摘要:

2738 EWINS: THE ALKALOIDS OF QUEBRACHO BARK. PART I.CCLV.-The All~aloids of Quebracho Bark. Palst I.The Constitution of Aspidospewnine.By ARTHUR JAMES EWINS.ASPIDOSPERMINE, C,H,O,N,, is the most readily obtained of thealkaloids of quebracho bark. It was first isolated by Fraude (Ber.,1878, 11, 2189) from the bark of Aspidosperma Quebracho, the" quebracho hlanco " of the Argentine, where it a t one time foundemployment in the treatment of fever. A further investigation oEWINS: THE ALKALOIDS OF QUEBRACHO BARK. PART I. 2739the alkaloids of this bark was carried out by Hesse (Annulen, 1882,211, 2491, who claimed to have isolated no less than six different,but closely related bases. Of these, however, only two, namely,aspidospesmine and quebrachine, may be said to have been wellcharacterised, and of these the latter has recently been shown tobe identical with yohimbine (Fourneau and Page, Bull.Sci.Pharmacol., 1914, 21, 7).* According to Hesse, quebrachine onlyoccurs in some specimens of the bark, and in those examined by thepresent author, at most only traces of this alkaloid have beenfound. The present paper is concerned mainly with some resultsobtained in experiments on the constitution of aspidospermine. Atthe same time the author has not so far been able t o confirm theexistence of the various bases described by Hesse with the exceptionof aspidospermine and qtiebrachine. Further, Hesse employedwarm dilute sulphuric acid €or the extraction of the alkaloids fromthe bark, and under these conditions, as is shown by the experi-ments recorded in this paper, aspidospermine is hydrolysed, givingrise to a new base, the properties of which make i t appear possiblethat the bases aspidosamine and hypoquebrachine described byHesse may have been impure forms of this decomposition productof aspidospermine.It may be mentioned, however, that in the course of the presentwork two new well-defined crystalline alkaloids were obtained insmall quantity. One, characterised by its sparing solubility inchloroform and by its failure to give colour reactions with oxidisingagents, crystallised from ethyl acetate in well-formed octahedramelting a t 176-177O.The other is very sparingly soluble inether, and crystallised from light petroleum in stout prisms meltinga t 149-150°.The latter base gives colour reactions whichresemble those given by the base obtained by the hydrolysis ofaspidospermine, but are less intense. It is hoped that these basesmay form the subject of a future investigation.Aspidospsrmine is a feeble base, which does not yield crystalline* By fractional precipitation of a portion of the crude alkaloid as tartrate asmall quantity of a crystalline salt was obtaincd from which a crystalline basemelting a t 225-226" was isolated. This base corresponded in general with thatdescribed by Hesse as quebrachine, and the recent statement by Fourneau and Page(Zoc. cit.), that the latter base is identical with yohimbine, was confirmed by thefollowing observations. A specimen of yohimbine (for which I am indebted toDr.G. Barger) melted a t 226", and a mixture of equal parts of the two bases melteda t the same temperature. Both bases melt to a red liquid and sublime a t200-210"/5 or 6 mm., forming clusters of prismatic needles. Further, Barger andMiss Field have found (private communication) that yohimbine gives a character-istic aulphonic acid derivative. The formation of this acid from the base(quebrachine) mentioned above was carried out, and its identity with that obtainedfrom yohimbine readily established2740 EWINS: THE ALKALOIDS OF QUERRACHO BARK. PART I.salts. It' does not react with methyl iodideexcept after prolonged heating a t 100°, and then yields a mixtureof products which have not yet been investigated.Aspidosperminecontains one methoxyl group, and does not' contain an AT-methylgroup, but has an acetyl group attached t o one nitrogen atom.This is shown by the following facts.The hydriodic acid solution obtained after treating aspidosper-mine according t o Zeisel's method yielded a new base, aspido-s i m , C,,H,,ON,. This base therefore differed in composition fromaspidospermine by the complex C,H,O, of which the hydrolysis ofone methoxyl group accounts for CH,. The residual C,H,O pointedt o the presence, in aspidospermine, of an acetyl group, which,from the constitutbn of the base, must be attached to a nitrogenatom. The presence of an acetyl group was confirmed by thefollowing results.Aspidospermine on hydrolysis with boiling dilute hydrochloricacid gives a new crystalline base, deacetylaspidbspermi,ae,C,,H,,ON,, which is readily reconverted into aspidospermine onacetylation.The new base on boiling with concentrated hydriodicacid (D 1.7) as would be expected yields aspidosine, the relation-ship of these' bases being shown as follows:Aspidospermine, C22H300JST2It is Izvorotatory.BoilingHI (1.7)Deace t y laspidospermine, C,H,,0N2 --+A s pi dosine, C l&&N2Nitronitrosodeacetylaspidospermine, C20H,,0,N,.Deacetylaspidospermine forms a characteristic, sparingly soluble,crystalline dihgdriodide ; the corresponding hydrochloride andhydrobromide are very readily soluble, and have not been obtainedcrystalline. It combines with methyl iodide, forming a crystallinederivative having the1 composition C,,H2,0N,,2CH,I. It yields amonoacetyl derivative (aspidospermine) and a crystalline mono-benzoyl derivative.It reacts with nitrous acid, and under suitableconditions yields a crystalline derivative, which appears t o be anitronitroso-compound. Deacetylaspidospermine thus appears to bea secondary tertiary base. The formation of a nitronitroso-derivEWINS: THE ALKALOIDS OF QUEBRACHO BARK. PART I. 2741ative, together with the colour reactions of the base, probablyindicate the presence in the molecule of a reduced quinolinenucleus. On boiling with hydriodic acid, nitronitrosodeacetyl-aspidospermine yields aspidosine. Deacetylaspidospermine isoptically active, but of opposite sign (dextrorotatory) to that ofaspidospermine.9 spw3osine is a crystalline lzvorotatory base, which, like deacetyl-aspidospermine, gives a characteristic, sparingly soluble, crystallineIiydriodide of the composition C,,H,,ON,,HI. It is less basic thandeaeetylaspidospermine, probably owing to the presence of aphenolic hydroxyl group.Probably also for this reason the baseis somewhat unstable in solution.On oxidation with chromic acid, aspidospermine yields a newcrystalline base, which forms a sparingly soluble hydrochloride.Owing t o want of material t'lie base has not' yet been fully investi-gated. It gives none of the colour reactions characteristic ofaspidospermine and its immediate derivatives.EXPERIMENTAL.Preparation of A spidospermine.The finely ground bark was completely extracted with hot alcohol(about 95 per cent.), and the alcohol removed by distillation.Thedark-coloured, viscous residue was extracted with a 20 per cent.solution of acetic acid until the extracts gave only very feeblealkaloidal reactions. The extract was diluted, which caused theprecipitation of a certain amount' of resin, and, wit,hout filtration,treated with a saturated aqueous solution of normal lead acetate,until t'he filtrate no longer gave a precipitate either on dilution oron addition of lead acetate. Thc precipitate was collected, the leadremoved from the filtrate as sulphide, and the solution madealkaline with ammonium hydroxide. A voluminous precipitate wasproduced, which was collected and dried. The filtrate still con-tained some alkaloid in solution, which was readily removed byextraction with chloroform.The residue obtained on distilling offthe chloroform was added t o the crude alkaloid first precipitated.The mixture of bases so obtained was dissolved in a small amountof absolute alcohol, and on keeping, aspidospermine crystallised out.This was collected and purified by recrystallisation from methylalcohol, or, f o r analysis, by sublimation in a vacuum.According t o Hesse (Zoc. c i t . ) quebrachine if present crystalliseswith aspidospermine under conditions similar t o those describedabove. I n the present investigation, however, quebrachine wasnever found t o be present.The alcoholic mother liquors still contained a very considerabl2742 EWINS: THE ALKALOIDS OF QUEBRACHO BARK.PART I.amount of crude alkaloid. Attempts have been made t o work outa satisfactory method of separation of the bases present in thismaterial, butl so far without very much success. Evidence has beenobtained, however, of the presence of a t least two hitherto un-described crystlalline bases, but the amounts so far obtained weretoo small t o permit of further investigation.The separation of aspidospermine from the crude alkaloids bythe method described above is by no means sharp. As alreadystated, however, aspidospermine on hydrolysis with dilute mineralacids givee a new base, deacetylaspidospermine, which can bedistilled under greatly diminished pressure, and is very readilysoluble in light petroleum.The crude alkaloids obtained from the alcoholic mother liquorsafter separation of aspidospermine were therefore boiled with 10 percent.hydrochloric acid for tlwo hours. The solution was thenfiltered and the filtrate made alkaline with ammonium hydroxide.The precipitated bases were collected and dried, and both the driedmaterial and the alkaline filtrate then completely extracted withlight petroleum.The extracts were combined, the solvent removed by distillation,and the residue distilled under 1-2 mm. pressure. The distillate,which collected between 210° and 220°, was dissolved in hot diluteacetone, and on cooling crystals of almost pure deacetylaspidosper-mine melting a t 109O were obtained. The increased amount of baseisolated by this procedure corresponded in some instances with asmuch as 40 per cent.of the amount of aspidospermine originallyobtained.The amount of aspidosgermine present in quebracho bark appearsto vary considerably. From one batch of bark (50 kilos.) a yieldof only 0.06 per cent. of aspidospermine was obtained, althoughfrom smaller bstches yields up to 0.2 per cent. were obtained, Thetotal alkaloid of the bark varies considerably with age. Accordingt o Hestxi (Zoc. cit.), the young bark contains up to 1.4 per cent. ofalkaloid, whilst old bark may contain as little as 0.3 per cent.Aspidospermine, C22H3,0,N2, crystallises from alcohol or lightpetsoleum in needles melting a t 208O. It sublimes under dimin-ished pressure a t about 180°, and can bs distilled under 1-2 mm.pressure a t about 220O.It is fairly readily soluble in most organicsolvents, but almost insoluble in water. It is precipitated by alkalisfrom acid solution as a white, amorphous solid, which becomescrystalline after keeping for a few minutes. Aspidospermine isonly feebly basic, and dow not form crystalline salts. It dissolvesin concentrated sulphuric acid, forming a colourless solution, fromwhich it may be recovered unchanged after prolonged keepingEWINS: THE ALKALOIDS OF QUEBRACHO BARK. PART I. 2743Addition of a crystal of potassium dichromate to this solution givesa brown colorztion, which becomes olivegreen after some time. Onwarming with perchloric acid, aspidospermine gives a rose-redcolour.Aspidospermine is laevorotatory.Determinations of its specificrot’atory power gave the following results :( 1 ) in alcoholic solution at 1B0, a, -1*79O, c=1*81, Z=1 dcm.;(2) in chloroform solution a t 18O, a, -1.6So, c = l * S l , Z=1 dcm.;The corresponding values obtained by Hesse (Zoc. cit.) were- 100.2O and - 83.6O respectively.The formula C,H,O,N,, originally due to Fraude and later con-firmed by Hesse, was confirmed by analysis (Found, C=74*2;H=8*6; N=8*3. Calc., C=:74-5; H=8*4; N=8*0 per cent.), andstill further by the constitution of the bases derived from it,as will be seen below.A determination of the molecular weight by Barger’s microscopicmethod (T., 1904, 85, 286) gave the following result:0.056 in 0.549 pyridine = 0.25 mole. M.W. = 408.A determination of &he meth6xyl groups present in the base was0.2131 gave 0.1406 AgI.OMe=8*7.Aspidospermine theref ore contains one methoxy-group.[a], -99O.[alD -93O.C,,H,O,N, requires M.W. = 356.made according to Perkin’s modification of Zeisel’s method :C,,H,,O,N, requires OMe = 8.7 per cent.Furtherheating with hydriodic acid up t o 300° or rather higher accordingt o Herzig and &!eyer’s method showed that the base contained noN-methyl group.The ,4 c t i o n of Boiling Hydriodic Acid 011, Aspidospermine.Formation of a New Base, Aspidosine, C,,H,,ON,.It was observed that, after treatment of aspidospermine withhydriodic acid for t8he determination of the methoxyl group, theresidue which remained after removal of thO bulk of the hydriodicacid by distillation consisted of needles with a metallic lustre,obviously the periodide of a base.The pure base was obtained inlarger quantity as follows. One gram of aspidospermine was boiledfor one and a-half hours under reflux with 20 C.C. of hydriodic acid(D 1-7). A t the end of this time the excess of hydriodic acid wasremoved by distillation under diminished pressure, the residuesuspended in water and decolorised by sulphur dioxide. The result-ing solution was filtered from a small amount of flocculent material2744 EWINS: THE ALKALOIDS OF QUEBRACHO BARK. PART I.and made alkaline by the addition of ammonia. The white,amorphous precipitate rapidly became crystalline, and was thencollected and dried. The product was almost pure, and weighed0.81 gram.F o r purification the base was recrystallised from alcohol or fromxylene, when it was obtained in well-formed, rectangular prisms orplat'es, which melted a t 244-245O after sintering from about 236O.Repeated recrystallisation failed to effect any change of meltingpoint :0.1260 gave 0.3526 CO, and 0.0994 H,O.0.1634 ,, 13.2 C.C.N, (moist) a t 20° and 763 mm. N=9.3.C,,H,,ON, requires C = 76.5 ; H = 8.7 ; N = 9.4 per cent.Aspidosine is fairly readily soluble in alcohol, ethyl acetate, orxylene; very sparingly so in chloroform or light petroleum, andalmost insoluble in water. I t s solutions in organic solvents becomecoloured on keeping, and the base itself was invariably slightlycoloured. For these reasons accurate determinations of the rotatorypower of the base could not be made'.It is levorotatory, and hasabout [aID -16O in alcoholic solution. I n the presence of alkalithe base gradually dissolves, forming a greenish-blue solution.It dissolves inconcentrated sulphuric acid, forming a pale rose-red solution.AdditIon of oxidising agents, such as potassium dichromate, leadoxide, or nitrous acid produces a reddish-violet coloration. A dropof nitric acid added t o a few drops of the sulphuric acid solutiongives a deep orange-red colour. Crystals of aspidosine moistenedwith ferric chloride are coloured greenish-blue, gradually changingto reddish-brown. I n dilute acid solution the base gives with ferricchloride a reddish-brown colour, which passes through brownish-purple to deep red.Aspidosine Hydriodide, C,gH,,ON,,HI.-This salt was firstobtained during the preparation of the base described above.If t othe solution which has been treated with sulphur dioxide, ammoniais added drop by drop, a crystalline solid separates even while thesolution remains distinctly acid. This proved to be the hydriodideof aspidosine, the free base being obtained from it on furthertreatment with ammonia. The salt is very sparingly soluble incold, but very readily 60 in hot water, from which it crystalliseson cooling in regular octahedra and cubes. Its melting point liesabove 280O.C = 76.3 ; H = 8.8.Aspidosine gives very intense colour reactions.The salt is anhydrous:0.1048 gave 0.0588 AgI. 1=30.3.C,,H,,ON,,HI requires I = 29.8 per centEWINS: THE ALKALOIDS OF QUEBRACHO BARK.PART I. 2745The Action of Dilute Hydrochloric Acid on Aspidospermiue.Formation of Deacetylns~'dosperrnilLe, C,,H,,ON,.One gram of aspidospermine was heated for three hours a t looowith 10 C.C. of 10 per cent. aqueous hydrochloric acid. The result-ing solution was rendered alkaline whea an amorphous base wasprecipitated, which on keeping for a short time became crystalline.It was collected and recrystallised from dilute acetone, when i tformed long, prismatic needles, melting a t l l O - l l l o :0.1356 gave 0.3803 CO, and 0.1092 H,O. C = 76.5 ; H = 8.9.0.1464 ,, 11.4 C.C. N, (moist) a t loo and 767 mm. N=9.36.0.1862 ,, 0.1362 AgI. OMe=9.7.C,,H,ON, requires C = 76.9 ; H = 9.0 ; N = 9.0 ; OMe = 9.9 per cent.I)ecccetylasln'dospermi,Le is readily soluble in most organic sol-vents, but very sparingly so in water. It distils unchanged a t about210° under 1-2 xm.pressure. It dissolves in sulphuric acid t o acolourless solution, which on the addition of a drop of nitric acidgives a violet, or of potassium dichromate a deep brownish-purplecolour. With ferric chloride a magenta colour is produced. Withweaker oxidising agents, such as mercuric acetate, a rose-red colouris obtained, which slowly changes t o violet.Deacetylaspidospermine is feebly dextrorotatory ; a 2.5 per cent.solution in absolute alcohol has [a]= +2*S0.Deacetylaspidosperrnine hcydriodide is obtained when deacetyl-aspidospermins is dissolved in a small quantity of hot dilutehydriodic acid.On cooling the hydriodide separates in stout,rect'angular prisms, melting a t about 243O aft.er sintering from235O. The salt is very sparingly soluble in cold, but fairly readilyso in hot water, or alcohol:0.1134 gave 0.0920 AgI. I=43*8.C20H280N2,2HI requires I = 44.7 per cent.Benzoyldeacetylas~"dosperlnilze is obtained by benzoylating thebase either by Einhorn's method in pyridine solution or by heatinga t looo for one hour with benzoic anhydride. It crystallises fromdilute alcohol in stout rhonibs melting a t 186-187O:0.1017 gave 0.2904 CO, and 0.0720 q0. C = 77.9 ; H= 7.9.0.1246 ,, 7.5 C.C. N, (moist) a t 19O and 764 mm. N=7.0.C,,H,,O,N, requires C = 77.9 ; H = 7.7 ; N = 6.7 per cent.If deacetylaspidospermine is dissolved in a small quantity ofmethyl iodide, the solution warmed for a few moments and thenallowed to remain, a crystalline solid separates, which, when re-crystallised from methyl alcohol, forms well-defined octahedramelting a t 176-177O.It has the composition C,,H2,ON,,2CH,I 2746 EWINS: THE ALKALOIDS OF QUEBRACHO BARK. PART I.0.1046 gave 0*0804 AgI. I=41*5.C,,EI,,0N,,2CHyI requires I = 42.6 per cent'.Formation of Asp'dosper,mine by Acetylation of Deacetyl-asp'dospermirze.That deacetylaspidospermine is derived from aspidospermine bythe removal of an acetyl group is further confirmed by the follow-ing experiment, in which aspidospermine was formed by acetylatingdeacetylaspidospermine. 0*2 Gram of deacetylaspidospermine wasdissolved in 1 C.C.of acetic anhydride, one drop of sulphuric acidadded and the mixture boiled for one minute. The solution wascooled, diluted with water, and rendered alkaline with ammoniumhydroxide. The precipitated amorphous base was collected andcrystallised from methyl alcohol. It separated in needles meltinga t 206-207", and wlien mixed with an equal weight of aspido-spermine showed no depression of melting point. I n all otherrespects also it was identical with aspidospermine. The yield waspractically quantitative.Action of Nitrous Acid 0.12 Deacety1as~'~ospermiize : J'ormationof a LVitronitroso-derivative ( 1).If deacetylaspidospermine is dissolved in dilute hydrochloric acidand treated with sodium nitrite' solution a crystalline solid sepa-rates, which melts indefinitely at about 160--170°, and on recrystal-lisation from a mixture of pyridine and alcohol gives a productmelting a t 220-230° after sintering from about 200O.The sub-stance is obviously a mixture; it contains chlorine, and attemptsto obtain a pure compound were unsuccessful. If the reaction iscarried out in the presence of concentrated hydrochloric acid adeep magenta solution is obtained, from which no crystallineproduct could be isolated. If, however, the reaction is carried outin acetic acid solution a pure substance is obtained.0.5 Gram of deacetylaspidospermine was dissolved in 5 C.C. of a10 per cent. solution of acetic acid. To the cooled solution satur-ated aqueous sodium nitrite solution was added drop by drop untilthe separation of a crystalline solid appeared to be complete. Thesolution was allowed to remain for about an hour, when the crystal-line solid was collected, washed with water, and recrystallised fromdilute acetone, from which i t separated in pale yellow prisms, melt-ing and decomposing a t 155-156O.Recrystallisation from amixture of pyridine and alcohol gave a similar product, having thesame melting pointEWINS: THE ALKALOIDS OF QUEBRACHO BARK. PART I. 21410.1179 gave 0.2668 CO, and 0.0758 H,O. C = 61-7 ; H = 7.1.0.1182 ,, 14.6 C.C. N, (moist) a t 20° and 753 mm. N=14*1.0.11794 ,, 0.1084 AgI. OMe = 8.0.C2UH2,04N4 requires C = 62.2 ; H = 6.7 ; N = 14.5 ;OMe = 8.0 per cent.Analysis of this product gave some trouble, since i t was difficultwithout extraordinary precautions t o bring about complete reduc-tion of the easily liberated nitric oxide.The results appear t o indicate that the substance is in all proba-bility a nitronitrosodeacetylaspidospermine, and its formationperhaps points to the presence in the nlolecule of a reduced quino-line nucleus.The substance undergoes decomposition by boilingwith alcohol, but the isolation of the corresponding nitro-derivativehas not so far been accomplished. I n the presence of acids morecomplex decomposition appears t o take place.Nitroiaitrosodeacetylaspidospermilze ( 1 ) forms pale yellow prisms,melting and decomposing a t 155-156O. It is very readily solublein acetone o r pyridine, less readily so in alcuhd, and very sparinglyso in water.When dis-solved in concentrated sulphuric acid or warmed with dilutemineral acids a brilliant reddish-purple solution is produced. Withphenol and sulphuric acid it gives a dark green solution, which ondilution becomes deep red, With ferric chloride solution no colouris produced.Boiling hydriodic acid (D 1.7) converts nitronitrosodeacetyl-aspidospermine into aspidosine.Its aqueous solution reacts faintly acid.Oxidution of Aspidospermine with Chromic Acid.Two grams of aspidospermine were dissolved in 40 C.C. of dilutesulphuric acid (25 per cent. by weight). Three grams of chromicacid were gradually added in small quantities to the boiling solu-tion, and the mixture was then boiled for five hours.The resultingsolution was treated with hot saturated barium hydroxide solutionuntil distinctly alkaline. The hot solution was filtered underpressure, the precipitate repeatedly extracted with boiling wateruntil the extracts no longer gave alkaloidal reactions, and the' com-bined filtrates were completely freed from sulphuric acid andbarium. The aqueous liquid was then conceatrated to small bulk,made faintly acid towards Congo-red with hydrochloric acid, andfurther concentrated until crystallisation commenced. The solutionwas aet aside, and after some time the crystalline product wascollected and recrystallised from absolute alcohol. The productproved t o be the hydrochloride of a base which was set free' b974.8 BRADBURY AND WEIZMANN :ammonia and crystallised from ethyl acetate in stout prisms, melt-ing a t 192-193O. The base is very sparingly soluble in water, butfairly readily so in alcohol, ethyl acetate, or chloroform. It givesvery marked i.eactions with alkaloidal reagents, but gives none ofthe colour reactions characteristic of aspidospermine or its deriv-atives already described. The' yield is only about 5 per cent. ofthe weight of aspidospermine employed, arid on this account a fullinvestigation of the base has not so far been possible.The hydrochloride forms plates which melt a t 286--287O, and issparingly soluble in water or in cold alcohol :09956 gave 0.2104 CO, and 0.0706 H,O. C = 60.0 ; H = 8.2.0.1322 ?, 0.0638 AgC1. Cl=ll.S.C,,H,,O,N,,HCl requires C = 59.9 ; H = 8.3 ; C1= 11.8 per cent.From these results the most probable1 formula for this basewould appear t o be C,,H2,0,N,, but this cannot be said t o beestablished with any degree of certainty a t present.WELLCONE PHYSIOLOGICAL HRSP,.~ I:CII I,ABORATORI IV,HERNE HILL, S E

ISSN:0368-1645    

DOI:10.1039/CT9140502738

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

2748 BRADBURY AND WEIZMANN :CCLV1.-Some Homologues of Alizarin.By HARRY BRADBURY and CHARLES WEIZMANN.BENTLEY and Weizmann (T., 1908, 93, 435) have shown that whenhemipinic anhydride condenses with veratrole and with pyrogalloltrimethyl ether, in the former case the normal benzoylbenzoic acidis formed, but in the latter one methoxy-group is displaced byhydroxyl, the condensation in both cases being affected by meansof aluminium chloride. The object. of the present work was toinvestigate the condensations of hemipinic anhydride and4-methoxyphthalic anhydride with o-xylene, and the results werequite analogous to those just mentioned, the methoxy-groups beingalso displaced by hydroxyl.The condensation of hemipinic anhydride with o-xylene fur-nished a dihydroxy-2-xyloylbenzoic acid, which, as it gave twodimethylalizarins on heating with sulphuric and boric acids, musthave the constitution I or 11:/\/co\/\%l,OH coOH/\/ \,'\MeI bO,H ,,,!Me OH /CO,H I /Me \/ \/OH\/(1. ) (11.SOME HOMOLOGUES OF ALIZARIN.2749The constitution of one of the two dimetliylalizarins (melting a tthe higher temperature) was determined by oxidation with potass-ium perinanganate in alkaline solution, when pyromellitic acid wasobtained. This could only have been formed according to thescheme :OH coThe constitution of the other dimethylalizarin must be either111 or IV, according as the original acid has the constitution I orI1 respectively :OH CO OH CO Me(11 I . ) ( I V . )owing to lack of material it has not yet been possible t o decide this.The condensation of 4-methoxyphthalic anhydride with o-xyleneproceeds similarly.Two hydroxyxyloylbenzoic acids were obtained,melting respectively a t 228O and 184O. The former, on fusion withpotassium hydroxide, gave m-hydroxybenzoic acid, and when con-densed in the usual way gave only one hydroxydimethylanthra-quinone, the formation of which points t o the acid having theconstitution V or V I :v. )and the quinone VII or VIII:co Mt!(VII.) ( V I I I . )EXPERIMENTAL.Dih ydrozy-2-xyio yl b enzo ic A cid.Ten grams of hemipinic anhydride were dissolved in 50 grams of0-xylene, and 15 grams of aluminium chloride gradually added.The mixture was then heated on the steam-bath for about sixVOL.cv. 8 2'750 BRADBURY AND WEIZMANN :hours, when it was poured into ice and water and steam passedthrough to remove the excess of o-xylem. When cold the solid wascollected and purified by solution in ammonia and precipitationwith hydrochloric acid. The product from which no isomeric acidcould be obtained crystallised from acetic acid in small needlesmelting a t 238O:0.1242 gave 0.3039 CO, and 0.0522 H,O. C=66.78; H=4*65.C,,RI40, requires C = 67.13 ; H =4*90 per cent.Dime t hylalizarins.The above acid was heated with sulphuric acid together with asmall amount of anhydrous boric acid for a short time a t 130°,and the liquid after cooling was poured into ice and water, whenthe dimethylalizarins separated as an orangeyellow powder. Thesewere separated by making use of their solubility in acetic acid.The dimethylalizarin melting a t 198O was readily soluble, whereasthat melting a t 276O was spaiingly soluble; each crystallised inorange-yellow needles, and resembled ordinary alizarin in its pro-perties.The compounds readily dissolved in sodium hydroxide t oa deep purple solution, which dyed mordanted cotton, diff erentshades being cbtained according to the mordant used.The substance melting a t 276O was analysed :0.0682 gave 0.1780 CO, and 0.0266 H,O. C='i'1*26; Ht4.33.Cl&€lz04 requires C = 71.64 ; H = 4-47 per cent.The dimethylalizarin melting a t 276O was oxidised with potass-ium permanganate in alkaline solution, and after removal of %heexcess of permanganate the filtered liquid was evaporated todryness and the residue extracted with alcohol.On evaporationof the filtered extract and acidifying, pyromellitic acid wasobtained. .Wydroxy-2-xy lo ylb enzoic Acids.The condensation of 4-methoxyphthalic anhydride and o-xylenewas carried out in E n exactly similar manner to that employed inthe preparation of the dihydroxy-2-xyloylbenzoic acids. Theproduct, after being purified by dissolving in ammonia and precipi-tation by hydrochloric acid, was boiled with benzene. Very littleappeared €0 pass into solution, and the residue after filtrationapparently consisted of only one acid. This was crystallised fromacetic acid, in which it was fairly readily soluble, and the solutionon concentration deposited small crystals melting a t 228O.Thefusion of this acid with potassium hydroxide was carried out asfollows: Five grams were gradually added t o 15 grams of fusedpotassium hydroxide, and the mixture was heated a t 270-280SOME HOMOLOGUES OF ALIZARIN. 2751for three hours. The cooled mass was dissolved in boiling water,and the' solution acidified with dilute sulphuric acid. On coolingan acid crystallised out, and which, when recrystallised from hotwater, melted a t 200° and was identified as m-hydroxybenzoic acid.The filt'rate from the above acid was extracted several times withether, and after evaporating the ether a residue remained, butthe dimethylbenzoic acid has not yet been isolated in a purecondition.The benzene solution mentioned above was evaporated to asmall bulk, and crystals were obtained which, after further crystal-lisation from benzene, melted a t 184O.The amount, however, ~ 7 a sonly an exceedingly small proportion of the total yield of acid.Hydro x ydim e t h plant hra puino ne.The acid melting a t 228O was-he'ated with sulphuric and boricacids, and on pouring the mixture into water a pale green powderwas obtained. This was collected and crystallised twice fromacetic acid, yielding small, pale green needles, melting a t 210O.No other quinone was detected in the product:0.1462 gave 0.4066 (30, and 0.0630 H,O. C=75.86; H=4.78.Cl,H,,Os requires C = 76-19 ; H = 4.77 per cent.P.relmratio?z of 4 - N e t hoxypJh th n Zic A cid.In the first' experiments 4-methoxyphthalic acid was prepared byBeiitley and Weizmann's method (loc.c i t . ) . This was found,however, to give a comparatively poor yield, and the followingprocess was devised. 4-Hydroxyphthalic acid (1 mol.) was dissolvedin xylene, and methyl sulphate (4 mols.) and anhydrous potassiumcarbonate (4 11101s.) were added in this order. The mixture wasthen heated in an oil-bath f o r three hours a t 135-140°, andagitated. Water was added to the cooled product, and the xylenelayer separated from the aqueous portion. The latter was extractedseveral times with ether, and the ethereal extract added t o thexylene layer. The ether was removed by distillation and the' xyleneby means of a current of steam. The oil remaining was dissolvedin ether, the solution dried and evaporated, and the residuedistilled under diminished pressure. The yield of methyl 4-methoxyphthalate varied from 80 to 90 per cent., depending on theduration of the passage of steam in which it is slightly volatile.The ester was hydrolysed in the usual way by means of a solutionof potassium hydroxide in alcohol, and the acid converted intothe anhydride.TIIE UNIVERSITY,MANCHESTEK

ISSN:0368-1645    

DOI:10.1039/CT9140502748

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

2752 CAVEN AND SAND: THE DISSOCIATION PRESSURESCCLVI1.-The Dissociation Pressures of the AlkaliBicarbonates. P a ~ t 11. Potassiu~i , Rubidiunz,and Caesium Hydrogen Carbonates.By ROBERT MARTIN CAVEN and HENRY JULIUS SALOMON SAND.IN a former paper (T., 1911, 99, 1359) we recorded the results ofour study of the thermal dissociation of sodium hydrogen carboii-ate, and showed that sodium carbonate monohydrate was notformed from the bicarbonate within the temperature limits of ourexperiments. It was stated, however, by Hermann ( J . pr. Ghem.,1842, 26, 312) that the sesquicarbonate, Na,H,(C03),,3H,0,results when the hydrogen carbonate is heated to 200O. Theformation of the sesquicarbonate from the hydrogen carbonate isdenied by Lescoeur ( A ? m C'him. Phys., 1892, [vi], 25, 423), butwe determined t o establish the simpler manner of decompositionof the hydrogen carbonate under the conditions of our experimentsby the direct estimation of the proportion between water vapourand carbon dioxide in the gaseous phase.For this purpose a glass reservoir of 50 C.C.capacity was joinedon the one side through a tap to the tube leading from the flaskcontaining the heated bicarbonate, and was connected on the otherside with calcium chloride and soda-lime absorption tubes. Thereservoir and absorption tubes were exhausted; the former wasthen heated above looo, and the tap communicating with theAask opened so that the gaseous mixture might expand into thereservoir without aqueous condensation. After a few seconds thetap was closed again, and the water and carbon dioxide now inthe reservoir were carefully transferred to the absorption tubes.It was advantageous to allow some of the water to condense inthe reservoir, and subsequently to remove i t by slow evaporation,and an arrangement was made to carry forward the last traces ofwzter-vapour and carbon dioxide in a stream of purified air.The following results were obtained with sodium hydrogencarbonate :Temperatures Molecularof thermostat.H,O. CO,. ratio H,O : CO,.101.5" 0.0118 0.0295 1 : 1.020.0108 0-0259 1 : 0.98 101.8"These results were sufficient to show that water is not retainedto form the hydrated sesquicarbonate, Na,H,( C03),,3H20, wheOF THE ALKALI BICARRONATES. PART 11. 2753sodium hydrogen carbonate is heated under the conditions of ourexperiments, alt'hough they do not preclude the possibility of com-bination between sodium carbonate and sodium hydrogen carbon-ate to form an anhydrous intermediate salt such as Na,H,(CO&.Po t assiu?n Hydrogen Car b o nat e .It was mentioned in the former paper that Lescceur (*4?717.Chim.I'hys., 1892, [vi], 25, 423 *) measured the dissociationpressure of sodium hydrogen carbonate, obtaining results muchlower than those obtained by us. The apparatus employed byLescoeur (A'nn. Chim. Phys., 1889, [vi], 16, 389) differed in prin-ciple from ours, and consisted of a barometer tube surrounded bya vapour jacket. The substance was contained in a small tube inthe space above the mercury, and gas could be withdrawn fromthis space by means of a narrow open tube which passed down-wards through the mercury.It is noteworthy that the vapourpressuree of potassium hydrogen carbonate observed by Lescceurare slightly higher than ours a t the lower temperatures, butapproach closely to them a t 127O, the highest temperature at whichobservations were made by Le'scceur. These results are shown bythe dotted curve on our diagram.I n the study of the thermal dissociation of potassium hydrogencarbonate the posddity of the formation of a hydrated compoundof normal carbonate and hydrogen carbonate, or of the retentionof water by the normal carbonate, had first t o be considered. Sincethe temperature of sensible dissociation of potassium hydrogencarbonate is considerably higher than that of the sodium salt, theformation or" intermediate compounds containing water seemeda priori less likely than in the case of sodium.The anaIysis of thegaseous phase resulting from the decomposition of potassiumhydrogen carbonate provided, however, direct evidence that waterwas not retained to form such intermediate compounds.Measurements made in the manner described above yielded thefollowing results :Temperature MolecuIarof thermostat. H,O. CO,. ratio H,O : CO,.145" 0.0080 0.0253 1 : 1.28160.2' 0.008'9 0.0232 1 : 1.07161.1" 0.0068 0.0164 1 : 0.98Thus it is shown that potassium hydrogen carbonate dissociates* This reference was wrongly given as Ann. Chim phys., 1893, [vi], 28, 423-into normal carbonate, carbon dioxide, and water2754 CAVEN AND SAND : THE DISSOCIATION PRESSURESThe dissociation pressures of potassium hydrogen carbonate weremeasured in %he wme way as those of sodium hydrogen carbonate,and the results obtained are here tabulated, together with thosecalculated from the equation :logp=a-bjT,where a= 10.832 and b =3420.It should be remarked thaE a t 120° and upwards the vapourpressure of mercury beconies appreciable, and consequently a cor-rection has been applied t o the pressure readings for the highertemperatures.Potassium Hydrogen Carbonate.Pressure in mm.of mercury.Temperature.151.8'156.0147.8137-7127-2119.1104.600.276.363.792.5103.5116-4127.4138.4146.3153.4155.4Rising.610.6733.0--3 1-257.7111.2192.0322.8471.4663.1713.8Falling.-503.1314.7184.1124.156.G24.611.44.1-Calcuiated.60472450632019312059.626.111-04-729.966-0112196330473647706These experimental values are shown in the figure in relation t othe calculated curve, together with those of sodium, rubidium, andcmiurn.It may be pointed out t'hat in this case the experimentalvalues lie along the calculated curve throughout the whole rangeof temperature.Heat of Dissociation of Potassium Hydrogen Carbonate.From the value of the constant b =3420 the heat of dissociationof potassium hydrogen carbonate per gram-molecule of gas pro-duced is calculated by means of the equation q =log, lOBb to be15,730 calories, since log,l0=2-30 and B=2.As in the case ofsodium hydrogen carbonate, the heat of dissociation, x, of twogram-molecules of potassium hydrogen carbonate may be calculatedfrom the thermal equation:2LKHCO-J = [K,CO,] + (H,O 1 + { CO,} - X OF THE ALKALI BICARBONATES. PART 11. 2755The heats of formation from their elements of 1 gram-moleculeof pot'assium hydrogen carbonate and potassium carbonate are,according to de Forcrand (Compt. rend., 1909, 149, 719), respec-tively 231?630 and 275,370 calories, whence, accepting the heats offormation of water as steam a t looo, and of carbon dioxide to be58,060 and 97,000 calories respectively, x= 32,830, instead of31,460, as calculated from our results.Rubidium and Caesium Hydrogen Carbonates.Rubidium and msium ++ hydrogen carbonates were prepared from,the normal carbonates according to de Forcrand's method (Compt.rend., 1909, 149, 719) by exposing concentrated solutions of thelatter salts to an atmosphere of carbon dioxide in a desiccatorcontaining sulphuric acid.I n some earlier experiments on thedissociation pressure of rubidium hydrogen carbonate a small pro-portion of the normal carbonate was mixed with it previous to itsintroduction into the reaction flask, but, owing to the very hygro-scopic nature of the latter salt, it was judged better to produce anamount of it sufficient to secure the satisfactory reversal of thereaction by heating the bicarbonate in the reaction flask itself,and pump?ng out the dissociation products.Since i t had beenshown that potassium as well as sodium hydrogen carbonate yieldsas dissociation products equirnolecular proportions of water-vapourand carbon dioxide, it was at first thought safe to assume t'hatrubidium and cEsium hydrogen carbonates would behave similarlywhen heated; but, owing t o difficulty in interpreting the experi-mental results fo be recorded below, the composition of the gaseousphase was estimated in the case of these salts also.The dekrmination of the dissociation pressures of rubidium andcaesium hydrogen carbonates was carried out in the apparatuspreviously employed. Sixteen grams of the rubidium salt wereheated to atout 160°, and gas was repeatedly withdrawn at thattemperature until successive readings after restoration of pressureagreed. I n the case of caesiuni hydrogen carbonate, about 18 gramswere employed, and the salt was heated to 163O until the pressurebecame constant after successive withdrawals of gas.Retardationeffects, such as were observed in the case of sodium hydrogencarbonate, which necessitated the employment of a much largerquantity of the reacting substance, did not occur with either salt.Owing, however, to the lengthened heating a t high temperatures,and the fact that the temperature of the air above the sulphuric* Cmium carbonate could not be purchased, but fortunately the amount of thissalt available was sufficient for our experiments2756 CAVEN AND SAND: THE DISSOCIATION PRESSURESacid bath was slightly lower than that of the acid in which thethermometer and reaction flask were immersed, distillation ofmercury within the thermometer took place, and consequently thereadings might be several degrees tloo low. This difficulty waspartly overcome by fixing the thermometer so that the top of themercury column was always above the level of the acid, the errorthus introduced being negligible.When, however, small frag-ments of mercury thread appeared in the upper part of the thermo-meter, it was necessary to reject the readings.The following are the experimental results obtained, togetherwith those calculated from the formula log p=u - b /T, where forRbHCO,, n =12712, b =4300, and for CsHCO,, a=16'930,b = 6300.Rubidium Hydrogen Carbonate.Temperature.160'153.5135.3120.5109.397.391.261.512.7106.5120.1137-3146.8151.9161-0170.0164-0158.4151.5143.2135.2121.2112.995.815.011 1.4136-5147-1153.5158.6Pressure in mm.of mercury.Rising. Falling. Calculated.- 594.1 605- 451-7 427 - 197.9 152 - 116.5 60.9 - 75.5 29.2 - 49.3 12.6- 40.9 s.0 - 18.4 0.7 - 0.7 0.051.5 - 24.197.0 - 59.4/ 7211.9 - 171323-1 - 296392 405.9 -623.7 - 6381,038.4 - 1,045 - 750.0 747 - 552.5 556 - 392.2 383 - 247.8 240 - 179.0 151 - 96.3 63.8 - 75.4 37-2 - 49.8 11-3 - 0.0 0.076.0 - 33-6217-1 - 163343-2 - 300446.3 - 427562-4 - 56OF THE ALKALI BICARBONATES. PART 11.Ca esizc m Hydroge,n Car b o m t e .Temperature.163.0"160.1163.1142.7133.611G.5103.8s9-6103.0117.9133.1140.0151.6158.1169.9172.2177.0179.8178.1175.4172.7166.1157-8152.4144.5135.3Tliese results differPressure in mm.of mercury.h .Rising.322.8- ------28.847.579.3100.7168.9234.8502.1599.7847.11,029-5--------Falling.-267.01SO.0115.981.046.525.316.3----------915.1755.0614.1399.8241.0183.3130.691.5in an iinportaiit wayCalculated.30324214059.627.35.71.60.41-56.524.047.41242076076018511,03892 17596243 8220213269.231.62757from those obtainedwith potassium hydrogen carbonate. For whilst the experimentalvalues lie along the curve throughout its whole length in the caseof the potassium salt, it is only the pressures above 158O withrubidium hydrogen carbonate, and above 1 6 5 O with czsium hydro-gen carbonate, that agree with the values calculated from theformulae.Discordant pressure values were obtained a t the lower tempera-tures in the case of sodium hydrogen Carbonate, but these wereshown t o be due t o retardation, ascending values being too low,whilst descending values were too high.Here, however, ascendingand descending values agree; they therefore appear t o indicate atrue cquilibrium. Consequently no single curve of the typelog p=a - b / T can be drawn t o represent the experimental valuesobtained in the dissociation of rubidium and czsiuin hydrogencarbonates, and i t became necessary to investigate the cause of theanomaly.This could best be done by the analysis of the gaseous phase,which was consequeiitly carried out.with both these salts, but ingreater detail with rubidiuiii hydrogen carbonate. About 19 grainsof this latter salt, pulverised and dried over sulphuric acid in 2758 CAVEN AND SAND: THE DISSOCIATION PRESSURESvacuum desiccator for several days, were heated in the reaction flaskto 120° f o r twent,y-four hours; the flask was then exhausted, andany wat'er vapour that had been evolved was drawn off through acalcium chloride tube. The delivery tube was then attached toweighed calcium chloride and soda-lime tubes, and the flask washeated to 170O. The products evolved a t this temperature werepassed through the absorption tubes by maintaining a reducedpressure on the further side until it was judged that sufficientC70, 8Temperatzwc.absorption liad taken place.The flask was then exhausted, andthe whole of the water-vapour and carbon dioxide collected in theabsorption tubes. In two successive experiments 0.0628 and 0-0770gram of water and 0.1400 and 0.1835 gram of carbon dioxide werecollected; these correspond with the molecular ratios H20 : C02=1 : 0.94 and 1 : 0.98. Thus it was shown that water-vapour andcarbon dioxide ar0 evolved in approximately equimolecular pro-portions from rubidium hydrogen carbonate a t 170O.The reaction mixture was then, allowed to cool $ornewhat, aiiOF THE ALKALI BICARBONATES.PART IT. 2759tlie proportions between tlie two components of the gaseous phasewere estimated a t temperatures approaching and correspondingwith those a t which anomalous pressure values appear on the disso-ciation curve. Owing to the small quantities of gas evolved intheso experiments i t was necessary t.0 allow the absorption tocontinue over lengthened periods of time, amounting a t the lowertemperatures to two days ; nevertheless, interesting results wereobtaiiied under parallel conditions, which are liere shown :Temperature. H,O. co,. RIolecular ratio H,O : CO,.145' 0.0197 0.0507 1 : 1.046132 0.0147 0.0343 1 : -957131 0.0053 0.0108 1 : -847127 0.0087 0.0164 1 : -770125 0.0180 0.0336 1 : -763Before a definite interpretation could be given t o the undoubteddeficiency of carbon dioxide or excess of water-vapour in thegaseous phase a t the lower temperatures i t was necessary to knowthe ratio between the amounts of these substances remaining inthe residue.To discover this ratio a fresh experiment was carriedout with 1 gram of carefully dried rubidium hydrogen carbonate,which was heated in the silica flask previously employed in theexperiments with sodium hydrogen carbonate, this flask being usedto avoid the possibility of the absorption of carbon dioxide byglass. I n three successive experiments carried out at 123O tliefollowing molecular ratios were found : H,O : CO, = 1 : 0.731,1 : 0.648, 1 :-0.662; but on ignition of the residue this ratio wasfound to be 1 : 0.995.Thus i t was shown that, excess of waterpresent in the gaseous phase a t the lower temperatures is extrane-ous water, and is not derived from the preferential loss of waterby the salt itself.Similar experiments carried out with a small quantity of c&umhydrogen carbonate pointed to a like conclusion. A t 1 7 3 O and182O the molecular ratios found were H,O : CO,=1 : 1.009 and1 : 1-05 respectively; a t lower temperatures water-vapour wasslowly evolved even after all the carbon dioxide had beenexhausted.It had been concluded that the rubidium, as well as czesiumhydroger, carbonate, prepared for and employed in these experi-ments was pure and dry, because the loss incurred on ignition oftho former saltl closely agreed with theory; but it remained possiblethat this agreement was due t o compensation, and t h a t t'lie productwas really a mixture of rubidium normal and hydrogen carbonates,together with some water.A further experiment in which 1 gramof the salt dried as described above was heated, and all the evolvedproducts were collected and weighed showed that it containe2'760 CAVEN AND SAND: THE DISSOCIATION PRESSURES0.0804 gram of water instead of 0.0614 gram, and 0.1277 gramof carbon dioxide instead of 0.1500 gram, the total loss on heatingbeing 0.2081 gram instead of 0.2114 gram according t o theory.The anomalous pressure values obtained a t the lower temperatureswith rubidium and czsium hydrogen carbonates are probably due,there'fore, to tlhe following cause.The salts employed contained a certain proportion of the normalcarbonates, together with some water tenaciously held in spite ofcareful drying.This water was not present in sufficient amount,however, perceptibly to interfere with the equimolecular pro-portions between the water vapour and carbon dioxide evolvedfrom the bicarbonate a t high temperatures and pressures after theremoval of some of the gas; as was proved by direct experiment(see p. 2758), and by the fact that successive readings agreed.When, however, the temperature was lowered and absorption tookplace, excess of water vapour, although small as regards its abso-lute value, would become relatively great owing to the smallnessof the total amount of gas left, and would thus become operativein greatly increasing the observed pressures.The anomalies that'exist in the lower parts of ths dissociation pressure curves ofrubidium and caesium hydrogen carbonates are therefore ultimatelyto be attributed t o the exceedingly hygroscopic nature of thenormal carbonates of these metals. It may here be pointed out,moreover, that the curves would tend t o become' too shallow onaccount of any small excess of water vapour present in the gaseousphase.Heats of Dissociation of Rqchidz'um and Cesium HydrogenCarbonates.From the equation p=log,lORG, when b=4300 and 6300respectively, the heats of dissociation are calculated to be: forrubidium hydrogen carbonate 19,780 cals. and for czesium hydrogencarbonate 28,980 cals.According t o de Forcrand (Compt.rend., 1909, 149, 719) theheats of formation per gram-molecule are 231,920 and 274,900 cals.for RbHCO, and Rb,CO,, and 232,930 and 274,540 cals. respectivelyfor CsHCO, and Cs+20,; whence the heats of dissociation pertwo gram-molecules of RbHCO, and CsHCO, are calculated to be33,800 and 36,260 cals. respectively, instead of 39,560 and59,960 cals. derived from our results.We are unable to offer any explanation of the discrepancybetween our thermal values and those of de Forcrand. Thesevalues might be approximated by the reduction of the value of bin the equation log p = a- b I;, which would involve a reductioOF THE ALKALI BTCARBONATES. PART 11. 2'761in the steepness of the corresponding dissociation-pressure curves.The increasing steepness from potassium to cmium is well shownin the figure by the increased curvature apparent midway in'thecurves, which is especially apparent with caesium.It has been shown above, however, that the only cause of errorwhich we a t present recognise, that is, the departure from equi-molecular prqportions in the gaseous phase, would have the oppositetendency of making the curves too shallow.Consequently wecannot admit the validity of reducing the values of the constantb in the two equations. On the other hand, whilst we cannotcjffer any general criticism of :he conclusions of de Forcrand, i tmay be pointed out that they are based on diminishing values forthe heats of formation of the normal carbonates from potassiumto czsium, namely, K,CO, = 275,370 cals., Rb,CO, = 274,900 cals.,Cs,CO, = 274,540 cals. ; values which we should certainly a prioriconsider improbable.The results of our experiments on the dissociation pressures ofthe alkali bicarbonates show, not only that the stabilities towardsheat of these salts increase with rise of atomic weight and accom-panying increase in electropositiveness of the metals, but also thatsodium hydrogen carbonate is widely separated from the otherthree salts in stability.Thus there is furnished another example of the fact that abreak occurs in the gradation of properties of compounds of thealkali metals a t the1 point of transition from the short t o the longperiods in the periodic classification of the elements.We desire to express our indebtedness to the Research FundCommittee of the Chemical Society for a grant which has defrayedpart of the cost of this investigation.UNIVERSITY COLLEGE,NOTTIK GHAM.THE SIR JOHN CASSTECHNICAL Iwwrrre, LONDON

ISSN:0368-1645    

DOI:10.1039/CT9140502752

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

2762 WERNER : THE ISOMERIC TRANSFORMATION OFC C t V I 1 I. - The Is0 n ~ e r ic T? -a 12 s f omnatioyb of Ammom’ 11 mMethyl Sulphate, and of Substituted Anhmo?iizcmMethyl Xulphates ; the Intewxction o f Amivzesaid Methyl Sdphate.By EMIL ALPHONSE WERNER.IN a recent communication (this vol., p. 925) containing an accountof the study of the’ decomposition by 4ieat of the methyl sulphatesof certain isocarbamides, it was pointed out that ammonium methylsulphate can evidently undergo isomeric change when heated, inaccordance with the equation :NH,*MeSO, = NH3Me*HS0,.This interesting readion, which does not appear t o have beenhitherto rccorded, was only noticed as a qualitative change inconnexion with tlie investigation referred t o above. A more inti-mate study of the change has now been made, the results of whichhave shown that an isomeric transformation on the line indicatedabove is apparently a property common to all substituted ammon-ium methyl sulphates, where such an interchange in the position ofa hydrogen atom and a methyl group is possible.Thus when methylammonium methyl sulphate, the simple pre-paration of which from ammonia and methyl sulphate is describedfurther on, is heated it gradually changes t o the isomeric dimethyl-ammoniuin hydrogen sulphate,NH,Me*MeSO, = NH,Me,*HSO,,and the further progress and limitl of the isomeric traiisformationmay be expressed by the general equations:NH2RR/*MeS0, = NHRR/Me*HSO,NHRR/R”*MeSO, = NRR/R//Me*HSO,.Whilst the alcohol radicles may be variants, tlie isoinerisationappears to be restricted to the methyl sulphates, since neitherammonium ethyl sulphate nor ammonium n-propyl sulphate wasfound to undergo any isomeric change.Decomposition with theformation of ammonium hydrogen sulphate and ethylene andpropylene respectiveIy was the only result of the action of heaton these two salts.The results of a quantitative study of the extent of isomericchange with rise of temperature in the case of ammonium andinethylammonium methyl sulphates are given in the tables below;the time of heating was fifteen minutes in all the experiments; thiscomparatively short period was chosen, as preliminary experimentsshowed that the velocity of the isomeric change was chiefly a funcAMMONIUM BIETHSL SULPHATE, ETC.2763tion of the temperat'ure. Since the methyl sulphates under investi-gation were found t o 'be neutral in reaction, the progress of thechange was readily measured by determining the acidity developedin the product ah the end of each experiment.TABLE I,*NH4*M(?S0, = NH,&lIe*€ISO,.I'empera-ture.110-120"135-145160180-185200-205Tempera-ture.100-105°135-140150- 15 517G-175190-200Per cent. ofisomeric change.7.09.411.314.325.8Tempera- Per cent. of220-230' 46.3240-250 7 3 4250-260 85.9275 97.2ture. isomeric change.TABLE II.*NH3Me*&CeS0, = NH,Me,-HS04.Per cent. ofisomeric chaaige.2.66.47.28.313.9Tempera- Per cent. of2 10- 4 20" 35.1230-240 60-3-2 50--260 81.3275 97.5ture. isomeric chmgr.* The nnmbers for the temperatures from 240" upwards are slightly liigher thanthe true values, on account of the sinall amount of secondary change, referred to inthe experimental part.It will be' seeii from the above that in both cases the amount ofisomeric change is small until a temperature of about 220° isreached; beyond this it proceecb rapidly, and is almost completea t 275O, and with the exception of a slightly greater amount ofisomerisation for the lower temperatures in the case of ammoniummethyl sulphate these is practically no difference in the generalorder of the change for these two salts.The influence of time onthe velocity of isomeric change is small even just below 220O; thusin the case of ammonium methyl sulphate after heating for onehour a t 200-205° the percentage of isomerisation was raised from25.8 (for fifte'en minutes) t o 34.2, whilst with the methylammoniuinsalt a t 210-220° there was an increase from 34.1 t o 46.9 per cent.for the same difference in period.A few different types of substituted ammonium methyl sulphateshave been examined, all of which apparently undergo an isomericchange, and in the1 case of derivatives containing more complexalkyl groups or a phenyl group this proceeds more readily thanwith the methyl sulphates recorded abo've ; for example, methyl-dipropylammonium and plienyldimethylammonium methyl sul2764 WERNER : TIIE ISOMERIC TRANSFORMATION OFphates were found t o undergo isomeric change to the extent ofabout 35 and 48 per cent.respectively a t 140°, wliilst even a t looothere was a very appreciable amount of change.It is hoped to make a systematic quantitative study of a numberof different methyl sulphates as soon as opportunity permits.As regards the mechanism of this isomeric change it appearsvery probable that dissociation, as the first step towards morestable equilibrium, precedes the formation of the isomeride ; thuswhen ammonium methyl sulphate is heated it will dissociate withthe production of methylamine and sulphuric acid rather thanammonia and the very unstable methyl hydrogen sulphate, andfrom the union of the disso_ciation products the still more stablemethylammonium hydrogen sulphate will be formed. This explana-tion is in agreement with the conditions under which the isomericchange has been shown to take place, and also with the fact thatthe methyl sulphates of the feeble (benzenoid) ammonium basesundergo isomerisat.ion readily a t correspondingly lower tempera-tures. Considered from a practical point of view, the recognitionof this general isomeric change is likely to prove of some value,since it appeazs to place in our hands a method more simple thanany of those hitherto available for the preparation of varioussubstituted methylammonium bases, more particularly on accountof the ease with which the methyl sulphates may be prepared fromthe interaction of the amines and methyl sulphate, in accordancewith the general equations :(a) NH,R + Me$O, = NH,RMe*MeSO,.( b ) NHR, + Me2S0, =NHR2Me*MeS0,.It also explains certain discrepancies in the results which have beeiipublished hitherto with regard to the above reactions.Thus, whilstClaesson and Lundvaal ( B e y . , 1880, 13, 1699) have shown thatammonia and aniline respectively react with methyl sulphateaccording to equation (a), they state that in the case of diethyl-amine and methyl sulphate the products formed are diethyl-ammonium and dimethyldiethylainmonium methyl sulphates, andmore recently Ullmann (9nnaZen, 1903, 327, 104), who hasexamined the behaviour of aniline and a number of its differenthomologues towards methyl sulphate, has arrived at the conclusionthat in the case of aromatic amines the interact.ion does not followthe course described by Claesson and Lundvaal (Zoc. cit.), but forprimary amines is to be represented by the general equation:2NH2R + Me,SO, = NH,R*MeHSO, + NHMeR ;for example, with aniline the products formed are stated to beaniline methyl sulphate, methylaniline, and a certain amount ofdimethylaniline.The experimental conditions adopted, more eepeciAMMONIUM METHVL SULPHATE, ETC. 2 7-6 5ally by Ullniann, were such that much heat was allowed to de,velopduring the interactions, with the result that more or less isomericchange must have taken place, to which cause must be attributedthe different conclusions arrived a t regarding the general order ofthe interaction. The results of experiments with several differentamines, aliphatic and aromatic, have shown that if care be takento avoid anything more than a slight development of heat, thereactions with methyl sulphate proceed in a perfectly straight-forward manner in accordance with equations ( a ) and ( b ) ; practi-cally quantitative yields oE the substituted ammonium methylsulpliates have been obtained without any trouble.EXPERIMENTAL.Preprution of, and Action of Heat on, Anlmonium MethylSulphate.The following method of preparation was found t o give a fairlygood yield of the above salt in a high degree of purity.Theproduct obtained after heating a mixture of 50 grams of puremethyl alcohol and 100 grams of pure sulphuric acid on the water-bath for half-an-hour was cooled and directly neutralised byaddition of powdered commercial ammonium carbonate until, withthe occasional addition of a small quantity of water, a pasty,faintly alkaline mass was obtained; this was extracted with about150 C.C.of boiling methyl alcohol, the cold solution was poured offfrom any ammonium sulphate which separated, and concentratedt o about half the volume by careful distillation. While hot thesolution was again poured off from any substance which hadsep:wated, and on cooling it set to a mass of thin, plate-like crystalswith a satiny lustre. After a further recrystallisation from absolutemethyl alcohol the salt was obtained quite free from even a traceof sulphate, and was almost neutral in reaction; 32 grams of pureammonium methyl sulphate were obtained from 50 grams of methylalcohol.The pure salt melts* a t 1 3 7 O , and is exceedingly hygroscopic; i tis less soluble in ethyl alcohol than in methyl alcohol, hence thepreference of the latter solvent for its purification.In order to study the progress of the isomeric change, a series oftest-tubes containing weighed quantities of the well-dried salt wereheated in a bath of glycerol for fifteen minutes to the desired tem-perature; the bulb of a thermometer, passed through a loosely-fitting cork, was kept immersed in the fused salt during each* When slowly heated the salt may be found to melt at 125', as 9 result of acertain amount of isomeric change.VOL.cv. 8 2766 WERNER : THE ISOMERIC TRANSFORMATION OFexperiment. The product was dissolved in water and titrateddirectly with I?/’-sodium hydroxide, methyl-orangel being used asindicator. On account of the very hygroscopic nature) of the salti t was not advisable to attempt to weigh out a similar quantity foreach experiment; from the equation :NH,*MeSO, = NH,Me*HSO, (M.W.= 129),i t will be readily seen that 1-29 grams of ammonium niethylsulphate would require, after complete isomerisation, 10 C.C. ofW-sodium hydroxide for neutralisation, hence the values for amolecular proportion were calculated from the titration resultsobtained ill the different experiments, and as these numbersexpressed in terrns of percentage of isomeric change are givenunder table I, the full details would be of no particular interest,an1 have therefore been omitted.When ammonium methyl sulphate was heated to about 240°and upwards, a slight evolution of gas commenced after fiveminutes’ heating, and continued very slowly to the end of theexperiment; this was found to be ethylene, the result of asecondary decomposition, namely,2NH4-MeS0, = C,H, + 2NH,HSO,,which to a very slight extent accompanies the main isomeric change.From 20 grams of ammonium methyl sulphatel, after heating underthe most favourable conditions, 8.9 grams of methylamine hydro-chloride were ultimately obtained, corresponding with 85.6 percent.of the theoretical yield for complete isomerisation ; hence thesecondary decomposition referred to above has no serious influenceon the main change.Preparation of, and Action of Heat on, MethylammoniumMethyl Sulpha t e.This salt was readily prepared, in quantitative yield, by passinga current of dry ammonia ‘into a solution of pure methyl sulphatein about fifteen times its volume of benzene until the product, afterkeeping f o r one hour, had a slight odour of ammonia, the flaskcontaining the solution being immersed in ice-cold water.The saltgradually separated in micro-crystalline form ; it was quite colour-less, neutral in reaction, and gave an absolutely negative resultwhen tested with barium chloride solution. The dry salt melts a t5Z0, and is very hygroscopic; its purity was confirmed by analysis,and hence the reaction is correctly represented by the equation:NH, + Me2S0, = NH,Me-MeSO, ;the formation of some ammonium methyl sulphate, recorded bAMMONIUM METHYL SULPHATE, ETC.2767Claessoii nntl T,unclvaal (Lor. ciL.), was probably due to the presemeof some methyl liytlrogen siilphate in the ester nsed by tliein.The esaniiiiation of the progress of the isomeric cliange whenmethylammonium methyl sulphate is heated was carried out exactlyas in the case of the amnioiiiuir. salt; the results so obtained aregiven under table 11.liiferirctioit of -4 nziiies nnd dfutlhyl SiJphnie.The ester used in these experiments was purified from any acidiiiipurities by shaking it with a solution of sodium hydroxide untilneutral; the separated ester was then dried over anhydrous sodiumsulphste, and used directly bithout redistillation.E'rpt. T. A d i n e niid Jfethyl Sulphate (equal molecular propor-tions).-To a solution of 9.3 grams of freshly distilled aniline in75 C.C.of pure benzene, 12.6 grams of methyl sulphate dissolved in25 C.C. of benzene were added; there was very slight developmentof heat, and after a short time, minute, thin, glistening plates begant o separate. After twenty-four hours these were collected, washedwith benzene, and dried over sulphuric acid and afterwards for ashort time in a vacuum. The weight obtained was 21.1 grams,whilst theory requires 21.9 grams if the reaction proceeded inaccordance with the equation :C,H,*NH, + Me,SO, = C,H,*NH2Me*CH3S04.An aqueous solution of the product gave no precipitate withbarium chloride solutlion, and on the addition of bleaching-powdersolution and a few drops of dilute sulphuric szid, a deep indigo-bluecolour was developed,* a reaction characteristic of methylaniline(Found, SO, =44*02.C8H,,04NS requires SO, = 43.83 per cent.).Phenylmethylammonium methyl sulphate melts at 159O, andundergoes isomeric change very readily ; this was strikingly demon-strated in the benzene filtrate from the preparation, which retaineda small quantity of the salt in solution, in the following manner: aportion of the benzene solution was evaporated to dryness on thewater-bath, and the residue gave a copious precipitate with bariumchloride solution, and, on addition of bleaching-powder solution, adeep orange-red colour was a t once developed, a reaction character-istic of dimethylaniline. The original benzene solution when shakenwith dist?ilied water gave no reaction with barium chloride, butwhen previously heated for a few minutes on the water-bath andagain shaken with water, on applying the test reagent a precipitate* It i q generally stated that methylaiiiline gives no colour with bleaching-powder solution, but this is only trne of the free base ; on acidification an intenseindigo-hlue colour is quickly developed.8 s 2768 WERNER : THE ISOMERIC TRSNSFORMATION OFof harimti snlplinte was imine~lintely fornierl as R, resalt; of theisomeric change.The experiment was repeated, using an excess of aniline, andthe weight of crystalline precipitate obtained was practically thesame as before, the excess of aniline being found unchanged in thebenzene filtrate, thus proving that the interaction takes placestrictly in accordance with the equation given above, and that thefailure t o recognise the isomerisation which takes place so readilywas responsible €or t4he erroneous explanation of the change givenby Ullmann (Zoc.cit.).E x p t . ZI. Methylaniline a d Methyl Sulphate (equal molecularproportions).-To 10.7 grams of pure methylaniline dissolved in75 C.C. of benzenel, 12.6 grams of methyl sulphate dissolved in twiceits volume of benzene were added; a clear, pale yellow oil gradu-ally separated, witlhout any appreciable evolution of heat, andafter twenty-four hours this was collected. The weight obtainedwas 32 grams ; the theoretical yield of plienyldimethylammoniummethyl sulphate formd in accordance with the equation :C,H,-NHMe + Me2S0, = C,H,*NHMe2-MeS0,,would be 23.3 grams.The oil when added to water rapidly dis-solved with the separation of some benzene, and any attempt toexpel the latter from the oil by heat was accompanied by evidenceof isomeric change having taken place during the process. Byleaving the oil for a week in a vacuum over sulphuric acid aproduct quite free from benzene was finally obtained. The viscousresidue, which showed no signs of crystallisation, was not analysed,but gave all the reactions of a salt of dimethylaniline, and no otherproduct could be detected in the original benzene separated fromthe oil, the yield of which corresponded very closely with a com-pound of the salt with a molecular proportion of benzene whichwould require 31.1 grams.This property of forming a feeble com-pound with benzene has already been noticed by Claesson andLundvaal (Zoc. cit.) in the case of ethylaniline ethyl sulphate.Expt. IZZ. Dipropylamiue und Methyl Sulphate (equal molecularproportions).-This experiment was carried out as in the previouscase, with 10.1 grams of dipropylamine and 12.6 grams of theester, a clear, almost colourless oil quickly separating with Blightevolution of heat. The yield of oil was 30.8 grams, whilst the theo-retical yield of m&hyldipropylammonium methyl sulphate wouldbe 22.7 grams, and for a compound with one molecular proportionof benzene 30.5 grams. I n this case also an attempt to expelbenzene from the oil by heat was accompanied by isomeric change.The product, freed from benzene by the means mentioned underExpt.11, was a viscous liquid, the aqueous solution of which gavAMMONIUM METHY [, SULPHATE, ETC. 2769no precipitate with barium chloride solution, and on distillationwith pot'assium hydroxide gave methyldipropylamine, which wasidentified by the analysis of its hydrochloride (Found, GI = 23.44.Calc., C1= 23.43 per cent.).Experiments I1 and I11 were repeated, using an excess of therespective amine; in each case this excess was found unchangedin the benzene separated from the precipitated oil, proving thatwith secondary amiiles also the reaction with methyl sulphate isbetween equal molecular proportions and in accordance with thegeneral equations already given.Note 01% ,4mmonium Ethyl Sulphnte and Ammoniumn-Propyl Sulphate.Pure ammonium et'hyl sulphate was readily prepared in verygood yield by directly neutralising crude ethyl sulphuric acid(prepared in the usual manner) with commercial ammonium car-bonate, absolute alcohol being used for the extraction and recrystal-lisation of the ammonium salt.The yield was 58 gram& of thepure compound from 50 grams of ethyl alcohol, no attempt beingmade to recover a further quantity from the mother liquor. Thepure salt crystallises from alcohol in thin, flat, rhomboidal prisms,which have been easily obtained in a length of 4-5 cm., andpossessing a brillia'nt, satin-like lustre.Ammonium ethyl sulphate melts a t 9 7 O (not 6Z0, as stated invarious works of reference), and is not notably hygroscopic, whichis also contrary to the published statements.When heated the salt decomposed rapidly a t about 220° withthe evolution of ethylene; after fifteen minutes a t this temperatarethe amount of decomposition was 55 per cent., in accordance withthe equation :NH4*EtS04= C2H4 + NH4aHS04.No ethylamine could be detected in the residue, thus proving theabsence of ar,y isomeric change.Ammonium iz-propyl sulphate (m. p. 132O) was obtained in gootlyield from crude n-propylsulphuric acid in a manner similar t othat stated above. The pure salt, which is very hygroscopic, decom-posed rapidly a t 150-160° with the evolution of propylene andwithout any evidence of isomeric change.UXIVERSITY CHEMICAL LABORATORY,TRINITY COLLEGR, DUBLIN

ISSN:0368-1645    

DOI:10.1039/CT9140502762

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

2'770 FORSTER AND SCHLAEPFER :CCLIX.-Studies in the Camphane Seeies. Pay-tX X X VI. N- Chloroaminocamphor.By MARTIN ONSLOW FORSTER and MAX SCHLAEPFER.THE subject of this commurication was produced unexpectedly asthe result of attempts to shorten the process for obtaining a-triazo-camphor (camphorylazoimide), the original method (T., 1905, 87,826) being too circuitous far ordinary application.The possibility of replacing the halogen in a-chlorocamphor anda-bromocamphor by heating these materials with sodium azide wasfirst tested, without success, when Raschig's description of a simplemethod for preparing hydrazine (D.R.-P. 198307; A., 1908, ii,1029) suggested the production of camphorylhydrazine, from which,by the action of nitarous acid, camphorylazoimide should arise onthe principle rendered familiar by Curtius.On adding aqueouschloroamine to dissolved aminocamphor, however, a colourless solidwas precipitated, and instead of having the properties to beexpected of camphorylhydrazine, was found to consist of N-chloro-aminocamphor. There remained a possibility of arriving a tcamphorylhydrazine by the action of ammonia on the chloroamine,but experiment showed that the removal of hydrogen chloridetakes place in such a way as to produce iminocamphor, f o r thepreparation of which substance a very convenient method has thusbeen brought t o light:The reaction, in fact, is directly comparable with that by whichiminocamphor was obtained originally :the wrenching away of two atoms-nitrogen alone in the case oftriazocamphor, hydrogen and chlorine in the case of AT-clilnro-aminwamphor-so disturbing the affinity relations of the resid a a 1nitrogen as to cause migration of hydrogen from the neighbouringcarbon.The alternative explanation :iH C1:was tested by the preparation of camphorylacetyl nitrogen chloride(aceto-AT-chloroaminocamphor) and treatment of this conipoundwith ammonia, which Id simply to the regeneration of acetoSTUDIES IN THE CAMPHAKE SERIES. PABT XXXVI. 2771aminocamphor instead of aceto-iminocamphor, or camphorquinoneand acetamide.Although not the first representative of its class, the simplestmember, methylchloroamine, having been prepared in 1893, webelieve that chloroaminocamphor is probably the first materialof this type to be obtained in crystalline form, and, as might beanticipated, it is a very active and unstable substance, oxidisinghydrogen iodide and sulphurous acid in the manner of an acylatedaryl or alkyl nitrogen chloride.It rapidly undergoes a spontane-ous change, the undissolved material being transformed in thecourse of a few hours into a honey-like mass, whilst solutions inhydrocarbons quickly deposit aminocamphor hydrochloride, andcontain t.ha anhydride of cyanolauronic acid together withuncrysiallisable products. I n acetone the chloroamine also changesinto aminocamphor hydrochloride, accompanied by a crystallinecompound (m. p. 155O) having the composition c16Hz30N; this hasnot been identified with any known compound, but the equation :C,,HI6ONC1 + Zc3H60 = HCl + 2H,O + C,,H,,ON,would account for a product having this empirical formula.Whilst ammonia converts chloroaminocamphor into imino-camphor, aromatic amines are oxidised by the substance, whichtakes hydrogen from the amino-group and passes into amino-camphor hydrochloride.Thus aniline yields azobenzene :whilst phenylhydrazine loses its nitrogen.During a few days’ suspension in water, the chloroamine changesinto a crystalline material melting a t 95O, along with amino-camphor hydrochloride. The new compound, which is producedalso when chloroaminocamphor is dissolved in sulphuric acid, islikewise a derivative of nitrogen chloride, and is related to cam-phoric imide, yielding that substance when heated a t looo.Owingto its unstable character, and the consequent difficulty attendinganalysis, we cannot be certain of the empirical formula, althoughCl,Hl6O2NCl,H,O is indicated.EXPERIMENTAL.CH*NHClco N-Chloroaminocamphor, C,Hl,< IAn acid solution of aminocamphor hydrochloride prepared from25 grams of isonitrosocamphor, as already described (T., 1905, 872772 FORSTER AND SCHLAEPFER :113), was chilled with ice and treated with chloroamine from330 C.C. of a sodium hypochlorite solution (containing 32 grams ofavailable chlorine per litre) and 6 C.C. of ammonia (0.88) dilutedto 50 C.C. The solution remained alkaline to litmus, whilst acolourless oil separated immediately and rapidly solidified. Afterthree hours in ice, during which period separation of the chloro-amine was complete, the substance was collected, roughly driedon earthenware, and for all ordinary purposes was used in thisform, 20 grams being the amount usually obtained.As the substance is extremely unstable, purification and analysismust be completed in one day.Such specimens were prepared bymixing the ingredients overnight, leaving the suspended productin the icechest, and filtering early the following morning; theroughly dried material was immersed in cold petroleum (b. p.40-50°) in quantity insufficient for dissolution, and then shakenwith calcium chloride, the amount of which may be gauged t odevelop with thO associated water enough heat to dissolve theexcess of the chloroamine without perceptibly raising the tempera-ture of the solution. This was filtered and rapidly evaporatedunder diminished pressure, when there separated radial aggregatesof colourless needles melting a t 43O and decomposing violentlya t 85O:0.2720 gave 0.6012 CO, and 0.1976 H,O.C = 60.3; H =8*1.0.3042 ,, 18.8 C.C. N, a t 23O and 758 mm. N=7-0.0.2641 contained 0.0442 available chlorine.C,,H,,ONCl requires C = 59.6 ; H = 7.9 ; N = 6.9 ; C1= 17.6 per cent.Chloroainiiiocamphor is sparingly soluble in cold water, but dis-solves very freely in all organic media; it liberates iodine fromaqueous potassium iodide immediately, but before titrating theliquid with sodium thiosulphate it is better to add alcohol and afew drops of glacial acetic acid. Even the purified compoundcannot be preserved, because i t changes in the course of a fewhours to a yellow resin, liberating chlorine and hydrogen chloride;this alteration takes place alike, whether i t is exposed t o the airo r situated in a desiccator containing soda-lime, and occurs alsoif the material is widely and loosely distributed.Although the conditions of preparation appear t o preclude thepossibility of the foregoing substance being the hypochlorite ofaminocamphor, the hydrochloride of the base was mixed in aqueoussolution with sodium hypochlorite alone; this precipitated an oilwhich did not become solid, and which underwent explosive decom-position even while suspended in water.Action of So&um SuZphite.-The simple relation between thechloroamine and the original base is established by the regenera-C1= 16.7STUDIES IN THE CAMPHANE SERIES.PART XXXVI. 2’7’73tion of the latter under the influence of sodium sulphite. Whenfreshly prepared chloroaminocamphor is immersed in a solution ofthe salt, the hard granules rapidly become pasty and afterwardsoily, tho odour of sulphur dioxide being noticeable. With furtherlapse of time the oil disappears, leaving a small proportion ofcamphorquinone , whilst the main bulk of the chloroamine isrepresented in the filtrate by salts of aminocamphor.Decomposition in Benzenw-Solutions of the chloroamine inorganic media change a t various rates, and always yield amino-camphor hydrochloride. Thirty-f our grams of freshly prepared,roughly dried chloroaminocamphor were dissolved in 100 C.C.ofbenzene, dried with calcium chloride, filtered and left in a desic-cator containing soda-lime. I n the course of a few hours amino-camphor hydrochloride began t o separate in colourless needles,increasing with passage of time until about 14 grams had accumu-lated after the lapse of nearly nine weeks; meanwhile the air inthe desiccator liberated iodine from potassium iodide, and thesolution remained active during more than four weeks. On evapor-ating the filtered benzene there was deposited a bright yellow,Iioney-like mass, and although tliis weighed more than 1 2 grams,oiily about 1 gram of cryst.alliiie material was obtained from it.A small proportion of tliis was camphorquinone, separated bykneading the honey successively with small quantities of lightpetroleum, which dissolved that substance ; the residue becamehard and granular, and on being dissolved in a very small quantityof hot methyl alcohol was deposited slowly in colourless crystals,which, on recrystallisation from the same solvent, formed colour-less plates melting a t 1 7 4 O (Found, C-69.3; H=8*3; Nz8.3.C,,H,,O,N, requires C = 69.8 ; H = 8.1 ; N = 8.1 per cent.).Thecompound was thus identified as the anhydride of cyanolauronicacid.The change which chloroaminocarnphor undergoes in petroleumfollows the same course, yielding aminocamphor hydrochloride anda small proportion of the anhydride of cyanolauronic acid.llecomposition in Acetone.-Fifty grams of the chloroaminewere dissolved in 50 C.C.of acetone a t zero, the liquid slowly becom-ing brown. After twelve hours in the ice-chest a heavy, almostcolourless oil had separated, and as this did not, dissolve on adding25 C.C. more acetone the liquid was set aside during one week,when it became homogeneous and much darker, whilst 7.3 gramsof pale brown crystals separated. The filtrate affected the eyes inthe manner of chloroacetone, and did not deposit more solid aftersix weeks a t zero; it was therefore diluted largely with water,which precipitated a brown tar, and from this, by rubbing wit2774 FORSTER AND SCHLAEPFER :cold methyl alcohol, a furt,her 2 grams of crystalline material wasrecovered. On treating the accumulat'ed solid with aqueous alcohol(1: 1), 3.5 grains remained, and the filtrate contained amino-camphor hydrochloride.The solid residue dissolved freely in boil-ing alcohol, and crystallised in lust'rous, very pale brown needles,melting a t 155O:0207G gave 0.5931 CO, and 0-1723 E20.0.1917 ,, 9.9 C.C. N, a t 23O and 763 mm. N=5.8.C,,H,ON requires C = 78.4 ; H = 9.4 ; N =5*7 per cent.The substance is freely soluble in benzene o r ethyl acetate, anddissolves readily in boiling petroleum, from which it is conveni-ently crystallised.Action of A mmonia.-Freshly prepared chloroaminocamphorwas covered with ammonia (0.88) and stirred a t intervals, becomingoily in less than one hour, afterwards changing to a hard cake ofiminocamphor ; as this substance is extremely unstable, and cannotbe recrystallised, it was ident'ified (1) by quantitative conversioninto csmphorqninone and ammonia, and (2) by the characteristicmagenta coloi ation developed with formaldehyde and sodiummethoxide (T., 1908, 93, 250).,4 ction of Amines.-As already stated, the foregoing experimentwas made with the object of preparing camphorylhydrazine, andthe result was totally unexpected.The action of various amineswas therefore studied, but the most definite result was obtainedwith aniline. Nine grams of chloroaminocamphor were dissolved inether, and having been dried with calcium chloride, the solutionwas mixed with 8 grams of aniline. On the following day, 2 gramsof aminocamphor hydrochloride were reiiioved by filtration, andthe dark brown liquid, when freed from ether, was treated withdilute hydrochloric acid to remove excess of aniline.The residualtar became harder when rubbed wit$h a small quantity of alcohol,and having been drained from the latter, was extracted with lightpetroleum, which deposited azobenzene 011 evaporation.When treated under similar conditions with diphenylamine amixture of aminocamphor hydrochloride with ammonium chlorideseparated, and these salts were precipitated also by a-naphthyl-amine, but azonaphthalene could not be identified in the darkbrown, viscous material deposited by the filtrate. With phenyl-hydrazine the action was extremely violent a t the ordinary tem-perature, but on mixing dilute ethereal solutions of the twomaterials at zero very slowly, aminocamphor hydrochloride wasprecipitated and a steady liberation of gas took place.9 ction of Water.-Ten grams of cliloroaminocamphor werecovered with about 30 C.C.of water and stirred a t intervals. AfterC = 78.1 ; H = 9.3STUDIES IN THE CAMPHANE SERIES. PART SXXVI. 2’7’75three days the substance, at first granular and dense, had swolleninto the liquid and had become soft; the following morning it hadbecome dense again and very hard, whilst flat, colourless needleswere suspended in the pale yellow liquid. The solid weighed5 grams, whilst the filtrate, after extraction twice with ether t oremove a very small quantity of camphorquinone, deposited onevaporation 4 grams of axninocamphor hydrochloride mixed witha very small proportion of ammonium chloride.Meanwhile thecolourless crystals, a less inipure form of the hard, granular mass,were found to set free iodine from potassium iodide, and whendissolved in ethyl acetate, using the device already adopted inthe case of chloroaminocamphor, petroleum precipitated flat, colour-less prisms in stellate aggregates. Newly crystallised, the substancemelted a t 95O, evolving gas, but when preserved in a desiccatorcontaining soda-lime, it changed into a material which melted a t2 2 7 O , did not liberate iodine from potassium iodide, and whendissolved in hot water gave the imide of camphoric acid (ni. p.245O); the latter is produced also when the substance is heatedat looo, chlorine being liberated :0.2008 gave0.3887 CO, and 0.1471 H20.0.1822 ,, 9.3 C.C.N, a t 18O and 771.5 mm. N=6*0.0.3460 contained 0.04985 available chlorine. C1= 14.4.C=52*8; H=8*1.C,,H,,O,NCl,H,O requires C =51*1; H = 7.7 ; N = 6.0 ;Cl= 15.0 per cent.We ascribe the indeterminate result of this analysis t o the diffi-culty of removing the last traces of petroleum in a substance,wliich, owing t o its excessive instability, must be analysed immedi-ately. The compound is freely soluble in organic media, but differsfrom chloroaminocaniphor by its sparing solubility in cold petrol-eum. It is also produced when chloroaminocamphor is dissolvedin concentrated sulphuric acid ; 10 grams of the freshly preparedmaterial were added in small quantities t o 50 C.C. of icecold acid,which was shaken vigorously during the process, chlorine beingliberated. After half-an-hour, when effervescence ceased, the liquidwas poured on crushed ice, which precipitated a colourless oil,rapidly solidifying; the product weighed 3.3 grams, and whenrecrystallised from acetone diluted with water formed lustrousneedles melting a t 95O.CH*NCi*CO*C!H,N-Chloronceto-aminocamphor, CI,U,,<~!,The finely powdered acetyl derivative of aminocamphor wassuspended in aqueous sodium bicarbonate a t zero, and treatedwith an ice-cold solution of sodium hypochlorite; after twelvehours the product was filtered, washed, and dissolved in cold methy2’7’16 FRIEND AND MARSHALL : THE CORROSION OF IRON AND ITSalcohol, from which water precipitated lustrous, silky needles,melting a t 7 8 O :0.1500 contained 0*0218 available chlorine.G,,R,80,NCl requires C1= 14.5 per cent.The substance’ is freely soluble in petroleum, acetone, or methylalcohol, and liberates iodine from potassium iodide immediately.Ammonia does not transform it into aceto-iminocamphor, butmerely regenerates the acetyl derivative of aminocamphor.I n conclusion, we desire t o express our thanks to the Managersof the Royal Institution for their courtesy in placing a laboratoryat our disposal.C1= 14.5.TEE DAVY-FARADAY LABORATOI:YOF THE ROYAL INSTITUTION, W

ISSN:0368-1645    

DOI:10.1039/CT9140502770

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

2’7’16 FRIEND AND MARSHALL : THE CORROSION OF IRON AND ITSCCIIX.-l’he CoryosiorL of Iron cind its AppLicutiwto Determine the Relc&v Stwiqths of Acids.By JOHN ALBEI~T NEWTON FRIEND and CHARLES WILLIAMMAR SHALL.IT is now a matbr of common knowledge that fairly concentratedsolutions of sodium hydroxide or carbonate will inhibit the corro-sion of iron. I n 1911 attention was drawn to the fact that thecorrosive action of aqueous solutions or” metallic salts of any con-centration may be completely inhibited by the addition of sufficientalkdine hydroxide (Friend, J . Iroth and Steel Inst., 1911, 111).I n view of the close connexion between corrosion and ionisation itseemed of interestl to determine the minimum quantities of alkalirequired to inhibit the corrosive actions of different salts and todiscover whether or not any relationship exists between these quan-tities and the relative strengths of the acids and bases constitutingthe salts.To this end numerous experiments were carried out by exposingsinall pieces of iron to the action of different salt solutions mixedwith varying quantities of sodium or potassium hydroxide; but theresults were too uncertain and irregular t o be of any value.Thiswas ultimately traced to the presence of carbon dioxide in the air,which was readily absorbed in irregular quantities by the alkalinehydroxides. With the carbonates and borates of the alkali metals,however, very trustworthy results were obtained, capable of exactrepetition an indefinite number of times. Ultimately, therefore,these were used as inhibitors, the carbonates proving the moreconvenient both on account of their simpler constitution and theirgreater solubility in waterAPP1,TCATlON TO DETERMINE RELATIVE STRENGTHS OF ACIDS.27.7 7The procedure was as follows: Five C.C. of ;I N/lO-solution of asodium salt were introduced by means of a pipette into each oneof a series of five hard-glass tubes containing 1, 2, 3, 4, and 5 C.C.of standard sodium carbonate solution respectively. The tubes hadbeen previously steamed out in order to remove any traces ofsoluble matter-a precaution that was found to be absolutelynecessary. The volume of each solution was now made up to10 C.C. by the addition of freshly distilled wates. Finally, pieces ofpure iron foil, measuring 1 cm.square, which had been wellscrubbed with old emery paper and not touched with the fingers,were added, one to each tube, and the latter was sealed with awaxed cork. It was found important to add the iron last of allafter thorough mixing of the solutions employed, as contact withthe different solutions before mixing appeared to exert some influ-ence on the surface of the metal rendering the results uncertain.For the same reason the pieces of iron were never used twice(Friend, T., 1912, 101, 50). The sealed tubes wer0 kept in acupboard a t unifprm temperature, and subject in the daytime toweak, diffused sunlight. After two or three days they wereexamined. The iron in the first one, two, three, or four tubes wasthen usually found t o be corroded, but that in the remaining tubesor tube was not.The tubes could now, as a general rule, be kept for months with-out any further pieces of iron undergoing oxidation.The corrodedmetal in cases distant from the end-point gave signs of furthercorrosion; but those close to the end-point appeared to undergono change. This is remarkable in view of the fact that only asmall fraction of the oxygen in the air in the tubes had beenabsorbed during corrosion. Sulphides yielded a very clear end-point during the first few days, but after prolonged keeping ironsthat had previously shown no tendency to corrode were found tobecome oxidised, thus altering the end-point very considerably.This was ultimately traced t o slow oxidation of the sulphite tosulphate.By repeating tho experiments with intermediate quantities ofcarbonate it was found possible to determine to within about 5 percent. the amount of carbonate required to inhibit corrosion underthe particular conditions of the experiments.The presence of rustwas always easy to detect after a little practice, and it is notimprobable that results of still higher accuracy could be obtainedby the use of more finely graduated instruments.The best method of observation was found to consist in exposingt o a, powerful light, the tubes being continually rotated in orderthat the spots of rust should not be overlooked. These spots wer27’78 FRIEND AND MARSHATAT, : THE CORROSION OF IRON AND ITSoften minute, particularly near the end-points in the case of thestronger acids, frequently occurring a t corners of the inetal iiicontact; with the glass.I n the case of the weaker acids the voliinleof rust produced was, as a general rule, considerably greater,rendering the end-point more easy t o detect.With phos-phates it was white, with an under-layer of green in very dilutesolution. Sulphites gave a green rust, which became red on longkeeping. Chlorides, nitrates, and sulphates yielded reddish-brownrust ; iodides, black.The results obtained with sodium salts, using sodium carbonateas inhibitor, are given in tables I and 11. The concentrations ofthe various salts are expressed in terms of a normal solution, whilstthe amounts of sodium carbonate required t o be present in 10 C.C.of such solutions in order just t o inhibit corrosion are, for the sakeof convenience, expressed both as C.C.of a molecular solution andrelatively t o one another, the highest amount being taken as 100.In actual practice; in the #/lo0 tests, 1 C.C. of a N/lO-solution ofthe salt was taken, varying quantities of the carbonate solutionadded, and the volume made up to 10 C.C. T ~ U S a better comparisonwits obtainable than by making a new solution of the salt.The rust formed varied very much in appearance.TABLE I.Sodium Carbonate asSodium salts, ConcentrationN/20. of Na,CO,.Chloride. ........................... 1-35Iodide .............................. 1.20Bromide ........................... 0.975Nitrate ............................0.725Sulphate ........................... 0-700Fluoride ........................... 0.525Acetate ............................ 0.120Sulphite.. .......................... 0.025Inhibitor.Relativeconcentrationof N+CO,(NaC1=100).10088.972.253.761.8538.98.91.9Relativestrengths offree acids(HC1= 100).1009898987010.5268TABLE 11.Sodium Carbonate as Inhibitor.Sodium salts,NI100.Chloride ............................Iodide ..............................Bromide ...........................Sulphate ...........................Nitrate ............................Fluoride ...........................Acetate ............................Sulphite ............................RelativeconcentratioiiConcentration ofof Na,CO,. Na,CO,.0.526 1000.500 95.20.475 90.50.400 76.20.376 71.40-376 71-40.070 13.30.035 6.7Relativestrengths offree acids inN/lOO-solution.1009897.582.5981748APPLICATION TO bETERMINE RELATIVE STRENGTHS OF ACIDS.2’979Consideration of the above tables reveals the interesting fact thatwhen the salts are arranged in descending order of inhibitingcarbonat’e concectrations, not only are they in the order of thedecreasing electrica1 conductivity of their acids, but the relativequantities of carbonate solution bear a general relationship to thenumerical values found for the strengths of the acids by electricalconductivity and hydrolysis methods.It will also be observed that on increasing the dilution fromN / 2 0 to N/lOO the relative aniounh of the carbonate required bythe different salts steadily approach that required by the sodiunichloride, which is taken as the standard. I n other words, therelative strengths of the acids tand to approach equality withdilution-as the ionic theory requires.It is interesting to note thatin the more dilute solutions the nitrate and sulphate exchangepositions. The low position of the nitrate in the N/20-solution isremarkable, and one is led to ask whether or not passivification hasinfluenced the results, nitrates being well known passivifiers of iron.Still more exceptional are the values found for the sulphite iniV/ZO- and N/lOO-solution. The figures given in the final coluinnsof tables I and 11, however, are based on freezing-point measure-ments, and are therefore less strictly comparable.The results obtained with sodium borate as inhibitor were, onthe whole, very similar. The concentration of the sodium saltswas N/lOO, the’ inhibiting quantities of borax being expressed asC.C.of a molecular solution present in 10 C.C. of the inixed solixtions(see table 111).Concentrat,ion RelativeSodium salts, of concentrationN/100. borax. of borax.Chloride. ........................... 0-36 100Bromide ........................... 0.3 15 87.5Sulphate ........................... 0.3 1 86.1Iodide .............................. 0.33 91.7Nitrate ............................ 0.195 54.2Fluoride ........................... 0.100 27.SAcetate ............................0.070 19.4Sulphite ............................ 0.050 13.9Carbonate ........................ 0.045 12.6Relativestrengths offree acids inN / 100-solution.10097.582.5.089s174830.8”130tThe relatively low solubility of borax in water renders i t lessconvenient ss an inhibitor than sodium carbonate, by restricting* Assnming a dissociation constant Jc= 1.8 x 10W5 (Wdkcr and Corniack, T., 1900,77, 5 ) .t Assuming k=5 x (Thiel and Strohecker)2’780 FRIEND AND MARS€€AT,L : THE CORROSION OF IRON AND ITSthe range of coiiceutrations. When the above resiilh are compare( 1with those in table 11 of like concentration i t will be seen that,a reasonably close similarity obtains. With the exception of theiodide and bromide, which now interchange positions although thedifference between them is very slight, all the other acids retainthe same positions.It is interesting t o note that by this method avalue for carbonic acid is obtainable, which, however, is very high.Thiel and Stlrohecker (Ber., 1914, 47, 945) have recently adducedevidence in favour of the supposition that the true dissociationof carbonic acid is much greater than that usually ascribed to it,since only a small percentage of dissolved carbon dioxide existka ascarbonic acid in aqueous solutions of the gas.Assuming this to be correct, the high value for sodium carbonatein table I11 is readily understood, because practically the whole ofthe carbon dioxide is “ fixed,” and therefore ionised in the solution.Experiments with potassium salts, using potassium carbonate asinhibitor, yielded closely similar results t o those detailed in table I,in so far as the relat’ive quantities of inhibitor were concerned;but the absolute quantities were greater.The concentrations of the potassium salts were N / 2 0 , and intable I V the amount of potassium carbonate required to produceinhibition is expressed as C.C.of a molecular solution in 10 C.C.of the mixed solution.TABLE IV.Potassiitm Carbonate as Inhibitor.RelativeNj20. of K,C03 of K,CO::.Potassium salts, Concentration concentrationChloride ................... 1.85 100Bromide .................. 1.70 92Iodide ..................... 1.70 92Nitrate ................... 0.85 46Sulphate ..................0.775 42Fluoride .................. 0-675 31Acetate ................... 0.225 12Sulphite. .................. 0.050 2.7Relativestrengths offree acids inN/20-solution10097.59897.57010-5258Many salt solutions, such as sodium acetate, borate, carbonate,and sulphide, whilst capable of inhibiting corrosion when fairlyconcentrated, cannot do so if fairly dilute. It was of interest t odetermine accurately the concentrations a t which this auto-inhibi-tion just begins in the case of the above-mentioned salts, in orderto discover whether or not the same ionic relationship holds, as inthe experiments with an added inhibitor. This was accomplishedby immersing small pieces of iron foil in 10 C.C.of varying concen-trations of the different salts, and noting the lowest concentrationAPPLICATION TO DETERMIX E RE1,ATIVE STRENGTHS OF ACIDS. 2781a t which corrosion was pertiianently iiiliibiterl. Tlie results obtainedare given in t,aJJle V.TABLE V.A ut o-inhib i tion.Inhibitingconcentrat,ionof salt.Sodium salt. (i. 1Acetate ............. 0.30 NSulphite ............. 0.06 ,,Arsenate ............ 0-06 ,,I'liospliatc .......... 0- 05 , ,Carbonate ......... 0.02 1 ,,Borate ............. 0.009 ,,Relativeconcentrationofsalt takingacetic acid as8.9 (Table I).(ii.)8.91.81.81.50.62 a. 27Percentage Relativeionisation strengths ofof free acids free acidsat dilutions at dilutionsgiven in given in Col.1Col. 1 at 18". (HCl= 100.)(iii. ) (iv. )0.77 0.5755 5842 4450 530.55 0.570.07 0.07It is not strictly logical to compare column i with column iv,because in the former acetic acid is taken as the standard althoughits concentration is a t least five times as great as that of any otheracid, whereas in column iv _due allowance is made f o r the varyingdegrees of dilution. In the circumstances, however, it is the onlymethod possible, and since weak acids are being dealt with theerror will not be unduly great.It will be observed that the sulphite gives the same r e d t as bythe carbonate method (table I), and the concentration is practicallythe same. The result for sodium carbonate is much lower thanbefore, (table II), and approaches more nearly the usually acceptedvalue for carbonic acid.The difference in the concentrations in thetwo cases (tables I11 and V) is far too small to account for thealteration. The values for the arsenate and phosphate are inkeeping with that for the sulphite, the three free acids beingsimilar in strength according to conductivity measurements. Thelow figures given in table V, however, iudicate that the acids aremuch weaker even than acetic acid, which is not really the case. Onthe other hand, the valus obtained for the borate is four timesgreater than that f o r the free acid. It would appear, therefore,that' these results are not comparable with those obtained by theaddition of inhibitors.Series of experiments have also been carried out with the objectof determining the quantities of sodium carbonate required t$oinhibit corrosion in the presence of varying quantitiee of the sodiumsalts.The' results are given in table VI, the concentrat4ions of thesalts heing expressed in terms of normality, whilst the inhibitingquantities of sodium carbonate in 10 C.C. of the salt solutions are,f o r the sake of convenience, expressed as C.C. of a normal solution.VOL. cv. 8 2782 PEACOCK : ROTATORY POWER AND REFRACTIVITP. PART I.TABLE VI.Sodium salt. N . NJ2. NJ2.5. Nl3.3. Nf4. N/5. N/10. N/17. N/20. N/100.16.0 - - 8.0 - - 2.7 1.05 Chloride . . . . . . .Nitrate ....... 10.0 7.6 5.6 - - 3.6 - - 1.45 0.75Sdphete ...... 4.8 3.2 2.8 - - 2.4 - - 1.40 0.80Fluoride ...... - 1-4 - - 1.4 - 1-4 - 1.05 0.750-O* 0.05 0.07 Sulphite . . . . . . .0.24 0.14 - - - o.o* - - - - Acetate . . . . . . .I -- - - - - - -* Aut~J-inhibition.If these results are plotted diagrammatically a distinct rwem-blance can be traced to the specific conductivity curves of the freeacids when drawn from the data published by Kohlrausch. Unfor-tunately, owing to the limited solubility of the salts employed it isnot possible to employ high concentrations, and thus to pursue theanalogy further. It is interesting t o observe, however, that theacetate curve indicates the existence of a maximum effect,* similarto that observed by Kohlrausch, but a t a different concentration.No attempt is here made to explain these results. The authorswish, a t this stage of their work, merely to draw attention to theinteresting ccmnexion between corrosion and ionisation.In conclusion, the authors have pleasure in expressing theirindebtedness to the Research Fund Committee for a grant that hasdefrayed the greater part of the expense entailed by this work.YICrORIA IKSTITUTE,WORCESTER

ISSN:0368-1645    

DOI:10.1039/CT9140502776

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

2782 PEACOCK : ROTATORY POWER AND REFRACTIVITP. PART I.CCLXL-Rotatory Powe?. and Refractivity. Pa9.t I.The Rotatory Powers, Refiactivities and MoleculaySolution-volumes of Cinchonicine and Boyneol inCertain Solvents.By DAVID HENRY PEACOCK.THE close connexion between the physical expressions deduced onthe electromagnetic theory of light for the optical properties of asubstance has long been noticed. I n practice it is found that sucha molecular structure as is connoted by the term “conjugateddouble bonds ” produces an exaltation of the magnetic and opticalrotatory powers axid of the refractivity. An investigation of therotatory powers, rtfractivities, and molecular solution-volumes wascommenced by the author in order t o discover if there was any* In Koblrausch’s expeiiments the maximum specific conductivity occurred at aconcentration of 2 5 N PEACOCK : ROTATORY POWER AND REFRACTIVITY.PART I. 2783connexion between the two optical properties. While this workwas in progras a series of papers appeared by Livens (Phil. Nag.,1913, [vi], 25, 817 et seq.), in which on theoretical grounds anexpression was deduced connecting refractivity and rotatory power.If n is the refractive index of a solution of density d containing asolut’e in concentration c, then:7ll2 - 1 --- = ?‘C + s(d - c) . . . .a(n2 - 1) + Iniid if [a’] =specific rotation per :Init leiigtli for light of frequeucyg, then :where T and 9” and a. are constants depending on the solute, a i ds is a constant depending on the solvent. Then we have:Tfp%[ Q f ] = 7 (d - 1) ( r 2 - 1 + l/a) 0 .. . L (3)These equations are all given in Livens’ paper. From this lastequation it will be seen that specific rotatory power should vary inthe same manner as the expression ( d - l)(n2- 1 + l/a), No datahave been hitherto available to test this, and in the present paper afew simple cases are considered; the work is still in progress, andmore data are being collected.From the first equation it will be seen that i t should be possibleto calculate the constant, a from the refractivity alone. It is, how-ever, more easily calculated from equation (3). I f we put, c=O inequation (1) then we get:an equation connecting a with the constants of the pure solvent.On the other hand, putting c=lC)O per cent.in (1) we get anexpression for the refractive index of the solute a t 100 per cent.concentration. The quantities can also be deduced from the rotatorypowers, since we have from (3):Therefore if we know the value of [a,] a t a particular concentra-tion c and of m,, the refractive index a t the same concentration,then [a,] or n, a t a concentration x can be found if either is known.I n very dilute solutions it is difficult accurately t o measure [a],and so from the above equation it can be deduced as the refractiveindex is susceptible of careful measurement ; thus trustworthyvalues of [a] a t infinite dilution can be obtained. Similarly, fromthe value of [a] in concentrated solutions the value a t zero dilution8 ~ 2784 PEACOCK: ROTATORY POWER AND REFRACTIVITY.PART I.can be found by extrapolation, and from this the value of ?z underthe same conditions deduced. This quantity may aitain someusefulness, as hitherto the refractive indices of dissolved substanceshave been almost entirely deduced from the additive formula:d nZO - 1d, n2s -I- 2 do nZ0 + 2- --__- M n2 - 1 Jf -I- I n2sq- I - = -__- -~where iK + 1 is the weight of solution containing the gram-molecularweight M of the solute, I is the weight of the solvent of density doand refractive index t h o , and d , and I t , are those quantities f o r thesolvent.From equation (5) it will also be seen that the specific rotatorypower can only be independent of the concentration in cases wheretha refractive index of the solution is independent of the concen-tration ; in other cases there should be variation with concentration,although the amount of this variation cannot at present be pre-dicted.Pope and Gibson (T., 1912, 101, 1702) describe certain deriv-atives of d-ax.-butylamine which show practically no rotatorydispersion. It would be interesting to examine also the refractionconstants of these derivatives in the light of equation (3) givenabove.According to the theory on which the equations given arededuced, the effect' of concentration on specific rotatory power isexplained solely by the variation in the velocity of transmissionof light waves in the solution.When a beam of plane polarisedlight is sglit up on entering an active solution into two beams ofoppositely circularly polarised light travelling a t different velocitiesthe retardation, t o which the rotation of the plane of polarisationis due, is shown by this theory to depend on the optical propertiesof the solvent, and not merely on the active solute.Previoustheories have explained the effects of concentration and of changeof solvent' by (1) electrolytic dissociation, (2) formation of molecularaggregates, and (3) changes in molecular symmetry due to theeft'ect of the internal pressure of the molecule. I n the presentpaper the data are not' very numerous in the cases where a changeof specific rotatory power with concentration occurs, but it may bepointed out that all the above theories ascribe the change toan actual variation of the forces acting within the active molecule,that is t o say, to a change in r' (equation 3). I f , therefore, theeffect of concentration is due t o the above causes, then equation (3)will no longer hold as r' will depend on c, and therefore [a] willnot be proportional to the quantity (122- l ) ( n 2 - 1 + 1 /a).Theresults given in the present communication show that for the solu-tions examined [ a] is, within reasonable limits, proportional t o thPEACOCK: ROTATORY POWER AND REFRACTIVITY. PART I. 8785refraction expression, and therefore in those cases where [a] dependson concentration the dependence is probably not due t o the mole-cular changes usually invoked to explain this dependence, but isdue simply "to the: variation in the velocity of transmission oflight."The rotatory powers of the solutions examined were measured in2-dcm.tabes a t 25O, sodium light being used. The solutions weremade up in 25 C.C. flasks a t 25O. The refractive indices of thesolutions were measured in a Zeiss total reflection refractometer, asis used for examining oils technically. The densities were measuredin pyknometers holding about 10 C.C.Borneol, C,,H,80.This was recrystallised from light petroleum. As also found byVanstone (T., 1909, 95, 600), i t was partly racemised. This doesnot alter the deductions in the present papw, as only ratios ofrota t o.ryP.1.01622.7363.5865-2907.5419.96724.33035.070P1.03022.98055.07309.994015.322powers are dealt with.TABLE I.AlcoJtol Solutions.a".0.275"1.121.462.153.114.1510-6515.70ny.1.36131.36351.36361.36591.36821.37111.38721-3993(156.0.78890.79210.79340.79440.79980.80400.82780.8466[U]':.(27.4') - 1.0915(72; - 1) (%a - 1 +/In).25.8 1.09225-6 1-09325.5 1.09525.7 1.09925.9 1.10226-4 1-11726.4 1.124p=conceiitration in grams per 100 grams.TABLE 11.Acetone Solutions.8 v,n.C.C.[a]%. (Pi - 1) (1L;4- 1 + l / o ) d2 34 .,ZLiD .as60.45" 1.3583 0.7860 158 27.6" - 0.933D '1.26 1.3613 0.7925 160 26.3 0-9342.31 1.3623 0.7960 158 28.6 0.9354.62 1.3675 0.8035 158 25.7 0.9376-73 1.3739 0.8113 159 27.0 0.9418-73 1,3791 0.8184 (175) 27-1 0.943 19.65237.697 17.47 1-4005 0.8493 '159' 27.2 0.942786 PEACOCK : ROTATORY POWER AND REFRACTIVITY. PART 1.&? 5 P.D .0.8699 0.44"2.2461 1.124.433 2-258.951 4.5417.663 9.1826.301 13-72,a 5 P. D *0.9238 0.43'2.3214 1.244.886 2.3611.348 5.78TABLE 111.Ethyl A cetate Solutions.1 L : j . di j. C.C. [a]:. (78; - 1) ( I L 6 - 1 + l / O ? ) .'V*.1.3711 0.8953 161 28.2" -0.9311.3719 0.8956 162 28.4 0.93 11.3761 0.8976 160 28.2 0.9331.3790 0.9004 161 28.1 0.9341.3891 0.9063 160 28.6 0.9371.3983 0.9127 160 28.5 0.938TABLE IV.B e n z e n e Sol& ions.a vnt.1.4995 0.8737 154 (26.6') 4-0.4661.4992 0.8747 159 30.5 0.4641.4985 0.8765 160 29.3 0.4601.4973 0.8813 161 28.8 0.454C.C. [a]:5. (4 -- 1) (92; - 1 + lh]. ,>?. di.5.16.940 8-59 1.4960 0-8864 161 28.6 0.44822.455 11.30 1.4953 0.8909 161 28.2 0.445The solvents used were not specially purified, but were preparedin such quantities that the same salnple could be used throughouta wries of experiments. The benzene and acetone were preparedfrom technical material by drying and fractional distillation.Thefollowing are the constants :TABLE V.Solvent d l i . n2'.Alcohol ........................ 0.7878 1-3602Acetone ........................ 0-7881 1.3571Ethyl acetate ............... 0.8947 1.3701Benzene ........................ 0.8728 1.5004The specific rotatory power of borneol is seen to depend only toa small extent on concentration or solvent; the expression( n 2 - 1)(n2 - 1 + 1 /a), whilst varying with concentration in the Bitmeway as does [a], depends to a very great extent on the solvent; inthe case of benzene which has its refractivity diminished by a solu-tion of bornool the expression has a sign opposite to that for theother solvents examined.Experiments now in progress show thatthis is not a general effect.. Livens (Zoc. cit.) leaves it apparentlyan open question as to the dependence of a on the solvent. Themresults show that n decidedly depends on the nature of the solvent;there is no very apparent connexion between the value of a and therefractivity of the solvent.It is, however, quite well established that for the siinplesb casePEACOCK: ROTATORY POWER AND REFHACTIVITY. PART I. 2787namely, that in which [a] varies very little with concentration, thevalue of (n2 - 1) ( n 2 - 1 + 1 / a ) also shows practically no variation,although over the range of concentrations used the values of n 2 - 1and n2 - 1 In2 + 2 vary considerably.--Cinchomkine.This was prepared according to Miller and Rohde's method (Ber.,1895, 28, 1056).It was purified first by crystallisation of theoxalats from water and then by crystallisation of the base from dryether. Only sufficient was available for a limited examination.TABLE V I .Alcohol Solzctions.C. af".0.1232 0.125'0-6240 0.590.9528 0.902.8900 2.674-4612 4-098.5548 7.699.3000 8.328 13%.71;s. d?"". C.C. [a!:'. (mi - 1) (72: - 1 -i- I / u ) .1.3607 0.7887 75 50.5' -0.4131-3617 0.7910 179 47-3 0.4131.3630 0.7920 222 47.2 0.41 11.3667 0.7984 238 46-2 0.4071-3695 0.8032 243 45.8 0-4041.3796 0.8169 247 44.9 0.3921.3800 0.8186 259 44.2 0.390C.a;6 *0.6160 0.58'2.1136 2.174.1592 4.056.0348 5.928.8712 8.60TABLE VLI.Acetone Solutions.8 vWVn;f". d i e , C.C. [a;']. (ni -- 1) (n: - 1 + lia).1.3579 0.7898 249 56.2' -0.4381.3614 0.7951 244 50.2 0.4351.3662 0.8015 253 48.7 0.4301.3711 0.8100 238 49.0 0-4251.3774 0.8152 260 48.5 0.418c=concentration in grams per 100 C.C.Rques (Compt. rend., 1895, 120, 1170) gives [a]= in alcohol forcinchonicine as 48*25O, but gives no account of a dependence onconcentration. The above results show that in both alcohol andacetone [a] decreases with increasing concentration. I n both cases[a] and (122- 1)(n2- 1 + l l a ) are very closely proportional; thus forthis simple case of dependence on concentration Livens' suggestion,that ths dependence is due simply to the variation in optical proper-ties of thel medium, seems t o be true.If the dependence had beendue to dynamic isomerism or a similar cause then [a] andwould not have varied together as has been explained in theintroduction.(n2- l)(n2- 1 + I / a 2788 PEACOCK : ROTATOKY POWER AND REFRACTIVlTY. PART I.For alcohol solutions the valum of sV,,,, increase with concentra-tion. I f this were a real and not an apparent phenomenon theni t would be expected that the corresponding deformation of themolecule would lead t o considerable variation in [a]; but a deforma-tion of the molecule would lead to a variation in 7" (see equation 3),and [a] and ( tz2 - 1) ( t z 2 - 1 + 1 / a ) would not vary together, whilst inactual experiment they are very closely proportIona1.The varia-tion in S V m is therefore probably, at least in part, fictitious, anddue t o alterations in the volume occupied by the alcohol molecules.Thus by this method $he effect of an active solute on the molecularvolume of a solvent can be at any rate qualitatively examined.Since at present there does not seem to: be any mathematical theoryf o r the mutual effects on density of solvent and solute, this indirectmethod seems the only mode of attack; the theory of solution inthis respect lags far behind the optical theory.,Passing from alcohol t o acetone both [a] and(122-l)(n2-1+l/a)increase.A reference to table X shows that a for these two solu-tions is approximately constant. I n the case of acetone, althoughthe variation of [a] with concentration is as great as that foralcohol solutions, the values of SVm for acetone solutions show nosuch great dependence on concentration.~enzoylci?zchoniciize.Solutions of this substance were examineld in order to see whethera or (n2 - 1) (n2 - 1 + 1 / a ) showed any constitutive effect.c.0.94482.52804.158462128C.0.97042.1028aI,.0.736"1.933-254.86a,.0.88"1.80TABLE VIII.Acetone Solutions.s J7m.? I D . d ? . [a],,. C.C. (n: - 1) (n;", - 1 t l/a).1.3581 0.7916 38.9" 322 -0.8031.3623 0.7973 (38.2) 322 0-8041.3651 0-8033 39.1 322 0.8041.3726 0.8102 39.2 325 0.806TABLE IX.L41cohol Solutions.s I.',.77 1).dt6. [a],. C . C . (?lt - 1) (n; - 1 +- lh).1.3621 0.7911 45.3" 329 -0.9321.3647 0.7984 42.8 320 0.88PEACOCK : ROTATORY POWER AND REFRACTIVITY. PART I. 2789TABLE X.Values of a for the Solutions Examined.Substance. Solvent.Cinchonicine ............ Alcohol9 ) ............ AcetoneBenzoylcinchonicine ... Alcohol1 9 ... AcetoneBorneo1 .................. AlcoholAcetoneEthyl acetateBenzenea.- 0.747-0.733- 1.036- 0.557- 0.468-0.513-0.615- 1.1411 /a.- 1.337- 1.363- 0.964- 1.795-2.132- 1.948- 1.938- 0.876Beiizoylcinchoiiicine shows a decrease in both [a] and(d- l)(nz- 1 + l/a)on passing from alcohol to acetone, the reverse of 'the case forcinchonicine.There is no very apparent constitutive connexionbetween the value of n o r (n.2- l)(n2- 1 + l / a ) for cinchonicine andits benzoyl derivative ; both of these quantities depend too greatlyon the nature of the solvent. However, the results obtained withthe acetone solutions confirm the interdependence of [a] and(722- 1 ) ( d - 1 + 1 /a). I n passing from alcohol to acetone the valuesof [a] for benzoylcinchonicine decrease considerably, whilst thevalues of ,V, show no very great variation.For the cases examined in the present paper confirmation hasbeen obtained of the theory that where variations in [a] occur theyare due to variations in the velocity of transmission of light withinthe medium, and not t o causes directly affecting the degree ofasymnletry of the molecule. It has, furthermore, been shown howevidence can be obtained as to the effect of a solute on the densityof a solvent.Further work is in progress on these lines, and with the addi-tional object of obtaining a value for the refractivity of an activesolute.I n conclusion, the author wishes to express his thanks to theNobel's Explosive Company, Ardeer Factory, and t'o Mr. W.Rintoul, F.I.C., Manager of the research section, for the facilitiesafforded f o r carrying out this work and permission t o publish theresults.THE RESEARCH SECTION,NOBEL'S EXPLOSIVES COMPA~ Y,A RDEKI

ISSN:0368-1645    

DOI:10.1039/CT9140502782

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

2790 HARDING : SUBSTITUTION INpounds. PLwt 11. Acetyl-nit vo-sdstitut ion.By VICTOR JOHN HARDING.BY the term acetyl-nitro-substitution is meant the displacement ofan acetyl group by a nitro-group. This displacement can be effectedby the action of nitric acid on certain methoxyacetophenones, andi t is believed to be direct, without the formation of any inter-mediate hydrogen-substituted compound. So far as i t has beenstudied, it is dependent on the, presence of methoxy-groups in thebenzene nucldns and on the position of the acetyl group. It is notthought, however, that acetyl-nitro-substitution differs fundament-ally from the substituticn of a hydrogen atom by the nitro-group(hydrogen-nitro-substitution), methoxy-groups merely enabling thenucleus to be more readily nitrated and thus giving an opportunityfor the less mobile acetyl group to bo substituted more easily thanwould otherwise have been the case.The only instance in the literature of acetyl-nitro-substitution isthe observation of Harding and Weizmann (T., 1910, 97, 1131),who found that 4 : 5-dimethoxy-o-tolyl methyl ketone very readilygave 4-nitrohomocatechol dimethyl ether when treated with nitricacid :OM0 0 MeThe displacement of the aldehyde group by the nitro-group(formyl-nitro-substitution) in aromatic methoxy-aldehydes, however,had been studied by Sslway (!I!., 1909, 95, 1155), who drew theconclusion t'hat the displacement was direct.The analogous case oE the displacement of a carboxyl group by anitro-group (carboxyl-nitro-substitat-ion) was discussed in the first ofthis series of communications (T., 1911, 99, 1585).From a numberof examples and the author's own experimental work, it wasdeduced that:(a) The substitution was direct, without the intermediate forma-tion of the parent phenol ether.( b ) The substitution took place only when the carboxyl groupoccupied a position which in the parent phenol ether was activetowards nitric acid.The present communicatiori, which deals with acetyl-nitro-substiAROMATIC IIYDROXY-COMPOUNDS, PART 11. 2791tution, is a study of the action of nitric acid on a series of metlioxyacetophenones.(a) p-Me th oxyace tophenone, OMw C,H,*COMe.The action of nitric acid on this ketone was first studied byGatterinann, Ehrhardt, and Maisch (Ber., 1890, 23, 1202).Theuse of a mixture of concentrated sulphuric acid and nitric acidresulted in the formation of di-4-methoxybenzoylf uroxan (dianisoyl-glyoxime peroxide) :OMe*C6H4* GO* 7~~OMe*C,H,*CO'C 2'On the other hand, Pope (P., 1912, 28, 331) obtained the normalnitration product, 3-nitro4-methoxyacetophenone.The latter result the author has confirmed, but by using nitricacid alone has obtained on two occasions the furoxan and a t othertimes the nitro-ketone.Acetyl-nitro-substitution does not take place in pmethoxyaceto-phenone, and Salway (Zoc. cit.) failed to find any formyl-nitro-substitution during the nitration of anisaldehyde. The nitration ofanisic acid, however, by a mixture of warm concentrated sulphuricand nitric acids results in carboxyl-nitro-substitution, a mixture of2 : 6-dinitroanisic acid and 2 : 4-dinitroanisole being obtained :OMe Ohlo OMe(compare Cahours, A nizalen, 1849, 69, 236).(b) 3 : 4-Di?nethoxyacetophenone.The action of nitric acid 011 this ketone does not appear to havebeen studied previously. I n the cold o r in warm glacial acetic acidsolution, acetyl-nitro-substitution takes place very readily with theformation of 4 : 5-dinitroveratrole :OMe(c) 3 : 4 : 5-Tri?,i~tl~osyncetoI,heno?i~.This ketone has previously been prepared by Maubhrier ( J .p.Chem., 1910, [ii], 82, 275) by tvhe action of diazomethane on gall-aldehyde trirnetliyl ether, arid by the acid hydrolysis of ethy27 92 HABDIXG : SUBSTITUTION IN3 : 4 : 5-trimethoxybenzoylacetate. The melting point, as stated byMauthner, is 7 2 O .Bogert and Isham (J. Amer. Ghem. Soc., 1914,36, 514) repeated the preparation from ethyl 3 : 4 : 5-trimethoxy-bmzoylacetate, and gave t'he melting point as 78O. The author hasprepared this ketone, however, by the following series of reactions:OMe OMe 031e0Mf)OMe z' OMr()Ol\la\/'CO-NH,\/COCl\/CO,HOMe OMe-+ PClB OMe/)OMe\/CNhleMg1--3 OMe().OJleA C\/The preparation of gallamide trimethyl ether has been describedin a previous paper (Harding, T., 1911, 99, 1593), and its con-version into the nitrile is easily effected by the use of phosphoruspentachloride in hot benzene solution. Up t'o this point the yieldsare excellent, butj the conversion of gallonitrilel trimethyl ether into3 : 4 : 5-trimetEioxyacetophenoiie does not proceed as smoothly andin as good a yield as might be expected from analogous reactions.Large amounts of a nitrogenous substance are produced, whichpossesses the empirical constitution C,,H,,O,N,, is soluble in sodiumcarbonate solution, and gives rise t o an insoluble potassium saltwhen treated with 50 per cent.aqueous potassium hydroxide. Theketone is formed only in small amount&, and is separated from theunchanged nitrile by taking advantage of the insolubility of thelatter in cold dry ether. 3 : 4 : 5-Trimethoxyacetophenone crystal-lises from light petroleum in needle@, melting a t 77-79O, and givesa piperonylidene derivative melting at 130-131O.The action of nitric acid on this ketone was as expected fromits analogy t o gallic acid trimethyl ether and myristicinaldehyde.Acetyl-nitro-substitution takes place very readily, and 5-nitropyro-gallol trimethyl ether is produced.Moreover, the substitution is adirect, one, f o r had there been the1 formation of intermediateproducts in any recognisable amount, such as gallic acid trimethylether from the oxidation of the ketone or pyrogallol trimethylether from its hydrolysis, tho occurrence of these compounds wouldhave become evident by the finding in the nitration product ofnitrogallic acid trimethyl ether or 2 : 6-dimethoxybenzoquinone(Part I).Neither of these two compounds was found, although both areeasily identified, and thus it is believed that the acetyl-nitro-substi-tution is directAEOMATIC HYDROXY-COMPOUNDS.PART IT. 2793(d) 2 : 3 : 4-Ts.imethoxya.cetophetio~~e.This well-known ketone has always been prepared by tlie methyla-tion of 2-hydroxy-3 : 4-dimetl-toxyacetoplienone (Perkin and Wilson,T., 1903, 83, 129; David and Kostanecki, Ber., 1903, 36, 2191;Bulow and Schmid, Ber., 190G, 39, 214). Unsuccessful attemptswere made to prepare i t directly from the condensation of acetylchloride and pyrogallol trimethyl ether through the agency ofaluminium chloride. Even although the reaction was only allowedto proceed a couple of hours and the temperature kept a t Oo, theproduct of the reaction was always the hydroxy-ketone, the methylgroup in position 3 being hydrolysed.Using ferric chloride, how-ever, as a condensing agent, partial success was attained.2 : 3 : 4-Trimethoxyacetophenone was produced, although only insmall amount, and its identity established by means of itspiperonylidene derivative.The action of cold concentrated nitric acid on 2 : 3 : 4-trimethoxy-acetophenone gives rise to 6-nitro-2 : 3 : 4-trimethoxyacetophenone :0 5.38 OMeThe positJon 6, and not 5, is assigned t o the nitro-group from theanalogous reactions of nit'ric acid on pyrogallolcarboxylic acid tri-methyl ether (Harding, T., 1911, 99, 1585) and on its methyl ester(Pollak and Goldstein, Animlen, 1907, 351, 161).The nitro-ketone, however, was isolated only as its piperonylidenederivative, and even that proved extremely difficult, and it iseasily conceived that in the oily nitration mixture which wasobtained, 4-nitropyrogallol trimethyl ether might have existed andits presence remained undetected.I n this way evidence of acetyl-nitro-substitution might have been overlooked. I n order to throwfurther light on this point, 2 : 3 : 4-trimethoxyacetophenone wassubmitted to the vigorous action of warm nitric acid. I f any4-nitropyrogallol trimethyl ether had been produced in the lessvigorous nitration i t would certainly have shown itself in the moreextended action as 4 : 5-dinitropyrogallol trimethyl ether (compareThoms and Siebeling, Ber., 1911, 44, 2115). No 4 : 5-dinitropyro-gallol trimethyl ether was found, and the only product isolatedfrom the vigorous nitration of 2 : 3 : 4-trimethoxyacetophenme wasa compound which from its elementary analysis corresponded withdi-6-nitro-2 : 3 : 4-trimethoxybenzoylfuroxan 2794 HARDING : SUBSTITUTION INThus i t will bo seen that the evidence is quite against the occur-rence of 4-nitropyrogallol trimethyl ether iii the oily nitrationproduct of 2 : 3 : 4-trimethoxyacetophenone.Acetyl-nitro-substitn-tion does not take place when the acetyl group occupie8 position 4in pyrogallol trimethyl ether. I n this way acetyl-nitro-substitutionis quite analogous t o carboxyl-nitro-substitution. I n neither casedoes the substitution take place except when the acetyl or carboxylgroup occupies a position which is active towards nitric acid inthe parent phenol ether. The distribution of forces set up by themethoxy-groups determines the position entered by the nitro-groupwhether the group previously attacked be hydrogen, acetyl, orcarboxyI.The corresponding case for the aldehyde group has n o tyet been experimentally determined, although the author has nodoubt that it will be found t o follow the same rule.l n the next communication, which will follow shortly, an accountwill he given of a series of experiments on the' action of nitric acidon a number of polymethoxy-derivatives of benzene in the presenceof carbamide and of hydrogen peroxide.EXPERIMENTAL.Action of Nitric dcid 078 ~ - i ~ ~ e t l ~ o x ? / a c e t o p ~ e r z o ~ z e .Five grams of pinethoxyacetophenone were dissolved in 20 C.C.of concentrated nitric acid and allowed t o remain overnight.Onpouring into water an oily solid separated, which soon hardened,and on being submitted t o a process of fractional crystallisationfrom alcohol proved t o be entirely 3-nitro-4-methoxyacetophenone.No mono- or di-nitroanisole was found (Pope, P., 1912, 28, 331).In another experiment in which the time of reaction was onlyfifteen minutes much unchanged ketone was recovered, and a smallamount of di-pmethoxybenzoylf uroxaii was isolated. The lattercompound was identified by its melting point and analysis. Theformation of any nitro-ketone was not observed, although the wholeof the recovered p-methoxyac&ophenone was converted into itspiperonylideiie derivative and fractionally crystallised.3-Nitro-km ethoxyphenyl 3 : 4-Me thgle nedioxystyryl He tone,CH,<~>C,H,- CH : c H.co C,H,(NOJ OM^.This unsaturated ketone is readily obhined by condensing3-nitro-4-methoxyacetophenone snd piperonal in alcoholic solutionby a trace of potassium hydroxide. The ketone separates instantlyfrom the alcoholic solution, and is pnrified by crystallisation fromglacial acetic acid, from which it separates in needles melting a XROMATIC HTDROXT-CON POUNDS. PART 11. 2795194O. Its solution in concentrated sulphuric acid is reddish-purple :0.1301 gave 0.2979 CO, and 0.0501 H,O. C = 62.4; H =4*2.Ci7Hl,0,N requires C = 62.4 ; H = 4.0 per cent.d ctiolb of iVitric Acid o n 3 : 4-Dinzetl~oxyncetophenone. Formationof 4 : 5-Dinitroveratrole.One grain of 3 : 4-diniethoxyacetoplienone was dissolved in 10 C.C.of concentrated nitric acid, and the reaction kept under control by2 stream of running water.A t the end of ten minutes the productwas poured into water, 2nd the yellow solid which separated wascollected and purified by crystallisation from alcohol. It crystal-lised in bright yellow needles, melting a t 131--132O, and wasfound to be identical with 4 : 5-dinitroveratrole.One gram of 3 :4-dimetlioxyacetophenone was dissolved in 10 C.C.of glacial acetic acid, 2 C.C. of concentrated nitric acid were added,and the solution was warmed. A vigorous reaction occurred, andwhen this had subsided the product was cooled and poure'd intowater, when 4 : 5-dinitroveratrole separated and was easily identified.0MeThis nitrile has previously been described by Heffter and Capell-mann (Ber., 1905, 38, 3634), who obtained i t by heating togethera mixture of gallic acid trimethyl ether and lead thiocyanate.It has also been described by Semmler (Ber., 1908, 41, 1918),who prepared it by boiling oxiiiiinogallaldehyde trimethyl ether forhalf-an-hour with acetic anhydride.The melting point' is given as9 5 O by Heffter and Capellmann and 93O by Semmler. Gallonitriletrimethyl ether is very readily and conveniently prepared fromgallamide trimethyl ether (Harding, T., 1911, 99, 1593) by theaction of phosphorus pentachloride. The two substances weremixed in equimolecular amounts in the presence of a little benzene,and heated together for a couple of hours in boiling water.Thebenzene and phosphoryl chloride were then removed by distillationunder diminished pressure. Any attempt, however, t o distil thenitrile a t this stage resulted in decomposition, and therefore theproduct was partly purified by crystallisation from aqueous alcohol.The nitzile was then distilled under diminished pressure, andfinally purified by crystallisat ion from methyl alcohol. The mdtingpoint was found t o be 9 3 O , and the yield 70 per cent. (Found,N = 7.2. CIOHliOSN requires N = 7.2 per cent.)2796 SIARDING : SITRSTITUTION 1N3 : 4 : 5-Trimetlzoxyacetophe?~o1ze, o~s(\ONle.\/AcThree grams of magnesium and 15 grams of methyl iodide' wereconverted into magnesium methyl iodide in ethereal solution. Thegreater part of the ether was removed by distillation, and an equalamount of benzene added.A solution of gallonitrile trimethylether (20 grams) in benzene was then added, and the reactionallowed to continue for eighteen hours on a gently-heated water-bath. The yellow, insoluble product was decomposed by ice anddilute hydrochloric acid. More ether was added, and the aqueoussolution extracted with a further quantity of ether. The combinedethereal extracts were washed with water, dilute sodium carbonatesolution, and dilute aqueous pot'assium hydroxide in turn. Thesodium carbonate washings were reserved (p. 2799). The etherealextract was finally washed with dilute hydrochloric acid, dried,evaporated, and the residual oil fractionated under diminishedpressure. The fractions of higher boiling point which becamepartly solid were then triturated two o r three times with pure dryether. This dissolved the ketone and a small amount of oil, leavingthe nitrile, which is almost insoluble in pure dry ether.Theethereal solution was filtered and evaporated, when the residual oilcrystallised on keeping. The ketone crystallised from light petrol-eum in needles melting a t 77-79O (Found, C=62*6; H=6*8.Calc., C=62*8; I3=6.6 per cent.).3 : 4 : 5-(rrimethoxyphetzyl 3 : 4-Methylenedioxystyryl Ketone,This derivative is prepared in an exactly similar manner to theisomeric 2 : 3 : 4-trimethoxyphenyl 3 : 4-methylenedioxystyryl ketone(p. 2797). It crystallises from alcohol in bright yellow needles,melting a t 130-131°, and dissolves in concentrated sulphuric acidwith a reddish-violet coloration :0.1179 gavel 0.2907 CO, and 0.0583 H,O.C=67*3; H=5*5.C,,H,,O, requires C = 66.6 ; H = 5.5 per cent.An oily phenylhydrazone, C,,H,O,N,, was obtained by the con-densation of 3 : 4 : 5-trimetlioxyacetophenone and phenylhydrazinein acetic acid solutionAROMATIC HE'DROST-C'OMPOUNDS. PART 11. 2797Action of Nitric A cid on 3 : 4 : 5-T9.i,iietlhozyacct~~~~~en~~nti :Formataoih of 5-NitmpgrognlloE Trimet hyE E' t her.Half a gram of the ketone was dissolved in 2 C.C. of warmglacial acetic acid, and 0.5 C.C. of concentrated nitric acid added.There was an instantaneous reaction, and the product was heatedon the water-bath until the copious evolution of nitrous fumes hadceased.On cooling and pouring into water, 5-nitropyrogalloltrimethyl ether was precipitated, and was readily identified byits crystalline form (from :tlcohol) and its melting point. Whenmixed with a specimen of 5-nitropyrogallol trimethyl ether preparedfrom pyrogallol trimethyl ether the melting point remainedunaltcred.OMt!Fifteen grams of pyrogallol trimethyl ether and 9 grams ofacetyl chloride were dissolved in carbon disulphide, 15 grams ofanhydrous ferric chloride added, and the reaction was allowed tocontinue overnight. The black product was decomposed by ice anddilute hydrochloric acid, the carbon disulphide removed by distilla-tion in a current of steam, and the residual, dark-coloured, oilysolid ext'racted by means of ether. The ethereal extract was washedwith diluto potassium hydroxide, which removed much 2-hydroxy-3 : 4-dimethoxyacetophenone, dried, and distilled, when an oil boil-ing a t 295-297O passed over.This was identified by analysis(Found, C = 62.7 ; H = 6.6 ; C,,H,,O, requires C = 62.8 ; H = 6.6 percent.) and by its piperonylidene derivative as 2 : 3 : 4-trimethoxy-acet op henone.2 : 3 : 4-Trimethoxyphenyl 3 : 4 - 1 N e t ~ y l e n e d i o x y ~ t ~ r y ~ Ketone,This derivative was prepared by mixing equimolecular amountsof piperonal and 2 : 3 : 4-trimethoxyacetophenone in alcoholic solu-tion, and condensing them by means of a few drops of 50 per cent.aqueous potassium hydroxide and boiling. Thel product was cooled,a little water added, and the piperonylidene compound separat'edout as an oily solid, which rapidly hazdened. It crystallises froinalcohol in stout needles, melting a t 101-102°, and dissolves inconcentrated sulphuric acid with a deep red colour:0.1188 gave 0.2953 CO, and 0.0594 H,O.C=66*9; H=5*5.VOT,. CV. 8lJC,,H,,O, requires C = 66.6 ; H = 5.5 per cent2798 HARDING : SUBSTITUTION INThe same piperonylidene derivative is obtained by the condensa-tion of piperonal wilh 2 : 3 : 4-trimethoxyacetophenone preparedeither by the direct condensation of acetyl chloride and pyrogalloltrimethyl ether through the agency of ferric chloride (see above)or by the methylation of 2-hydroxy-3 : 4-dimethoxyacetophenone(compare Perkin and Wilson, T., 1903, 83, 129).Action of Nitric Acid o n 2 : 3 : 4-Trimethoxyacetophettotie.(a) Formation o f 6( !)-Nitro-2 : 3 : 4-trimethoxyucetopherio?te,OMeTwo grams of 2 : 3 : 4-trimethoxyacetophenone were dissolved inconcentrated nitric acid, and the solution was kept cold for fifteenminutes by immersion in running water.There was no violentreaction, and a t the end of that time the solution was diluted withmuch water, when a heavy oil separated, which did not solidify onkeeping. I n order to determine whether this oil consisted chieflyof unchanged 2 : 3 : 4-trimethoxyacetophenone or a nitro-ketone, i twas converted into its piperonylidene derivative. The oil wasextracted by means of ether, the ethereal solution washed withdilute) sodium carbonate solution, dried, and evaporated. Theresidual oil was dissolved in boiling alcohol, a considerable excessof piperonal added, and a few drops of aqueous potassium hydr-oxide.Condensation took place' readily, the piperonylidene com-pound separating as a red oil, which could not be obtained in asolid condition. The1 alcoholic solution was diluted with water, andthe whole of the red oil which separated was extracted by meansof ether. The ethereal solution was then washed several timeswith a concentrated solution of sodium hydrogen sulphite t o removethe excess of piperonal, dried, and evaporated. This residual oilwas almost insoluble in cold alcohol, but dissolved readily in theboiling solvent, which, on cooling, deposited the piperonylidenecompound as an oil. By exposure t o a temperature of about -15Ofor more than a week, however, the oil solidified, and a pale yellowsolid was obtained, which crystallised from alcohol and melted at96-97O to a deep yellow liquid.The almost colourless crystals,however, always contained some of a deep yellow colour, but afterseveral crystallisations the whole changed into a deep yellow modi-fication. This melted a t 11 1-1 1 2 O , dissolved in concentratedsulphuric acid with a reddish-yellow colour, and evidently conAROMATIC HYDROXY-COMPOUNDS. PART 11. 2799sided of 6-nitxo-2 : 3 : 4-tririiertlioxypliellyl 3 : 4-metl~ylenecliosystyrylketone :0.1188 gave 0.2541 CO, and 0.0432 H20. C = 58.4 ; H = 4.0.0.1749 ,, 7-2 C.C. N, (moist) a t 25O and 758 mm. N=4*5.C,,HI7O,N requires C = 58.9 ; H = 4.3 ; N = 3.6 per cent.(b) Formotion of Di-6-nitro-2 : 3 : 4-trimethoxybenzoyIficroxan,NO,*C',H(OMe),*CO CN O,*C,H( ORle),-CO*C ' >N,O,.This action of hot concentrated nitric acid on 2 : 3 : 4-trimethoxy-acetophenone was investigated in the hope that acetyl substitutionwould occur, and as a result that 4: 5-dinitropyrogallol trimethylether would he isolated.One gram of 2 : 3 : 4-trimethoxyaceto-phenone was dissolved in concentrated nitric acid and the solutionboiled until the vigorous reaction, which had set in, ceased. Theproduct was dilut'ed with water, when a slightly oily solid wasprecipitated. The water was decanted, and on adding alcohol theproduct became completely solid. It was collected and purified bycrystallisation from benzene, from which it separated in small,faintly yellow needles :0.1217 gave 0.2098 CO, and 0.0413 H20. C=47*0; H2-3.7.C22H,,01,N, requires C = 46.9 ; H = 3.5 per cent.Bi-6-dro-2 : 3 : 4-trimethoxyb enzoylfwoxnn is insoluble in water,alcohol, or dilute sodium carbonate, but dissolves in hot aceticacid.No 4 : 5-dinitropyrogallol trimethyl ether was isolated fromthe mother liquors.Isolutioi~ of u Compound, CslHn07N2, from the Actioii ofMagnesium Methyl Iodide o n Gallonitrile T'nirnethgl E'ther (p. 2795).The sodium carbonate washings from the Grignard reaction(p. 2796) were evaporated on the water-bath for a short time toremove ths ether, cooled, and 50 per cent. aqueous potassiumhydroxide was added until no more precipitate appeared. The pre-cipitated potassium salt was collected, suspended in warm water,and decomposed by dilute hydrochloric acid, when an oil wasprecipitated which solidified on cooling. The solid was collectedand purified by crystallisation from benzene, from which i tseparated in sniall prisms melting a t 125-126O:0.1236 gave0.2773 CO, and 0.0564 H20. C?=61.1; H=5.1.0.2280 required 11.6 C.C. il'/lO-H,SO,.C21H2,07N2 requires C = 60.9 ; H = 5.3 ; N = 6.7 per cent.C2,H,,@7N, ,, C=61.1; H=4*9; N=6.8 ,, ,,* Other analyses gave C=61'2 ; H=5*2 ; N=6*5.N = 6*6.*8 u 2800 LE SUEUR AND WITHERS: THE MECHANISMIt, was found that, a cleterininntion of tthe hasicity of the8 acid hytitration witli normal alkali gave untrustworthy results, the end-point with phenolplithalein being extremely indefinite.I n conclusim, I desire to thank the Research Fund Committeeof the Chemical Societ\y for the grant which has defrayed part oft h e cost of this investigation.MCGILL ~ ~ N l V l C l X 3 l * ~ Y ,~fOXrREA1,

ISSN:0368-1645    

DOI:10.1039/CT9140502790

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

2800 LE SUEUR AND WITHERS: THE MECHANISMCCLXII1.-The Mechanism of the Action of FusedAlkalis. Part I. The Action of Fused PotassiumHydroxide o n Dihydroxystea& Acid andDihyclrozy behenic Acid.By HENRY RONDEL LE SUEUR and JOHN CHARLES WITHERS.ONE of the stages in a method f o r the determination of the consti-tution of fatty acids (Crossley and Le Sueur, T., 1899, 75, 161;1900, 76, 83) consists in the oxidation of the dihydroxy-derivativeof the acid under investigation by means of chromic acid, and itwas pointed out a t the time that when dealing with a higher fattyacid the insolubility of its hydroxylated derivative might renderthis oxidation a difficult operation. It was thought that fusion ofthe hydroxylatsd derivative with potassium hydroxide mightreplace the oxidation with chromic acid, and in order to investi-gate this point one of us (Le Sueur, T., 1901, 79, 1313) fuseddihydroxyst earic acid with potassium hydroxide in the hope t'hatoxidation would take place thus:CH,*[C&],*CH(OH)*CH(OH)*[CH,],*CO,H +The results obtained, however, were quite different, and it wasshown that the main product) of the action was a monohydroxy-dicasboxylic acid o i the formula CI8H3,O5.The present investiga-tion deals with the constitution of this acid and also of a similaracid obtained by the fusion of dihydroxybehenic acid with potassiumhydroxide.When the acid C,8H3405 is oxidised with potassium permanganatein acetone solution i t is quantitatively converted into a ketomono-carboxylic acid having the formula C17H3203; and when it is heatedCH3*[ CH& C0,H + C O,H* [ CH,],*CO,HOF THE ACTION OF FUSED ALKALIS.PART I. 2801aIone and above its melting point, it readily loses water and twoisomeric unsaturated dicarboxylic acids, C,,H,,O,, are produced.These facts led us t o suppose that the acid ClSH3,O5 was aP-hydroxy-acid having the constitutionCO,H*CH,* CH (OH). [CH,] 14*C02H.Such an acid would give on oxidation the ketonic acid,C02H*CH2*CO*[CH,],,*C02H (I),and the latter would readily lose carbon dioxide t o give the acid,CH3*CO*[CH,]14*C0,H. Although the free acid (I) possibly couldnot be isolated, one would expect that its ethyl ester would besufficiently stable t o admit of this being done. We accordinglytreated the ethyl ester of the acid, C,,HsO,, with oxidising agents,but in spite of a large number of experiments we were unable t oobtain the desired est'er; either no oxidation took place o r if it didthen carbon dioxide was lost simultaneously, and the acid C,,Ha03was produced.We then decided to determine the constitution ofthis ketonic a i d , and for this purpose it was treated with hydroxyl-amine, and the resulting oxime converted into the correspondingamides by heating with concentrated sulphuric acid, and theseamides were hydrolysed by heating with hydrochloric acid. Theproducts of the hydrolysis were identified as n-nonoic acid, octyl-amine, azelaic acid, and 7-amino-izroetoic acid. From this itfollows that the ketonic group is in the middle of the chain, andthat the above products are formed as follows:NH OH CH,*[CH,],*CO*[CH,],*CO,H --?+CH,*[CH,]7*C(NOH)*[CH,]7*C0,HThe' position of t2he carbonyl group and, of course, of the CH-OHgroup wliicli gives rises to it, having been established, it nowremained t o determine the position of the carboxyl group which iseliminated in the formation of the ketonic acid by the oxidationof the acid C18Ha05.It was natural to suppose hhat it was a t th2802 LE SUEUR AND WITHERS: THE MECHANISMend of the chain, and that the constitution of the acid CI8H3,O5was CO2H*~CH2],-CH(OR)*[CH2],-CO,H. The loss of water whensuch an acid is heated and of carbon dioxide when i t is oxidisedare difficult to explain, and this difficulty led us t o investigate itfurther.It has been stated already that when the acid C,,H,O, is heatedabove its melting point i t readily loses water t o give the unsaturatedacids C,,H3,04, and on submitting these to oxidation so as t o breakthe chain the following acids were obtained : n-octoic, n-nonoic,suberic, and azelaic.The occurrence of azelaic acid in the oxida-tion products shows that the group -C-[CH,],*C* is present in theparent acid, and the formation of 92-nonoic acid under like condi-tions is evidence that the group CH,*[CH,],*C* is also present.These results point to the conclusion that one of the carboxylgroups is near the middle of the chain, and this is supported by thefact that when the unsaturated acids formed by the loss of waterfrom the acid C,8H3405 are reduced with hydrogen in the presenceof platinum black a saturated dicarboxylic acid, C,,H,O,, meltinga t 71*5-'72*5O, is obtained, whereas the normal dicarboxylic acid,CO,H*[CH,],,-CO,H, melts a t 1 1 8 O .This and other considerationsled us t o the conclusion that one of the carboxyl groups and thehydroxyl group were attached to one and the same carbon atom,and that the acid C18H3405 was a-hydroxy-a-octylsebacic acid,CH3*[CH,]7*C(OH)(C0,H)*[CH,],*C0,H. This was proved to becorrect beyond all doubt by the actual synthesis of the acid bymeans of the hydrogen cyanide method thus :CH,I CH,I CH3 I[ICH,'I7 y 3 2 1 7 LC;'H,I,LOCf.'B& IHCN C(OH}.CN -3 HzO C(OH)*COzH----f I I I[ I1 21 7I["'2I7C0,H GO,H C02HThe syiitlietic acid had all t'he properties of the original acid ;thus when oxidised with potassium permanganate i t gave theketonic acid C17H3203, melting a t 78*5O, and when heated it readilylost water t o give a producb which readily reduced potassiumpermanganate, etc.The identification of n-octoic acid, n-nonoic acid, suberic acid,aiid azelaic acid as tlie products of the oxidation by potassiumpermanganate of the unsaturated acids produced by the removal oftlie elements of water by lieat from a-hydroxy-a-octylsebacic acidsliows that this loss takes place in two directions thusOF THE ACTION OF FUSED ALKALIS.PART I. 2803--+The product of the fusion of dihydroxystearic acid with potass-ium hydroxide also contains small quantities of a second acid,which we find to be identical in all respects with the ketonic acid,C17H3203, melting a t 78*5O, and produced by the oxidation of theacid C18H3,05 with potassium permanganate.That the occurrenceof this ketonic acid amongst the products of the fusion is due t othe further oxidation of the acid C18H,05 is proved by the factthat it is formed when the acid C18H305 itself is fused withpotassium hydroxide.I n the previous communication (T., 1901, 79, 1313) dealing withthe fusion of dihydroxystearic acid with potassium hydroxide theformula C18H3,03 was erroneously assigned to this second acidfound amongst the products of the fusion. This error is easilyaccounted for when one remembers that the amount of this acidobtained a t that time was small, and that there is only a smalldifference between the percentages of carbon and hydrogen requiredby the formulae Cl,H%O, and C17H3203.I n order to see how far this remarkable reaction was general wecarried out a similar investigation of the action of fused potassiumhydroxide on dihydroxybehenic acid, and find that the reaction inthis case is exactly analogous to that with dihydroxystearic acid.Dihydroxybehenic acid, obt'ained by the oxidation of erucic acidwith potassium permanganate in alkaline solution, when fusedwith potassium hydroxide is converted into the monohydroxy-dicarboxylic acid, C22H4205, which on oxidation with potassiumpermanganate loses carbon dioxide, and yields the ketonic acid,C,,H,,,03. The constitution of this ketonic acid has been deter2804 LE SUEUR AND WITHERS: THE MECHANISMmined, and the parent acid synthesised from it by the hydrogencyanide method.These various changes are tabulated below :CsH17*CH:CH[ CH2]11*C02H -4 RMnOFusion C*H,,*CH(OH)*CH(OH)*[CH,],,*CO,H zt=2KMnOA.HCN + hydrolysis,C (OH) (COZH) [ CH,], 1 CO2H t-- -+NH2OH.C,H,,*CO*[CH,I,,*CO,H ~ +C,H,;.C(NOH)*[CH2],*C02H 1 H280~The product of the fusion of dihydroxybehenic acid with potass-ium hydruxidel also contains small quantities of the, ketonic acidC,H4,0,, which is undoubtedly formed by the oxidation of theacid C22H42O5 by the fused potassium hydroxide.The above intramolecular changes which take place during thefusion with potassium hydroxide are of particular interest as theyinvolve the migration of the heavy group C8HI7* from one carbona.tom to another adjacent to it.It is probable that this changeprecedes oxidation, and that an acid containing a primary alcoholgroup is formed as an intermediate product. I f this assumption isgranted, then the formation of the dicarboxylic acid is easilyexplained, for it has beeln shown that. primary alcohols readilyvield acids when they are fused with potassium hydroxide (Guerbet,Compt. rend., 1911, 153, 1487; 1912, 154, 222, 713) OF THE ACTION OF FUSED ALKALIS. PART 1. 2805With the object of obtaining direct evidence as to the correctnessof the above supposition we fused dihydroxystearic acid withpotassium hydroxide in an atmosphere of nitrogen, and in thisway hoped to limit the reaction to the intramolecular change.I nthis, however, we were not successful, as the product under theseconditions is also the acid CI8HMO5, the yield of acid being thesame in both cases. This result is nevertheless interesting as itshows that the oxidation' occurring during the fusion is notdependent on tlhe presence of atmospheric oxygen.We have been unable to find any record of the move'ment of sucha heavy group within the molecule of an aliphatic compound. Asomewhat analogous case in the aromatic series is the formatioiiof benzilic acid by the action of fused potassium hydroxide onb e n d and by the action of aqueous potassium hydroxide and airon benzoin.EXPERIMENTAL.Prepration of a-Hpdroxy-a-octylse back A cia?,CO,H*C(OH) ( C8HI7) [CH,],* C0,H.This acid was obtained by the fusion of dihydroxystearic acidwith potassium hydroxide, and the method employed did not diffelrin any essential detail from that described in a previous communi-cation (Le Sueur, T., 1901, 79, 1317), except that the acidobtained by acidifying the aqueous solution of the fusion wasdissolved in ether, the ethereal solution dried and evaporated, andthe residue crystallised from a mixture of benzene and chloroform.The yield of pure acid melting a t 1 1 1 - 1 1 2 O was very constant,and amounted t o 65 per cent.of the theoretical.The b e w o y l derivative, CO,H~C(OBZ)(C,H,~)~[CH,]~*CO,H, wasprepared by the Schotten-Baumann method, in the hope of obtain-ing a solid derivative which would serve to characterise the parentacid.Unfortunately, i t proved t o be a glassy mass, which couldnot be purified:0.2309 gave 0.5776 CO, and 0-1838 H,O. C=68'22; H=8*91.0.3439 required 15.9 C.C. O*lN-NaOH. M.W. = 432.6.C25HB06 requires C = 69.08 ; H = 8-82 per cent.The m-nitrobenzoyl derivative,M.W. = 434.3.C02H*C(O*CO* C,H,-NO,) (C,H,,) [CH2I7* CO,H,was prepared from the acid and nz-nitrobenzoyl chloride by theSchotten-Baumann method. The product was a viscid mass, which,after treatnient with dilute hydrochloric acid, was freed fromnitrobenzoic acid by boiling with water. The insoluble residue wascrystallised, first from dilute formic acid and then from a mixtureof chloroform and light petroleum, from which i t separatee as 2806 T,E SUEUR AND WITHERS: THE MECHANISMwhit,e powder melting a t 80-81O.eum, and soluble in chloroform or glacial formic acid :It is insoluble in light petrol-0-2078 gave 5.4 C.C.N, a t 22O and 755 mm. N=2*91.C,,H,,O,N requires N = 2-92 per cent.Prepmation of 8-Xetomargaric Acid, C,H,,*CO*[CH,],*C02H.Ten grams of a-hydroxy-a-octylsebacic acid were mixed with160 C.C. of acetone (previously purified by treatment with potassiumperrnanganate) and 20 C.C. of water, and the mixture was gentlywarmed with powdered potassium permanganate, which was gradu-ally added. After t'he addition of 8 grams of permanganate, theoxidation proceeded very slowly. The acetone was then removed bydistillation, the residue treated with water, and the manganesedioxide dissolved by dilute sulphuric acid and sulphur dioxide.The precipitated acid was dissolved in ether, the ethereal solutionwashed, dried, evaporated, and the residue crystallised from amixture of chloroform and light petroleum.The yield was 79.5 percent. of the theoretical:0.1560 gave 0.4098 CO, and 0.1578 H20. C=71*64; H=11*32.*0.3766 required 13.6 C.C. 0-W-NaOH. M.W. =277.C,,H,,O, requires C = 71.77 ; H = 11.35 per cent. M.W. = 284.3.8-Xetomargaric acid, C,H,7*COo[CH,],*C0,H, is readily solublein cold chloroform and moderately so in ether, alcohol, ethylacetate, or benzene in the cold. It is insoluble in light petroleum,and crystallises from a mixture of this solvent and chloroform inglistening plates melting a t 78'5O.It is not oxidised by an alkalinesolution of potassium permanganate in the cold. The acid is alsoproduced by the fusion with potassium hydroxide of a-hydroxy-a-octylsebacic acid. The white silver salt was obtained on addinga warm alcoholic solution of the sodium salt of the acid t o a warmalcoholic solution of silver nitrate :0.2784 gave 0.0784 Ag. Ag=28*16.C,,H,,O,Ag requires Ag = 27.60 per cent.Hethy1 8-ke tomargara t e , C,H,7*CO*[CH,],*C02Me, was obtainedby heating for four and a-half hours on the water-bath a mixtureof 8.5 grams of the acid, 90 C.C. of methyl alcohol, and 45 C.C. ofconcentrat'ed sulphuric acid. The product was poured into water,the est'er dissolved in ether, the ethereal solution dried, evaporated,and the residue crystallised from methyl alcohol, from which i tseparates in large, pearly flakes, melting a t 45.5O:0.1518 gave 0.4030 CO, and 0.1585 H,O.C=72*40; H=lI:68.C,,H,O, requires C = 72.42 ; H = 11.49 per cent.* A second analysis gave C: = $1 $9 ; H = 11.40OF THE ACTION OF FUSED ALKALIS. PART I. 2807h't h yl 6-ke to margar ate, C8H,,*CO* [ CH2],*C0,Et, was preparedby the method used for the preparation of the methyl ester, andwas purified by crystallisation from dilute alcohol, from which itseparates in pearly flakes melting a t 38O. It is readily soluble inalcohol, benzene, chloroform, or acetone in the cold :0*1109 gave 0.2964 CO, and 0.1172 H20. C=72.89; H=11.83.Cl,H3,O3 requires C = 73-01 ; H= 11.62 per cent.8-Ketomargaramide, C,H,,.CO*[CH,],*CO*NH,, was preparedthus: 1.2 Grams of the ketonic acid and 0.8 gram of thionylchloride were heated together on the water-bath for half-an-hour,and the cold product was poured into excess of ammonia. Theprecipitated amide was dissolved in ether, the solution washed,dried, and evaporated, and the residue crystallised from a mixtureof chloroform and light petroleum, when i t was obtained in irides-cent needles melting a t 119O.It is insoluble in light petroleum,and dissolves in alcohol, chloroform, ether, benzene, or hot water :0*1100 gave 4.6 C.C. N, a t 21° and 762 mm. N=4.75.CI7H,,O,N requires N = 4.95 per cent.8-lietu?ncrr~~raniZ~de, C8H,,*CO*[CH,],*CO-NHPh, was obtaiiieclby the action of the acid chloride (prepared by the interaction ofthe acid and thionyl chloride) on aniline.It was purified bycrystallisation, first from acetic acid and then from formic acid,and was obtained as a white, crystalline powder, melting a t 96.5O.It dissolves freely in alcohol, acetone, chloroform, or benzene, issparingly soluble in ether, acetic acid, or formic acid in the cold,and insoluble in light petroleum :0-2925 gave 9.9 C.C. N, a t 19O and 770 mm. N=3*95.C,,H,,O,N requires N = 3.90 per cent.The semicarbasone of 6-ketomargaric acid was obtained by heat-ing for five hours on the water-bath an aqueous-alcoholic solutionof 0.6 gram of the acid, 0.5 gram of semicarbazide hydrochloride,and 0.5 grain of dry potassium acetate, and was purified by crystal-lisation from acetone, from which i t separates in stellar aggregatesof prisms melting a t 1 1 1 O .It is sparingly soluble in alcohol,acetone, or ethyl acetate in the cold, and is insoluble in ether orlight petroleum :0.1206 gave 13.1 C.C. N2 a t 19O and 774 mm. N=12.55.The oxime of 0-ketomargaric acid was prepared by boiling on thewater-bath for three hours a solution of 5 grams of the acid,2 grams of liydroxylainine hydrochloride, and 3 grams of sodiumhydroxide in a mixture of 40 C.C. of alcohol and 20 C.C. of water.The alcohol was then evaporated, and the product poured intoC,,H,,O,N, requires N = 12.31 per cent2808 LE SUEUR AND WlTHERS: THE MECHANISMdilute sulphuric acid, when the precipitated oil was extracted withether. The ethereal solution was washed with water, dried, andevaporated.The residue was a colourless oil, which did not solidifyeven on leaving in a vacuum desiccator for three months:0.2618 gave 9.8 C.C. N, a t 15O and 750 rnm. N=4*30.C,,H,,O,N requires N =4.68 per centt.Conversion of the Oxime of 0-Ketomaryaric Acid into the AmidesCsH,7*CO*NH*[CH2]7*C0,H am2 CsH,,*NH*CO*[CH,]7-C0,H.The oxime (8 grams) was slowly poured into concentrated sul-phuric acid (40 c.c.) and the solution heated for one and a-halfhours on the water-bath. The resulting dark brown liquid wascooled and slowly poured on crushed ice, and the precipitatedamides were collected and crystallised from dilube acetic acid, fromwhich they separated in aggregates of thin plates melting a t68.5-69.5O. Although the substance thus isolated is undoubtedlya mixture of two amides, its melting pointl is nevertheless quitesharp :0.2450 gave 10.4 C.C.N, a t 17.5O an1 758 mm. N=4*90.C,,H,O,N requires N = 4-68 per cent.Hydrolysis of the above Amides.-2-5 Grams of the amides wereheated with 12 C.C. of concentrated hydrochloric acid in a sealedtube a t 180° for four hours. The dark brown products resultingfrom several such quantities were mixed with water and distilledin a current of steam (distillate=A). The residue was then madealkaline1 and again distilled in steam (distillate = B). The residuewas now concentrated t'o a sman bulk, and poured into excess ofconcentrated hydrochloric acid, and the mixture left for some time,when a crystalline solid separated (solid = C), which was relmovedby filtration (filtrate = D)IDistillate B was extracted several times with much ether, theethereal solution washed tlwice with small quantities of water,dried, and evaporated.The residue obtained from 21 grams oftho mixed amides weighed 4.8 grams, and all distilled bebween248" and 255O; it was purified by fractional distillation, and theportion boiling at 251-253O collected for analysis. This fractionreadily solidified on cooling in ice, and the resulting solid meltedat 1 2 - 1 3 O :0.3420 required 21.6 C.C. 0-1N-NaOH. M.W. = 158.4.n-Nonoic acid, C9H180.,, lias M.W. = 158, b. p. 253.4O (corr.), andni. p. 12*Go. The identity of the acid with n-nonoic acid wasfurther proved by converting a small quantity of it inta its zinOF T E ~ E ACTION OF FUSED ALKALTS.PART T. 2809salt, wliicli, after crystallisation froni absolute alcohol, melted a t1 3 4 O , which is the melting point of zinc 1,-nonoate.Distillate B.-This alkaline distillate was acidified with hydro-chloric acid, the resulting solution mixed with much ether in aseparating funnel, and then made strongly alkaline with potassiumhydroxide, and the whole quickly shaken. This procedure wasadopted in order t o enable tlie ether t o dissolve the base before thelatter had had time t o combine with the water t o form a hydrate.The dried ethereal solution on evaporation gave a residue whichdistilled between 173O and 177O. A small quantity of this wasconverted into the platinichloride, which wits analysed (Found,Pt= 29.15.[C8Hl7*NH2,HCI],Ptc1, requires Pt = 29.31 percent.).The free base gave tlie carbylamine reaction, and readilyabsorbed carbon dioxide from the air. It is therefore identicalwith octylamine, the boiling point of which is 175-177O.s-PI~enyZoct?lZcarbamide, C,H,,*NH*CO*NHPh, was prepared byadding 0.4 gram (1 mol.) of phenylcarbimide to 0.4 gram (1 mol.)of the above base, dissolved in 10 C.C. of dry benzene, and allowingthe mixture to remain overnight. The solution was then concen-trated t o half its bulk, and mixed with light, petroleum. Thecarbamide which separated was dissolved in a mixture of benzeneand light petroleum, from which it crystallises in flakes, meltingat 80°. It is readily soluble in alcohol, chloroform, or benzene,and is insoluble in light petroleum :0.1808 gave 17.4 C.C.N, a t 19O and 776 mm. N=11.32.C,,H,,QN2 requires N = 11.29 per cent.Solid C.-This consisted of long, flat needles, melting at105*5-106*5°, which, after crystallisation from water, were quitecolourless and melted a t 106.5O. The acid had the characteristicappearance of azelaic acid (m. p. 106O), with which it is un-doubtedly identical (Found, C =57'40; H =8*75. M.W. = 189.6.CnHIGOi requires C = 57.40 ; H = 8-58 per cent. M.W. = 188).Filtrate D.-This, which contained much free hydrochloric acid,was e'vaporated t o dryness, the residue partly dried, and thenrepeatedly extracted with acetone. This acetone solution on eva-poration left a residue which was dissolved in hot alcohol, and theresulting solution was mixed with an equal volume of ether.Fromthe mixture the1 hydrochloride of the amino-acid was depositedgradually in glistening needles melting a t 145-146O. (The hydro-chloride of q-amino-n-octoic acid melts a t 147O). (Found, N = 7.10.C8HI70,N,HC1 requires N=7*16 per cent.) A small quantity ofthe) hydrochloride was converted into the platinichloride (Found,Pt = 26-60. Calc., Pt = 26-80 per cent.)2810 I,E SUEUR AND WITHERS : THE MECEIANISMThe amino-acid resulting from the hyclrolysis of t h e mixed miidesis, therefore, q-amino-n-octoic acid.The yields of the' four substances obtained by the hydrolysis ofthe mixed amides were as follows:12-Nonoic acid .................................... S5.4 per cent.of the theoreticalOctylamine ....................................... 86.5 ,, 5 9 9 ,Azelaic acid ....................................... 83.0 ,, 9 9 3 7Hydrochloride of 7-amino-x-octoic acid ... 67.0 ,, 9 9 9 9Formation of the Ui~saturated Acids, C,,H,,O,, from a-llydroxg-a-octglsebacic Acid.Eight grams of a-hydroxy-a-octylsebacic acid were graduallyheated under a pressure of 25 mm. in a distilling flask immersedin a metal-bath. Effervescence, due to the evolution of water-vapour, began a t about 220°, and rapidly increased as the tempera-ture rose. The vapour evolved contained only a trace of carbondioxide. The temperature was maintained a t about 280° until alleffervescence had ceased, and then raised gradually, when theliquid distilled between 290° and 310° and gave 6.8 grams ofdistillate.This was redistilled under 30 mm. pressure, and aportion boiling a t 294-295O collected for analysis :0.1624 gave 0.4152 CO, and 0.1520 Q O . C= 69.72 ; H = 10.34.A specinien from another preparation was converted into the0.2168 gave 0.0870 Ag. Ag=40*13.C,8H300,Ag, requires Ag = 41.02 per cent.The above figures agree sufficiently with the calculated values toshow that the substance is produced from a-hydroxy-a-octylsebacicacid by the loss of water only. It was kept for several months,but could not be obtained as a definite solid; also, redistillationunder diminished pressure produced slight decomposition. Theelimination of w a t a from a-hydroxy-a-octylsebacic acid by Iieat-big it with sulphuric acid was also tried.F o r this purpose, theacid was heated a t 200-220° for four and a-half hours with 60 percent. sulpliuric acid in a sealed tube. Much sulphur dioxide wasevolved when the tube was opened, and the contents were foundto consist for the most part of 8-ketomargaric acid, melting at78.5O. I n other words, the sulphuric acid had acted as an ordinaryoxidising agent. I n another experiment, the acid was boiled withdilute sulphuric acid for two hours, but$ in this case, the acidwas recovered unchanged.That the substance produced by heating a-hydroxy-a-octyl-C,,H,O, -requires @= 69.23 ; H = 10.258 per cent.silver sal* and analysedOh' THE ACTION OF FUSED ALT<AT,IS. PART I. 2811sebacic acid is unsaturated is confirmed by the facts that i t readilyreduces potassium permanganate in alkaline solution in the cold,and, under the influence of platinum black, absorbs hydrogen togive the saturated dicarboxylic acid, C18H304, described onpage 2812.Its constitution was determined by investigating theproducts obtained when it is oxidised by potassium permanganate,as described below. Two quantities of 11 grams each of the acidwere dissolved in a mixture of 170 C.C. of acetone and 20 C.C. ofwater, and to this, finely powdered potassium permanganate wasadded. Reduction took place immediately in the cold, and becamevery energetic on warming. Small quantities of permanganatewere added from time to time to the boiling solution until themwas no further reduction.The acetone was then distilled off, themanganese dioxide dissolved by means of dilute sulphuric acidand sulphur dioxide, and the whole distilled in a current of steam(distillate=X). The mother liquor in the flask deposited, on cool-ing, a solid (9 grams), which was collected and dissolved in 250 C.C.of boiling wat'er. This solution deposited, on cooling, a solid(2 grains), which was removed by filtration (filtrate= P), and thenredissolved in hot water. The solution was neutralised with excessof magnesium carbonate and filtered while hot. The filtrate wasconcentrated to a syrup, allowed to cool, and the magnesium salt,which had separated was collected. It was again crystallised fromwater, and finally decomposed by heating with dilute hydrochloricacid.The acid thus obtairied was crystallised from water, fromwhich i t separated in large, thin, glistening plates, melting a t105-106O. A mixture of equal parts of this acid and azelaicacid (m. p. 106O) melted a t 106O. (Found: M,W.=187*8.CgHl,O4 requires M.W. 188.)Filtrate Y was evaporated to dryness, and the dried residue,melting a t 90--126O, was exhracted four times with ether, using12 C.C. for each extraction. The undissolved residue melted a t137-140°, and, after crystallisation from water, melted a t 138.5O.(Found : C = 55.02 ; H = 8.20. M.W. = 174.6. C8H1,0, requiresC=55*14; H=8*10 per cent. M.W.=174.1.)The substance was thus proved t o be suberic acid.Distillate X was extracted with much ether, the ethereal solu-tion washed once with water, dried, and evaporated, and the resi-due was fractionally distilled.The fraction boiling at 234-242Owas identified by analysis as woctoic acid (b. p. 236-237O).(Found : M.W. = 142 ; Ag =43*35. C,H,,02 requires M.W. = 144,and f o r silver salt Ag=42.98 per cent.)The fraction boiling at above 245O (Found: M.W.=158.C9HI80, requires M.W. = 158) was converted, through th281 2 LE STTEUR A S T ) WITHERS : THE MECHAKISMsodium salt,, into the zinc salt, wliicli was shown to be zincu-nonoate. The amount of substance dealt with did not admit ofa complete separation and isolation in a pure state of the u-octoicand n-nonoic acids, but the analysis showed that these two acidswere undoubtedly present in the mixture.Prepamtion of a-Octylsehncic Acid, C0,H*CH(C,H,7)fCH2]7~C0,H,by Reduction of the Unsaturated Acids, C18H3204.This reduction was effected by the direct addition of hydrogenin the presence of spongy platinum.The catalyst was prepared bythe reduction of platinic chloride by means of formaldehyde inthe presence of sodium hydroxide (Loew, Ber., 1890, 23, 289;Willstiitter, Ber., 1912, 45, 1472; IIess, Ber., 1913, 46, 3120),and was washed first with water and then with glacial acetic acid.Five grams of the unsaturated acids CI8H3,O4, dissolved in 10 C.C.of glacial acetic acid, were reduced. The absorption of thehydrogen was never very rapid, the quickest rate being about50 C.C. in twenty minutes. Sometimes the hydrogen was under apressure of about 20 cm. of :mercury above the atmosphericpressure, but this did not appear to increase the rate of absorption.When no further reduction took place, the acetic acid solutionwas warmed, filtered, and the filtrate poured into water.The pre-cipitated acid was collected and crystallised from a mixture ofchloroform and light petroleum until its melting point was con-stant. The yield was 70 per cent. of the theoretical:0.1350 gave 0.3405 CO, and 0.1350 H,O. C = 68.79 ; H = 11-19.0.2054 required 13'2 C.C. 0-1N-NaOH.a-Octylsebacic acid, C02H*CH(C8H,7)*[CH2]7*C0,H, cryshllisesfrom a mixture of chloroform and light petroleum in aggregatesof hard prisms, melting a t 71'5-72'5°. It is readily soluble inalcohol, chloroform, o r ether in the cold, sparingly so in coldbenzene, and insoluble in light petroleum.It does not reduce analkaline solution of potassium permanganate even when heated,nor does it decolorise a solutJon of bromine in chloroform. Thewhite silver salt was obtained on adding a solution of the sodiumsalt of the acid t o a solution of silver nitrate:M.W. = 311.2.C,,H,O, requires C = 68.75 ; H= 10.90 per cent. M.W. = 314.25.0.1540 gave 0.0622 Ag. Ag=40*39.C18H3,0,Ag2 requires Ag = 40.86 per cent.Uet 12. yl a-oct ylsebacat e, CO,Me*CH ( C8H17) *[CH,],*CO,Me, wasprepared by the interaction of the dry silver salt of the acid andmethyl iodide in solution in dry benzene. It is an oily liquidOF THE ACTION OF FUSED ALKALIS. PART I. 2813boiling a t 230-233O/25 mm., and dissolves readily in the commonorganic solvents :0.1580 gave 0.4054 CO, and 0.1636 H,O.0.3056 in 15.7840 benzene gave At - 0.307O.CmH,04 requires C=70.11; H=11*19 per cent.The diamide , NH,* CO*CH( C8EI7) *[ CH,], CO*NH,.-One gramof the acid and 0.5 C.C.of thionyl chloride were warmed togetheron the water-bath for fifteen minutes, the product was dissolvedin ether, and the ethereal solution poured into a concentrated,aqueous solution of ammonia. The precipitated amide was col-lected, washed with water, and crystallised from dilute alcohol,from which it separates in slender needle,s, melting a t 167-168O.It is insoluble in water, ether, benzene, or chloroform in the cold,and dissolves re'adily in boiling alcohol :C=69.98; H=11*59.M.W. = 322.M.W.=342.0.1990 gave 15.6 C.C.N, a t 20° and 754 mm. N=8.92.C,,H,O,N, requires N = 8.97 per cent.Synthesis of a-Hydroxy-a-octylsebacic Acid from 8-HetomargaricA cid.Ten grams of pure, dry hydrogen cyanide and six drops oftriethylamine were added to a solution of 10 grams of 6-keto-margaric acid in 50 C.C. of dry chloroform. After remaining fora fortnight in a well-stoppered bottle, kept in a cool place, thechloroform and excess of hydrogen cyanide were evaporated bymeans of a current of air, and the solid residue was dissolved inether, the ethereal solutlion washed with dilute sulphuric acid,then with water, dried, and evaporated. The residue was hydro-lysed by dissolving i t in SO C.C. of alcohol, previously saturatedwith dry hydrogen chloride.The mixture was left a t the ordinarytemperature f o r three and a-half days, and then boiled on thewater-bath for eight hours. The resulting solution, on cooling,deposited 24 grams of crystalline solid, melting a t 38-39O, whichwas found to be the ethyl ester of the unchanged ketomargaricacid (see page 2807). This was removed by filtration, the filtrateevaporated to dryness, and the residue boiled for forty hourswith 24 grams of potassium hydroxide dissolved in a mixture of50 C.C. of alcohol and 10 C.C. of water. The complete hydrolysisof the hydroxy-cyanidel was difficult to effect, and, even after boil-ing for the period mentioned, traces of ammonia were still beingevolved. The alcohol was evaporated, the, residue diluted withwater, and extracted with ether.The aqueous mother liquor wasthen poured into dilute hydrochloric acid, the precipitated aciddissolved in ether, the ethereal solution washed, dried, andVOL, cv. 8 2814 LE SUEUR AND WITHERS: THE MECHANISMevaporated. The residue weighed 7.5 grams, and, after three re-crystallisations from chloroform, melted a t 11 1-1 12O. A mixtureof equal parts of this acid and a-hydroxy-a-octylsebacic acid melteda t exactly the same, temperature:0.1371 gave 0.3270 CO, and 0.1286 H,O.0.2254 required 13.5 C.C. O'lN-NaOH.The synthetic acid, like the original a-hydroxy-a-octylsebacicacid, readily loses water when heated, to give a liquid which veryreadily reduces potassium permanganate. When oxidised withpotassium permanganate in acetone solution, the synthetic acidgives a monobasic acid melting a t 78*79O, identical with the8-ketomargaric acid obtained by the oxidation of a-hydroxy-a-octyl-sebacic acid.This identity was fully confirmed by the fact thata mixture of equal parts of the two acids melted a t 78-79O, andfurther, the methyl ester of the ketonic acid obtained from thesynthetic acid had all the properties of methyl 6-ketomargarate.C = 65.05 ; H= 10.50.M.W. = 330.3.M.W. = 333.9.C,,H,,O, requires C= 65.40; H,=10*38 pelr cent.Preparation of Dihydroxybehenic Acid.The method employed for the oxidation of erucic acid differedsomewhat from that used by Hazura and Grussner (Monatsh.,1888, 9, 948), and since t'hew observers obtained a yield of only25 per cent.of the theoretical, whereas ours amounted to 75 percent., we give the essential details of the method we used. Thirty-five grams of crucic acid (m. p. 33O) and 14 grams of potassiumhydroxide were dissolved i n 2 litres of water, the solution cooledto Oo, and maintained a t this temperature during the whole ofthe oxidation. A solution of 32 grams of potassium permanganatein 1500 C.C. of water was then added drop by drop to the solu-tion, which was kept well stirred by means of a turbine. Themixture 'was allowed to remain over night, the manganese dioxidedissolved by means of dilute sulphuric acid and sulphur dioxide,and the precipitated acid filtered and crystallised from alcohol.Preparation of a-Hydroxy-a-oc tyldodecanedicar boxylic A cid,C02H*C(OH)(C,H,7)*[CH2]11*COeH.Twenty grains of dihydroxybehenic acid (m.p. 127-128O), 100grams of potassium hydroxide, and 40 C.C. of water were mixedtogether in p nickel crucibles, and the whole' gradually heated ina metal-bath to 240-245O, and maintained a t this temperature forone hour, the fused mass being stirred continuously. The coldmass was dissolved in water, acidified with dilute sulphuric acid,and the precipitated acid dissolved in ether. The ethereal 601~OF THE ACTION OF FUSED ALKALIS. PART I. 2815tion was washed, dried, evaporated, and the residue crystallisedonce from chloroform and then from acetone until its meltingpoint, was constant. The yield was 64 per cent. of the theoretical:0.1233 gave 0.3083 CO, and 0.1213 H,O.0.2178 required 11.3 C.C.O'lN-NaOH.a-Hydroxy-a-octyldodecamn&carb oxylic acid is sparingly solublein alcohol, acetone, or benzene in the cold, but dissolves readilyon heating; it is sparingly soluble in hot ether, and is insolublein light petroleum. It crystaIlises from acetone in needles, melt-ing a t 115-116O. The white silver salt was obtained on addinga warm solution of the sodium salt of the acid to a warm solutionof silver nitrate :C=68*19; H=11*01.M.W. = 386.34.M.W. = 385.6.CZ2H4,O5 requires C = 68.33 ; H = 10.96 per cent.0.2206 gave 0.0784 Ag. Ag=35-54.C,2H4,05Ag2 requires Ag = 35.96 per cent.When the acid is heated, it behaves exactly like a-hydroxy-a-octylsebacic acid, in that it readily loses the elements of water.The product is a viscid oil, which shows no signs of solidifyingwhen kept; for several weeks.It readily reduces an alkaline solu-tion of potassium permanganate, but does not decolorise a solutionof bromine in chloroform.Prepration of p-Xetohelzeicosoic A c i d ,CH,*[CH,],*CO.[CH,],,*CO,H.Eight grams of a-hydroxy-a-octyldodecanedicarboxylic acid weredissolved in a mixture of 120 C.C. of acetone and 20 C.C. of water,and finely powdered po€assium permanganate was added to thesolution. There was no action in the cold, but, on warming,oxidation immediately took place, and became very energetic a tthe boiling point of the acetone. The permanganate was addedin small quantities a t a time until no further oxidation ttook place.The acetone was evaporated, the manganese dioxide dissolved bymeans of dilute sulphuric acid and sulphur dioxide, and the pre-cipitatod acid collected and crystallised from acetone :M.W.= 339.4.0.1194 gave 0.3240 CO, and 0.1273 H,O.0.5260 required 15.5 C.C. 0.1iV-NaOH.p-KetolwTzeicosoic acid is readily soluble in cold chloroform,sparingly so in alcohol, benzene, or ether, and insoluble in lightpetroleum. It crystallises from acetone in glistening, micaceousplates, melting a t 89-90°. The white silver salt was obtainedby adding a warm solution of the sodium salt t o a warm solutionof silver nitrate:C=7.4.01; H=11*93.M.W. = 340.32. C21H4003 requires C= 74.05 ; H = 11.85 per cent.8 x 2516 LE SUEUR AND WITEERS: THE MECHANISM0,2224 gave 0.0538 Ag. Ag=24*19.C2,H3,O3Ag requires Ag = 24.16 per cent.Methyl p-ke toheneicosoa te, CH,* [ CH,],*CO*[ CH2]ll*C02Me, wasprepared by the method used for the preparation of methyl 8-keto-margarate (p.2806), and was purified by crystallisation frommethyl alcohol, from which it separates in glistening, thin plates,melting a t 59-60°. It is readily soluble in ether, chloroform, orbenzene in the cold, and dissolves sparingly in cold acetone oralcohol :0.1296 gave 0.3535 CO, and 0.1402 H,O.C,,H,,O, requires C = 74-50 ; H = 11.95 per cent.Et h y l p-keto heneicosoa t e, CH,=[CH,],* CO*LC?H,],,*C02Et~ wasprepared by the method used for the preparation of the methylester, and was crystallised from dilute alcohol, from which itseparates in glistening leaflets, melting a t 56O. It is sparinglysoluble' in cold alcohol, and dissolves readily in the other commonorganic solvents :C=74-39; H=12*10.0.1463 gave 0*4010 CO, and 0.1593 H,O.C~H4403 requires C = 74.90 ; H = 12.04 per cent.The' semicarbaame was prepared by the method employed forthe preparation of t'he semicarbazone of 8-ketomargaric acid, andwas purified by crystallisation from acetone, from which itaeparates in aggregates of slender needles, melting a t 104-105°.It is sparingly soluble in boiling acetone or ethyl acet'ate, and in-soluble in light petroleum or ether:C=74*75; H=12.18.0.1978 gave 18.6 C.C.N, a t 22O and 763 mm. N=10*74.C2,H,,0,N, requires N = 10.58 per cent.Syntkesis .of a-Hydroxy-a-octyldodecanedicarh oxylic A cid fromp-Xetoheneicosoic Acid.The' method used to effect this synthesis was practically identicalwith that employed for the preparation of a-hydroxy-a-octylsebacicacid from 8-ketomargaric acid.The addition of the hydrogencyanide in this case also was very slow, and the complete liydro-lysis of the hydroxy-cyanide difficult to effect. The crude acidwas crystallised from chloroform until its melting point was con-stant, at 115-116O. A mixture of equal parts of this acid andthe original a-hydroxy-a-octyldodecanedicarboxylic acid melted a texactly the same' temperature :0.1115 gave 0.2788 CO, and 011094 H,O.0.2590 required 13.0 C.C. 0-1N-NaOH.C,zH4z0, requirw C= 68.33; H= 10.96 per cent.I n order t o confirm further the identity of the synthetic acidC=68*20; H=10.98.M.W. = 398.M.W.= 386OF THE ACTION OF FUSED ALKALIS, PART I. 2817with the a-hydroxy-a-octyldodecanedicarboxylic acid obtained bythe fusion of dihydroxybehenic acid with potassium hydroxide, asmall quantity of it was oxidised with potassium permanganate inacetone solution, when an acid was obtained which melted a t89-90°, and had all the properties of the p-ketoheneicosoic acidproduced by the oxidation, under similar conditions, of a-hydroxy-a-octyldodecnnedicarboxylic acid.Constitution of the Ketorzic Acid, C21H4003.The oxime, of the acid, C,,H,,O,, was prepared by the methoddescribed on page 2807, and was converted into1 the correspondingamides by heating with five times its volume of concentratedsulphuric acid for two and a-half hours on the water-bath. Theproduct was poured on crushed ice, and the solid collected andcrystallised irom glacial acetic acid containing a little water, fromwhich it separates in aggregates of stout prisms, melting a t85*5-86*5° 10.2667 gave 9.3 C.C.N, a t ZOO and 764 mm.The above isomeric amides were hydrolysed by heating withhydrochloric acid in a sealed tube, as described on page 2808. Theproduct was diluted largely with water, and distilled in a currentof steam (didillate 1). The residue was then made strongly alka-line, and distilled in a current of steam (distillate 2).Distillate 1 was extracted with etlier, the ethereal solutionwashed, dried, evaporated, and the residue distilled, when it allpassed over a t 150--155O/31 mm.It was fractionally distilledunder the ordinary pressure, and the fraction boiling a t 248-249Owas collected for analysis. It readily solidified when cooled inice. (Found, M.W. = 157.9. C9HI8O2 requires M.W. = 158.1.)The zinc salt was prepared in the usual way, and, after crystallisa-tion from alcohol, melted a t 136O, proving the acid to be n-nonoicN=4*02.C,,H,,O,N requires N = 3-94 per cent.. - acid.Distillate 2.-The amine was isolated from this distillate asdescribed on page 2809, and was obtained as a clear, colourlessliquid, boiling a t 174--176O, which was identified as octylamineby analysis of the platinichloride (Found, Pt.= 29.07. Calc.,Pt=29*21 per cent.), and by the preparatdon of phenyloctyl-carbamide which melted at 79-80°.The mother liquor left after obtaining distillate 2 was con-centrated to about 350 c.c., and then poured into a slight excessof concentrated hydrochloric acid.The solid which separated oncooling was collected, dried, and boiled with 50 C.C. of alcohol.The solutioa was filtered, and the filtrate concentrated t o abou2818 THE MECHANISM OF THE ACTION OF FUSED ALKALIS.20 c.c., and then mixed with 50 C.C. of ether, when a voluminous,crystalline mass separated. This was collected (filtrate 3) andcrystallised from hot water, from which it separates in thinlamellae, melting a t 163O:0.1782 gave 8.8 C.C. N, a t 20° and 778 mm.A portion was converted into the pZati?aichloride, which melts0.2394 gave 0.0550 Pt. Pt=22*97.The' substance is theref ore the hydrochloride of A-aminohuricacid, CO2H-[CH2],,*NH2,HC1.It is insoluble in hot or cold ether,benzene, chloroform, or acetone, freely soluble in alcohol, andmoderately so in water.The free amino-acid was isolated by adding the calculatedvolume of a dilute sodium hydroxide solution to a warm, aqueoussolution of the above pure hydrochloride'. The white, crystallinemass which separated was collected, washed with cold water, anddissolved in boiling water, from which it crystallised on cooling inlong, thin plates with almost square ends:0.0942 gave 0.2306 CO, and 0.0982 H20.0.1574 ,, 9.0 C.C. N2 a6 18O and 770 mm. N=6.70.N=5.75.Cl2H2,O2N,HC1 requires N =5*57 per cent.and decomposes a t 209O:(C,2H2,0,N)2H2PtC1, requires Pt = 23.21 per cent.C=66*76; H=11.67.C,,H,O,N requires C = 66.91 ; H = 11.71 ; N = 6-51 per cent.A-Aminohuric acid, NH2*[CHJ,,*CO2H, melts a t 184O, and ispractically insoluble in the common organic solvents.I n order more completely to chazacterise the acid, its P-naph-thalenesulphonyl derivative was prepared.F o r this purpose, amixtare of the amino-acid (1 mol.), N-sodium hydroxide (1 mol.),and an ethereal solution of P-napht8halenesulphonyl chloride(2 mols.) was shaken in a stoppered bottle. At intervals of onehour, three more molecular proportions of sodium hydroxide wereadded, and the shaking was prolonged altogether f o r five hours.The mass was diluted with water and allowed t o flow into cold,dilute sulphuric acid, the ethereal layer being retained in aseparating funnel. The white solid which separated was collected,washed free from sulphuric acid, and dissolved in hot 25 per cent.alcohol, from which it crystallised in small flakes, melting at 115O:C22H3104NS requires N = 3-46 per cent.C10H7*S02-NH[CH2]ll*C02H,is readily soluble in hot alcohol, sparingly so in cold alcohol, hotether, acetone, or water, and insoluble in light petroleum.0.1238 gave 3.8 C.C. N2 a t 18O and 750 mm.A-P- Na ph t ha I en esulp h o n yla min olauric acid,N=3.50THE POLYSULPHIDES OF THE ALKALI METALS. PART 11. 2819The alcohol-ether filtrate 3 (p. 2818) was evaporated on thewater-bath, and ths residue diluted with water. On leaving thissolution, crystals soon separated ; these were collected, and crystal-lised first from water and then from benzene, from which the sub-stance was deposited as a crystalline powder, melting a t 113-5O.(Found, C = 63.89 ; H = 9.92. M.W. = 247.2. C,,H,,O, requiresC=63*88; H=9*91 per cent. M.W.=244*19.) A portion wasconverted into the silver salt (Found : Ag= 46.89. CI3H,0,Ag,requires Ag=47*11 per cent.) and another portion into the amide,which melted a t 174-175O. (Found : N= 11.66. C,,H,60,N,requires N = 11.57 per cent,.)The dicarboxylic acid which resulted from the hydrolysis of theabove mixture of isomeric amides was thus fully identified withbrassylic acid, CO2H[CH2],,*CO,€I. Fileti and Ponzio (J. pr.Chem., 1893, [ii], 48, 323) found as the, melting point of brassylicacid 114O, and of the amide 177O.The yields of the four substances obtained by the hydrolysis ofthe above mixed amides were as follows:n-Nonoic acid ................................. 90 per cent. of the theoretical.Octylamine .................................... 89 ,, 99 99Brassylic acid 57 ,, 27 ,Y Hydrochloride of A-aminolauric acid.. .... 55 ,, Y, I >.................................CHEMICAL LABORATORY,ST. TfIOMAS’S HOSPITAL,LONDON, S.E

ISSN:0368-1645    

DOI:10.1039/CT9140502800

出版商:RSC    

年代:1914

数据来源: RSC

摘要:

THE POLYSULPHIDES OF THE ALKALI METALS. PART 11. 2819CCLXIV.-The Polysulphides of the Alkali Metals,Part II. The Polysulphides of Potassium.By ALEXANDER RULE and JOHN SMEATH THOMAS.IN a previous paper (Rule and Thomas, this vol., p. 177) weredescribed the results of an investigation of the action of sulphur onalcoholic solutions of pure sodium hydrosulphide. It was shownthat the reaction provided a simple and certain means of preparingsodium tetrasulphide in the pure anhydrous state, and further, thatthe polysulphide product obtained as a result of the reaction undervaried conditions consisted almost entirely of the tetrasulphide.It has been pointed out by several authors that much of theearlier work on the polysulphides of sodium and potassium is quiteuntrustworthy, but descriptions of series of these compounds basedon the results of such work still appear in many texbbooks.I n thecam of potassium the highest polysulphide obtainable is generall2820 RULE AND THOMAS:accepted to be the pentasulphide, which seems to be fairly wellcharacterised.Bloxam (Thesis, London, 1898; T., 1900, 77, 753), in criticisingthe work of previous authors, has shown that by the methodsusually adopted it is impossible to obtain pure polysulphides in thesolid state. When aqueous solutions of the monosulphides areemployed the resulting product always contains thiosulphate, andBloxam attributed tahe formation of that compound to the presenceof hydroxides Fn the solution as a result of the hydrolysis of themonosulphidea.Bloxam investigated the action of sulphur on aqueous solutionsof potassium hydrosulphide, which is only very slightly hydrolysed(compars Walker, Zeitsch.phpilcal. Chem., 1900, 32, 137). Al-though he does not appear to have succeeded in isolating any com-pound of undoubted chemical individuality, yetl he established thefact that within certain limits the sulphur added to the solutionreacted with a portion only of the hydrosulphide, and t*he resultingpolysulphide product was richer in sulphur than a polysulphidecorresponding t o the1 amount of sulphur added. It is probable khatin aqueous solution there is a tendency f o r the formation of onepredominating polysulphide, and this would account for Bloxam’sresults, as that author has pointed out.I n the case of alcoholicsolutions the work described in the present paper proves that theaction of sulphur tends undoubtedly t o the formation of one poly-sulphide only, namely, the pentasulphide, which has been isolatedin the pure anhydrous condition.The preparation of anhydrous potassium pentasulphide by theaction of sulphur on potassium in liquid ammonia has also beendescribed by Hugot (Compt. rend., 1899, 129, 388), but no accountis given of the properties of ths product.Action of Srulphur on Alcoholic Solutions of PotassiumHydrosulphide.I n a previous paper (T., 1911, 99, 558) one of us described thepreparation of pure potassium hydrosulphide by the action ofhydrogen sulphide on an alcoholic solution of potassium ethoxide.I n the work now under consideration solutions prepared in thatway were used throughout, and the actual experimental detailswere’ precisely similar t o those already described in the paper ontho polysulphides of sodium (Zoc.cit.), t o which reference may bemade.A series of experiments was carried out in which quantities ofsulphur corresponding with possible polysulphides of potassiumfrom the di- up to the hexa-sulphide were added to alcoholic soluTHE POLYSULPHIDES OF THE ALKALI METALS. PART 11. 2821tions of the hydrosulphide of the same concentration throughout.Since the only polysulphide product obtained as a result of theseexperiments was t,he pentasulphide the preparation and propertiesof that compound will be dealt with in the first place.Potassium Pentasulphide.One gram of potassium was dissolved in 15 C.C.of absolute ethylaIcohol,* and the solution was saturated with dry hydrogensulphide. 1.64 Grams of finely ground recrystallised rhombicsulphur were added, and the solution was boiled gently on a water-batn for about one hour, a rapid current of dry hydrogen beingpassed through it. On the addition of the sulphur a vigorousreaction a t once took place even in the cold with evolution ofhydrogen sulphide, and the solution became deep red. The sulphurdissolved, and after a short time1 a bright orange-red, crystallinesolid separated out. Tho solution was concentrated to about 5 c.c.,the product collected on a filter, sprayed with alcohol, and keptin a vacuum over phosphoric oxide.The dry product consisted of a mass of glistening crystals, andappeared to be perfectly homogelgeous.The yield was 2.5 grams,that is, 82 per cent. of t h e theoretical amount:0.3506 gave 0.2560 K,SO,. K = 32.73.0.3475 ,, 0'1850 S. f(S)=53*23.0.3027 ,, 1.4742 BaSO,. S=66.90.Potassium penfasul7hide is extremely hygroscopic, and is rapidlyosidised on exposure to the air, with liberation of sulphur. Itdissolves readily in water to form a clear, deep orange solution,which becomes dark red on heating. It is only sparingly solublein alcohol, forming a red solution, which also becomes darker onheating. Both the aqueous and alcoholic solutions soon begin t odeposit sulphur when allowed to remain in the air. Biltz andDorfurt (Ber., 1905, 43, 53) state that rubidium pentasulphide isa t once1 decomposed on treatment with water, whilst msium pent'a-sulphide is apparently n o t affected.It is noteworthy that potassiumpentasulphide should be more stable in this respect than the corre-sponding rubidium compound.On heating in a capillary tube the substance begins t o darkena t about 130°, and a t 182O becomes quite black, this change beingsharply marked; it begins to sinter a t 200-205°, and melts notvery sharply a t about 220O. On cooling the substance passes through* Commercial absolute alcohol was shaken for two days over freshly preparedt (S) indicates " poljsulphide sulphur. "K2SLrequirm K = 32.77 ; (S) = 53.78 ; S = 67.22 per cent.quicklime, boiled over quicklime and then distilled2822 RULE AND THOMAS:the same series of colour changes in the reverse order, and finallyassumes its original appearance.No deposit of sulphur was noticedon the walls on the tube, and the solidified product dissolved to aperfectly clear solution in cold water. Potassium pentasulphidecan therefore be fused without decomposition.The majority of organic solvents are without action on the penta-sulphide, but a very striking behaviour may be noted in the caseof pyridine. On treating tlhe substance with pure pyridine thelatter is colsured an intense brownish-red, and on heating themixture the liquid becomes quite opaque. A definite reactionappears to take place, and the observed effect may be due to theformation of an additive compound, but apparently very little ofthe pent'asulphide dissolves in the pyridine.With sodium tetra-sulphide the action of pyridine is even more marked, the solventbeing a t once coloured intensely green and the solid slowly chang-ing in colour to bright yellow. This action is being further investi-gated.Nitrobenzene, on treatment with the pentasulphide, is colouredmagenta in the cold. On heating the colour fades, and the solidcan be fused below the liquid; on cooling again the colour returns,and the pentasulphide remains apparently unchanged. Thisbehaviour with nibrobenzene is 'similar to that of rubidium penta-sulphide, as noted by Biltz and Dorfurt (Zoc. cit.).When shaken with alcohol a t the ordinary temperature the penta-sulphide forms a well-defined, bright yellow alcoholate, whichcrystzllises in small, monoclinic prisms.From a consideration of the resulta obtained by numerousworkers in this field it appears to have been generally assumed thata series of polysulphides from the di- up to the penta-sulphide couldbe prepared by adding the theoretical amount of sulphur t o aqueoussolutions of the mono- or hydro-sulphide.The results obtained bythe use of alcoholic solutions of sodium hydrosulphide and varyingquantities of sulphur have already been dealt with in detail(Zoc. cit.), and it is therefore only necessary t o mention briefly thenature of the products of ths action of sulphur on alcoholic 6011.1-tions of potassium hydrosulphide. With the proportions for thedisulphide a small quantity of pentasulphide separated from thehot solution, and on cooling a yellow product was obtained, whichwas obviously not homogeneous, and consisted of a mixture ofpentasulphide and unchanged hydrosulphide.A similar result wasobtained when proportions for the trisulphide were used, but theyield of pentasulphide was greater.With the proportions for the tetrasulphide a comparatively gooTHE POLYSULPHIDES OF THE ALKALI METALS. PART 11. 2823yield of pure pentasulphide was obtained, separating out from thehot solution. With the proportJons f o r a possible hexasulphide itwas found that all the sulphur added dissolved in the first place,and the solid product consisted of the pentasulphide mixed with alittle sulphur, which remained undissolved on treating the productwith water.The solution from which this product separated gavea copious precipitate of sulphur on treatment with water, whereasin all other cases mentioned the solution remained perfectly clear.The results are therefore very similar t o those obtained in thecase of sodium, except that here there is not the slightest indicationof the formation of higher polysulphides when larger quantities ofsulphur than that corresponding with the pentasulphide are used.The moderate solubility of potassium pe'ntasulphide in alcohol hasalready been mentioned, and it might therefore be assumed thatthis compound is the saturation product, and that in the solutionitself a series of polysulphides might exist in equilibrium accordingto the conditions of experiment.I n order to test the accuracy ofthis assumption and to gain some idea as t o the nature of thesubstances in solution after the action of sulphur on the hydro-sulphide, a series of measurements similar to those described inconnexion with the polysulphides of sodium was carried out.It will be seen that according to the equation:2KHS + ZS = &Sz+l + H2S,the amount of hydrogen sulphide formed is strictly proportionalto the amount of hydrosulphide involved in the reaction. By deter-mining the amounts of hydrogen sulphide evolved in the courseof a series of reactions with different amounts of sulphur it ispossible t.0 decide whether (1) a series of polysulphides is formedaccording to the amount of sulphur added, (2) only one poly-sulphide is formed independent of the amount of sulphur present,or whether (3) an equilibrium mixture of several polysulphides isformed.The apparatus used and the method adopted were exactly similarto those employed in the case of sodium (Zoc.c i t . ) , except thatammoniacal hydrogen peroxide was used throughout as theabsorbent for hydrogen sulphide instead of bromine. Owing to thesparing solubility of potassium pentasulphide in alcohol, and thenecessity of preventing any solid product from separating outduring the experiment, it was necessary to work with fairly dilutesolutions of the hydrosulphide, and an error is thereby introducedowing to the fact that the hydrosulphide undergoes slight alco-holysis with the formation of hydrogen sulphide.Since it wasnecessary to carry out the determination in a stream of hydrogenthe equilibrium was constantly disturbed, and in consequence 2824 RULE AND THOMAS:certain amount of hydrogen sulphide derived from this alcoholysiswas driven over into the absorbent. I n consequence the resultsobtained are too high. For the purpose of ascertaining the magni-tude of this error, blank experiments, in which tlie conditionsapproximated as nearly as possible to those employed in the actualdeterminations, were performed first of all with solutions of potass-ium hydrosulphide of varying concentration. Using a normalsolution it was found that after boiling in a current of hydrogenfor forty-five minutes the amount of hydrogen sulphide evolved andcalculated for 72 grams of potassium hydrosulphide was 0.54 gram;a O.5N-solution under similar conditions gave 1.2 grams,It will be seen that the amount of unchanged hydrosulphideremaining in solution decreases progressively with addition ofsulphur, and therefore the error decreases as the amount of sulphurincreases.I n order to overcome this error as far as possible theconcentration of the hydrosulphide solutions used was varied fromN to 0*25N, the effect of this being to keep the solutions nearlysaturated with respect to the pentasulphide formed, assuming thatto be the chief product of the reaction, throughout the series ofdeterminations.The results are expressed graphically in the diagram ; tlie numbersin brackets a t the various points on the curve indicate the concen-trations of the hydrosulphide solutions in terms of normality.The results show that there is a gradual increase in the amountof hydrogen sulphide evolved with increase in the amount ofsulphur added.I n the diagram the theoretical straight lines areshown which would indicate the values for the tetrasulphide andpentasulphide if these were the only polysulphides respectivelyformed in the course of tho reaction.The curve a t first approximates very closely to the values for thetetrasulphideaA but then bends away and eventually crosses thepentasulphide line not far away from the maximum, after whichthe values become practically constant. Taking into considerationthe effect of aIcoholysis it may be stated that all the values on theleft-hand branch of the curve lie below the tetrasulphide line.Although the lower values possibly indicate the presence of poly-sulphides lower than the pentasulphide in the solution, and moreespecially of the tetrasulphide, it must be noted that unchangedhydrosulphide still remains in solution below the pentasulphidestage, and it is not until the amount of sulphur corresponding withthe pentasulphide is present that the amount of hydrogen sulphideevolved is approximately equal to the maximum obtained in theseries of determinations.It is clear that when quantities of sulphur less than those correTEE POLYSULPHIDES OF THE ALKALI METALS.PART 11. 2825sponding with the tetrasulphide are used, very little di- or tri-sulphide, if any, can be formed, otherwise the values for hydrogensulphide a t these stages would be much higher.On the other hand,since the value a t the pentasulphide stage is very near the theo-retical maximum for hydrogen sulphide there is no indication ofthe presence of any higher polysulphides in solution (compare thecurve for sodium hydrosulphide, loc. cit.). As a result of thisinvestigation, therefore, as well as from the results of experimentsin which the solid was allowed to separate out, it is fair t o con-clude that, the chief product of the action of sulphur on potassiumhydrosulphide under the conditions described is the pentasulphide,and a t the same time it is obvious that it is impossible' t o obtainK2% K2S3 K2S4 K2S5 K,S,Qranzs of sulphur nddedpcr 72 grains of KHS.the lower polysulphides simply by adding the equivalent quantityof sulphur to sohtions of the hydrosulphide.Solubility of Sulphur in, Alcoholic Solutions of PotassiumHydrosul phide.It has already been shown by Kuster and Heberlein (Zeitsch.anorg.Chem., 1905, 43, 53) that aqueous solutions of sodium mono-sulphide are able to dissolve considerably more sulphur than isrepresented by any polysulphide hitherto isolated. The presentauthors have also shown (Zoc. cit.) that alcoholic solutions of sodiumhydrosulphide under certain conditions dissolve sulphur t o anextent represented by the formula Na,S6.,. A similar determina-tion was made in the case of potassium hydrosulphide.It has beenpointed out above that the solution is capable of dissolving at leas2826 RULE AND THOMAS:a proportion of sulphur corresponding with a possible hexasulphide,although such a product does not separate out.A 0'25N-solution of the hydrosulphide was shaken with excess ofsulphur in a flask in a thermostat a t 25O f o r forty-eight hours, acontinuous current of dry hydrogen being passed through the solu-tion. The solution was then allowed t o settle, and a portion wasremoved by means of a pipette, introduced into bromine water,made up to 1 litre, and the potassium and sulphur determined inaliquot portions :250 C.C. gave 0.1247 K,SO,.250 ,, ,, 1.0774 BaSO,. S=0.148.Atomic ratio, K = 1 : S = 3.23, corresponding with K, : S6.46.I n the case of sodium hydrosulphide, using a 2N-solution a t 25*,the ratio found was 2 : 6.36, and a t 8 1 O it was 2 : 6.9, but thefigure for the higher temperature is rather difficult to determinewith accuracy.The addition of water t o these solutions resulted in a copiousprecipitation of sulphur, and the same holds good f o r all solutionscontaining sulphur in proportions higher than that correspondingwith the pentasulphide. It must be noted that in these experimentsthe solubility of sulphur in alcohol is not taken into account, butin any case it is so small as t o hays very little effect on the results.K=0'0559.Actiow of MetaZlic Potassium on Alcoholic Solutions of thePentasulphide.When alcoholic solutions of sodium tetrasulphide are treated withmetallic sodium, reduction of the polysulphide takes place, andpractically pure sodium disulphide separatas out.A series ofexperiments was performed in order t o determine if metallic potass-ium had a similar action on the pentasulphide. Reduction certainlytakes place, but in no case were the products obtained individualcompounds, but rather mixtures of lower polysulphides with un-changed pentasulphide. When excess of potassium was used thesolution became paler in colour, and a yellow product separatedout, which on analysis approximated t o the t'risulphide, but thefigure for polysulphide sulphur was too high.I n other experiments with more dilute solutions and varyingamounts of potassium 1 he products always contained unchangedpentasulphide, which appears to be " salted out " from the solutionby the potassium ethoxide formed.In all cases the figure for poly-sulphide sulphur was higher than that reqnired for the trisulphide.The method therefore does not provide a means of arriving a t adefinite lower polysulphide as in the case of sodium, and considerTHE POLYSULPHIDES OF THE ALKALI METALS. PART 11. 2827ing the sensitive nahure of the products separation of the con-stitue.nt compounds would be a difficult operation.General Conclusions.Although it cannot be claimed that the results of this investiga-tion throw any further light on the actual constitution of the poly-sulphides, yet it may afford some evidence as to the extent towhich sulphur can be taken up by any one member of the series ofalkali metals to form a stable polysulphide. Biltz and Dorfiirt(loc.cit.; Zeitsch. anorg. Chem., 1906, 48, 297; 50, 67) weresuccessful in obtaining both the tetra- and penta-sulphidm ofrubidium and caesium by the action of sulphur on aqueous solutionsof the monosulphides. These compounds are perfectly well defined,and, moreover, the authors mentioned were able to show the exist-ence of hexasulphides which were characterised thermo-analyticallyin the course of a freezing-point-curve determination. It is hopedlater to give the results of a similar determination for potassium-sulphur and sodium-sulphur, but in the meantime it may be notedthat no evidence has been olbtained in the’ course of the authors’experiments of the existence of potassium hexasulphide.Taking into consideration the results of the work on potassium,rubidium, and wsium, we are able to recognise three definite andstable pentasulphides exhibiting a gradation in respect of certainproperties, f o r example, solubility.The solubility in alcoholdecreases with increase in atomic weight of the alkali metal, andit is fair to assume thatl the solubility in water would vary in thesame direction, thus bringing these compounds into line with otherseries of salts of &he same metals, such as the alums, platini-chlorides, etc.I n the case of sodium we find that the highest stable polysulphideis the tetrasulphide, and although under cert,ain conditions thereis a tendency to form higher polysulphides, yet there is no definiteevidence of the existence of a pentasulphide in the solid state,although the S,” anion may be present in solution.Practically nothing is known concerning polysulphides of lithium,although a disulphide is mpposed to exist.It would be interesting to’ determine if, by working with alcoholicsolutions of rubidium and caesium hydrosulphides, the hexasulphidesof these metals would separate out as stable compounds in thesolid state, and the authors hope to carry out this investigationvery shortly.Tho fact that alcoholic solutions of sodium tetrasulphide andpotassium pentasulphides are still able up to a certain point todissolve further quantities of sulphur demonstratas the tendency o2828 THE POLYSULPHIDES OF THE ALKALI METALS. PART 11.the sulphur complex in each case to combine with more sulphur.A t the szme time, however, this addit(iona1 sulphur is apparentlyin a looser state of combination than that in the stable complexitsell, since it is precipitated on the addition of water to thesolution.It is possible that the tetrasulphide complex in the caseof sodium, and the pentasulphide complex in the! case of potassiumrepresent the limits within which ordinary valency considerationsapply, and that the sulphur which dissolves over and above thesestages may be loosely associated t o the complex as a result of theresidual affinity exerted by the latter.These facts taken in conjunction with the work on rubidium andcaesium point t o the distinct influence of the metal itself on thenumber of atoms in the stable sulphur complex, and this view isalso taken by Biltz and Dorfurt, who apply the well-known electro-affinity theory of Abegg and Bodlander (Zeitsch.amorg. Chem.,1899, 20, 457) to account for the formation of higher polysulphidesof the alkali metals of higher atomic weight.Abegg and Bodlander show that where the ionising tendency(Ionisierungstendenz) of the metal is considerable that tendency isimparted to the anion which may norinally show a weak ionisingtendency. The anion, in order to " strengthen " itself, then tendsto combine with other atoms or groups to form a complex. Theionising tendency of the alkali metals is shown to increase withincrease of atomic weight, and Biltz and Dorfurt apparently con-sider that, in the case of the polysulphides, as the atomic weightof the metal insreases there will be alz increase in the number ofsulphur atoms which go to make up the highest stable complex.On the other hand, Hamburger and Abegg (Zeitsch.anorg.Chem., 1906, 50, 437) in discussing the results of an investigationof the polyiodides of the alkali metals consider that in solution ionsof different 'degrees of complexity are present, and that th0 parti-cular polyiodide which separates out depends entirely on the parti-cular ionic combination the solubility product of which is firstexceeded. Moreover, it does not follow that the compound whichseparates out will represent a combination of the cation with theanion present in greatest concentration. The f a d that the higherpolyiodides are more readily formed as we pass up the series ofalkali metals from lithium to cEsium is explained on the groundthat the solubilities of the higher polyiodides decrease in the sameorder, like the platinichlorides, etc.Abegg and Bodlander have shown that this inverse order ofsolubility is frequently exhibited in the' case of strong anions incombination with increasingly strong cations, and a normally weakanion becomes stronger owing to addition resulting in the formatioBISSETT: THE REMOVAL OF SULPHUR FROM SILVER. 2829of complexes, a fact which is in agreement with the electro-affinitytheory.It will be seen that Hamburger and Abegg (Zoc. cit.), in dealingwith the polyiodides, and in referring also to the work of Biltzand Dorfurt, do not consider that the cation has a definite influ-ence on the particular number of atoms taken up by the aniont o form a complex, but only on the formation of complexes ingeneral, the degree of the substance separating out depending onsolubility conditions.So far as the polysulphides are concerned, the work of thepresent authors does undoubtedly sho'w the tmdency for the forma-tion of one particular polysulphidel ion in greatly predominatingamount, in the case of sodium the tetrasulphide ion, and in thatof potassium the pentasulphide ion. A t present, however, furtherconsiderations must be withheld until data are colIected sufficientt o test these conclusions.The authors are indebted to Mr. F. Fowweather, B.Sc., for assist-ance in carrying out a portion of the experimental work.INOEGANIG LABORATORIES,UNIVERSITY OF LIVERPOOL

ISSN:0368-1645    

DOI:10.1039/CT9140502819

出版商:RSC    

年代:1914

数据来源: RSC