摘要:

RUHEMANN : TRIPHENY L-2-PYRONE. 457XL IX .- Trip hen y 1- 2 -p yrone.By SIEGFRIED RUHEMANN.AFTER having found that, in the presence of sodium ethoxide, ethylphenylpropiolate condenses with P-ketonic esters or P-diketones to2-pyrone derivatives (Trans., 1899, 75, 245, 411), and that theester reacts with acetone or acetophenone to yield 4-pyrone com-pounds (Trans., 1908, 93, 431, lZSl), I have, for various reasons,thought fit to extend this research. I n the first place, it wasnecessary to examine whether the formation of 4-pyrone derivativesgenerally takes place by the action of the acetylenic ester on ketoneswith the grouping -CH,*CO. This inquiry led to the result that,so far as my observations go, this reaction is limited to those twocases, for p-tolyl methyl ketone, propiophenone, or methyl ethylketone do not condense with ethyl phenylpropiolate; the only changewhich occurs, is the transformation of the ester into the correspond-ing acid.As previously stated (Zoc. &.), this hydrolysis takesplace to some extent, also, on using acetone or acetophenone insteadof the above-named ketones, and accompanies the formation of the4-pyrone derivatives.The behaviour of ethyl phenylpropiolate towards deoxybenzoinis different. I have undertaken this investigation in connexionwith the further study on the diketopyrrolines, the results of whichwill be published at a later date. In the light of the work ondeoxybenzoin carried out by Victor Meyer and other chemists, itwas to be expected that ethyl phenylpropiolate would react withthe ketone, not'as it does with acetone or acetophenone, but inthe manner similar to the behaviour of the acetylenic ester towards&ketonic esters or P-diketones, thus :CPhiC*CO,Et + CH,Ph*COPh = O<ggc:g>CPh + C,H,O,and yield 4 : 5 : 6-triphenyl-2-pyrone.This reaction does, indeed,take place. I have subjected this compound to a, closer study withthe view of ascertaining whether, under the influence of potassiumhydroxide, it decomposes thus :C23HI609 + 2KH0 = C6H,*C(CH2*CcH,) :CH*CO,K + C,H,*@O,K.I find that only part of the pyrone compound breaks up in thisway to form B-benzylcinnamic acid, melting a t 168-169O. Theformation of this acid is of some interest for the following reason.Whereas the homologues of cinnamic acid with the formulaC,H,-CH:CR=CO,Et are readily produced according to Perkin'458 RUHEMANN : TRIPHENYL-2-PYRONE,reaction, it is only recently that Schroeter (Ber., 1904, 37, 1090;1907, 40, 1589; 1908, 41, 5) was able to obtain P-alkylcinnamicacids from the products of the action of zinc or magnesium on themixture of aromatic ketones and ethyl iodoacetate (see, also, Rupeand Busolt, Ber., 1907, 40, 4537).Like Michael and Palmer's(Amer. Chem. J., 1885, 7, 69) a-benzylcinnamic acid, which on re-duction yields dibenzylacetic acid, (C6H5-CH2)2*CH*C02H, p-benzyl-cinnamic acid, on treatment with sodium amalgam, is transformedinto p-phenyl-P-benzylpropionic acid,C6H,*CH(CH2*C6H,) *CH2-C02H.Again, just as a-benzylcinnamic acid, under the influence of coldconcentrated sulphuric acid, condenses to form benzylidene-a-hydrindone, C6H,<!2>C:CH*C6H5 (see Schmid, J.pr.Chem., 1900, [ii], 62, 550), p-benzylcinnamic acid is transformedinto 3-phenyl-1-napht hol :C( 0 H): $lHThe formation of P-benzylcinnamic acid (m. p. 168-169O) isaccompanied by the production of an isomeride melting between76" and 90°, which, as yet, I have failed to obtain with afixed melting point. But the action of potassium hydroxide ontriphenyl-2-pyrone is still more complicated, because part of thepyrone compound undergoes the following change :C,H4<CH =rC*C,H,'The fact that the product C,,Hl,O, which is formed, does notmelt sharply, indicates that it is a mixture, and leads to the viewthat the compound CH2:C(C6H,)*CH(CGH,)*COoCsH5, which maybe expected to be first produced, under the influence of the alkali,is partly or wholly transformed into a mixture of stereoisomeridesof phenylethylidenedeoxybenzoin, CH3=C(C,H5):C(C6H,).CO*C6H,.All attempts to separate this mixture by crystallisation have beenunsuccessful. Compounds which belong t o the same type are knownalready. These are the alkylidenedeoxybenzoins which Klages andTetzner (Ber., 1902, 35, 3965) prepared from deoxybenzoin.Isomeric with the product C2,H180, which is formed from triphenyl-2-pyrone, is p-methylbenzylidenedeoxybenzoin,This substance was obtained by those chemists on condensingdeoxybenzoin with p-tolusldehyde, and was found to exist in twoforms, which could be separated.CH,*C6H,'cH : c( C6H,)*CO*C6H5HUHEMANN : TRIPHENYL-2-PYRONE.459EXPERIMENTAL,Formation of 4 : 5 : 6-Tr~phenyl-fL-pyl.onc,O<Co-cH>CPh. CPh:CPhThis substance is formed on adding deoxybenzoin (9-8 grams) todry sodium ethoxide (3.4 grams) suspended in absolute ether, andthen ethyl phenylpropiolate (8.7 grams) to the solution which isshortly produced. The mixture becomes red, and a yellow solidseparates. The reaction is complete in the course of a day; wateris then added, when part of the solid (8 grams) remains undissolved.This is insoluble in water or alcohol; it dissolves sparingly in cold,moderately in boiling, glacial acetic acid, and, on cooling, crystallisesin faintly yellow prisms, which melt at 245-246O:6.2030 gave 0.6342 CO, and 0.0930 H,O.Cz3Hl6O2 requires C = 85.18 ; H = 4.94 per cent.The yield of this substance is only 50 per cent.of the theoretical;this is due to the fact that part of the ethyl phenylpropiolate istransformed into the acid, which, together with the unattackeddeoxybenzoin, is contained in the ethereal layer from the product ofthe reaction.C = 85.20 ; H = 5-09.Action, of Potassium Hydroxide o n Triphenyl-2-pyrone.On boiling the pyrone with an excess of alcoholic potassiumhydroxide on the water-bath, it dissolves, yielding a deep redsolution, and finally a yellow solid. After four to five hours'heating, the alcohol is distilled off, water added to the residue, andthe whole extracted with ether. On evaporation of the ether, ayellowish-red oil is left behind, which gradually sets almost com-pletely, t o a solid.This is washed with a little dilute alcohol,when it becomes quite white. This product is a mixture of thestereoisomerides of phenylethylidened eoxy b eneoin,CH3-C( C6H5) :c( C6H,)-C0 C6H,.It readily dissolves in hot alcohol, and, on cooling, crystallises incolourless prisms, which begin to soften at 76O, and are completelymelted a t 90°:0.1882 gave 0.6110 CO, and 0*1090 H,O. C = 88.54 ; H = 6-13.0.1970 ,, 0.6400 CO, ,, 0*1080 H20. C=88*60; H=6*09.C,,H,,O requires C = 88.59 ; H = 6.04 per cent.The substance is very soluble in carbon disulphide, and moderatelyso in light petroleum; it dissolves slowly in cold concentrated sul-phuric acid, forming a red solution.I have repeatedly crystallise460 RUHEMANN : TRIPHENYL-2-PYRONE.the product from alcohol as well as from light petroleum, but allthe fractions, on melting, showed practically the same behaviour,and, on analysis, gave the same results.The alkaline solution from the product of the action of potassiumhydroxide on the pyrone, which contains a mixture of benzoic acidand the isomeric 8-benzylcinnamic acids, is mixed with an excess ofdilute sulphuric acid and repeatedly extracted with ether. Onevaporation of the ether, a yellow oil is left behind, which sets toa solid after a few hours. When this is washed with cold dilutealcohol, @-benzyIcinnamic acid remains undissolved.The acid is only sparingly soluble in cold alcohol, but readilyso in boiling alcohol, and, on cooling, separates in long, colourlessneedles, which melt at 168-1 69O :0-2028 gave 0-5992 CO, and 0-1080 H;O.Cl6Hl,O, requires C = 80.64 ; H = 5.88 per cent.8-Benzylcinnamic acid is readily soluble in ammonia, and thissolution, on the addition of silver nitrate, yields a white silver salt,which is sparingly soluble in boiling water :C =80*58; H=5*92.0.2595 gave 0.0810 Ag.Ag=31.21.C,,H&,Ag requires Ag = 31-30 per cent.8-PheqZ-8-6 enzylpropionic A cid, C,H,-CH (CH,*C,H,)*CH,*CO,H.The reduction of P-benzylcinnamic acid readily takes place ondissolving it in dilute sodium hydroxide and shaking the solutionwith an excess of sodium amalgam (Zi per cent.) for about half anhour. The alkaline liquor is poured off and mixed with dilutehydrochloric acid, when an oil separates which solidifies in thecourse of a day.The solid is sparingly soluble in light petroleum,readily so in chloroform or alcohol; on adding water to the hotalcoholic solution until it becomes turbid, colourless prisms graduallyseparate, which melt. at 95-96O :0.1978 gave 0.5810 CO, and 0.1190 H,O.C16H1602 requires C = 80.0 ; H = 6.67 per cent.The silver salt, which is formed on the addition of silver nitrateto the ammoniacal solution of the acid, is white, and does notchange on drying in the water-oven :Ag= 31-09.C1,Hl,0,Ag requires Ag = 31.12 per cent.C=80*10; H=6*71.0.2438 gave 0.0758 AgRUHEMANN : TRIPHENY L-8-PYRONE. 461CH=F*C,H,C(0H):CH '3-Phenyl- 1-napht hol, C,H,<On adding cold concentrated sulphuric acid to P-benzylcinnamicacid, the crystals gradually dissolve, forming a red solution which,when kept overnight and then slowly poured into cold water, yieldsan oil.This gradually sets to a solid, which is sparingly soluble inboiling water, readily so in ether, chloroform, or alcohol; it ispurified by adding water to the alcoholic solution until an emulsionis produced, from which light brown needles, melting at 100-lO1°,separate :0.1883 gave 0.6023 CO, and 0.0950 H,O.C16H,,0 requires C = 87.27 ; H=5*45 per cent.This compound is very soluble in alkalis, and does not give acolour reaction on the addition of ferric chloride to its alcoholicsolution.The alkaline solution, which is formed by the action of potassiumhydroxide on triphenyl-2-pyroneY contains, besides P-benzylcinnamicacid, melting a t 168--169O, its isomeride.This, being very solublein alcohol, remains in the original alcoholic filtrate from the formeracid, together with benzoic acid, which, also, is produced in thereaction. In order to remove the benzoic acid, water is added tothe filtrate, and the whole extracted with ether. The productwhich is left behind on evaporation of the ether is distilled in acurrent of steam, the benzoic acid contained in the distillate isextracted with ether, and, after evaporation of the ether, re-crystallised from water. The isomeride of P-benzylcinnamic acidis not volatile with steam, and remains in the distilling flask as anoil, which slowly solidifies. The solid is very soluble in alcohol,ether, warm carbon disulphide, or chloroform, sparingly so in lightpetroleum. The solution in the latter solvent gradually depositsstout prisms, which soften a t 104O, and are completely melted at1 1 6 O . That this substance is isomeric with fl-benzylcinnamic acid,melting a t 168O, is proved by the following analysis :C = 87-23 ; H = 5.60.0.1900 gave 0.5620 CO, and 0-1023 H,O.C,,H1,O, requires C = 80.64 ; €1 = 5.88 per cent.The fact that this substance does not fuse sharply seems toindicate that it is not pure, but after repeated crystallisations fromdilute alcohol or light petroleum, the behaviour on melting ispractically unaltered.C = 80.67 ; H= 5-98.UNIVERSITY CHEMICAL LABORATORY,CAMBRIDGE

ISSN:0368-1645    

DOI:10.1039/CT9109700457

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

462 RUHEMANN : DIKETODIPHENYLPYRROLIKEL . -Dike t o dip he n y lp yrro lin e and its A izal oyues.Part III.By SIEGFRIED RUHEMANN.THE formation of the diketodiphenylpyrrolines by the action ofethyl phenylpropiolate on the sodium derivatives of aromatic amidesis accompanied by the production of colourless compounds (seeRuhemann, Trans., 1909, 95, 984, 1603). One of these substanceshad been isolated previously (Zoc. cit.) from the product of thereaction of sodiobenzamide with the acetylenic ester, and its formulawas found to be C23E1,03Nz. With regard to its constitution, theview was expressed that this substance was the result of the unionof benzamide with the first formed phenylpropiolylbenzamide, andthat, accordingly, it was represented thus :C6H,*C ( NH°CO*CGH5) :CH*CO-NH°CO*C6H5.A closer investigation, however, did not confirm this view; for thecolourless substance, C23HlS03N2, on boiling with potassiumhydroxide decomposes to yield deoxybenzoin, and with cold con-centrated sulphuric acid breaks up quantitatively into diketodi-phenylpyrroline and benzamide.This behaviour, and the factthat the compound has no basic properties, lead to the conclusionthat it is to be regarded as an additive product of diketo-diphenylpgrroline with benzamide. Its constitution, therefore, isto be exmessed thus. Iand it is therefore 3-benzoylamino-3-hydroxy-2-keto-4 : 5-diphenyl-p yrroline.This result induced me to examine whether the diketopyrrolineforms additive products with other substances, and in this respect,also, resembles isatin.It was found, indeed, that, like the lattercompound (see Baumann, Ber., 1885, 18, 890), the diketopyrrolinereadily unites with phenylmercaptan to yield an additive com-pound, C16~,,02N,C6H6S, which undoubtedly has a constitutionsimilar to the additive product with benzamide, and which readilydecomposes into its constituents, phenylmercaptan and the diketo-pyrroline. With piperidine, the diketopyrroline combines even inthe cold to form the compound C,6H,,02N,C5Hl,N. This is morestable than the former substance, and does not decompose until itssolutions in mineral acids are heated, when the diketopyrrolineseparates. The behaviour of piperidine towards isatin was examineAND ITS ANALOGUES. PART 111. 463by Schotten (Ber., 1891, 24, 1367), who carried out the reaction a tthe temperature of the water-bath, and thus obtained dipiperidyl-isatin,"6H4<--&d5-- C(CH N)2>C().The resemblance between isatin and the diketopyrrolines isfurther indicated by the fact that they give the indopheninereaction.On shaking their solutions in concentrated sulphuricacid with benzene which contains thiophen, the red colour firstchanges to brown, and then gradually turns blue. Like isatin,diketodiphenylpyrroline condenses with phenol in the presence ofconcentrated sulphuric acid, and forms 2-keto-3 : 3-bishydroxy-phenyl-4 : 5-diphenylpyrroline,CPh:yPh(C6H4*0H)2C<~~-N~ 'It may finally be stated that the relation which isatin exhibits tothe diketopyrrolines as well as to the diketo-derivatives of cyclo-pentene extends also to the diketopyrazolines :P ? > C O .N*NROne member of this class of compounds, namely, 4 : 5-diketo-l-phenyl-3-methylpyrazoline, was first prepared by Knorr and Pschorr(Annulen, 1887, 238, 194) ; afterwards Sachs and Barschall (Bey.,1902, 35, 1437; 1903, 36, 1132) obtained diketopyrazolines by theaction of nitrosodimethylaniline on the pyrazolones and subsequenttreatment of the former condensation products with mineral acids.Up to the present, however, no member of this group of diketo-compounds is known in which the iminic hydrogen of the pyrazolinering is intact.I propose to prepare such substances with theview of ascertaining whether they behave towards alkalis like theiranalogues and form blue salts.EXPERIMENTAL.3-Benzo ylamino-3-hydro xy-2-ke t 0-4 : 5-diph enylpyrroline,CPh:QPhCO-NH 'C,H,.CO-NH*C(OH)<On boiling this compound with an excess of concentratedpotassium hydroxide, it decomposes and yields ammonia, deoxy-benzoin, oxalic acid, and benzoic acid, thus:C2,H,;03N2 + 3EHO + H,O =C,H,*CH2*CO0C6H, + (CO2E)z + C,H,*CO,K + 2NH3.The heating was continued until ammonia ceased to be evolved464 RUHEMANN : DIKETODIPHENYLPYRROLINEsteam was then passed through the product of the reaction, whena solid slowly passed over which, after crystallisation from lightpetroleum, melted at 60-61O.This substance was deoxybenzoin :0.1732 gave 0.5440 CO, and 0.0962 H,O.Cl4Rl20 requires C = 85-71 ; H = 6.12 per cent.The remaining alkaline solution was treated with an excess ofdilute sulphuric acid and subjected to steam distillation.Thebenzoic acid which is contained in the distillate was extracted withether, recrystallised from water, and identified by the melting point.The formation of oxalic acid in the reaction was ascertained bythe usual test.The result of the action of potassium hydroxide on the colourlesssubstance C23H18O3NZ indicates that it is an additive product ofdiketodiphenylpyrrolint? with benzamide, and this conclusion issupported by the fact that, with sulphuric acid, the substance breaksnp into these components. On adding the colourless compound tothe concentrated acid, it dissolved, yielding a deep red solut,ion.This, after being kept overnight, was gradually poured into coldwater, and the diketodiphenylpyrroline, which separated, wascrystallised from dilute alcohol.It softens a t 1 8 4 O , and melts a t190-191O (instead of 184O, which was previously given as themelting point) :C=85-66; H=6-17.0.1948 gave 0.5505 CO, and 0.0820 H,O.C1,HllO,N requires C = 77-11 ; H = 4.42 per cent.The benzamide which is contained in ths filtrate from the diketo-pyrroline was extracted with ether, and, on evaporation of theether, remained as a red solid, which, after crystallisation fromwater, melted a t 130O:C=77*07; H=4.67.0.2338 gave 24.2 C.C. N, at 18O and 754 mm. N=11*84.C,HiON requires N = 11-57 per cent.A dditive Product of Dike t odiphen ylpgrroline and Phen ylmercaptan,This additive product is readily .formed on adding phenyl-mercaptan to the diketopyrroline, dissolved in hot alcohol.Thedeep colour of the solution turns light red, and faintly pink platessoon separate. These were washed with ether and dried in avacuum desiccator over sulphuric acid. The substance reddens atabout 140°, and melts a t 1’74-175O:C=73*68; H=4*96.C,,H,,O,NS requires C = 73-53 ; €I = 4.74 ; S= 8-91 per cent.C,,H,,O,N,@,W.0.1760 gave 0.4755 CO, and 0.0785 H,O.0.2240 ,, 0.1476 BaSO,; S=9-05.On adding this compound to cold concentrated sulphuric acidAND ITS ANALOGUES. PART 111. 465heat is developed, the odour of phenylmercaptan is perceptible, anda, deep red solution is produced, which yields a precipitate of diketo-diphenylpyrroline when poured into water.Additive Product of D i k e t o d i p ~ e n y l ~ r r o l i n e and Piperidine,On adding piperidine to the diketopyrroline dissolved in ether,the red colour of the solution changes to yellow, and, after a shorttime, faintly brown, glistening prisms separate, which melt anddecompose a t 180-181O :C16H1102N7C5HllN'0.1632 gave 12.2 C.C.N , at 20° and 749 mm.C2,H,,O2N, requires N = 8.38 per cent.The substance is rather stable towards mineral acids; decom-position into its constituents, the diketopyrroline and piperidine,does not take place until the solutions are heated.N=8.42.2-Keto-3 : 3-Bishyd~oxyphenyl-4 : 5-diphenylpyrroline,Phenol reacts with diketodiphenylpyrroline under the same con-ditions as with isatin (see von Baeyer and Lazarus, Ber., 1885,18, 2641). The diketopyrroline (2 grams) was dissolved in anexcess of phenol, and, gradually, concentrated sulphuric acid wasadded until the red colour of the solution turned deep brown. Thewhole was then poured into water, when a yellow, flocculent solidwas precipitated. This was dissolved in ether, and the solutionmixed with chloroform until it became turbid. In the course ofa few hours, yellow plates separated, which retained their coloureven on boiling the alcoholic solution with animal charcoal. Thesubstance melts a t 220-221O :0.1600 gave 0.4697 CO, and 0.0755 H,O.0.2420 ,, 7.2 C.C. N, at 17O and 747 mm. N=3.39.C,8H,,0,N requires C = 80.19 ; H = 5.01 ; N = 3.34 per cent.This compound is sparingly soluble in chloroform or benzene,moderately so in ether or cold alcohol, but readily so in boilingalcohol. It dissolves in potassium hydroxide, yielding a yellowsolution, from which it is precipitated unchanged on the additionof hydrochloric acid.C =80.06; H=5*24.UNIVERSITY CHEMICAL LABORATORY,CAMBRIDGE

ISSN:0368-1645    

DOI:10.1039/CT9109700462

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

466 BARGI-ER: THE CONSTITUTION OF CARPAINE. PART I.LI.-The Constitution of Cwpaine. Part I.By GEORGE BARGER.THE alkaloid carpaine was discovered by Greshoff in the leaves ofthe Papaw tree, Carica Papaya, L. (Mededeelingem uit 's LandsYlantentuin, No. 7 , Batavia, 1890, p. 5). Merck (Jahresber., 1891,p. 30) assigned to it the formula C,,H,,O,N, but van Ryn (Znaug.Diss. Marburg, 1892; Arch. Pharm., 1893, 231, 184; 1897, 235,332) corrected this to C,,H,,O,N. Van Ryn described a numberof salts, and showed that carpaine is a secondary base yielding anitroso-derivative, C,,H,~O,N*NO, and that on methylation andethylation a tertiary base and quaternary iodide are produced. Healso attempted to obtain a knowledge of the constitution byoxidation with potassium permanganate, but his experiments in thisdirection were unsuccessful.The alkaloid f o r the present investigation was prepared fromPapaw leaves from British India; the yield was 0.07 per cent., orthe same as that obtained by Greshoff from adult leaves (youngleaves contain three to four times as much).The experimental results which have been obtained so far showthat carpaine is the internal anhydride of a, substance possessingboth acid and basic properties, and closely resembling certain amino-acids; this substance contains a carboxyl group, and has the com-position C,,H,,O,N; the name carpamic acid is suggested for it.Byoxidation with potassium permanganate, or preferably with nitricacid, a dibasic acid of the composition C,H,,O, is formed, which isprobably as-dimethyladipic acid ; this acid might result from thebreaking down of a dimethylcy clohexane ring.Like carpaine itself,the ethyl ester of carpamic acid yields a nitroso-derivative, whenceit follows that the alkaloid cannot be a lactam, but must be alactone, and that its two oxygen atoms are arranged as follows:iC*O*OO*. Although there is at present no direct evidence, it thusappears very probable that carpamic acid contains an alcoholichydroxyl in addition to a carboxyl group and an imino-group; ifattached to the cyclohexane ring, this hydroxyl would be convertedon oxidation into one of the carboxyl groups of the acid C,H,,O,.In this case the carboxyl group of carpamic acid could not bedirectly connected to the cyclohexane ring, but would be attachedto the rest of the molecule.The oxidation of carpaine by potassiumpermanganate (see below) affords some evidence that the nitrogenatom is directly attached to the complex yielding the acid C8HI4O4;the rest of the molecule left unaccounted for is a bivalent groupBARGER: THE CONSTITUTION OF CARPAINE. PART I. 467C,H,,. The subjoined largely hypothetical formula will serve toMe Hshow that if carpaine contains 25 hydrogen atoms, there can onlybe one homocyclic ring, in addition to the lactone ring. Withregard to the complex C5HI0, nothing is known at present.EXPERINENTAL.Composition and Properties of Carpaine.Van Ryn’s analyses agree closely with the formula C,,H2,02N,and so far it was thought unnecessary to confirm this. It is,however, supported indirectly by the analyses of carpamic acidand its derivatives.Merck’s formula, C?,,H2,02N, is certainlyincorrect, and the only other formula, C,,H,,O,N, is hardly morelikely.The properties of carpaine have been fully described by van Ryn,except the fact that the alkaloid can be distilled without decom-position. I n a vacuum produced by charcoal and liquid air (thepressure was a fraction of a millimetre), 2 grams of carpaine weredistilled with the bath at 260-290°, and the vapour at 215-235O.The distillate crystallised in the receiver, and at once showed themelting point 121O (corr.), identical with that given by van Ryn.Action of Acids on Carpaine: Carparnic Acid.Van Ryn attempted to hydrolyse carpaine by boiling it with1 per cent.alcoholic hydrogen chloride, but after twelve hoursalmost the whole of the alkaloid was recovered unchanged. Thisacid was much too dilute, and the temperature too low. Whenheated in a sealed tube to 130-140° for a few hours with 10 percent. hydrochloric or sulphuric acid, carpaine is quantitativelychanged to a substance containing one molecule of water more thancarpaine. The same change may be brought about more slowlyby boiling with 20 per cent. hydrochloric acid. The completion ofthe change is best detected by the disappearance of the intenselybitter taste of carpaine. When sulphuric acid has been used it maybe removed with baryta, which does not precipitate the product ofhydrolysis; in the case of hydrochloric acid, the excess of the acidcan be removed by distillation under diminished pressure.TheVOL. XCVII. I 468 BARGEll: THE CONSTITUTION OF CARPAINE. PART I.hydrochloride of carpamic acid remains behind as a syrup, andcrystallises on cooling. It may be recrystdlised from acetone, orby adding ether to its alcoholic solution, and forms needles meltinga t 161O:0.1320 gave 0.2778 CO, and 0.1107 H20. C = 57.4 ; H = 9.3.0.1270 ,, 0.0627 AgC1. C1=12*2.C,,H,,03N,HC1 requires C = 57-2 ; H = 9-5 ; C1= 12-1 per cent.The free base may be obtained from the hydrochloride by decom-position with the calculated quantity of sodium carbonate, but it5the substance is readily soluble in water and scarcely more solublein alcohol than sodium chloride, it is d a c u l t to obtain it quite freefrom salt by this means.It is therefore better to decompose thesulphate with baryta, or the hydrochloride with moist silver oxide,and to crystallise the residue left on evaporating the aqueousfiltrate from dilute alcohol. It also crystallises very well on addingacetone to the cold alcoholic solution.Carpamic acid, obtained in this manner, forms long needles, melt-ing a t 224O. Under a pressure of less than 1 mm., the substancesublimes unchanged ; when heated under atmospheric pressure, itdistils with slight decomposition :0.1212 gave 0.2925 CO, and 0.1139 H20.The substance is optically active ; in aqueous solution :+ 7*0°.C = 65.8; H = 10.4.C1,H2,O3N requires C = 65.4 ; H = 10.5 per cent.I = 1-dcm.; c = 3.727 ; a, + 0-26O ; [a]Carpamic acid is readily soluble in cold water, but only verysparingly so in alcohol; it is insoluble in acetone, ether, and mostother organic solvenb. The salts with mineral acids and with thealkali metals are readily soluble in water; the barium salt is a stiffjelly, so that the, test-tube in which it is formed can be inverted.Carpamic acid has a hardly perceptible, faintly sweet taste, like someamino-acids; when pure and free from carpaine, the intense bittertaste of the latter alkaloid is absent. In dilute solution carpamicacid does not yield preciEitates with potassium tri-iodide or withpotassium mercuri-iodide, differing therein from carpaine ; bothbases, however, yield a precipitate with phosphomolybdic acid.In solubilities, volatility, and chemical reactions, carpamic acidclosely resembles certain amino-acids like leucine, but it has moredefinitely basic properties than are associated with a-amino-acids.The presence of a carboxyl group is demonstrated by esterification.Thus, when carpamic acid is suspended in absolute alcohol andtreated with hydrogen chloride, there remains on evaporation ofthe acid a syrup, which crystallises on the addition of ether to itBARGER: THE CONSTITUTION OF CARPAINE. PART I.469concentrated alcoholic solution, forming needles, melting at171--172O, and consisting of the hydrochloride of etliyl carpamate :0.1354 gave 0.2968 CO, and 0.1178 Hi0C,,H,,O,N,HCl requires C =59.7 ; H = 9.9 per cent.The same hydrochloride is formed almost quantitatively directfrom carpaine by hydrolysis with alcoholic (instead of with aqueous)hydrochloric acid.For instance, 0.5 gram of carpaine, heated with5 C.C. of 10 per cent. alcoholic hydrogen chloride for two hours to160°, yielded 0.51 gram of this hydrochloride on addition of etherto its concentrated alcoholic solution.The hydrochloride of ethyl carpamate is tasteless ; its aqueoussolution is precipitated by sodium carbonate. The free ester baseis readily soluble in ether; it has not yet been crystallised.From the above description it will be seen that carpaine andcarpamic acid are related to each other in the same way as ergotinineand ergotoxine (Barger and Ewins, this vol., p. 284). Both carpaineand ergotinine are converted by acids in alcoholic solution intosalts of an ester.C=59*8; H=9*7.Action of Alkulis on Carpaine.Thus, after 0.2 gramhad been heated with 2 C.C.of 10 per cent. aqueous sodiumhydroxide to 140-150° for three and a-half hours, 0.16 gram ofcarpaine was recovered unchanged. The carpaine was hardlyattacked, because it is insoluble in water. In a similar experimentwith 2 C.C. of 2.5N-sodium ethoxide, carpamic acid was formed, andwhen 0.2 gram had been heated to 180° for two hours with 4 C.C.of 3.3N-sodium ethoxide, 0.12 gram of carpamic acid was obtained.When0.5 gram of carpaine was heated with 7 grams of potassiumhydroxide and 0.5 C.C. of water, no apparent change took placebelow 300O. Then a dark brown solution was gradually formed,and, on cooling, hydrochloric acid yielded an oily precipitate solublein ether with intense fluorescence.On evaporation, the ether lefta red oil, which with ferric chloride yielded a reddish-browncoloration. It would appear that under these conditions a phenolis formed (by oxidation of a cyclohexane ring); a similar productwas also obtained on chlorinating carpaine and treating the productwith alkali (see below).Carpaine is extremely resistant to alkalis.On fusion with alkali, a further change may take place.Further Degradation of Carpamic Acid.I none experiment 0.2 gram of carpaic acid was boiled with 6 C.C. ofThis cannot readily be brought about by boiling with alkali.I 1 470 BARGER: THE CONSTITUTION OF CARPAINE. PART I.50 per cent.potassium hydroxide solution. The potassium salt ofthe acid floated on top as a brown oil, and during half an hour'sboiling very little, if any, of a volatile base was given off,corresponding a t most to one-fiftieth of the nitrogen present. Oncooling, the upper layer crystallised ; it yielded, on acidification,unchanged carpamic acid.By distilling carpamic acid with lime under diminished pressure,a little of an oily base is formed, insoluble in water, but soluble inether. A similar base is formed on heating carpamic acid (orcarpaine) with concentrated hydrochloric acid to 225-250O. Inboth cases the carboxyl group of carpamic acid seems to beeliminated, but neither reaction has been studied further for wantof material.Oxidation of Carpahe.Van Ryn foundthat acid potassium permanganate is only very slowly decoloriseda t room temperature.By heating on the water-bath (in dilutesulphuric acid solution), oxidation was more rapid, and he obtaineda mixture of crystalline, non-nitrogenous acids, the yield of whichwas, however, only 74 per cent. of the alkaloid employed. Bycrystallisation from water, three fractions were obtained, meltingcontinuously from 70-124O ; the small yield of material availabledid not enable van Ryn t o isolate any of the acids in a state ofpurity, and no analysis was made. The only other product obtainedwas ammonia.In view of the difficulties encountered by van Ryn, it was thoughtadvisable to modify the conditions of oxidation by using neutralpotassium permanganate in acetone solution, a method which hasof late yielded such good results in the case of brucine andstrychnine (Leuchs, Ber., 1908, 41, 1711).Five grams of carpainewere dissolved in 125 C.C. of acetone, and 1-11 grams of finelypowdered potassium permanganate (half an atomic proportion ofoxygen) was added to the solution after cooling to Oo. The pinkcolour disappeared only very slowly. The solution was thereforewarmed t o room temperature, when the permanganate was com-pletely reduced in a fep. hours. The same quantity was then againadded; finally, when two atoms of oxygen had been used up, thesolution was filtered, and was found to contain 24-3 grams ofthe unchanged alkaloid.In a, second experiment 5 grams of carpaine in 140 C.C.of acetonewere at once treated with 3-33 grams of potassium permanganate( = 14 atoms of oxygen) ; the temperature gradually rose from 23Oto 37O, and then fell; the pink colour disappeared in half an hour.In all, 9 atoms of oxygen were supplied; the addition of per-Carpaine is fairly resistant to oxidising agentsBARQER: THE CONSTITUTION OF CARPAINE. PART I. 471manganate, representing the last atom of oxygen, produced a, riseof temperature only from 21-25O, and this time the pink colourpersisted after seven hours. On filtration, the acetone was foundto contain only a minute quantity of a neutral substance, meltingat about 50°. The mixture of manganese dioxide and potassiumsalts was extracted with water (by shaking, glass beads beingadded). The pale brown solution was washed with ether, whichdid not remove an appreciable amount of substance; the solutionwas then acidified and became turbid; by repeated extracting withether, 2.5 grams of a brown syrup were now obtained, but theaqueous solution still held in suspension a considerable quantity ofa brown, oily substance, which was almost insoluble in ether.Thesyrup extracted by ether was esterified with methyl alcohol andhydrogen chloride, and was %hen distilled ; between 1 10-120° a t apressure of 3-4 mm., there was collected a small quantity of a dis-tillate, which was hydrolysed by boiling with potassium hydroxide ;a t the same time an alkaline gas (ammonia or an amine) wasevolved. On acidification, 0.15 gram of an acid was obtained,which, on crystallisation from benzene, formed leaflets, melting notquite sharply at 98-looo.This acid was free from nitrogen, andwas analysed:0.0682 gave 0.1398 CO, and 0.0496 H20. C=55*9; H =8-1.[C,H1204 requires C = 55.8 ; H = 7.0 per cent.]C8H1404 ,, C=55.2; H=8*0 ,,The molecular weight was determined by the author’s microscopic0.0487, in 1.2744 grams methyl alcohol, was intermediate betweenmethod (Trans., 1904, 85, 286) :0.20 and 0.21 mol. bend. M.W.=182-191, mean 186.C,H,404 requires M.W. = 174.0-0164 gram of acid required for neutralisation 1-62 C.C.In the distillation of the ester a small quantity of a semi-solidfraction was further collected, boiling at 120-200°/3 mm., butthe bulk of the material decomposed in the flask.It thus becameevident that much more than 5 grams of the alkaloid would berequired for the complete characterisation of the acid (van Rynobtained no result from the oxidation of 10 grams with potassiumpermanganate). Other oxidising agents were therefore employed,and among these nitric acid was found to be much the mostsuitable. 0.2 Gram of carpaine, heated in a sealed tube with2 C.C. of nitric acid (D 1.41) to 140-170°, yielded only a minutequantity of an acid soluble in water, which on heating gave anodour similar to that of succinic anhydride; there was no trace ofN/lO-KOH, whence M.W. for a dibasic acid = 204472 BARGER: THE CONSTITUTION OF CARPAINE. PART I.an alkaloidal substance. On opening the tube there was greatpressure, most of the alkaloid having been oxidised to carbondioxide.In a similar experiment with acid of density 1-32, 40 percent. of a dibasic acid was obtained, and after a large number ofsuch experiments the exact conditions were found for obtaining amixture of non-nitrogenous acids weighing 75 per cent,. of thealkaloid employed. This mixture is at present under investigation,and from it an acid of the composition C,H1404 has been isolated,which is probably a mixture of the two stereoisomeric forms ofas-dimethyladipic acid, the same mixture having previously beenobtained in very much smaller amount with potassium per-manganate.The oxidation of carpaine by halogens was also attempted.When chlorine is passed into a cold aqueous solution of the hydro-chloride, the whole of the alkaloid is gradually precipitated as anamorphous chloro-derivative, which is decomposed by boiling alcohol,but can be crystallised from methyl alcohol (with considerable loss),forming leaflets, melting and decomposing at 77O :0.0981 * gave 0.1854 CO, and 0.0618 H,O.C = 51.7 ; H = 7.0.0.1247 5- ,, 0'1132 AgC1. C1=22.5.C14H,,0,NC1, requires C = 51.8 ; H = 7.1 ; C1= 21.9.This substance is neutral; two hydrogen atoms have been replacedby an oxygen atom and two chlorine atoms; it is therefore dichloro-oxycarpaine, and as it is formed quantitatively, it was thought thatit might form a suitable starting point for further degradation.The chlorine is very readily removed, by cold pyridine, for instance,but the substance is not simply a perchloride. A somewhat pro-found change has taken place; carpaine cannot be recovered fromit, and by treatment with alkali a pink, fluorescent solution isobtained (benzene derivative 2). So far it has been found impossibleto obtain any further derivative in a pure state.On passing chlorine into a solution of carpamic acid, a similarderivative is formed, which could not, however, be crystallised.Bromine produces in a solution of a carpaine salt an orangeprecipitate of a perbromide, from which carpaine is readilyregenerated.In comparing the oxidation by potassium permanganate inacetone solution with that by nitric acid a t 130°, it should be notedthat the latter reagent first hydrolyses the alkaloid to carpamicacid, which thus becomes open to attack. A non-nitrogenous acidis then formed, but potassium permanganate first produces a nitro-genous acid, which is only slightly soluble in ether. After dis-* Crystallised. j- Amorphous, dried in a vacuumMCRENZIE AND WREN : OPTICALLY ACTIVE GLYCOLS. 473tillation the ester of this acid gave off an amine or ammonia onhydrolysis, the same acid, C8HI4O4, resulting. From this it wouldappear that the nitrogen atom is directly attached to the complexyielding this acid.THE GOLDSMITHS’ COLLEGE,NEW CROSS, LONDON, S.E

ISSN:0368-1645    

DOI:10.1039/CT9109700466

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

MCRENZIE AND WREN : OPTICALLY ACTIVE GLYCOLS. 473LI1.-Optically Active Glycols Derived from 1-Benzoinand from Methyl 1-Mandelate.By ALEX. MCKENZIE and HENRY WREN.THE work described in the present communication was undertaken inconsequence of the racemisation phenomena which were observed byone of us (Wren, Trans., 1909, 95, 1583, 1593) in connexion with thestudy of I-benzoin and its derivatives. I-Benzoin, which is preparedfrom magnesium phenyl bromide and I-mandelamide (McKenzie andWren, Trans.,'1908, 93, 312), has [aID - 119O in acetone solution, andundergoes complete racemisation with great readiness in the presenceof alkali. The interpretation was suggested that the isomeric changein question was probably of a keto-enolic character, the hypotheticalo-dihydroxystilbene being formed as an intermediate phase :C,H,*QH=OH C,H,*S*OH C,H,*QH OHC,H,*C*OH C,H,*COLaevorotatory.Inactive. Inactive.C,H,*CO -+ -+The racemisation of 2-benzoin methyl ether also proceeds with greatreadiness in the presence of alkali.I n accordance with this view, the hydrogen attached to the carbonatom of the :CH*OH group migrates to the adjacent carbonyl-oxygenatom :C,H,*FEC*OHC&,*CO "3 fDesmotropic change of this nature is, however, impossible if thecarbonyl group in I-benzoin is displaced by the CRR-OH group, atransformation which can be effected by the application of Grignard'sreaction to kbenzoin. We find accordingly that optically activeglycols of the types :C,H,* CH( OH) CRR OH and C,H, CH( 0 H) *CRR'* OHdo not lose their activity in the presence of alkali.The tripheny474 McKENZIE AND WREN: OPTICALLY ACTIVE GLYCOLSglycol, obtained from methyl Z-mandelate and magnesium phenylbromide, has [aID +221.3' in acetone solution, and is perfectly stableeven when boiled with N/lO-alcoholic potash for thirty minutes.Similarly, the diphenylethyl glycol, obtained from I-benzoin andmagnesium ethyl iodide, retains its activity unchanged during twenty-five hours at the ordinary temperature when dissolved in N/10-alcoholicpotash, whereas I-benzoin methyl other, under the same conditions, isracemised completely within five minutes.The convereion of methyl I-mandelate, a highly active lsevo-rotatory compound with [a], - 236' in carbon disulphide solution(Wren, Zoo.cit.), into the highly active dextrorotatory triphenylglycol, referred to above, suggested the possibility of a Waldeninversion having occurred in this change. In order to obtain furtherevidence on this point, the action of magnesium phenyl bromide onI-benzoin was examined, when it was found that the resulting glycolwas dextrorotatory and identical with the product from methylI-mandelate. There is thus no evidence of a Walden inversion ineither of these actions, and i t is accordingly proposed to designate thedextrorotatory glycols, derived either from methyl I-mandelate or fromI-benzoin, as I-compounds.Desyl chloride has not yet been obtained in an optically active form,and we therefore treated Lbenzoin with thionyl chloride, in the hopeof obtaining an interesting compound in which the displacement ofthe chlorine by the hydroxy-group might be studied.Unfortunately,the product of the action was inactive desyl chloride. The displace-ment by the chlorine atom of the tertiary hydroxy-group i n the activeglycols, which are described in this paper, has not, so far, beenattempted, since the action both of thionyl chloride and of fuminghydrochloric acid on inactive triphenylethylene glycol caused theelimination of one molecular proportion of water with the formationof triphenylvinyl alcohol. Now Tiffeneau (Compt. rend., 1908, 146,29) has found that the latter alcohol is also formed from triphenyl-ethylene glycol by means of sulphuric acid; this behaviour is,however, abnormal, the researches of Tiff eneau showing that theelimination of water from the glycols of the type :Ar GI1 (OH) CRR'.OHresults in other cases in the formation of aldehydes of the type :ArRR'C CHO.A further point arose in connexion with the interaction of I-benzoinand magnesium methyl iodide, Whilst the former compound containsonly one asymmetric carbon atom, the carbon atom of the carbonylgroup becomes asymmetric during this action, so t h a t the formatioDERIVED FROM L-BENZOIN AND FROM METHYL L-MANDELATE. 475of two isomeric laevorotatory glycols, each one of which contains twoasymmetric carbon atoms, is theoretically possible :?GH5H-C-OH H-C-OH1 and OH-$-CH, CH,-F-OHCiP5 ‘6=5These glycols are not, of course, enantiomorphously related, andmight be expected to be produced in unequal amounts, Only oneisomeride was obtained, Again, when r-benzoin was acted on bymagnesium methyl iodide, only one of the two possible inactiveglycols was isolated, and it was obvious from the yield that the otherisomeride could have been present only in small amount, or notat all.The only glycol of the type R*CH(OH)*CRR*OH known up to1904 was the triphenylethylene glycol described by Gardeur (Bull.Acad.roy. BeEg., 1897, [iii], 34, 67). Acree (Ber., 1904, 37, 2753)has shown that similar glycols are obtained by the aid of Grignard’saction (compare also Tiffeneau and Dorlencourt, Ann. Chim. Phys.,1909, [viii], 16, 237, and other papers). These compounds are alloptically inactive.The Grignard action as applied to an ester of anoptically active hydroxy-acid was studied for the first time byP. F. Frankland and Twiss (Trans., 1904, 85, 1666), who preparedd-aa88-tetraphenylerythritol by the interaction of methyl d-tartrateand magnesium phenyl bromide. This ditertiary glycol is charac-terised by the high dextrorotation which it exhibits when contrastedwith that of the tartrate from which it is derived.I n the course of the large amount of work carried out by manychemists on the connexion between unsaturated or negative groupsand optical activity, the abnormal effects produced by the phenylgroup have been repeatedly observed. It is, therefore, not surprisingthat such effects should be encountered with the compounds which arenow described.Purdie has shown that the substitution of the hydrogen atom ofthe alcoholic hydroxy-groups in the optically active lactic, malic, andtartaric acids (or their esters) by an alkyl group causes a very pro-nounced rise of optical activity.Vhen a similar displacement iseffected in E-mandelic acid, no such effect is observed (McKenzie,Trans., 1899, 75, 753).C,H,-CH(OH)*CO,Me,has [a], -236’ in carbon disulphide solution (Wren, Zoc. cit.),whereas methyl I-phenylmethoxyacetate, C,H,*CR(OMe)*CO,Me (seeexperimental part) has [a], - 1 0 1 . 7 O in the same solvent. The com-Again, methyl I-mandelate4'76 McKENZIE AND WREN : OPTICALLY ACTIVE QLPCOLSparison between the effect on rotatory power which is brought aboutby the displacement of the hydroxy-group in kmandelic acid (or itsmethyl ester) by the methoxy-group, and a similar displacement inaliphatic hydroxy-acids (or esters), leads to the conclusion that thegreat difference between the two cases is due to t h e influence exertedby the phenyl group.When E-triphenylethylene glycol, OH*CHPh*CPb,*OH, is alkylatedby nieans of silver oxide and methyl iodide, only one of the twohydroxy-groups undergoes methylation.It is shown that the mono-methoxy-derivative, obtained in this manner, has the formulaOMe*CHPh*CPh,*OH,and not OH*CHPh-CPh,*OMe, and that the introduction of themethyl group into the molecule of the triphenyl glycol lowers thevalue for the specific rotation to + 185.3' in acetone solution.I n a recent exhaustive study of the influence of constitution on therotatory power of optically active compounds, Rupe (Annalen, 1909,369, 311 ; compare also ibid., 1903, 327, 157) points out that theI-menthyl esters of saturatttsd acids, derived from phenylcinnamic acids,possess a higher degree of optical activity than the correspondingesters of the unsaturated acids.The normal effect which Rupeobserved in this particular group appears to be that negative groupslower the rotatory power iu a pronounced manner. Thus, in I-menthyl/3-phenylcinnamate, CPh2:CH*COf*CloH19, with [a],, - 37-92' inbenzene solution, the optical effect caused by the asymmetricmenthyl group is influenced by the electronegative character of twophenyl groups and of one double linking.When one of these negativefactors is eliminttted, for instance, the double linking, the rotatorypower is enhanced, thus I-menthyl PP-diphenylpropionate,CHPh,*CH,*CO,*C,,H,,,has [a], - 61.72' in benzene solution, Now this behaviour isopposed to the deduction from work of Tschugaeff, Haller, Walden,and others, and, indeed, also from Rupe's own work on this subject,namely, t h a t unsaturated groups (phenyl group, double linking) tendto enhance optical rotation. For example, Rupe finds tbat I-menthylcrotonate has [.ID - 91-06O in benzene solution, whereas I-menthyln-butyrate has [a], -70.56", the elimination of the double linkinglowering the rotatory power in this case. Again, Frankland andSlator (Trans., 1903, 83, 1349) show that d-tartranilide has a higherdextrorotation than has d-tartramide, and that aromatic groups raisethe rotation of the latter compound very considerably.Finallyanother example of the same effect, and a very striking one, isthe comparison between p-hydroxyphenyliminocamphorDERIVED FROM L-BENZOIN AND FROM METHYL L-AT ANDELATE. 47 7with [alD +1363O in chloroform solution, and the product of itsCH*NH*C,H,*OHreduction, p-hy droxy phenylaminocamphor, C,H,,< I co 9wit,h [a]= + 83' in chloroform solution (Forster and Thornley, Trans.,1909, 95, 942).I n the course of his important work in this field, Rupe emphasisesthe depression in rotation exerted by the displacement of a methyl bya phenyl group, thus :[alD i nCH,:CMe'CO,H ........................... - 91.76"CH,:CPhCO,H ..........................63.03CMe,:CH*CO,H .......................... 88.60Z-Menthyl esters of the acids. Leiizene soliition.CMePh:CH-CO,H ........................ 65-89CPh,:CH*CO,EI ........................... 37'92These figures are quoted here for comparison with the valuesobtained for tho glycols :[alu inOH*CHPh'CMe,'OH .................. - 21 '6'OH'CHPh'CMePh'OH ................. + 34-0OH*CHPh*CEtPh*OH ................. +27'4OMe'CHPh'CPh,'OH .................. + 185.3OH'CHPh*CPh,*OH .................. 4- 221 '3The latter compounds are, of course, of a very different type fromthose of Rupe, and it is of interest that the effect of the phenyl groupis so pronounced.EXPERIMENTAL.Z:Glycols. acetone solution.Action of Magnesium Methyl Iodide on 1-Benzoin.The Grignard reagent, prepared from 1.4 grams of magnesium(4 mols.), 7-8 grams of methyl iodide (4 mols.), and 50 C.C.of ether, wascooled in ice-cold water, and 3 grams of finely-powdered Lbeneoin(1 mol.) were added in small quantities at a time. The action wasvigorous, After the mixture had been boiled gently for three hours,it was decomposed in the usual manner by ice and dilute sulphuricacid, and the liberated glycol extracted with ether. After drying theethereal solution and removing the ether, the resulting viscid, brownproduct solidified when stirred with a small quantity of carbondisulphidb. It was purified by crystallising from carbon disulphideseveral times, 10 C.C. of solvent being used on each occasion, until itsrotation was con stant.l-ap-Dihydroxy-a/3-&phenyZpopune, OH CHPh- CMePh OH, separ-ates from carbon disulphide as a colourless, amorphous solid, andmelts at 81-82O.It is very readily soluble in boiling carbondisulphide, and sparingly so in the cold solvent. It is veryreadily soluble in cold benzene, methyl alcohol, ethyl alcohol, ether, o478 McKENZIE AND WREN: OPTICALLY ACTIVE GLYCOLSacetone, and less so in cold carbon tetrachloride.in boiling light petroleum (b. p. 60-80°), separating on cooling.is very sparingly soluble in water.cold concentrated sulpburic acid.It dissolves readilyItIt gives a violet coloration withFor analysis, the glycol was dried a t 78O until constant in weight :0.11'75 gave 0.3383 CO, and 0.0743 H,O.C,,H,,O, requires C = 78.9 ; €3.= 7.1 per cent.The specific rotation was determined in acetone solution, the glycolC= 78.5 ; H= 7.1.having been dried at 78" :l = 2 , ~ = 1 . 6 4 8 , a:'' +1.12O, [u]? +34*Oo.No racemisation was observed with the solution of the glycol inalcoholic potash.Action of Magnesium Methyl Iodide on r-Benzoin.Since a second asymmetric carbon atom is generated by the actionof magnesium methyl iodide on benzoin, the behaviour of r-benzoinwas studied in order to find out if only one glycol is formed. Theexperiment indicated that, if an isomeric glycol is produced, i t can bepresent only in small amount.Twelve grams of r-benzoin were gradually added to the Grignardreagent, prepared from ,5.5 grams of magnesium, 30.3 grams ofmethyl iodide, and 100 C.C.of ether. The crude product, obtained asin the previous experiment, amounted t o 12.5 grams. After onecrystallisation from carbon disulphide, the glycol melted at103.5-105.5°, and the yield was 11.5 grams. After a secondcrystallisation from the same solvent, the compound was pure.Inactive up-dihydroxy-up-diphenylpropane separates from carbondisulphide in colourless needles, and melts at 103*5-104*5°. It is lesssoluble in carbon disulphide or light petroleum than is its 2-isomeride.When dried in a vacuum over sulphuric acid at the ordinary tempera-ture, it retains persistently small quantities of solvent. For analysis,it was accordingly dried at 78O until constant in weight :0-1223 gave 0.3520 CO, and 0.0764 H,O.C15H1602 'requires C = 78.9 ; H = 7.1 per cent.The preparation of this glycol has also been described by Tiffeneauand Dorlencourt (Ann.Chim. Phys., 1909, [viii], 16, 237), who givethe melting point as 104O. There is also no evidence in the workrecorded by these authors of the formation of a second isomeride.C = 78.5 ; H = 7.0.Action of Magnesium Ethyl Iodide on 1-Benzoin.Four grams of I-benzoin (1 mol.) were treated with magnesium ethyliodide, obtained from 1.8 grams of magnesium (4 mols.), 11.8 grams oDERIVED FROM L-BENZOIN AND FROM METHYL L-MANDELATE. 479ethyl iodide (4 mols.), and 50 C.C. of ether. The crude diphenylethylglycol (4.3 grams) was crystallised from successive small quantities ofcarbon disulphide.The first crop obtained melted sharply, and, whendried at 78' until constant in weight, gave the following value for itsspecific rotation in acetone solution :l = 2, C = 1.288, aD + 0*64O, [=ID + 24.8'.After a second crystallisation, the melting point was the sameas before, but the value for the specific rotation determined asbefore was somewhat higher. The concentration, however, wasgreater :I = 2, c = 4,674, a:" + 2.56', [a]:' + 27.4'.The value obtained after another crystallisation was practicallyidentical with this.I-ap-Dihydroxy-ap-d~phe~ ylbutane, OH*CHPh* CE tPh* OH, separatesfrom carbon disulphide in colourless prisms, capped by pyramids,and melts at 96-5-975'. It is very readily soluble in boiling carbondisulphide, and sparingly soluble in the cold solvent. It is solublewith difficulty in light petroleum or water.It is easily soluble in coldacetone, ethyl alcohol, benzene, chloroform, or ether, and less soin carbon tetrachloride. I t s solution in cold concentrated sulphuricacid is magenta-coloured, and becomes green on heating.For analysis, it was dried a t 78':0.1509 gave 0,4366 CO, and 0-1018 H,O.The value for the specific rotation in acetone solution is + 27.4", asC = 78.9 ; H = '7.5.C,,H,,O, requires C = '79.3 ; H = 7.5 per cent.given above. I n ethyl-alcoholic solution :I = 2, C = 2.883, ctF5 + 1-13', + 19.6'.I n chloroform solution :The corresponding inactive compound has been prepared by Acree(Amer. Chem. J., 1905, 33, 193).When the 1-glycol was dissolved in ethyl-alcoholic potassiumhydroxide, no racemisation was detected.Thus 0.2977 gram, whenmade up t o 10 C.C. in cold alcoholic potash (0-104N), had a,, + 1.20' ina 2-dcm. tube. This value did not alter during twenty-five hours atthe temperature of the laboratory.1 = 4, c = 2.044, + 0*26O, [a]$'5 + 3.2'.It melts at 115-116'.Action of Mclgnesizcm Phenyl Bromide on Methyl 1-Madelate and on1- Benzoin.A solution of methyl I-mandelate (8 grams) in ether (50 c,c.) wassiphoned within an interval of eight minutes into a solution of theGrignard reagent, prepared from magnesium (4.6 grams), bromobenzen480 McKENZIE AND WREN: OPTICALLY ACTIVE GLYCOLS(30-3 grams) and ether (50 c.c.). After the vigorous action hadsubsided, the mixture was boiled gently for two hours and thendecomposed in the usual manner.The resulting brown solid wascrystallised several times from methyl alcohol until i t s rotation wasconstant.For analysis and determinations of its specific rotation, tihe glycolwas dried a t 100' until constant in weight. It retains methylalcohol with considerable obstinacy, determinations indicating,however, that the alcohol is not present in the air-dried productin definite molecular proportions.l-up-I)i~ydroxy-uPP-~ri~?~~~~yZet?~ane (tripheny lethy lene glycol),OH*CHPh*CPh,*OH,separates from methyl alcohol in colourless needles, and, after beingdried at loo', melts a t 128-129', the meltiug point of the inactiveisomeride being 167',according to Acree (Ber., 1904, 37, 2762).Theactive glycol is readily soluble in boiling methyl alcohol. It may alsobe crystallised from light petroieum, in which it is sparingly soluble.It is practically insoluble in water, but dissolves with ease in coldacetone, benzene, ether, or chloroform. I t gives an emerald-greencoloration when beated with concentrated sulphuric acid ; the solutionbecomes colourless in presence of excess of water, and a yellow tintappears when an excess of alkali is added. These colour reactions arealso exhibited by triphenylvinyl alcohol :0.1719 gave 0.5230 CO, and 0.0960 H20.. C=83-0; H=6*2.C,,,H,,O, requires C = 82.7 ; H = 6.3 per cent.A determinatiou of its specific rotation in acetone solution gave theresult :I = 4, c = 1.0156, + 8*99*, [ u ] E ' ~ + 221.3'.Its rotation was also determined in chloroform solution :I = 4 , C = 1.3196, u: + 12-33', [u]: + 233.6'.It was of interest to find out if a dextrorotatory glycol would alsobe obtained by the interaction of I-benzoin and magnesium phenylbromide.Finely-powdered I-benzoin (3 grams) was accordingly addedgradually to the solution obtained from magnesium (1 gram), bromo-benzene (8.1 grams), and ether (60 c.c.), the Grignard reagent havingbeen cooled previously in ice-cold water. After the addition of thebenzoin, the mixture was boiled gently for ninety minutes. The glycolwas isolated as in the preceding experiment.0.1343 gave 0.4085 CO, and 0.0758 H20.C,,H,,O, requires C = 82.7 ; H = 6.3 per cent.The compound was identical with that obtained from methyI-mandelate, as shown by determinations of melting point and specificrotation made with it.On analysis :C = 82.95 ; H = 6.3DERIVED FROM L-BENZOIN AND FROM METHYL L-MANDELATE.481The action of ethyl-alcoholic potassium hydroxide m a s examined.I-Triphenylethylene glycol (0.8 gram) was boiled for thirty minuteswith 25 C.C. of 0.1121-alkali. A violet coloration appeared a t first,and, when the solution was shaken, this became reddish-brown.The mixture was poured into 200 C.C. of water, and the precipitatedglycol filtered and dried. Polarimetric examination in acetonesolution showed that the glycol had remained unracemised evenafter this drastic treatment with alkali.Action of Magnesium Methyl Iodide on Methyl l- Mandelate.A solution of methyl I-mandelate (7 grams) in &her (40 c.c.) wassiphoned within an interval of ten minutes into an ice-cold solution ofthe Grignard reagent, prepared from magnesium (4.4 grams), methyliodide (26.1 grams), and ether (50 c.c.).The crude product obtainedin the usual manner was an oil, which was dried and obtained crystal-line by being stirred with light petroleum. After two further crys-tallisations from light petroleum containing a little ether, the glycolwas obtained pure.1-up-Dihydroxy-aphertylisobutane, OH*CHPh*CMe,*OH, melts a t33-5-35', It gives an orange coloration with cold concentratedsulphuric acid, and the solution becomes strongly fluorescent whenwarmed :0.2657 gave 0.7000 CO, and 0.2029 H,O.I t s specific rotation was determined in acetone solution :C = 71.9 ; H = 5.5.C1,H1,O, requires C = 72.2 ; H = 8.5 per cent.I = 2 , ~=2*7352, - 1*18', [a]: - 21.6'.Action of Thionyl Chloride on 1-Benzoin and on Inactive Triphen$-ethylene Glycol.The action of thionyl chloride on I-benzoin was studied in the hopeof obtaining optically active desyl chloride, but racemisation occurredin the displacement of the hydroxy -group by chlorine.LBenzoin(3.2 grams) was covered with thionyl chloride (3.5 grams). Theevolution of hydrogen chloride began at the ordinary temperature,whilst the product gradually became liquid. After three hours, thetemperature was raised gradually from 15' to 55' during the course oftwo hours, when very little action appeared to take place.A t 55',hydrogen chloride was again evolved somewhat briskly, Thetemperature was then raised to 90'. The dark reddish-brown liquidbecame semi-solid when placed over soda-lime in a vacuum. Aftersome days, the specific rotation of the product in acetone solution was-9*7", but this activity may have been due t o a little unchange482 MCKENZIE AND WREN: OPTICALLY ACTIVE GLYCOLSbenzoin. After three crystallisations from ethyl alcohol, desylchloride, melting a t 66-68O, was obtained. This was quite inactivewhen examined polarimetrically.Thionyl chloride (28 grams) was added to inactive triphenylethyleneglycol ( 5 grams) prepared from r-benzoin according to Acree (Zoc. cit.).The glycol dissolved within fifteen minutes at the ordinary tempera-ture, the red solution slowly evolving hydrogen chloride.Thetemperature was raised slowly to the boiling point of thionyl chlorideduring one hour, and maintained at this point for two hours longer.After drying over soda-lime in a vacuum, the resulting solid wascrystallised twice from light petroleum (b. p. 60-80O). The compoundobtained in this manner was quite free from chlorine, and its meltingpoint (135-136') and analysis showed that it was triphenylvinylalcohol :0.1654 gave 0.5352 CO, and 0.0889 H,O.C,,H,,O requires C = 88.2 ; H = 5.9 per cent.Triphenylvinyl alcohol has been prepared by Delacre (Bull. Soc.chim., 1895, [iii], 13, 857 ; compare also Saint-Pierre, Bull. SOC. chim.,1891, [iii], 5, 292 ; Gardeur, Bull.Acad. roy. Bely., 1897, [iii], 34, 67),who employed the Friedel-Crafts' reaction with trichloroacetyl chlorideand benzene. The proof, however, that the compound in question wastriphenylvinyl alcohol, CPh,:CPh*OH, and not triphenylethanone,CHPh,-COPh, was supplied by Biltz (Ber., 1899, 32, 660). Anschutzand Forster (Annalen, 1909, 368, 89) have observed recently thattriphenylvinyl alcohol is formed by the interaction of acetylmandelylchloride, benzene, and aluminium chloride, whereas the formation ofbenzoin acetate might have been expected. The same authors alsoprepared the vinyl alcohol from desyl chloride, benzene, and aluminiumchloride.The action of fuming hydrochloric acid' on inactive triphenylethyleneglycol is similar to that of thionyl chloride.Three grams of theglycol were added to 40 C.C. of aqueous hydrochloric acid, saturated a t0". After several weeks in a stoppered bottle a t the ordinarytemperature, the product was diluted with water, and the solidcrystallised twice from ethyl alcohol. It melted at 135*5--136*5O, andwhen it was mixed with an equal amount of the glycol, obtained bythe aid of thionyl chloride, the melting point did not change.C = 88.2 ; H = 6.0.Inactive p-Hydrox?/-a-methoxy-app-tripl~enylethane.Methylation of Inactive Triphenylethylene Glycol,-Four grams of theinactive glycol (1 mol.) were added to 9.6 grams of silver oxide(3 mols.), 24 grams of methyl iodide (12 mols.), and 35 C.C. of acetone.The mixture was boiled gentlyfor six hours and filtered.The solvenDERIVED FROM L-BENZOIN AND FROM METHYL L-MANDELATE. 483was removed from the filtrate, and the product again alkylated withhalf the above quantities of oxide and iodide. The product obtainedin this manner was crystallised once from much light petroleum (b. p.60-80°), and then twice from methyl alcohol :0.1166 gave 0.3557 CO, and 0-0675 H20. C = 83.2 ; H = 6.5.0.3284 ,, 0.2392 AgI ; OMe = 9.6.C,,H,,O, requires C = 82.9 j H = 6.6 ; OMe = 10.2 per cent.This compound is obviously a monomethyl derivative of triphenyl-ethylene glycol. The following experiments showed that it was/3 - hydroxy - a - methoxy - aP/3 - triphenylethane, and not a - hydroxy-P-methoxy-a/3P-triphenylethane.Action of Nagnesiurn Phenyl Bromide on Inactive Benzoin -&ethylEther.-The Grignard reagent, prepared from 0.4 gram of magnesium(1.3 mols.), 2.5 grams of bromobenzene (1.3 mols.), and 14 C.C.ofether, was boiled gently for two hours with 2.7 grams of inactivebenzoin methyl ether (1 mol.). The product, obtained in the usualmanner, was a crystalline solid, and amounted to 3.2 grams. Aftertwo crystallisations from much ethyl alcohol, P-hydroxy-a-methoxy-aPP-triphenylethane, melting at 139O, was obtained. Its identity withthe compound prepared from triphenylethylene glycol was shown bythe melting point of a mixture of the two, and by the analysis :0.1818 gave 0.5510 GO, and 0*1080 H,O.Action of Magnesium Pheny2 Bromide on Inactive Methyl Phenyl-C = 82.65 ; H = 6.6.C21H2002 requires C = 82.9 ; H = 6.6 per cent.methoayacetate.-Inactive phenylmethoxpacetic acid,C,H,*CH(OMe)*CO,H,was prepared by the interaction of sodium methoxide and methylphenylchloroacetate.It was isolated by the aid of its sparinglysoluble sodium salt (compare McKenzie, Trans., 1899, 75, 753), andthen esterified by means of methyl alcohol and sulphuric acid.Eighteen grams of methyl ester, boiling at 118-1 19O/8 mm., wereobtained from 20 grams of acid.Five grams of the methyl ester (1 mol.), dissolved in 40 C.C. ofether, were added to a solution of 2 grams of magnesium (3 mols.) in13.2 grams of bromobenzene (3 mols.) and 40 C.C. of ether within aninterval of six minutes. The crude product obtained by decomposi-tion of the additive compound was crystallised twice from ethylalcohol.The yield of pure methoxy-glycol amounted to 5.4 grams.It was identical with the products obtained from triphenylethyleneglycol and benzoin methyl ether respectively.Inactive P-h y drox y-a- me t hox y-app- triphen, y Zet hane,OMe*CHPh CPh,. OH,melts at 138*5-139*5°. It is fairly soluble in boiling ethyl alcohol,VOL. XCVII. K 484 McKENZIE AND WREN : OPTICALLY ACTIVE GLYCOLSand sparingly so in the cold. It crystallises from ethyl alcohol incolourless prisms. It may also be crystallised from light petroleum(b. p. 60-80"), in which it is fairly soluble on heating. It is fairlysoluble in cold ether, easily so in cold acetone or chloroform, somewhatless readily so in cold carbon tetrachloride, and sparingly soluble inwater.It gives a colour reaction with concentrated sulphuric acidsimilar to that of I-triphenylethylene glycol.1-P- Hydroxy-a- methox y- a/3/3-triphenyZethane.Action o j Magnesium Phenyl Bromide on Methyl I- Phenylmethoxy-ctcetate.-Methyl I-mandelate was alkylated with silver oxide andmethyl iodide, the mixture of methoxy-ester and unchanged methylmandelate saponified, and the resulting acid converted into sodiumsalt. Since sodium Lphenylmethoxyacetate is sparingly soluble inwater (McKenzie, Zoc. cit.), it can be separated readily from the sodiummandelate present.I-Phenylmethoxyacetic acid, obtained from the sodium salt, had[u]" - 150.1O for c = 3.597 in ethyl-alcoholic solution, the value quotedpreviously being [a]:" - 150*0° f o r c = 6.7656.I-Phenylmethoxyacetic acid (10 grams) was converted into its methylester by the Fischer-Speier method, using methyl alcohol and sulphuricacid. The yield was 8.5 grams.Methyl l-phenylmethoxyacetate, C,H,-CH(OMe)*CO,Me, is a colourlessoil, which boils at 1175-1 1 S0/8 mm.:0.2885 gave 0.6988 CO, and 0.1775 H,O.C,,H,,O, requires C= 66.6 ; H = 6.7 per cent.The following determinations of specific rotation of this ester invarious solvents were made for comparison with the activity of methylI-mandelateC = 66.1 ; H = 6.9.In carbon disulphide solution :I = 1, c = 2.93, uF5 - 2-98', - 101.7".In acetone solution :I = 4, C = 2,6948, CZ: - 10*38", [a,]: - 96.3'.In benzene solution :I = 4, c = 2.0968, a: - 8.324 [a]: - 99.2'.A solution of methyl I-methoxymandelate (5 grams, 1 mol.) in ether(40 c.c.) was siphoned with constant shaking within an interval ofsix minutea into a solution of the Grignard reagent (3 mols.) preparedfrom magnesium (2 grams), bromobenzene (13.2 grams), and ether(40 c.c.).Towards the end of the addition a bulky precipitateseparated, which became grey on warming. The mixture was heatedfor two hours. The crude product resulting from the action amounteDERIVED FROM L-BENZOIN AND FROM METHYL L-MANDELATE. 485t o 9 grains. After two crystallisations from ethyl alcohol, thecompound is pure.I - P - N y c l r o x ? / - a - n t e t / i o x ? / - a ~ ~ - t ~ ~ ~ r ~ ~ ~ ~ ~ ~ e t ~ i a ~ e , OMe*CHPh*CPh,*O€l[,separlttes from ethyl alcohol in colourless needles, grouped in rosettes,and melts at 143-144'.Its colour reaction with concentratedsulphuric acid is similar to that of the inactive isomeride :0.1459 p v e 0.4423 CO, and 0.0852 H20.0.239'7 ,, 0.1742 AgI. OMe = 9.6.Its specific rotation was determined in a number of solvents.C = 82.7 ; H = 6.5.C,,H,,O, requires C = 82.9 ; H = 6.6 ; OMe = 10.2 per cent.I nacetone solution :I = 1, ~ = 5 * 4 2 8 , a: + 10*06O, [u]F + 185.3'.I n chloroform solution :I = I, C = 4.579, ag + 10.76', [a];' + 235.0'.In benzene solution :I = 1, C = 3.667, uk + 10*8', [a]: + 294.5'.I n ethyl-alcoholic solution :I = 4, c = 1.0176, a: + 6-77', [a]: + 166.3'.The glycol is sparingly soluble in cold ethyl alcohol. It may also becrystallised from methyl alcohol or light petroleum (b. p. 60-80'). Itis easily soluble in cold acetone, chloroform, carbon tetrachloride,ether, or benzene, and sparingly so in water.Methylat ion of 1- Triphen ybtlby Zene Glycol. -Seven grams of I- triphenyl-ethylene glycol (1 mol.) were heated with 11.2 grams of silver oxide(2 mols.), 42 grams of methyl iodide (12 mols.), and 10 C.C. of acetoneduring seven hours. The alkylation was found, however, to beincomplete even after a second alkylation under the same conditionsas before. After a third alkylation, the product mas crystallised untilits rotation was constant, four crystallisations from light petroleumbeing necessary. The glycol obtained in this manner was identicawith I-P-hy droxy -a-me thoxy-aPP- triphenyle thane described above. Itmelted at 143-144', and its identity was confirmed by the mixedmelting-point method. A determination of its specific rotation inacetone solution gave the result :I=3, ~=2*885, a: + 10.68', [u];' + 185.1'.No racemisation was detected with the solution of this glycolin alcoholic potash. 0.254 Gram was made up to 25 C.C. with0*168N-alkali. This solution gave aD + 6 * 8 4 O , a value which had notchanged after twenty hours at the ordinary temperature.K K 486 HARDING AND HAWORTH : SYNTHESIS OF A~-CYCLOPENTENE-The bulk of the expense of this investigation has been defrayed bygrants from the Government Grant Committee of the Royal Societyand from the Research Fund Committee of the Chemical Society, forwhich we desire to make this grateful acknowledgment.BIRKBECK COLLEGE,LONDON, E.C

ISSN:0368-1645    

DOI:10.1039/CT9109700473

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

486 HARDING AND HAWORTH : SYNTHESIS OF A~-CYCLOPENTENE-1,111.- The Synthesis of A1-cycloPe7?,teneaeetic Acid and1 - f ~ ~ t ~ ~ y ~ - A ~ - c y c l o h e x e n e - 3-acelie A c d .By VICTOR JOHN HARDING and WALTER NORMAN HAWORTH.A SHORT time ago, Harding, Haworth, and Perkin (Trans., 1908, 93,1943) published an account of a series of experiments on the constitu-tion and synthesis of 1 -methylcycZohexylidene-4-acetic acid. I n thecourse of this investigation a convenient method for the preparationof unsaturated cyclic acids was discovered, and the present authorshave continued tho work in this direction.In the previous communication (Zoc. cit.) it was shown that the con-densation of ethyl sodiocyanoacetate with cyclohexanone and 1-methyl-cyclohexan-4-0110 gave products which, on hydrolysis, yielded deriv-atives of acetic acid containing the double bond in the ring.In the caseof 1 -methylcycZoheuan’-4-one, 1 -met hyl-A3-cycZohexene-4-acetic acid (I)(1.1 (11.)is produced. The isomeric 1-methylcyclohexylidene-4-acetic acid (IT),an acid first prepared by Perkin and Pope (Trans., 1908, 93, 1075;compare also Wallach, Annalem, 1909, 365, 266), is not formed in anyappreciable quantity, The products of the condensation of cyclo-hexanone and ethyl sodiocyanoacetate were also investigated, and itwas shown that in this case a mixture of the two isomeric acids :was produced (Harding, Hamorth, and Perkin, Zoc. cit., p. 1961), thelatter acid being present, however, only in small amount.This fact is worthy of note, since there is no evidence of the forma-tion, even in traces, of l-methylcyclohexylidene-4-acetic acid during thecondensation of 1 -methylcycZohexan-4-one and ethyl sodiocyanoacetate.It is clear that in the latter case the cyano-ester obtained from thecyclic ketone and ethyl cyanoacetate, whether piperidine or sodiumethoxide is used as the condensing agent, consists almost entirely oACETIC ACID AND 1-METHYL-A2-CYCLOHEXENE-3-ACETIC ACID 487the derivative with the double linking in the ring.This was furtherproved by the observation that, when treated with methyl iodide orbromoacetophenone, substitution derivatives were readily formed (Zoc.cit., p. 1958) in almost quantitative yield. In the present communica-tion the authors have extended their investigation to cyclopentanoneand inactive 1 -methylcyclohexan-3-one.The condensation products of cyclopentanone are particularly inter-esting, because in this case the resulting ester is solid, whereas in thecase of six-membered rings it is a liquid.This fact has enabled theauthors to remove all doubt as to the nature of the reaction, since theyhave found that, prepared either by means of ethyl sodiocyanoacetateor the free ester and piperidine, the cyano-ester obtained is the same.cycZoPentanone condenses readily with ethyl sodiocyanoacetate withthe formation of ethyl a-cyano-Al-cychpentene-1-acetate,FH"'"SC*CH(CN)*Co,Et, CH,* CH,and a-cyano-A*-cyclopentene-1-acetic acid. The methyl ester is obtainedin a similar manner from methyl sodiocyanoacetate and cyclopentanone,and is also crystalline.Both these cyano-esters may be methylatedby treatment with sodium methoxide and methyl iodide. a-Cyano-A1 - cyclopentene - 1 - acetic acid decomposes on distillation underdiminished pressure with elimination of carbon dioxide and formationof Al-cyclopenteneacetonitrile,YH2-' H>C*CH,= CN,CH,*CH,from which, by digestion with alcohol and sulphuric acid andsubsequent hydrolysis, Al-cyclopen teneacet ic acid is obtained.This acid had previously been prepared by Wallach (Annalen, 1902,323, 159, and 1906, 347, 324), who obtained it by the condensationof cyclopentanone and ethyl bromoacetate in presence of zinc, andsubsequent elimination oE water from the hydroxy-ester by means ofpotassium hydrogen sulphate.When the hydroxy-ester is treatedwith hydrobromic acid it yields ethyl 1-bromocyclopentane-1-acetake,>CBr *CH,*CO,Et, $!H,*CH,CH,*CH,and t h i s is decomposed by dimethylaniline with the formation of ethylAl-cyclopenteneacetate. I n order to remove all doubt as to the con-stitution of this acid, the authors have, with the kind permission ofProf. 0. Wallach, prepared the isomeric c~clopentylideneacetic acid(IV) by digesting the /3-hydroxy-acid (111) with acetic anhydride :>C( OR)-CH,* C0,H 8::: E z > C : CH-CO,H.QH,-CH2CH,-CIH488 HARDING AND HAWORTH : SYNTHESIS OF A~-CYCLOPENTENE-The latter acid yields cyclopentanone on oxidation with alkalinepermanganate, and its formation by the above method is exactlysimilar to that of 1 -methylcycZohexylidene-4-acetic acid from I-methyl-4-hy droxycyclohexane- h c e t ic acid.The condensation of 1 methylcyclohexan-3-one with ethyl sodio-cyanoacetate proceeds quite readily, with the formation of an esterwhich may have either of the following constitutions :lMe T.-f-!H cH>C*CH(CB).C02Etand it has not yet been found possible to decide between those, but inthis paper we assume that it has the former.The cyano-acid obtainedfrom the hydrolysis of this ester loses carbon dioxide when distilledunder diminished pressure, with the production of 1 -methyl-A2-cyc20-hexene-3-acetonitrile.When this nitrile is hydrolysed it yields the corresponding acid,which was found to melt at 25". Wallach (Annaleiz, 1901, 314, 157 ;1906, 347, 340), by the condensation of 1-methylcyclohexan-3-one withethyl bromoacetate in presence of zinc, and the subsequent elimina-tion of water from the hydroxy-ester, obtained a liquid acid, the amideof which he first found to melt at 150', but in a later paper he gives353-154' as the true melting point.The amide of the acid whichwe have prepared was found to melt at 150", but we do not thinkthere can be any doubt as to the identity of the two acids. Thepossibility that this acid contains the ethylenic linking outside thering, and is, therefore, 1 -methylcycZohexylidene-3-acetic acid, may bedismissed, since the cyano-ester, from which it is produced readily,gives on treatment with sodium methoxide and methyl iodide a methyl-substituted derivative which passes on hydrolysis and distillation intothe corresponding nitrile (V).This nitrile can be further hydrolysed only with difficulty t o thecorresponding a-1-methyl-A2-cyczohexene-3-propionic acid (VI), which isa liquid.The authors have also attempted to prepare alicyclic phenyl-acetic acids by condensing cyclohexanone and 1-methylcyclohexan-4-one with phenylucetonitrile in the presence of sodium ethoxide. Thephen ylacetoni triles ACETIC ACID AND I -METHY L-A2-CY CLOHEXENE-3-ACETIC ACID 489are easily obtained in this way, but, so far, no method by which theycan be hydrolysed to the corresponding acids has been found. All-attempts to hydrolyse these nitriles resulted in the production of theoriginal ketone and phenylacetic acid.EXPERIMENT A L.a-Cyano-A1-cyclopenteneacetic Acid,yH2-cH>C*CH(CN)*C0,H, CH,*CH2and its Ethyl Ester.I n preparing ethyl a-cyano-A1-cyclopenteneacstate, ethyl cyano-acetate (56 grams) was added to a solution of sodium (1 1.5 grams) i nalcohol, and, after the soparation of the white sodium derivative,cyclopentanone (42 grams) was then introduced.The sodium deriv-ative rapidly dissolved, leaving a clear solution, which was heated foran hour on the water-bath, and the yellow solid which had separatedwas dissolved in water and decomposed by dilute hydrochloric acid.The precipitated oil was extracted with ether, the ethereal solutionwashed with water, and then shaken with sodium carbonate, dried,and evaporated.The residual oil on fractionation yielded a smallquantity of cyclopentanone, and then ethyl a-cyano-Al-cyclopentene-acetate distilled over at 163-165'115 mm. as a viscid, colourless oilwhich, when pure, solidified in colourless needles, melting at 54' :0.1230 gave 0.3021 CO, and 0.0811 H20. C=67.0 ; H = 7.3.0.1373 ,, 9-1 C.C. N, at 16' and 761 mm. N=7-7.C,oHl,O,N requires C = 67.0 ; H = 7.3 ; N = 7.8 per cent.The sodium carbonatie extract on acidifying yielded an oil which wasextracted with ether, and, after evaporation of the solution, the residuerapidly solidified. The solid acid was pressed on porous porcelain, andthen recrgstallised from benzene, or, better, from anhydrous ether,from which it separates in large, colourless prisms, melting a t 129' :0.1301 gave 0.3029 GO, and 0,0682 H,O.0-1020 ,, 8.0 C.C.N, at 1 8 O and 760 mm. N=9.1.a-Cya~o-A1-cyclopenteneacetic acid is soluble in ether, benzene, ethylacetate, or ethyl alcohol, but only sparingly so in light petroleum. Itdissolves in dilute potassium hydroxide, and the solution soon cloudson warming, owing to the separation of cyclopentanone by decom-position of the acid. The potassium salt is sparingly soluble inconcentrated alkali.The following is an alternative method of preparation with the aidof piperidine :C = 63.4 ; H = 5.8.C,H,O,N requires C = 63.5 ; H = 5.9 ; N = 9.3 per cent490 HARDING AND HA WORTH : SYNTHESIS OF A~-CYCLOPENTENE-Equimolecular quantities of cyclopentanone and ethyl cyanoacetate.were mixed with a few drops of piperidine, and the whole kept coldfor four hours; the condensation was completed by warming on thewater-bath for an hour. The product was cooled and poured intowater, when ethyl a-cyano-A1-cyclopentenelzcetate separated as abrown, crystalline solid, which was collected, freed from oil byporous porcelain, and recrystallised from dilute ethyl alcohol, fromwhich it separates in tufts of fine, silky needles, melting at 53-54',the yield by this method being almost quantitative.Preparation of Methyl a-Cyano-Al-cyclopenteneacetate,yH2-CH>C*CH(CN)*C02Me.CH,*CH,(a) With Sodium Methoxide.-cycZoPentanone (8 grams) was addedto methyl sodiocyanoacetate (1 2 grams), prepared in methyl-alcoholicsolution, and the mixture was shaken and gently warmed for tenminutes.Water and dilute mineral acid were then added, and the oilmas extracted with ether, washed with sodium carbonate, dried, anddistilled, when methyl a-cyano-A1-cyclopenteneacetate passed over as acolourless oil, boiling a t 152'/17 mm. The ester gradually crystsl-lised, on keeping overnight, in colourless crystals, melting a t 3 5 O ; i tis soluble in most organic solvents, and is easily recrystnllised fromdilute methyl alcohol.(b) With Piperidine.-Equimolecular proportions of cyclopentanoneand methyl cyanoacetate were mixed with a few drops of piperidine,and the condensation was complete at the end of four hours. Theproduct was poured into water, extracted with ether, and treatedexactly as described under (a).The product was identical in everyrespect with that prepared by method (a) :0.1682 gave 11-8 C.C. N, (moist) at 14" and 740 mm. N = 803.C9H,,02N requires N = 8.5 per cent.?H2-CH>C* CMe (CN) C0,Me. CH,*CH2This ester is prepared by the action of methyl iodide and sodiummethoxide on ethyl a-cyano- A1-cyclopenteneacetate. Sodium (2 grams)was dissolved in methyl alcohol, and to the cooled solution the cyano-ester (15 grams) was added. The mixture at once assumed a deep redcolour, and methyl iodide (30 grams) was then added in small quantitiesat intervals, care being taken to avoid any increase of temperature.After keeping for an hour, and then warming for a short time on thewater-bath, the deep colour faded to yellow, and the liquid was poureACETIC ACXD AND 1-METHYL-A2-CY CLOHEXENE-3-ACETIC ACID.491into water, acidified, and extracted with ether, washed with sodiumcarbonate, dried, and evaporated. The methyl-substitution productdistils constantly a t 160"/20 mm. as a colourless oil, with an odourresembling its lower homologue; it showed no signs of crystallisingeven when placed in ice :0-1279 gave 0.3156 CO, and 0.0889 H20.C,,H,,O,N requires C = 67.0 ; H = 7.3 per cent.Hydq*oZysis.-The hydrolysis was effected by means of methyl-alcoholic potash, and the resulting cyano-acid was submitted todistillation under diminished pressure, when carbon dioxide waseliminated, and a nitrile, possessing an odour quite distinct from thatof the lower homologue (see below), passed over a t 123"/50 mm.Theanalysis gave numbers which were approximately correct fora-A1-cyclopentenepropionitrile.C = 67.3 ; H = 7.7.A1-cyclo Penteneacetonitde and A1-cycloPenleneacstic Acid,>C*GH,*CO,H. QH, CHCH,*CH,When a-cyano-Al-cyclopenteneacetic acid is distilled under 100 mm.pressure, it suffers decomposition with elimination of carbon dioxideand formation of Al-cyclopenteneacetonitrile. On refractionating thedistillate, it; was readily obtained pure as a colourless oil, possessing apungent odour characteristic of a nitrile, and distilling at 124*/100 mm.or 150°/200 mm. :0.1080 gave 12.4 C.C. N, a t 20" and 758 mm.C7H,N requires N = 13.1 per ctent.The hydrolysis of this nitrile was effected by digesting it for twenty-four hours with 20 per cent. alcoholic sulphuric acid, and, on cooling,ammonium sulphate separated in crystals. After dilution with water,the product was extracted with ether, the ethereal solution washedwith water until free from alcuhol, and then with dilute sodiumcarbonate ; the residue obtained after evaporation of the ether con-sists of a mixture of ethyl Al-cyclopenteneacetate with some unchangednitrile, and this was distilled under diminished pressure.The mixturewas now digested with methyl-alcoholic potash for half an hour, and,after the addition of water, the nitrile was removed by extraction withether. The alkaline solution was evaporated, and, when cool, acidifiedwith dilute hydrochloric acid. An oily acid was precipitated, whichsoon solidified, and, after remaining in contact with porous porcelain,it was purified by distillation under diminished pressure and analysedimmediately :N = 13.1.0.1220 gave 0.2968 CO, and 0.0859 H,O.C = 6 6 . 4 ; H=7%C7H,,0, requires C = 66.7 ; H = 7.9 per cent492 HARDING AND HAWORTH : SYNTHESIS OF' A~-CYCLOPENTENE-An analysis of the silver salt gave the following result :0.1140 gave 0.0660 Ag.C,H,O,Ag requires Ag = 46-3 per cent.A1-CycZoPenteneacetic acid crystallises in colourless prisms, melting,as found by Wallach, at 51-52', and distils as a viscid oil at 132O/16 mm. (Wallach : 122O/11 mm.). It is readily soluble in most organicsolvents. After exposure to the air, it gives numbers on analysiswhich are always low in carbon; this is due to oxidation at thedouble linking, which takes place with greater ease than in the caseof the six-carbon-ring homologue (Trans., 1908, 93, 1960), and fromthe point of view of comparative stability this observation is ofconsiderable interest.1 : 2-Dibromocyclopentene-1-acetic acid melts at 87-88" (compareWallach and Speransky, Annakn, 1902, 323, 159).1-Bromocyclopentaneacetic acid was obtained by stirring the solidunsaturated acid with aqueous hydrobromic acid saturated at Oo.The product was poured on porous porcelain, and afterwards re-crystallised from light petroleum, from which solvent it separates inthin, colourless plates, melting at 76' :Ag= 45.9.0.1770 gave 0.1625 AgBr.Br- 39.0.C7HI102Br requires Br = 38.7 per cent.flH,*CHCH,*CH2 cyclo Pentan- 1 -olacetic Acid, 2>C(OH) *CH;CO,H.Ethyl cyclopentan- 1-olacetate, prepared as described by Wallachand Speransky (Annalen, 1902, 323, 159), was obtained as a viscid,colourless oil, distilling at 1 28-130°/20 mm.(Wallach and Speranskygive 105-107'/11 mm.). This ester was bydrolysed with methyl-alcoholic potash, and the hydroxy-acid extracted from the acidifiedsolution by means of ether. On evaporation of the dried etherealsolution, the acid solidified, and was obtained pure by recrystallisationfrom a mixture of benzene and light petroleum, when it separated incolourless plates containing &H,O, and melted at 76'. This acid isvery soluble in benzene, ethyl acetate, chloroform, or alcohol, butsparingly so in light petroleum or water :0.1 176 gave 0.2370 CO, and 0-0920 H20.The silver salt was obtained in flat needles :0.1960 gave 0-0840 Ag.C = 54.9 ; H = 8.7.C7H120a,QH20 requires C = 54.9 ; H = S.5 per cent.Ag = 42.8.C7H,,0,~g requires Ag = 43.0 per centACETIC ACID AND 1-METHY L-A2-CY CLOHEBENE-3-ACETIC ACID.493Ethyl 1-Bromocyclo~elatnnsucetate,$fH2*CH 2>CBr CH,=CO,E t, CH,* CH,and Ethyl Al-cycloPenteneacetute.When ethyl cpclopentan-1-olacetate is gently warmed in contactwith a saturated solution of hydrobromic acid, the bromo-ester isformed, and if the product is left not longer than twenty minutes incontact with the aqueous solution, it escapes hydrolysis to the corre-sponding acid, The heavy oil which is formed on the addition ofwater is extracted with ether, washed with water and sodiumcarbonate, and then dried and distilled, when ethyl l-bromocyclo-pentaneacetate is obtained as a pleasant smelling, colourless oil, whichdistils at 142-143'/35 mm.Hydrobromic acid is readily eliminated from the above bromo-ester, and in the present case the process was carried out by digestingfor two hours with twice its volume of dimethylaniline.On addingwater and acidifying with dilute hydrochloric acid, the base wasrecovered at the end of the operation, and the resulting unsaturatedester extracted with ether and purified by distillation, when it wasobtained as a colourless oil distilling at 1 0lo/1 6 mm. This was analysedimmediately, with the following result :0.1375 gave 0.3550 CO, and 0.1111 H20.C,H,,O, requires C = 70.1 ; H = 9.1 per cent.This ester on hydrolysis gave the corresponding Al-cgclopentene-acetic acid, m.p. 31-52', which has already been described onp. 492.C = 70.4 ; H= 9.0.cycloPentylideneacetic Acid, c: H2* CH2>C:bK* U0,J.I.CH2*CH2In order to prepare this acid, cyclopentan-1-olacetic acid (6 grams)(see p. 492) was digested for two hours with acetic anhydride(8 grams), and at the end of this time the product was distilled ina current of steam and a large volume of distillate collected (Wallach,Annalen, 1909, 365, 255). The distillate was saturated withammonium sulphate and extracted with ether, the ethereal solutionwashed many times with water to remove acetic acid, and then driedand evaporated.The residue soon crystallised in long, slender needles,which melted a t 61'. The acid decolorises cold permanganate solutioninstantly, with the formation of cyclopentanone. The silver salt preparedin the usual way was analysed :0.2170 gave 0.1007 Ag. Ag= 46.4.C7H,0,Ag requires Ag = 46.3 per cent494 HARDING AND HAWORTH : SYNTHESIS OF A~-CYCLOPENTENE-a- Cyano- I -meth yl- A,-c yclohexene-3 -acetic Acid,and its Ethyl Estey.\V hen 1-methylcyclohexan-3-one is mixed in alcoholic solution withthe sodium derivative of ethyl cyanoacetate in equimolecular quantities,condensation takes place in a similar manner to that described in thecase of cyclopentnnone on p. 489 if the same conditions areobserved. The product was diluted, acidified, extracted with ether,and washed with water and dilute sodium carbonate (A).The residuefrom the ethereal solution yielded a little unchanged 1-methylcyclo-hexan-3-one on distillation under diminished pressure, also a smallquantity of 1-methyl-A2-cyclohexene-3-acetonitrile (see p. 495), andthen ethyl ~-cyano-l-methyl-A2-cycZohexene-3-acetate distilled over at168--169O/18 mm. as a colourless oil, possessing a faint butcharacteristic odour :0.1459 gave 0.3780 CO, and 0.1074 H20.0-1588 ,, 9-6 C.C. N, a t 9O and 744 mm. N= 7.1.This ester can also be obtained in a better yield by employing equi-molecular quantities of 1-methylcyclohexan-3-one and ethyl cyano-acetate and adding a few drops of piperidine. Under the influence ofthis reagent, the condensation is complete in about two hours, and themixture soon becomes turbid, owing to the separation of water.Towards the end of the operation the mixture was heated in a rapidlyboiling-water bath.The resulting yellow oil was diluted with water,extracted with ether, washed well with dilute hydrochloric acid, dried,and distilled.The cyano-acid is obtained in excellent yield from the sodiumcarbonate washings (A) in the first condensation. The alkalinesolution was acidified with dilute hydrochloric acid and extracted withether, and the ethereal solution dried and evaporated. The residueconsisted of a viscid, yellow oil, which was cooled in a freezing mixture,when it soon solidified. The solid was freed from adhering oil byplacing it in contact with porous porcelain, and afterwards recrystal-lised from benzene, from which it separates in short needles,melting sharply at 112' :C = 69.5 ; H = 8.2.C,,H170,N requires C = 69.6 ; H = 8.2 ; N = 6.7 per cent,The yield is about 60 per cent.0,1122 gave 0,2738 GO, and 0.0722 H,O.C = 66.9 ; H= 7.1.0-1558 ,, 10.9 C.C. N, at 21' and 760 mm. N=7*9.C,,H,,O,N requires C = 67-0 ; H = 7.2 ; N = 7.8 per cent.a-Cyano-l-methyl-A2-cyclohexene-3-acet~c acid is insoluble in cold,and slightly soluble in warm, water; it is also insoluble in lighACETIC ACID AND 1-METHYL-A2-CYCLOFiEXENE-3-ACETIC ACID. 495petroleum, but dissolves with considerable readiness in alcohol, benzene,or ethyl acetate. In contact with concentrated alkali in the cold it isdecomposed, with formation of 1-methylcyclohexan-3-one.It does notreact with hydrobromic acid to form an additive product.1 -Methyl- A2-cy clohexene-3-acetonitrile,This nitrile is prepared by the slow distillation of a-cyano-1-methyl-A2-cyclohexeneacetic acid under a pressure of 90 mm. The operationis accompanied by the elimination of carbon dioxide, and the nitrilepasses over as a light mobile liquid between 150' and 160'. It waspurified by redistillation, when it bojled constantly a t 152'/90 mm.(Wallach and Beschke, Annalen, 1906,347,341, give 108-1 12'/10 mm.and 230-234O under atmospheric pressure), and was obtained asa colourless oil, possessing a powerful nit,rile-like odour :0.1473 gave 0.4300 CO, and 0.1276 H,O.0-1141 ,, 10.4 C.C.N, at 20° and 758 mm. N= 10.4.C = 79.6 ; H = 9.6.C,H,,N requires C = 80.0 ; H = 9.6 ; N = 10.3 per cent.1-Methyl-A2-cyclohexene-3-acetic Acid,CH 2 CH2-CH, CH>C*CH,*CO,H.The hydrolysis of the above-mentioned nitrile was carried out underthe following conditions :The pure nitrile, boiling constantly at 152'/90 mm., and preparedfrom recrystallised cyano-acid, m. p. 112O, was digested for twelvehours with 10 per cent. alcoholic sulphuric acid. The mixture oncooling was poured into water, the precipitated oil extracted withether, and the ethereal solution dried and evaporated. The residueconsisted of ethyl l-methyl-h2-cycZohexene-3-acetate, along with someunchanged nitrile, and this mixture was distilled under 100 mm.pressure and then warmed for fifteen minutes with methyl-alcoholicpotash. The product was diluted with water, and the nitrile removedby extraction with ether.The aqueous solution was evaporatedgently, and then acidified, when the acid separated as an oil, whichwas dissolved in ether and afterwards distilled. It boiled at152-15So/20 mm., but was still further purified by solution in ether,extracting by means of sodium carbonate, and again recovering fromthe alkaline solution. It now distilled constantly at 149'114 mm., andwhen cooled in ice rapidly solidified to a mass of fern-shaped crystals.These were drained on an ice-cold porous tile, and the adhering oil wasabsorbed, leaving the acid as lustrous crystals, which melted about 25'496 HARDING AND HAWORTH : SYNTHESIS OF A'-CYCLOPENTENE-Both in odour and appearance this substance closely resembles1-methyl-A~-c~clohexene-4-acetic acid, m.p. 41", obtained by Marck-wald and Meth (see introduction), and A1-cyclohexeneacetic acid,m. p. 3 8 O :0.1520 gave 0.3879 CO, and 0.1270 H,O. C = 69.6 ; H = 9.2.Its basicity was determined by titrating with iV/lO-sodium0.2658 neutralised 0-0696 NaOH, whereas the same weight of'It is exceedingly probable that the above acid, m. p. 2 5 O , is identicalwith the oily acid previously obtained by Wallach and Salkind(AltanaZen, 1900, 314, 151 ; compare also Thtry, Bull SOC. chim., 1902,[iii], 27, 595, and Wallach and Beschke, Annalen, 1906, 347, 340).The amide of this acid was prepared by digesting 1-methyl-A2-cycZo-hexene-3-acetonitrile with alkali.It crystallises from ether inglistening, silvery plates, melting at 1509 Wallach and Beschke(Annulen, 1906, 347, 340) give the melting point of this amide asC,H,,O, requires C = 70.1 ; H = 9.1 per cent.hydroxide :a monobasic acid, C9Hl40,, requires 0.0690 NaOH.153-154':0.1395 gave 11.2 C.C. N, at 14' and 760 mm. N=9*4.C,H,,ON requires N= 9.1 per cent.Methylation of Ethyl a-Cyuno-1-methy~-A2-cyclohexene-3-acetute.Formation of Methyl a-C~c;c~~o-a-l-~~lethyl-h2-cyclof~exene-2-pro~~onote,CH,<CH,--CH; CHMe*cH>C*CMe( CN) C0,Me.Ethyl - u - cyano-l-methyl-Az-cycZohexene-3-acetate was mixed inmethyl-alcoholic solution with an equirnolecular quantity of sodiummethoxide, and an excess of methyl iodide was gradually added.Thereaction was vigorous, and required cooling at intervals ; it wascompleted by warming gently on the water-bath for fifteen minutes.The product was poured into water, extracted with ether, and distilled,when it passed over constantly at 140-142°j10 mm. :0.1299 gave 0.3298 CO, and 0.0945 H,O.0.1900 ,, 11.9 C.C. N, a t 18' and 760 mm. N=7.2.C = 69.3 ; €€ = S.1.C,,H,?O,N requires C = 69.6 ; H = 8 9 ; N = 6.7 per cent,a-1 -Methyl-A2-cycloliexene- 3 -propionitrile,and a-l-~~ethyZ-A2-cyclohesene-3-~ropiolzic Acid.The above cyano-ester was hydrolysed by boiling for ten minuteswith methyl-alcoholic potash, and, after the addition of water anACETIC ACID AND 1-METHYL-A2-CYCLOHEXENE-3-ACETIC ACID. 497evaporating, the alkaline solution was acidified and the oil whichseparated mas extracted with ether.The cyano-acid could not beobtained crystalline, and therefore the crude oil was distilled under90 mm. pressure, when carbon dioxide was eliminated and an excellentyield of nitrile was obtained. It was purified by redistillation,and was obtained as a colourless, mobile liquid, possessing apleasant sweet odour, and boiling a t 152-153"/90 mni.:0.1382 gave 10.4 C.C. N, at 17" and 757 mm.Hydrolysis.-The ni!rile was boiled for twenty-four hours with twiceits volume of alcohol, containing 20 per cent. of sulphuric acid. Itwas observed that the reaction proceeded very slowly, in strikingcontrast to the hydrolysis of the lower homologue, 1 -methylcycZo-hexene-3-acetonitrile (p.495). The product was diluted with water,extracted with ether, and the mixture of nitrile and ester distilledunder 100 mm. pressure. The distilled oil was now digested for tenminutes with methyl-alcoholic potash, and, after dilution with water,the nitrile was removed by extraction with ether ; on acidifying thealkaline solution the acid was obtained, and was distilled under 12 mm.pressure, when it passed over as a colourless oil, boiling at 144-148",and possessing the odour of a fatty acid :N = 9.6.CloH15N requires N = 9.4 per cent.0.1195 gave 0.3110 CO, and 0.0999 H20. C=71*1; H=9.3Cl,Hl,02 requires C = 71.4 ; H = 9.5 per cent.I t s basicity was controlled by titrating with N/lO-sodium hydroxide :0.2146 neutralised 0*0508 NaOH, whereas the same weight OF amonobasic acid, ClOHl6O2, requires 0.051 1 NaOH.The above acid is doubtless identical with that obtained by Wallachand Evans (Annaclen, 1908, 360, 51), who give the boiling point155-157"/17 mm.CH2<cH2*cH CH,*CH, >C.CHPh.CN.This substance was prepared as follows : Phenylacetonitrile (12grams) was mixed with a solution of sodium (2.3 grams) in ethylalcohol, and, after cooling, cyclohexanone (10 grams) was added.Theproduct was heated for fifteen minutes on the water-bath, and &hesolution became somewhat yellow in colour. It was then cooled,diluted with water, acidified, and the precipitated oil extracted withether. The ethereal solution was washed with water and dilute sodiumcarbonate, dried, and evaporated. On distillation of the residue, acolourless oil was obtained, which distilled at 176'/10 mm., andpossessed a pleasant ethereal odour 498 PRING: THE DIRECT UNION OF CARBON AND0.1160 gave 0.3618 CO, and 0.0825 H,O.A portion of the distillate, which was too small to investigate,crystallised after some time.The hydrolysis of this nitrile was attempted with alcoholicsulphuric acid, and also with alkalis, but the result in each case wasthe decomposition of the molecule with the formation of phenylaceticC = 85.1 ; H = '7.9.C,,H,,N requires C = 85.3 ; H = 7.6 per cent.acid and cyclohexanone.a Phanyl- I -methyl- AS-c yclohexene-4-a~tonitriZe,The preparation of this nitrile is analogous t o that which has beendescribed above. The oil on distillation passed over as a colourlessliquid at 191°/13 mm., and possessed a faint but pleasant odour ofnitrile :0.1133 gave 0.3533 CO, and 0,0849 H,O.0.1263 ,, 7.6 C.C. N, at 18' and 752 mm. N- 6.8.C = 85.0; H = 8.3.C,,H17N requires C = 85.3 ; H = 8.1 ; N = 6.6 per cent.We wish to extend our thanks to Prof. W. H. Perkin for theinterest he has manifested in the progress of this investigation.THE UNIVERSITY,M ANCHESTER

ISSN:0368-1645    

DOI:10.1039/CT9109700486

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

498 PRING: THE DIRECT UNION OF CARBON ANDLIV.-The Direct Union of Carbon and Hydrogenat High Temperatures. Part II.By JOHN NORMAN PRING.THE question of the direct union of carbon and hydrogen, whichformed the subject of a previous paper by the author in con-junction with R. s. Hutton (Trans., 1906, 89, 1591), has recentlyreceived a good deal of attention. In the paper just cited, thesynthesis of acetylene at relatively very low temperatures (from1850O upwards) was established, but the investigation of theformation of methane at lower temperatures gave less decisiveresults, and all that could be said was that the reactivity of thecarbon diminished with continued use, and that the presence ofimpurities increased the methane formation, probably by catalysisHYDROGEN AT HIGH TEMPERATURES.PART 11. 499As the temperature was raised in approaching the acetylene stage,and above this temperature, an increase in the methane wasobserved, which may be explained by the decomposition of theacetylene and the well-known greater stability of methane.The present work is intended, by still greater precaution in thepurification of the reacting substances, and by approaching theequilibrium stage from the opposite side, to clear up some of theoutstanding points of uncertainty, and particularly to ascertain theequilibrium values of methane in the system methane, hydrogen,and carbon over a large range of temperatures.Bone and Jerdan (Trans., 1897, 71, 41; 1901, 79, 1042) firstannounced the possibility of obtaining methane by the direct unionof carbon and hydrogen at 1200O.The percentage of methaneobtGined in these experiments varied frGm 0.7 to 1.4, mean 1.26.Berthelot (Ann. Chim. Phys., 1905, [viii], 6, 183) disputed theabove results, and emphatically expressed his belief that no hydro-carbons are produced at 1200-1350°, provided that the reactingmaterials are subjected t o an exhaustive purification.Mayer and Altmayer (Ber., 1907, 40, 2134) investigated themethane equilibrium in the system methane, hydrogen, and carbon.Hydrogen was allowed to react with carbon, to which nickel wasadded to serve as a catalyst. Experiments on the direct formationand on the decomposition of methane were made between thetemperatures 470° and 620O.In the thermodynamical equation :CH ET = - 18507 + 5,9934 TlOg2' + 0.002936 T2 + R T l o g ~ (ad2'as expressed by Haber, which gives the equilibrium ratio of methaneto hydrogen at all temperatures, the constant R was found byMayer and Altmayer to be 21-1.A t 1200" (1473O abs.) this givesthe value of 0.07 per cent. for methane.The experimental work is not, however, at all conclusive, asanalyses of the gases show amounts of nitrogen varying from2 to 20 per cent., and the percentages of carbon monoxide are notpublished.H. von Wartenberg (Zeitsch. anorg. Chem., 1909, 52, 299)investigated the cyanogen, hydrocyanic acid, and aoetylene equili-bria, but his experiments were carried out in a very rough manner,and he only extended the work to exceedingly low concentrations ofacetylene.In criticising the work of the present author andHutton, Wartenberg overlooks t.he fact of the decomposition ofacetylene into methane, and points out the anomaly of acetylenewhich is endothermic and methane which is exothermic bothincreasing in quantity a t the higher temperatures.VOL. XCVlI. L 500 PRING: THE DIRECT UXION OF CARBON ANDBone and Coward (Trans., 1908, 93, 1975) extended the earlierwork of Bone and Jerdan, and claimed finally to have provedthe direct union of carbon and hydrogen by the conversion of givenweights of carbon into a practically quantitative yield of methane.Although it seems probable that the conclusions of Bone and Jerdanand Bone and Coward, that carbon unites directly with hydrogen t oform methane, will be upheld, the fact that in their experimentsthe carbon was always in contact either with some known catalystor with porcelain, which, by reduction, might yield a catalyticallyactive compound, fully justifies the further investigation of thisreaction, which, moreover, is essential before concluding that directunion occurs.For these reasons it was thought desirable, in the course of thepresent investigation, t o adopt means to carry out the purificationof the carbon to the highest possible degree, and to use hydrogenin the purest and driest condition, so as to eliminate any possiblecomplication through the presence of carbon monoxide and nitrogen.It was also thought it would be of interest to investigate differentkinds of carbon in their behaviour towards hydrogen.Thevarieties studied were retort carbon, sugar-charcoal, and graphite.The method employed was similar to that used in the earlierwork (Pring and Hutton, Zoc. cit.), and consisted in the use of arod of carbon, or of a graphite tube provided with a narrow slitalong the top, and inside which could be placed the variety ofcarbon it was desired to study. These rods or tubes, which couldbe heated to any desired temperature by the passage of an electriccurrent, were suitably mounted at a considerable distance fromthe glass walls of the containing vessel, and all contact of theheated parts of the carbon with any substance but the surroundinghydrogen was avoided.The temperature of the carbon rods, in this manner, is sur-prisingly uniform, and can be readily estimated by means of aWanner optical pyrometer.A tubular glass flask, of 24 litres capacity, formed the reactionvessel, as shown in Fig.1. The tubes CC, of brass or copper, werestopped at PP with brass plugs by brazing. Graphite pieces DUwere inserted by mere contact in holes bored in the brass plugs,and the graphite supported the carbon rod or graphite tube K.A slow circulation of water through the metal tubes by means ofthe tubes ww during the heating of the rods sufficed to keep theformer quite cold. No visible heating of the graphite end pieceswas ever observed, whilst the temperature of the rod was uniformto within 2 or 3 mm. from these supports. The metal tubes werefitted gas-tight a t A and B by soft wax, which was occasionallHYDROGEN AT HIGH TEMPERATURES.PART 11. 501coated over with a solution of collodion in alcohol. These waxlutings allow the tubes a little play during the expansion of therod by heat and remain perfectly gas-tight under these conditions,even when the flask is completely evacuated. The leak of air intothe vessel seldom corresponded with more than 1 mm. when theflask was kept for one day under 1 cm. pressure. A charcoaltube was fitted at T, which could be cooled by liquidair, and thus complete the exhaustion of the vessel. Beforeeach series of experiments, this exhaustion was allowed toproceed for a few hours, and the rod kept a t a temperatureof about 1500O in order to dry the inside walls of the vesselas completely as possible and remove any occluded gas or finalimpurity from the carbon.The outlet tube f1 was to enable aE'JG. 1.b uYpreliminary partial exhaustion of the apparatus by a water pump,and the outlet F led to a mercury gauge and to a Topler mercurypump, where a more complete exhaustion could be effected orsamples of gas withdrawn from the vessel for analysis. Thehydrogen used in these experiments was generated by the electro-lysis of baryta solution. The baryta was for this purposerecrystallised several times, and the electrolysis conducted in a largeU-tube placed in a hot-water bath, a current of about 3 amperesbeing used. The hydrogen was then passed through a heated Jenacombustion tube filled with copper gauze, a small heated tube filledwith platinised asbestos, and then through a calcium chloride tube.Two methods were then at different times used far further purifica-tion of the gas.A.After leaving the calcium chloride tube, the hydrogen wasL L 502 PRING: THE DIRECT UNION OF CARBON ANDpassed through a spiral glass tube, cooled on the outside by liquida,ir. The air ,in the drying tubes was first displaced by passinga current of hydrogen through for several hours, and allowing toescape through a side-tube, which dipped under mercury. Thehydrogen was then admitted through the tap M , which could becarefully regulated, into the vacuous globe.B. The gas was filtered through a specially constructed palladiumtube, making use of the well-known permeability of this metal tohydrogen when slightly heated.The tube was of the form shown in Fig.2 at X, the total lengthbeing 30.5 cm., external diameter of wide part 5 mm., and ofnarrow part 2 mm., thickness of walls 0.5 mm., weight 14.2 grams.The tube was connected to the glass a t A by means of rubbervalve tubing, which was then covered with pressure tubing.The palladium was encased in a Jena glass tube, actual contactwith the glass being avoided by a palladium bridge at B. ThePIG. 2.I 1glass tube was surrounded by an electrical wire resistance furnaceR, whereby a temperature of 350-400° could be conveniently main-tained. The outlet tube S was sealed on to the tube V (Fig. 1).By opening the tap M (Fig. l ) , the palladium tube could beevacuated together with the flask, and, on warming, perfectly purehydrogen diffused through and gradually filled the vessel.Therate of diffusion varied, of course, with the pressure inside theflask. With the palladium tube at 400°, when the vessel qasvacuous, about 20 c.c., and with a pressure of 60 cm. about 5 c.c.,entered per minute. It was never necessary to fill the vesselentirely, as the subsequent heating of the rod expanded the gasto atmosphere pressure.Temperature Readings.It was found by comparison with a thermo-element (H. C. Green-wood, Trans., 1908, 93, 1486; Proc. Roy. Soc., 1909, 82, A , 402)that the particular pyrometer used is accurate within 20° at1250O when sighted on to the outside of the carbon rod, and that aHYDROGEN AT HIGH TEMPERATURES.PART 11. 5031550°, 1670°, and 2000O there is not a departure of more than 15Ofor (‘ black body ” radiation. Consequently, the only error of anymagnitude which could arise at these temperatures would be dueto departure from (‘ black body ” radiation, and this deviation inthe case of carbon is known to be small. I n the experimentsdescribed below, the pyrometer was calibrated against a thermo-element a t 1200°, and then frequently checked by means of anamyl acetate lamp.Analysis of Gas.The estimation of the small quantities of methane in the previouswork (Pring and Hutton, Zoc. cit.), which was effected in a Sodeauapparatus, without a preliminary condensation of the hydrogen,was a matter of some difficulty on account of the tendency toform oxides of nitrogen on exploding the gas with excess ofoxygen.The presence of acetylene was ascertained qualitatively by theformation of cuprous acetylide, but in the quantitative estimation,by the use of bromine or fuming sulphuric acid, no means wereadopted to distinguish between the acetylene and ethylene or anyother unsaturated hydrocarbon.I n the work now described, a condensation of the hydrogen wasusually first made by means of palladium foil in cases where nounsaturated hydrocarbons were present.I n this way, 1000 to1500 C.C. of the resulting gases were condensed to 50-100 c.c., andthus an accuracy of from ten to thirty-fold in the methaneestimation was obtained. Samples of gas which contained un-saturated hydrocarbons, in addition to methane, were notcondensed by palladium, but were analysed as follows: Thegas was first treated with a solution of ammoniacal silverchloride to remove acetylene.Two separate lots of this reagentwere used, the last being freshly prepared, to ensure completeremoval of this gas. A treatment with bromine or fuming sulphuricacid, followed by potassium hydroxide solution, was then carriedout, t o remove ethylene. The carbon monoxide was then removedby two treatments with ammoniacal cuprous chloride solution, andthe methane estimated by exploding with an excess of oxygen andmeasuring the carbon dioxide.Purification of Carbon.The method employed by Bone and Jerdan and Bone and Coward(Zoc. cit.) for purifying the carbon consisted in igniting the finelydivided substance for several days in a stream of chlorine, followedby hydrogen, at a temperature of 1100-1200°.The disadvantag504 PRING: THE DIRECT UNION OF CARBON ANDof this method lies in the improbability of evei- being able to removethe last traces of combined hydrogen, and the serious contaminationwhich must result from contact with the containing vessel duringthe long period necessary for the treatment.The methods adopted in the present investigation were as follows.A. I n the cases where amorphous carbon rods, usually of 0.4 cm.diameter and 10 mi. long (retort carbon), were used, these wereplaced in a carbon tube furnace and treated for two to three hourswith a current of chlorine at about 1500°, and then for aboutfifteen minutes with a current of nitrogen, and finally for two tothree hours with a current of hydrogen.The carbon tube used forthis furnace was 28 cm. long and 2 cm. external diameter. Elec-trical connexions were made at the end by graphite rectangularbars, and a current of 160 amperes at 11 volts was found toproduce a temperature of about 1550O when charcoal was usedas packing around the tube.An analysis made of a rod after this purification showed thepresence of less than 0.10 per cent.. of hydrogen and 0.05 per cent.of ash. After this treatment, the rod was mounted in the glassreaction vessel, being supported by the graphite end-pieces. It washere raised to a temperature of about 1500O by the passage of anelectric current while the vessel was kept at a high vacuum bymeans of charcoal cooled by liquid air.I n some experiments ameasurement was made, by means of a McLeod gauge, of thepressure inside the vessel under these conditions, and was foundto vary from 0.01 to 0.10 mm. It was found possible to maintainthis low pressure for an indefinite period. The carbon rod, whichwas heated for an interval of from one to five hours, received inthis way a further purification, while an effective drying of theinside of the vessel was a t the same time ensured.In addition to the above treatment, great importance is attachedto the fact that the same rod was used continuously throughouta large number of experiments, after each of which the heatingin vacuum was again repeated for a short time, and only the purehydrogen was allowed to enter the vessel after each evacuation.B.In the case of experiments with sugar-charcoal, the procedureconsisted in gradually igniting sugar to a bright red heat, reducingthe carbon to a fine powder, placing in a graphite boat, andtreating this in the carbon tube furnace alternately with chlorine,nitrogen, and hydrogen, as described above for the rods. A tubewas prepa'red from Acheson graphite, 9.5 cm. long, 0.95 cm. external,and 0.6 cm. internal diameter, and provided with a narrowlongitudinal slit. This was subjected to a prolonged purificationtreatment, and then filled with the purified charcoal and mounteHYDROGEN AT HIGH TEMPERATURES. PART II.505in the glass vessel in the manner employed with the rods. In oneseries of experiments the carbon used was purified with even morerigour, by repeating the alternate treatment with chlorine,nitrogen, and hydrogen, at. 1550O for six times over a total periodof six hours.A disadvantage found with these tubes is that, unlike the case ofthe thinner carbon rods, the temperature is only uniform over acentral region of about two-thirds of the tube, and from here itgradually falls off to the cooled supports. A t higher temperatures,however, this uniform zone extends over a somewhat greater length.Another inconvenience with this method is that while the tem-perature of the tube is Geing raised, the finely divided carbonshows a curious tendency to disperse and be expelled from theaperture, even when this is very small.This scattering is muchmore marked when the heating is done in a vacuum, and in allcases necessitates a very gradual raising of the temperature.C. For examining the reaction with graphite, the tube employedin the above experiments was used empty, having been purified byprolonged treatment with chlorine and hydrogen.The procedure in an experiment was as follows. After thepreliminary heating of the purified carbon in the evacuated reactionvessel, pure hydrogen wils admitted through the tap M (Fig. 1).The pressure of hydrogen could be measured by means of themercury gauge connected to F, which also led to the pump L.The mercury gauge also served as an outlet for the gas during itsexpansion through the heating of the carbon.During the experi-ment the current employed was kept constant, and temperaturereadings were taken at frequent intervals by the Wanner opticalpyrometer. A t the end of each experiment the gas was removedby a Topler pump and transferred to a graduated gas holder con-taining glycerol and water, and after measurement was condensedby palladium foil. Sixty grams of this foil, cut into small strips,were, for this purpose, placed in a 300 C.C. flask provided with awide ground-glass stopper and a, sidetube wit4 a ground joint andmercury seal. The flask was exhausted by a Topler pump, and thegas from the holder then allowed to enter. The flask was heatedby a water-bath to 80-100°, when absorption of the hydrogenwas very rapid if the amount of carbon monoxide present wasbelow 0.01 per cent.The residual gas was removed by the pump,measured over mercury, and analysed.Tabulated List of Results.Values for the methane, given to two places of decimals, denotethat the analysis has been made on the uncondensed gas, whils506 PRING: THE DIRECT UNION OF CARBON ANDthe methane in the gas condensed by palladium has been estimatedto three places. The same carbon was used throughout each serieswithout, in any way, dismantling the apparatus.Part l.--Reaction.s Examined in Presence of Carbon Monoxide.A. Sugar-charcoal in graphite tubs.Series 1.-Sample purified by heating once in chlorine, nitrogen,and hydrogen alternately for one hour at 1550°, and then for halfan hour in a vacuum, a t 1200°, in the reaction vessel:Order Product (percentage).Time of ex- I \periment.Temperature. in hours. co . CH,. NP1 1200-1250" 2 0.70 0-29 0.150.6G 0,247 -A2 1345 lit-Series 2.-Sample of sugar-charcoal purified by heating alter-nately in chlorine, nitrogen, and hydrogen six times for six hoursat 1550°, and then in a vacuum for half an hour before eachexperiment:Orderof ex-periment.123456-TimeTemperature. in hours.1250 I*1250 41500 141250"1250 21250-1300 13 -Product (percentage).A r \ co. CH4. N,.0.87 0.400 -_0-6 0.4 0-30.35 0.279 -0'36 0'198 -0-87 0 '24 0'200.97 0-324 -0.70 0.18 -The above series clearly shows the diminution in the amount ofmethane formed after the first few times of use.Series 3.-Sample of sugar-charcoal purified by heating five timesalternately in chlorine, nitrogen, and hydrogen for five hours, andthen in a vacuum as above:Product (percentage).Order of Time - 0'8 0'1061.8 0.143 2 161 5 13 1250 2 0.65 0-196experiment. Temperature.in hours. co. CH,.1 1230-1270" 19The above series was conducted with the view of ascertaining ifthe heating of the carbon t o about 1600° wouid cause any markeddiminution in the reactivityHYDROGEN AT HIGH TEMPERATURES, PART 11. 507B. Experiments with graphite :Order ofexperiment.1657345Temperature.1250"125012501250132515201720Timein hours.Product (percentage).ICO.0.150'010.130.250'181'32 '0>CH,.0'1430'0460.2320.2520.1700.1720'246Part 2.-Reactions Conducted with Very Low Concentrations o,fCarbon Monoxide.Series 1.-Retort carbon.Amorphous carbon rod purified by heating alternately inchlorine, nitrogen, and hydrogen for two hours at 1550°, and thenin the reaction vessel in a vacuum at 1425O for two hours:Order Product (percentage).of ex- / \periment.Temperature. Time. CO. CH,. C,H,. C,H,.h4 11 00" 34 hours 0'006 0.123 - -6 1100 13 ,, 0'012 {~~~~~ - -- - 1 1150 24 ,, 0-3 0.2387 1200 50 mins. <0*01 0.150 - -5 1200 5 hours 0.01 0.165 - -18 1200 11 ,, <0'005 0'334 - -0'15 0-160 - - 2 1300 1% $ 9 3 1300 4 ,) 0-01 0'220 - -0-010 0.178 - - 8 1400 2 9 9 9 1500 2 ,, 0'04 0.168 -11 1600 35 mins.0.001 0.210 - c10 1600 12 hours 0.02 0'240 - -12 1725 1 hour ~ 0 . 0 0 2 0.354 - -14 1770 15 mins. 0'32 0-40215 1830 12 0.15 0'530 nil -17 1950 30 mins. 0'44 0.86 0-20 0.2219 2055" 10 9 , 0 '33 1'13 1'30 0.97* Rod broke and arced for about three seconds a t end.- - 13 1200 22 ), 0'01 0-342-- -16 1850 1 hdhr 0.05 0.597 trace -Series 2.-Amorphous carbon rod, heated as last one.1 1570" 1 hour 0'160 0-154 nil nil2 1620 80 niins. 0'087 0.1813 2080 15 2 , 0 '35 1.08 0*;5 0 '454* 2180 11 9 9 0'10 2.18 1-80 1-72* Rod arced for about three seconds at en508 PRING: THE DIRECT UNION OF CARBON ANDPart 3.--Decomposition of Acetylene and Methane in Presence ofan Excess of Hydrogen at R g h Temperatures.Experiments on the decomposition of these hydrocarbons wereundertaken to attempt to decide to what extent methane mightarise at the higher temperatures as a secondary action from thedecomposition of acetylene, to measure its stability at these tem-peratures, and, if possible, t o find the final equilibrium value ofmethane from the other side.Acetylene was for this purpose prepared by dropping ethylenedibromide into hot alcoholic potash, washing the gas with alcohol,and collecting over water.About 5 litres of this were condensed by liquid air and thenallowed to evaporate, the middle portion being passed into a holderof about 200 C.C.over mercury. From here it could be admittedinto the reaction vessel through the tap A', the connecting tubehaving first been evacuated, together with tlie vessel.Methane wasprepared by decomposing commercial aluminium carbide withdilute hydrochloric acid, washing the gas well with ammoniacalcuprous chloride to remove acetylene and hydrogen sulphide, andthen liquefying the methane, vaporising, and collecting the middlefraction.Small percentages of acetylene or methane could in this waybe admitted into the reaction vessel, which was then filled withhydrogen. An amorphous carbon rod was used. Samples of gaswere withdrawn from the reaction vessel before and after eachexperiment. In some cases condensation with palladium wasresorted to. The results are tabulated below:EX-pcriment. Temperature.1 1480"2 1200°3 1775"4 1200"5 1580"6 1200"to 1620"Time.01 hour2 hours48 ) Y0I& hours;4 ) YJ )010 mins.1 hour025 hours02 hours02 hoursComposition of gas.CO.CH,, C,H,. C,H,. - - 0.6 -0-15 0'32 nil trace0'2 0'26 Y ) Y Y0.25 0.25 9 ) Y Y- - 3.50 -0.27 4'20 0.50 0-850'41 1 '41 nil 0'350'48 1 .oo > ) 0.55- - 20.2 -0'08 5.93 5-02 1'130.09 0.77 nil nil- 6 '000-073 4'63 --- 5.00.05 1 *75- 6-730'25 5-47Afl -.- --- - - --- -- HYDROGEN AT HIGH TEMPERATURES. PART 11. 509Experiment in which 5 per cent. of carbon monoxide was added,to study its effect on the decomposition of methane:- - 1200" 0 5 *O 6 -5- - 73 hours 4'2 5 '92__ - 64 3.72 5 *95Part IV.-AmrpJLous Carbon Rod with a Deposit of Platinum orbSurface to Assist the Reaction Catalytically.This rod was purified in chlorine, nitrogen, and hydrogen at thesame time as the previous ones, and was coated with a thin depositof platinum by electro-deposition, and then heated in the reactionvessel in a vacuum a t 1300O for half an hour.Pure hydrogen wasthen admitted, and the experiment conducted it9 usual. In theexperiments in column B a small percentage of methane wasadmitted to find the equilibrium from the decomposition.A.Product (percentage).Order of - experiment. Temperature. Time. GO. CH,.1 about 1050" 1& hours 0.052 0.8662 ) ) 1100 ;4 9 ) 0.007 0.6908 1200 7 7 0.011 0.5403 about 1300 30 mins. 0.014 0.3406 1500 45 > ) nil 0.297B.Decomposition of methane with same rod.1175- 1200" 0 - 2 '314 hours 0.006 1-141200 0 - 1 '951500 0 - 3 '20.003 0.594'2 7 ) 1 -03 0 *33012 9 aConclusions.The experiments described above clearly show that pure carboncombines directly with pure hydrogen at all temperatures above1100O.At 1200O the velocity of the reaction is so slow in theabsence of any catalyst that the estimation of the exact equilibriumvalue of methane is somewhat uncertain. An experiment extend-ing over twenty-two hours at 1200O seemed, however, to yield thelimiting value of 0-35 per cent. of methane, although this could notbe confirmed by approaching the equilibrium from the other side,as the decomposition of small amounts of methane by pure carbonat 1200O proceeds even more slowly than the synthetic reaction510 PRING: THE DIRECT UNION OF CARBON AND HYDROGEN.A t 1500O an equilibrium value of 0.17 per cent.of methaneappeared to be approached within about two hours, althougheven at this temperature the decomposition of methane was tooslow to serve for the evaluation of the equilibrium quantity.More definite equilibrium values were obtained by using carbonwhich contained a surface deposit of platinum. In this case, inexperiments at temperatures between 1050O and 1500°, the reactionwas very much accelerated, and the same percentage of methanewas finally obtained whether its formation or its decomposition wasSynthesis of hydrocarbons from pwc amosphous Methane equilibrium withcarbon. illaxiinwn amounts obtained. platinum coated carbon.x Sfyntlu&s of methane.o Decomposition of methane.investigated. The amount formed was 0.55 per cent.at 1200°,and 0-30 per cent. at 1500O.Above 1550O the percentage of methane began to rise with thetemperature. These increased quantities of methane do not, atthese temperatures, necessarily represent equilibrium values, butprobably arise from the decomposition of acetylene, although theamount of the latter gas present was too small to be detected below1850O.Experiments on the decomposition of hydrocarbons showed thatacetylene changes quickly to methane and ethylene above 1500°,and that the methane formed is comparatively stable. Thisbehaviour is similar to the decomposition which hydrocarbonCOLOUR AND CONSTLTUTION OF AZO-COMPOUNDS. PART V. 511undergo at lower temperatures (Bone and Coward, Trans., 1908, 93,1197).In the decomposition of acetylene a t 1 200-1400°, ethylene wasalso formed, and found to persist; consequently, this appears topreclude the possibility of the methane arising secondarily in theexperiments at these temperatures, as, in these cases, no trace ofethylene was found in the gas.Graphite and sugar-charcoal showed a similar behaviour toamorphous retort carbon in its reactivity with hydrogen.The presence of carbon monoxide seems to have no effect onthe final equilibrium in the synthesis or decomposition of methanea t any temperature employed, or on the velocity of the reaction.The synthesis of acetylene could not be taken to the equilibriumstage, as with methane, in the form of apparatus used. Acetylene,being endothermic, is stable in larger amounts the higher thetemperature, and would consequently undergo some decompositionin passing away from the heated carbon through the intermediatezones of temperature of the outside layers of gas.The equilibrium values obtained in the above work probablyrefer to systems of different concentrations than the surroundinggases, on account of a probable condensation of gas on the surfaceof the carbon or catalyst. This problem is now being investigatedby the use of high gaseous pressures and the examination of theeffect of catalysts other than platinum.In conclusion, I wish t o express my indebtedness to ProfessorE. Rutherford for the facilities he has extended for conductingthis research, and to Dr. R. S. Hutton for suggesting the work,and for his continued interest and assistance during its progress.ELECTRO-CHEMICAL LABORATORY,THE UNIVERSITY,M ANCHE~TEH

ISSN:0368-1645    

DOI:10.1039/CT9109700498

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

COLOUR AND CONSTLTUTION OF AZO-COMPOUNDS. PART V. 511LV.-The Coloui- and Constitution of Azo-compounds.Part V.By JOHN THEODORE HEWITT and FERDINAND BERNARD THOLE.DURING the progress of some work on the relationships existingbetween the constitution and selective absorption of certain polyazo-compounds, the authors of the present communication were muchstruck with the great colour change which takes place on diazotisin512 HEWITT AND THOLE: THE COLOUR ANDaminoazobenzene in hydrochloric acid solution. As is well known,azobenzene and aminoazobenzene both dissolve in alcohol, with ashade which is yellow in dilute solution, the head of the band ofslowest oscillation, but little persistence, lying a t about 2200oscillation frequency in the case of azobenzene (Hnrtley, Trans.,1887, 51, 152; Baly and Tuck, Trans., 1906, $9, 985; Hantzsch,Ber., 1909, 42, 2132), and apparently at about the same point withthe amino-derivative (compare Landauer, Ber., 1881, 14, 391, andC, Graebe, Zeitsch.plqsikul. Chem., 1892, 10, 689). The bestmarked and most persistent band given by alcoholic solutions ofazobenzene has its head at an oscillation frequency of about 3200.Similar observations have been made in the case of dimethyl-aminoazobenzene (2430, Hantzsch, Zoc. cit., p. 2133), p-a.mino-benzeneazophenol (2600), and pdimethylaminobenzeneazophenol(2400, Hewitat and Thomas, Trans., 1909, 95, 1297).I n all cases, however, where an amino-group occupies a para-position with respect to the azo-group, the formation of a monacidsalt by the addition of dilute hydrochloric acid in sufficient quantityconditions a change in colour to red, the oscillation frequencies ofthe heads of the persistent band of longest wave-length lying atabout the same point for the compounds enumerated; this is shownin the following table :p-Aminoazobenzene ........................2000 (see Fig. 1)p-Dimethylaminoazobenzene ........... 1900 (Han tzsch)p-Aminobenzeneazophenol ............... 1800 (Hewitt and Thomas)pDimethylaminobenzeneazopheno1 . , . 1800 ,, , , , ,This change, which corresponds with that observed on acidifyinga solution of methyl-orange, is now generally explained by supposingthe hydrochlorides to be derived from the equivalent quinonoidfGrm :C,H,*N :No C6H,*N H - C6H, *N H*N: c,H,: N H,CI.The possibility of a certain small amount of amino-aromatic saltbeing also present in solutions is not completely negatived, since onemay adduce in support of such a proposition the fact that Hantzschhas in some cases isolated yellow salts of aminoazo-compounds, andhas also obtained a tribromo-derivative of aminoazobenzene bythe direct action of the halogen in glacial acetic acid solution (Ber.,1908, 41, 1171, 1187, 2435); whilst, further, there is the well-knownaptitude for diazotisation of the aminoaza-compounds. In the lastcase one is inclined to formulate the reaction as taking placeaccording t o the scheme:C6H5-N:N*C6H,*NH3C1 + HO*N:O =2H,O + C6H,*N:N*C,H4*N( iN)ClCONSTITUTION OF AZO-COMPOUNDS.PART V.513although reaction in the sense :C6H5*NH*N:C,H4:NH2C1 + HO*NO =H,O + C,H5*NH*N:C6H4:N(:NOH)C1=2H,O + C,~,*N:N*C,H,*~(~~)C~does not seem so improbable when one considers the easy way inwhich the quinonoid hydrates of azophencls lose water, passingdirectly into the hydroxyazo-form :R*NHDN:C6H4:(OH), -+ R*N:N*C6H4*OH + H20.It is certainly highly improbable that the diazonium chloridespossess a similar structure to the salts of the parent aminoazo-FIG. 1.Oscillation frequencies.1600 18 2000 22 24 26 28 3000 32 34 36 38 4000 42 44 46 4800Benzeneazobenzenediazonium chloride.......................... Benzeneazophenyltrimethylammonium iodide.Aminoaxobenzene hydrochloride.compounds, for on adding nitrite to the bluish-red solutions of thelatter, the d o u r changes to an orange, which to the unassisted eyeappears rather more red in'shade than that of the free aminoazo-compounds or of azobenzene itself. In these circumstances itappeared very desirable to examine the absorption spectra, andfor this purpose we have compared benzeneazobenzenediazoniumchloride with the hydrochloride of aminoazobenzene on the onehand, and with benzeneazophenyltrimethylammonium iodide on theother.Comparison with other para-derivatives of azobenzene is alsopossible, and, as will be seen from the curve given in Fig. 1, benzene514 HEWITT AND THOLE: THE COLOUR ANDazobenzenediazonium chloride gives a curve which resembles some-what closely that given by benzeneazophenol (Tuck, Trans., 1907,91, 450).The head of the absorption band for benzeneazophenollies at an oscillation frequency of about 3000, whilst for thediazonium salt examined it is about 2950. Further, both of thesesubstances show an extension of the band towards the red end ofthe spectrum; a similar extension has also been observed withcertain aminoazophenols by Hewitt and Thomas (Zoc. cit.).On the same diagram will be found the curves for the absorptionspectra furnished by the hydrochloride of aminoazobenzene and bybenzeneazophenyltrimethylammonium iodide. The first of thesesubstances is almost without doubt of quinonoid structure, and itsabsorption, which closely resembles that of the hydrochlorides ofdimethylarriinoazobenzene and its hydroxy- and methoxy-derivatives,is absolutely different from that of the other two compounds, whichdo not, however, agree as closely between themselves as might havebeen expected for substances possessing similar structures. Ittherefore remains an open question whether the constitution of thediazonium salt is to be expressed by the formula:C,H,*N:N=C,H,*N( iN)CI,although it might.be urged that the difference in the groups*N( iN)Cl and -N( CH,),Clmight account for the comparatively minor differences in theabsorption spectra.Comparison of the absorption spectra of phenol (Baly andEwbank, Trans., 1905, 87, 1351) and benzenediazonium salts wouldhave been interesting, but since, according to Dobbie and Tinkler(Trans., 1905, 87, 273), the latter give absorption spectra similarto those of dilute solutions of the unstable diazotates, a referenceto the curve given in the latter case by these authors shows thatvery little aid can be expected.For the purposes of this work, aminoazobenzene was acetylated,the acetyl derivative recrystallised until of constant melting point,and hydrolysed.In examining its acid-alcoholic solution, hydro-chloric acid was added in such amount as not to produce anyfurther deepening of the red shade.The benzeneazophenyltrimethylammonium iodide was preparedby heating benzeneazodimethylaniline with methyl alcohol andmethyl iodide t o looo after keeping the mixture for eighteen hoursin the cold, and reaction was already practically complete. Theproduct was finally recrystallised from a large quantity of boilingwater.Benzeneazobenzenediazonium ChLloride.-The isolation of the soliddiazonium salt was effected by suspending 4.7 grams of aminoazoCONSTITUTION OF AZO-COMPOUNDS.PART V. 515benzene hydrochloride in 150 C.C. of alcohol (96 per cent.), andadding 2.4 grams of amyl nitrite diluted with 10 C.C. alcohol. Afterfifteen minutes’ stirring, any small solid residue was removed byfiltration and the diazonium chloride precipitated by ether, collected,washed with ether, and dried over sulphuric acid. The salmon-coloured powder obtained in this way proved, under the microscope,to consist of a mass of small but well-defined prisms:0.5506 gave 0.3211 AgCl. Cl=14*4.The salt dissolves in alcohol and water, showing considerablestability even in alcoholic solution.The absorption spectra wereobserved with freshly prepared alcoholic solutions, but even afterkeeping overnight a t the ordinary temperature a large amount ofthe diazonium salt was found to be still undecomposed. Onheating, the salt decomposes comparatively gently ; no detonationhas been observed, whilst the dry salt may be kept for monthswithout appreciable decomposition, still dissolving in water andcoupling with the usual azo-components. An aqueous solutionreacts, however, immediately with potassium iodide, giving p-iodo-azobenzene.PZatinichZoride.-This salt was prepared by precipitating anaqueous solution of the chloride with excess of chloroplatinic acid ;after washing and drying it formed a salmon-coloured powder.This salt also shows considerable stability, and decomposes in agentle manner when heated:C,,H,N,Cl requires Cl= 14.5 per cent.0.3228 gave 0.0768 Pt..Pt=23*8.(C12H9N4)2PtC16 requires Pt = 23.6 per cent.No ferrichloride has been obtained, but solutions of the chlorideyield a yellow precipitate with potassium dichromate. The salt,presumably b enzeneazob enzenediazonium dichromute, was washedand dried, but on account of the character of the detonation whichoccurred on heating, an analysis was not carried out.. Meldola(Trans., 1905, 87, 4) has also prepared this salt, but did not analyseit owing to its explosive properties.The absorption spectra are not such that the authors feel justifiedin drawing any rigid conclusion as to the constitution of thebenzeneazobenzenediazonium chloride ; i t is, however, a veryremarkable fact that the most stable diazonium salts are alwaysthose possessing a para-substituent, especially when the latterhappens to be an unsaturated and negative group.Reference maybe made to the cases of pnitrobenzenediazonium chloride, theacetylaminobenzenediazonium chloride described by Meldola (Proc.,1899, 15, 196; Trans., 1905, 87, l), and to the benzenesulphonyl-VOL. XCVII. M 516 HEWIT" AND THOLE: THE COLOUR ANDaminoaryldiazonium salts of Morgan and his co-workers (Trans.,1905, 87, 73, 921, 1302; 1906, 89, 4 ; 1907, 91, 1311, 1505, 1512;1908, 93, 602).Morgan and Alcock (Trans., 1909, 95, 1319) adopt a modificationof Cain's formula (Trans., 1907, 91, 1040) for the constitution ofdiazonium salts, but apparently do not attribute the stabilityconferred by negative para-substituents to any essential difference inconstitution.I f one follows Cain in ascribing to diazonium salts ahemiquinonoid structure, the possibility certainly arises that saltsof the negatively substituted type may be fully quinonoid instructure, and their greater stabi1it.y be thus accounted for :Benzenediazonium chloride (Cain) : H\/='-NCI. /\=/-g/-\p-Nitrobenzenediazonium chloride : 0: N=-/ k N C I .I \=/ II I 0Acylaminobenzenediazonium chloride : Alk*C(OH)*N=/=N\= I/=\Benzeneazobenzenediazonium chloride : c' H *N*N=(=/\=NCI.5~ AThus, whilst Cain represents the simple diazo-salts as analoguesof the labile " chinols," the above representation of the negativelysubstituted compounds resembles the constitution attributed to thefar more stable quinones.Iodoazob enzene.-In connexion with the work described in thispaper, iodoazobenzene was examined with a view to seeing if itwas capable of iodonium salt formation.As amino- and hydroxy-azobenzene readily yield quinonoid salts, so it is not impossible thatthe iodo-derivative may give corresponding salts containing tervalentiodine :Since, however, azobenzene itself gives unstable salts with acids,it might be argued that any salts yielded by iodoazobenzene shouldbe referred to the same type. It happens that azobenzene gives adifferent absorption in acid solution from that given by the mono-hydrochlorides of its amino- and hydroxy-derivatives ; the absorptionspectra of the two latter salts being comparable, although the headof the band of slowest frequency lies always more towards the redend of the spectrum in the case of the nitrogen compound.When iodoazobenzene is dissolved in benzene and hydrogeCONSTITUlLON OF AZO-COMPOUNDS.PART V. 517chloride led in, the colour darkens considerably, and separation ofa certain amount of solid occurs. This method of preparing thesalt, which gives such good results for hydroxyazo-compounds, isnot very suitable for preparing salts of iodine derivatives, as theseparation of solid matter is but slight. Nevertheless, a comparisonof the absorption spectra of iodoazobenzene in alcohol alone and inalcoholic solution of hydrogen chloride (see Fig. 2) renders it quiteprobable that combinat ion with h j drogen chloride occurs with formationFIG. 2.Oscillation frcqzmacies.1600 18 2000 22 24 26 28 3000 32 34 36 38 4000 42 44 46 48001 1Iodonzobenzene in alcohol.lodoambenzene in alcoholic hydrogen chloride.of an iodonium salt. I n fact, when iodoazobenzene is moistened w i t hbenzene and exposed to gaseous hydrogen chloride, two moleculesof the latter are absorbed, and a beautiful, nearly black, crystallinehydrochloride is produced.The authors acknowledge with thanks the aid afforded them bythe Government Grant Committee of the Royal Society, by whichthe expenses of this research have been defrayed.EAAT LONDON COLLEGE

ISSN:0368-1645    

DOI:10.1039/CT9109700511

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

518 CROSSLEY AND GlLLTNG: : ACTlON OF ETHYL CYANOACETATELV1.-Action of Eth,yZ Cyanoacetate on 5-chlo~o-1 : 1-By ARTHUR WILLIAM CROSSLEY and CHARLES GILLING (Salters’Fellow).IT has been previously shown (Trans., 1909, 95, 19; Proc., 1909,25, 96) that 5-chloro-l : l-dimethyl-A4-cycZohexen-Sone (I) can becondensed with the sodium derivative of ethyl malonate (or sub-stituted ethyl malonates) to form ethyl 1 : l-dimethyl-A4-~ycZohexen-3-one-5-acetate (11) with elimination of a molecule of ethyl car-bonate :dimethyl- A4-cyclohexen- 3 -one.CMe& CH2-C*>CH B, c c1 + NaCR(C02Et), + EtOH =(1.1CMe,<CH2,C>CH CH *CO + CO(OEt), + NaCl2 1ROCK* C0,Et(11.)These condensation products, on hydrolysis, give rise to a seriesof hydroaromatic ketones according to the following scheme, inwhich R=H, Me, or Et; R,=Me, Et, or Pr:CMe2<gEizg>CH + HOH = CMe2<CHi--q>CH CH -CO + CO, + EtOH.I IR*bH*CO,Et R,It was also mentioned (Zoc.cit., Trans., p. 27) that a smallquantity of a nitrogenous substance, melting at 141°, was alwaysformed together with the condensation products of type 11, due tothe presence of ethyl cyanoacetate in the ethyl malonate employed.In continuance of the investigations on the chemical reactivity ofthe chlorine atom in chlorodimethylcyclohexenone, the latter sub-stance was next condensed with the sodium derivative of ethylcyanoacetate, when the substance melting at 141O is formed inabout 75 per cent. of the theoretical quantity. It gives analyticalnumbers agreeing with the formula C,,H,,O,N, and it was at firstthought that the reaction should be formulated on similar lines tothat taking place between ethyl malonate and chlorodimethylcyclo-hexenone :NaCON 5-CHLORO-I : 1-DIMETHYL-A4--CYCLOHEXEN-3-ONE. 519This assumes that in such reactions ethyl malonate and ethylcyanoacet ate behave as if they possessed similar constitutions.Thechemical properties of the condensation product are not, however,in agreement with those which a substance having formula (111)should exhibit ; for whereas ethyl dimethylcyclohexenoneacetate(11) is it perfectly neutral compound containing a ketonic group,as proved by the fact that it readily forms a semicarbazone, thesolution of the ethyl cyanoacetate condensation product in aqueousalcohol has well-marked acidic properties, may be titrated againststandard sodium hydroxide solution, and the neutral solution soobtained gives a green colour with ferric chloride.Moreover, it canbe readily esterified with ethyl alcohol containing 5 per cent. ofsulphuric acid, giving rise to a mixture of two ethyl derivatives,which can be separated by fractional crystallisation, and since theyboth possess the same general formula, the same molecular weight,and yield the same product on hydrolysis, it seems evident that theyare stereoisomeric substances.In a similar way two stereoisomeric methyl derivatives have beenprepared.The substance melting a t 1 4 1 O cannot be hydrolysed by long-continued boiling with an alcoholic solution of potassium hydroxide,probably on account of the stability of the potassium salt formed,but when heated for an hour with concentrated hydrochloric acid,it is converted into 1 : 1 : 3-trimethyl-A4-cycZohexen-3-one (IV), areaction which may be provisionally represented as follows :CMe,<CH220>CH -+ CMe2<CH,--C>CH CH,*CO -3CH2 yCN* CH* C0,Et HO,C*&H*CO,H *(111.)(IV. 1The marked acidic properties of the condensation product (111)of ethyl cyanoacetate and chlorodimethylcyclohexenone cannot beascribed to the presence of the hydrogen atom attached to the carbonatom, marked with an asterisk, situated between the cyanogen andcarbefhoxyl groups.Por, apart from the extreme ease with whichesterification can be effected, it is found that when either of thetwo ethyl derivatives is boiled for an hour with concentratedhydrochloric acid, hydrolysis takes place, and trimethylcydo-hexenone (IV) is produced; whereas if the conc;titution of theoriginal substance is represented by formula 111, the ethy520 CROSSLEY AND QILLING : ACTION OF ETHYL CYANOACETATEderivative (V) would give on hydrolysis 3-propyl-1 : l-dimethyl-cyclohexen-3-one (VI) :A simple explanation of the acidic properties is forthcoming ifit be assumed that the original condensation product (111) under-goes tautomeric change, the ketonic oxygen becoming enolic, andgiving rise t.0 a substance of formula (VII), which on esterification(etherification) would yield (VIII).CN*CH*CO,Et CN*CH*CO,Et(VII.) (VIII.)I n favour of this supposition is the fact that the substancemelting a t 1 4 1 O forms condensation products with aniline andmonomethylaniline.Whilst formula (111) admits of the formationof a compound with elimination, as water, of the ketonic oxygenwith the two hydrogen atoms of the amino-group in the case ofaniline, it does not admit of an analogous reaction in the case ofmethylaniline; but both reactions are easily explained by theadoption of formula (VII). It will be seen that the ethylderivative (VIII) still shows the presence of a hydrogen atomattached to the carbon atom, situated between the cyanogen andcarbethoxyl groups, and it should therefore be possible to introducea second ethyl group into this position by the successive action ofsodium and ethyl iodide. Although attempts were made to accom-plish this end under a variety of conditions, they were alwaysunsuccessful, and this, taken in conjunction with the fact thatformula (VII) does not offer a ready explanation of the formationof two stereoisomeric modifications of the ethyl and methyl ethers,necessitates some other explanation of the reaction being sought.It has been proposed by J.F. Thorpe (Trans., 1900, 77, 925) thatthe formula which most adequately explains the behaviour of thesodium derivative of ethyl cyanoacetate is (IX), and the mechanismof its condensation with unsaturated substances is as follows :CO,Et*CH:CR, + HC(CN):C<ONa OEt = CO,E t *CH2*CR2*C(CN):C<ONa OEt(IX. 1where R may be either an alkyl group or hydrogen.If, as kindly suggested to us by Dr.J. F. Thorpe, this formulfor ethyl cyanoacetate be applied in the reaction under discussion,the following representation is arrived a t :CH*CO '4'CMe2<CH2*C(OH)>CH t- Or CMe2<CH;-C>CH28( CN) 0 CO,E t E CH,--C(CN)*CO,Et(XI.) (X.)and the product would be ethyl 3-hydroxg-1: l-dimethyl-A3-cyclo-hexenylidene-5-cyanoacetate (XI) (ethyl 1 : l-dintethylcyclohexan-3-onylidene-5-cyanoacetate, X).Such a formula appears to account for all the observed propertiesof the substance, for example, the formation of condensationproducts with aniline and methylaniline ; its marked acidic pro-perties, and the formation of two isomeric methyl and ethylderivatives, which would be represented as cis- and trans-modifica-tions :/\C'0,Et CN/\CN C0,EtThe question naturally arisw, Have the two corresponding cis-and t ram-f orms of ethyl hydroxydimethylcyclohexenylidenecyano-acetate been observed? This isexplained by assuming that the two forms (X) and (XI) aretautomeric, and a hydrogen atom is alternating between the twopositions shown, which would preclude the possibility of fixedisomerism. The introduction of an ethyl group into the moleculecauses the cessation of this mobility of the hydrogen atom, andhence fixed isomerism makes its appearance.This idea correspondswith that advanced by J. F. Thorpe (Trans., 1905, 87, 1669) toaccount for the fact that glutaconic acid cannot be isolated incis- and tram-modifications, whereas its dialkyl derivatives, inwhich the double bond becomes fixed, are capable of existing inthe two forms.We take this opportunity of expressing our cordial thanks toMr.E. C. C. Baly and Dr. Tuck, who have examined ethylhydroxydimethylcyclohexenylidenecyanoacetate and its two isomericethyl ethers spectroscopically, and who have been kind enoue;h tomake the annexed diagram and report.The answer is in the negative522 CROSSLEY AND GILLING: ACTION OF ETHYL CYANOACETATE" The absorption spectra of ethyl hydroxydimethylcyclo-hexenylidenecyanoacetate and its two ethyl ethers were examinedin alcoholic solution, and, as can be seen from the diagram, theyshow very persistent bands. The absorption of the two isomericethyl ethers is identical, and exhibits a band with its head atUscilZation frepwicies.21 26 28 3000 32 34 36 38 4OOo 42 44Ethyl elher (both isomcrides).EthyZ hydroxydimcth~lcyclohe~c?a2/1i~enec~a?~oncetnte.9 9 J ? j # an _ I ._ _ _p T ~ S C ~ L C C of soditma ethoxide1/~=3100. The parent substance shows a band with its head a tl/h=2950, whilst in the presence of sodium ethoxide the bandis shifted to 1 / A = 2700. This shift towards the red, on the additionof alkali, is analogous to the case of dimethyldihydroresorcin, whichtherefore affords evidence that labile tautomerism occurs. Sincethe absorption band of the parent substance is nearer to the reON 5-CHLORO-1: 1-DIMETHY L-A4-CYCLOHEXEN-3-ONE. 523than in the case of the two ethyl ethers, the conclusion may a tonce be drawn that the hydrogen atom of the former is labile, whichexplains why the parent substance cannot be resolved into cis-and trans-modifications.That the shift in the absorption, on theaddition of alkali to the parent substance, is due to the presenceof labile tautomerism is proved by the fact that no change isproduced by the addition of alkali to either of the ethyl ethers.”The following considerations also support the conclusion that thesubstance is ethyl hydroxydimethylcyclohexenylidenecyanoacetate.As already mentioned, when chlorodimethylcyclohexenone is con-densed with ethyl malonate (or substituted ethyl malonates), oneof the carbethoxyl groups is always eliminated as ethyl carbonate(see p. 518). Several instances of the production of the lattersubstance in condensation reactions have been recorded, one ofthe most recent being in the interaction of ethyl sodiocyanoacetateand ethyl 1 -cyanocyclopropane-1-carboxylate :vH2>C(CN)*C0,Et + CN*CHNa*CO,Et + EtOH =CH,and Best and Thorpe (Trans., 1909, 95, 693) consider that theelimination of ethyl carbonate is determined, in all such cases, byspatial considerations.The present experiments lend considerablesupport to this view, for, in the first place, the yields of condensationproducts formed from chlorodimethylcy clohexenone and the sub-stituted ethyl malonates diminished rapidly with increasing mole-cular weight, from which it would appear that the overcrowding inthe molecule, caused by the introduction of heavier alkyl groups,renders the formation of the condensation products more and moredifficult.This affords a possible explanation of the reason for the non-acidity of ethyl dimethylcy clohexenoneacetate (XII) and the acidityof ethyl hydroxydimethylcyclohexenylidenecyanoacetate (XIII), forin the initial product of interaction (XIV) of ethyl malonate andchlorodimethylcyclohexenone, the carbon atom marked * may beregarded as overweighted and the molecule overcrowded in theregion occupied by these groups, with the result that ethyl carbonateis eliminated :CMez<CH2-C>CH CH *CO + EtOH = CMe,<CH2-c>CH CH *CO + CO(OEt),2 1 Hb(CO,Et), H2C*C0,E t(XIV.) (XII.)Why, then, does not a similar elimination of ethyl carbonat524 CROSSLEY AND GILLING : ACTION OF ETHYL CYANOACETATEtake place from the condensation product (XV) formed from ethylcyanoacetate and chlorodimethylcy clohexenone ?C(CN)*CO,EtC(CN)*CO,Et(XIII.)In this case the carbon atom marked * is not so weighted asin the substance with formula (XIV), the CN group being muchlighter than a C0,Et group, and hence the wandering of thehydrogen atom attached to this carbon atom into the ring, withformation of ethyl hydroxydimethylcy clohexen y lidenecyanoacetate(XIII), sufficiently reduces the overcrowding to give a stablesubstance.If, however, this hydrogen atom be replaced by a methyl group.as in the condensation of ethyl methylcyanoacetate and chlorodi-methylcyctohexenone, then the carbon atom * (XVI) is again over-weighted, and as a result ethyl carbonate is eliminated:CMe2<Ca2-c>CH CH -GO + EtOH = CO(OEt), + CMe2<E2zg>CH -+2 1 IMe*c( CN) * C0,Et MW CH-CNjrXVI.) (XVII.) CH,*C(OH)>(33CMe2<CH2- 8 Me*C*ClS(XVIII.)But the product so formed (XVII) is still overcrowded, and ithydrogen atom wanders into the ring, giving hydrozydim8etlbyl-cycloh exenyliden epropionit rile (XVIII).In view of these results, it seemed of interest to examine theinteraction of ethyl acetoacetate and chlorodimethylcyctohexenone,when it was found that the product is the same as when usingethyl malonate, that is, ethyl dimethylcyclohexenoneacetate (XIX).Here also the initial condensation product (XX) contains the over-crowded carbon atom, marked with a, *, and as a consequence theacetyl group attached to it is eliminated, by interaction with ethylalcohol, as ethyl acetate, and a hydrogen atom takes its place.The action of acid hydrolysing agents on ethyl hydroxydimethyl-cyclohexenylidenecyanoacetate can now be easily explained.TheC0,Et group (or the CN group) is first converted into C0,ON 5-CHLORO-1: 1-DIMETHYL-A4-CY CLOHEXEN-3-ONE. 525(XXI), and a t once carbon dioxide is evolved, giving a substanceC M e 2 < ~ ~ : ~ ~ > C H + EtOH =kHAc*CO,Et(XX.)CH,*CO,Et + CMe,<cH2-9>CH CH,*CO~ CH,*CO,Et(XIX.)(XXII) which rearranges itself to dimethylcy clohexenoneaceto-nitrile (XXIII) :--+The CN group in the latter compound is then hydrolysed toCO,H, carbon dioxide is eliminated, and trimethylcyclohexenone(XXIV) produced.The acid hydrolysis of the methyl or ethylethers of ethyl hydroxydimethylcyclohexenylidenecyanoacetate takesplace in a similar way, but the action of alkaline hydrolysing agentson these substances is of quite a different nature. When eitherof the two ethyl ethers is heated with an ethyl-alcoholic solution ofpotassium hydroxide, the carbethoxy-group is attacked, yieldinge th o xydime t hylcycloh exen y lid enrecyanoacet i c acid (XXV) , meltinga t 149O, which acid should exist in cis- and trans-forms, correspond-CMe2<CH~-C/CH CH *C(OEt)+(XXV.)ing with the two ethyl esters. These modifications have not,however, been isolated, as no matter which of the two esters ishydrolysed, one and the same product is obtained; and it can onlybe concluded that, under the influence of the hydrolytic agent, theless stable form of the acid is converted into the more stable form,such cases being common among hydroaromatic substances.When either of the methyl esters of ethyl hydroxydimethylcyclo-hexenylidenecyanoacetate is hydrolysed with methyl-alcoholicpotassium hydroxide, m~ethoxydimethylcyclohexenylidenecyano-a c e t i c a c i d (XXVI), melting at 174O, is produced; but when thehydrolysis of the methyl ethers is carried out in ethyl-alcoholicCN*&CO,526 CROSSLEY AND GILLIKG : ACTION OF ETHYL CYANOACETATEsolution, ethoxydimethylcyclohexenylidenecyanoacetic acid (XXV),melting a t 149O, is formed. The ease with which the methyl groupCMe2<CHi CH *C(OM ')>CHCN-C*C02H(X XVI.)is replaced by ethyl is quite remarkable. An exactly similarphenomenon is observed when either form of ethoxydimethylcyclo-hexenylidenecyanoacetate is hydrolysed with methyl-alcoholicpotassium hydroxide, the ethyl group being replaced by methyl,with production of methoxydimethylcyclohexenylidenecyanoaceticacid, melting at 174O. Such replacements of ethyl by methyl andvice versa in esters have been frequently recorded (compare Purdie,Trans., 1885, 47, 855; 1887, 51, 627; 1888, 53, 391; 1891, 59,468). When ethoxydimethylcyclohexenylidenecyanoacetic acid isheated a few degrees above its melting point, carbon dioxide isevolved, and 3-ethoxg-1: l-dirnethyl-b3-cyclohexenylidene-5-aceto-nitrile (XXVII) is formed:EC M ~ , < ~ ~ * ~ ( ~ ~ ~ > G H -+ C M ~ , < ; ~ ~ + C H~!H=CN bH3(XXVII.Although somewhat stable towards alkalis (see page 532), thisnitrile is readily hydrolysed by acids, with formation of trimethyl-cyclohexenone.EX PER I MENTAL.Forty-eight grams (1 mol.) of chlorodimethylcy clohexenone weregradually added to a mixture of 70 grams (2 mols.) of ethylcyanoacetate and 13-8 grams (2 atoms) of sodium dissolved in 170C.C.of absolute alcohol, when a vigorous reaction a t once commenced,and the liquid turned red. After heating in a water-bath for sixhours, the product was poured into water and extracted four timeswith ether." The aqueous alkaline liquid was then acidified withsulphuric acid, extracted four times with ether, and the etherealsolution washed, dried, and evaporated.The solid residue, weigh-ing 51 grams after drying on porous plate, was purified bycrystallisation, first from benzene, then from aqueous methyl alcohol,and analysed :* On evaporating the ether, a residue was obtained, which was proved to consistprincipally of unchanged ethyl cysnoacetate and a resinous product, which yielded asolid, crystallising from methyl alcohol in fine white needles, melting at 57", but intoo small an amount for complete investigationON 5-CHLORO-1: 1-DIMETHYL-A4-CY CLOHEXEN-3-ONE. 5270-1081 gave 0.2637 CO, and 0.0745 H,O. C=66*53; H=7*66.0.2905 N=5.63.C13H17O3N requires C = 66.38 ; H = 7-23 ; N = 5-95 per cent.Ethyl 3-hydroxy-l : l-dimethyl-A~-cyclohexenylidene-5-cyanoacet-ate, I (ethyl 1 : 1-dim e t hylcycloh exan-3-onylidene-5-cyanoac et at e,,, 13-8 C.C.N, (moist) at 13O and 762 mm.(1.1 (11.)II), is easily soluble in the cold in acetone, chloroform, alcohol, orethyl acetate, and crystallises froin benzene or aqueous methylalcohol in fine white, glistening needles, melting a t 141O. It giveswith ferric chloride in alcoholic solution a fine emerald-greencolour, slowly fading to olive-green, a process which is hastened bywarming, and with ferric chloride in neutral solution it forms adark greeneprecipitate. It has a marked acid reaction in aqueoussolution, and can be titrated with potassium hydroxide solution,when it behaves as a monobasic acid:0.2412 required 10.4 C.C.NI10-KOH. Calculated, 10.3 C.C.Found, M.W. = 232. C13H,,03N requires M.W. = 235.The silver salt, prepared in the usual manner, is a yellow,amorphous precipitate, which darkens rapidly on exposure to airand light:0.2618 gave 0'0828 Ag. Ag=31*62.C,,H,,O,NAg requires Ag = 31.58 per cent.Ethyl 3-anilino-1 : l-dim~thyl-A3-cyclohexenyl~dene-5-acetate, pre-pared by heating ethyl hydroxydimethylcyclohexenylidenecyano-acetate with aniline, is readily soluble in acetone, alcohol, or aceticacid, insoluble or only slightly soluble in light petroleum, benzene,or chloroform, and crystallises from methyl alcohol in felted massesof long, feathery, golden-yellow needles, melting at 197O :02006 gave 14.6 C.C. N, (moist) at 6O and 752 mm.C19H2202N, requires N = 9.03 per cent.Et hy I 3-met hylanilino-l : 1-dim e t h yLA3-cycloh exenylidene-5-c yano-acetate was prepared in a similar manner, using methylanilineN=8-77.instead of aniline.transparent, flattened, yellow crystals, melting at 183O :It separates from methyl alcohol in small28 CROSSLET AND OILLING : ACTION OF ETHYL CYANOACEI'AZ E0.2135 gave 15.2 C.C.N, (moist) a t 8O and 764 mm.C2,,H2402N2 requires N = 8.64 per cent.N=8.64.Hydrolysis of Ethyl Hydroxydin~ethylcyclohexenylidenecyano-acetate.Ten grams of the ester were boiled with 100 C.C. of concentratedhydrochloric acid for six hours, when the solid slowly dissolved andan oil separated. The liquid was then diluted with water, extractedwith ether, the ethereal solution washed, dried, and evaporated, andthe residue distilled under a pressure of 23 mm., when nearly thewhole (5.5 grams) distilled at 100-103°.It possessed the charac-teristic odour of trimethylcyclohexenone (b. p. 109O/32 mm., com-pare Trans., 1909, 95, 24), and its identity with this substance wasestablished by preparing from it the oxime, which melted a t 78O,and the semicarbazone, which melted at 193O (N = 21-55 ; C,,H,,ON,requires N=21.54 per cent.). The melting points of the abovederivatives remained unaltered on mixing with an equal quantityof the corresponding substances prepared in the manner previouslydescribed (Zoc. cit.):Esterification of Ethyl Hydroxydim~ethylcyclohexenylidenecyano-acetate.-1. H7ith Methyl Alcohol and SuZphu~ic Acid.Ten grams of the hydroxy-compound were heated on the water-bath with 100 C.C.of a 5 per cent. solution of sulphuric acid inabsolute alcohol for three hours. The whole was then poured intowater, extracted four times with ether, the ethereal solution washedwith a dilute solution of sodium hydroxide to remove traces ofunesterified material, then with water, dried, and evaporated. Thesolid residue (10 grams) was separated by fractional crystallisationfrom light petroleum (b. p. 60-80O) into two isomeric substancesA and B, melting respectively a t 79O and 90°. No very exactfigures can be given as to the relative proportions in which thesetwo esters are formed, but A predominates, probably to the extentof five to six times the amount of B.Ethyl 3-methoxy-1 : l-dimethyl-A3-cyclohexeny~idene-5-cyanoacet-ate (A) separates out first, crystallising very readily in small,CMe,<CH;-- CHo*c(oM$>cH&CN)*CO,E~white, elongated needles, melting at 79O :0.1255 gave 0.3112 CO, and 0.0869 H,O.C=67*62; H=7.69.C,,H,,O,N requires C = 67.47 ; H = 7.63 per cent.The isomeric ester B is contained in the mother liquors of A, andON 5-CHLORO-1 : I -DIMETHYL-AS-CYCLOIIEXEN-3-ONE. 529after repeated crystallisation, separates in thin, white flakes, meltinga t 90°:0.1486 gave 0.2696 CO, and 0-1022 H,O. C = 67.83 ; H = 7.64.Cl4HI9O3N requires C?= 67.47 ; H = 7.63 per cent.2. With Ethyl Alcohol and Sulphuric Acid.Ten grams of the hydroxy-compound were esterified exactly asdescribed above, using ethyl instead of methyl alcohol, when 12.5grams of a mixture of two esters were obtained, which were separatedby fractional crystallisation from methyl alcohol into two sub-stances, A and B, melting respectively a t 106O and 97O.Therelative proportions produced are much the same as in the case ofthe methyl esters, the isomeric form A predominating in amount.Ethyl ethoxy-1 : l-dintethyl-L\3-~yclohexenylidene - 5 - cyanoacetate(A) crystallises from methyl alcohol in small, white needles, orfrom light petroleum (b. p. 60-80O) in clusters of beautifulelongated, prismatic needles, melting at 106O :0.1280 gave 0-3215 CO, and 0-0958 H20.0.3218The molecular weight was determined by the cryoscopic method,C = 68.60 ; H = 8.31.N=5.53.C15H,,03N requires C = 68-44 ; H = 7.98 ; N =5*32 per cent.,, 15.2 C.C.N, (moist) at loo and 744 mm.using benzene as solvent :Found, M.W. = 235. C15H2103N requires M.W. = 263.This ester has also been prepared by the action of ethyl iodide onthe sodium salt of ethyl hydroxydimethylcyclohexenylidenecyano-acetate in alcoholic and in benzene solution; but the amount ofpure material produced was very small, resinous products beingformed, and under the conditions employed it was not foundpossible t o isolate any of the isomeric ester melting a t 97O.The isomeric ester B, obtained from the mother liquors of A,crystallises from methyl alcohol in lustrous, transparent prisms,melting at 97O:0.1035 gave 0.2606 CO, and 0.0758 H20. C=68-66; H=8*14.The molecular weight, determined by the same method as usedin the case of the isomeric ester, was found to be 236.Although the observed values for the molecular weights of thetwo esters do not show as close an agreement with the theoreticalvalue as might be desired, they are nevertheless of the same order,and serve to prove that the isomerism of these two substances isnot due to the formation of complex molecules, but is in allprobability a case of cis- trans-isomerism.C1SH2103N requires C = 68.44 ; I3 = 7.98 per cent530 CROSSLEY AND GIILLlXG : ACTION OF ETHYL CYANOACETATEHydrolysis of Ethyl Methoxydi~methylcyclohexerzylidenecyarzo-acetate.Experiment showed that the same substance (m.p. 174O) was thesole product obtained when either of the esters, melting respectivelya t 79O and 90°, was hydrolysed with methyl-alcoholic potassiumhydroxide, and therefore, for the purpose of investigating thenature of the substance melting at 174O, there was no object in firstseparating the two esters by the tedious process of fractionalcrystallisation. Four grams of the mixture of thc two isomericesters were therefore heated for two hours on the water-bath with3 grams of potassium hydroxide dissolved in 60 C.C.of absolutemethyl alcohol, when the solution was diluted with water andextracted once with ether, to remove any traces of unaltered ester.The aqueous solution was next acidified with sulphuric acid,extracted three times with ether, and the ethereal solution washed,dried, and evaporated.There resulted 3 grams of a solid, whichwas purified by crystallisation from dilute methyl alcohol, andanalysed :0.1380 gave 0.3318 CO, and 0.0841 H20.Cl2Hl5O3N# requires C = 65.16 ; H= 6.78 per cent.3-Methoxy-l : l-d~m.ethyl-A3-cyclohexenylidene-5-cyanoacetic acid,C= 65-57 ; I3 = 6-77.C( CN) -CO,Hcrystallises from dilute methyl alcohol in masses of irregular plates,melting at 174O. A t 179O a steady evolution of carbon dioxideoccurs, with production of methoxydimethylcyclohexenylideneaceto-nitrile (compare the hydrolysis of the corresponding ethoxy-derivative, p. 531).The presence of a methoxyl group in this acid was confirmed bya Zeisel determination :0.2353 gave 0-2424 AgI. OMe=13*6.C12H1503N requires 'OMe = 14.00 per cent.It is interesting to note that when the hydrolysis of ethylmethoxydimethylcyclohexenylidenecyanoacetate is carried out inethyl-alcoholic solution, the methyl of the methoxyl group isreplaced by an ethyl group, the product being ethoxydimethyl-cyclohexenylideneacetic acid, melting a t 149O (compare p.531).Hydrolysis of Ethyl EthoxydimethyZcyclohexerzyZidenecyanoacetate.The following experiments were carried out both with the esterA, melting at 106O, and with the ester B, melting at 97O, and aON 5-CHLORO-1 : 1-DIMETHYL-A4-CYCLOHEXEN-3-ONE. 531the products of hydrolysis are the same, no matter which of thetwo isomerides is employed, the description of the experimentsapplies to either of them.1. TVith fIpdrochlor.ic ,4cid.-Eight and &half grams of the esterwere heated with 100 C.C.of concentrated hydrochloric acid undera reversed condenser for five hours, when, after extracting withether and working up in the usual way, 5 grams of an oil wereobtained, boiling a t 104-10‘7O/ 25 mm. This fraction was identifiedas trimethylcyclohexenone by preparing from it the semicarbazone,which melted a t 193O, and the oxime, which melted at 77-78O.2. With Potassium Hydroxide.-Twenty-four grams of the esterwere heated for two hours on the water-bath with 15 grams ofpotassium hydroxide dissolved in 200 C.C. of ethyl alcohol (ifmethyl alcohol is employed instead of ethyl alcohol, methoxydi-methylcyclohexenylidenecyanoacetic acid is the product), and theproduct worked up as described in the case of ethyl methoxy-dimethylcyclohexenylidenecyanoacetate (see page 530 j, when a solidwas obtained; which was crystallised from aqueous alcohol andanalysed :0.1114 gave 0.2718 CO, and 0.0731 H20.C = 66.54 ; H = 7.29.0.2009 ,, 9.4 C.C. N2 (moist) at 8O and 752 mm. N=5.59.C,,H170,N requires C = 66-38 ; H = 7-23 ; N = 5-95 per cent.3-Ethoxy-1: l-dimethyZ-L\3-cyclohexenyZ~ene-5-cyanoacet~c acid isreadily soluble in all the ordinary organic solvents, except lightC(CN)*CO,Hpetroleum. It crystallises from aqueous methyl or ethyl alcoholin clusters of minute needles, which melt and decompose a t 149O,gas being steadily evolved a t 153O.The molecular weight was determined by titration againststandard potassium hydroxide solution, using phenolphthalein asindicator :0.1901 required 7.92 C.C.fl/lO-KOH. Calculated, 8.09 C.C.Cl,H170,N requires M.W. = 235. Found, M.W. = 240.3-Ethoxy-1: 1-d~m~et?~y~-A3-cycloTtezenyl~dene-5-aceton~tde was pre-pared by heating 5 grams of ethoxydimethylcy clohexenylidene-cyanoacetic acidmelting point ofVOL. XCVII.under diminished pressure. A little above thethe acid, carbon dioxide was given off, and as532 CROSSLEY AND GILLING : ACTION OF ETHYL CYANOACETATEsoon as the evolution had ceased, the residual liquid was distilled,when the whole (3.7 grams) boiled a t 162--164O/18 mm.:0.2272 gave 13-2 C.C. N, (moist) a t 8O and 768 mm.C,,H170N requires N = 7.32 per cent.The pure substance is a colourless, highly refractive, oily liquid,boiling at 163O/18 mm., and possessing an odour of hydrocyanicacid.A Zeisel determination, carried out according to Perkin'smodified method, gave the following result :N=7-10.0.2468 gave 0.2745 AgI. OEt=21.3.C,,H,,ON requires OEt = 23.5 per cent.This result is somewhat low, but various investigators havefound that ethoxyl determinations generally come out from 1 to2 per cent. below the calculated figure.The nitrile is only very slowly attacked by potassium hydroxidein alcoholic solution, giving a small amount of a substancecrystallising from a mixture of chloroform and light petroleum,melting a t 130°, and giving, on analysis, numbers agreeing with aformula C,,H,,O,N. It is probably, theref ore, hydroxydimethyl-cyclohexenylideneacetamide (I), or, as it is devoid of any acidnature, it may be this substance in the isomeric ketonic form (11).CMe,<zE: C(oH)>CH CMe,<CH;-&w CH *CO(1.1 (11.1When heated with concentrated hydrochloric acid, 8.5 grams ofthe nitrile gave 5 grams of a liquid having a camphoraceous odour,and boiling constantly a t 105O/25 mm. This substance wasidentified as trimethylcyclohexenone by preparing the oxime, whichmelted a t 78O, nor was this melting point lowered by admixturewith an equal quantity of the oxime of pure trimethylcyclo-hex en one .H 8 - co N IT, E HC*CO*NH,Action of Ethyl Methylcyanoacetate on Chlorodimethylcyclo-hexenone.Ethyl methylcyanoacetate was prepared by the interaction ofethyl sodiocyanoacetate and methyl iodide, according to the direc-tions of Auwers (dnnalen, 1895, 285, 283).The product, althoughstated by Auwers to be pure (N = 10.93 ; calculated, 11.02 per cent.),boiled for the most part at 190--195O, and subsequent experimentsshowed that it undoubtedly contained considerable amounts ofethyl cyanoacetate and also ethyl dimethylcyanoacetate, which sub-stances, if present in equivaleut amounts, would account for thecorrect value for nitrogen quoted by AuwersON 5-CHLORO-1 : 1-DIMETHY L-A4-CYCLOHEXEN-3-ONE. 533Twenty-four grams of chlorodimethylcyclohexenone were addedto a mixture of 39 grams (2 mols.) of ethyl methylcyanoacetate and7 grams of sodium (2 atoms) dissolved in 42 C.C. of absolute ethylalcohol. After heating on a water-bath for six hours, the reactionmixture was poured into water, extracted four times with ether(aqueous solution =A), the ethereal solution washed, dried,evaporated, and the residual liquid distilled in a current of steam,when all but a negligible quantity of a sticky resin passed over.The distillate, after extraction with ether, etc., yielded 24 gramsof a liquid, which, after repeated fractionation, gave two mainportions of about equal weight, boiling at 126-127O and190-195O, the latter consisting of ethyl methylcyanoacetate.The fraction 126-12707 from its odour and boiling point,appeared to be ethyl carbonate, and its identity with that substancewas established by analysis :0.1406 gave 0.2629 C02 and 0.1068 H,O.C,H,,03 requires C =50*85 ; H = 8-47 per cent.The above-mentioned aqueous alkaline solution A was acidifiedwith sulphuric acid, extracted with ether, and, after working up inthe usual manner, yielded 32 grams of a viscid, oily liquid, which,after some time, partly solidified.The solid (5 grams) wasseparated by spreading on porous plate, and, after crystallisationfrom benzene, melted at 141°, nor was this melting point alteredon mixing with ethyl hydroxydimethylcyclohexenylidenecyano-acetate (see p. 528). The formation of this ester is undoubtedlydue to the unchanged ethyl cyanoacetate contained in the ethylmethylcyanoacetate employed.The oil, recovered from the porous plate by extraction withether, did not further solidify, and could not be distilled, evenunder diminished pressure, without decomposing.It was theref oreesterified by boiling for four hours with 300 C.C. of ethyl alcoholcontaining 5 per cent. of sulphuric acid. The resulting solutionwas worked up as already described, and the residue (18 grams)distilled under 32 mm. pressure, when the following fractions werecollected :C = 50.99 ; H = 8.44.100-150° = 3.7 grams;170-195O = 6.5 grams;150-170° = 0.4 gram ;195-220° = 2.4 grams.The fraction 100-150° consisted principally of ethyl dimethyl-malonate, for on hydrolysis it yielded dimethylmalonic acid, meltingat 193O with evolution of gas :0.1088 gave 0.1824 CO, and 0.0597 H,O.The presence of ethyl dimethylmalonate proves that the originalC =45*72 ; H = 6-10.C,H,O, requires C = 45.45 ; H = 6-06 per cent.N N 534 CROSSLEY AND GILLING : ACTION OF ETHYL CYAKOACETATEethyl methylcyanoacetate must have contained some ethyl dimethyl-cyanoacetate.The fruction 170-195O, on redistillation, passed over as a paleyellow, refractive, oily liquid, and although it did not boil veryconstantly (170-180°/ 27 mm.), analysis and subsequent hydrolysisproved it to consist of 3-ethoxy-1 : l-dimetl~yl-h3-cyclo~~exen ylidene-5-propionitrile :0.1145 gave 0.3178 C02 and 0.0951 H,O.C,,H,,ON requires C = 76.09 ; H = 9.26 per cent.The mechanism of the reaction giving rise to the correspondinghydroxydimethylcyclohexenylidenepropionitrile has been alreadyexplained (see p.524).Seven grams of the above nitrile were heated with 100 C.C. of con-centrated hydrochloric acid for five hours under a reversed con-denser.The product was poured into water, extracted four timeswith ether, the ethereal solution washed first with sodium hydroxidesolution, then with water, dried, evaporated, and the residue(5 grams) distilled, when it boiled constantly a t 119*5O/25 mm.as a colourless, refractive liquid, which proved to be dimethylethyl-cyclohexenone (compare Trans., 1909, 95, 28), the formation ofwhich substance takes place in accordance with the followingscheme :C = 75.70; H =9.23.CMe,<ci+- CH 'c(0E2>CH -+ CMq<cH, CH2*C(oH) c> CH -+I I C H, 80 CN CH,*C* C 0,HCH, *OH,0.1371 gave 0.3952 CO, and 0.1312 H,O.C,,H,,O requires C = 78.94 ; H = 10.53 per cent.The oxime, prepared in the usual manner, is a viscid, oilyliquid, boiling a t 153O/28 mm., and solidifying on cooling toradiating clusters of flattened, transparent needles, melting at43-45O. It is so readily soluble in all the ordinary organicsolvents that it was found to be most easily purified by distillation:C = 78.61 ; H = 10.63.0.1921 gave 14 C.C.N, (moist) at 18O and 763 mm.Cl,H170N requires N = 8-38 per cent.As this oxime has not been previously described, a specimen waamade for the purpose of comparison from pure dimethglethylcyclo-hexenone, obtained in the manner formerly described (Zoc. cit.).N=8.45ON 5-CHLORO-1: I-DIMETHYL-A4-CYCLOHEXEN-3-ONE. 535It was found to possess properties identical with the above-mentioned oxime.After onecrystallisation from benzene, it melted a t 106O, and proved to beethyl ethoxydimethylcyclohexenylidenecyanoacetate (see page 529).It was mentioned on page 533 that when the aqueous alkalineliquid A was acidified with sulphuric acid, 5 grams of ethylhy droxy dimethylc y clo hexen ylidenecyanoacetat e separated, but evi-dently this separation is not a complete one, and the unalteredmaterial is converted into its ethyl ether (M.p. 1 0 6 O ) during theprocess of esterificatiori to which the residue was submitted.The fraction 195-230° solidified after some time.Action of Ethyl Acetoacetate on Chlol.o~~inetlz?/lcyclo~~exenone.Fifty-two grams (2 mols.) of freshly distilled ethyl acetoacetatewere mixed with a solution of 9.2 grams of sodium (2 atoms) in110 C.C. of absolute alcohol, and 32 grams (1 mol.) of chloro-dimethylcyclohexenone added. The resulting red liquid wastransferred to two soda-water bottles, which were securely corked,and then heated in a boiling-water bath fof two hours. Thereaction mixture was poured into water, extracted five times withether, and the ethereal solution washed, dried, and fractionated,using a Young’s rod-and-disk still-head. When the ether hadpassed over, a small quantity of a liquid boiling a t 65-70°(residue = A) was obtained, which, after further purification, wasproved to consist of ethyl acetate,The residue A was distilled in a current of steam to removeunaltered ethyl acetoacetate, and the non-volatile portion extractedthree times with ether, the ethereal solution dried and evaporated,and the residue distilled, when nearly the whole (18 grams) passedover a t 181°/27 mm.:0.1242 gave 0.3106 CO, and 0.0972 H20. C = 68.20 ; H = 8.69.C,zH1803 requires C = 68-57 ; H = 8.57 per cent.These numbers indicated that the substance was ethyl 1: 1-di-methyl-AacycZohexen-3-oned-acetate (Trans., 1909, 95, 23), and theidentity of the two liquids was established by hydrolysing the aboveproduct with alcoholic potassium hydroxide (Zoc. cit.), when ityielded trimethylcycZohexen-3-one, boiling a t 9 9 O / 18 mm., charac-terised by the preparation of its oxime, which melted a t 77-78O.The authors take this opportunity of expressing their thanks tothe Research Fund Committee of the Chemical Society for a grantwhich has, in part, defrayed the expenses of this investigation.RESEARCH LABORATORY, PHARMACEUTICAL SOCIETY,17, BLOOMSBURY SQUARE, W.C

ISSN:0368-1645    

DOI:10.1039/CT9109700518

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

536 FINDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS ANDLVIL-The InJuence of Colloids and Fine Suspensionson the Solubility of Gases in Water. Part I.Sotubildy of Carbon Dioxide and Nitrous Oxide.By ALEXANDER FINDLAY and HENRY JERMAIN MAUDE CREIGHTON,M.A., M.Sc. (1851 Exhibition Science Scholar of DalhousieUniversity, Halifax, Nova, Scotia).FOR many years the problem of the absorption of gases, moreespecially of oxygen and carbon dioxide, by blood has claimed theattention of physiologists. In the case of oxygen the absorptionhas been regarded as being due, in greatest measure, to theformation of a, compound with the hemoglobin of the blood;whereas, in the case of carbon dioxide, the increased absorptionas compared with a corresponding salt solution has been attributedto the reputed alkalinity of the blood, and the consequent formationof carbonate and bicarbonate.In recent years, however, different investigators (compare Hoeber,Pfliiger’s Archiu, 1903, 99, 572; Parkas, ibid., 1903, 98, 551;Friedenthal, Verworns Archiv f .ullgem. Physiologie, 1904, 4, 44 ;van Westenryk, Arch. exp. Path. Pharm. SuppZ., 1908, p. 517) haveshown by different methods that blood-serum is practically “ water-neutral.” In view of these results, it seemed that possibly theabsorption of carbon dioxide by the blood had been ascribed tooexclusively to the alkalinity of blood, and it seemed not improbablethat the colloids present in blood play an important r81e (Findlayand Harby, Zeitsch. Chem. Ind. Rolloide, 1908, 3, 169; Wo.Ostwald, ibid., 1908, 2, 264).Before this view could be tested, itwas necessary to study the influence of colloids of various kinds onthe absorption of gases, since our knowledge of this depended almostentirely on the few experiments carried out by Geffchen (Zeitsch.physikal. Chem., 1904, 49, 298).Preliminary experiments had shown that the increased absorptionof carbon dioxide which occurred under atmospheric pressure inpresence of certain colloids was due, probably, to chemical inter-action. To obtain a deeper insight into the influence of colloids ongas solubility, it was deemed of importance ts study the solubilityunder a series of presures, and also to exclude effects due to chemicalcombination by studying the absorption of a neutral gas, nitrousoxide (with regard to the neutrality of nitrous oxide, see Geffchen,Zoc. cit., p.301). This gas was chosen because its solubility in wateris nearly the same as that of carbon dioxide. Experiments on thelines indicated were carried out during the year 1908-9, theinfluence of ferric hydroxide, gelatin, arsenious sulphide, silicic acidFINE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 537dextrin, starch, glycogen, egg-albumen, and serum-albumen, as wellas suspensions of charcoal and silica, on the absorption of carbondioxide and nitrous oxide having been investigated at pressuresvarying from about 750 mm. to 1400 mm. of mercury.Apparatus.The apparatus employed was, in its essential points, the sameas that used by Gefichen (Zoc. cit.), the manometer tube, however,being graduated and considerably lengthened to perinit of absorp-tions being carried out at pressures higher than atmospheric. Theburette was connected with the absorption pipette by means ofcapillary copper tubing, in order to impart the necessary flexibilityto the apparatus.The burette was contained in a glass mantlethrough which water was caused to circulate, the temperature beingmaintained constant within 0.lo throughout a determination.So long as the absorption of gas was allowed to take place underatmospheric pressure only, the dead space (that is, the ungraduatedportion at the top of the burette and the volume of the tubesconnecting it with the absorption vessel) does not require to betaken account of, as the initial and final conditions under whichthe gas is measured are the same. When, however, the absorptionis allowed to take place at higher pressures, the volume of the deadspace must be known.This was ascertained by measuring the totalcontraction of a known volume of gas and the volume in the deadspace, produced by a known increase of pressure.Since the gas in the measuring burette was always kept dry, thepoint of saturation of the solution with gas was approached fromthe side of least pressure only, but precautions were taken to makesure that the process of absorption at any given pressure wascomplete.The liquid used for the absorption of the gas was previously wellboiled to free it from air; or in those cases where boiling was notpermissible, the liquid was freed from air by being placed underdiminished pressure.I n all the following experiments the temperature of absorptionwas 25*0°, and the experimental error did not exceed +O-25 percent., and was in most cases less than this.The solubilitySolubility =C’alcutation of Resutts.was calculated by means of the formula,538 FINDLAY AND CREIGH'I'ON : THE INFLUENCE OF COLLOIDS ANDwhere01 = concentration of the gas in the liquid phase.vl = initial volume of the gas in the burette measured at thev2 = 6nal volume of the gas in the burette measured under theT = absolute temperature of experiment (thermostat temperature).Yl = absolut4e temperature of the gas in the burette a t thebeginning of the oxperiment when v1 wits measured.Tz = absolute temperature of the gas in the burette at the end ofthe experiment when o2 was measured.P = barometric pressure.p = increaseof prossuro as shown by the manometer.p' = vnpour pressure of the liquid in the absorption pipette at theVz = volume of the gas space in the pipette at the temperature T.V2 = volume of absorbing liquid in the pipette.The volume v2 was corrected, when necessary, for the dead spaceOP the apparatus.Considering the experimental errors of deter-mination, no correction was applied to the burette readings forcubical expansion of glass, nor were the barometric readingscorrected for temperature.cg = > ) Y ) ,, ,, gaseous phase.pressure P.pressure P + p .temperature 9'.I.--Solubility of Carbon Dioxide.The carbon dioxide employed for the following experiments wasthe commercial product, which analysis showed to contain 0.58 percent.of impurity. The following values were found for itssolubility in pure water at 2 5 O (table I) :TABLE l.--Solubilz'ty of Cm4on Dioxide in Water.Pressure (mm. Hg) ... 752 800 955 1059 1153 1351Solubility .............. 0.817 0'815 0.816 0.817 0'818 0'820Pressure ............... 743 841 955 1064 1243 1351Solubility ............... 0'816 0.817 0.817 0.819 0.819 0-820As the mean of these and a number of other determinations weobtained the value 0.817 for the solubility of the carbon dioxideemployed, the solubility being independent of the pressure withinthe limits of experimental error.The value found by Geffchenfor pure carbon dioxide was 0.826PINE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 539( a ) Ferric Hydroxide Solution.In preparing the solution of ferric hydroxide, the method recom-mended by A. A. Noyes ( J . Amer. Chem. SOC., 1905, 37, 94) wasemployed. To a molar solution of ferric chloride, molar ammoniumcarbonate solution was added until the precipitate which formed oneach addition barely dissolved. This mixture was then thoroughlydialysed, first against tap water, and finally against distilled water,until soluble salts were removed. The concentration of the solutionwas determined by precipitation of the hydroxide with ammoniumsulphate.FIG. 1.Pressure mm, Hg.Carbon dioxide and ferric hydrox:c?c.TABLE 2.-Solubility of Carbon Dioxide in Ferric HydroxideSolutions (see Fig.1).Concentration: 0.569 gram of Fe(OH), in 100 C.C. of solution.Density = 1*000.Pressure ........... 750 848 928 1015 1146 1356Solubility ......... 0.848 0.843 0'841 0'842 0.845 0.846Concentration: 0.854 gram of Fe(OH), in 100 C.C. of solution.Density = 1.003.Pressure ............ ?50 847 923 1040 1234 1322Solubility ......... 0.862 0.858 0'856 0.857 0.860 0.861Concentration: 1.277 gram of Fe(OH), in 100 ,c.c. of solution.Density= 1'005.Pressure ............ 746 841 985 1071 1133 1266Solubility ......... 0.886 0.881 0'880 0.878 0.878 0'88540 FINDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS ANDTABLE 2 (continued).Concentration: 1.661 grams of Fe(OH), in 100 C.C.of solution.Density = 1.009.Pressnre ............ 747 831 918 1002 1150 1267Solubility ......... 0.904 0.901 0.896 0 900 0.900 0'902Geffchen (Zoc. c i t . ) has stated that the comparatively rapid initialabsorption of carbon dioxide is succeeded by a slow further absorp-tion. I n our experiments this slow absorption was barelyappreciable except at higher pressures, and was, even then, notgreat.The above numbers, when plotted, show that the increase ofsolubility under atmospheric pressure is proportional to the con-centration of the ferric hydroxide.( b ) Dextrin.Itcontained a slight quantity of impurity insoluble in water, and thiswas separated from the solutions before they were used forabsorbing carbon dioxide. The solubility values are given intable 3.The dextrin employed was the purest supplied by Kahlbaum.TABLE S.-SolubiZity of Carbon Dioxide in Deztrin S o l ~ i i ~ n s .(See also Fig.2).Concentration: 3-50 grams of dextrin in 100 C.C. of solution.Density = 1.008.Pressure ........... 753 819 888 1060Solubility ......... 0T99 0,800 0.800 0.800Concentration : 5-60 grams in 100 C.C. of solution.Pressure ............ 754 806 856 971Solubility ......... 0.785 0.785 0.784 0 787Concentration : 9.50 grams in 100 C.C. of solution.Pressnre ............ 753 817 864 960Solubility ......... 0.761 0.756 0.758 0.759Concentration : 13.00 grams in 100 C.C. of solution.Pressure ........... 741 798 882 962Solubility ......... 0.746 0.741 0'742 0'745Concentration : 18.90 grams in 100 C.C.of solution.Pressnre ............ 748 846 934 1031Solubility ......... 0.715 0.710 0.713 0'716Concentration : 20.60 grams in 100 C.C. of solution.Pressure ............ 728 826 920 1008Solubility ......... 0.703 0'697 0'698 0.7001171 12620'802 0.803Density = 1.015.1078 12470.787 O*i91Density = 1.034.1115 12860.764 0.768Density = 1.040.1131 12560.749 0.751Density= 1.064.1180 13440.720 0.725Density = 1.069.1161 13560'704 0-71FINE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 541As shown in Fig. 8, the solubility diminishes in almost exactproportionality with the increase in concentration of the dextrin.( c ) Arsenious Sulphide.The arsenious sulphide was prepared by passing hydrogen sulphideinto a solution of pure arsenious oxide until the latter was saturated.The greater part of the excess of hydrogen sulphide was thenexpelled by bubbling hydrogen through the liquid, which was thenfilt,ered before being used.As colloidal solutions of arseniousFIG. 2.O*S3000‘81000.79000*7700SJ u .*ro 2 0.75000.73000.71000-6900750 850 950 1050 1150 1250 1350 1 50Pressure in r m a . Hg.Carbon dioxide and dexhin.sulphide decompose on boiling, the last traces of dissolved air wereremoved by placing the liquid under diminished pressure, althoughthis led to the formation of a very thin film on the surface of theliquid. This behaviour is similar to the formation of films on thesurface of peptone solutions observed by Metcalf (Zeitsch.physikal.Chem., 1905, 62, l), and is no doubt to be regarded similarly asan illustration of Gibbs’s principle of increased surfaceconcen trathn.The amount of arsenious sulphide in the solutions was determine542 FINDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS ANDby precipitating with hydrochloric acid and drying the precipitatea t SOo.TABLE 4.-Solubility of Curbon Dioxide in Solutions of ArseniousSulp7uide.Concentration: 0.392 gram of As,S, in 100 C.C. of solution.Density = 0.997.Pressure ............ 756 891 951 1047 1172 1259Solubility ......... 0.816 0.817 0.814 0 816 0.818 0'820Concentration : 1.410 grams in 100 C.C. of solution. Density= 1.003.Pressure ............ 756 851 972 1082 1137 1281Solubility .........0'810 0310 0'812 0.810 0 812 0.811Concentration : 2.289 grams in 100 C.C. of solution. Density = 1.007.Pressure ............ 754 853 938 1003 1068 1211Solubility ......... 0.806 0.806 0'806 0.806 0.806 0'806(d) Starch.For these experiments Kahlbaum's pure soluble starch wasemployed.TABLE 5.-SolubiEity of Carbon Dioxide in Solutions of Starch.(See also Fig. 3.)Density = 1.009.Pressure ............ 752 849 951 1050 1182 1334Solubility ...... .. 0.796 0.797 0999 0.801 0.804 0-806Concentration: 2-50 grams of starch in 100 C.C. of solution.Concentration : 5-00 grams in 100 C.C. of solution. Density= 1.016.Pressure ............ 753 840 912 1021 1198 1298Solubility ......... 0.778 0.780 0.781 0.784 0.789 0.790Concentration : 7.50 grams in 100 C.C.of solution. Density= 1.023.Pressure ............ 752 860 1016 1078 1201 1351Solubility ......... 0,762 0'764 0.767 0.769 0.772 0,774Concentration : 10.00 grams in 100 C.C. of solution. Density = 1.030.Pressure ............ 758 893 9E2 1087 1163 1337.Solubility ......... 0.750 0.753 0'754 0.756 0.759 0.760It was observed in the case of the above solutions that the timerequired to saturate the solution with gas was much greater than inmost of the other cases studied. The relation between starchconcentration and solubility is shown in Fig. 8FINE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 543( e ) Gelatin.French sheet gelatin, which was found to be free from salts, wasSolutions containing as much as 6 per cent.of gelatin were used.quite mobile at 2 5 O .FIU. 3.0'82000-8000sl u 0-78004,.,'u 60.76000.7400750 850 950 1050 1150 1250 1350 1450Pressure in mm. R g .Carbon dioxide and starch.TABLE 6.--SolumZ)ility of Carbon Dioxide in Solutions of Gelatin.See also Fig. 4.)Density = 0.999.Pressure .......... 746 825 901 1011 1184 1369Solubility ......... 0.815 0'814 0.814 0.815 0.815 0.815Concentration: 1.06 grams of gelatin in 100 C.C. of solution.Concentration : 1.68 grams in 100 C.C. of solution. Density= 1-000.Pressure ............ 740 837 938 1072 1219 1324Solubility ......... 0.819 0'816 0.816 0.816 0.817 0.817Concentration : 3.36 grams in 100 C.C. of solution. Density= 1.003.Pressure ........... 741 826 943 1068 1230 1387Solubility .........0.826 0'819 0'818 0.818 0.819 0-820Concentration : 6.09 grams in 100 C.C. of solution. Density= 1.008.Pressure ............ 746 836 936 1015 1191 1371Solubility ........ 0.835 0.827 0'824 0.824 0.825 0.826The influence of concentration of gelatin on the solubility a tatmospheric pressure is shown in Pig. 7.Although dilute solutions of gelatin quickly become saturatedwith gas, the absorption takes place more slowly in the case of themore concentrated solutions. On reducing the pressure, the gasescaped rapidly from the solution, so as to cause considerablefrothing. The question of rate of evolution of gas is, however, 544 FINDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS ANDspecial one, and, on account of its importance in various directions,will require to be investigated specially.Further, absorption of carbon dioxide appreciably lowered thegelatinising temperature of the solution, thus producing an effectsimilar to peptonisation.Whether the effect is st temporary or apermanent one, we have not yet investigated.( f ) GZycogelt.I n order to free it.from the small quantities of the salts which it contained, it wassubjected to dialysis, toluene being added to prevent putrefaction.Kahlbaum's pure glycogen was employed.FIG. 4.0 *a6000*8400 sr;;9u -I.2ru ;3 of32000*8000750 850 950 1050 1150 1150 1350 1450Pressure i n mm. H g .Carbon dioxide and gelatiit (-).Carbon dioxide and glycogen (- - -1.TABLE 7.--rS)~~t~biI?'it~ of Carbon Dwxide in h'olutions of GLycogen(see also Fig.4).Concentration: 0.34 gram of glycogen in 100 C.C. of solution.Density = 0.998.Pressure ............ 759 859 959 1132 1247 1369Solubility ........ 0.819 0.805 0*810 0.812 0.810 0'810Concentration : 0.68 gram in 100 C.C. of solution. Density = 1-000.Pressure ............ 759 842 954 1114 1277 1371Solubility ......... 0.817 0.805 0.807 0.807 0.807 0'807As it was impossible to remove all the toluene from the glycogensolutions, the experimental values of t.he solubility had to becorrected for the slight lowering of solubility produced by thetoluene. The numbers in the above table are such corrected values,but they are probably not quite so accurate as in the previouscases. We may assume, however, that the relative values at differentpressures and concentrations are unaffected by the correctionFINE SUSPENSIONS ON THE SOLUBILITY OF GASES 1N WATER.545(9) Egg-Albumen.This was prepared from fresh eggs by the improved method ofHofmeister *(J. Phgsiol., 1898,23, 130). Pure crystals were obtainedfrom the first crystalline precipitate as follows. The precipitatewas washed with three changes of half saturated ammoniumsulphate solution, which contained one part of glacial acetic acidper thousand. The crystals were then dissolved in the minimalquantity of water, and, while constantly stirring, a saturatedsolution of ammonium sulphate was added slowly until a distinctprecipitate was formed; then, in addition, further 2 C.C. of thesulphate solution were added for each 1000 C.C.of albumen solution.A t the end of several days crystals were obtained.As these crystals are not pure albumen, but contain ammoniumsulphate either in combination or in solution, they were dissolvedFIG. 5.750 850 950 1020 1150 1250 1350 1450Pressure in mna. Hg.Carbon dioxide and egg-albzrmen (-1.L’ai-bon diozidc and sert6nt-dburnen (- - -).in water and dialysed until free from ammonium salts. A smallquantity of toluene was added to prevent putrefaction.The amount of albumen in solution was determined by heatingthe solution until the albumen was completely coagulated, thecoagulum being then dried at 100° and weighed.TABLE 8.--SolubiEity of Curbon Dioxide in Solutions of E g gAlbumen (see also Fig. 5).Concentration: 0.50 gram of albumen in 100 C.C.of solution.Density= 0.999.Pressure ...... . .,.., 729 849 1004 1125Solubility ......... 0.806 0.795 0.802 0.810Concentration: 1.00 gram in 100 C.C. of solution.I’ressiire .. ...... ... 734 836 984 1089Solubility .. ,... . .. 0*800 0-784 0.794 0-8011236 13500.812 0.816Density = 1.002.07310 0’8121257 135546 FlNDLAY AND CREIGHTON : THE INFLUENCE OF COLLOlDS ANDTABLE 8 (continued).Concentration : 1-61 grams in 100 C.C. of solution. Density = 1.005.Pressure ............ 735 841 966 1123 1239 1359Solubility __....... 0.791 0.773 0.783 0.797 Os801 0.804The influence of concentration of albumen on the solubility atatmospheric pressure is shown in Fig. 7.(h) SerumAlbumen.Neutral serum-albumen was prepared from fresh ox-blood by amethod due to Pauli.The blood-serum, to which was added a0*96000-94000.92000*9000d u.cl0.88003 h;, 60*86000-8400OT32000*8000Carbon dioxide am? charcoal and silica.small quantity of toluene t o prevent putrefaction, was placed insmall parchment cells suspended in closed glass vessels filled withdistilled water. The serum was dialysed for six weeks againstdistilled water saturated with toluene. During the first three weeksthe water was changed daily, thereafter every second day. ThFlNE SUSPENSIONS ON THE SOLUl3ILITY OF GASES IN WATER. 547concentration of the solutions was determined as in the case ofsolutions of egg-albumen.TABLE 9.-Solubility of Cwbon Dioxide in Solutions of Semtni-Albumen (see also Fig.5).Concentration: 0.44 gram of albumen in 100 C.C. of solution.Density = 0.998.Pressure ............ 748 844 945 1089 1246 1415Solubility ........ 0.804 0.800 0.802 0’804 0.806 0.806Concentration : 1-29 grams in 100 C.C. of solution. Density= 1.000.Pressure ............ 744 838 966 1066 1261 1431Solubility ......... 0.779 0.7T4 0.778 0.785 OT89 0.792The influence of concentration on the solubility at atmosphericpressure is shown in Fig. 7.(i) Silicic Acid.Solutions of silicic acid were prepared by dissolving pure silicain potassium hydroxide and adding excess of hydrochloric acid.The liquid was then dialysed, first against tap water, and thenagainst distilled water, until free from chloride.TABLE lO.--Solubility of Carbon Dioxide in Solwtions of SilicirA cid.Concentration: 1-40 grams of SiO, in 100 C.C.of solution.Density = 1.000.Pressure ............ 731 829 936 1064Solubility ......... 0.822 0.819 0.816 0’816Concentration : 2-20 grams in 100 C.C. of solution.Pressure ............ 732 836 938 1038Solubility ......... 0 828 0 822 0.820 0’820Concentration: 2.80 grams in 100 C.C. of solution.Pressure ........... 731 873 960 1050Solubility ......... 0.831 0’825 0.824 0.8231193 13540 3 1 6 0.816Density= 1.002.1178 13350.820 0.820Density = 1.003.1203 13300.824 0.825I n this case the solubility-pressure curves are similar in form toThe influence of concentration on the solubility at atmosphericthose for carbon dioxide and ferric hydroxide (Fig. 1).pressure is shown in Fig.7.( j ) Suspensions of Charcoal and of Silica.Suspensions of Kahlbaum’s well-powdered bone charcoal and ofThe solubility of carbon dioxide in pure silica were employed.presence of such suspensions is given in the following table:VOL. XCVII. 0 548 FINDLAY AND CREIGHTON THE INFLUENCE OF COLLOIDS ANDTABLE 11 (see also Fig. 6).0,236 gram of charcoal in 100 C.C. Density= 1.000.Pressure ............ 743 812 909 1069 1160 1250 1372Solubility ........... 0.815 0'823 0'845 0.892 0.919 0.940 0.9500.253 gram of silica in 100 C.C. Density=1*000.Pressure ........... 748 849 962 1048 1182 1274 1359Solubility ............ 0.814 0'815 0'818 0.819 0-821 0.822 0'824FIG. 7.N0V%0 1 2 3 4 5 6 7Conmlztrcction in grams per 100 C.C.solution.In the case of charcoal suspensions, the initial comparativelyrapid absorption of gas was followed by a comparatively slowFIG. 8.0-82000*80000.78000.76000'7400 *0 2-5 5.0 7.5 10.0 12.5 15.0 17'5Concentration in grams per 100 C.C. solution.absorption lasting from six to ten hours. The solubility valuesgiven in the above table are calculated from the maximum volumFINE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 549of gas absorbed by the liquid. In the case of silica suspensions,t.he liquid quickly became saturated with the carbon dioxide, noslow absorption being observed.II.--Solubility of Nitrous Oxide.The nitrous oxide was prepared by heating pure ammoniuninitrate in a flask a t about 210-225O.Before the heat was applied,the flask was thoroughly exhausted. When the pressure of nitrousoxide in the apparatus had become equal to atmospheric pressure(a manometer was attached to the apparatus), a certain amount ofthe gas was allowed to escape into the air. The outlet to the airwi19 then closed, and the nitrous oxide caused to bubble throughsolutions of potassium hydroxide and ferrous sulphate before beingstored in a gasholder filled with brine. Before being used, it wasdried by means of calcium chloride and phosphoric oxide. Thesolubility of the nitrous oxide in water, and in water containingcolloids and suspensions, was then determined in exactly the samemanner as with carbon dioxide. The following tables contain theresults obtained.TABLE 12.-Solubility of Nitrous Oxide in Water.Pressure ............758 842 967 1041 1185 13628olubility ......... 0.592 0.593 0.592 0.593 0592 0.592Pressure ............ 758 831 997 1082 1214 1351Solubility ........ 0,592 0.593 0.592 0.593 0.594 0.592Pressure ........... 758 888 971 1091 1190 1281Solubility ......... 0.591 0'592 0'591 0.592 0.593 0.593From these and other similar determinations, the mean value ofthe solubility of nitrous oxide in water was found to be 0.592, thesolubility being independent of the pressure within the limitsinvestigated.TABLE 13.-h'ohbdity of Nitrous Oxide in Fer& HydroxideSolutions (see also Fig. 9).Concentration : 0.625 gram of Fe(OH), in 100 C.C. of solution.Density = 1.001.Pressure ............758 846 934 1010 1121 1383Solubility ......... 0.590 0.586 0.584 0.588 0.588 0.588Concentration : 1.49 grams in 100 C.C. of solution. Density= 1*008.Pressure ............ 734 828 935 1078 1215 1432Solubility ........ 0.586 0-579 0.577 0.581 0'585 0.586Concentration : 4.061 grams in 100 C.C. of solution. Density = 1-029.Pressure ............ 754 835 883 1093 1208 1358Solubility ......... 0.578 0.573 0.571 0574 0.579 0.5800 0 550 FINDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS ANDContrary to the behaviour of carbon dioxide, the solubility ofnitrous oxide is lowered by ferric hydroxide, the diminution of solu-bility being practically proportional to the concentration, as shownin Fig. 14. Further, the behaviour of nitrous oxide is unlike thatof carbon dioxide, in that there is no long period of slow absorptionobservable, neither at high nor at low pressures.FIG.9.750 850 950 1050 1150 1250 1350 1450Pressure in <mm. Eg.Nitrous oxide and dextrin (-).Nitrous oxide and ferric hydroxide (----).TABLE 14.-8olub&ty of Nitrous Oxide in Sohtions of Dextrin(see also Fig. 9).Concentration: 6.98 grams of dextrin in 100 C.C. of solution.Density = 1.018.Pressure ............ 739 822 949 1092 i239 1368Solubility ......... 0.549 0-550 0.555 0.560 0-562 0'569Concentration : 13.01 grams in 100 C.C. of solution. Density= 1.039.Pressure ............ 729 836 914 1023 I237 1358Solubility ......... 0.529 0.523 -- 0.526 0.533 0.540 0.544Concentration : 20.30 grams in 100 C.C.of solution. Density = 1.062.Pressure ............ 740 836 911 1149 1290 1360Solubility ......... 0.503 0'499 0.503 0.509 0'513 0-516Compare also Fig. 15FINE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 5510.54000.5200TABLE 15.-h'olubility of Nitrous Oxide in Solutions of ArseniousSulphide.Concentration: 1-85 grams of As,S3 in 100 C.C. of solution.Pressure ............ 746 820 924 1055 1196 1346Solubility ......... 0.591 0.590 0'590 0'592 0.593 0'593Density = 1.004.Concentration : 2-29 grams in 100 C.C. of solution. Density = 1.007.Pressure ............ 746 850 1006 1110 1209 1300Solubility ......... 0.590 0586 0'588 0.589 0.589 0.590From these figures it is seen that arsenious sulphide is withoutinfluence on the solubility of nitrous oxide.-"732FIG.10.750 850 950 1050 1150 1250 1350 1450Pressure in mm. Hg.Nitrous oxide and starch (-).Nitrous oxide and glycogen (- - -1,TABLE 16,--SoZub%ty of Nitrous Oxide in Sohtions of Starch(see also Fig. 10).Concentration: 2.50 grams of starch in 100 C.C. of solution.Density = 1.009.Pressure ............ 742 871 1020 1166 1284 1441Solubility ......... 0.580 0.576 0.575 0-578 0.581 0.582Pressure ........... 742 848 929 1046 1261 1381Solubility ........., 0.561 0.554 0.553 0554 0.562 0.567Concentration : 6.89 grams in 100 C.C. of solution. Density = 1.021.Concentration : 10.00 grams in 100 C.C. of solution. Density = 1.030.Pressure ..... . ...... 742 860 948 1071 1235 1350Solubility ......... 0.550 0.544 0.545 0-545 0.553 0.555Concentration : 13.73 grams in 100 C.C.of solution. Density = 1.040.Pressure ............ 739 836 982 1136 1252 1387Solubility ...... .. 0.557 0.532 0.530 0'535 0-536 0.53552 FINDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS ANDThe influence of concentration on the solubility is shown inFig. 15.TABLE 17.--SolubiEity of Nitrous Oxide in Solutions of Gelatin(see also Fig. 11).Concentration: 1.31 grams of gelatin in 100 C.C. of solution.Density = 0.999.Pressure ............ 731 849 937 1069 1176 1328Solubility ......... 0-589 0.590 0.590 0.592 0592 0'592Concentration : 3.09 grams in 100 C.C. of solution. Density = 1.003.Pressure ........... 730 858 950 1089 1230 1373Solubility ......... 0.581 0.582 0.584 0.586 0.588 0.588Concentration : 6.06 grams in 100 C.C.of solution. Density = 1.008.Pressure ............ 730 850 961 1097 1247 1379Solubility ......... 05$0 0-563 0'566 0-568 0'570 0.571The influence of concentration of gelatin on the solubility isshown in Fig. 14.FIG. 11.0*60005 5 0*5800rnb ru60.5600750 850 950 1050 1150 1250 1350 1450Pressure in mna. ZT9.Nitroits oxide and gelatin.TABLE 18.--Xolubility of Nitrous Oxide in Solutions of Glycogen(see Fig. 10).Concentration: 0.49 gram of glycogen in 100 C.C. of solution.Density = 0.999.Pressure ............ 738 889 977 110.2 1239 1386Solubility ......... 0.590 0.588 0.591 0'594 0.594 0-594Concentration: 1.00 gram of glycogen in 100 C.C. of solution.Density= 1.002.Pressure ............737 871 991 1050 1201 1360Soliihility ........ 0.585 0.584 0'589 0.591 0.594 0-596The influence of concentration of glycogen on the solubility ofnitrous oxide is shown in Fig. 14FINE SUSPENSIONS ON THE SOLUBlLITY OF GASES IN WATER. 553TABLE 19.--Solubility of Nitrous Oxide in, Solutions of Egg-Albumlen (see also Fig. 12).Concentration: 0.35 gram of albumen in 100 C.C. of solution.Density = 0.998.Pressure ............ 735 830 954 1139 1249 1363Solubility ......... 0.580 0.578 0.580 0.581 0.580 0.580Concentration : 0.75 gram in 100 C.C. of solution. Density = 1.000.Pressure ............ 735 820 872 951 1104 1344Solubility ......... 0.569 0.562 0-564 0'567 0573 0.577Pressure ............ 729 811 886 946 1199 1399Solubility ......... 0.548 0.535 0.540 0.544 0.553 0.558Concentration : 1.60 grams in 100 C.C. of solution.Density = 1.005.The influence of concentration on solubility is shown in Fig. 14.FIG. 12.750 850 950 1050 1150 1250 1360 1450Pressure in mm. Hg.Nitrous oxide and egg-albumen (-).NitTom oxide and serum-albumen (-- -).TABLE 2 0 . 4 o l u b i l i t y of Nitrous Oxide in Solutions of Sepum-A l b u m e n (see also Fig. 12).Concentration: 0.32 gram of serum-albumen in 100 C.C.Density = 0.998.Pressure ............ 746 873 978 1126 3.259 1395Soliibility ......... 0.583 0.581 0.579 0.586 0.588 0,591Concentration : 1-40 grams in 100 C.C. of solution. Density = 1.001Pressure ............ 743 842 913 1048 1228 1358Solubility .........0.537 0'538 0.545 0.550 0'558 0-562The influence of concentration on solubility is shown in Fig. 14554 FINDLAY AND CREIGH'I'ON : THE lNFLUENCE OF COLLOlDS ANDTABLE 21.--SoEubility of Nitrous Oxide in Solutions of Silicic Acid(see also Fig. 13).Concentration: 1.87 grams of SiO, in 100 C.C. of solution,Density = 1-001.Pressure ............ 748 825 921 1046 1217 1349Solubility ......... 0.596 0.598 0.598 O%OO 0.602 0'604Concentration : 3.63 gra.ms in 100 C.C. of solution.Pressure ............ 741 848 994 1122 1217 1394Solubility ......... 0'601 0'602 0.605 0.607 0-608 0'609Density= 1.005.The influence of concentration on the solubility is shown inFig. 14.O.iOO00'68000.6600A.4 .-0'6400 - m3t/l0'620Co '60000'580C7TABLE 22.--Solubility of Nitrous Oxide in Water containingCharcoal and Silica in Suspension (see also Fig.13).100 C.C. of liquid contained 0.227 gram of charcoal. Density= 1.000.Pressure ..._........ 729 824 936 1034 1150 1254 1356So!ubility ............ 0.596 0.600 0.618 0.635 0.648 0.661 0.674100 C.C. of liquid contained 0.30 gram of SiO,. Density=1'000.Pressure ............ 730 846 960 1081 1224 2365 1481Solubility ............ 0.592 0-593 0.595 0.597 0.597 0.600 0-60FlNE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 555111.-Solubility of Carbon Dioxide in Solutions of Aniline.In order that the solubility curves previously obtained mightbe compared directly with a case where chemical combination isknown to occur, the solubility of carbon dioxide in solutions ofaniline was determined.The results are contained in table 23.FIG. 14.Concentration in grams per 100 C.C. solution.TABLE 23.Concentration: 0.206 gram of aniline in 100 C.C. of solution.Pressure ............ 748 808 920 1053 1159 1243Solubility ......... 0.865 0.855 0-857 0.855 0'862 0'860Concentration: 0.425 gram in 100 C.C. of solution.Pressure ............ 760 816 921 1150 1236 1380Solubility ......... 0'909 0.897 0.897 0.897 0'902 0.908Concentration: 0.566 gram in 100 C.C. of solution.Pressure ............ 760 823 941 1082 1223 1341Solubility ......... 0.935 0.929 0.925 0.923 0-924 0.930Concentration: 0.743 gram in 100 C.C. of solution.Pressure ............ 760 895 983 1063 1223 1302Solubility .........0-953 0.941 0'940 0-940 0.940 0-942The solubility-pressure curves are similar in form to those forcarbon dioxide and ferric hydroxide (Fig. 1).IV.-Solubility of Carbon Dioxide in Solu,tions of PotassiumChloride.Although many investigators (see Steiner, AnnaZem, 1894, 52,275; Gordon, Zeitsch. phgsikal. Chem., 1895, 18, 1; Braun, dbid.556 FINDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS AND1900, 33, 721; Knopp, ibid., 1904, 48, 97; Hufner, ibid., 1907,57, 611) have studied the influence of dissolved substances, bothelectrolytes and non-electrolytes, on the solubility of gases, suchFrG. 15.-5 10-0 12-5 15.0 17.Concentration in gram per 100 C.C. solution.investigations have always been made at only one pressure. I norder that a comparison might be made between the influence ofcolloids and suspensions (emulsoids and suspensoids) and of truePressure in warn. Hg.Carbon dioxide and potassium chloride.solutions, the solubility of carbon dioxide in solutions of potassiumchloride at different pressures was determined. The results arecontained in table 24, and represented in Fig.16FINE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 557TABLE 24 (see also Fig. 16).Concentration: 7.45 grams of KCl in 100 C.C. of solution.Density = 1.043.Pressure ............ 756 850 953 1116 1249 1362Solubility ........ 0.694 0-693 0.688 0-700 0.709 0.710Concentration: 5.00 grams of KCl in 100 C.C. Density=1*031.Pressure ............ 756 832 901 1050 1150 1223Solubility .........0.731 0-727 0'724 0.726 0.735 0.736Concentration: 2-56 grams of KCI in 100 C.C. Density=1*016.Pressure ........... 756 852 981 1079 1190 1362Solubility ......... 0.767 0'761 0.761 0'762 0.768 0.766Discussion of Results.A glance a t the curves given on the preceding pages will showthat many peculiarities of behaviour are found in the solubilityof gases in liquids when that solubility is investigated, not, aspreviously, at only one pressure, but a t different pressures. Sovaried, indeed, is the influence, not only in degree, but in kind,of the different solutes or pseudo-solutes and suspensions on thesolubility of carbon dioxide and nitrous oxide, that conclusionsdrawn from the behaviour under one pressure might be veryerroneous when considered for another pressure.The substances the influence of which on the solubility of thetwo gases, carbon dioxide and nitrous oxide, has been studied,may be divided into emulsoids and suspensoids.To the formerclass belong ferric hydroxide, gelatin, starch, glycogen, egg-albumen, serum-albumen, and silicic acid; to the latter clam,arsenious sulphide, charcoal, and silica. Dextrin may, perhaps, beregarded as intermediate between a true solute and an emulsoid.Aniline and potassium chloride have been included merely for thepurposes of comparison.In the case of the emulsoids, we see that under atmosphericpressure, silicic acid increases the solubility both of carbon dioxideand of nitrous oxide; ferric hydroxide and gelatin increase thesolubility of carbon dioxide but diminish the solubility of nitrousoxide; and the other emulsoids decrease the solubility of both thegasea Of the suspensoids, arsenious sulphide is practically withoutinfluence on the solubility of either gas, while charcoal and silicaincrease the solubility of both gases.Lastly, dextrin decreasesthe solubility of both carbon dioxide and of nitrous oxide.What the nature of the interaction may be in the case ofgelatin and carbon dioxide is not, perhaps, quite easily decided558 FLNDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS ANDGelatin, as is known, is an amphoteric substance, and may thereforefunction as a weak base. It seems to us, however, tu be doubtfulif this basic property is sufficient in itself to explain t,he wholeincrease in the solubility.Possibly some more complicated actionoccurs, an indication of which appears to be given by the effectof carbon dioxide in lowering the gelatinisation point of gelatinsolutions already referred to (p. 544).I n the case of ferric hydroxide, as has already been pointed outby Luther and Krsnjavi (Zeitsch. physikaZ. Chem., 1905, 46, 170),there is probably complex ion formation. The formation of aferric carbonate appears from the work of Raikow (Chem. Zeit.,1907, 31, 87) and of Cameron and Robinson (J. Physical Chem.,1908, 12, 561) to be excluded.Although in these cases we may regard chemical combination asbeing one of the causes, perhaps the main cause, of the increasedsolubility of carbon dioxide, it is difficult to adopt a similarexplanation in the case of silicic acid, which increases the solubilityboth of carbon dioxide and of nit-rous oxide.In the latter casean explanation is more probably to be sought in the phenomena ofadsorption (see also p. 560).Solubility Referred to the Water in the- Solutions.-With regardto the lowering effect of electrolytes and non-electrolytes on thesolubility of gases in water, the view has been expressed, moreespecially by J. C. Philip (Trans., 1907, 91, 711), that the observeddepression wn be explained on the assumptions: (1) that onlythe water in the solution acts as solvent for the gas, and that thissolvent power is not affected by the presence of the solute; (2) thatthe solute molecules are more or less hydrated, and thereforediminish the amount of active solvent for the gas; (3) that thegas does not dissolve in the solute, whether anhydrous or hydrated.It must be borne in mind that the cases investigated by us arenot generally comparable with those to which Philip applied histheory, for with the exceptions of the solutions of potassiumchloride, and, possibly, dextrin, the solvent systems were not homo-geneous, but must be regarded, most probably, as heterogeneous.And that alters the case entirely.With regard to the solutions of potassium chloride, it may bementioned that the values calculated for the degree of hydrationvary from 6.42 to 8.68 molecules of water to one molecule of salt.These numbers are rather lower than those calculated by Philip,but not greatly so.In the cas0 of dextrin, however, it is evident that the solutionsof dextrin show considerably different behaviour, according asthe solubility of carbon dioxide or of nitrous oxide is investigatedFINE SUSPENSIONS ON THE SOLTJBILITY OF GASES IN WATER.559In the former case practically no hydration is evidenced; in thelatter case a slight amount of hydration would be calculated. Butin the case of carbon dioxide it will be seen that the numbersrepresenting the solubility referred to water in the solutiondiminish with increase of concentration, whereas in the case ofnitrous oxide, the numbers increase.It does not appear to us that sufficient evidence has yet beenadduced in support of the theory put forward by Philip.More-over, we believe that the solubility curves which we have obtaineda t higher pressures show the necessity of extending the range ofinvestigation in this direction. On this we are at presentengaged. *Change of Solubility with Pressure.-Whatever conclusions maybe drawn as regards the influence of the suspensoids and emulsoidson the solubility of carbon dioxide and nitrous oxide from deter-minations at one pressure, they must to a greater or lesser degree befound inaccurate when applied over a range of pressures; for asthe figures previously given show, the solubility is not independentof the pressure (as it is in the case of pure water), nor are thesolubility curves for solutions of different concentration in all casesparallel.Assuming that the influence of ferric hydroxide and of gelatinis mainly due to chemical combination with formation of alargely hydrolysed compound, we should expect that thesolubility-pressure curve would first fall, owing to hydrolysis,and then remain nearly horizontal, owing to the diminution ofhydrolysis by addition of carbonic acid.This is the type of curveobtained with aniline and ferric hydroxide, but is better seen inthe case of the more weakly basic substance gelatin. Looked a tin this way, the curve for carbon dioxide and silicic acid wouldalso indicate chemical combination, and we should therefore haveto assume that silicic acid is amphoteric (for which we do notknow of any other evidence), or that between silicic acid andcarbonic acid a reaction takes place comparable with that betweensilicic acid and hydrofluoric acid, the compound formed beinghighly hydrolysed.As regards the influence of suspensions of charcoal and silica onthe solubility of carbon dioxide and nitrous oxide, and of silicicacid on the solubility of nitrous oxide, it will be noticed that weare here dealing with curves similar to those obtained by otherinvestigators for the absorption of gases or of dissolved substancesby charcoal.* Since this was written, a paper has appeared (this vol., p.66) by F. L. Usher,who fails t o find confirmation of the theory put forward by Philip560 FINDLAY AND CREIGHTON : THE INFLUENCE OF COLLOIDS ANDSimilarity is also shown by the fact that when one examines therelation between the concentration of gas in the water and in thesolid, the general relationship cg/cl = const., found by previousworkers for “ adsorption ” phenomena, also holds in the presentcases.Here c2 is the weight of gas taken up by the water in100 C.C. of the suspension, and c1 the weight taken up by thesuspended solid. x we have found to be equal to 4.TABLE 25.Charcoal and Carbon Dioxide,0.236 gram of Charcoal in 100 c.c.Charcoal and Nitrous Oxide,0.227 gram of Charcoal in 100 C.C.Pressure. c,. C,. C y C I .950 0’0086 0-1837 0.1321000 0.0127 0’1934 0.1101050 0.0178 0’2030 0.0991150 0.0266 0-2224 0.0921250 0’0365 0‘2417 0.0981350 0.0430 0.2610 0.108Pressure. cl. %* c&950 0-0059 0.1332 0.0531000 0.0085 0.1402 0.0481050 0-0109 0.1472 0.0431150 0.0151 0-1613 0.0451250 0.0200 0.1753 0-0471350 0.0259 0’1893 0.050In the above cases, therefore, increased solubility would beascribed to “ adsorption,” accompanied or unaccompanied byabsorption.The solubility curves so far discussed are comparatively simplein form, and the influence of the colloid or suspension may plausiblybe explained on the basis of partial chemical combination or of‘ I adsorption,” accompanied or unaccompanied by absorption.Inthese cases the solubility of the gases is increased a t all pressures.In most of the cases examined, however, where dealing withemulsoids, the solubility of the gas is diminished even when onetakes into account the volume of water in the solution. This maybe explained, formally, by the assumption of hydrate formation.But even if this be accepted, the remarkable behaviour observedat higher pressures remains to be accounted for.An examinationof the solubility-pressure curves shows that, with the exception ofthe cases already discussed, there exists for a number of thecolloids a very well-defined minimum of solubility, this minimumbeing more marked in concentrated than in dilute solutions. I nall such cases t h influence of the colloid must be a very complexone, and two effects a t least must enter into play, one causing adiminution of solubility with pressure, the other an increase. Indilute solutions the former is sometimes absent or negligible.So far as the rising portion of thecurves is concerned, we assume that the rise is due t o “ adsorption,”whatever the true nature of this process may be. For this portionof the different curves we have also found that the ratioci/cl = const., as is shown by the following table:What are these two factorsFINE SUSPENSIONS ON THE SOLUBILITY OF GASES IN WATER. 561TABLE 26.Ses.umAZbwnen and Nitrous Oxide.1-40 grams of albumen per 100 C.C.915 0.0017 0'1164 0.1081000 0*0026 OC1272 0~1001050 0*0031 0.1336 0-1031150 0.0047 0.1463 0.0981250 0*0061 0.1590 0.1051350 0.0079 0.1717 0.1110.537 is the valnc of the solubility used for calculating c2.Pressure. el - c,. c;/cl.A similar degree of constancy is obtained in the case of theother curves.As regards the factor producing the lowering of the solubility,we believe that the simplest assumption to make is that ofsolubility of the gas in the colloid phase. As has already beenpointed out, we are dealing here with heterogeneous systems,comparable with a mixture of two partly miscible liquids. So faras we are aware, the solubility of a gas in such a system has notyet been investigated; but we may very properly assume that thegas dissolves (unequally) in the two phases, namely, in the casesunder discussion, in the aqueous phase and the colloid phase. Wemust also further assume that the solubility in the colloid phaseno longer follows Henry's law, but that the solubility increasesless rapidly than the pressure. Under such conditions the solubilitycurve would no longer be a straight line, but would fall withincrease of pressure. Such a deviation from Henry's law signifiesthat the molecular weight of the gas in the gaseous phase and inthe colloid phase is no lodger the same; and we must thereforeassume that the gases have a higher molecular weight in the colloidphase than in the water phase. That is, we must assume poly-merisation of the gas in the colloid phase. By these assumptionswe are enabled to explain, formally a t least, the behaviourobserved, and it must be left to future investigation to showwhether the explanation is only formal or may be regarded asessential. It is clear, however, from the foregoing investigationthat colloids in solution will not necessarily increase the solubilityof a gas. The action is a specific one, and depends both on thecolloid and on the gas.CHEMICAL DEPARTMENT.UNIVERSITY OF BIRMINGHAM

ISSN:0368-1645    

DOI:10.1039/CT9109700536

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

562 SMITH AND WATTS: ABSORPTION SPECTRA ANDLVIII.-Absolption Spectra aizd Meltirig-point Curves ofA?*onzatic Biuxoamines.By CLARENCE SMITH and CONSTANCE HAMILTON WATTS.THE discovery by Griess that the same diazoamine is formed bydiazotising either of two primary aromatic amines and coupling theproduct with the other, led twenty or thirty years ago to numerousinvestigations which had for their object the determination of theconstitution of such mixed diazoamines and the isolation of thetwo possible isomeric forms, ArN2*NHAr/ and ArNH*N2Ar’. Thelatter purpose has never been satisfactorily realised, whilst theformer has resulted in a mass of such conflicting evidence that evenat the present time the constitution of the aromatic diazoaminesremains an open question.In order to show that the conclusions at which we have arrivedare supported by the bulk of this earlier evidence, it is necessaryto recapitulate the main points made by previous investigators, themore so as an impartial survey of all the facts appears to havebeen omitted hitherto.An examination of the substances obtained by decomposing withwater the product of the action of carbonyl chloride on a benzenesolution of a diazoamine led Sarauw to the conclusion that theimino-group is attached to the more negative aromatic nucleus, andthat the initial product (not isolated) of the reaction is a diazo-carbamide, ArN2*NAr/GO*NAr/*N2Ar, in which Ar is the lessnegative benzenoid group.A perusal of the author’s two papers(Ber.,1881, 14, 2442; 1882, 15, 42) proves, however, that hisevidence is inconclusive, for whilst phenol and dibromocarbanilideare the products arising from the decomposition by water of thediazocarbamide obtained from benzenediazoamino-p-bromobenzene,the action of water on the diazocarbamide from benzenediazoamino-p-toluene yields both phenol and pcresol and a viscous productfrom which only di-p-tolylcarbamide can be isolated.The viscousproduct may and probably does contain diphenylcarbamide, seeingthat both phenol and p-cresol are formed. If such is the case, thediazoamine reacts with carbonyl chloride in accordance with bothformulze, C6H5-N2-NH*C7H7 and C6H5*NH*N2*C7H,. Similarreasoning holds in the case of benzenediazo-m-aminobenzoic acid,phenol and m-hydroxybenzoic acid being the only substancesisolated from the decomposition products of its diazocarbamide.The preceding constitution of a mixed diazoamine has been farmore satisfactorily established by Goldschmidt and Molinari (Ber.MELTING-POINT CURVES OF AROMATIC DIAZOAMINES.5631888, 2 1, 25 78), by heating equimolecular quantities of the diazo-amine and phenylcarbimide in an indifferent solvent, such asbenzene. The product is a diazocarbamide, which can be isolatedand appears to be an individual substance; it is decomposed bywater, yielding a phenol, nitrogen, and a diarylcarbamide, of wliichone aromatic group is always pheny€, and the other the morenegative group of the original diazoamine :Ar*N3H*Ar‘ + C,H,*NCO 4 C,H,*NH*CO*NAr’*N2Ar +C,H5*NH*CO*NHAr’ + N, + Ar-OH.In the preceding year, however, the results of two investigationswere published which partly supported and partly opposedGoldschmidt’s conclusions.Heumann and Oeconomides (Ber., 1887,20, 372, 904) found that diazoaminobenzene, when heated inphenol, reacted to form aniline and benzeneazophenol ; similarly,p-chlorobenzenediazoamino-p-toluene gave p-chloroaniline andp-tolueneazophenol. Benzenediazoamino-p-toluene, however, withphenol or resorcinol gave approximately equal quantities of anilineand p-toluidine and a mixture of hydroxyazc-compounds. I n thesereactions, therefore, some mixed diazoamines behave as if con-stituted in accordance with Goldschmidt’s formula, others likemixtures of equal quantities of ArN,*NHAr’ and ArNH*N,Ar’.Still more striking is the evidence advanced by Noelting and Binder( B e y ., 1887, 20, 3004), who submitted benzenediazoamino-ptolueneand other mixed diazoamines to the attack of numerous reagents,and fonnd that they behaved sometimes in accordance with theformula ArN2*NHAr’, sometimes in accordance with the formulaAr*NH*N,Ar’, but generally as a mixture of both forms.As a result of these and other investigations, two views werecurrent regarding the constitution of mixed aromatic diazoamines,and these have not been materially modified by more recentresearches. One view, which does not appear to have been urgentlyadvanced by any single investigator, regards the mixed diazoaminesas consisting of the two possible isomerides, ArN,*NHAr’ andArNH*N2Ar’. The other theory, initiated by Goldschmidt, regardsthe diazoamines as being constituted so that the imino-group isattached to the more negative aromatic group.Reactions in whichthe diazoamine yields four products of decomposition are attributedto a migration of the iminic hydrogen atom due to the presence ofwater, alcohol, or an electrolyte, and are explained by an initialaddition of water or the like; thus:Ar*N:N*NHAr‘+ HX -+ Ar*NH*NX*NHAr’ ;by the elimination of HX, Ar*NH*N,Ar’ and ArN,*NHAr’ mayresult, and by subsequent decomposition yield each a pair ofproducts. Goldschmidt claimed that the migration of the iminicVOL. XCVII P 564 SMITH AND WATTS: ABSORPTION SPECTRA ANDhydrogen atom does not occur in indifferent solvents, such asbenzene, petroleum, or chloroform, and consequently in such solventsdiazoamines behave as individual substances and not its mixtures,and to this cause attributes the success of his phenylcarbimidemethod of determining the constitution of diazoamines.I n arriving at this theory, Goldschmidt apparently has over-looked the exhaustive researches in 1886-1895 of Meldola andStreatfeild on alkylated diazoamines.Although alkylation m amethod of determining constitution has been viewed in recent yearswith some suspicion, yet in some instances, for example, thephthaleins and the hydroxyazo-compounds, the problem of theconstitution of a substance containing a mobile hydrogen atomhas been approached and to a great extent solved by replacing themigratory hydrogen atom by an immobile alkyl group.I f , there-fore, an alkylated diazoamine can be shown to have a similarconstitution to that of its parent substance, Meldola and Streatfeild’sresearches acquire a new and fundamental significance, and can beutilised directly to prove the untenability of the theory that in a,mixed aromatic diazoamine the imino-group is attached t o the morenegative aromatic nucleus. We have been able to prove the pointin question by means of the spectrograph. Meldola and Streatfeildshowed that three isomeric mp’-dinitrodiazoethylaminobenzenesexist, namely :I. 772-Nitrobenzenediazoethylamino-p-nitroberizene,NO,prepared from diazotised mnitroaniline and p-nitroethylaniline.11.p-Nitrobenzenediazoethylamino-m-nitrobenzene,from diazotised p-nitroaniline and mmitroethylaniline.111. mp’-Dinitrodiazoethylaminobenzene,r;r 0,obtained by the direct ethylation of mpr-dinitrodiazoaminobenzene.Isomeride I11 gives an absorption curve different from those ofI and 11, and absolutely identical with that of its parent diazo-amine, which is thus proved to have a constitution similar to thatof isomeride 111. The constitution of this isomeride has been prac-tically proved by Meldola and Streatfeild, who find that it can bMELTING-POINT CURVES OF AROMATIC DIAZOAMINES. 565synthesised by heating equimolecular quantities of isomerides I andI1 in alcohol or benzene. Meldola and Streatfeild regard I11 as aco’mpound of I and 11.For reasons given below we believe it tobe an equimolecular mixture of I and 11, but for the present purposethis difference of opinion is immaterial, the main point being thatI11 is composed of equal quantities of I and 11, either mixed orcombined. Now, in the diazoamine under discussion, the p-nitro-benzene nucleus is probably the more negative, but whether thisis really so does not affect the argument. Assuming that it is,the diazoamine will be represented by the Goldschmidt theory bythe formula:and the directly alkylated derivative, which must possess a similarconstitution to that of its parent substance from the spectrometricevidence, will have the formula:No2that is, should be identical with isomeride I above. Since experi-ment shows that the directly alkylated derivative is I11 above, thatis, a mixture of equal quantities of I and 11, it follows that thepremise is incorrect, and that mp’-dinitrodiazoaminobenzene con-sists of a mixture (or compound) of equal quantities of the twoindividually unknown isomerides :Of course, the acceptance of this theory at once renders intelligiblethe numerous reactions in which a mixed diazoamine yields fourproducts of decomposition. It only remains t o explain why thediazoamine a t times yields only two products, decomposing asthough it consisted entirely of one of the two unknown isomerides.A t present it is impossible to advance any argument satisfactorilysupported by experimental evidence.The most obvious explanationis the selective attack of the reagent.If one of the two isomeridesis attacked a t a much greater rate than the other, a transformationof the less susceptible into the more susceptible isomeride mustoccur in order to preserve the equilibrium ratio a t unity, and thediazoamine will decompose almost entirely as though it consistedof one isomeride only. The most important case to which thisexplanation can be applied is the phenylcarbimide reaction, sinceP P 566 SMITH AND WATTS: ABSORPTION SPECTRA ANDthis forms the main foundation of the Goldschmidt theory of theconstitution of diazoamines. Goldschmidt attributes the formationof an individual diazocarbamide from phenylcarbimide and a mixeddiazoamine in benzene solution to the immobility of the iminichydrogen atom in an indifferent solvent.Dimroth, however, givesinstances (Annuten, 1904, 335, 1) in which the transformation ofone tautomeride into another by the migration of a mobile hydrogenatom proceeds much more rapidly in an indifferent solvent than ina hydroxylic solvent. Goldschmidt admits that this is correct inprinciple, but is not applicable to the particular case of the diazo-amines, because one of the isomeric forms is unknown (Ber., 1905,38, 1097). Our experiments prove, however, that both forms existas an inseparable mixture in the mixed diazoamine. The unitarycourse of the phenylcarbimide reaction, therefore, may very wellbe due to the selective attack of the reagent, the transformationof one isomeride in the mixed diazoamine into the more susceptibleform being facilitated by the indifferent solvent to such a degreethat one diazocarbamide is produced only in inappreciablequantities.It would be premature to dogmatise from the result of theexamination of a single triplet of ethers originating from a diazo-amine containing aryl groups of not very different character, andwe do not unhesitatingly commit ourselves at present to the viewsadvanced above, and the less so in consequence of Pechmann’s workon amidines of the type ArN:CPh*NH*Ar’ (Ber., 1895, 28, 869),which differ from mixed diazoamines by containing the group CPhin place of a nitrogen atom.The compound C,H5*N:CPh=NH*CpH7,obtained from benzanilide iminochloride and p-toluidine, is identicalwith C,H,-N:CPh-NH*C,H,, prepared from benzoyl-p-toluidideiminochloride and aniline, but yields by ethylation a mixture of twoethyl derivatives corresponding with the two formuk given. WhenAr and Art are different in character, however, the amidines pro-duced by the two methods are still identical, but yield only oneether, indicating an immobility of the hydrogen atom in theamidine.A similar constitution may obtain for mixed diazoaminescontaining aryl groups of very different character, the imino-groupremaining attached to the negative nucleus as in the Goldschmidttheory. This view of the constitution of such diazoamines, which,of course, harmonises well with the chemical behaviour cited above,can be tested spectrometrically, and is receiving our attention.The derivative obtained by the direct alkylation of a mixeddiazoamine has been shown by Meldola and Streatfeild to becomposed of equal quantities of the two isomerides, ArN,*NR*Arfand ArNR*N2*Ar’, by boiling an alcoholic or benzene solution oMELTING-POINT CURVES OF.AROMATIC DIAZOAMINES. 567these isomerides for one hour, whereby a product is obtainedidentical with the directly alkylated diazoamine. The authorsregard this product as a compound of the two isomerides, althoughthey found that the molecular weight in benzene by the cryoscopicmethod agreed with a unimolecular and not a bimolecular formula,a discrepancy which they attribute to dissociation of the compoundin the benzene solution. This explanation is untenable, since thecompound is produced in boiling benzene, and it is very improbablethat it would dissociate in the cold solvent. Mr.T. J. Mander,to whom we proffer our thanks, has determined the molecularweights of several alkylated mixed diazoamines in boiling alcoholand benzene, and has obtained values which are always less thanthose corresponding with the unimolecular formula. The com-pound, therefore, does not exist in the solution, and must beproduced, if formed a t all, at the instant of the deposition of thesolid from the solution. To ascertain whether or not a compoundis formed, we have determined the melting-point curve of mixturesof pnitrobenzenediazoethylamino-mnitrobenzene and m-nitro-benzenediazoethylamino-p-nitrobenzene. The curve is of the simpleU-sbape characteristic of mixtures, and has its minimum at it pointcorresponding with the mixture of equal quantities of the twoisomerides and a temperature identical with the melting point ofthe substance obtained by the direct ethylation of mp‘-dinitrodiazo-aminobenzene. This evidence, combined with that furnished bythe cryoscopic and the ebullioscopic methods of determining themolecular weight, proves that the directly ethylated substance is asolid solution of equal quantities of the two isomerides mentionedabove.EXPERIMENTAL.mp’-Dinitrodiazoarninob enzene.-This compound was prepared inthe usual way from mnitroaniline and p-nitrobenzenediazoniumchloride in the presence of sodium acetate.The crude substancemelted at 214O; after crystallisation from a mixture of equalvolumes of alcohol and toluene, the melting point wils 218-219O.Since Meldola and Streatfeild give the melting point as 212-212-5O(Trans., 1859, 55, 416), the substance waa again dissolved in boilingalcohol and toluene, filtered while still hot (precipitate A), againwhen cold (precipitate B), and yet again after concentrating themother liquor (precipitate C).The melting points of A, B, Crespectively were 220°, 212.b-213°, 219-220O. After re-crystallisation from the same solvent, the melting points were231-232O, 231-232O, 230-231°, in a bath previously heated to180O. After a third recrystallisation, the melting points were231-232O, 231--232O, 228O. In all cases the substance decompose568 SMITH AND WATTS: ABSORPTION SPECTRA ANDat the melting point.The three samples all gave the same orange-red colour in alcoholic sodium hydroxide, and dissolved withoutchange of colour in concentrated sulphuric acid, forming solutionswhich ultimately became colourless. The melting point ofpp/-dinitrodiazoaminobenzene is given by Hantzsch as 2 3 3 O(decomp.), a value which we have confirmed. The melting point ofa mixture of approximately equal quantities of this compound andour mp/-isomeride melted a t 208-21 lo (decomp.).mpf-Dinitrodiazoethylanzinobenzene was prepared by heating thediazoamine with alcoholic potassium hydroxide and ethyl iodide onthe water-bath for eight hours, and twice recrystallising the productfrom alcohol. It melted at 152--153O, dissolved in alcoholic sodiumhydroxide without change of colour, and gave a solution in con-centrated sulphuric acid, which became colourless after a few hours.and p-nitro-B enzenediazoethylamino-m-nitrob enzcne were prepared from diazo-tised mnitroaniline and p-nitroethylaniline and diazotised p-nitro-aniline and m-nitroethylaniline respectively, and were recrystallisedfrom alcohol and toluene until the melting points were constantat 174-5-174.8O and 188*5--188*7O respectively ; the substancesdissolved in alcoholic sodium hydroxide without change of colour,and gave solutions in concentrated sulphuric acid, which ultimatelybecame colourless.The absorption curves of mp’-dinitrodiazoaminobenzene and ofthe three ethylated isomerides are shown in Fig.1.The curves ofthe parent diazoamine and of its directly ethylated derivative areidentical throughout. The curves of the other two isomerides,although naturally very similar to, are quite distinct from, that ofthe directly ethylated isomeride. A comparison of the three curves,particularly in the neighbourhood of oscillation frequencies 3200 to3600, indicates that the curve of the directly ethylated diazoamineis very much what would be expected if the substance is a mixtureof the other two isomerides. The most important result, however,is the proof of the similarity of the constitutions of mp’-dinitro-diazoaminobenzene and its directly ethylated derivative.To obtain the melting-point curve of m-nitrobenzenediazoethyl-amino-p-nitrobenzene and p-nitrobenzenediazoethylamino-m-nitro-benzene shown in Fig.2, it is necessary that the heating of thedifferent mixtures shall be as uniform and under as nearly thesame conditions as possible, for it is well known that the apparentmelting point of a diazoamine can be raised many degrees by rapidheating. Intimate mixtures of the two isomerides were obtainedby making two solutions in benzene distilled over sodium:m-iVitro b enzenediaao et h ylamino-p-nitro b enz enMELTING-POINT CURVES OF AROMATIC DIAZOAMINES. 569A. Containing 0-1575 gram of m-nitrobenzenediazoethylamino-p-nitrobenzene in 250 C.C.B. Containing 0.1575 gram of p-nitrobenzenediazoethylamino-m-nitrobenzene in 250 C.C.Mixtures of different volumes of these two solutions wereevaporated on the water-bath, the residue was detached from thebasin, finely powdered, and transferred as completely as possible tocapillary tubes about 2 mm.in diameter and about 15 cm. long.FIG. 1.Oscillation frequencies.22 24 26 28 3000 32 34 36 30 4000 42 44 46mp'-Di?~~t.iodinxoami~~enzene and its ethyl derivative..___..__._..__..._-._.__._ m- Nitrobenzenediaaoeth y lamino- p-nitrobenzne.____-.- p - Nitrobenmwdiuzoeth y lamino- m- nit robenzene .These tubes were attached to a thermometer 70 cm. in length, havinga range from looo to 200°, graduated in tenths of a degree. Thebulb of the thermometer was immersed in sulphuric acid containedin the outer jacket of a Victor Meyer vapour density apparatusThe temperature of the acid was raised to looQ, then the capillarytube was affixed to the thermometer, and the temperature was raisedfairly rapidly to within loo of the melting point of the precedingmixture; the rate of heating was then adjusted so that the tem-perature rose lo per minute570 SMITH AND WATTS : AROMATIC DIAZOAMINES.CorrcctcdC.C. of A.C.C. of B. melting point.20 0 178'5-1 78.8"19 1 176.618 2 169.1-169*817 3 166.9-167.216 4 164.5-165.415 5 159.6-160.414 6 157.3-157'513 7 156.1-156.511 9 156 '3-156'910 10 155 -4-1 56 -212 a 156.4-156.9CorrectedC.C. of A . C.C. of B. melting point.9 11 157'2"8 12 160 '2 -1 61 -67 13 164 *5-16556 14 166 '8-167 '45 15 169.1-169'84 16 176.1-176.93 17 177.6-177'92 18 185.9-186 '10 20 193.2-1 93.41 19 ia6.9-ia7-2FIG. 2.~ O O A 90 ao 70 60 50 40 30 20 10 ox,0 10 20 30 40 50 60 70 80 90 lOOBAA = m- Nitrobenzencdiazoeth ylamino- p-nitrobenzene.B = p-Nitrobenzeiaediazoethylamino-m -nitrobenzeene.It will be noticed that mixtures containing from 65 to 50 percent. of A melt at only slightly different temperatures, but therABSORPTION SPECTRA AND CHEMICAL CONSTITUTION. 571is not the slightest doubt that the equimolecular 50 per cent.mixture has the lowest melting point, which is the same as that ofthe substance obtained by the ethylation of mp'-dinitrodiazoamino-benzene.In order to see whether a compound of the two isowerides isformed under the conditions mentioned by Meldola and Streatfeild,mixtures of A and B were heated under a reflux condenser forone hour on the water-bath; the benzene was then evaporated, andthe melting points of the residues determined as above. Theresults tabulated below show that the melting points are practicallyunchanged by this treatment:CorrectedC.C. of A. C.C. of B. melting point.20 0 178.2-178 '3"15 5 159.3-159'712 8 156.3-156.810 10 155.1-155*7Correctedmelting point. C.C. of A. C.C. of B.8 12 160'4.-160 '9"5 15 168'8-169'80 20 192'0-192.6I n conclusion, we wish to express our thanks to the ResearchFund Committee of the Chemical Society for a grant by which theexpense of this investigation has been largely defrayed.EAST LONDON COLLEGE

ISSN:0368-1645    

DOI:10.1039/CT9109700562

出版商:RSC    

年代:1910

数据来源: RSC