ withC5H,02N + 2H20 = 2CH,*C02H + HCN.* In the note referred to there is a misprint, the b.p. of the acetyl sulphideobtained being given as 55-58" instead of 155-158"DEAKIN AND WILSMORE : SONE REACTIONS OF RE'I'EN 1960Alcohol in presence of a trace of mineral acid acts in a similarway, giving ethyl acetate and hydrocyanic acid:C,H,02N + 2C2H5*OH = 2CH3*C02*CzH5 + HCN.With aniline a violent reaction takes place, acetanilide andhydrocyanic acid being produced :C5H502N + 2C,H5*NHz= 2CH3*CO*NH*C,H5 + RCN.Saturation of an ethereal solution of the substance with hydrogenchloride at a low temperature, followed by cautious addition ofwater, gave only ammonium chloride together with acetic and formicacids, and an attempt to reduce it by means of hydrogen in presenceof platinum black led to no definite result. Obviously therefore thesubstance is not a derivative of cyclobutan-1 : 3-dione.Although we ha.ve no very definite experimental evidence tooffer in support of it, still we may perhaps be allowed t o hazard aguess as to the constitution and mode of formation of the newcompound.We may suppose that hydrocyanic acid combines inthe first place with a, portion of the keten in a way similar to itsreaction with aldehydes and ketones to form a cyanohydrin, whichin this case would be the nitrile of the unstable a-hydroxyacrylicacid :CH,:CO + HCN = CH2:C(OH)*CN.As this nitrile contains a hydrox'jrl group, the latter would a tonce react with more keten to form the corresponding acetate:CH,:C(OH).CN + CH2:C0 = CR,:C(OAc).CN.It may be objected to this hypothesis that a-hydroxyacrylonitrilewould change, at least in part, into the well-known isomeric acetylcyanide or pyruvonitrile, which should accordingly be found amongthe products of the reaction.It may well be, however, that at thetemperature of the experiment this intramolecular change is com-paratively slow, whereas the reaction between keten and hydroxylis practically instantaneous. A second necessary condition is thatthe combination of hydrocyanic acid with keten shall be slow,otherwise, with excess of hydrocyanic acid present, there wouldbe no keten availab€e for the second stage of the process. Thatthis condition was fulfilled in our experiments was shown by thefact that a large part of the keten had time to polymerise tocyclobutan-l : 3-dione, although hydrocyanic acid was present inconsiderable excess. Following out the hypothesis, the decom-position with water may be supposed to proceed thus:CH,:C(CN)*O*CO*CH, + H20=CH2:C(OH)*0.CO*CH3 + HCN= (CH3*C0),O + HCN.(CH,*CO),O + H,O = 2CH3*C0,H1970 DEAKIN AND WlLSMORE : SOME REACTIONS OF KETEN.The reaction with aniline may take place as follows :CH, : c (CN) co CH3 + C6H5* NH,= CH,:C(CN)*OH + CH,*CO.NH*C,H,= CH,*C'O.CN + CH3*CO*NH*C,H,.CH3*CTO*CN + C6H5*NH2 = CH3-CO*NH*C6H, + HCN.The reaction with alcohol is less easy to follow, especially as itrequires the presence of mineral acid. It may be mentioned thatthe structure suggested is consistent with the molecular volume,refractivity, and dispersion of the substance.The actions of Grignard's reagent and of nitrosyl chloride onketen have also been studied. I n both cases the keten condensedfor the most part to brown, resinous substances, but from thereaction with Grignard's reagent a small quantity of acetone wasobtained, probably formed thus :CH,:CO -+ CH2:C(OMgT)*CK, -+ CH,:C(OH)*GH, -+CH,* CO*CH,.It was thought that nitrosyl chloride might give nit.rosoacety1chloride or the isomeric oximinoacetyl chloride, but the only sub-stance that could be isolated in a pure state wm chloroacetylchloride.EXPERIMENTAL.Prepa.ration of Keten and of the Hydrocyanic Acid Derivative.The pyrogenic method of preparing keten, previously describedby one of us (Trans., 1907, 91, 1938), has been somewhat improved.Spiral condensers provided with a cylindrical bulb a t the lowerezcl are now used in place of the simpler pattern previouslyillustrated, and it has been found advisable t o insert a secondtrap between the generator and the main condenser.Any ketenwhich condenses in the traps can be readily distilled over into themain condenser a t the end of the operation. The main condenseris kept at - l l O o to -120° by means of a bath of alcohol andether cooled by suitable addition of liquid air, which is not pouredinto the bath itself, but into a kind of flattened, metallic test-tubesuspended from the top of the Dewar vessel. A t a lower tem-perature the spiral of the condenser becomes rapidly blocked withcrystals, while at a higher temperature the condensation of theketen is incomplete, owing to its dilution with other gases. Aplatinum wire of about 0.2 mm. diameter and 5 cm.free lengthhas been found t'o give the best results. With a longer or thickerwire some keten will be carried away by the increased rush of gas,m the wire must be kept nearly at its melting point in any case. Acurrent of about 7 amperes is used to commence with, but this mustbe gradually raised to 12 or 14 amperes as the reaction proceedsDEAKIN AND WILSMORE : SOME REACTIONS OF KETEN. 1971as the wire becomes coated with a layer of conducting carbon.The acetic anhydride is added in charges of about 50 grams, aclean wire being used for each fresh charge. By carefully removingthe layer of carbon by crushing it with pliers, one wire may some-times be made to serve for three charges before breaking. Afterheating for about an hour and a-half, about half of the aceticanhydride will have disappeared, and the remainder will havebecome dark brown.The reaction is then stopped, the spent chargeis removed, a clean wire is inserted, and a fresh charge of aceticanhydride is poured in. Including subsidiary operations, three orfour such charges can be run through in a day, yielding altogether15 to 20 C.C. of crude keten. The acetic anhydride should be aspure as possible, or the yield will be much reduced; but inferiorsamples may be greatly improved in this respect by previouslydistilling from phosphoric oxide. Keten may also be preparedfrom acetone, but is then very impure. Strange to say, glacialacetic acid appears to be quite unacted on by the hot wire.To prepare the hydrocyanic acid derivative, 15 to 20 C.C.of ketenwere distilled into an exhausted bomb-tube cooled in liquid air.About twice this quantity of anhydrous hydrocyanic acid was added,and the tube was then sealed off before the blowpipe. The hydro-cyanic acid was prepared by the action of 50 per cent. sulphuric acidon potassium cyanide, and was dried by passing i t through a longcolumn of calcium chloride. It was stored in a bulb provided withtwo taps, from which it could be distilled into the bomb tubes asrequired. As there was an interval of only about loo betweenthe melting point of the hydrocyanic acid and the temperature atwhich the keten began rapidly to polymerise, arrangements had tobe made to keep the keten cold until the hydrocya.nic acid hadmelted, and then to mix the two liquids as rapidly as possible.Accordingly, on removing the bomb tube from the liquid air, thelower end containing the keten was well jacketed in wool, the upperpart containing the hydrocyanic acid being left exposed to the air,and the tube was placed in an inclined position in a shakingmachine and shaken for about two hours, or until it had attainedthe temperature of the room.It was then placed in an ice-safeuntil wanted. Since considerable pressure was necessarily developedin the tubes as the temperature rose, to minimise the effects of apossible explosion, the shaking and removal to the ice-safe wereattended to by one of us a t times when the laboratory was otherwiseunoccupied. The contents of the tubes were only slightly colouredbrown, showing that much less brown resin had been formed thanwhen keten polymerises in the ordinary way.Before opening, thetubes were again cooled to -78O, when, as t,he contents ha1972 DEBKLN AND WlLSMORE : SObIE REACTIONS OF KETEN.solidified, they could be opened with impunity, and they were thenremoved from the bath and allowed to attain the temperature ofthe room. As the contents showed the marked tendency to bumpcharacteristic of hydrocyanic acid, a capillary tube connected witha source of dry hydrogen was passed down to the bottom of thebomb-tube as soon as the contents were sufficiently melted. Withthe help of the current of hydrogen, most of the hydrocyanicacid was then distilled off, the tube being finally warmed to about50° in a water-bath.The contents of three such tubes were frac-tionally distilled under 100 mm. pressure, a Claisen flask beingemployed, to the second neck of which a Young’s ‘‘ pear ” still-headwith four bulbs had been sealed. The liquid separated mainly intotwo fractions, one boiling at about 70--80°, which was chiefly cyclo-butan-1: 3-dione, and the otEer boiling at 100-llOo, which con-tained the bulk of the new substance. Some brown residue wasleft in the flask, and crystals of dehydra.cetic acid, which wereidentified in the usual way, and which were due to the poly-merisation of cyclobutan-1: 3-dione, were deposited in the neck ofthe flask and lower portion of the still-head. After repeatedfractionation of the portion of higher boiling point, 7 grams of acolourless liquid were obtained, which boiled constantly at110*0-110~4°/100 mm.(corr.), this being the yield from about50 C.C. of crude keten. The fractionation was carried out in dryhydrogen. Carbon dioxide mas unsuitable for this purpose, as itwas very soluble in the liquid.Composition and Properties of the Hydrocyanic Acid Derivative.The carbon and hydrogen were determined by the method pre-viously used for acetylketen ” (Trans., 1908, 63, 947). Attemptsto estimate the nitrogen by the Kjeldahl method were unsuccessfulowing to loss of hydrocyanic acid, and a modification of the Dumasmethod was therefore emploxed. The substance was weighed inan exhausted thin-walled glass bulb, the weight of the air removedfrom the bulb (0.66 c.c.=0*8 milligram) being added to theapparent weight of the substance.The bulb was packed in copperoxide in the combustion tube, and, when all the air in the latterhad been swept out with carbon dioxide, i t was broken by meansof a pointed glass rod attached to the inlet tube. The vapourdensity was determined by the Hofmann method, using freshlydistilled aniline in the outer jacket, The volume observed wascorrected for the gas and vapour driven off from the walls of theendiometer, and, in measuring the pressure, allowance was madefor the temperature of the mercury column and for the vapourpressure of mercury at 184O, the boiling point of aniline under756.7 mm. pressure. The volume remained constant for abouDEAKIN AND WILPMORE : SOME REACTIOKS OF KETEN. 1978half an hour, showing that the vapour of the substance was stableat the temperature of boiling aniline.The benzene used in deter-mining the molecular weight by the cryoscopic method had beer,previously distilled from sodium :0.1705 gave 0.3393 CO, and 0.0672 H20.0.19990.08590.0882, in 16-93 benzene, gave A t = - 0'260O.C=54.2; H=4*4.0.1369 ,, 0.2702 CO, ,, 0.0580 H20. Cz53.8; H=4.7.,, 21.7 C.C. N, (dry) at 14.8O and 755.1 mm.,, 58.6 C.C. at 184O and 375.9 mm.N=12.8.M.W. =111.2.M.W. = 100.2.0.0697, ,, 16.93 ,, ,, A t = - 0.186O. M.W. = 110.8.0.1157, ,, 16.93 ,, ,, A t = - 0.298'. M.W. = 114.8.C,H,O,N requires C = 54.1 ; H = 4.5 ; N = 12.6 per cent.M.W. = 111.04.Under 772 mm. pressure, the liquid boiled at 173O (corr.), butit began t o turn brown a little below that temperature.Oncooling, a white opalescence appeared at about -45O, which dis-appeared again on warming to -42O, but this must have been dueto a trace of moisture or other impurity, as the substance remainedliquid, although it became very viscous, down to -78O. On coolingwith liquid air, it froze to a white solid, which melted at -196'to -195O. Owing t o the presence of the opalescence, the meltingpoint could not be found by visual observation, but it was readilydetermined by means of a thin wire, moisture being excludedby jacketing the wire with calcium chloride in the upper part ofthe tube. On repeated trials, the wire was found to be immovableup to -196O, but it could be moved up and down at - 195O.The density was aetermined at various temperatures.Twosamples of the substance were used, the first of which had beendistilled some weeks, and the second a few days before $he experi-ment. The densities in each series lie very nearly on it straightline, but there is a difference of about five parts in 10,000 betweenthe two series. As a mean of four weighings, the pyknometercontained 0.74325 gram of water weighed in air at 18O. Thetemperatures in the table have been corrected to the hydrogenscale :t.0 -3O10'013.914.216.618.521 '322'924.829.930 '3Weight of substance iii air. T I.0.7S970.79600 '79370-79010-78700.78260.79950.79610.79250.78890.78334&. - I.I I.1'07461 *0743l'C6951.06971'06641.06471'06141.05981.05711'05213'0611974 DEAKIN AND WILSMORE : SOME REACTIONS OF KETEN.Taking the mean of the two series by graphic interpolation, thedensity of the liquid between loo and 30° is given by the equation :46t = 1.0685 - 0.001 12 (t - 15').Consequently, assuming ths molecular weight to be 111.04, themolecular volume at 1 5 O is 103.9, whereas the molecular volumecalculated for the formula CH,:C(CN)*O*CO*CH, from Traube'svalues for the atomic volumes (Traube, Grundriss der pi~ysikalischenChemie, 1904, p. 120 ; Smiles, Chemical Constitution and PhysicalProperties, 1910, p. 125) is 100-2.The refractive indices of the same two samples were measuredby means of the Pulfrich refractometer.The densities wereobtained by interpolation from the values given above, the twoseries being kept separate :Line. Sample. t. 4% AT. M. R.C, I. 16'9" 1.0667 1'42443 26.580C. 11. 22'6 1'0598 1.42150 26-598D. I. 16'0 1.0676 1.42771 26.734D. 11. 23 '1 1 *0592 1.42435 26.771G'. 11. 22 -5 1.0599 1.43756 27-478Taking the mean of the two series, and using the values for theatomic refractivities and dispersions given in Landolt andBornstein's '' Tabellen," we obtain the following values for themolecular refractivity and dispersion :C D at- cFound ... 26-59 26.75 0'89Calculated for CH,:CiCN)*O*CO*CH; 26-34 26-49 0.79At the ordinary temperature the hydrocyanic derivative is acolourless, somewhat oily liquid. It has a rather pleasant, althoughslightly pungent odour, resembling that of the nitriles.It isreadily miscible with all the ordinary organic solvents, but issparingly soluble in cold water. It is more readily soluble in hotwater, separating again as an emulsion on cooling. It is, however,slowly decomposed and dissolved by water on keeping, even in thecold, acetic and hydrocyanic acids being formed, and this whetherthe aqueous solution was originally neutral, acid or alkaline; buton warming it with aqueous alkalis or sodium carbonate, somebrown substance is also formed. This hydrolysis has been studiedquantitatively in both acid and neutral solution. Since methyl-orange cannot be used as an indicator for acetic acid, and phenol-phthalein is useless in presence of soluble cyanides, the followingmethod of titration was adopted. Standard alkali free fromcarbonate was first added in slight excess, that is, in the proportionof rather more than three equivalents of alkali t o one moleculeof the substance, and the cyanide wits titrated with standard silveDEAKIN AND WILSMORE : SOME REACTIONS OF BETEN.1975nitrate, the end-point being shown, as usual, by the formation of apermanent opalescence. A second equal volume of silver solutionwas then added, in order to replace all the CN' in solution byNO,', after which the excess of alkali could be found by meansof standard acid and phenolphthalein. Proceeding in this way,the alkali used corresponded with the hydrocyanic as well as withthe acetic acid, so that, t o find the amount of t.he latter, the hydro-cyanic acid as found from the silver titration had to be subtractedfrom the total acid.To carry out the hydrolysis in acid solution,a weighed amount of the substance was placed in a stoppered flask,together with 50 C.C. of water and 1 C.C. of 0-1092N-sulphuric acid.The mixture was kept overnight, warmed for a few minutes on thewater-bath, cooled, and titrated, the sulphuric acid being allowedfor.0.3041 required 13.33 C.C. silver and 76-91 C.C. alkali; or 1 mol.gave 0.973 mol. HCN and 1.988 mol. C,H,O,0.2943 required 12-90 C.C. silver and 72-69 C.C. alkali; or 1 mol.gave 0.975 mol. IECN and 1-919 mol. C2H402.For the hydrolysis in alkaline solution, the substance was addedat once to excess of the standard alkali.After about two hours atthe ordinary temperature, the reaction appeared to be complete,and the solution was titrated :0.2820 required 12.16 C.C. silver and 70.85 C.C. alkali; or 1 mol.gave 0.967 mol. HCN and 1.975 mol. C,H402.0.3142 required 13.86 C.C. silver and 80.80 C.C. alkali; or 1 mol.gave 0.979 mol. HCN and 2.032 mol. C2H402.The reaction is thus not quite quantitative, but i t is sufficientlyso to prove the validity of the equation given on p. 1968.An attempt was next made to hydrolyse the CN group withoutbreaking up the molecule. 2.33 Grams of the compound weredissolved in about 20 C.C. of dry ether; the solution was cooled to-78O, and dry hydrogen chloride was passed in until two layersbegan to separate, the lower one being a solution of ether in liquidhydrogen chloride.Two molecular proportions of water, dissolvedin 20 C.C. of ether and cooled to -78O, were then added, and themixture was kept overnight, the temperature gradually rising toabout Oo. As no reaction appeared to have taken place, even onwarming to the boiling point of ether, a third molecular proportionof water was added, and ether was evaporated until water beganto separate. On again keeping overnight at the ordinary tem-perature, ammonium chloride crystallised out, and the solution wasthen fractionally distilled. After the ether had been expelled, afraction passed over at 85--103O, which gave all the reactions offormic acid. A second fraction, which passed over at 103-135O,The silver nitrate was 0*1N, and the alkali 0.1055N 1976 DEAKIN AND WILYMORE : SOME REACTIONS OF KETEN.was also acid.It was redistilled from concentrated sulphuric acidto destroy any formic acid, and it then answered to the tests foracetic acid. A small quantity of liquid which still remained inthe flask was heated under a pressure of 35 mm. to 230°, but i tmerely charred without distilling. The hydrolysis of the hydro-cyanic acid derivative had therefore followed practically the samecourse as in aqueous solution.The substance did not appear to react with absolute alcohol, buton adding dry hydrogen chloride the odour of ethyl acetate wasnoticed. On treating another portion of the alcoholic solutionwith lime, a vigorous reaction took place, hydrocya.nic acid andethyl acetate being given off.To a larger portion of the solutiona small quantity of ethylsulphuric acid was added, and the mixturewas left for two days, when hydrocyanic acid and ethyl acetatewere again noticeable. On passing a current of dry air throughthe solution and then into water, hydrocyanic acid was readilyidentified in the latter. The alcoholic solution was then boiled forsome time over phosphoric oxide in a flask fitted with a refluxcondenser, and finally distilled, when, after all the hydrocyanic acidhad been driven off, a sample of ethyl acetate was obtained, whichboiled steadily at 7 7 O (corr.).The compound reacted vigorously with aniline, hydrocyanic acidbeing given off, and a solid substance being formed, which proved tobe acetanilide, melting at 1 1 3 O (corr.).This was confirmed bytaking a mixed melting point with a sample of pure acetanilide fromother sources. The reaction appeared to be quantitative.Action of Grignctrd’s Reagent on Keten.The reagent (magnesium methyl iodide) in dilute ethereal solutionwils cooled to -50°, and gaseous keten was slowly passed in. Avery vigorous reaction took place, and much heat was evolved, aswas shown by the amount of solid carbon dioxide which wits requiredto maintain the low temperature. As only resinous substancesappeared to be formed, the experiment was repeated, but this timethe keten was largely diluted with dry hydrogen, the dilutionbeing effected by passing the hydrogen through liquid keten at-78O to -7OO.The ethereal solution became dark reddish-brownand very viscous, and a yellow, resinous solid separated. Themixture wits decomposed with powdered ice, and the magnesiumhydroxide was dissolved by addition of dilute hydrochloric acid,leaving a considerable amount of brown resin, which was not solublein either the water or the ether. This was removed by filtration,and the filtrate wa.s fractionally distilled. After the ether hadbeen removed, st small quantity of liquid passed over at abouDEAKIN AKD WILSMORE: SOME REACTIONS OF KETEN. 1977looo, which had a strong odour of acetone The presence of acetonewas confirmed by the iodoform reaction, by the alkaline mercuricchloride and nitroprusside tests, and by the formation with benz-aldehyde of distyryl ketone (m.p. 111-112°, corr.). No othercompound could be isolated.Action of Nitrosyl Chloride on Keten.The nitrosyl chloride was prepared by passing nitric oxide intoliquid chlorine at about -60° until saturated. The chlorine wasobtained from hydrochloric acid and potassium permanganate. Itwas washed with water and dried with sulphuric acid. The nitricoxide was produced by the action of nitric acid on copper, and waspurified by passing first through 50 per cent. potassium hydroxidesolution and then through concentrated sulphuric acid. Thenitrosyl chloride was fractionally distilled before use to remove anyexcess of chlorine.A t first, attempts were made to carry out the reaction by con-densing the keten with excess of nitrosyl chloride in bomb-tubes bymeans of liquid air, and allowing the temperature gradually to rise,but violent explosions took place as soon as the nitrosyl chloridemelted.Accordingly, another method was tried, gaseous keten beingpassed slowly into excess of nitrosyl chloride at a temperature justabove the melting point of the latter (-61O). Vigorous reactiontook place at once, with evolution of much heat, hydrogen chlorideand an odour of carbonyl chloride being given off, and a whitesolid separating out, which melted at about -5OO. I f the tem-perature was allowed to rise during the reaction, much gas wasevolved, which, on analysis, proved to be a mixture of hydrogenchloride, carbonyl chloride, carbon dioxide, acetylene, and nitrogen.The acetylene and some or all of the carbon dioxide were impuritiesin the original keten. Afterall the keten had been added, the temperature was allowed to rise,and a current of hydrogen was passed through the mixture in orderto remove the excess of nitrosyl chloride, when a dark brown, veryviscous liquid was left. On distilling this under a pressure of 95to 100 mm., a colourless liquid passed over at 58-68O. This liquiddid not contain nitrogen. Under atmospheric pressure it boiled at106O. It reacted with water to form chloroacetic acid, and withaniline it gave chloroacetanilide, melting at 1 3 3 O , which was con-firmed by taking a mixed melting point with a sample of chloro-acetanilide from another source. The colourless liquid was thereforechloroacetyl chloride, in the formation of which the nitrosyl chloridehad apparently acted merely as a source of chlorine. A largequantity of a brown, resinous substance was left in the distillingThe gas did not contain nitric oxide.vor,. XCVII. G 1978 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN.flask. This was found to contain nitrogen, but a definite com-pound could not be obtained from it. Attempts to obtain il cleanreaction by previously diluting the nitrosyl chloride with dry ethermet with no better success.U N I V E R S I T T COLLEGE,UNIVERSITY OF LONDON

ISSN:0368-1645    

DOI:10.1039/CT9109701968

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

1978 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN.CCX.-The PoZymerisatiorz o f Keten. cycloButan- 1. : 3-dione (" Acetylketen ' I ) .By FRANCES CHICK and NORMAN THOMAS MORTIMER WILSMORE.IN a previous paper (Trans., 1908, 93, 946) we stated that whenketen, either in the liquid or the gaseous state, is left to itself atthe ordinary temperature, a brown substance is formed, the chiefconstituent of which is a colourless liquid of a very pungent odour,boiling at 126--127O/760 mm. (corr.), and which, after havingbeen frozen, melts at - 7 O to -6O; and we showed by combustionana.lyses, by determination of the vapour density according to theHofmann method, and by measurement of the freezing point ofits solution in benzene, that this liquid is a polymeride of keten,formed according to the equation 2CH2:C0 = C4H402 We alsoshowed that the substance undergoes a series of reactions whichindicate a close relation with acetoacetic acid.Thus, with waterin the cold, acetoacetic acid itself is produced:on boiling with alkalis, acetates are formed:C4H402 + Ba(OH), = Ba(C,H30,)2 ;with aniline, a very vigorous reaction takes place, resulting in theformation of acetoacetanilide :C4Hd0, + C6H5*NH2 = CH3*CO*CH2*CO*NH*C6H5 ;and with phenylhydrazine, a phenylhydrazone-phenylhydrazide ofacetoacetic acid is obtained :C4H40, + 2C6H5*N,H3 =C4H402 + HzO = CH3*C0CH2*@O2H ;CH,*C(:N*NHPh)-CH,*CO*NH*NHPh + R,O.The hydrazide character of the latter substance was shown bythe formation of a hydrochloride and of a platinichloride.Additionof pyridine to the polymeride caused a violent reaction, with theformation of brown resins; but when the reaction was allowed totake place in benzene solution, dehydracetic acid w i ~ s the chiefproduct.All these facts led us to conclude that the polymeride stilCHICK AND WILSMORE : THE POLYMERISATION OF KETEN. 1979contained a keten group, and we therefore assumed it to be acet-yl-keten, having the formula CH,*CO*CH:CO. A t the same time, weconsidered the possibility of its being cyclobutan-1 : 3-dione :as this would agree better with our observation that it did notappear to react with alcohol. Nevertheless, the great reactivityand very unsaturated nature of the substance led us to prefer theketen formula, and a measurement of the refractive index alsoseemed to support this choice:M.R.CH,*CO*CH:OO .................. 29.489CH,/ \CH, ..................... 18,782CH~C(oH))CIH .................. 20.664Found ................................. 20 -075co\co/\C(OH)/Here, however, we had to suppose that the *CH:CO group hada depressing action on the refractive index, an assumption which,on account of lack of experimental evidence, we made with allreserve.After the publication of the previous paper, the work was for atime interrupted, and it was not until the session just closed thati t could be seriously resumed. I n the meantime a paper byStaudinger and Bereza has appeared (Bey., 1909, 42, 4908), inwhich the polymerisation of the disubstituted keten, ethyl ethyl-ketencarboxylate, CO:CEt*CO,Et, is described, the productaccording to these authors being undoubtedly a cyclobutanederivative, namely, ethyl 1 : 3-diethylcyclobutan-2 : 4-dione-1 : 3-di-car b oxylat e,CO,Et*CEt<Eg>C Et-CO,Et,and on this and other grounds they conclude that the substancediscovered by us must be A1-cycZobuten-l-ol-3-one,The arguments of Staudinger and Bereza did not, however, seemto us to be necessarily convincing.Thus, ethyl 1 : 3-diethylcyclo-butan-2 : 4-dione-l : 3-dicarboxylate reacts with two molecular pro-portions of aniline to form two molecules of ethyl ethylmalonanilate :C0,Et*CEt<CO>CEt*C02E:t co + ZC,H,*NH, =2C02Et-CH Et*CO-N H*C,H,.Also, on heating, the diethyl ester dissociates with regeneration6 0 1980 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN,of ethyl ethylketencarboxylate. Our substance, on the other hand,reacts with only one molecular proportion of aniline, and it showsno tendency to dissociate on heating-quite the contrary.Similarremarks apply also to the reactions of truxilic acid referred to byStaudinger and Bereza in this ccnnexion. Again, the comparativestability of the polymeride of keten, both in the pure state andin alcoholic solution, which Staudinger and Bereza cite as beinginconsistent with the keten formula, was not conclusive, moreespecially as our previous observations on these points were incom-plete. We have since found that alcohol reacts with the polymerideif a trace of mineral acid be present, forming acetoacetic ester:C4H402 + C,H,*OH = CH3*CO*CH,*C0,-C2H, ;and that, when the pure substance is kept for some weeks in sealedtubes at the ordinary temperature, dehydracetic acid is formed,apparently by direct polymerisation.Moreover, Staudinger andBereza show that disubstituted ketens become much less reactivewhen one of the substituents is an acidic group, and, conseguently,it was not unreasonable to assume, as we did, that the substitutionof acetyl for a hydrogen atom in keten should have a similar effect.So far therefore there was not sufficient evidence available toallow of a definite conclusion being drawn between the open chainand the cyclic formula for the first polymeride of keten. Most ofthe reactions described above involved a transference of a hydrogenatom from the reagent t o the polymeride, and there was nothingto show into which part of the molecule of the latter this atomhad entered.It occurred t o us that a study of the action of bromine on thepolymeride might throw some light on its constitution.We foundthat bromine combined directly with the substance, forming amonobromoacetoacetyl bromide, which, on treatment with alcohol,gave the corresponding ethyl monobromoacetoacetate. If thepolymeride had the acetylketen structure, addition of bromineshould give the a-bromoacetoacetyl bromide :CH,*COCH:CO + Br, = CIH,*CO*C'HBr*COBr,whereas from cyclobutan-1 : 3-dione only the y-derivative couldresult :Since we have actually obtained the y- and not the a-derivativeunder conditions which rendered a wandering of the bromine atomfrom the a- to the y-position highly improbable, it follows that theevidence in favour of the cyclic structure for the first polymerideof keten is now conclusive.It may be noted, however, in passing,that the substance may still be regarded as an internal anhydridCHICK AND WILSMORE : THE POLYMERISATION OF KETEN. 1981of acetoacetic acid. The true acetylketen has therefore yet to bediscovered, but we venture to prophesy that, when prepared, it willresemble cyclobutan-1 : 3-dione in many of its reactions.Incidentally, by treating the above-mentioned y-bromoacebacetyl bromide with aniline, we have obtained the same bromoaceto-acetanilide as was prepared by Knorr (Annulen, 1886, 236, 79) bythe bromination of acetoacetanilide, and, by digesting this withconcentrated sulphuric acid as described by him, we also obtainedhis bronio-2-hydroxy-4-methylquinoline (Zoc.cit., p. 91). Knorr alsoprepared a substance, which he believed to be identical with thelatter compound, by the action of bromine water on Z-hydroxy-4-methylquinoline itself. As under these conditions the brominewould almost certainly occupy the 3-position, Knorr assumed thathis bromoacetoacetanilide was the a-derivative, the condensationwith sulphuric acid taking place according to the equation:Me60 Me,/'We now find, however, that the compound formed on brominating2-hydroxy-4-methylquinoline is not identical with, but is an isomerideof, the bromo-2-hydroxy-4-methylquinoline produced by the actionof sulphuric acid on bromoacetoacetanilide ; and, since our synthesisshows that the latter substance undoubtedly has the bromine inthe y-position, it follows that the compound obtained from it bythe action of sulphuric acid is o-bromo-2-hydroxy-4-methylquinoline :CH,BrCH The semi-enclic formula, CO<cG>C*OI-I, proposed by Stsudingerand Bereza agrees better than the diketonic foimula, CO<Ez2>CO,with the molecular volume, refractive index, and dispersion of thesubstance, as we shall show later; but we can find no chemicalevidence for it.cycZoButan-1: 3-dione does not appear to reactwith sodium, with acetyl chloride, or with phenylcarbimide. I nfact, a mixture of it with phenylcarbimide may be separated intoits constituents by fractiona.1 dist,illation.It may be mentioned,however, in this connexion that the substance gives a red colourwith ferric chloride in alcobolic solution. The semi-enolic formula,1982 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN.is also inconsistent with the reaction with phenylhydrazine, thissubstance reacting normally with B-diketones, which can exist in thesemi-enolic form to form a pyrazole ring. The reaction with phenyl-hydrazine is supported by that with semicarbazide, two molecularproportions of which react with cyclobutan-1: 3-dione to form asemicarbazone-semicarbazide of acetoacetic acid :CH2<CO>CH, co + BCO*N,H, =H,O + CH,*C(:N*NH*CO*NH,)*CH2*CO*NH*NH*CO*NH2.Dry ammonia combines with cyclobutan-1 : 3-dione at low tem-peratures to form acetoacetamide, previously prepared by Claisenand Meyer (Ber., 1902, 35, 583) by the prolonged action of diluteaqueous ammonia on acetoacetic ester :CH,<~~>CH, UO + N H ~ = CH,*CO*CH,*CO=NH~.By the further action of dry ammonia, acetoacetamide is convertedinto a yellow oil.This oil could not be purified, but it appearedto consist mainly of the hitherto non-isolated amide of P-amino-crotonic acid, CH,*C(NH,):CH=CO*NH,, for, on heating it in acurrent of dry hydrogen, a crystalline substance was produced,melting a t 197O, and having the empirical formula C,H,,O,N,.From analogy to the condensation of acetoacetamide described byClaisen and Meyer, this crystalline substance is probably 4-amino-2 : 4 - dimethyl - A2 - tetrahydro-6-pyridone-3-carboxyZamide, formedthus :NH, CH, NH, CH,\/C\/CFrom its reactions the stability of the cyclobutan-1 : 3-dione ringis thus seen t o be very small, even when compared with that ofcyclobutane prepared by Willstatter and Bruce (Ber., 1907, 40,3979).I n fact, the substance behaves as if the ring were notcompletely closed, that is to say, as if its constitution were:QH2* GO-CO*CH,-Since, however, there is no precedent for such a formula as this,we are not prepared seriously to propose it.The action of Grignard’s reagent (in this cam magnesium methyliodide) gave for the most part only by-products which could not bCHICK AND WILSMORE THE POLYMERISATION OF KETEN.1983identified, but there was some indication of the formation ofdiacetone alcohol, which was probably produced somewhat asfollows :Reduction of cy clobutan-1 : 3-dione with hydrogen in the presenceof platinum black gave an unlooked-for result, n-butyraldehydebeing formed, The reaction may possibly take place in the followingstages :or C,H,O, + 6H = CH,-CH,*C~*CHO + H,O.As the intermediate compounds have not been isolated, it is notpossible to say exactly at what stage the ring is broken. Theelimination of water would be facilitated by the dehydrating actionof unchanged cydobutan-1 : 3-dione.The further polymerisation of cyclobutan-1 : 3-dione to de-hydracetic acid may perhaps be represented by the followingscheme, although many others are possible, especially if cydobutan-1 : 3-dione be given the open-chain structure suggested above:(JH.. . . . . . . . -. -. . . .CO<~,H;>C:C<~~>CH, + H,O = C O < ~ ~ ~ \ CJ33 c(oH):c<~~>cH,= CH,. CO~CH,~ cq0- CH*CO C O > ~ ~ z .Collie’s formula for dehydracetic acid (Trans., 1891, 59, 179)has here been chosen. The condensation would be much moredifficult to follow if dehydracetic acid had the formula assigned toit by Feist (Annalen, 1890, 257, 253).Much work has been done with a view to discovering the con-stitution of the yellow substance which is formed from cyclobutan-1: 3-dione in the presence of quinoline; but, on account of thesmall quantity available, not much success has been obt~ained.I n our former paper we stated that “acetylketen” combinedwith sodium ethoxide in dry alcohol to form sodium ethylaceto-acetate, which, on boiling with hydrochloric acid, gave carbondioxide and methyl propyl ketone.Since the polymeride of ketenis in reality qczobutan-1: 3-dione, the compound formed withsodium ethoxide must have been sodium butyrylacetate, which1984 CHICK AND WIISMORE : THE POLYMERISATION OF KETEN.however, would also give methyl propyl ketone on boiling withhydrochloric acid :CH2<E>CH, + Na0*C2H5 = CH,*CH,*CH,*CO*CH,*CO,NaCH,~CH,*CH,*CO*CH,*CO,Na + HCI =NaCl + CO, + CH,*CH,*CH,*CO*CH,.We propose to study this type of reaction more fully.cgcZoButan-1: 3-dione does not react with hydrocyanic acid, evenwhen the two substances are heated on the water-bath in sealedtubes, and it does not react with liquid cyanogen at the ordinarytemperature.EXPERIMENTAL.Preparatbn of cycloButan-1: 3-dione.We have not succeeded greatly in improving the yield of cyclo-butan-1 : 3-dione, about 5 grams from 150 grams of acetic anhydridebeing the best hitherto obtainable.It is not necessary to frac-tionate the crude keten, beyond allowing the temperature to riseto about - 80° to - 70°, before distilling it into the pressure tubes.There seems to be little risk of explosion if the tubes are carefullymade, and they may be handled with safety after polymerisationhas taken pIace, as the internal pressure will then have diminished.They should, however, be re-cooled to about -8OO before beingopened, or loss of substance may be caused by the rush of gas.Diluting the keten with ether to diminish the violence of the poly-merisation did not noticeably improve the yield; but, on the otherhand, surrounding the tube containing the keten with a bath ofalcohol cooled to -30°, or lower, and allowing the whole slowlyto attain the temperature of the room, materially reduced theformation of brown resins.To ensure complete polymerisation, thetubes should be kept for st day or two before being opened. Thedistillation of the cyclobutan-1 : 3-dione is conveniently carried outunder about 30 mm. pressure, when the bulk of the substance passesover as the temperature of the bath rises from 40° to 60°. Thetemperature should, however, finally be raised to about looo.Theliquid then remaining in the distilling flask consists of dehydraceticacid and brown resins. The distilling flask should be heated by awater- or oil-bath, and not by a naked flame, or the distillatemay be contaminated with decomposition products from the residue.The whole apparatus should, of course, be carefully dried and filledwith dried air before commencing the distillation; and only driedair should be allowed to enter the apparatus during and at theclose of the operation. These precautions are especially necessarywhen it is intended to study the physical properties of the subCHICK AND WILSMORE : THE POLYMERISATION OF ICETEN. 19S5stance. The preparation of cyclobutan-1 : 3-dione may be recom-mended as a useful exercise for students in laboratories where asupply of liquid air is available.Physical Properties of cycloButan-1: 3-dione.We have confirmed the boiling point of cyclobutan-1: 3-dioiicunder 760 mm.pressure previously given. Under 100 mm. pressurethe substance boils at 69-71O (corr.). The freezing point of a,carefully prepared sample was found t o be -7.9O t30 -7.5O.The density of two samples of the substance was determined atvarious temperatures. As a mean of four weighings (0.7432, 0.7433,0.7432, 0.7433), the pyknometer contained 0.74325 gram of waterweighed in air at lao. The weights of cyclobutan-1: 3-dione andthe densities calculated from these were as follows:t.9 -5"10.514.114'317 718.721'622.725 '326.729.3Weight of substance in air.I.11.e-0.82380.82260.81960.81930.81 650.81570.61300'81230-80980.80880'806446t. r. 11. v 1'10531.10081'09691.09211,08771.08301.10121.09581.09121.0864The temperatures were measured by means of a thermometerwhich had been carefully compared with a standard thermometerfrom the International Bureau of Weights and Measures, and theyhave been corrected to the hydrogen scale. The densities in eachseries lie very nearly on it straight line, but there is a difference offrom 2 to 4 parts in 10,000 between the two series. The densityat 2 3 O , given in our previous paper, is in line with those in thefirst series. Taking the mean of the two series by graphic inter-polation, the density of cyclobutan-1 : 3-dione between loo and 30°is given by the equation :*& = 1.3 000 - 0.001 18(t - 15').Taking the molecular weight its 84.03, the molecular volume at15O is 76.39.Assuming Traube's values for the atomic volumes at15O (Traube, Grulzdriss d e r physikalischerc Chemie, 1904, p. 120;Smiles, Chemical Constitution and Physical Properties, 1910, p.125) : C = 9.9 ; H = 3.1 ; Oco = 5.5; OOH = 2.3 ; ring formation = - 8.11986 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN.and molecular co-volume = 25.9, we obtain the following calculatedvalues :CH,*Cd.CHCO ........................ 88.9Found.. .................................. 76 -4This property is therefore decisively in favour of a cyclic formula.The enolic formulz appear to agree better than the diketonicformula, but it is quite possible that the contraction due to theformation of the cyclobutane ring is more than 8.1 units, thisnumber having been obtained mainly from a study of benzenoidsubstances.*The refractive index of cyclobutan-1: 3-dione has been re-determined, using portions of the two samples just mentioned, withthe result that the value for the D line given in our former paperwould seem to have been too low. This may have been due to theprecautions to exclude moisture having been insufficient. Thedensities were interpolated from the values given above :First Sample.Line. t . N. 46t. M. R.C 18.7" 1'43490 1.0957 20'007D, 19'2 1'43?69 1.0951 20,131G' 18.7 1.45179 1.0957 20'680Se5cond Sampie.C 18'6" 1 -43547 1.0958 20-02918-3 1.43877 1.0961 20'15718.7 1.45236 1.0957 20.702D, G'Both sets of numbers give as the value for the molecular'' dispersion," 0.673.For Comparison, the values for the molecularrefractivities and dispersion, calculated from the atomic refrac-tivities given in Landolt and Bornstein's '' Tabellem " for thevarious isomeric formulR, will be found in the table herewith :CH;CO'CH:COFound.. ..........C. Dl G' - C'.18-53 18.78 0.4719-54 19.72 0-6420-56 20'66 0.8020.36 20'49 0.7020.02 20'14 0.6CHICK AND WILSMORE : THE POLYMERISATION OF KETEN. 1987From these figures it would appear that of the possible ringformulze the semi-enolic modification is the most probable. Thevery unsaturated nature of the substance, however, makes itlegitimate to amume the existence of an exaltation of the refractiveindex and dispersion which would raise the values calculated forthe diketonic formula by an amount rather Iess than that due to adouble bond.The study of the absorption spectrum has been kindly repeatedfor us by Professor E.C. C . Baly, using various thicknesses of a0.1 molar solution in dry ether. The result was to confirm theobservation of Mr. H. E. Watson given in our former paper.There was no selective absorption, and only it slight generalabsorption in the ultravioletAntalysis of cycloButan-1: 3-dione.- -As a further check on thecomposition, it third analysis of the substance was made:0-1298 gave 0.2704 CO, and 0.0599 H,O.C4H,0, requires C=57.1; H=4.8 per cent.Action of Alcohol on cycloButan-1: S-dione.-As stated earlierin the paper, cyclobutan-1 : 3-dione combines with ethyl alcohol inthe presence of a trace of mineral acid.To about 0.5 gram of thecompound dissolved in ethyl alcohol, a small quantity of a dilutealcoholic solution of sulphuric acid (ethylsulphuric acid) was added.After two days the odour of cyclobutan-1 : 3-dione had disappeared.The free acid was neutralised by shaking with moist calciumcarbonate, and the mixture was dried with calcium chloride, filtered,and distilled-towards the end under diminished pressure. The lastfraction had the odour of acetoacetic ester, gave the characteristicviolet colour with aqueous ferric chloride, and boiled a t 1 8 2 O /760 mm.(corr.), pure acetoacetic ester boiling at 1819C=56.8; H=5.1.,4 ction of Bromine on cycIoButnn-1: 3-dione : y-BrornoacetoacetylBromide.In order to study the action of bromine on cyclobutan-1 : 3-dione,these substances were diluted with carbon tetrachloride, which hadbeen dried over calcium chloride and distilled. The bromine waspurified by washing with aqueous potassium bromide and thenwith water, and distilling from phosphoric oxide. In a preliminaryexperiment a, dilute solution of cyelobutan-1 : 3-dione was titratedwith a bromine solution, using the colour of the bromine asindicator. The strength of the bromine solution was found inthe usual way by shaking with aqueous potassium iodide andtitrating with thiosulphate.The titrstion of the cyclobutan-1 : 3-dione was not very sharp, as towards the end the reaction becamevery sIow, but it WAS sufficient to show that the substances reacte1988 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN.in molecular proportions. 0.384 Gram of cyctobutan-I : 3-dionerequired 0.707 gram of bromine, whilst according to the equationC,H,O, + Br, = C4H4O2Br2, 0.732 gram should have been used. Tocarry out the bromination on a larger scale, cyclobutan-1 : 3-dione,in weighed quantities of from 2 to 5 grams, was dissolved in about50 C.C. of carbon tetrachloride contained in a 100 C.C. measuringflask. An equivalent amount of bromine, dissolved in 20 to 30 C.C.of carbon tetrachloride, was then run in very slowly from a burette,the flask meanwhile being kept immersed in cold water and wellshaken.The reaction appeared to be over when a little more than95 per cent. of the bromine had been added. The solution of theacid bromide fumed strongly on contact with moist air, and reactedvigorously with water, giving hydrobromic acid. To prepare theester, alcohol, which had been dehydrated by means of metalliccalcium, was added to the solution of the acid bromide. Thesubstances reacted at once with evolution of heat, and the hydrogenbromide which was formed, being much less soluble in carbontetrachloride than in the ester, '' salted out " the latter, whichformed a light brown layer on top of the tetrachloride. We havefound that the same thing occurs if carbon disulphide is used assolvent in place of the tetrachloride. This phenomenon must, havebeen observed in brominating ethyl acetoacetate in the ordinaryway, but we have not seen it mentioned.On shaking the mixturewith water, the ester at once dissolved in the carbon tetrachloride.The washing with water was continued until all free acid had beenremoved. The solution was then dried over calcium chloride, thecarbon tetrachloride and any alcohol remaining were evaporated,and the residue was distilled under 10 mm. pressure, the bulk ofthe ester passing over between l l O o and 115O. This is about 1 5 Olower than the boiling point of the y-bromoacetoacetic ester under10 mm. pressure given by Epprecht (AnnuZen, 1894, 278, 77);but, as this author does not state that the mercury in his manometerhad been properly boiled out, the pressure in his apparatus wasprobably rather higher. The presence of bromine in the eiter wasproved by warming with dilute sodium hydroxide, sodium bromidebeing formed.With copper sulphate and sodium acetate, a brightgreen copper salt was produced. The y-position of the. bromine inthe ester was also shown by the reaction with thiocarbamide, asdescribed by Epprecht (Zoc. c i t . ) , ethyl 2-aminothiazolyl-4-acetate,melting at 93-94O, being obtained according to the equation:CH,Br*CO-CH,*CO,Et + CS(NH,), CHICK AND WILSMORE : THE POLYMERISATION OF KETEN. 1989Ethyl a-bromoacetoacetate would have given with thiocarba.mide,ethyl 2-amino-4-methylthiazole-5-carboxylate, melting at 175O :It is well known, however, that in certain circumstances thea-bromo-ester may be converted into the y-bromo-ester by the actionof hydrogen bromide, and it occurred to us that this might possiblyhave taken place when the alcohol was added to the acid bromide.The “salting out” of the ester by the hydrogen bromide wouldcertainly facilitate such an interchange.Accordingly, the synthesisof the ester was repeated in a slightly different way. The solutionof the acid bromide was run very slowly into excess of alcohol, inwhich finely ground, dry sodium acetate was suspended, the mixturebeing kept well stirred during the process. The bromination ofthe cyclobutan-1 : 3-dione and the reaction with alcohol were bothcarried out a t Oo. This time no “salting o u t ” of the ester tookplace.The solution was washed with water, dried, and concentratedM before, but the ester was distilled under 5 mm. pressure, andpassed over below looo, leaving only a very small residue in thedistilling flask. The yield of ester was about 75 per cent. of thatcalculated from the weight of cyclobutan-1 : 3-dione taken. Theester thus obtained was quite colourless. The thia.zole derivativewas also very nearly colourless, but it melted as before at 9 3 O(corr.), even after repeated recrystallisation from ether.To prepare y-bromoacetoacetanilide, a little less than onemolecular proportion of aniline dissolved in carbon tetrachloridewas added slowly to a solution of y-bromoacetoacetyl bromide inthe sa.me solvent.The anilide separated at once in the form ofan almost white precipitate, which, after washing with water anddrying, melted at about 134O. On recrystallising from alcohol,colourless crystals were obtained, which melted and decomposed a t138O (corr.), as given by Knorr (Annalen, 1886, 236, 79) for thebromoacetoacetanilide which he obta’ined by brominating aceto-acetanilide. The identification was confirmed by taking a mixedmelting point with a sample of bromoacetoacetanilide prepared byKnorr’s method. When more than one molecular proportion ofaniline was added to the acid bromide, the second bromine atom wasalso attacked, and tarry substances were formed, from which a pureproduct could not be isolated. On dissolving the bromoaceto-acetanilide in cold concentrated sulphuric acid, keeping the solutionovernight, and then pouring into water, bromo-2-hydroxy-4-methyl-quinoline wits precipitated, which, after recrystallising from alcoholand drying, formed the curious felt-like mass described by Knorr,which melted and decomposed at 260° (corr.).Knorr (Zoc. cit.1990 CHICK AND WIISMORE : THE POLYMERISATION OF KETEN.p. 92) gives the melting point as circa 258O.” For comparison, asample of bromo-2-hydroxy-4-methylquinoline was prepared by theother method described by Knorr (Zoc. cit., p. 91). 2-Hydroxy-4-methylquinoline, obtained by digesting acetoacetanilide in thecold with concentrated sulphuric acid, was suspended in warmwater, and to the mixture bromine water was added until a per-manent yellow colour was produced, slightly more than one molecularproportion of bromine being required.The resulting bromo-2-hydroxy-4-methylquinoline was washed with water and r ecrystallised repeatedly from alcohol. I n appearance it was indis-tinguishable, even under the microscope, from the bromohydroxy-methylquinoline prepared from bromoacetoacetanilide, but itmelted, apparently without decomposing, at 273-275O (corr.),although it began to soften at 269-270°. A mixture of the twopreparations melted a t 240O.The y-bromoacetoacetyl bromide wm evidently an unstable sub-stance, as its solutions began to turn brown after a, few hours.Nevertheless an attempt was made to isolate it in a pure state. Asolution of it in carbon tetrachloride was prepared as before,starting with about 5 grams of cyclobutan-1 : 3-dione.The carbontetrachloride was removed by distilling under diminished pressure(100 to 30 mm.), and the liquid remaining in the flask was distilledunder 5 mm. pressure in a current of dry hydrogen. Between 1 and2 grams of an oily liquid passed over between 105O and l l O o , buthydrogen bromide was evolved at the same time, and a largeamount of a dark-coloured residue remained in the flask. Theliquid appeared colourless while on the end of the condenser tube,but was ligEt brown when observed in the test-tubes placed tocollect it. The best sample was sealed up as quickly as possible.It gradually darkened on keeping, and after a few days was nearlyopaque. The other samples reacted vigorously with water, withalcohol, and with aniline, and fumed strongly in moist air.Theresidue in the distilling flask appeared to consist largely of freecarbon, A small proportion, however, was soluble in chloroform,and the solution, when placed on the skin and washed with water,gave rise to a brilliant violet stain, which was very stable.Action of Sernicarbazide on cycloButan-1: 3-dione.To prepare the semicarbazide derivative, cyclobutan-1 : 3-dionewas treated with an aqueous solution of semicarbazide hydrochloridecontaining an excess of sodium acetate. A crystalline precipitatewas formed on keeping, which separated from warm water in smallCHICK AND WiLSMORE : THE POLYMERISATION OF KETEN. 1991rhombic ( 1) crystals, melting and decomposing slightly a t217-218O.The substance was insoluble in non-aqueous solvents,but was very soluble in dilute hydrochloric acid, and from thissolution platinic chloride precipitated a sparingly soluble platini-chloride. Owing to the small solubility of the base in cold water,and to the fact that it was decomposed by boiling water, themolecular weight could not be determined. Analysis, however,showed that it was the semicarbaaone-semicarbazide of acetoaceticacid:0.1210 gave 0.1448 CO, and 0.0626 H,O. C = 32.6 ; H = 5.6.0.1135 ,, 0'1388 CO, ,, 0.0570 HiO. C=33*4; H=5*6.0.1106 N=39.0.C,H,,O,N, requires C = 33.3 ; H = 5.6 ; N = 38.9 per cent.,, 37.1 C.C. N2 (dry) at 1 7 O and 751 mm.Action of Ammonia on cycloButan-1; %&one.To follow the reaction with ammonia, cyclobutan-1: 3-dione inquantities of about 3 grams was dissolved in dry ether -and placedin a U-tube, which was immersed in a freezing mixture of ice andsalt, kept at -loo to -15O.A slow current of ammonia gas,produced by warming aqueous ammonia, and dried by passing firstthrough a 50 per cent, solution of potassium hydroxide and thenover freshly ignited lime, was then passed through the solution inthe U-#tube. Almost immediately a solid substance commenced toseparate out; but after about twenty minutes oily drops of a yellowcolour began to make their appearance. The reaction was thenstopped, and the solid substance was quickly scraped on to a porousplate, which had previously been cooled to Oo.If the temperaturewas allowed to rise, or if the action of the ammonia was prolonged,the solid was completely converted into the yellow oil, from whichit could not again be recovered. The solid substance, after dryingon the porous plate, was usually pure (m. p. 5 4 O , corr.). It wasinsoluble in ether, but very soluble in water, alcohol, or glacialacetic acid. It could, however, be recrystallised most convenientlyfrom a mixture of acetone and light petroleum. The crystals werecolourless. The aqueous solution gave the violet colour characteristicof acetoacetic ester. On warming with aqueous alkalis, ammoniawas evolved, and if this solution was boiled with hydrochloric acid,carbon dioxide and acetone were given off, the latter being identifiedby the iodoform reaction, the alkaline mercuric chloride test, andthe formation with benzaldehyde of distyryl ketone, melting at 112O(corr.).Heating the substance directly with hydrochloric acidcaused decomposition with formation of brown compounds. O1992 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN.adding ammoniacal copper sulphate to the aqueous solution of thesubstance and ncutralising the ammouia, a grccn copper salt wasformed :0.1071 gave 0.1871 CO, and 0.0667 H,O.0.0765, in 19-59 glacial acetic acid, gave A t = - 0'157O.C,H70,N requires C=47.5 ; H = 6.9 per cent.C =47*6 ; I3 = 6.9.M.W. = 97.0.0798, ,, 19.59 ,, 9 , ,, ,, A t = -0.158O. M.W. = 101.M.W. = 101.The substance is therefore identical with the acetoacetamidedescribed by Claisen and Meyer (Ber., 1902, 35, 583), for which,however, they give a melting point of 50°.They did not determinethe molecular weight.The yellow oil formed by the further action of ammonia onacetoacetamide appears to bear some resemblance to the substanceobtained by Duisberg (dnnalen, 1882, 213, 174) by the action ofammonia on acetoacetic ester, from which, however, this author wasunable t o isolate a compound having a definite composition. It isbest prepared by the prolonged action of ammonia on cyclobutan-1 : 3-dione a t -loo to -15O. I f the reaction is started at theordinary temperature, much heat is evolved, and coloured decom-position products are formed. The U-tube may, however, beremoved from the freezing mixture as soon as all the solid aceto-acetamide has disappeared.The oil thus obtained always containedexcess of ammonia, which could not be completely removed, evenby passing a current of dry hydrogen through it for many hours,or by leaving it over sulphuric acid in a vacuum desiccator forseveral months, although the pressure was sometimes reduced to2 to 3 mm. As it was not soluble in any solvents which did notmix with water, it could not be purified by washing. It wasreadily soluble in water or alcohol, less readily so in acetone, andinsoluble in ether, benzene, light petroleum, chloroform, or carbontetrachloride, On exposure to moist air, a crystalline substancewas formed, which, after drying on a porous plate, melted at 147O.A quantity of this sufficient for an analysis could not, however, beobtained.On passing a current of dry hydrogen through the yellowoil a t l l O o , ammonia and water were given off. A t the end of anhour the substance had become very viscous, and portion takenout on a glass rod solidified on cooling. The remainder was thenwashed out of the tube with warm acetone, and, on cooling thesolution, a colonrless, crystalline compound separated out, whichmelted at 1 9 7 O (corr.). Recrystallisation from acetone did notalter the melting point. The compound was readily soluble inwater, alcohol, or glacial acetic acid, sparingly so in cold acetone,and insoluble in ether, benzene, or light petroleum. On warmingwith aqueous alkalis, ammonia was evolved. For a quantitativCHICK AND WJLSMORE : THE POLYMERISATION OF KETEN.1993estimation of the ammonia, the substance was distilled with2N-potassium hydroxide solution, the ammonia being caught instandard acid :0.1133 gave 0-2176 CO, and 0.0743 H,O.0.1063 ,, 21.5 C.C. N, (moist) at 19O and 752.8 mm.0.0765, in 17-75 glacial acetic acid, gave At = - 0.092O.0-0989, ,, 17.75 ,, 7, ,, ,, At = -0.128'. M.W. 4 7 0 .C,H,,O,N, requires C = 52.5 ; H = 7.1 ; N = 22.9 per cent.M.W. = 183.C =52.4; H=7.3.N=22*9.M.W. = 183.0.2369 gave 0-0233 NH,, that is, 183 grams C,H,,O,N, gave18.0 grams NH,.As stat,ed on p. 1982, we consider the substance to be 4-amino-2 : 4-d~methyZ-A2-tetrahydro-6-pyridone-3-carboxy~ade, 183 gramsof which should give 17 grams of ammonia on distilling with dilutealkalis.On acidifying the alkaline solution from which theammonia had been distilled with nitric acid, the free 4-amino-2 : 4-dimethyl-A~-tetrahydr~6-pyridone-3-carboxylic acid was not pre-cipitated, but the silver and barium salts appeared to be insolublein water. We propose to prepare larger quantities of the amidefrom acetoacetamide obtained by Claisen and Meyer's method (Zoc.cit .) .Action of Grignard's Reagent on cycloButan-1 : 3-dione.To study the action of Grignard's reagent (magnesium methyliodide), from 3 to 4 grams of cyclobutan-1: 3-dione were dissolvedin about 50 C.C. of dry ether contained in a large test-tube, andrather more than two molecular proportions of the reagent, dis-solved in about 100 C.C. of ether, were placed in a second tube ofabout 200 C.C.capacity. The reagent was kept at -78O by meansof a bath of solid carbon dioxide and alcohol, and the solution ofcyclobutan-1 : 3-dione was cooled to about -50°, a lower tem-perature than this causing the solute to crystallise out. Thereagent was kept vigorously stirred by means of a current of airdried over phosphoric oxide, and the solution of cyclobutan-1 : 3-dione was run in very slowly in a fine stream by means of awash-bottle arrangement, dry air under pressure being used to drivethe liquid over. Even at the low temperature of -78O, a brightyellow precipitate was at once formed. On allowing the tem-perature to rise, the precipitate turned brownish-red at about-40°, and became almost black above Oo. In this condition onlyresinous substances appeared to be formed when the mixture wasrun into ice-water.It was found preferable to add the etherealmixture slowly, as soon as it had reached -40° to -30°, to a2N-sulphuric acid solution, containing a slight excess of acid, whichVOL. XCVII. B 1994 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN.was kept partly frozen during the mixing by a freezing mixture.A t the end of the reaction, the ethereal solution was separated,and the aqueous solution was shaken with fresh ether, which wasadded t o the first. The ethereal solution was dried over calciumchloride and distilled, the pressure being reduced to 50-60 mm.after the ether had been removed. A small amount of liquidpassed over a t 80-looo, and a few drops of a bright yellow liquid,having a pleasant aromatic odour, at 180-200°. The last portionof this yellow liquid solidified in the condenser tube on cooling toyellow needles, which, after drying on a porous plate, melted a t145-146O.On adding water to the yellow liquid, more of theyellow solid was precipitated, leaving a nearly colourless solution.This was extracted with ether, the ethereal solution dried withcalcium chloride, and evaporated, when a small quantity of a highboiling liquid remained. This gave an orange-coloured solutionwith concentrated sulphuric acid, and, on pouring this into water,a small quantity of an oil was formed, which had an odourresembling that of mesityl oxide. The fraction of the lower boilingpoint also had an odour resembling that of mesityl oxide, and itgave a bright red colour with concentrated sulphuric acid.Aconsiderable amount of residue remained in the distilling flask,and resinous substances were also formed on neutralising andevaporating the aqueous solution.Owing to the poor yield, it was not possible to obtain a liquidhaving a definite boiling point. It is, however, probable from theforegoing that the reaction proceeds, a t any rate to a small extent,in the direction indicated on p. 1983. It is evident that some of theintermediate compounds, possibly including the compound formedwhen only one :CO group has been attacked, are very unstable,readily condensing to form resinous substances.Reduction of cycloButan-l : 3-diolze.This reduction promised to be of interest, but the choice ofmeans was limited.On account of the chemical nature of thesubstance, the more usual reducing agents were inadmissible, and,owing to the tendency to polymerise on heating, Sabatier andSenderens’ method was not promising. Accordingly, the methodof reduction by means of hydrogen and platinum black was selected.The hydrogen was prepared from zinc and dilute sulphuric acid,which were free from arsenic. The gas was passed through a tubepacked with copper gauze and kept at a red heat to absorb tracesof oxygen, which would otherwise have been reduced to water incontact with the platinum black, and it, was dried by means ofsulphuric acid contained in a spiral wash-bottle.The platinuCHICK AND WILSMORE : THE POLYMERISATION OF HETEN. 1995black was prepared by Loew's method (Ber., 1890, 23, 289). Itwas washed until free from chlorides, and was dried in a vacuumover sulphuric acid. The reduction vessel consisted of a large test-tube fitted with a rubber stopper, t'hrough which passed inlet andoutlet tubes for the hydrogen and a tap funnel. The inlet tubereached to the bottom of the reduction vessel. About 2 grams ofplatinum black were placed in the reduction tube, and the air inthe latter was replaced by hydrogen. The platinum black was thenagain dried by warming the tube to about 60°, and alternatelyexhausting with a Fleuss pump and filling with hydrogen. About4 grams of cyclobutan-1 : 3-dione, dissolved in dry ether, were thenintroduced through the tap funnel, and a slow current of hydrogenwas turned on, the lower end of the reaction vessel being placed ina water-bath to prevent cooling during the evaporation of theether.After about two hours, most of the ether had been drivenoff, and a spiral condenser fitted with taps, such as was used forcollecting keten, was attached to the outlet tube, and was surroundedby a bath of solid carbon dioxide and alcohol, in order to catchany volatile compounds which might otherwise be carried away bythe hydrogen. The water-bath was now warmed to about 6 5 O ,and was ma.intained at that temperature by means of an electricheater. After two days the odour of cyclobutan-1: 3-dione couldno longer be detected a t the outlet? tube of the reduction vessel ondetaching the Condenser, but a strong odour of butyric acid becamenoticeable when the connecting tubes were opened to the air.Thereduction vessel was then completely immersed in the water-bath,and the temperature was raised to about 9 5 O . After a furthertwelve hours, all the liquid had passed over into the condenser,which was found to contain a white, crystalline solid. A smallquantity of a brown residue remained with the platinum. I norder to ascertain whether any compounds had been formed whichwere gaseous at the ordinary temperature, the condenser wasattached to a manometer and to the Fleuss pump and exhaustedto about 5 mm. pressure. The tap leading to the pump was thenclosed, and the temperature was allowed to rise.The solid melteda t about -20°, but the pressure did not) rise above 50 mm., evenwhen the apparatus had attaine.d the temperature of the room.The condenser was then filled with dry air, after which it had tobe set aside for a few days. On again opening the taps, it wasnoticed that a, reduction of pressure had taken place, indicatingabsorption of oxygen. On transferring the contents of the con-denser to a distilling flask and distilling, the major portion passedover at 70--80°, and on reducing the pressure to 20 mm., a furtherportion passed over at about 80°. The first fraction had an odour6 ~ 1996 CHICK AND WILSMORE : THE POLYMERTSATTON OF KETEN.resembling that of acetaldehyde, but, on exposure to air, a strongodour of butyric acid was’ developed.This fraction also gave pro-nounced aldehyde reactions. The fraction of higher boiling pointhad a strong odour of butyric acid. It was readily soluble inwater, was acid to litmus, and liberated carbon dioxide fromsodium carbonate with formation of a very soluble crystallisablesalt. It boiled at 163--164O/757 mm. (corr.), and, after solidifyingin a freezing mixture, i t melted at. -7O to -6O. The substancewas therefore n-butyric acid, formed by the oxidation in air ofthe aldehyde. n-Butyraldehyde was accordingly the final productof the reduction of cyclobutan-1 : 3-dione by the method employed.The intermediate stages of the reaction are suggested on p. 1983.The water formed would, of course, combine with excess of cyclo-butan-1 : 3-dione to form acetoacetic acid, which, at the temperatureof the experiment, would decompose into carbon dioxide and acetone.It was anticipated, from analogy to the reduction of acetoaceticester with sodium amalgam, that aldol or ay-dihydroxybutane mighthave been formed, but no trace of these could be detected.Condensation of cycloButnn-1: S-dione.acetylketen ” slowly turnedbrown on keeping at the ordinary temperature, and that brownresins were formed when it was distilled under the atmosphericpressure. We have since found that when cyctobutan-1 : 3-dioneis heated in sealed tubes on a water-bath to 80-90°, it is convertedchiefly into dehydracetic acid, the reaction being complete aftertwo to three hours.A certain amount of brown resins and ofcarbon dioxide are, however, formed at the same time. Also,in some samples, which had been sealed up in glass tubes and keptat the ordinary temperature, crystals of dehydracetic acid madetheir appearance after several weeks ; but here again brown resinsand carbon dioxide were also produced.The yield of dehydraceticacid was, however, the greater the lower the temperature at whichcondensation took place. Condensation did not. appear t o beaccelerated by the action of light, for a sample of cyclobutan-1 : 3-dione, which had been sealed up in a bulb of “ uviol ” glass andexposed to bright sunlight’, did not turn brown more rapidly thanother samples kept in the dark at the same temperature. On theother hand, cyclobutan-1: 3-dione is the more stable the lower thetemperature at which it has been distilled. From the formationof brown resins and of carbon dioxide along with the dehydraceticacid, it is evident that the condensation follows more than onecourse.On a.ccount of the manifold reactions of the multiple ketenI n our former paper we stated thaCHICK AND WILSMOHE : THE POLYMERISATION OF KETEN. 1997groups, for the study of which dehydracetic acid has been thechief starting point, notably in the hands of Collie and his pupils(compare Trans., 1907, 91, 1806), the proof of the formation ofthis compound from cyclobutan-1 : 3-dione, and consequently fromketen itself, was of special importance. After recrystallisation, thedehydracetic acid melted at 109O (corr.), and the melting point wasnot altered by mixing with a sample of pure dehydracetic acid fromother sources.Under the microscope the two samples appearedto be identical when they had been crystallised in the same way.The dehydracetic acid from cyclobutan-1: 3-dione also gave anorange colour with ferric chloride. Finally, it was converted bythe usual method into diacetylacetone, which was identified by theyellow barium salt and the characteristic violet colour with ferricchloride.Condensation of cycloButawl : 3-dione in Presence of Quinoline.The condensation of cyclobutan-1 : 3-dione in the presence ofquinoline has also been further investigated. Quantities of about5 grams of cyclobutan-1 : 3-dione were mixed with an approximatelyequal amount of pure quinoline in a wide test-tube, to which wasfitted a rubber stopper and a mercury valve to allow of the escapeof gas and at the same time to exclude air.After two or threedays yellow crystals appeared in the tube, and the supernatantliquid became dark brown, while carbon dioxide was slowly givenoff. After ten days to a fortnight the reaction appeared to becomplete, and the contents of the tube, now become very viscous,were scraped out into a mortar and ground up with acetone, inwhich the yellow crystals were not soluble. The yellow substancewas then collected and washed thoroughly with acetone, after whichit was dissolved in hot glacial acetic acid and reprecipitated by theaddition of water. It was usually pure after one such re-crystallisation, melting at 2 4 4 O (corr.).(In our former paper wegave 231O as the melting point, but the substance then availablewas not quite pure.) The yield was not good, being only about20 per cent. of the weight of cyclobutan-1: 3-dione taken, and thiswas much reduced if impure quinoline had been used. The acetonefiltrate from the yellow compound was dark reddish-brown whenviewed by transmitted light, and had a marked green fluorescenceby reflected light. It contained only resinous substances, fromwhich a pure compound could not be isolated.It was difficult to obtain satisfactorily consistent analyticalnumbers, probably owing to the formation of met.hane on heating :0.0848 gave 0.2258 CO, and 0.0367 H,O. C =72.6; H =4-8.0'1100 ,> 0'2931 CO, ,, 0.0468 HiO. C=72.7; H-4.71998 CHICK AND WILSMORE : THE POLYMERISATION OF KETEN.0.0683, in 18.94 glacial acetic acid, gave A t = - 0'066O.M.W. = 213.0.0693, ,,* 17.63 ,, ,, ,, ,, A t = - 0'068O. M.W. = 225.0.0531, ,, 17.85 ,, ,, ,, ,, E=0.032. M.W.=235.CI3Hl0O3 requires C = 72.9 ; H = 4.7 per cent. M.W. = 214.The substance was readily soluble in hot glacial acetic acid, butmuch less so in the cold acid, crystallising on cooling in brightyellow needles or plates. The solutions were bright yellow, with agreen fluorescence. It was slightly soluble in benzene, almostinsoluble in alcohol or acetone, and insoluble in water, chloroform,light petroleum, or ether. It was soluble in dilute alcoholic potash,forming a red solution from which it could be reprecipitated in asomewhat impure form by hydrochloric acid.A suspension of thesubstance in water was neutral t o litmus, but addition of ferricchloride gave a red colour, which was not discharged by dilutehydrochloric acid. It was insoluble in aqueous alkalis, and it didnot react with benzoyl chloride, so that hydroxyl groups wouldappear to be absent. It dissolved on warming with 75 per cent.sulphuric acid, forming a deep yellow solution with a greenfluorescence, but the original substance could not be recovered byneutralising the acid. Some reaction had therefore taken place,probably the removal of a side chain.As the yellow compound had a strong resemblance to certainnaphthalene derivatives discovered by Collie (Trans., 1893, 63, 329 ;1896, 69, 293), an attempt was made to prepare the parent hydro-carbon.Owing to the smal! quantity of material available,distillation with zinc dust did not offer much prospect of success,and electrolytic reduction was therefore tried. The solution of thesubstance in sulphuric acid was diluted until the strength of theacid was about 25 per cent., and was placed in a porous pot,together with a cathode of platinum gauze, which could be rapidlyrotated. To prevent formation of oxidising substances, an amal-gamated zinc plate was used for the anode, a slow stream of 25 percent. sulphuric acid being made to flow through the anode vessel toremove the bulk of the zinc which dissolved. The current densitywas about 0.1 ampere per sq.cm. After electrolysis had proceededfor some hours, the cathode solution wi~s shaken with benzene, and,on evaporation of the latter, a minute quantity of a colourlesssubstance, melting at 96-97O, wm obtained. The yield could notbe improved. Substitution of a zinc cathode for the platinum gaveonly oily substances, which could not be caused to crystallise, andwhich were too small in quantity for effective distillation.A suspension of the substance in carbon tetrachloride decoloriseda solution of bromine in the same solvent. A crystalline substanceappeared to be formed at first, but it dissolved on further additioCHICK AND WILSMORE : THE POLYMERISATION OF KETEN. 1999of bromine. On shaking the mixture with water, hydrobromicacid could be detected in the latter.I n the quantitative experi-ments weighed quantities of the substance were shaken with amoderate excess of bromine solution, and, when the substance hadcompletely dissolved, the excess of bromine was determined bymeans of potassium iodide and thiosulphate in the usual way. Thefree acid was then found by titration with standard alkali. Thebromine solution contained 0.0275 gram equivalent per litre andthe alkali 0.0384 equivalent:0.0707 gram required 25-64 C.C. bromine solution and 15.99 C.C.alkali.Or 214 grams reacted with 2.13 equivalents of bromine, forming1-86 equivalents of acid.0.0757 gram required 26.37 C.C. bromine and 16.68 C.C. alkali.Or 214 grams reacted with 2.05 equivalents of bromine, forming1-81 equivalenh of acid.The formation of nearly two equivalents of acid from twoequivalents of bromine would seem to indica.te the formation of anacid bromide, as in the reaction between bromine and keten(Trans., 1907, 91, 1941), or in that between bromine and cyclo-butan-1 : 3-dione described above, this acid bromide on addition ofwater giving one equivalent of hydrobromic acid and one of anotheracid.The yellow compound was attacked by dilute permanganate inthe cold, but only acetic acid could be detected among the productsof oxidation.It also reacted with phenylhydrazine in glacialacetic acid, forming a compound containing nitrogen, which wasinsoluble in benzene but very soluble in alcohol, from which it couldbe crystallised in colourless needles or plates, melting sharply at238O. A quantity sufficient for analysis could, however, not beobtained.On treatment with an alkaline solution of hydroxylamine, anoxime was formed. The yellow compound was dissolved in asolution containing 10 grams of potassium hydroxide t o 20 C.C. ofwater with 120 C.C. of alcohol. Excess of hydroxyIamine hydro-chloride dissolved in a little water was added, and the mixture waswarmed for five minutes on the water-bath. On heutralising withhydrochloric acid, a yellow substance slowly separated, precipitationbeing complete in about two hours. It was washed with water andrecrystallised from hot water. It was also soluble in alcohol. Itmelted and decomposed a t 200° (corr.). The results of analysisseem to show that we did not succeed in getting this substance ina completely pure state; in fact, it could not be dissolved withoutshowing signs of decomposition 2000 APPLEOEY: THE VISCOSITY OF SALT SOLUTIONS.0.1072 gave 0.2336 CO, and 0.0576 H,O. C= 59.4 ; H = 6.0.0.1030 ,, 0.2342 CO, ,, 0.0517 H20. C=61*5; H=5*6.0.1084 ,, 0.2436 CO, ,, 0.0555 HiO. C=61.3; H=5.7.0.1126I. C13Hl,03N, requires C = 63.9 ; H = 4.9 ; N = 11.5 per cent.Formula I results from the reaction of hydroxylamine with two,, 9-98 C.C. N, (moist3 at 18-5O and 761.6 mm. N= 10-2.11. C13H1404N2 ,, C=59*5; H=5*3; N=10.7 ,,:CO groups according to the equation:C13HIoO3 + 2NH,*OH =C13H12O,N, + 2H2O.Formula I1 represents the reaction of two molecules of hydroxyl-amine, one reacting normally with a :GO group, and the otheradding on to a double bond:C13H1003 + 2NH,*OH = C13H1404N2 + H20.The aqueous solution of the hydroxylamine compound was acidIt was titrated with standard alkali containing 0.0384 to litmus.equivalent per litre :0-0777 gram required 6-23 C.C. alkali.That is, 244 grams C13H,,03N2 require 0.75 equivalent of alkali,and 262 grams C13H1404N, require 0.81 equivalent of alkali.It will be seen fram the foregoing that so far we have found noclue to the const'itution of the yellow condensation product of cyclo-butan-1 : 3-dione, and the yield in the preparation of the substanceand of all its derivatives is so poor that very much larger quantitiesof the raw material (that is, of cyclobutan-1: 3-dione) than havebeen hitherto available would be required before this portion ofthe research could be resumed with any chance of success.DNIVERSITY COLLEGE,UNIVERSITY OF LONDON

ISSN:0368-1645    

DOI:10.1039/CT9109701978

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

2000 APPLEOEY: THE VISCOSITY OF SALT SOLUTIONS.CCX1.-The Viscosity of Salt Solutions.By MALCOLM PERCIVAL APPLEBEY.THE changes in viscosity produced when salts are dissolved inwater have been the subject of many important researches sincePoiseuille's classical work on the flow of liquids in capillary tubes.The results obtained by the earlier workers in this field may besummarised a,s follows :(1) The effect of salts on the viscosity of water is small, but;generally positive. Some salts, however (for example, potassiumchloride), diminish the viscosity of water.(2) The effect of salts in increasing the viscosity increases morAPPLEUEY : THE VISCOSITY OF SALT SOLUTIONS. 2001rapidly than the concentration ; the salts wliich diminish theviscosity have, however, less effect as concentration increases.Aminimum value is reached a t a certain concentration. The additionof more salt then raises the viscosity.(3) The effect of a salt in increasing the viscosity of water isadditively composed of a factor expressing the effect of the cationand a factor expressing the effect of the anion, when the solution issufficiently dilute.(4) The temperature-coefficient of the viscosity of a dilute saltsolution is approximately equal to that of water.These researches were necessarily confined to concentrated s o htions, since the methods used were not of sufficient accuracy t omeasure the small changes in viscosity produced by small quantitiesof dissolved salt. It should also be noted that the earlier work isvitiated by the fact that the authors did not investigate thebehaviour of their apparatus with respect to Poiseuille’s law, butalways assumed its rigid validity.The velocity of flow in theviscometers used was always greater than the limiting velocity atwhich eddying begins, and aboke which Poiseuille’s law is notrigidly obeyed. The error thus caused in the determinations cannotbe calculated from the data given.Within recent years attention has been directed to the phenomenaof viscosity in dilute solutions. The work of Kohlrausch (Proc.Roy. Soc., 1903, 71, 338) and that of Bousfield and Lowry (Phil.Trans., 1905, 204, A , 253) has shown the importance of studyingchanges of viscosity for the interpretation of the results obtainedin conductivity determinations. The applica.tion of Stokes’ theoremto strong eIectrolytes has made the knowledge of the viscosityeffect of salts in dilute solution of great importance in the measure-ment of ionisation and the application of the dilution law to thesesolutions.The advance in the accuracy of relative viscosity deter-minations necessary for the investigation of these problems wassecured by the important work of Gruneisen (Wiss. A bh. Phys.-Tech.Reichs., 1905, 4, 151). The theory of the viscometer was verythoroughly investigated by him, and methods of standardisationwere developed which enabled him t o determine the deviation ofany viscometer used from the simple Poiseuille law. His experi-ments were a11 corrected for this deviation, and furnish the firstaccurate determinations of viscosity in dilute solutions.Investigations have also been carried out by Hosking (Phil.Mag.,1904, [ ~ i ] , 7, 469), who has studied the effect of temperature andconcentration over wide limits for lithium chloride, whilst Bousfieldand Lowry (Phil. Trans., 1906, 206, A , 101) have also made someobservations on dilute solutions2002 APPLEBEY: THE VISCOSITY OF SALT SOLUTIONS.The work of Griineisen is remarkable for the discovery of ageneral phenomenon which the less exact methods of earlier workershad not revealed. He has shown that the viscosity-concentrationcurve for all salts has a change of curvature at the dilute end inthe sense that the first particles of salt added to water have agreater effect in increasing, or a less effect in diminishing, theviscosity of water than subsequent additions. The change ofcurvature is scarcely noticeable unless the curve is plotted on avery large scale.A much more convenient method is to plot thedifferential quantity :Relative viscosity - 1Molecular concentration’against the cube-root of t.he concentration as recommended byGruneisen.This change of curvature was observed by Griineisen with everymember of a large series of salts investigated by him. No sucheffect has ever been found in solutions of non-electrolytes. It isnot surprising therefore that Griineisen has endeavoured to connectthe phenomenon with ionisation. The following formula given byhim corresponds with the observations with fair accuracy over aconsiderable range :~- VI’lO- - Aa + B(l - a) + Cm,rnwhere ?/’lo = relative viscosity,m = molecular concentration,Q =degree of ionisation,The present work was undertaken with the following objects :(1) To carry the investigations to greater dilutions thanGriineisen reached, and thus t o thest his formula;(2) To determine the effect of temperature, especially in dilutesolutions ; and(3) To investigate the connexion between the viscosity of itsolution and its molecular and ionic conditions.Materials.-It was thought advisable t o investigate thoroughlysome one salt over wide ranges of temperature and concentration.Lithium nitrate was chosen, as its high solubility permits theinvestigations to be carried to very high concentrations.It wasobtained either from Kahlbaum or from Merck in the form ofcrystalline lumps with an indefinite amount of water of crys-tallisation. It appeared to be a mixture of the two hydrates,LiN03,4H20 and LiN0,,3H20, described by Donnan and Burt(Trans., 1903, 83, 335). It was recrystallised before use in the formof the trihydrate. A spectroscopic examination showed noand A , B, and C are constantsAPPLEHEY: THE VISCOSITY OF SALT SOLUTIONS. 2003impurities except a trace of sodium. The water used was con-ductivity water free from dust. The dissolved air was removed byexhaustion in the cold just before use. This precaution is necessaryto prevent the appearance of air-bubbles in the apparatus duringdeterminations.I'repumtion G f Solutions.-The anhydrous salt is extremelyhygroscopic, and very prolonged heating is necessary to bring it toa constant weight.The making up of solutions by weight is thus avery tedious process. It was therefore decided to determine theconcentration of the solutions used by means of a previously deter-mined density curve at 2 5 O . The dehydrationthis purpose did not present such difficulties, asless of the salt was necessary for a determination.The labour was also much lessened by the useof a specimen crystallised at about 70°, whichwas practically anhydrous. An appropriateweight of the salt was dehydrated by heating it,for at least twenty-four hours in a smallplatinum crucible in an air-bath heated by boil-ing aniline. The crucible was allowed to coolin a desiccator, and then weighed in a stopperedglass bottle.The correct weight of water wasthen weighed into a widemouthed stopperedbottle, and the crucible dropped in.Density Determinations.--The determinationsa t 2 5 O and 1 8 O were made in U-shaped pykno-meters of test-tube glass, holding about 10 C.C.Each pyknometer was weighed against a counter-poise, and the results were corrected fordisplaced air. The density of each solution wasdetermined with two separate pyknometers.On account of the expansion of the solutionbefore weighing, these pyknometers couldnot be used at Oo. The form shown inof the salt forFIG. 1.Fig. 1 was used for this temperature. The pyknometers used heldabout 20 C.C. The results usually agreed to 0.00002, although theagreement was not always so good at Oo.This is due, in part, tothe difficulty of temperature regulation, and in part to the con-tamination of the ground surface, in which the stopper fits, withsolution in some experiments. Simple wiping with a filter-paper(the usual method of cleaning the open end of a pyknometer) failsto remove this. The error might have been avoided if the stopperhad been ground on outside instead of inside the open end of thepyknonieter. F o r the purpose of viscosity determinations, however2004 APPLEBEY : THE VlSCOSlTY OF SALT SOLU'l'lUNS.an accuracy of 0*0001 is amply sufficient at Oo, and the errors werenever so large as this.Thefollowing equatibn was found to express the results with sufficientexactness to justify its use for calculating concentrations :where 8 = density of solution,The densities determined a t 25*01° are given in table I.~ ~ = 2 5 .1 0 3 (S - so) - 16.33'7 (S - sJ2,so = density of water,rn = concentration expressed in gram-molecules per 1000 gramsThe degree of accuracy obtained in determining concentrations inof solution,this manner may be seen by the second column of table I.TABLE I.--Densi{y of solutions of lithium nitmte at 25.01O.Concen tra1 ioncalculatedConcentration. from equation.0.0 0.00-1296 0.12960.1378 0.13880-1458 0.14630'1571 0.15770'1'124 0'17280-1971 0.198 10,2137 0.21 440'3145 0.31370.3255 0.32380.3605 0.36060,3905 0.3899"0.4248 0'40160'4851 0.48550'6066 0.60610 8283 0.82810.9059 0'9050*O '9960 0.98611 '0968 1.09601'2763 1.27521.8639 1.86332.2027 2'20202'4602 2.45913,4086 3'4093*5?376 5'849D25.01"4",-- \APyknometer PyknometcrI.11.1.00225 -1 *00262 1 '002631.00293 1 *002911.00338 1 -003381.00396 -1-00500 1005001.00565 1.005671 *00967 1.009io1'01008 1'010081-01158 1 -011551.01275 1.012771.01325 1.013251'01664 1-016681.02160 1.021631.03077 1 030821.03400 1'034021-03741 1.037411.04206 1 '042051.04967 1 -049671.07529 1'075271'09047 1.090471.10223 -1'14759 1'147581 -28344 1 '28340- -Meandensity.0.997071.002251.002621.002921.003381 '003961 *005001 .OD5661009691~010081.011571.012761 '01 3251 -0 16661-021611'030801'034011'0374 11 -042051'04967l.Oi5281'090471'102231'1 45591'28342The three solutioiis marked with asterisks show divergences con-siderably greater than the errors in determining the increase indensity.I n all three cases the concentrations calculated from thedensities are smaller than those calculated from the weighings.It is most probable that the salt used in these experiments was notfully dehydrated. These values have been omitted in calculatingthe constants of the equation.The The densities at 1 8 O and Oo are given in tables V and VIAPPLEBEY: THE VISCOSITY OF SALT SOLUTIONS. 2005values at 1 8 O agree very well with those determined by Kohlrauschand used by Gruneisen. The density determined by Perkin (Trans.,1893, 63, 68) for a 2-63 weight-normal solution (=18*17 per cent.)at 25O is, however, considerably higher than that read off mycurve.Viscosity Determinations.--The use of viscometers of the Ostwaldtype in the measurement of relative viscosity depends on thevalidity of the law of Poiseuille, which is expressed by the equation :7 r p 4 t?I= -*lv 9where q is the coefficient of absolute viscosity,p is the mean pressure producing flow,Yis the volume of liquid which flows through the capillary inthe time t,c is the radius, andE the length of the capillary.Since r, I, and V are constants depending only on the dimensionsof the viscometer, the relation :7 = pt x constantshould hold good for different liquids in the same viscometer, andif experiments are carried out with the same liquid flowing underdifferent pressures, the product pt will have a constant value whenthe viscometer obeys Poiseuille’s law.Griineisen (Zoc.cit.) has shown that this condit.ion is by no meansrigidly fulfilled by viscometers of the Ostwald type acting undertheir own hydrostatic pressure. He has found that the variationof pt is due to the fact that above a certain limiting velocity theflow of liquid in the viscometer is not steady, but that some of thepotential energy is expended in forming eddies within the liquid.Hence the liquid is not forced down the capillary so quickly as itshould be if Poiseuille’s law held good, that is, t is greater thandemanded by the simple law, and in consequence pt has a greatervalue than the ccnstant found with slow flow.Thus the phenomena of flow under varying pressures may besummarised as follows.When the pressure is small and the timelarge, pt is constant; on increasing the pressure and diminishingthe time, a point is reached where eddy-formation begins. Beyondthis point pt continually increases, and Poiseuille’s law no longerholds. The readings of a viscometer are only trustworthy whenthe time of flow is so large as to ensure that the product pt remainsconstant (for the same liquid) over the whole range of variation intime of flow to be observed in the actual determinations. Griineisenhas tested several viscometers in a manner similar to that to bedescribed later, and has published ( h e .cit.) the pt-t curve2006 APPLEBEY : THE VISCOSlTY OF SALT SOLUTIONS,obtained. He has then calculated a correction for the variation inp t over the region of his experiments, and applied this throughouthis work.It was thought possible to construct viscometers in which thiscorrection should be negligible by reducing the velocity of flowconsiderably below the limits attained by Gruneisen.This diminution in velocity of flow may be secured in threedistinct ways :(a) By reducing the diameter of the capillary.( b ) By lengthening the capillary.( c ) By reducing the hydrostatic pressure in the viscometer bybringing the two bulbs as near together as possible.(a) Some experiments were tried with viscometers constructedwith very fine capillaries.It was found, however, that the resultswere almost invariably vitiated by dust. The final form ofviscometer adopted had a capillary radius of about 0.2 mm.; thusmy tubes were considerably smaller than Gruneisen's, the radius ofwhich varied between 0.34 and 0.48 mm.( b ) and ( c ) To lengthen the capillary in the ordinary Ostwaldtype of viscometer is to increase the pressure proportionally. Theform shown in Fig. 2 was therefore adopted.* The bulbs cannotbe brought nearer together than a certain limiting distance depend-ing on the capillary rise in the viscometer; otherwise the liquidnever falls below the lower mark. I n the viscometers used, thelower mark was etched very near to the bulb where the capillarywits slightly enlarged.At the completion of the experiment, themeniscus came to rest a few millimetres below the mark. Thedimensions of the viscometers finally adopted were :Radius of capillary ..................... 0.2 mni.Length of capillary .....................Volume of bulb ...........................Mean difference of level .............. 10.8 cm. (approx.).How far the results given by any particular viscometer are vitiatedby eddy-formation also depends on the amount of irregularity in thecapillary (and especially at the ends of the capillary, where the flowsuddenly changes). I n the construction of a viscometer anythingapproaching a sudden change of diameter should be avoided. Thejunction of capillary and bulb should have the form of a smoothcone, as shown in Fig.2.11 t o 22 em.7 C.C. (approx.).* The same object has been attained by Griineisen by winding the capillary in aspiral. This method is, however, open to the objection that much of the energywhich should be expended in driving the liquid on is used iu changing the directinnof flow as the capillary bends. This results in a very high valne for the Griineiseneddy-correction. Since it was hoped to avoid the Griinciseii correction altogether 110experiments have been performed with spiral capillariesAPPLEBEV : THE VISCOSITY OF SALT SOLtJ’rIONS. 2007St an dard isat i o n of I’iscom e t e rs .-Alt hough from the dimensionsof the viscometers it was probable that Poiseuille’s law would beobeyed within the limits of experimental error, it was necessaryto carry out special tests so as to be certain that irregularities inthe glass were not present of such magnitude as to produce eddiesand thereby cause the viscometers to disobey the simple law. Themethod here described is similar to that used by Griineisen.I norder to test a viscometer, it is necessary to observe its time offlow under varying pressures when filled with water, and toinvestigate the variation of the product pt. The pressure in anyFIG. 2.K rirr, a c 0particular experiment is the sum of the external preksure appliedand the hydrostatic pressure due to the head of liquid in theviscometer. The latter varies during the experiment, and anaverage value has to be found in the following way.First, the small arm of the viscometer is attached to a, watermanometer, and the pressure directly read off by means of a,reading-telescope and scale, together with the level at which thewater stands in the viscometer.This determination is repeated forseveral different positions of the liquid in the viscometer, and acurve is drawn representing the variation in pressure head as th2008 APPLEREP : THE VISCOSITY OF SALT SOLIJTIONS.liquid falls in the viscometer. Secondly, by means of the reading-telescope, the time necessary for flow from the upper mark toknown distances below the mark is measured. By combining thesecurves, namely, variation of pressure with depth and variation oftime with depth, a curve is drawn which shows the variation ofpressure with time throughout the whole tube.From this a, valueis obtained for the average hydrostatic pressure during flow. Thisis usually approximately equal to the pressure at mean time, butdiffers from that calculated from the difference of level at meantime owing to surface effects; for exa.mple, in one viscometer :Meail hydrostatic prcssurc ......... 10.60 cm. of water at 25"Pressure at mean time , , . ...... ... ... 10'55 ,, ,, ,,Difference of level a t mean time ... 10.99 ,, ,, ,,measures the surface-tension effect, and will be considered later.The difference between the first and third of these numbersFIG. 3.The times of flow have now to be measured when a known escessof pressure is applied at the small arm of the viscometer. For thispurpose it is necessary to have an arrangement capable of exertinga small pressure, which shall keep quite constant during theexperiment.'I have found the apparatus shown in Fig. 3 to workvery satisfactorily. The vessels A and B, which contained water,were so large that the movement of the air into the bulb of theviscometer during flow made no measurable alteration in thedifference of level in A and B measured by the water manometer C.The pressure of the air in B remained constant t o 0.1 mm. ofwater during the experiment when the cork of B and the rubberconnexions were painted with celluloid varnish so as to preventleakage. The pressure in B can be varied by allowing air to escapefrom D or by forcing in air with a bicycle-pump at E. The rangAPPLEIZEP : THE VISCOSITT OF SALT SOLUTIONS.200910.94 758 '4 829711 *205 739.5 828611.93 695 8 830113-15 630'8 829513.69 605.0 828214.38 5i7.5 530414-85 558.8 829815.23 543.6 827915.83 524 ' 6 830416 '47 503.6 829417'14 483.6 828917.85 466*0 831818 '54 447'6 829919.26 431.4 830920.09 415.7 831120.96 396-5 831121.61 384.6 831121,868 380.8 832622.89 363.9 833023-94 348.5 834324.20 344.0 832524-75 337 2 834625*20 331.1 834425.68 3252 838125-94 321.7 834527.27 307.4 8383FIG. 4.Pressurex titne.840083008200300 400 500 600 700 800 secs.values of p t , although varying considerably, do not, a t low pressures,differ by more than the experimental error. A t higher pressures,p t rises above its normal value, the increase becoming rapid as thepressure increases.The experimental error in standardising isunfortunately much greater than that of the viscosity deter-minations. It is thus not quite certain that the tube obeysPoiseuille's law with the necessary accuracy. The following facts,however, indicate that the assumption is justifiable :(1) Within the attainable limits of accuracy of standardisationno deviation from Poiseuille's law can be detected until the timeof flow falls well below the minimum time of flow in the actualdeterminations.VOL. XCVII. G 2010 APPLEBEP: THE VISCOSITY OF SALT SOLUTIONS.(2) The times of flow of any pair of tubes filled with water werein the same ratio as the times of flow for any solution determined.This shows that either the tubes obey the law rigidly, or that theyall deviate to the same extent.(3) The velocity of flow in the capillaries of my viscometer isonly about one-fifth of that prevailing in Gruneisen’s experiments.The correction applied by him for deviakion from Poiseuille’s lawis only 0.045 per cent, for a normal solution of lithium nitrate.It is therefore probable that the deviation of my tubes fromPoiseuille’s law is not more than 0.01 per cent., and is consequentlynegligible for solutions less concentrated than normal.Time.-This was measured by means of a carefully tested stop-watch, which was always in a constant state as regards winding atthe beginning of each determination (the watch was always woundto its fullest extent half an hour before filling the viscometer). I nthe later experiments an electromagnetic device wits used to startand stop the watch.The error in time determinations with astop-watch is not greater than 0.2 sec., and with a large numberof determinations the error of the mean result is not more than0.1 sec. In view ofthe magnitude of the other errors of the determinations, particularlythe temperature effect, since with water a difference of 0.005O a t1 8 O produces a change of 0.2 sec. in the time of flow of the quickesttube used, it seemed useless to attempt any more accurate deter-mination of time.Cleaning.-As the deposition of the least particle of solid inthe capillary introduces errors far larger than the variations inviscosity which tho viscometers were designed to measure, it is ofthe greatest importance to clean the tubes thoroughly after eachdetermination with water containing no solid matter in solutionor suspended.I n this research, conductivity water made by distillation in aclosed apparatus (Hartley, Campbell, and Poole, Trans., 1908, 93,428) was used for washing the tubes.Before use it was carefullyexamined to see whether it contained any solid matter.The conductivity of water gives no certain indication of itssuitability f o r this purpose, for the conducting impurities remainingin a sample of good, distilled water are volatile (carbon dioxide andammonia) and have no effect in the viscometer, whilst, on the otherhand, organic impurities or suspended solids render the wateruseless, although their presence is not indicated by conductivitydeterminations.Consequently those samples of water which showedno suspended solid were chosen rather than those with a lowconductivity. The average conductivity of the water used wmThis is an error of 1 in 8000 at its maximumAPPLEBEY : THE V[SCOSITY OF SALT SOLUTIONS. 2011about 1 x 10-6 mho at 18O. The water was quite free from organicimpurities.In spite of all precautions, the tubes frequently became con-taminated with dust. When this happened, the tube was chargedwith a few C.C. of nitric acid and one drop of alcohol, and leftovernight.The presence of dust is betrayed by (1) the irregularity of theresults; (2) the failure of the tube to give the same time of flowfor water after washing and drying.After cleaning, the tube is dried by gentle heating, while itcurrent of air, freed from dust by passage through cotton-wool, isdrawn through it.Filling.-The viscometers are filled by pipettes of such contentas to fill them from the middle of the upper to the middle of thelower bulb.With this arrangement the alteration of hydrostaticpressure due to small variations in the volume filled in by thepipette is a minimum. The liquid (and, if necessary, the pipette)to be used is first brought to the temperature at which the experi-ment is to take place. The error of the pipettes was measured byweighing successive fillings of water. The greatest variation in sixfillings of an 8.7 C.C. pipette was 0.0022 C.C. Since the averagediameter of the lower bulbs of the viscometers at their widestparts was 3.8 cm., the greatest error occasioned by variations inthe volume of liquid delivered by the pipette will bein the head of liquid, and since the average head is 10.6 cm.ofwater, the error so occasioned is only 0.002 per cent., which isconsiderably less than the errors in determining the times of flow.The use of a pipette for filling the viscometer is therefore justified.When filled, the viscometer is fitted with the apparatus shownin Fig. 2 ( A ) , the object of which is to allow the liquid in theviscometer to be forced up the capillary, and to run down withoutcontact with dusty air. The liquid is forced up by pinching therubber tubing A , and applying pressure by means of it small hand-bellows a t B.The air which enters is freed from dust by a tightcotton-wool plug in C.* When the liquid has risen above theupper mark, the tube A is released, and the air pressure equalisesitself on the two sides of the viscometer. During the actual experi-ment no air from the outside enters. The friction of the air in Awas found to be negligible.As it is of great importance that the viscometer should be fixed* When the liquid in the viscometer is hygroscopic, and in all low temperatureexperiments the air is dried before passing into B.6 Q 2012 APPLEREP : THE VISCOSITY OF SALT SOLUTIONS.rigidly and always in exactly the same position, a special holder wasdesigned [Fig. 2 (B)]. The viscometer is fixed by means of thescrew A with its wider arm resting in two V grooves 13, B and across ( x in Fig.2) etched on the capillary, resting upon a linescratched on the sidepiece C. The whole apparatus, which isconstructed of stout brass, is now fitted on the brass plate D, threesteel pointe E, E, E fitting exactly into three conical holes F, F, P.The points being fitted, the two parts are fixed together rigidly bya nut which is screwed down on the screw G, which passes througha hole in the front plate. (The nut must not. be screwed down tootightly, or the steel points may be distorted.)The back plate is firmly attached to a wooden cross-piece supportedby two wooden uprights fixed firmly to the bench and supportedby stays so as t o be very rigid. The wooden parts were made ofwell-seasoned wood to avoid warping.With this apparahs theviscometer can be brought to exactly the same position for eachdetermination.Temperature.-Experiments were carried out at 25O, No, and Oo.For the experiments a t 25O and 18O the viscometers were immersedin thermostats holding 30 to 40 litres of water, which was kept inrapid motion by a good stirrer. Constancy of temperature wassecured by Lowry spiral regulators, gas heating being used for the25O bath, electric for the 18O bath. No variation of temperaturewaa ever observed on a thermometer divided into wide twentieths,which could be read t o 0-005°. The Oo bath was a well-stirredmixture of crushed ice and water. It usually remained constantt o 0'02O during an experiment. The results were calculated to Ooby the use of a temperature correction.Method of Ezperiment.-The time of flow is found for pureconductivity water, viscometer and pipette are then dried, and thesolution t o be determined is filled in.The time of flow is thenmeasured several times. Finally, the viscometer and pipette areagain cleaned and dried, and the water value is again determined.This precaution is necessary, as the water values sometimes slowlyincrease during successive fillings, owing to contamination withorganic matter or incomplete washings, and the change is so smallas to escape notice in any other way. In most of the determinationsperformed in this research, the original and final water valuesagreed to 0.2 sec. I n a few cases, where it was obvious by theappearance of a large and irregular water value after a constantsolution value that contamination had occurred in the final waterfilling only, the original water value was used in calculation.Calculation of Results.-The simple Poiseuille law gives APPLEBEY: THE VlSCOSlTY OF SALT SOLUTIONS.2013where 7 = viscosity,t = time of flow,p = hydrostatic pressure in the tube, andq0, to, and p , are the corresponding values for water.The average pressure producing flow is that of a column of waterequal to the mean difference in level diminished by a, quantityexpressing the buoyancy OP the air in which the experiment takesplace, and by a quantity depending on the surface effects, pro-portional to the surface tension.This pressure has been determinedin the course of standardising the tubes. It is equal to:where H = mean difference of level,H(S0 - A) - Kyo,so = density of water,A = 97 9 , air,yo = surface tension of water,K = a constant depending on the form of the apparatus.All the other terms in this expression being known, the constantThe pressure for the liquid to be determined will be:The relative viscosity q/q, is therefore given by the expression :andcan be evaluated.H(s - A) - Ky.or t H(8 - A) - Ky --t,’ P(s,-A) ’where P is the hydrostatic pressure in cm. of water as measured ins t an ditr disa ti on :or t s - x H - K y / st;s0-x P ’ *- _____where the small correction A is omitted from the surface-tensionfactor.It is to be noted that! no kinetic energy correction is to beapplied in calculating the results of experiments with viscometersin which the capillary opens into a reservoir of the same liquid.The correction calculated by earlier observers (Hagenbach, Pogg.Ann., 1860, 109, 385 ; Finkener, see Gartenmeister, Zeitsch.physikaJ.Chem., 1891, 6, 524) is only applicable when the liquidflows from the capillary directly into the air. I n viscometers ofOstwald type, however, the gain of kinetic energy at the beginningof the capillary is balanced by a lms of kinetic energy on emergingfrom the capillary into the lower bulb. The net increase of kineticenergy is therefore negligible, especially in viscometers of the slow-flow type described in the foregoing. Griineisen has shown tha2014 APPLEBEY: THE VISCOSlTY OF SALT SOLUTIONS.the introduction of such st correction into the pt values instandardising a good tube entirely destroys the regularity of theresults.I have therefore followed his practice, and omitted anycorrection for kinetic energy.The times of flow for water in the viscometers used are given inthe following table :TABLE 111.-Timss o f j o w for water (in aeconds).Time of flow T h e of flow Time of flowViscometer. at 25-01". at 18". at 00.4 1023-a 1207'7 2053'8R 800'2 943'5 1604-4703'6 830.3 1411'6 S- 6013'9 A3 - 7381'1--The slow tubes A and B were only used for very dilute solutions.Since the Griineisen correction for these determinations would haveFIG. 5.been negligible, these tubes were not standardised. The viscositydeterminations are given in tables IV, V, and VI.The viscositiesof the solutions at 18O are calculated from the equation developedabove.The surface tensions are interpolated from the values oAPPLEBEY : THE VISCOSITY OF SALT SOLUTIONS. 2015Gradenwitz (Diss. Breslau, 1902) and Piepenstock (Diss. Munich,1908). These determinations were unfortunately only carried outat 18O. The introduction of the surface-tension correction into theresults at 25*01° and Oo has therefore been impossible. At thesetemperatures the relative viscosities are calculated by the simpleformulaFor the purpose of comparison, the uncorrected viscosities at 1 8 Oare included in table V.PIG. 6.11/90 - 1 ~ _ _rn0-160'140'120 -100-160'140'120.100 '081 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 410 x Jconcentmtion.The viscosities of the more dilute solutions at 18O are plotted inFig.5, while the molecular viscosity increments at the three tem-peratures are given by Fig. 6. Fig. 6 also contains Gruneisen'svalues at 1 8 O and the curve given by his equation:______ q'%-l - - A a + B ( l -a)+Cm.r2016 APPLEBEY: THE VISCOSITY OF SALT SOLUTIONS.TABLE IV.Viscosities at 25*01°.ViscosityRelative viscosity Meail incrementD?,f"J" Uonceiitratioii visco- (s - ~ ) t relative q/vo - 1S. v2. 10rnl. meter. q/qo=(gx viscosity. Pn0'149 ~:~~~~~ 0.0174 2 '59 4 1 -00265 *Oo2'S 1.00255s 1-004C54 1 -00395R 1.006750'99824 3'10 R 1 '00395 1'0040 0.133 0 '99827 0'02990 -99933 3 3 4 X 1 *0068 1'0067 0.1190-99934 0'0567 4 1.00661 '00038 0*0825 S 1 *0097S 1 '009851 *00035 4.355 4 1 *01005 1 -0099 0.120R 1 *02641.00642 6.155 S 1.0266 1 -0267 0'11451 *00642 0'2333 4 1.02711.0356 1.01008 1.01008 0-3238 6.867 $ .03525 1.0354 0-10951.0405 0'1111 1 'C402 ::::::: 0'3643 7.142 1'040810597 1,01884 8'136 1.0598 1.05975 0'1110 1'01882 0'53851.0979 1,09805 1*0080 0'1131 1-03240 0.8666 9'5334 1.1117 1.036561.03660 0'9663 B 1'11049 '886 S 1.11145 1'1112 0.11511 '1 567 0'1191S 1.31515 1.3151 0-13873.8541 15.678 1-74075 0'19221*20848 4,578 16.60 4 2-0577 2.0577 0'23101'208331'283441'28340 5?3491'15671'15671.05134~:~~~~~ 2'2719 13'14G 1.315110.96 1'05146 S3.0255 0'346 B 3.0274 3-024 18-0APPLEBEY: THE VISCOSITY OF SALT SOLUTIOKS. 2017303% RTABLE V.42u,I19% n8 w ..A h*ib[Soh tionmadeup 0'00724by1veight.J1.93 0.99392 1.0004 $ iii;;;; 1*00124 1.0C125 0.172A 1*00200 0.997600.99759 0.0131 2.36 ~:~~~~~ 1.0007 1.00199 1002GO 1.00201 0'1530.99758S 1'00470.99858 o.99858 0.0379 3-36 1.00016 1.0014 f i::::; 1.0047 1'0047 0.124A 1.004694 1.00905H 1'00921'00019 1.00022 0-0784 4-28 ::::::: 1-0023 S 1.0089 1,00905 1.0090 0'1155.25 1.004521.00453 1.0036 2, ~:~~~~ 1,01545 1.01535 0.1061*002851.00285 0*1446 ::;:;;: 0.2653 6-43 1.00951 1*0061 ::g:i 1.0278 1.0276 0.1041.02563 1.03562 0 7034 8'59 i : ~ ~ ~ ~ ~ 1.0151 4 1.0737 1.0737 1'0731 0.10391,05001 1.05003 1'283 10.87 1.05245 1.0273 S 1.1441 1.1438 1.14395 1.1429 0.11134 1.1697R 1.16991.05811 1.05806 1.471 11.37 ::::::; 1'0313 S' 1.17015 1-1699 1.16565 0.114713.62 1.10818 S 1.349713 .66 1 *lo9591.10812 1.0508 R.1.34985 1 3172 0.1373 1.104981.10498 2'5281.10956 1.0512 R 1.3579 1.3579 1'3552 0.1393 1'106441'10643 2'5501.133411'13342 3.120 14.61 1.13685 1.0618 11 1'4906 1.4906 1'48695 0,15611.133431.14a75 1.0648 Iz 1.53685 1.5367 1.5327 0'1624 1.141221.14120 3*279i:;;;: 4.363 16'34 ''*Oo8 1.2010 1'0812 i::::: 1-9346 1.9274 0-2125S 1.35794 1,3579514.86 1.14475 4 1.5362018 APPLEBEP : THE VISCOSITY OF SALT SOTJUTIONS.TABLE VI.Viscosities at 00.Viscosityincre-Xean mentrelative q/qo - 1viscosity.RelativeviscosityVisco- 9 -(s - h)tD'$ meter.~ o - ( ~ o h ) f , 'Concen-trationDF"Jln m.[Solutionmade up 0.0401by weight]loin,,3 '42 1'0032 0'0801 -000391.00038 0'0833 4 '37 1'0058 0.070[Soh tionmade tip 0.1026by weight]1.00447 R 1.00771-00449 4 1.00755 4 '68 1.0076 0.0741-00990 I; 1.01561.00990 4 1 *0153 6-12 1.01545 0.06751.018181.0181 51.018174S4R4R4SRIz5'444A'4-8SRS41'02781.02791.027751.02781 -03241 *032551'03261.06161.06161'08731.087751.13441'13461,13441.20671 *206751.20661.27681.27711.27701.08751.013911 *01389 0'4279 7 '48 1'0278 0.06657.849-5010.401.02099 1-0325 0.06751 '03775 1.0616 0.07181.043641.043681.050211 '05019 1'0875 0.07721-070401.07036 11'63 1'1345 0'08551.085781.08583 2.0991-0857812.80 1.09505 1 2067 0.09841.114661 '1 14531.1 14661.104511.10451 2'508 13.59 1.2770 0'1104Discussion of' Results.-The viscosities determined at 18O agreevery satisfactorily with those obtained by Gruneisen.The valuesobtained for the most dilute solutions, however, differ considerablyfrom those calculated from the formula proposed by him. Thecourse of the curve given by Gruneisen's equation :d?!d = Ba+R(l -a)+Cm171is shown by the dotted line in Fig. 6. When m=0, that is, atinfinite dilution, a= 1 and k1 = A . The increment curve oughtAPPLEBEY : THE VISCOSITY OF SALT SOLUTIONS. 2019therefore to cut the axis of ordinates at a distance A from theorigin. The actualcourse of the increment curve is, however, quite different.Thevalues obtained in the most dilute solut,ions are already muchgreater than this value, and the curve is still rising.It may be noted that the most dilute point obtained by Gruneisenhimself also lies considerably higher than the value calculated fromhis equation. Nor is this an isolated case. Out of ten saltsinvestigated by him at sufficiently great dilut,ion, in eight the mostdilute solutions give values too high for his equation. The deter-The value of A given by Griineisen is 0015868.mination of k1 for these dilute solutions involves a very largemexperimental error, as has been indicated by the size of the circlesround the determined points in Fig. 6. The general nature of thephenomenon nevertheless precludes the view that these high valuesare due to errors of determination, for, if that were the case, thedeterminations should be equally distributed above and below thecalculated curve.These considerations, together with the determinations at greaterdilutions than Gruneisen's, show that, although his equation repre-sents the facts over it certain range, it is not valid for allconcentrations.Gruneisen's equation contains the assumption that the effects ofion and undissociated salt respectively are distinct and separable,and that each is in all cases proportional to the concentration ofthe component considered.The second assumption can only be trueif the process of solution is simply a mechanical mixing.There is general agreement among physical chemists that theprocess of ionisation in electrolytes is accompanied by combinationbetween the ions and the water molecules.Since water is a highlyassociated substance and consists of a mixture of simple andpolyrnerised molecules, the extraction of water molecules from thesystem by the ions of the salt must be accompanied by a readjust-ment of the water equilibrium, polymerised molecules breakingdown in order to restore the equilibrium. The effect of the ionson the viscosity of the system is therefore twofold: (1) the simplemixture effect, increasing the viscosity by remon of the great sizeof the hydrated ions; (2) the effect on the water equilibrium."* It should be noted that the effect of the salt on the water equilibrium does notinvolve a change in the equilibrium constant, but is simply a dilution effect similarto that observed by Dixon and Peterkin on diluting nitrogen peroxide ~ i t h an inertgas (Trans., 1899, 75, 613).Thus, if the concentrations of simple and polymerisedmolecules in pure water be c1 and c,, and the addition of an ionised substance lead tothe extraction of x simple molecules of water, the concentrations of simple and poly2020 APPLEBEY : TIiE VISCOSITY OF SALT SOLUTIONS.The disappearance of the maximum density phenomenon whensalts are dissolved in water shows that the effect on the waterequilibrium is a depolymerisation. This effect will therefore leadto a diminution of viscosity. The diminution will not, however,depend alone on the concentration of the ions, but also onthe amount of polymeride present.The effect will thus slowlydecrease with successive additions of salt.Another factor of which we must not lose sight is the changein size of the solvent envelope round the ion, the amount of watercombined with each ion becoming greater on dilution.I n the following pages an attempt has been made to deduce atheoretical connexion between the viscosity of a solution and themolecular and ionic phenomena involved in its formation.It has been tacitly assumed in the above that viscosity is a directfunction of molecular size. The general validity of this relation isestablished by the following facts :(1) Liquids which are known to be highly associated have usuallyalso a high viscosity.Propyl alcohol .................. 2.25 0.0223The following examples may be cited:Association Factor.* Viscosity a t 2 O O .iisoPropyl alcohol ............... 2.86 0.0243up-Dihydroxypropane ......... (large) 0.4479Glycerol ........................... (very large) 10.69 (at 18'28"),+Ethyl alcohol ..................... 2-74Ethyl acetate ..................... 0.99Ethyl ether .................... 0.99Acetic acid ........................ 3'620.01 2020.012320.004510.00237* Ramsay and Shields, Trans., 1893, 63, 1089.-f Gartenmeister, Zeitsch. physikal. Cham., 1891, 6, 524.2 0. G. Jones, Phil. Mag., 1894, [v], 37, 451.(2) The work of Heydweiller (TVied. Ann., 1895, 59, 193) onthe viscosity of liquids a t high temperatures.The viscosity ofwater diminishes much more rapidly than that of unassociatedliquids when the temperature is raised from Oo to 50°. Above 50°,when the association is small, the rate of diminution is approximatelythe same as that of unassociated liquids.merised molecules in the solution will be c ' ~ and c'~, where (neglecting the change ofvolume on solution)c1 f nc, = C ' ~ + m',, + x,c,n -c' and -- -1 =k,cn c'nfrom which it follows that, siiice x is a positive quantity,or that the extraction of siniple molecules by the salt leads to a diminution in theassociation of the water remainingAPPLEBEY : THE VISCOSITY OF SALT SOLUTIONS. 2021(3) The effect of pressure on the viscosity of water (Cohn, Ivied.Ann., 1892, 45, 666). An increase of pressure always brings aboutan increase in viscosity in the case of non-associated liquids.At lowtemperatures the viscosity of water, however, first diminishes withincrease of pressure, reaches a minimum value, and then rises inthe normal manner. Since the association of water is accompaniedby an increase of volume, as is shown by the maximum densityphenomenon, the effect of pressure must be to break down theassociated molecules. The marked diminution in viscosity, whichis superimposed on, and in the initial stages entirely masks, thenormal effect of pressure, can only be occasioned by this diminutionin molecular size.(4) The effect of different ions on the viscosity of water is in thereverse order of their mobilities, for example :Viscosity of Mohilityflalt.N/lO-solution a t 18". of cation.* Lithium nitrate ............... 1.0113 42'6t SOdlUln ,, ............... 1.0044 22.62 Cesium ,, ............... 0.9933 T8.S* Applebey. .i- Gruiieisen, Zoc. cit.2 Unpublished result kiiidly comniunicated by Mr. T. R. Merton.t Potassium ,, ............... 0.9941 7 5 . 5There is much evidence to show that ions of small mobility areheavily loaded with water molecules, and are thus larger than themore mobile ions.Since the ions in a salt solution are enclosed in a water envelope,it is probably justifiable to neglect the specific chemical differencebetween hydrated ion and water-molecule, and to assume a rigidconnexion between mean molecular volume and viscosity. As thesimplest assumption, it has been supposed that these quantities aredirectly proportional.*The different molecular species present in a salt solution are:(a) Simple water molecules, H,O;( b ) associated water molecules, assumed to be triple, (H20)3;( c ) ions, hydrated to an unknown extent, Li+ +xH,O, NO,- + yH,O;(d) undissociated molecules, possibly combined with water,(e) in strong solutions salt complexes, (LiNO&.The two kinds of water molecule are in kinetic equilibrium withone another.Their proportions in pure water can be obtainedfrom the association constant in the following manner :LiNO, ;* Dunstan and Thole have shown that these quantities are approsimatrlyproportional for different organic liquids which are not associated (Procr, 1907, 23,19)2022 APPLEBEY : THE VISCOSITY OF SALT SOLUTIONS.Let a be the association factor for water at 1 8 O .c1 ,, ,, concentration of single molecules H20 in gram-c3 ,, ,, concentration of triple molecules (H,O), in gram-molecules per litre.molecules per litre.Then 3 C , + C l = [I,c3 + c1and 54c, + 18c, = lOOOs, where s is the density of water.Then a -1 (3 -a)c3::(a- l)q, or c3= cz- , 3 - aand 5 4 ( r c ) c l + 18c, = 1 0008,3 - a1000s(3-a) and cQ= loo08 (a-1)36a 'whence c1 =36aNow for the equilibrium (H20)3 3H@we havewhenceTaking a t 18O Ramsay's value of 1.65 for the association constant(Zeitsch.p h y s i k d Chem., 1895, 15, 106) and 0.99863 as the density,The value of k thus found can be used to calculate the effect ofTaking a solution of weight normality m, density s, and degreeE = 0*0009347.the salt on the water equilibrium.of ionisation a,1000 C.C.of the solution weigh 1000s grams.Of this the salt accounts for Mms grams (where M=molecularweight of the salt), leaving (1000 - Mms) grams of water.Now, i f w be the average hydration number for the two ions,that is, if 1 gram-molecule of the salt, completely ionised, combineswith 2w molecules of water, the amount of water thus removedfrom the system is :2masw x 18 grams.The free water is therefore reduced to:(1000 - Mm - 36maw)s grams.Letting c1 and c3 as before represent the concentration of singleand triple molecules, we have:or, since c3=k x c13,54c3+ 18c, = (1000 - M m - 36maw)s,5411.~~3 + 18c, = (1000 - M m - 36maw)sAPPLEBEY : THE VISCOSITY OF SALT SOLUTIONS. 2023froin which c1 and c3 can be obtained (most conveniently by trial).The total number of gram-molecules in a litre of solution is:c l + c 3 + m ( l + a ) .The mean molecular volume is therefore :1000C,C3 + ms( 1 + a)’The mean molecular volume in pure water is:1000where cI1 and cl3 are the concentrations of single and triplemolecules in pure water.On the assumption that viscosity is proportional to meanmolecular volume, we have therefore :+ CIS’7 - ctl + ctg - - __yo c1 + CQ + m2s(l +a)’Owing to the absence of accurate determinations of several ofthe quantities involved in this treatment, and especially of thehydration numbers at different concentrations, it is at presentimpossible to submit the equation to it quantitative test.It may,however, be noted that the course of the calculated viscosityincrement curve corresponding with the equation agrees with theactual form observed in on0 important respect. The calculatedcurve shows the phenomenon of a minimum increment at about0.5 normal, as does the observed curve. As an illustration of thisthere has been included in Fig. 6 a curve representing the viscosityincrement calculated on the assumption that the hydration of theions is constant and equal to 6.3 molecules of water per ion. Thecurve has been calculated with Ramsay’s value for the associationof water a t 1 8 O , and with values of a obtained from Kohlrauschand Maltby’s conductivity determinations (Sitzungs b er.K . A kad.Wiss. Berlin, 1899, 655) by means of the relation:where X = molecular conductivity, and A, = molecular conductivity a tinfinite dilution.The calculated curve differs considerably from the observed,although they are of the same general shape. A very inconsiderablechange in hydration is, however, sufficient to bring the curves intoharmony. The ~ a l u e s of the hydration necessary have been foundby trial, and are collected in the following table2024 APPLEBEY : THE VISC081TT OF SALT SOLUTIONS.No: xiality.0’007240.01310.03790’07840’14460’26530.70341.0Hydration calculated fromviscosity in gram-moleculesof water per gram-moleculeof ion.8 -07.56.56.36 *16.16.056-05These values are in good agreement with those obtained by othermethods for various salts.For lithium nitrate itself Wymper(Proc. Roy. SOC., 1907, 79, 576) obtained a value of 13 for thehydration of a molecule of the salt in a normal solution (from the“ neutral salt effect ” in the inversion of sucrose). For potassiumchloride in normal solution, Philip (Trans. Furaduy SOC., 1907, 3,145) gives 9.4, and Caldwell (Proc. Roy. SOC., 1906, 78, 290) 11molecules of water per molecule of salt, whilst for more dilutesolutions Bousfield (Proc. Roy. SOC., 1904, 76, 563) gives 12. I naccordance with its smaller mobility, the lithium ion seems to berather more hydrated than the potassium ion.From the results obtained a t 25*01°, the same method ofcalculation giSes values for the hydration numbers about 0.3 higherthan those obtained at 18O.A similar small increase of hydrationwith temperature is indicated by the conductivity values of manysalts (Noyes, see Washburn, Tech. Quart., 1908, 21, 425).Hydration inSalt. Normality. niols. per ion.For other salts, Griineisen’s values at 1 8 O give:Sodium nitrate ... .. . , , . 0.1 3.40.05 3.5Lithium chloride . , , , , , 0.1 8 *8Salts which are less hydrated than these, however, give impossiblevalues. Thus, potassium nitrate gives small, and czsium nitratelarger, negative values. In view of these negative values, it maybe recalled that Rennie, Higgin and Cooke (Trans., 1908, 93, 1162)found that czsium nitrate diminished the rate of solution of copperin nitric acid, whilst sodium nitrate and lithium nitrate greatlyaccelerated the action.To sum up, this method of calculating the hydration, like themethods depending on the concentrating effect of neutral salts inchemical reactions, gives values approximating to the truth forsubstances which are much hydrated, but gives values too lowfor less hydrated substances. It is not improbable that the failureof all these methods of calculation in this respect depends on somehitherto unconsidered factor in the equilibrium of salt solutionRUHEMANN : TRIKETOHYDRINDENE HYDRATE. 2025which becomes of increasing importance as the hydrationdiminishes.Summary.-1. It has been found possible to construct visco-meters in which the flow of liquid is so slow that, for solutions whoseviscosity differs 'little from that of water, Poiseuille's law is obeyedwith an error of not more than one part in 10,000. The methodsused in testing the viscometers are described.2. A correction has been introduced for the variation in surfaceeffects when different liquids are used in the viscometer.3. Determinations of density and viscosity have been carried outwith lithium nitrate solutions at Oo, 1 8 O , and 2 5 O over a large rangeof concentration.4. The formuIa of Griineisen is found not to represent thephenomena of dilute solution.5. A method of calculating the viscosity of salt solutions fromtheir hydration numbers, or vice versa, has been described. Theapplication of this method to the viscosities of lithium nitratesolutions at 18O gives results consistent with the estimates of ionichydration made by other observers.6. The application of tho methcct to other salts is discussed.I am greatly indebted to Mr. D. H. Nagel and Mr. H. B. Hartlegfor much valuable advice and enccuragement during the progressof this work.pH TSICAL CHEMIS'I'RY LABORATOI~Y,~ ~ A L L I u L AND TILINITY COLLEGES,OXFORD

ISSN:0368-1645    

DOI:10.1039/CT9109702000

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

RUHEMANN : TRIKETOHYDRINDENE HYDRATE. 2025CCXII. -Triketohydrz'nderie Hydmite.By SIEGFRIED RUHEJIANN.IN a recent paper (this vol., p. 1438) it was shown that the condensa-tion product of a-hydrindone with p-nitrosodimethylaniline, on treatmentwith dilute sulphuric acid, decomposes with the formation of trike'to-hydrindene hydrate. Its formula was represented thus :according to which the elements of water are united with the %ketonicgroup of triketohydrindene. There cannot be any doubt as to thecorrectness of this formula, because the union of water with anyother ketonic group of the triketone would produce a colouredVOL. XCVII. 6 2026 RUHEMANN : TRIKETOHYDRINDENE HYDRATE.mmpound owing to the proximity of two ketonic groups, whereastriketohydrindene hydrate is colourless, as is also 1 : 3-cliketo-CO hydrindene, C6H,<CO>CH,. Further evidence in support of theabove formula is the fact that the hydrate, on treatment withphosphorus pentachloride, is transformed into the colourless 2 : 2-di-chloro-1 : 3-diketohydrindene, C6H,<CO>CC12.CO Triketohydrindenealso forms additive products with other substances, such as guanidineor benzamidine, which are colourless, and therefore are to be repre-sented by formuls similar to that of triketohydrindene hydrate.The hydrate further reacts with hydrogen cyanide t3 yield theunstable cyanohydrin, C,H,<CO>C(OH)*CN. COA closer study of the remarkable behaviour of potassium hydroxidetowards the hydrate which was described previously (loc.cit., p. 1448)led t o the following result. The reaction proceeds in three distinctphases, which are indicated by colour changes. On the addition ofthe alkali to the crystals OF the hydrate, they turn yellow and thendissolve to form a yellow solution; this subsequently becomes blue,even at the ordinary temperature, if the alkali is concentrated. Theblue colour, bowever, is very fugitive, and disappears on dilution withwater t o yield a colourless solution. On using dilute potassiumhydroxide (about 15 per cent.), the blue colour does not appear unlessthe temperature is raised immediately after the addition of the alkalit o the hydrate. The colourless alkaline solution, which represents thelast phase of the reaction, contains the potassium salt of o-carboxy-mandelic acid, CO,H*C,H,*CH(OH)*CO,H, because, on treatment withdilute sulphuric acid, it yields phthalidecarboxylic acid,The formation of this acid leads t o the conclusion that, under theinfluence of the alkali, the five-carbon ring of triketohydrindeneruptures with the formation of phenylglyoxal-o-carboxylic acid,CO,H*CBH,*CO*CHO, which finally undergoes the change to phthalide-carboxylic acid.This behaviour resembles in every respect thechange which, by the action of alkalis, phenylglyoxal undergoes t omandelic acid :C6H5*CO*CH0 -+ C6H5*CH(OH)*C0,H.The result arrived at in examining the behaviour of triketohydrin-dene hydrate towards potassium hydroxide supports the view whichwas expressed before (Zoc. tit.) concerning the product of the action ofammonia on the triketone.The formation of phenylglyoxal-o-carboxylicacid is to be regarded as the first change of the triketonic compounRUHEMANN : TKIKETOHYDRINDENE HYDRATE. 2027which is produced by the alkali, and this view follows, also, from thefact that the yellow alkaline liquor reduces Fehling’s solution.The explanation of the intermediate phase of the reaction which ischaracterised by the blue colour of the alkaline solution is difficult,because the solution readily loses its colour, and passes into the finalphase of the reaction, It is, therefore, only from analogy to thechanges which the diketopyrrolines and the compounds with similarstructure undergo, on treatment with alkalis, that a view can beexpressed concerning the nature of the blue product.The bluesolution which, for example, diketodiphenylpyrroline yields withpotassium hydroxide was explained (Trans., 1909, 95, 984) by thechange into its tautomeric form :$!Ph---CO CPh = ?*OHCPh-NH.60 -+ bPh:N*CO ’which contains a phenolic group and has an o-quinonoid structure,A similar arrangement may be assumed to exist in the potassiumcompound which is formed in the second phase of the action of thea1 kali on t r iketo hydrindene hydrate. Accordingly, pheny lglyoxal-o-carboxylic acid, which is first produced, undergoes ring formation,thus :in which, also, phenolic groups are associated with an o-quinonoidstructure. A substance with this constitution may be supposed t oyield blue salts with alkalis.These, like the corresponding saltsof the diketopyrrolines, are unstable, and, on dilution with water,are transformed into the salts of o-carboxymandelic acid :The further study of triketohydrindene hydrate led to results whichappear to be of great interest. It was found that a deep blue colouris produced on warming a mixture of aqueous solutions of this com-pound and an aliphatic or an aliphatic-aromatic amino-acid whichcontains the amino-group in the side-chain. As shown below, thisreaction has been successfully applied to a number of a-amino-acids,but a8 yet only two P-amino-acids have been tested, and they werefound to differ markedly from the a-amino-acids in their behaviourtowards the triketone, because with them the colour reaction takesplace less readily, and in the case of p-amino-P-phenylpropionic acid isfar less intense than with the corresponding a-amino-acids.No6 ~ 2028 RUEEMANN : TRIKETOHYDRINDENE HYDRATE.coloration, however, is produced by the triketone in solutions ofaromatic amino-acids which contrain the amino-group in the nucleus,nor does it occur with substituted amino-acids, such as phenylglycineor hippuric acid. On the other hand, triketohydrindene hydrate givesa blue reaction with peptone, and this fact in the. light of the resultsindicated above leads to the conclusion that in the peptones, compoundsoccur which contain the free amino-group of amino-acids.The same coloration is produced i n normal human urine on warmingit with a n aqueous solution of the reagent.This behaviour agrees withthe observations of Abderhalden and Pregl (Zeitsch. pAysio2. Chem., 1905,46, 19 ; see also Abderhalden and Schittenhelm, ibiu?., 1906, 47, 1396),according to which the urine contains a protein-like substance. Theauthors showed that it does not contain free amino-acids, but that theseare formed from it on hydrolysis.EXPERIMENTAL.Triketohydrindene hydrate was prepared in the manner describedbefore (Zoc. cit.) by warming slightly the product of the action ofp-nitrosodimethylaniline and a-hydrindone with dilute sulphuric acid ;its extraction from the dark solution which is formed, is more con-veniently effected by ethyl acetata than by ether on account of itsgreater solubility in that boloent.Additive Product of ~r&tohydr~ndene with Guunidinc,c,B~~~~>c(oH).NH.c(:NH).NH,.This is formed by adding triketohydrindene hydrate (1 gram), dis-solved in water, to an aqueous solution of guanidine, obtained from itschloride (0.6 gram) and the calculated quantity of potassium hydroxide.The mixture turns red and soon deposits a colourless solid, whichis insoluble in water, alcohol or benzene; it does not melt, butbegins to darken at about 190" and finally becomes black :0,2015 gave 0,4045 CO, and 0.0740 H20.0.1945 ,, 32.6 C.C.N, at 30' and 754.5 mm. N= 19 02.C1,H90,N, requires C = 54.79 ; H = 4.1 1 ; N = 19.18 per cent.On heating hhe compound with water for some time, slight decom-position takes place, and a small quantity dissolves to yield a redsolution.C-54.75; H=4.08RUHEMASN : TRIKETOHYDRINDENE HYDRATE.2029Additive Product of Tviketohydrindene with Benxamidine,This is prepared in a similar way to the former substance, namely,by adding sodium carbonate to the mixture of triketohydrindenehydrate (1.2 grams) and benzaxnidine hydrochloride (1 gram) dissolvedin hot water. A white solid is soon precipitated, which is insolublein water; it is sparingly soluble in boiling alcohol, but does notseparate from the solution without the addition of water, whencolourless prisms are formed, which darken at about 200" and decomposea t 229-230' with evolution of gas :0.2011 gave 0.5050 CO, and 0.0805 H,O.0.2051 ,, 17.8 C.C. N, a t 17" and 762 mm. N = 10.10.This snbstance is insoluble in sodium carbonate ; it is decomposed byC = 68.49 ; H = 4.44.C,,H,,0,N2 requires C = 68.58 ; H = 4-29 ; N = 10.0 per cent.hot potassium hydroxide with the formation of benzaldehyde.Additive Product of Friketohydrindene with Hydrogen Cyanide,Whilst the additive compounds mentioned above are fairly stable, thecyanohydrin, which triketohydrindene hydrate forms with hydrogencyanide, is readily decomposed.X t is obtained by mixing the triketonehydrate (0.5 gram), dissolved in water, with potassium cyanide(0.5 gram), and then adding dilute hydrochloric acid to the deep redeolution which is produced, The colour disappears and pale brownneedles separate which sinter and darken at about 120°, and at 148'melt with evolution of gas.The compound dissolves in boiling water,but at the same time decomposes. For analysis, the crystals formedi n the reaction were mashed with cold water and dried in a vacuumdesiccator over sulphuric acid :0.2053 gave 13.8 C.C. N, at 1 8 O and 749 mm. N = 7.64.C1,1J50,N requires N = 7.49 per cent,Aciiolz of Pho~phorus Pentach loride on TTiketoh ydrindene Bydrate.On mixing the triketone hydrate (1 mol.) with phosphorus penta-chloride (2 mols.), no reaction ta.kes place at the ordinary temperature;at loo", the mixture evolves hydrogen chloride and assumes a redcolour, which is probably due to the removal of water and the formationof triketohydrindene. The action proceeds more readily if phosphorylchloride is used together with phosphorus pentachloride ; on warming2030 RUHEMANN : TRIKETOHYDRINDENE HYDRATE.the whole dissolves t o yield a yellow solution, which is cooled andthen poured on ice, when an oil is precipitated which soon solidifies.The solid is washed with light petroleum, which removes a yollowproduct, whilst a colourless substiance remains undissolved.Thisis readily soluble in hot dilute alcohol, and, on cooling, crystallises i ncolourless plates. The yield is poor owing to the formation of theyellow by-product, The compound mas identified as 2 : 2-dichloro-l : 3-di-ketohydrindeno, C,H,<CO>CC12, co by the melting point, 124-1 25O,and its chemical bebaviour (compare Zincke and Gerland, Ber., 1858,21, 2390).Fmmation of Phthalidmarboxylic Acid from Triketohydrindene Eydrate.The action of potassium hydroxide on the triketone hydrate wasdescribed in a previous paper (this vol., p.1448) and more fullyon p. 2026. It was stated that the final phase of the reaction yieldsa colourless solution. This, when treated with an excess of dilutesulphuric acid and digested on the water-bath for an hour, containsphthalidecarboxylic acid, yo' '>CH*CO,H. It is isolated from theC,H,acid solution by extraction with ether, and, on evaporation of theether, is left as a white solid. This readily dissolves in hot water, and,on cooling, crystallises in colourless plates melting at 150-151°, Theyield is almost theoretical. (Found : C = 60.70 ; H = 3-37, Calc.,C = 60.67 ; H = 3.37 per cent.)The compound is identical with the acid which Zincke (Bey., 1894,27, 743), in the course of his researches on the action of bleachingpowder on quinones, obtained from monochloro-P-naphthaquinoneas well as from ~eocoumar~ncarboxylic acid.Action.of 'I.iketoh~dl.i~enehydrate on Amino-acids.On mixing a slightly warmed aqueous solution of triketobydrindenehydrate and glycine, an intense blue colour develops immediately, and,after a short time, a dark solid separates. The same behaviour isshown by all the a-amino-acids which 1 have been able to obtain;several of them I owe to the kindness of Dr. Hopkins, whomI have also to thank for the interest he took in the progress ofthe work. The reaction has been applied to alanine, valine,leucine, tyrosine, to a-amino-/I-phenylpropionic, aspartic, and glutamicacids, to tryptophan and cystine, Owing to the fact that thelatter compound is sparingly soluble in water, it must be boiledwith a solution of tbe triketone hydrate; in all the other caseRUHEMANN : TRIKETOHYDRINDENE HYDRATE. 2031the reaction takes place almost with the same rapidity as with glycine,and requires mere traces of the reagents, The sensitiveness of thereagent is indicated by the fact that the blue colour is still per-ceptible on slightly warming glycine with a solution which contains1 part of triketohydrindene hydrate dissolved in 15,000 parts ofwater.In the same dilution, the reagent yields with ammonia B yellowcoloration, whereaq the colour is red, or reddish-violet, on using moreconcentrated solut'ions (compare this vol., p. 1447).The shade of theblue coloration that is produced shows but slight variations with thedifferent a-amino-acids. Of the P-amino-acids only two have beentested, namely, P-aminopropionic acid and /3-amino-P-phenylpropionicacid. The latter, which was prepared according to Posner's directions(Bey., 1903, 36, 4313) by the action of hydroxylaruine on cinnamicacid, differs remarkably from its isomeride, a-amino-/3-phenylpropionicacid, in its behaviour towards triketohydrindene hydrate ; no colouris produced on mixing the reagents dissolved in hot water, A faintviolet coloration, however, develops if the solution is boiled for sometime ; on the other hand, the corresponding a-amino-acid readily reactswith the triketonic compound to yield a deep blue colour. Thedifference between a- and P-aminopropionic acids in their behaviourtowards the reagent, although not so striking as with the formerisomeric acids, is yet apparent, especially as regards the rapidity ofthe reaction, which in this case, also, is greater with the a-amino-acid.It is, however, necessary t o examine a larger number of the @amino-acids before, by means of the reagent, a general distinction betweenthe two groups of amino-acids can be established, Neither phenyl-aminoncetic acid (phenylglycine) nor hippuric acid yield a colorationwith the triketone hydrate, even on boiling the aqueous solutions ofthe mixtures, and this result indicates that the reaction depends onthe amino-group of the amino-acid being intact. Aromatic amino-acids which contain the amino-group in the nucleus, for example,o-aminobenzoic acid, also do not respond to the test.The chemical nature of the colour reaction has not yet beenascertained, but experiments in this direction are already in progress,and will be recorded shortly.UNIVERSITY CHEMICAL LABORATORY,CAMBRIDGE

ISSN:0368-1645    

DOI:10.1039/CT9109702025

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

2032 PRIDEAUX : THE VAPOUR PRESSURES AND MOLECULARCCX I I I. -The Vapour P m w u r e s and MolecularVolumes of the Mercuric Halides and the Rela-tions between Atomic Volumes of Elements Beforeand After Combination.By EDMUND BRYDGES RUDHALL PRIDEAUX.THE present investigation has the aim of comparing the volumes ofliquid elements with those of their liquid compounds. As com-parison temperatures the boiling points under atmospheric or otherequal pressures have been retained. The results of Young andothers show that at vapour pressures below one atmosphere it is amatter of indifference whether equal pressures or correspondingpressures are chosen for the above comparison. The procedure offinding atomic volumes at the boiling point is too well known toneed description, It has been departed from in several particulars.(1) No attempt has been made to tabulate difference of molecularvolume, the ratios only being compared.(2) No experimentally inaccessible atomic volumes, such as thoseof carbon and hydrogen, have entered into the calculation.(3) The effect of structure on the molecular volume has beenas far as possible eliminated by considering only simple compounds,in which there is not more than one multivalent element.The term atomic or molecular volume at any pressure is usedthroughout to denote the total volume occupied by the gram-atomor gram-molecule liquid at such a temperature that its,vapourpressure is that specified. Under these conditions the ratio betweenthe specific volumes at, for example, 760 and 200 mm.pressure isa constant for liquids which are not associated or dissociated.For example, -___- v‘‘760) is for C6E6 1.050, PC1, 1,050,VD4 2 w ’ )C,H,Br2 1.048, 0, 1.048, HC1 1.049. Instances could be multiplied.Associated and monatomic liquids : H,O 1.030, CH,*CO,H 1,041,Hg 1.012, A 1.014 (760-400), the normal value for this pressureinterval being 1.028.These relations may be connected in the following way wit.htheories involving the conception of (‘ co-volume.” The term isused throughout as generally to mean the volume through whichthe molecules have motion relatively to one another, sometimescalled “ free ether,” it5 distinguished from the “ bound ether ” orinteratomic space, which, together with the volumes of the atomsthemselves, makes up the (‘ b ” of van der Waals’ equation(Clausius) which no other atom can penetrateVOLUMES OF THE MERCURIC HALIDES.2033Now, if we imagine an ideal and normal liquid expanding fromthe condition in which the co-volume is zero (which, as will be shown,is probably not in most cases -273O), the vapour pressure willincrease at the same time, and since the pressure is a function of thetemperature and the increase of cevolume also a, function of thetemperature, the increase of cevolume may be expressed as afunction of the pressure.Thus if JTp and Vo are the volumes of liquid at “ p ” and zeropressure :4(p)Vo being therefore the co-volume at= Yo[ 1 + &)I*p.”For another liquid, also expanding between (‘ o ” and “ p ” :A t a higher pressure, p l , the volumes become Tr0[1 + +(p,)] andV:[ 1 + +’(p,)] respectively.But as shown above, in the case of normal liquids :that isTherefore + ( p ) = +‘(p) and + = +I.these liquids.to the lowest, and eventually, zera pre-sure :(1) The increase of co-volume is the same function of “ p ” for allAssuming that the same law of expansion holds down(2) The co-volumes ‘vot+(p) and Fvo+(p) at any pressure areproportional to the actual volumes of the molecules Vor and Vo.(3) The ratios between the volumes of the liquids at equal vapourpressures are equal to the ratios between the actual volumes of themolecules.As soon as the vapour becomes so dense that the specific molecularattraction begins to have an effect in that phase, the nature of therelation between increments of vapour pressure and volume willprobably change, and +(p) take another fwm.By taking this intoaccount, Mills (J. Physical Chem., 1902, 6, 209; 1904, 8, 383, 593)Q has deduced the formula -- = constant for a series of normal x- yoliquids at different temperatures- (q =inner heat of vaporisation of1 gram liquid ; d and D = densities of liquid and vapour). This equ*tion holds up to the critical temperature. It can be shown that attemperatures so low that JD may be left out of account compare2034 PRIDEAUX : THE VAPOUR PRESSURES AND MOLECULARwith 7 2 (considerabIy below the boiling point under atmosphericpressure), Mills' equation necessarily leads t o the regularity men-tioned above.For consider two liquids, A and B, at two pressures,P and P, and let Q be the total molecular latent heat of vaporisationand €2 the gas constant. To the values of P, T, Q and d for thet,wo liquids assign the symbols:P' T A Y"B Q'A Q'B d'A d ' ~P TA 25 Q" QB d~ dg.Then for each liquid, by Mills' formula:Multiply by 5!"/T' :KT' &'/T&Id';i -r . . . . . . . , . , (2).Divide equation (2) for A by (2) for B :But for normal liquids :Alsowhere " c " is very small, not greater than 0*0005 for the mostdissimilar liquids : thereforeThis relation can only be deduced from Mills' formula a t tem-peratures at which the density of the vapour may be neglected.A recalculation of the constant (Mills, J . Pltysical Chem., 1909,13, 512) has proved that the formula holds with the greatestaccuracy in this region.The assumption, then, that +(p) remains constant down t o thelowest pressure is in accordance with the above theory of molecularattraction, and with the facts of expansion down to the lowestvapour pressure at which liquid volumes have been compared.The volumes at zero pressure could be found by extrapolationif the pressures were known with sufficient accuracy.The laws ofexpansion of liquids lead to an ideal state of zero co-volume for aperfect liquid, just as the laws of expansion of gases lead to thestate of an ideal gas at the absolute zero.In the case of liquids, however, it does not seem probable thaVOLUMES OF THE MERCURIC HALIDES. 2035the zero of pressure should occur at the same temperature in eachcase. The necessity for a special zero in each case has already beenfelt in explaining the deviations from the reduced equation ofcondition (Young, Stoichiometry, p.237).I f it were possible, then, to obtain the liquid volumes of non-associated elements and compare them with the volumes of liquidnon-associated compounds all at the same pressure, the ra€ios ofthese volumes would correspond with the ratios of the actualvolumes of the molecules, the expansion or contraction on com-bination being thus discoverable.Owing, however, to the scarcity of data, a direct comparison ofthis sort is in few cases possible, and where it can be made, mostof the expansions are found t o be not quite normal, The degreeto which these irregularities influence the ratios will appear fromthe experimental data.EXPERIMENTAL.Materials.-The mercuric chloride was resublimed in a current ofdry chlorine.Several analyses were made both of the freshlyprepared salt and that which had been boiled for some time in theair, or heated in the dilatometer. The mercury was determined asmercuric sulphide, and the chlorine as silver chloride, and theresults were satisfactory.The mercuric bromide prepared to arder by Hopkin and Williamsgave satisfactory results on analysis, and was employed withoutfurther treatment in some cases. A sample redistilled with a littlebromine gave identical results on analysis and in the dilatometer.The mercuric iodide was also Hopkin and Williams’ preparation.It was analysed by electrodeposition on a silver-plated platinumbasin cathode, and gave theoretical results.It was afterwards re-distilled to remove traces of a non-volatile impurity, whichapparently did not affect the analysis, but made the liquid surfacedifficult to locate in the dilatometer.DiZatometers.-These were of fused silica, and were supplied bythe Silica Syndicate. They were graduated as required by a,diamond fixed in place of the needle on a, divider, and calibratedwith mercury in the usual way. The bulbs were cylindrical, ofabout 2 C.C. capacity. The stems were graduated in mm., and eachcm. length held from 0.02 to 0.03 C.C.Thermometers.-Three nitrogen-filled mercury thermometers wereused :(1) Reading up to 600° in 2O; standardised at the NationalPhysical Laboratory2036 PRTDEAUX : THE VAPOUR PRESSURES AND MOLECULAR(2) To 600° in 2O, and (3) to 500° in lo; these were standardisedThermostats.-For temperatures up to 260° a bath of paraffinwax was used, and for these as well as higher temperatures thevapours of liquids boiling under various pressures were employed.These have been tabulated by Landolt and Bornstein from themeasurements of Ramsay and Young as follows :by comparison with (1).260-280" ........................ Monobromonaphthaleiie.280-302" .......................Diphenylamine.360" ........................ Mercury.For the interval 31 0-339O, anthracene, boiling under diminishedpressure, was used instead of the vapour of mercury.The paraffin wax thermostat consisted of a large beaker ofresistance glass jacketed with asbestos and heated by a gas flamefrom below.Additional heat was supplied by an electrically heatedframe of iron wire in the liquid, which was stirred by a brass fanwheel at the bottom, and automatically regulated by a glasscylinder holding about 150 C.C. of air, which extended to the bottomof the liquid, and communicated by means of a capillary tubewith a mercury gas regulator. The temperature could by thismeans easily be kept constant to a few tenths of a degree. Thethermometers, etc., were not directly in contact with the liquid,but were protected by tubes of combustion glass.The vapour-bath first used had somewhat the form of it Liebig'scondenser. To a vertical glass tube open at each end was sealedan outer tube above and below.The vapour of the boiling liquidfilled the space between the tubes. The liquid was contained intwo side-bulbs joined to the lower end of the outer tube at anangle of about 45O. It was heated by burners and also electricallyby platinum spirals. The electrical heating was used mainly toprevent bumping a t low pressures. The lower part of the apparatuswas protected by an asbestos box packed with magnesia. In orderto save time, this was electrically heated by nickel wire. The upperpart was shielded by movable rings of asbestos covered with felt.It was found that this form had several disadvantages when usedfor high boiling liquids-the radiation is large compared to theevaporating surface, and the dead space between the internal sealand junction of sidetubes adds considerably to the time requiredto send the ring of condensing vapour a sufficient distance up thetube.For the purpose in hand, however, the apparatus had thegreat advantage of allowing the introduction of dilatometers frombelow, so that they could be heated from the top downwards, thusavoiding the sometimes troublesome distillation of drops of liquidto the upper part of the tubeVOLUMES OF TEE MERCURIC HALTDES. 2037In the form of vapour-bath afterwards used, the dilatometer witsintroduced from above into a glass tube about 2 cm. in diameter,which was heated by the vapour of a, liquid boiling in a muchlarger bulb, the lower end of the inner tube being protected fromthe radiation of the superheated liquid by the well-known methodrecommended for thermometers in Young's Fractional Distillation.The vapour space was connected through a reservoir of aboutYapour pressures of mercuric cldoridc, bromide, nitd i d Ic.~ 220200 1801009080i 060 2sB 50 .-s$E2u40 530 '201010 litres capacity and a drying tower to a water exhaust pump orpressure pump as the case might be. The pressures were read ona mercury manometer attached to a wooden metre scale.Vapow Pressures.-These were regulated and read by means ofthe air reservoir and mercury manometer already mentioned.Theliquids were boiled under various pressures in a combustion glasstube. The sides of the tube were protected from overheating byhorizontal pieces of asbestos board, and from cooling radiation b2038 PRIDEAUX : THE VAFOUR PRESSURES AND MOLECULARslip rings of asbestos covered with felt.The liquid was in everycase boiled at such a rate that the thermometer column was com-pletely immersed in the vapour. The bulb of the thermometer wascovered with asbestos.The results are tabulated below, and also shown in the figure.The experimental points are indicated by X. A few vapourpressures at lower temperatures by Wiedemann, Stelzner, andNiederschulte (Ber. deut. physikal. Gees., 1905, 7, 159) are indicatedas follows: mercuric chloride by circles, mercuric bromide bycrosses, and mercuric iodide by circles. Most of these were deducedfrom the loss in weight when a, measured quantity of air waspassed over the solid at the temperature in question, and some byobserving the pressure and temperature when the compounds weresuddenly sublimed into a cooled tube.The curve so obtainedought not, of course, to be continuous with that of the vapourpressures of the liquids, but the observations in the neighbourhoodof the melting point are not numerous enough for any discontinuityto be observed. The three observations recorded (by the authorsquoted above) at higher temperatures do not agree with the presentresults, probably because the method they employed was not sosuitable for higher temperatures. The pressures used for the sub-sequent calculations are those read from the manometer at 16-0°.The following are the vapour pressures (to the nearest millimetre)corresponding with the corrected temperatures.The index numbersto the right of the pressures refer to different series of experiments.Mercuric Chloride.P.(min.) to. P. to.844, 309.0 751, 303.0836, 308'2 741, 302.5822, 307.5 730, 302'7820, 308-1 724, 301.5816, 306.8 719, 301.9810, 307'5 711, 301'4803, 306.7 705, 300'5800, 307'0 702, 300.8798, 305'9 690, 300'0790, 306'4 665, 297.5781, 305.1 627, 294.8780, 305.8 612, 294*5778, 304'9 587, 292-0770, 305.0 582, 292-3766, 304'8 548, 289.0759, 304.3 544, 289.4757, 303.9 530, 287'9754, 303.6 505, 286.1Mercuric Bromide.P.(nlm.) to. P. to947, 331.0 729, 318.3897, 328'4 728, 317.8847,, 325'4 719, 317'3819, 323 9 712, 317.2819, 324.0 705, 315.8807, 323.3 705, 315.8800, 322.8 702, 316.6789, 321.8 692, 315.9779, 321.3 641, 312.2778, 321.4 6G9, 309.2772, 320.9 602, 309.5770, 320.9 562, 306.37G6, 320'7 519, 302 5760, 320.3 485, 298.5755, 320.0 410, 290.7753, 319.8 409, 292.0750, 319.5 370, 287.5749, 319.6 331, 283'0740, 319'0 252, 271.57381 318'8 225, 266'08365 324 9 7194 317.87884 322.1 680, 315.0758, 319'8 4474 296.0Mercuric Iodide.P.(mm.) to.P. t".861, 360.5 730, 351.0829, 358.3 720, 350.8821, 358.0 720, 350.5819, 357'9 711, 350-1809, 357.1 703, 349.5801, 856.8 701, 349.3799, 356'4 699, 349.3790, 355.9 646, 345.2783, 355.3 598, 341.3780, 355.1 551, 337'0770, 354.5 500, 332.0760, 353.7 453, 327.5760, 353.5 404, 321.9758, 355.5 357, 316 0750, 353.0 310, 309.5246, 352.5 270, 303.7i43, 352'5 232, 297.5740, 352.VOLUMES OF THE MERCURfC HALIDES.2039A calculation of the value of heat of vaporisation divided byabsolute temperature from the above data was undertaken, sincethis constant might be expected to throw some light on the questionas to how far these compounds partake of the nature of fused salts.The values of &/T for fused salts ought Lo be unusually high inview of the high degree of association which is usually attributedto t'hem on other grounds (Bottomley, Trans., 1903, 83, 1421;Lorenz and Kaufler, Ber., 1908, 41, 3727). The vapour-pressurecurve was first investigated by Ramsay and Young's method.Theabsolute temperatures a t which the compounds attain certain vapourpressures are tabulated below, and compared with the correspondingtemperature for a standard liquid (fluorobenzene) :TABLE I.I.P. (THgCl,).240300530 561.0700 573.0aoo 579.5860 583.090011.T( HgBr,).542-0551-5576.5589 0596.0599.8601%r i r .T(Hg1,).572.0581.5608.5622.5629.5€33 -5636'0IV. L/IV II./IV. III./IV,TC,H,F.325.5 1.665 1.7573315 1.664 1.765317.0 1.617 1'662 1.754356.0 1.610 1.655 1.749360.5 1-608 1'653 1.747393.0 1.606 1'651 1-746364.0 1.650 1-745From the above results a value of the constant was obtained inthe equation :in which TA are the temperatures of mercury halides, and 5'"~ thoseof fluorobenzene at the same pressures.'( c " for HgCI, = 0*00050.,, ,, HgBr, = 090037.The values of dP/dT were then found by a graphical method ata series of temperatures as tabulated below, and from these theheat of vaporisation Q and &IT from the formula:,, ,, HgI, = 0.00025.1*985T TE calories.Q = m( d2')Q and &IT at 760 mm.Q(ca1.) &ITHgCI,. ....................... 13910 24 *1HgBr, ..................... 14200 23 23HgI, ........................ 14700 23.5It has been shown by Nernst that the normal value of Q/Z' a2040 PRIDEAUX : THE VAFOUR PRESSURES AND MOLECULAR760 mm. increases slightly with the boiling point of the liquid inquestion according to the formula :Q/ T = 9.510g.T - O.O07T,and for a liquid boiling at 304-354O :& / T = 22.19 normally.There appears, then, t o be a certain amount of association, less,however, than in the case of water and alcohoIs, for which &/T =26.The association evidently diminishes in the order :Hg Cl ,-+Hg Br,+HgI,.Specific Gravities of the Lipuida.Procedure.-After the right weight (10-15 grams) had beenintroduced into the dilatometer, this was evacuated, sealed, andafter a preliminary heating (great care is necessary t o avoid burstingthe dilatometer) introduced into one of the thermostats andkept at each temperature until the volume remained constant.After the experiments were completed, the dilatometers wereopened and the contents boiled out, the weight of substance beingthus checked.In calculating the volumes corresponding with eachscale division of the dilatometers, the expansion of the silica was nottaken into account, since it proved to be outside the range ofaccuracy aimed at.Thus the greatest range of temperatures was from 255O to 357O.The linear expansion of silica is :0.449 x 10-6 or 0.59 x 10-6.Taking the larger figure, 3a- 1.8 x 10-6, and the total expansionof unit volume contained by a silica bulb at room temperature is4-59 x 10-4 at 255O, and 6-43 x 10-9 at 357O.The measured volumes have therefore to be increased, and thespecific gravities decreased by about 1 in 2000.This small correction has no effect on the relative specific volumes,but has been introduced into the absolute molecular volumes.Thefollowing specific gravities are calculated directly from the experi-mental data, the numbers to the left referring to different seriesof experiments in different thermostats with different quantities ofcompound and different thermometersVOTAUMES OF THE MERCURIC HALIDES. 2041t'.( 1 ) 281.0(2) 287 7290.7300'6( 7 ) 240.0244.0251.0261 -5(2) 2415248.0252'0259.0(3) 250-0(1) 254.5260.5266 0270 0276.0281 .O(2) 259.5267.5575.0D.43984'3764.3694.3485.1125'1105.0785'0465.1045.0825.0il5.0485.0i65.2365-2185.2075-1905 1695.1575 '2265.2085.li7Mercuric Chloride.t".D.(3) 290-7 4.377301.6 4.357301 'G 4.348( 4 ) 291.0 4'377301.5 4'357Mercuric Bromide.(3) 253.0258'0260 0260 '0272 0278'0286.5293.5(4) 354.55.0665.0525'0445'0625 -0445.0074-9904-9644.938Mercuric Iodide.(2) 281.0(3) 275.0279'0288.0286 *O292'0294.5301'5( 4 ) 282.55.1605 - l i 75.1665.1545.1415,1255'1135.0905.156to.(5) 311.0318.0328.0336 .O(6) 357.0(4) 302.0( 5 ) 258 52805292.0301 -5(6) 313.0320 -0329.5339.0(4) 2945301.5(5) 311.5323 0329.5337.5339 *o(6) 339.0( i ) 356.0D.4.3324.3164.2934.2764.2384 '9085-0544'9764.9445.0544'8744'8444.8114.7845.1195 0905.0755'0395.0144-9854'9784.9674'915The alteration of density with temperature can be expressed asMercuric Chloride, 280-335O :Mercuric Bromide, 240-340° :Mercuric Iodide, 255-355O :follows :D, = 4 400 - 0.0032 18 (to - 280).Dt=5*116 -0.00338 (to-240).Dt=5 238 - 0.00322 (to - 255).Densities and Vapoui Pressures of the Elements Compared withthose of Compounds.The data taken from the tables require no comment.The densities of liquid iodine are those of Billet from Constantsof Nature (Smithsonian). They appear somewhat irregular, whichis due probably to the dark colour of the vapour at the highertemperatures.Special weight has been given to the values at thelower temperatures, and that found at the boiling point byDrugman and Ramsay (Trans., 1900, 77, 1228). The columnVOL. XCVlI. G 2042 PRIDEAUX : THE VAPOUR PRESSURES AND MOLECULARheaded (( pressure " refers as throughout to that of the saturatedvapour :TABLE 11.D emi t y.Pressure. Cl,.Br,. I,. Hg. HgCI,. HgBr, HgI,.200 1.617 3.109 3'888 12.901 5.037 5'124400 1.585 3.050 3.795 12'824 4.944 5-026560 1.572 3'018 3.749 12'785 4.380 4-890 4'970760 1.558 2.985 3'705 12.747 4.348 4.840 4.920860 1.550 2.975 3-685 12'738 4'336 4.821 4.900The expansions over certain intervals of pressure are comparedwith the normal below. Since the volumes are accurate t o 0.2 percent., the expansion, for example, between 560 and 860 mm. ofmercury is 0-010 & 0.002 in the case of mercuric chloride, and thisis distinctly below the normal value. Thus for the pressure intervalnamed, the value of the ratio 0(560)/D(860) is: Normal 1.023,Hg 1.003, C1, 1.014, Br, 1.014, I, 1.017, HgC12 1.010, HgBr, 1.014,HgI, 1.014.The cause of these abnormalities is probably association as affect-ing not so much the liquid volumes as the vapour pressures, andhence the temperatures of comparison [see van't Hoff, Lectures,111, p.27 (Lehfeldt)].From the numerical values of the expansion the degree ofassociation would appear t o diminish in the order:C1, -+ Br, -+ I,; HgC1, --+ HgBr, -+ HgI,.Now, comparing the expansions of the compounds with those oftheir constituent elements, it may be seen that the magnitude ofthe abnormality is such as would be produced if the expansion wereadditively composed of the expansions of the elemenb.Yk(860) and 2 Y~l(86O) Thus the ratiosare, for HgC1, and Hg+ 2C1 .................. 1.010 and 1.012HgBr, ,, Hg+2Br ..................1.014 ,, 1.012Hgf, ,, Hg + 21 ..................... 1-014 ,, 1.015V ~ ( 5 6 0 ) ZV"(560)While the magnitude of the possible volume error (14-20 percent. on the expansion) does not permit of a certain conclusion onthis point, yet the evidence for such a relation is strengthened byan examination of the few other compounds for which data, areavailable.Thus, comparing the ratios V M and SV, at 760 and 200 mm.:PCI, ..................... 1.050 P + 3Cl .................. 1.050fC1 ..................... 1'041 I + 01 ..................... 1'043The importance of this for the question in hand rests in thVOLUMES OF THE MERCURIC HALIDES. 2043increased constancy it gives to the ratio VH/SV under variouspressures.In the first part of the paper reasons were given why the ratioshould be quite constant in the case of normal elements and com-pounds far enough removed from their critical points.It now appears that a constant ratio JT& J ~ A can also be definedfor the abnormally expanding elements and compounds considered,as may be seen from table 111.The variations of the ratios are within the limits of error to beexpected from at least one of the volume measurements involved.TABLE 111.100 JToEunzes of the Elements become on CondbinationP=860 nim.760 560101.7 -109.6 -HgC12,Hg+2Cl .................. 101.9 101.8HgBr, 107.4 107.3 - .............................. 107 *5HgI, ................................. 109 '5 109.5P=760 mm. 560 400 200PC13--+P 4- 3Cl .................. 105.6 105.2 104.9 105.0PBr3 ............................... 107'8 - - 107.5PCI, .................................96 ' 5PRr, ................................. 101 *9 - - 101.6NOTE.-The vapour pressures and atomic volumes of the phosphoriis halidesand iodine chloride (referred to on p. 2042) are taken from the tables and Trans.,1907, 91, 1711 ; 1909, 95, 445. The temperature corresponding with 200 mni. forphosphorus tribromide has been calculated by Ramsay and Young's method(comparison liquid, phosphorus trichloride).The expansion on combination therefore increases with increasingatomic weight for the mercuric halides as for the other compoundsquoted (except phosphorus pentachloride, in which case the con-traction on combination diminishes). According to the first partof this paper, the changes of volume on combination areapproximately equal to the difference between the sums of theinteratomic volumes of elementary molecules and the interatomicvolume of the compound molecule. If this is correct the physicalinterpretation to be put upon the results is that, for example, theinteratomic volume of a C1, molecule is less than that of HgC1,(Hg being monatomic), and that in the other cases (except PC1,)the sums of the interatomic volumes of the elementary moleculesare less than the interatomic volume of the compound molecule.Now, comparing together two similar combinations, such as mercuricchloride and bromide, the relative increase of interatomic volumeon combinat,ion is greater in the latter case, indicating a, smallermolecular attraction for the atoms of mercuric bromide than forthose of mercurio chloride. In the cap88 of phosphorus halides, also,- I -6 s 2044 FRANK : CONTRIBUTIONS TO OUR KNOWLEDGEthe bromide combination exhibits a smaller molecular attractionas judged by these volume relations than the chloride. Thus therelative affinities are in the few cases investigated in the sa.me orderi ~ s the same affinities deduced from other considerations.I desire t o express my thanks to the Royal Society for it grant inaid of this research, and to Professor Donnan for the facilitiesafforded at the Muspratt Laboratory and the interest he has takenin the work.THE MUSPRATT LABORATORY,THE UXIVERSITY, LIVER POO L

ISSN:0368-1645    

DOI:10.1039/CT9109702032

出版商:RSC    

年代:1910

数据来源: RSC

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2044 FRANK : ~ ~ N T R I B U T I ~ N ~ TO OUR KNOWLEDGECCXIV.-Cont.1.ibutions to o w K~iotvledye of theSulphide Dyestufls. P a r t I.By GEORGE HERBERT FRANK.SINCE the introduction of Vidal black (by R. Vidal, of Paris, in1893), which, as is well known, is prepared by fusing togetherp-aminophenol (or paminophenol and other compounds) with sodiumpolysulphide, a large number of these secalled " sulphide " dye-stuffs have been produced in a similar manner from aromaticcompounds of varied constitution. The application of these colour-ing matters, especially to cotton, is of so simple a character, andthe colours obtained are of so permanent a nature, that thesecompounds now constitute one of the most important groups ofartificial dyestuffs. Although considerable insight has been gainedas to the reactions occurring in their formation (Vidal, Mon.Sci.,1903, [iv], 17, i, 427; Pollak, Zeitsch. F a d . Ind., 1904, 3, 233, 253;Gnehm and Kaufler, Ber., 1904, 37, 2617, 3032), the subject isbeset by considerable difficulty, for the dyestuffs are as a ruleamorphous, of a comparatively insoluble nature, do not yield well-characterised derivatives, and are accordingly not easily isolated ina pure condition.During some experiments on the subject it was discovered thatthe leuco-compounds of many sulphide dyestuffs react with chloro-acetic acid, and that the substances thus obtained, when oxidised,yield interesting colouring matters, differing considerably in pro-perties from the parent substance. These new carboxyl derivativesare readily soluble in alkalis, pyridine or phenol, moderately so inboiling alcohol or acetic acid, but insoluble in dilute acids. !l%eyare well-defined colouring matters, giving shades similar to thoeOF THE SULPHIDE DYESTUFFS.PART I. 2045produced by the original sulphide dyes, and can be r e d i l y dyed onwool, but differ from the parent sulphide dyes in that they havevery little affinity for cotton.Among other points of interest attached to these mbstances itseemed possible that their closer examination would yield an insightas to the true molecular weight of the sulphide dyestuffs fromwhich they were obtained, a point which would be of considerablehelp in regard to the vexed question of their constitution.The following investigation deals with the well-known colouringmatter, immedial-indone, which is manufactured by heating togetherpaminophenol and o-toluidine with an aqueous solution of sodiumsulphide.In order to purify the commercial product, it wasrepeatedly washed with warm water, treated with dilute hydro-chloric acid until the liquor was faintly acid, and well washed.Fifty grams of the finely powdered product were reduced withsodium hydroxide and dextrose a t 60-70° in the usual manner,and treated with 20 grams of a solution of sodium chloroacetate.An increase in temperature took place, and after fifteen minutesair was aspirated through the liquid in order t o oxidise the leuco-compound. The liquid was now neutralised with dilute hydrochloricacid, the precipitated dye collected, extracted with warm sodiumcarbonate solution, the extract acidified, and the dye collected anddried; the product was now extracted with warm aniline, filteredfrom a slight residue, the solution neutralised with acid, and theprecipitate again extracted with dilute sodium carbonate solutionand acidified.As molecular-weight determinations in pyridine andnitrogen and sulphur estimations indicated that this product witsnot quite pure, it was submitted to a further treatment with warmaniline and extraction with dilute aqueous sodium carbonate in themanner above described, and finally dried in a vacuum desiccator.The compound obtained in this way contained no ash, and experi-ments indicated that it was now pure.It was of a deep blue,bronzy colour, readily soluble to a blue solution in aniline, pyridine,phenol, alkalis, or concentrated sulphuric acid, and sparingly so inhot glacial acetic acid or hot alcohol. Experiment indicated theabsence of an amino-group, and, unlike the original immedial-indone,it had no affinity for cotton when dyed in a sodium sulphide bath,neither had its sodium salt any affinity for cotton, but the lattercould be dyed on wool in the manner of an acid colour, giving abright blue colour.After being dried at 98O, it was analysed:0.1241 gave 0.2494 CO, and 0.0459 H,O.0.28009.1121 ,, 0.1376 BaSO,. S=16-88.C = 54.8 ; H =4*11.,, 17.3 C.C. N2 at 13O and 757.7 mm. N=7*402046 FRANK : CONTRIBUTIONS TO OUR KNOWLEDGE0,1312 gave 0.1559 BaSO,.S = 16.72.C17H1404N,S2 requires C = 54.4 ; H = 4.0 ; S = 17-07 ;N = 7.48 per cent.0.5 Gram of the substance was treated with 10 C.C. of N-sodiumhydroxide, and the solution was made up to 500 c.c.; by titrationwith N / 10-hydrochloric acid and employing phenolphthalein asindicator, the acidity of the compound was first determined, andthe neutral liquid thus produced was then treated with sodiumtartrate and reduced with standard titanium chloride :Found, NaOH = 21.12 per cent. of the weight of the dye.Y, H2=0.529 ,, J , 9 , ?,C17H140,N,S2 requires NaOH = 21-39 ; H,= 0.5347 per cent.Hence 189.9 parts of the colouring matter neutralise 40 parts ofsodium hydroxide, and for the reduction of 378.2 parts, 2 parts ofhydrogen are required.A determination of the molecular weight was carried out by thecryoscopic method :0-0854, in 10.3 of phenol, gave A t = - 0*14O.C,7H1404NzS2 requires M.W.= 374.When fused with sodium hydroxide, the substance undergoes aninteresting change, for not only is sulphur thus removed, but alsothe carboxyl groups are eliminated. A blue compound insoluble inwater or alkalis is thus produced. When reduced, this yields aleuco-derivative, but, unlike the corresponding leuco-derivatives ofthe sulphide dyestuffs, possesses no affinity for cotton.To obtain some further indication as to the nature of the reaction,a quantitative experiment was carried out as follows :0.5 Gram of the carboxyl derivative was fused at 200° with con-centrated aqueous sodium hydrate until a colourless pasty mass,consisting of the leuco-compound of the new substance, was pro-duced. The product when cold wits diluted with water, the mixtureneutralised with acid, and the colouring matter collected andwashed.An 'estimation of the sulphur present gave the followingresult :S = 14.89 per cent.M.W. = 377-4.0-154 gave 0.1668 BaSO,.Hence 21'5 parts of the substance contain 32 parts of sulphur.If from the found molecular weight of the carboxyl derivative wesubtract 2(CH,-CO2H) + S = 150, the new substance should have amolecular weight of 227, which is in fair agreement with the aboveresult. This experiment shows that one atom of sulphur can beremoved from the molecule of the original carboxyl derivative, butthat on the other hand, the removal does not destroy the chromo-phoric group of this compoundOF TEE SULPHIDE DYESTUFFS. PART I.2047As &medial-indone is formed from the indophenol (I) obtainedfrom paminophenol and o-toluidine, so the resultant dyestuff maybe expected to possess the skeleton (11) :NIf we assume that, as is most probable during the reaction, sulphurenters in the o-position with respect to the nitrogen atom, and thatthe phenolic group is replaced by the thiol group, leuceimmedial-indone would have the constitution (111), and immedial-indoneformula (IV) :NH N(111.)Such a constitution would offer a ready explanation of theexperiments given above. This compound would readily yield withchloroacetic acid a leuco-dicarboxylic derivative having the formula(V), and the colouring matter would be represented by (VI).NHCO,H*CH,*NHI I I/\/\/\S*CHz*CO,HCH3S(V.)NI- IVI.1This investigation therefore indicates that the most probableconstitution of immedial-indone is that given above ; further experi-ments on this difficult subject are in progress.DEPARTMENT OF TINCTORIAL CHEMISTRY,THE UNIVERSITY,LEEDS

ISSN:0368-1645    

DOI:10.1039/CT9109702044

出版商:RSC    

年代:1910

数据来源: RSC