摘要:

2242 GREEN AND SEN : AZOMETHINEAZO-DYES.CCXXXV. -Axomethineaxo-d yes.BY ARTHUR GEORUE GREEN and RAJENDRA NATH SEN.THE azomethine group mCH:N* lies between the azo-group *N:N* andthe stilbene group *CH:CH*, and in chromophoric power it alsooccupies an intermediate position. The objects of the present researchwere twofold, namely, first, to investigate the effect on the colour anddyeing properties of a compound containing both the azomethine andazo-groups, for example, whether such compounds would presentsimilarities to the azostilbene dyes ; and secondly, to ascertain how farthe presence of auxochromic groups is necessary for the manifestationof dyeing properties in such compounds. I n reference to the latterpoint it may be noted that it has been shown by Green arid Crosland(Trans., 1906, 89, 1602) that the dyes of the stilbene class are allazostil bene compounds containing no auxochromic group.Further-more, dyes which contain no auxochrome are known in some otherclasses (for example, diamine-gold-yellow).The method we have employed for preparing azomethineazo-dyesconsists in acting on amino-compounds with an azo-aldehyde. As aconvenient azo-aldehyde for the purpose, we have selected phenetoleazo-benzaldehydesulphonic acid, OEt*C,H,*N,*C,H,(S03H)*CH0, which isreadily prepared by oxidation of the dye chrysophenin G with coldaqueous permanganate. By making use of this aldehyde, a number ofazomethineazo-dyes have been prepared of varying degrees of com-plexity, and mostly containing no auxochromic group (unless theethoxy-group can be considered as such).These are all yellow,crystalline compounds, which dye wool in yellow shades. Althoughtolerably strong dyes, their colouring power appears somewhat inferiorto that of the azostilbene compounds. Affinity for cotton is onlyslightly developed, except in those cases in which a benzidine oranalogous residue is present, and even then it is considerably weakerthan in the stilbene series. The introduction of an auxochromic group(OH or NMe,) has practically no effect on the dyeing properties, anddoes not increase the tinctorial power, augment the affinity, or changethe shade. It is also remarkable that, whilst in the azo-series theintroduction of more than one azo-group usually deepens the colour,with these compounds the shade seems almost independent of thenumber of azomethine groups in the molecule ; thus the more complexcompounds having two azo-groups and two azomethine groups possessnearly the same colour and tinctorial intensity as those with a singleazo-group and a single azomethine group. On the other hand, whendissolved in concentrated sulphuric acid, differences of shade becomGREEN AND SEN : AZOMETHINEAZO-DYES.2243apparent : those derived froin aniline, aniline-p-sulphonic acid, andp-aminophenol dissolving with B yellowish red colour, those derivedfrorn benzidine and p-phenylenediamine with a crimson colour, andthose derived from a- or P-naphthylamine with a violet colour. Themembers of this series which do not contain an auxochromic grouppossess in common with t h e dyes of the azostilbene class a considerabledegree of fastness t o alkalis, chlorine, and light.On the other hand,like other azomethine compounds, they are more or less unstable towardsacids which tend to decompose them into the original aldehyde andamine.EXPERIMENTAL.Plieneto ZeaxobenxaZdehydesuZplzonnic Acid,This aldehyde was prepared by Green and Meyenberg’s method(Eng. Pat.. 1431 of 1898). One hundred grams of chrysophenin Gconc. (Farbenfabriken vorm. F. Gayer & Co.), which is equivalent toabout 92 grams of the pure dye,OE t C,H,* N2*C,H3( SO,Na)*CH: CH*C,H,( SO,Na)*N,* C,H,*OEt,were dissolved in 6 litres of bailing water. Into this solution, cooledto 0--5O by addition of ice, wits slowly run with rapid mechanicalstirring R 3 per cent.solution of potassium permanganate until thecolour of the latter was persistent (pale pink filtrate after saturatingwith sodium chloride). The quantity of permanganate required was29 grams. After allowing t o settle, the supernatant liquor wassiphoned off, and the precipitate collected. The solution containedonly a small quantity of aldehyde, which was isolated by salting outwith potassium or sodium chloride. The main quantity of the aldehydewas contained in the precipitate in admixture with the manganesedioxide. I n order to extract it, the precipitate was boiled two or threetimes with a litre of water, filtered from manganese dioxide, andpotassium chloride added to the hot filtrate until precipitation wascomplete.The potassium salt of the aldehydesulphonic acid thusobtained was collected, washed with 50 per cent. alcohol, and dried.The yield was 81. grams, or 80 per cent. of the theoretical.*The substance crystallises from water in orange-coloured, microscopicneedles, sparingly soluble in cold, but readily so in hot, water. Itreacts readily with phenylhydrazine, producing a reddish-orange phertyLhydrazone. With sodium hydrogen sulphite solution, it gives a yellow,* The large yield obtained affords incidentally an additional proof of RichardMeyer’s formula for chrysophenin (Bey., 1903, 36, 2970), and definitely establishesthe absence of an auxochromic (OH) group in this dye2244 GREEN AND SEN : AZOMETHINEAZO-DYES.crystalline bisulphite compound, I n concentrated sulphuric acid itdissolves with a red colour, which on dilution with water becomesyellow.The following results were obtained on analysis :Found, K=(I) 1G.12, (11) 10.18. S=(I) 9.0, (11) 8.9.C15H1,0,N,SK requires K = 10.48 ; S = 8.6 per cent.An estimation of nitrogen carried out with the barium salt gave :Found, N = 6.98.(C,,H1,O,N2S),Ba requires N = 6.97 per cent.A determination of the aldehyde group was effected by titrationwith a standard solution of phenylhydrazine hydrochloride (containing1 per cent. of the base) i n the presence of sodium acetate, employingp-nitrobenzaldehydesulphonic acid as indicator (I). Another method(11) consisted in titrating with a 0.5 per cent. solution of benzidinehydrochloride, but the end point was not very sharp :Found, CHO=(I) 7.66; (11) 65'3.For the preparation of the azornethine dyes, the same generalmethod was employed in all cases.This consisted in mixing inmolecular proportions IZ hot aqueous solution of the potassium salt ofthe aldehyde with a hot alcoholic or aqueous solution of the respectiveamine. A few drops of hydrochloric acid were afterwards added, andthe mixture was boiled for a few minutes to complete the condensa-tion, The solution was then neutralised with potassium carbonateand left to cool, and the product which separated was recrystallisedfrom dilute alcohol. In some cases (aniline, p-nitroaniline, amino-salicylic acid, and p-phenylenedimethyldiamine) the amine was dissolvedin dilute acetic acid, in which case the condensation completes itselfwithout the addition of hydrochloric acid.C,,H,,O,N,SK requires CHO = 7.8 per cent.Condensation Product with Aniline : PhenetoZeaxosuZphobenzyZidene-aniiine, OEt C,H,*N: N*C6H3(S0, H)*CH :N*C,H,.Itdissolves in hot water to an orange-yellow solution, but is almostinsoluble in cold water.It dyes wool a fast yellow from a neutral oracetic acid bath, but has no affinity for cotton :Found, N = 10.39.The free acid forms an orange-yellow, crystalline precipitate.C,,H1,O,N,S requires N = 10.27 per cent.Condensation Product with Aniline-p-subhonic Acid : PhennetoZecczo-suZphobenxyZ~deneccn~Zine-p-suZphonic Acid,OEt*C,H,*N: N*C,H,(SO,H)*CH: N*C,H,*SO,H,The potassium salt forms fine, reddiah-orange needles, fairly solublGREEN AND SEN : AZOMETHINEAZO-DYES, 2245in cold, and readily so in hot, water.wool, but has no affinity for cotton :It dyes fast yellow shades onFound, N = 7.58 ; K = 13.44.C,,H170vN,S2K2 requires N = 7.43 ; K = 13.85 per cent.Condensation Product with p-Nitroaniline ; P~Lenetoleaxoszl~hobenz~ I-idene-p-nitroaniline, OEt*C,H,*N:N*C,H,(SO,H)*~H:N*C,H,*~O,.The potassium salt cry stallises in bright reddish-orange needles,readily soluble in hot, and fairly so in cold, water.It dyes wool inreddish-yellow shades from a neutral or acetic acid bath, but has noaffinity for cotton ;Found, N = 11.12 ; I( = '7.75.C21H1v06N,SK requires N = 11-38 ; K = 7-93 per cent.Condensation Product with p-Aminophenol ; Fhenetoleaxosulphoben~yl-iderte-p-aminophenol, OE t C,H,*N N C,H,( S0,H) CH: N*C,H,*OH.The potassium salt forms fine orange needles, readily soluble in hotIt dyes wool in reddish-yellow shades, but has no affinity for water.cotton :Found, N = 9-04 ; K = 8.6 1.C21H,,0,N,SK requires N = 9-07 ; K = 8.42 per cent.Condensation Product with p-Arninosalicylic Acid ; Phenetoleaaosulpho-benxylideneaminosalicy Zic Acid,O E t ~ C , H 4 * N : N ~ ~ , ~ , ( ~ 0 3 H ) * ~ H : N * ~ , ~ ~ ~ The potassium salt crystallises in orange needles, readily soluble inIt dyes wool in reddish-yellow hot, but sparingly so in cold, water.shades fast to alkalis, but only has a small affinity for cotton :C,2H,707N,SK2 requires N = 7.70 ; K = 14.31 per cent.Found, N = 7.72 ; K = 13.98.Condensation Product with p-Phenylenedimethyldiamine. ; Phenetoleazo-suIpho6ennx~Zidene-p-phenylernediPnethyZd~amie,OEt *C6H4*N N C,H:,(SO,H)*CH: N C,E4*N (CH,),.The potcdum salt crystallises in water containing potassiumIt is fairly soluble inIt is easily decomposed by acids.carbonate in small leaflets of greenish lustre,cold, and readily so in hot, water.It dyes wool a dull yellow, but has very little affinity for cotton :Found, N=11*16; E ~ ( 8 - 2 6 .C2,H,,0,N4SK requires N = 1 1.43 ; K = 7-96 per cent2246 GREEN AND SEN : AZOMETHINEAZO-DYES.Condensation Product with a- Naphthylamine : PhenotollsaxoszclphobenzyZ-idene-a-n~~~thy Inmilze, OEt-C,H,*N: N*C,H,( S0,H ) C H: N C,,H7.The potassium salt forms bright orange, silky needles, sparinglysoluble in cold, more readily so in hot, water.It dyes wool reddish-yellow shades from a neutral or acetic acid bath, but has no affinity forcotton :Found, N = 8.51 ; K = 8.01,C,,H,,O,N,SK requires N = 8-45 ; K = 7.85 per cent.Condernsa t ion Product with p- Naph t h y lamine : Phene t okazoszc Zpho-bertz ylidene- P- napht h ytamim.The potassium salt forms fine orange needles, readily soluble in hot,It dyes wool reddish-yellow shades, but sparingly so in cold, water.but has no affinity for cotton :Found, N = 8.50 ; K = 7-96.C,,H,,O,N,SK requires N = 8.46 ; K = 7.85 per cent.Condensation Product with Aminoazobennxene : Phenetoleaxosdpho-benz ylidensaminoa~obe~zene,OEt C,H,*N : N* C,H, (S0,H) CH : N * C,H,* N: N* C,H,.The potassium salt crystallises from dilute alcohol in beautiful 9orange, silky needles.It dissolves in hot water to a yellow solution,but is sparingly soluble in the cold solvent. The addition of hydro-chloric acid produces a red precipitate of the free acid. It dyes woolfrom a neutral or acetic acid bath in yellow shades, which are very fast,t o alkalis and light. It also has a moderate affinity for cotton, whichit dyes from a salt-bath, The affinity for cotton is, however,considerably less than that of chrysophenin, to which it presents somestructural analogy :Found, N = 12.80 ; K = 6.93.C27H220,N,SK requires N = 12.70 j K = 7-07 per cent.Condensation Product with p- Phenylenediamine : Bisphernstoleanxo-su~hobenzyllidene-p-piLen ylenediamins,N:CH*C,H3(S0,H)*N,*C,H,*OEtH4<N:CH.C,=3(S0,H)*N,. C,H,*OEt'The potassium salt was obtained as a brownish-yellow powder,It dyes wool in reddish-yellow shades fast sparingly soluble in waterOREEN AND SEN : AZOMETHINEAZO-DYES 2247to alkalis and light.greater affinity than the preceding conipound :I t also dyes cotton, for which it has a ratherFound, N = 9.98 ; K = 9.52.C3,H3,,OSN6S2K2 requires N = 10.29 ; K = 9.59 per cent.Condensniion Product with Benzidine : Bisphenetoleaxosulphobenzylidene-benxidine,~,H,*N:CH*C,H,(S0,H)*~20C6H4*OEtC,H,* N C H C,H,(SO,H) N,*C,H,* OEt 'The potassium salt forms orange needles, moderately soluble in hot,but sparingly so in cold, water.Hydrochloric acid produces a redprecipitate. It dyes wool in fast reddish-yellow shades, and alsocotton from a salt-bath in yellow shades tolerably fast to soaping :Found, N = 9.30 ; K = 8.99.C,2H,,0,N,S2Z(2 requires N = 9.42 ; E( = 8-75 per cent.Condensation Product with Hydraxins ; Biq~henetoZeaxoberzaZdaz~w-disulplhonic Acid,OE t C6H,*N2* C,H,( S0,H) CH: N*N: CH* C,H,( SO,H)*N,* C,H,-OEt.This compound was prepared in order to study the tinctorial effectof the double azomethine or aldazine group *CH:N*N:CH*. It isobtained by adding 1 gram of hydrazine sulphate dissolved in 20 C.C.of hot water to a solution of 5-7 grams of the aldehyde potassium saltin 300 C.C. of boiling water. The solution, when neutralised withpotassium carbonate, deposits the potassium salt as a crystalline, yellowprecipitate. It crystallises in fine orange needles, sparingly soluble inhot, but almost insoluble in cold, water. Hydrochloric acid produces ared precipitate of the free acid, It dyes wool from a neutral or aceticacid bath in reddish-yellow shades which are fast to alkalis and light.I t s affinity for cotton is rather small :Found, N = 11.22 ; I(= 10.42.C,,H,,0,N,S2E(2 requires N = 11.35 ; K = 10.58 per cent.DEPARTMENT OF TINOTORIAL CHEMISTRY.UNIVERSITY OF LEEDS

ISSN:0368-1645    

DOI:10.1039/CT9109702242

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

2248 GAZDAR AND SMILES : AROMATIC HYDROXY-SULPHOXIDES.ccxxxv1.- -Aromatic Hycl~oxy-sulp hoxides.By MAUD GAZDAR and SAMUEL SMILES.IN the study of the sulphination of certain phenolic ethers (Smilesand Le Rossignol, Trans., 1908, 93, 745) several thionyl derivativesof these substances were obtained, and it was found that thesemethoxy- and ethoxy-sulphoxides when dissolved in concen tratedsulphuric acid may be converted by excess of phenolic ether into thetriarylsulphonium salts. Later investigation of the correspondinghydroxy-derivatives showed that the reaction is not generally applic-able to these substances, for, whilst di-p-hydroxyphenyl sulphoxide(Smiles and Bain, Trans., 1907, 9 1, 11 18) yields the trihydroxyphenyl-sulphonium base, the di-p-hydroxym-tolyl sulphoxide does not (Smilesand Hilditch, Proc., 1907, 23,161). The exceptional behaviour of thispcresol sulphoxide is of peculiar interest, for the corresponding dimethylether, ( C,H3Me-OMe),S0, readily furiishes the triarylsulphoniurnderivative.Although the so-called ‘‘ steric ” conditions which are setup by substitution in the aromatic nucleiis are known to be capable ofretarding this reaction (Smiles and Le Rossignol, Zoc. cit.), it cannot besupposed that their influence is the cause of the inactivity of thisp-cresol sulphoxide. For it is evident from previous experience of‘‘ steric hindrance ” that, if there be any difference in reactivitybetween a phenol and its ether, it is the latter that should be lessreactive, whereas in the present case the reverse relation holds.It is a remarkable fact that of the eleven hydroxy- or methoxy-phenyl sulphbxides which have been hitherto examined, all givebrilliantly coloured solutions in concentrated sulphuric acid, andi t therefore seemed probable that in effecting the condensation of thesulphoxide with the phenolic ether by means of this reagent, someintermediate compound is formed, and that it is the reactivity of thissubstance that determines the formation of the sulphonium salt.As a preliminary step in the investigation, we have found itnecessary to extend the range of material available, since very littleis known of the aromatic hydroxy-sulphoxides, only one, apparently,having been obtained in a pure condition.The present paper deals with the aulphoxides of p-cresol, p-chloro-phenol, and o-chlorophenol, The investigation is not yet complete,but the results are now published, since one of US is unable to carryon the work.E x P EB I YE NT A L.p-CresoZ-m-sulpho;L.ide, (OH*C,H,Me),SO.(Me : OH : SO = 1 : 4 : 3.)The sulphination of p-tolyl methyl ether with sulphurous acid andaluminium chloride yields the sulphoxide and a small quantity OGAZDAR AND SMILES. AHOMATIC IIYDROXY-SULPHOXIDES, 2249sulphinic acid, the sulphonium base, which is the final product ofnormal sulphination, being entirely suppressed (Smiles and LeRossignol, Zoc. cit.). On applying this method to p-cresol, similarproducts were obtained; but the yields of sulphoxide were poor, henceadvantage was taken of the stronger sulphinating power of thionylchloride.Although this reagent is apt to yield sulphonium saltsi f allowed to act too energetically, we find that by preserving suitableconditions excellent yields of the sulphoxide are obtained.Fifteen grams of powdered aluminium chloride were dissolved in an ice-cold solution of 20 grams of p-cresol in 50 C.C. of carbon disulphide, andthen 20 grams of thianyl chloride were gradually added. The mixturewas set aside in a desiccator, and, aftor the lapse of twenty-four hours,the greater portion of the reaction product-evidently a double salt ofthe sulphoxide with aluminium chloride-had separated in the form ofa yellow, viscous mass. During the next twenty-four hours a furthersmall quantity of this product separated ; the supernatant layer ofcarbon disulphide was then decanted, and the residue decomposedwith crushed ice.After being mixed with dilute hydrochloric acid,the mass was treated with a current of steam to remove carbondisulphide and unattacked cresol. After this operation, the contentsof the flask mere cooled, and the hard, granular mass was collected,dried, powdered, and then extracted with a small quantity of benzene,which removed coloured impurities.The yield of this product, which consisted of the almost puresulphoxide, was 20 grams, or about 85 per cent. of the theoretical. Itwas finally crystallised from hot glacial acetic acid, from which itseparated in colourless prisms. The pure substance melts and decom-poses at 185' :0*1706 gave 0.3977 GO, and 0.0836 H,O.C,,HI,O,S requires C = 64-12 ; H = 5.34 per cent.It furnishes a bright blue solution with concentrated sulphuricacid, but does not then condense with phenolic ethers, as do othersulphoxides of this group.Some derivatives of t h i s sulphoxide have been previously investigatedby Mr.Hilditch and one of the present authors (Proc., 1907,23,161),and, together with others since examined, they are now described indetail.Dibenzoyl-p-cresol sulphoxide was obtained from the parent substanceby the action of benzoyl chloride in alkaline solution. It is solublein hot alcohol, and separates from that medium in colourless plates,melting at 173' :C = 63.6 ; H = 5.4.0.1375 gave 0.3591 CO, and 0.0593 H,O.VOL.XCVII. 7 HC=71-23; H=4*8,C,,H,,O,S requires C = 71.46 ; H = 4.68 per cent2250 GAZDAR AND SMILES : AROMATIC HYDROXY-SULPHOXIDES.Di-p-cresol XuZphide, (OH* C,H,Me),S.The sulphoxide was reduced by the action of zinc dust on the hotsolution in glacial acetic acid. On mixing the filtered solution withwater, the sulphide separated as a colourless oil, which slowly solidified.After being recry stallised from dilute acetic acid, di-p-cresol sulphidewas obtained in colourless needles, which melted at 143' :0.1900 gave 0-4735 CO, and 0.0984 H20.Previous experiments have shown that the sulphoxide which isformed (Smiles and Le Rossignol, Zoc. cit.) by the interaction ofthionyl chloride and p-tolyl methyl ether contains the quadrivalentbulphur group in the ortho-position with respect to methoxyl, andthere can be little doubt that the hydroxy-derivative, which isprepared in a similar manner from p-cresol, has the same constitution,namely :C = 67.97 ; H = 5.7.C14H1402S requires C = 68.29 j H = 5.68 per cent.Further and independent evidence in support of this structure willbe adduced in a subsequent communication, but a t present it may beobserved that this is borne out by the behaviour of the substance onnitration.It is extremely easily attacked by nitric acid, two nitro-groups being a t first inserted; but attempts to induce furthernitration by intensifying the conditions of reaction result in theelimination of the thionyl group with formation of dinitrocresol.The most favourable conditions for nitration are as follows :Nitric acid (2.7 C.C.of D 1.5) is gradually added to a cooled solutionof the sulphoxide (5 grams; about two-thirds OF the theoreticalamount) in glacial acetic acid (100 c.c.). After three to four minutesa large bulk of water is added. The precipitate is collected andboiled with alcohol to remove soluble impurities, and the insolubleresidue finally recry stallised.Nitro-p-cresol sdphoxide is soluble in hot glacial acetic acid, andvery sparingly so in boiling alcohol; it separates fiom the lattermedium in lemon-yellow prisms, which melt at 214'. The scarletsodizcm salt is readily soluble iu water :0.1718 gave 0.3009 CO, and 0.0545 H,O.Cl,Hl,0,N2S requires C = 47.73 j H = 3.41 per cent.Action, of Hydrochlovic Acid.-Five grams of nitro-p-cresol sulphoxidewere suspended in about 50 C.C.of alcohol, which had previously beensaturated with dry hydrogen chloride at the atmospheric temperature.The mixture was heated to 100' in a sealed tube for four to fiveC = 47.7 ; H = 3.8OAZDAR AND SMILES : AROMATIC HYDROXY-SULPHOXIDES. 2251hours. Finally, the solid product was collected, washed with alcohol,and then crystallised from hot glacial acetic acid, from which itseparated in long, orange needles. The weight of the crude substancewas almost equal to that of the sulphoxide employed. When pure itdid not contain halogen :0.1305 gave 0.2382 CO, and 0.0410 H,O. C= 49.78 ; H=3*5.0.1392 ,, 0.2532 CO, ,, 0 0490 H,O. C=49.6; H= 3.9.C,,H1206N,S requires C = 50-00 ; H = 3.5 per cent.The analytical data and the properties of the substance show that itis nitro-p-wesol sulphide. This compound melts at 194O, and is solublein hot alcohol aod insoluble in water ; the sodium salt is deep red incolour.Other sulphoxides, which are described in the following pages,have been treated in a similar manner, and similar reactions have beenobserved ; but with less highly substituted aromatic nuclei chlorinationoccurs, and even elimination of the sulphur may take place. It maybe recalled that other oxygen derivatives of quadrivalent sulphur,namely, the sulphinic acids, are similarly reduced by mineral acids.pChlwopheno I Xzclphoxide.The sulphination of p-chlorophenol was effected with thionyl chlorideunder conditions similar to those described i n the preparation of thep-cresol derivative.The crude product, which was obtained in a yieldof about 70 per cent. of the theoretical, was purified by precipitationwith dilute hydrochloric acid from an alcoholic solution. The substancemas finally crystallised from dilute alcohol, from which it separated insmall, colourless prisms. It melts a t 202O, and is sparingly soluble inether or hot water, and readily so in cold alcohol :0.1487 gave 0.2580 00, and 0.0366 H,O. C=47.33; H=2.73.0,3538 ,, 0.331 AgCl ,, 0*2'780 BaSO,. C1=23.2; S = 10-8.Cl,H,0,Cl2S requires C = 47.52 ; H = 2.73 ; C1= 23-43 ;S = 10.56 per cent.p-ChZorophenoZ sutphoxide is soluble in concentrated sulphuric acid,the kolution being at first colourless, but rapidly assuming a brightblue colour, which is slowly discharged by the addition of phenetole,indicating the formation of a sulphonium salt.Is will be shown in asubsequent communication that the thionyl group in this sulphoxideoccupies the ortho-position with respect to the two hydroxyl groups ofthe phenolic nuclei, the substance having the structure :/\OH HO/\ cljj--so--v I ICl.7 ~ 2252 GAZDAR AND SMILES : AROMATIC HYDROXY-SULPHOXIDES.p-Chloro&rophenol Xulphoxide.When submitted to the action of nitric acid, this chloro-sulphoxidebehaves like the similarly constituted p-cresol sulphoxide ; two nitro-groups are readily absorbed, but further action of the acid results indecomposition. The dinitro-derivative was prepared in the followingmanner.The sulphoxide was suspended in about thirty times its weightof cold glacial acetic acid, and while the mixture was stirred, exactlythe calculated amount of nitric acid (D 1.42) was added, Stirring wascontinued until almost all the finely-divided solid had dissolved, thenthe mixture was rapidly filtered, and the dark reddish-brown filtrateswere immediately poured into a large bulk of water. The precipitatewas collected and extracted with alcohol ; finally, the insoluble portionwas recrystallised in small quantities from hot glacial acetic acid, Inthis way, p-chloronitrophenol sulphoxide is obtained in fine yellowneedles, which melt at 180-181°. It is insoluble in cold waterand sparingly soluble in boiling alcohol :0.1740 gave 0.2342 CO, and 0.0341 H20.C=36.7; H=2-1.C,,H,07N,C1,S requires C = 36-64 ; H = 1-53 per cent.p-Chlorophenol Sutphide.The sulphide may be obtained by the action of hydrochloric acidon the sulphoxide in alcoholic solution under conditions similar tothose described in the preparation of the nitrocresol derivative. Toisolate the substance, the mixture was poured into water, and, aftersome hours had elapsed, the solid was collected and recrystallisedseveral times from benzene, when it mas obtained in colourless leaflstswhich melted at 173-174'. It was found difficult completely topurify this substance, since it tenaciously retained sulphides of higherchlorine content. For comparison, the sulphide was prepared by thereduction of the sulphoxide in the usual manner with zinc dust andboiling acetic acid, and the product, after recrystallisation frombenzene, melted sharply at 174O and contained the requisite amount ofhalogen :C1= 24.79.C,,H802C1,S requires C1= 24-71 per cent.0.1280 gave 0.1288 AgC1.When mixed with this substance, the product obtained by theformer method retained the same melting point.o-Chlorophenol Xulphoxide.Sulphination of o-chlorophenol was conducted as with p-cresol andpchlorophenol j the yield of crude sulphoxide was approximately thSOME PHENOLIC DERIVATIVES OF P-PHENYLETHYLAMINE.2253same as that recorded in these cases, The coloured impurities wereremoved by tritiiration with cold glacial acetic acid, then the insolublematerial was collected, and finally purified by recrystallisation fromdilute alcohol, to which a little hydrochloric acid had been added,o-Chlorophenol sulphoxide forms fine colourless needles, which melt at195", and are soluble in most hot organic media :0.1504 gave 0.2600 GO, and 0.0383 H20.0.1535 ,, 0.1415 AgCl.Cl=22*8.0,2032 ,, 0.1485 BaSO,. S = 10.0.C,,H,O,Cl,S requires C = 47.52 ; H = 2.73 ; C1= 23.4 ; S = 10.5 per cent.The substance dissolves in concentrated sulphuric acid, forming ablue solution, from which the colour is removed by the addition of aphenolic ether, a sulphonium base being then formed. The action ofalcoholic hydrogen chloride on this substance is somewhat differentfrom that observed in the preceding cases. After the usual treatment,the reaction mixture mas submitted to distillation in a current ofsteam. The white, crystalline solid which separated from the distillatewas evidently dichlorophenol, for it melted at 43O and contained 43.4'per cent. of chlorine (calc., C1=43.55 per cent.). The non-volatileportion consisted of an oil which resisted all attempts at purification;it apparently consisted of a mixture of polychloro-sulphides.C= 47.21 ; H= 2.83.I n conclusion, we desire to express our thanks to the Research FundCommiftee of the Chemical Society for a grant which has defrayed theexpenses of these experiments.ORaANIC CHEMISTRY LABORATORY,UNIVERSITY COLLEGE, LONDON

ISSN:0368-1645    

DOI:10.1039/CT9109702248

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

SOME PHENOLIC DERIVATIVES OF P-PHENYLETHYLAMINE. 2253CCXXXVII.--Some Phenolic Dwivatives of P-Phenyl-et h y lamine.By GEORGE BARUER AND ARTHUR JAMES EWINS.~HYDROXY-P-PHENYLETHYLANINE, OH*C,H,*CB,*CH,*N.B,, whichis formed by the action of micro-organisms from tyrosine and fromproteins containing tyrosine, has been shown to have a pronouncedphysiological activity (Earger and Walpole, J. Physiol., 1909, 38, 343) ;it is, for instance, one of the active constituents of ergot extracts(Barger, Trans., 1909, 96, 1123).Since the effect of this base on the vascular system and on certainorgans is essentially similar to that of adrenaline (Dale and Dixon, J2254 BARGER AND EWINS: SOME PHENOLICPhysiol., 1909, 39, 25), to which phydroxy-P-phenylethylamine is alsochemically related, an examination of a considerable number ofsimilarly constituted amines was undertaken by Dale in order to traceas far as possible the connexion between physiological activity andchemical structure within the limits of this group (Barger and Dale, J.Physiol., 1910, 41, 19).The present paper deals with the synthesis of some of these amines.They were chosen for the following reasons :(1) Since the bactericidal action of phenol is greatly enhanced bythe introduction of a methyl group into the benzene ring (yieldingcresol), we prepared 3-methyl-4-hydroxy-P-phenylethylamine.Thepressor action of this base was found, however, to be only about onehalf as great as that of the parent substance.(2) One of the differences bet ween p-hydroxy-P-phenylethylamineand adrenaline (I) is that the former substance has only a singlephenolic hydroxyl group as compared with two in the latter substance.We therefore prepared 3 : 4-dihydroxy-P-phenylethylamine (11), whichwas found to be scarcely more active than the monophenolic aminealthough its N-methyl derivative, obtained by Pyman from an oxida-tion product of laudanosine (this vol., p.268), approximates muchmore closely to adrenaline.(3) Since in several cases the introduction of a second phenolichydroxyl group greatly increases the physiological activity of bases ofthis type, me wished to trace the effect of introducing yet anotherphenolic hydroxyl group, and for this purpose prepared 2 : 3 : 4-trih ydroxy-P-phenylethylamine (111) and o-aminoga ZZacet ophenone (I V).HO/'\HOI ICO*CH,*NH,OH HOHOf)HO\/CH,*CH,*NH, \/(111.) (IV. 1Both these bases were somewhat less active than the correspondingdihydroxy-bases (namely, 3 : 4 - dihydroxy - P - phenylethylamine ando-aminoacetylcatechol ).The close chemical relationship of the bases (I), (11), (111), and (IV) isfurther illustrated by the fact that they all give the colour reactionshitherto described as characteristic for adrenaline (I) (Ewins, J. Physiol,1910, 40, 317).The synthesis of 4 - h y d r o t t . y - P - m - t o l y ~ ~ t ~ y ~ a ~ ~ ~ ~ ~ started with m-tolyl-acetonitrile, and was completely analogous to t h a t of p-hydroxy-/3DERIVATIVES OF P-PHENYLETHYLAMINE. 2265phenylethylamine from phenylacetonitrile (Barger, Trans., 1909, 95,1123).3 : 4-Dihydroxy-p-phenylethylamine was obtained from its dimethylether, and has already been described by Mannich (Ber,, 1910, 43,196).The production of the pyrogallol bases (111 and IV) at first gaveconsiderable difficulty.The 2 : 3 : 4-trihydrosybenzaldehyde requiredfor (111) had to be prepared with anhydrous hydrogen cyanide accordingto Gattermann’s method. It was found impossible to obtain 2: 3 : 4-trimethoxy-P-phenylethylnmine from 2 : 3 : 4-trimethoxyphenylpropion-amide by Hofmann’s reaction, although this method was employed inpreparing the corresponding dimethoxy-base. We therefore had touse Curtius’s method, starting from 2 : 3 : 4-trimethoxyphenylpropionyl-h ydrazide.I n the case of o-aminogallacetophenone (IV) we found it quiteimpossible to isolate a pure substance when o-chlorogallacetophenonewas acted on by ammonia, although this method is employed technicallyin the case of w-chloroacetylcatechol ; the substance is destroyed tooreadily in alkaline solution.We therefore had recourse to an indirectmethod ; o-chlorogallacetophenone reacts readily with sodium azide,and from the o-triaxogallacetophenone, C6H2(OH)3*CO*CH2*N,, thusproduced the required amine is obtainable by reduction.I n the course of our work on this subject we have also pre-pared p-phenylethylmethylamine, C,H,-CH,*CH2*NH*CH3, of whichadrenaline is the trihydroxy-derivative. Two methods for preparingthis base will be mentioned, although it is not a phenolic amine, and wasrecently prepared by Johnson and Guest (Amer.Chem. J., 1909, 42,340) according to a third method (methylation of benzenesulphonyl-phenylethylamine and subsequent hydrolysis).EX PE a I Y ENTA L.p- Phenylethylmethylamine, C,H,*CH,* CH,*NH*CH,.As the direct methylation of P-phenylethylamine yields a quaternaryiodide, we condensed methylamine (in 33 per cent, aqueous solution)with phenylacetaldehyde by means of sodium hydroxide, and reducedthe crude condensation product, which separated out, with sodium andalcohol.A second, and more convenient, method consists in acting ona-chloro-P-phenylethane, C,H,*CH,*CH,CI (Barger, Trans, 1909, 95,2194), with an excess of a 33 per cent. alcoholic solution of methyl-amine at 100’ for several hours.The base thus obtained was distilled(b. p. 205O), and its hydrochloride was analysed. (Found, C1-20.7.Calc., C1= 20.4 per cent,)The base was isolated as the oxalate2256 BARGER AND EWINS: SOME PHENOLICPreparation of 4- Hydroxy-P-m-tolylethylamins,OH<\CW,*CH,*NH,. -/C'H,p-Nitro-m-tolylacetonitde, NO,/ \CH,.CN.-Ten grams ofm-tolylacetonitrile (Sehkowski, Molzatsh., 1888, 9, 854) were droppedinto 40 C.C. of nitric acid (D 1.5) at a temperature below - 5O. Theacid solution was then poured into water and extracted with ether.After washing with sodium carbonate, drying, and distilling, a fractionboiling at 201-205O/22 mm. was collected, which solidified, and oncrystallisation from ether and light petroleum melted at 52".Theyield was 80 per cent. of the theoretical :C= 61.2 ; H = 4.6.CH3-\/0.1584 gave 0.3554 CO, and 0.0665 H,O.p -Amino - m - tolylacetonitrile,CgH802N2 requires C = 61 *4 ; H = 4.5 per cent,NH,*C6H,Me*CH,*CN.-p - Nitro-m-tolylacetonitrile (19 grams) was dissolved in alcohol (240 c.c.), tin-foil (25 grams), and then gradually concentrated hydrochloric acid(120 c.c.) was added. The temperature was a t first kept below 60°,finally being raised to 100". After extraction with ether, the base wasdistilled, and 8.5 grams (60 per cent.) boiling at 175--185O/20 mm.were obtained. On crystallisation from benzene, the substance melteda t 8 7 O :0.1552 gave 0.4204 CO, and 000902 H,O.The hydrochloride, prepared by addiDg alcoholic hydrogen chloride to0.2082 gave 001620 AgCl.The oxalats melts a t 164-165' :0.1884 gave 24 C.C.N, (moist) at 20' and 768 mm.(CgH~oN2)2,H2C204 requires N = 14.7 per cent.p-Hydroxy-m-tolylacetonitrile, OH*C6H,Me*CH2*CN.-3*9 Grams ofsodium nitrite dissolved in ia little water were slowly added to a boilingsolution of 8.5 grams of the amino-compound dissolved in 200 C.C. ofdilute sulphuric acid (210 C.C. of water and 17 C.C. of concentratedsulphuric acid). On extracting the acid solution with ether, 2.5 grams(30 per cent.) of a substance were obtained, which distilled at162-164"/2 mm. and crystallised in the receiver. It crystailisesfrom benzene in leaflets melting a t 84" :C = 73.9 ; H = 6.5.C,H,,N, requires C = 74.0 ; H = 6.8 per cent.the ethereal solution of the base, melts at 247-248O :C1= 19.3.CSH,,N,,HC1 requires C1= 19.4 per cent.N= 14.7DERIVATIVES OF P-PHENYLETHYLAMINE. 22570.1526 gave 0.4093 CO, and 0-0807 H20.C = 73.1 ; H = 5.9.0-1718 ,, 14.2 C.C. Nz (moist) at 2 2 O and 760 mm. N= 9.4.C,H,ON requires C = 73.5 ; H = 6.1 ; N = 9.5 per cent.CH3L/ /-\CH2*CH2*NH2.-O*9 Gram 4-Hydroxy-/?-m-toZyZethyZamine, OHof p-hydroxy-rn-tolylacetonitrile yielded, on reduction with 4 grams ofsodium in boiling alcoholic solution, 0 -62 gram of a crude hydrochloride,which was crystallised by adding ether to its concentrated solution inalcohol. From this the free base was obtained; it crystallised fromxylene, and, after sublimation in a vacuum, melted at 132-133' :0*1290 gave 0.3364 CO, and 0-0910 H,O.CgHl,ON requires C = 71.5 ; H = 8.6 per cent.The hydrochloride was also analysed :0*1226 gave 0.0956 AgCl.C1= 19.3.C,H,,ON,HCI requires C1= 19.0 per cent.The dibenzoyl derivative crystallised from dilute alcohol in long,thin needles, melting a t 130-131°.The quaternary iodide, OH*C6H,Me*CH2*CH2*NMe,'T, was obtainedby boiling the base with a little methyl alcohol and a large excess ofmethyl iodide. It melts at 231-232O, and closely resembles hordeninemethiodide in solubility and other properties.4-Hydroxy-P-rn-tolylet hg lamine resembles p- hydroxy-P-phen yle thyl-amine in behaviour and derivatives.The physiological action of the former base is about one-half of thelatter. Both bases give Millon's reaction, but it is significant that,unlike phydroxy-P-phenylethylamine, the tolyl compound does notgive Morner's reaction (green coloration after heating with sulphuricacid and formaldehyde).It would appear that substitution in thephenolic ring prevents this reaction from taking place.C = 71-2 ; H = 7.9.Pveparation of 3 ; 4-Dihydro~-pphenyZ~thy~a~ine,HO<)HO\/C H,*CH,*NH,3 : 4-Dimethoxy-P-pheny IethyIamine was prepared from vanillinaccording to the method described in detail by Pictetand Finkelstein(Ber., 1909, 42, 1979), and 5.2 grams of the amine boiling at164-166'/13 mm. were obtained from 20.5 grams of homoveratricacid.The amine was hydrolysed by heating with ten parts of concentratedhydrochloric acid to 170° for two hours. The hydrochloride so obtainedcrystallised from 90 per cent.alcohol in glistening, almost colourles2258 BARGER AND EWINS: SOME PHENOLICplates, melting and decomposing at 240-2419 Yield, 45 per cent. ofthe theoretical. (Found, C = 50.6 ; H = 6.2. Calc., C = 50.7 ; H = 6.2per cent.The hydrobromide was obtained by heating the dimethoxy-amine to130' for two hours with ten times its weight of concentrated aqueoushydrobromic acid. The crystalline hydrobromide was obtained quitepure in the same manner as that employed in the preparation of thehydrochloride.0.1212 gave 0.0984 AgBr. Br = 34.5.CSH,,O2NBr requires Br = 34.2 per cent.The aqueous solution of the salts of 3 : 4-dihydroxy-/?-phenylethyl-amine gave an intense green coloration with ferric chloride.The quaternary chloride, C,H,(OH),*CH2*CH,*NMe,Cl, was pre-pared in order to compare its action with that of hordenine methiodide,OH-C6H4*CH,*CH2*NMe,I.The action of the two substances is verysimilar, like that of nicotine, and unlike that of adrenaline.3 : 4-Bihydroxy-~-phenyle~hyZtrimet~yla~nmonium chloride was ob-tained from 3 : 4-dimet hoxy -P-phenylethylamine. The quaternaryiodide obtained by treating the latter base with methyl iodide wastransformed into the chloride by digestion with silver chloride, andwas then hydrolysed by concentrated hydrochloric acid at 1 7 0 O . Onremoval of the latter, the residue crystallised from alcohol and ether,and melted at 201'.The salt crystallises in plates, melting a t 212O :Prepayation of 2 : 3 : 4-Trihydroxy-P-phelzylethylamine,C,H,(OH),*CH,*CH,*NH,.2 : 3 : 4-T&methoxybensaZdehyde, C6H,(OMe),*CH0.-This aldehydedoes not appear to have been described before, although F.Mauthner(Ber., 1909, 42, 188) has stated that it can be obtained from 2 : 3 : 4-trimethoxyphenylglyoxylic acid by the action of aniline, Themethylation of 2 : 3 : 4-trihydroxybenzaldehydo, which was preparedfrom pyrogallol and anhydrous hydrocyanic acid according to Gatter-mann and Kmbner's method (Ber., 1899, 32, 281), was carried out inan atmosphere of hydrogen by the method employed by Perkin andRobinson (Trans., 1907, 91, ,1079) for the preparation of Vera-traldehyde from vanillin, Twenty-five grams of 2 : 3 : 4-trihydroxy-benzaldehyde were dissolved in 80 C.C. of methyl alcohol, and to thissolution was added 24 grams of sodium hydroxide dissolved in theminimum quantity of water.The solution became very dark brownin colour. Eighty grams of methyl sulphate were then added, andwhen the vigorous reaction had nearly subsided, a further 66 grams insmall quantities alternately with small quantities of sodium hydroxidewere added a t such a rate that a vigorous reaction was maintainedDERIVATIVES OF &PHENYLETHYLAMINE. 2259The mixture was kept for half an hour, and then poured into 500 C.C.of water. An oil separated, which was extracted by means of ether,and, after drying and removal of the solvent, the residue was distilled,18.5 Grams of a colourless liquid, boiling at 168-170°/12 mm., werethus obtained. The distillate solidified after some time to a crystallinemass of long, thin needles, melting at 30" :0.1840 gave 0.4126 CO, and 0.1020 H,O.C = 61.1 ; H = 6.2,CloH1204 requires C = 61.2 ; H = 6.1 per cent.2 : 3 : 4-Trirnethoxy-/3-phertylpropionic Acid,C,H,(OMe),*CH,*CH,*CO,H.Twenty grams of 2 : 3 : 4-trimethoxybenzaldehyde were dissolved in35 grams of ethyl acetate, and the solution added to 3.3 grams offinely divided sodium contained in a large flask provided with a refluxcondenser. A vigorous reaction ensued. The product was kept forone hour, and then a solution of 14 grams of sodium hydroxide inmethyl alcohol was added. After the reaction had ceased, 250 C.C. ofwater were added. The alcohol was then removed by evaporation ona water-bath, water being added from time to time to avoid undueconcentration.The alkaline solution was then reduced by theaddition of 500 grams of 24 per cent. sodium amalgam in smallportions, concentrated hydrochloric acid being added from time to timeto neutraliso the excess of sodium hydroxide formed in the reaction.The resulting solution was filtered, and acidified with hydrochloricacid. A yellow oil separated, which slowly erystallised. The acidwas purified by distillation under diminished pressure (it boils at200-203°/2 mm.) and subsequent crystallisation from ether and lightpetroleum, from which it separated in clusters of prisms, melting at76". Yield, 50 per cent. of the theoretical :0.2150 gave 0.4722 CO, and 0.1282 H,O. C = 69.9 ; H = 6.6.CI2Hl6O5 requires C = 60.0 ; H = 6.7 per cent.Ethyl 2 : 3 : 4-Trimethoxy-~-phenylpropionat~,C,H2( OMe),*CH,*CH,* C0,Et.The acid obtained as above was converted into the correspondingethyl ester by dissolving in five times its weight of 5 per cent.alcoholichydrogen chloride and boiling under reflux for six hours. The alcoholand hydrochloric acid were evaporated off, and the residue wasdistilled. The ester boils at 200-201°/20 mm. Yield, 70 per cent. ofthe theoretical :0.2074 gave 0.4797 CO, and 0.1390 H,O. C = 63.1 ; H = 7.4.C1,H,oO, requires C = 62-7 ; H = 7.4 per cent2260 SOME PHENOLIC DERIVATIVES OF ,&PHENYLETHY LAMINE.2 ; 3 : 4-Trimethoxy-~-phenylpropion~Zhydrazide HydrochZoride,C,H2(OMe),*CH2*CH2*CO~NH*NH2,HCl,Two grams of the above ester mere gradually added to 0.6 gram ofboiling hydrazine hydrate.Solution was complete a t the end of onehour, and the solution was boiled under reflux for several hours longer.The excess of hydrazine was removed by evaporation in a vacuum oversulphuric acid. The syrupy residue could not be crystallised, but ondissolving in alcohol and adding a little alcoholic hydrogen chloride acrystalline precipitate separated, which was increased by the additionof ether. The hydrochloride thus obtained mas recrystallised from98 per cent. alcohol, separating in the form of hexagonal plates, whichmelted a t 155’ :0,1679 gave 0.3020 CO, and 0.0947 H20.The solution of this salt readily reduced ammoniacal silver in theCe49.0 ; H = 6.3.C,,HI,O,N,C1 requires C = 48.8 ; H = 6.5 per cent.cold, and Fehling’s solution on boiling.2 : 3 : 4-~rihydroxy-/3-phenylethylamine Hydroch Zoride,C,H2(0H),*CH2*CH2*NH,,H CI.The hydrazide obtained as described above was diazotised at Oo.The crude azide, obtained by extraction with ether, was converted intothe corresponding urethane derivative by boiling in absolute alcoholicsolution for twelve hours under reflux.The alcohol was then distilledoff, and the residue hydrolysed by heating in a sealed tube withconcentrated hydrochloric acid to 1 70-180° for three hours. Thevery dark-coloured contents of the tube were evaporated to dryness,dissolved in a little water, boiled with animal charcoal, filtered, andthe solution evaporated nearly to dryness. From the dark brownsyrupy product, crystals slowly separated.These mere pressed on aplate, and recrystallised from absolute alcohol by addition of ether.The crystals, which melted a t 162-163’, were still dark brown incolour. The aqueous solution gives with ferric chloride a deep purple-brown coloration, which rapidly fades :0*1000 gave 0*0700 AgC1. C1= 17-32.C8H,r0,NCl requires C1= 17.35 per cent.HO/\KOPreparation of o-Amilzogallucetop~~one, HOI ‘CO*CH2*NH2. \/o-Tria~ogallacetophanone, C6H2(OH),*CO*CH2*N,.-Seven grama ofo-chlorogallacetophenone, prepared according to Nencki’s methoTHE FORMATlON AND REACTIONS OF IMINO-COMPOUNDS. 2261(J. Buss. Phy8. Chem, Xoc., 1883, 25, 182), were dissolved in50 C.C. of hot water, and a hot solution of 2.5 grams of sodiumazide in a little water added, On cooling, a crystalline solidseparated. This was collected and recrystallised from xylene, whenrhomb-shaped plates, melting at 155O, were obtained. Yield, 50 percent. of the theoretical :0,2460 gave 44.2 C.C. N, (moist) a t 19O and 758 mm. N = 20.7.C,H70,N, requires N = 20.1 per cent.o- A rninog allacet ophenone Hydrochloride,C,H,( OH),*CO* CH,*NH,, HCl.-Five grams of w-triazogallacetophenone were dissolved in absolutealcohol. Ten grams of tin-foil were then placed in the liquid, and60 C.C. of concentrated hydrochloric acid added in small portions. Asreduction proceeded, the hydrochloride of the base separated out insmall, rectangular plates. The yield was 1.2 grams, or 25 per cent. ofthe theoreticalFor analysis, the salt was recrystallised from alcohol and ether, whenit melted at 259-260' :0.1916 gave 10.8 C.C. N, (moist) at 17O and 754 mm.0.1275 ,, 0*0838 AgC1. Cl= 16.2 ; N= 6.5.C,H,,O,NCl requires N = 6.4 ; C1= 16.1 per cent.The salt is readily soluble in water ; i t aqueous solution darkens onkeeping, and with very dilute ferric chloride solution gives a dirtygreen coloration, which rapidly changes to a brownish-yellow.THE WELLCOME PHYSIOLOGICAL RESEARCH LABORATORIES,HERNE HILL, S.E

ISSN:0368-1645    

DOI:10.1039/CT9109702253

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

THE FORMATlON AND REACTIONS OF IMINO-COMPOUNDS. 2261CCXXXVIII. - 17he Formation and Reactions o jImino-compounds. Part XIV. The Formationof a- Hydrindone and its Derivatives.By ALEC DUNCAN MITCIIELL AND JOCELYN FIELD THORPE.SOME time ago (Trans., 1908,93,165) it was shown that P-hydrindoneand some oE its derivatives could be derived from P-imino-a-cyano-hydrindene (11), a substance which is formed in quantitative yieldwhen an alcoholic solution of o-phenylenediacetonitrile (I), contain-ing a trace of sodium ethoxide, is warmed.CH,*CN >CXH --+ C,H,<CH2>C0(1.1 (11.1 f i - ~ y a ~ i n a ~ n e .C6H'SCIF,.CN -+ C6H4<%t&j aH2262 MITCHELL AND THORPE: THE FORMATION ANDThe present paper deals with a similar reaction by which a-hydrindoneand its derivatives can be produced through the imino-compound.a-Hydrindone was originally prepared by Gabriel and Hausmann(Bey., 1889, 22, 2018), and was subsequently investigated byHausmann (ibid., p.2020). Gabriel and Hausmann prepared theketone by condensing o-cyanobenzyl chloride (111) with the sodiumcompound of ethyl acetoacetate, when a compound, which theyconsidered to be ethyl o-cyano-P-phenylpropionate (I V), was formed,and this substance, on treatment with concentrated hydrochloricacid, passed into a-hydrindone (V).(111.) (IV.) (V. )Hausmann (Zoc. cit.) subsequently found that when ethyl sodio-malonate was used in this reaction in place of ethyl sodioacetoacetate,the same substance (IV) was produced.The formation of a-hydrindone from ethyl o-cyano-P-phenylpropionateon treatment with concentrated hydrochloric acid was explained on theassumption that o-carboxy-P-phenylpropionic acid (VI) is first formed,which then decomposes into water, carbon dioxide, and a-hydrindone,thus :(VI.1This is also the explanation advanced by Aschan (Chemie derAZicykZischen Verbindumgen, p. 1028), who remarks that Konig hasshown (Anrtctlen, 1893, 275, 341) that o-csrboxy-P-phenylpropionicacid passes on distillation into a-hydrindone. It must be remembered,however, that the production of a-hydrindone from o-carboxy-P-phenyl-propionic acid in this manner takes place at a high temperature, thatis to say, under :conditions very different from those which convertethyl o-cyano-/3-phenylpropionate into this ketone.It therefore seemedto us unlikely that the mechanism of this reaction, as recorded above,could be correct, and we consequently decided to seek for some otherexplanation more in accordance with the experimental facts.It has been already mentioned that, according to the observation ofHausmann, the condensation of o-cyanobenzyl chloride with both ethylsodiomalonate and ethyl sodioacetoacetate yields the same product,namely, ethyl o-cyano-P-phenylpropionate (IV). It is evident, there-fore, that in the first condensation a carbethoxyl group, and in thesecond condensation an acetyl group, must have been eliminated duringthe process of the condenaation.Neither Gabriel nor Hausmann seems:to have remarked on this, butREACTIONS OF IMlNO-COMPOUNDS. PART SIV.2263in the light of recent investigation on the formation of five-ring imino-compounds, the fact possessed for us some significance.Thus we have always found that when the five-carbon ring is formedthrough the imino-group, the formula of the product does not allow oftwo carbethoxyl groups, a nitrile group and a carbethoxyl group, or anacetyl group and a carbethoxyl group, being attached to the same carbonatom; an example of this, which bears closely on the present instance,being the transformation of the open-chain compound (VII), which isformed by the condensation of ethyl sodiomalonate and ethyl 1-cyano-cydopropane-1-carboxylate into ethyl 2-iminocyclopentane-1 : 3-dicarb-oxylate (VIII) (this vol., p.1002).(VII.)QH,*CH(CO,Et) CH2* UH( C0,>C:NH.The elimination of a carbethoxy-group in Hausmann’s condensationsuggested therefore the closing of the five-carbon ring, in whichcase the reaction would have proceeded as follows :(VIII.)or in the case of ethyl sodioacetoacetate as follows :C,H4<E&C1 + CHAcNa*CO,Et -+CNcAH4<CXI,*CHbc*C0,Eti i- NaC1*+ EtOH -+ CNC6H4%H,*CHAc*C0,EtC 6 H 4 < ~ & ~ ~ > C H * C O z E t + Me*CO,Et.In these circumstances the compound described by Gabriel andHausmann as ethyl o-cyano-P-phenylpropionate would be ethyl 1-imino-hydrindene-2-carboxylate (IX), and its transformation into a-hydr-indone by the action of concentrated hydrochloric acid could be readilyexplained thus :C,H4<~&~H&CH*C0,Et -+ C6H4<Co->CH*C02Et CH2 --2264 MITCHELL AND THORPE: THE FORMATION ANDInvestigation proved that this view of the formation of a-hydrindonewas correct, and that the compound described as ethyl o-cyano-p-phenyl-propionate behaved in every way as an imino-compound of formula (IX).Before this fact could be definitely proved it was necessary, however,t o thoroughly study the condensation of o-cyanobenxyl chloride withthe sodium compounds of both ethyl malonate and ethyl acetoacetate,and as, at the same time, it was thought advisable, for reasons giveniater, to investigate the corresponding condensation with ethyl sodio-cyanoacetate, it is best, for the sake of comparison, to describe thethree condensations separately.(1) The Condensation of o-Cyanobenxyl Cht?oride with the XodiumCompound o j EthylMa1onate.-In effecting this condensation, Hausmannused equivalent quantities of sodium dissolved in alcohol, and of thetwo reacting substances.Hs found that, mixed with the chief productof the condensation (the so-called ethyl o-cyano-P-phenylpropionate), aconsiderable quantity of a product melting at 8 6 O was also formed.This he showed to be ethyl di-o-cyanobenzylmalonate (X),(CN*C,H,*CH,),C(CO,Et),,(X. )which had been formed by the condensation of two molecules of0-cyanobenzyl chloride with one molecule of ethyl malonate.Hausmann separated the two products by treating the mixture withcold concentrated hydrochloric acid, in which the supposed ethylo-cyano-p-pheny lpropionate dissolved, and could be obtained on mixingthe hydrochloric acid filtrate with water.Now it is obvious that the formation of the derivative (X) musthave taken place in the following manner :(1) C?N*C),H,*CH,Cl + CHNa(CO,Et), -3CN~C,H,~CH,~CH(CO,Et), + NaCI.(2) CN*C6H,*CH2*CH(C0,Et), + CHNa( CO,Et), -+ON*C,H4*CH2GNa(C0,Et), + CH,(CO,Et),.(3) CN*C6H,*CH,*CNa(C0,Et), + CN*C6€€,*CE,CI -+( CN*C6H40CH,),C(C0,Et)2 + NaCl.That is to say, the initial condensation product of o-cyanobenzylchloride and ethyl sodiomalonate must be the normal product ofthe formula CN*C,H,*CH,=CH(CO,Et),, and the elimination of acarbethoxyl group must therefore have taken place subsequent toits formation,Our previous experiments on this point show that the elimination ofthis group is always effected by the action of free sodium ethoxide, orof some sodium derivative dissociating in alcoholic solution, and henceit seemed to us likely that by preventing, so far as possible, the presencREACTIONS OF IMINO-COMPOUNDS.PART XTV. 2265of excess of the sodium derivative of ethyl malonate during the processof the condensation the elimination of this group might be avoided.This proved to be the case, for it was found that when an alcoholicsolution of ethyl sodiomalonate containing a slight excess of ethylmalonate was added slowly to a hot alcoholic solution of o-cyanobenzylchloride, the product of the reaction did not become solid on beingpoured into water, but remained as a heavy oil at the bottom of theliquid.This oil proved to be the normal condensation product, namely,ethyl o-cyanobenzylmalonate, CN*C,H,*CH,*CH(CO,Et),, and it wasfound that when an alcoholic solution of this substance containing atrace of sodium ethoxide was warmed, a carbethoxyl group was at onceeliminated as ethyl carbonate, and the product described by Hausmannas ethyl o-cyano-P-phenylpropionate was formed.Subsequent investi-gation proved conclusively that this product is ethyl 1 -iminohydrin-dene-2-carboxylate (IX), and that its formation in the manner des-cribed above is represented by the equation :UX.1The proof of the constitution of this substance is as follows : Whena solution of the imino-compound in alcohol is mixed with rather morethan the quantity of concentrated hydrochloric acid necessary tohydrolyse the C:NH-group to carbonyl and the solution is warmed,ammonium chloride separates, and the solution on dilution yields an oilwhich boils a t 185'/20 mm., and which gives in alcoholic solution anintense violet coloration with ferric chloride.This oil, which is withoutdoubt ethyl 1 -hydrindone-2-carboxylate (XI),gives a well defined phenylhydrazone and semicarbazone, the samephenylhydrazone being also formed from the imino-compound (IX)when it is boiled in acetic acid solution with phenylhydrazineacetate.The imino-compound is, as Gabriel and Hausmann showed, readilysoluble in concentrated hydrochloric acid, and is precipitated on addingwater. It is not, however, completely unchanged by this process, sincea quantity, depending for amount on the length of time it is left incontact with the strong acid, is converted into the ketone. The processof conversion at the ordinary temperature is very slow, and the usualmethod adopted in other cases, of pouring the concentrated hydro-vm. XCVII.7 2266 MITCHELL AND THORPE: THE FORMATlON ANDchloric solutiori, into hot water and cooling, converts only a smallquantity of the imino-compound into the ketone. It is evidenttherefore that ethyl l-iminohydrindene-2-carboxylate is a tautomericamino-imino-compound reacting in the two forms :but thiit it has only a short imino-phase.E thy1 1-hydrindone-2-carboxylate (XI) is readily soluble in diluteaqueous potassium hydroxide, but i t is only slowly extracted from itssolution in ether by means of aqueous sodium carbonate solution.Both the potassium and sodium salts are sparingly soluble inexcess of the alkali, and can be readily isolated in a pure condition.When the potassium salt (XII), either in the soluble or insoluble form,is boiled in alcohol with methyl iodide, the C-methyl derivative (XIII)is obtained as sole product, and no trace OF the corresponding O-methylether could be detected :c6H4<Et7cK* CO,Et -+ C,H4<Egi>CMe*C0,Et(XII.) (XIII.)The C-methyl derivative readily yields the corresponding 2-methyl-l-hydrindone when distilled in a current of steam from dilute sulphuricacid.a process which is complete, owing to there being no tendency forthe P-alkyl derivatives of a-hydrindone to undergo intramolecular con-densation analogous to the formation of anhydro-bis-a-hydrindone(Trans., 1897, 71, 241) from a-hydrindone. The direct formation ofethyl l-iminohydrindene-2-carboxylate in the original condensation is,we find, best effected by working in the manner described above untilthe reaction is complete, and then, by adding excess of sodium ethoxide,to convert the open-chain compound into the hydrindene ring.Thecompound CN*C,H,*CH,*C(CO,Et),*C A,*C,H,=CN, which is formed bythe condensation of two molecules of o-cyanobenzyl chloride with onemolecule of ethyl malonate, is so readily produced that if the conden-sation is effected in the usual way, the product consists for the most partof the more complex derivative.(2) The Condensation of Ethyl Xodioacetoacetate and o-CyanobenxylChZoride.-It is hardly necessary in this condensation to take anyprecautions t o prevent the formation of the derivativeCN*C,H,*CH,* CAc( C0,Et) CH2*C,H4 *CN,as under the ordinary conditions very little of it is formed.If, how-ever, the method described in the experimental portion is used, thenormal product (XII) can be readily isolated, and this compound oREACTIONS OF IMINO-COMPOUNDS. PART XTV. 2267treatment with a trace of sodium ethoxide passes quantitatively intoethyl acetate and ethyl 1-iminohydrindene-2-carboxylate, thus :+ EtOH -+ CNCaH4<CH,*CHAc*C0,EtC6H4<E&y>cH. C0,E t + Me C0,Et.For the rapid preparation of this imino-compound in quantity thiscondensation produces the best results, the best method being to addan alcoholic solution of ethyl sodioacetoacetate containing a slightexcess of sodium ethoxide to a hot alcoholic solution of the chloride.( 3 ) The Condensation of Ethyl Sodiocyanoacetate and o-CyanobenzylChloride.-The main object of investigating this condensation was tocompare the derivatives of a-hydrindone with those of /?-hydrindone inorder to ascertain whether the phenomenon of '' steric inhibition "which was so marked in the case of the P-compound substituted inthe a-position applied also to the a-compound substituted in theP-position.It has been found as regards the derivatives of P-hydrindone and itsimino-derivative (Trans., 1908, 93, 165), that the presence of certaingroups on the a-carbon atom causes the compounds to react as trueamino-derivatives, whereas certain other groups on this carbon atomcause the imino-form to be stable, and that this occurs irrespective ofthe acidity of the groups which we have hitherto shown to be thedetermining factor in deciding the amino- or imino-structure of acompound of this type.Thus the compound of formula (XIIIa)evidently had the imino-structure, or rather exhibited amino-imino-tautomerism with a long imino-phase, whereas when the cyano-groupwas displaced by the less negative carbethoxyl group, the compound,instead of showing amino-imino-tautomerism with a longer imino-phase, as it should have done, behaved as a true amino-compoundof formula (XIV) :(XIIIa.) (XIV.)It seemed of interest thereFore to compare the corresponding deriv-atives of a-iminohydrindene of formuh (XV) and (XVI)(XV.1 (XVI.)in order that a direct comparison might be made between the twoseries.The condensation of o-cyanobenzyl chloride with the sodium7 1 2268 MITCRELL AND THORPE: THE FORMATION ANDcompound of ethyl cyanoacetate, if carried out in the usual may, leadsto the formation of the compoundCN *C,H,* CH,*C(CN) (CO,Et)* CH,* C,H,* CNto the extent of 80 per cent.of the theoretical amount, and only asmall quantity of ethyl 1-imino-2qanohydrindene (XV) is produced.If, however, the precaution is taken of adding an alcoholic solutionof the sodium salt of ethyl cyanoacetate t o a hot alcoholic solutionof o-cyanobenzyl chloride, a considerable yield of the normal condensa-tion product (XVII) can be obtained, and this substance on treatmentwith sodium ethoxide passes at once into 1-imino-2-cyanohydrindeneand ethyl carbonate in accordance with the scheme :+ EtOH -+ ONC6H4<CH,*CH( CN) C0,Et(XVII.)C,H,<Z&:E?>CH*CN + CO(OEt),.A comparison of 2-imino-1 -cyanohydrindene (XIII) with l-imino-2-cyanohydrindene (XV) showed that these compounds did not possessany essential points of difference beyond what was to be expected fromtheir structure.Thus the imino-group of 1-imino-2-cyanohydrindeneis between the negative phenylene group and the nitrile group,whereas in the case of 2-imino-1-cyanohydrindene the negativeinfluence of the phenylene group would be less pronounced.Conse-quently it might be anticipated that whilst both compounds wouldbe tautomeric amino-imino-compounds, the 1-imino-derivative wouldpossess a longer amino-phase than the 2-imino-derivative.This anticipation is borne out by the experimental facts, forwhereas 1 -imino-2-cyanohydrindene, with its long amino-phase, dis-solves readily in concentrated hydrochloric acid, forming a salt which,on the addition of water, is dissociated regenerating the amino-compoundmixed with only a small quantity of the corresponding ketone, 2-imino-1 qanohydrindene does not dissolve in concentrated hydrochloric acid,but when warmed with the acid is converted almost completely intothe ketone. I n other words, the rate of hydrolysis of the 2-imino-derivative is very much quicker than that of the 1-imino-derivative.The two compounds therefore serve as admirable ex.amples of theinfluence of negative groups on the predominance of the amino- orimino-phase i n compounds exhibiting amino-imino-tautomerism.When the two carboxylic esters of formuh (XVIII) and (XIX)(j0H4<~&~f~>C*C02Et and C0H4<CH(Co2Et)>C: CH2- NH(XVIII.) (XIX.)are compared, a marked difference is at once apparent.T t has been already shown that ethyl 2-iminohydrindene-l-ca1-bHEACTIONS OF IMLNO-COMPOUNDS.PART X LV. 2269oxylate (XIX) is a true amino-compound, which can be hydrolysedto the corresponding acid by means of hydrochloric acid without thenitrogen group being affected. Subsequent experiments showed thatthis behaviour was exhibited by other compounds having groups oflarge molecular volume attached to the 1-carbon atom, and hence itwas suggested that the presence of a group of more than a certainvolume did not permit of the attachment of the hydrogen atom to the1-carbon atom.In other words, the compound ceased, under theseconditions, to react in one of its tautomeric forms.The examination of the behaviour of ethyl l-iminohydrindene-2-carboxylate (XVIII) under similar conditions showed that, althoughthe substitution of the carbethoxyl group for the nitrile groupincreased the amino-phase of the compound, that is to say, increasedthe length of time required for the hydrolysis of the compound to theketone, yet it still exhibited well-defined amino-imino-tautomerism, andits hydrolysis to the ketone by acids was always completely effected,It is, of course, evident that as the carbethoxy-group possesses lessnegative properties than the nitrile group, the reverse should be thecase, and it therefore follows that there must be a certain degreeof steric hindrance attaching to the 1-carbon atom, but to a very muchless extent than to the %carbon atom.An explanation of this factis aEorded by the consideration that the 1-carbon atom of ethyl2-iminohydrindene-1-carboxylate is attached t o both the phenylenegroup and the carbethoxyl group, whereas the 2-carbon atom of ethyl1-iminohydrindene-2-carboxylate has only the carbethoxyl attachedto it.When the oxygen derivatives (XX) and (XXI) are compared, certainpoints of difference are also observed. Thus it has: been shown that1-cyano-2-hydrindone (XXI) yields a methoxy-derivative (XXII) whenalkylated by the usual etherifying agents, but that when methylatedby means of sodium methoxide and methyl iodide it yields the C-methylderivative (XXIII).With 2-cyano-1 hydrindone (XX) the increasednegative character of the compound due to the proximity of thephenylene group is apparent, and the action of sodium methoxideand methyl iodide leads t o the formation of the methoxy-derivative(XXIV) only22'10 MITCHELL AND THORPE: THE FORMATION ANDAs considerable quantities of the compounds containing twoequivalents of o-cyanobenzyl chloride had accumulated during thepreparation of the simpler products formed in these condensations, weinvestigated their properties.The cyano-derivative (XXV) formedin the ethyl cyanoncetate condensation is readily hydrolysed by dilutealkali, yielding an alkali salt, from which the acid (XXVI) is obtainedby the action of mineral acids, When heated at lSOo, this substanceCN*C,H,*CH,*C(CN)(Co,Et)* CH,*c6H4*cN(XXV.)ONm C,H,* CH,* c( CN) (C0,H) cH2*c6H, * ON(XXVI.)CN*C6H,*cH2*CH( CN)*CH,*C,H,*CN(XXVII.)CO,H*G,H,*CH,* CH( CO2H)*CH2*C6H4*CO2H(XXVIII.)eliminates carbon dioxide and passes into the trinitrile (XXVII).When completely hydrolysed, the nitrile is converted into the tri-carboxylic acid (XXVIII), a compound which is identical with thatformed by the complete hydrolysis of the condensation products(XXIX) and (XXX) formed in the ethyl malonate and ethyl aceto-acetate condensations respectively.The constitution of these morecomplex compounds is therefore clearly established.CN*C6H, CH2* C( CO,Et),* CH2* C6H4* CN(XXIX.)CN * C6H,* CH,*CAc( C0,Et) *CH,= C,H,- CN(XXX.)EXPERIMENTAL.Etl.?) o-Cyanobenxyt?ma~onate, CN*C6H4*CH,*CH(C0,Et),.This substance can be prepared in quantity by the condensation ofethyl sodiomalonate with o-cyanobenzyl chloride if care is taken not tohave free sodium ethoxide present at any time during the course ofthe condensation. In order to effect this, i t is necessary to add analcoholic solution of the sodium compound of ethyl malonate to a hotalcoholic solution of the chloride, that is to say, in the reversemanner to that usually adopted in these condensations.The con-ditions found most favourable were as folbws : 2.2 grams of sodiumwere dissolved in 50 C.C. of alcohol and mixed with 16 grams of ethylmalonate, the warm solution being then slowly added to a hot solutionof 15 grams of o-cyanobenzyl chloride dissolved in the requisiteamount of alcohol. The reaction was allowed t o proceed by its ownheat, and was completed by heating on the water-bath for five minutes,when the solution was found to be neutral. Water was then added,and the alcohol and unchanged ethyl malonate separated by distillatioREACTIONS OF IMINO-COMPOUNDS. PART XIV. 227 1in a current of steam, the heavy, non-volatile oil being subsequentlyextracted by ether.The residue which remained after evaporating theether yielded a large fraction, boiling at 213'/20 mm., consisting of aviscid, colourless oil :0.1958 gave 0.4722 CO, and 0.1080 H,O.C,,H,704N requires C = 65.4 ; H = 6.2 per cent.The ethyl salt is unchanged by cold concentrated hydrochloric acid,and its open-chain structure is proved by the fact that when boiled fora long time with dilute sulphuric acid, i t is slowly hydrolysed, and thesolution on cooling deposits a ci-ystalline acid, which, when recrystal-lised from water, yields long needles, melting at 166'. (Found,C = 61-72 ; H = 5.3.C = 65.77 ; H = 6.13.Calc., C = 61.8 ; H = 5.2 per cent,)The acid is therefore o-carboxy-j3-phenylpropionic acid,C0,H C,H,*CH2* CH,*CO,H.During the fractionation of ethyl o-cyanobemylmalonate a smallquantity 6f lower boiling material was obtained, which solidified aftersome time, and, on examination, proved to be ethyl l-iminohydrindene-2-carboxylate (see p.2273). There was also a small amount of higherfraction boiling at about 300'/20 mm., which also solidified, and provedon investigation to be ethyl di-o-cyanobenzylmalonate (see p. 2280).Ethyl l-lminohydrindene-2-carbox~late, C,H,<:$>CH* C0,Et.This substance may be prepared in one of two ways, namely :(1) By the Action of Alcoholic Sodium Ethoxide on Ethyl o-Cyanobenxyl-ma1onate.-This method, which gives a quantitative yield of the imino-compound, can be carried out as follows : 10 grams of the ethyl saltare diluted with twice its volume of alcohol, and 1 C.C.of a solution of1 gram of sodium in 12 C.C. of alcohol is added. The solution, whichbecomes appreciably warm, is kept for fifteen minutes, when it iswarmed on the water-bath for five minutes and then poured into anequal volume of water. The crystals which separate are thencollected and recrystallised from dilute alcohol.The mother liquor from the crystals was extracted with ether, andthe residue, af t u r evaporating the ether, carefully fractionated underthe ordinary pressure. A fraction boiling a t 126-12'7' was ulti-mately obtained, which analysis showed to be ethyl carbonate.(Found, C = 50.65 ; B = 8.6.(2) By the Direct Condensation of Ethyl Sodiomalonate and o-Cyano-belzzyl Chloride.-This method was that used by Gabriel and Hausmann,but under the conditions employed by them, we find that the greaterportion of the product consists of ethyl di-o-cyanobenzylmalonate, andonly a small yield of the imino-compound can be obtained.It is men-Calc., C = 50.8 ; H = 8.5 per cent.2272 MITCHELL AND THORPE: THE FORMATION ANDtioned later (p. 2279) that the best method for preparing this imino.compound in quantity is by employing the sodium compound of ethylacetoacetate instead of ethyl sodiomalonate in the condensation, becausein that case very little of the di-derivative is formed. A good yield ofthe imino-compound can, however, be obtained from ethyl malonate ifthe conditions described in the preparation of ethyl o-cyanobenzyl-malonate (p.2270) are closely followed, and, as soon as the con-densation mixture has become neutral, a small quantity of alcoholicsodium ethoxide is added, and the heating continued for five minuteslonger. When the product obtained in this way is poured into water, itwill be found that the whole of the dicarboxylic ester has been con-verted into the imino-compound and ethyl carbonate, and that it willdeposit a large quantity of oil which will solidify on scratching. Thissolid, which consists of the imino-compound mixed with some ethyldi-o-cyanobenzylmalonate, can be separated by the method used byGabriel and Hausmann, that is, by dissolving the imino-compound inconcentrated hydrochloric acid and filtering the solution from theundissolved di-derivative.On diluting the filtrate, a certain amountof the imino-compound separates in the crystalline form, but theseparation is by no means complete, as the substance is appreciablysoluble in dilute hydrochloric acid. I n order to obtain the wholeamount, it is necessary to extract the diluted acid solution with ether.Ethyl 1 -iminohydrindene- 2- carboxylute crystallises from dilutealcohol in colourless needles, which melt a t 98'. It gives no colorationwith ferric chloride :0.1923 gave 0.4970 CO, and 0.1060 H,O.C12H1302N requires C = 70.9 ; H = 6.4 per cent.The mother liquor from the recrystallisation of the imino-compoundgives an intense blue coloration with ferric chloride, showing that thetreatment with hydrochloric acid had converted some of it into thecorresponding ketone.When treated in hot acetic acid solution withphenylhydrazine acetate it yields the same hydrazone, melting atlOl*S0, as that derived from the ketone (p. 2273). It is insoluble inaqueous potassium hydroxide, and is only slowly hydrolysed on boilingwith this reagent.Action of Nitrous Acid.-When the imino-compound is dissolved inconcentrated hydrochloric acid and mixed when very cold with excessof sodium nitrite solution, an oil is precipitated which solidifies aftersome time. When this substance is recrystallised from alcohol, it isobtained in brilliant yellow leaflets, which melt at 163" with vigorousdecomposition and charring.C = 70.49 ; H = 6-10,Analysis points to the formulREACTIONS OF IMINO-COMPOUNDS. PABT n v .2273but the position of the nitroso-group in the ring is uncertain :0.1765 gave 0.3559 CO, and 0.0632 H20. C= 54.99 ; H= 3.95.C,,H,,O,N, requires C: = 55.0 ; H = 3.8 per cent.Ethyl I-Nycls.indone-2-cni.60xylccte, C,H,<Co->CH* C02Et.( 3 3 2Ethyl 1-iminohydrindone-2-carboxylate is only very slightly changedwhen its solution in concentrated hydrochloric acid is poured intoboiling water, conditions which completely hydrolpse the correspondingnitrile to the ketone (see p. 2277). The hydrolysis can, however, becompletely effected in the following manner : Ten grams of the imino-compound are dissolved in 50 C.C. of alcohol, and rather more than thecalculated quantity of concentrated hydrochloric acid is added. Thesolution is then boiled for three minutes, during which time a largequantity of ammonium chloride separates.It is then cooled andmixed with a large volume of water, when a heavy oil is deposited,which is extracted by ether. The ethereal solution, when freed fromimpurities by washing first with water and then with sodium carbonatesolution, leaves, on evaporation, an oil which distils at 185'/20 mm. asa viscid, colourless liquid. The distillation can only be accomplishedwith emall quantities, otherwise rapid decomposition ensues :0.2169 gave 0.5593 CO, and 0.1168 H,O.EthyE l-hydrindone-2-carboxyZai% gives in alcoholic solution an intenseblue coloration with ferric chloride. It is soluble in dilute aqueouspotassium hydroxide and in cold alkaline carbonate solutions, but itcannot be extracted from its solution in ether by shaking with thesereagents.When excess of aqueous potassium hydroxide is added to asolution of the ketone in the dilute alkali, a sparingly soluble potassiumsalt separates. When freshly precipitated, this salt is readily solublein both ethyl and methyl alcohol, but if the solution in either of thesesolvents is kept, colourless, silky needles separate, which are verysparingly soluble in hot alcohol :0,3192 gave 0.1127 K2S0,. K = 15-83.C,,H,,O,K requires K = 16.1 per cent.It is probable that the salt whenfirst precipitated contains water ofcrystallisation, although no satisfactory analysis could be made of thehydrated product.The phenylhydraxone, C18H1802N2, is formed when either the ketoneor the imino-compound, dissolved in glacial acetic acid, is mixed with asolution of phenylhydrazine acetate and boiled.It separates as an oilon dilution, and solidifies on scratching. When recrystallised fromalcohol, it forms pale yellow needles, which melt at 1 0 1 * 5 O :C = 70.33; H=5*98.C,,H,,O, requires C = 70.6 ; H = 5.9 per cent2274 MITCHELL AND THORPE: THE FORMATION AND0.1861 gave 0.5001 CO, and 0.1036 H,O.Cl8HI8O2N2 requires C = 73.5 ; H = 6.1 per cent.The sernicarbazone, C13H1503N3, is precipitated when a solution ofthe ketone in dilute alcohol is mixed with an aqueous solution ofsemicarbazide acetate. It crystallises from dilute acetic acid in slenderneedles, which melt and char at 200° :C= 73-30 ; H= 6.13.0,1445 gave 0.3161 CO, and 0.0756 H,O.l-€€~drindone-2-carbuniZide, c 6 H 4 < ~ ~ ~ c H * C O * N H l ? h , is formedwhen the ethyl salt is boiled with an equal volume of aniline for fiveminutes and the solution is poured into dilute hydrochloric acid.Itcrystallises from alcohol in colourless, lustrous plates, which meltat 177" :C=59*66 ; H=5*81.C13Ml,03N8 requires C = 69.8 ; H = 5.8 per cent.0.1560 gave 0.4369 CO, and 0,0754 H20. C = 76.38 ; H = 5.37.C16H,,02N requires C = 76.5 ; H = 5.2 per cent.a-Hydrindone.This ketone is most conveniently prepared by passing a current ofsteam through ethyl 1-hydrindone-2-carboxylate or the imino-compoundsuspended in boiling 10 per cent. sulphuric acid. The ketone passesover with the steam, and solidifies in the receiver. It melted at 41°,and was characterised by conversion into the semicarbazone melting at237O.The formation of anhydro-bishydrindene was not observed, theyield of the ketone being practically quantitative.Ethyl 3-Meth yl- 1 -hydrindone-2 -carboxyZate, ~C6H4<~~~>CH*CO2Et.This compound may be prepared in the following wa.y: Eightgrams of ethyl 1-hydrindone-2-carboxylate are added to a solutioncontaining 1 gram of sodium dissolved in 20 C.C. of alcohol, when acopious precipitation of the sodium salt takes place. Excess of methyliodide is then added, and the mixture is heated on the water-bathuntil the sodium compound, which is practically insoluble in hotalcohol, has all passed into solution. The product is then freed fromalcohol by evaporation on the water-bath, diluted with water, and theoil which is then precipitated is extracted by ether.The etherealextract, after being washed with sodium carbonate solution, is driedand evaporated, when it leaves an oil which distils at 181°/20mm. as amoderately viscid, colourless liquid :0.1848 gave 0.4817 GO, and 0*1848 H20. C= 71.09 ; H = 6.70.C,,H,,O, requires C = 71.6 ; H = 6.4 per centREACTIONS OF IMINO-COMPOUNDS. PART XIV. 2275Ethyl 3-mthyZ- 1 - h ~ d ~ ~ i r t d o n e - 2 - c a r ~ o x y ~ ~ is insoluble in aqueouspotassium hydroxide, and gives no coloration in alcoholic solutionwith ferric chloride.The semicarbazone, C14H1703N3, is precipitated when a solution ofthe ketone in dilute alcohol is mixed with an aqueous solution ofsemicnrbazide acetate.It separates from dilute methyl alcohol inclusters of small needles, which melt at 150' :0.1692 gave 0.3794 CO, and 0.0956 H,O. C = 61-14 ; H = 6.28.C,,H,~0,N3 requires C = 61-1 ; H = 6.2 per cent.3-Methyl-1 -hydkdone, C,H4<co->CH,. CHMeThis substance is formed when ethyl 3-methyl-1-hydrindone-2-mrboxylate, suspended in 20 per cent. sulphuric acid, is treated witha current of steam. The ketone, as it is formed, passes over with thesteam, and can be obtained as a colourless liquid, boiling at 250'1756 mm., on extracting the distillate with ether :0,1693 gave 0.5118 CO, and 0*1080 'H,O.CloH,,O requires C = 82.2 ; H = 6.8 per cent.The phenylhydrazone, C,,H,,N,, separates as an oil, which solidifieson scratching, when a hot solution of the ketone in dilute acetic acidis mixed with a hot solution of phenylhydrazine acetate.Itcrystallises from dilute alcohol in glistening yellow plates, meltingat 95':C = 82.46 ; H = 7-01,0.1684 gave 05025 CO, and 0.1035 .H,O.The semicarbazone, C11H1,0N3, prepared in the usual way,0.1049 gave 0.2493 CO, and 0.0614 H,O.C = 81-27 ; H = 6.69.C,,H,,N, requires C = 81.4 ; H = 6.8 per cent.crystallises from dilute alcohol in slender needles, melting at 190' :C = 64-81 ; H = 6.50.C,,H,,ON, requires C = 65.0 ; H = 6.4 per cent.EthyZ a-o-Dicpano-P-pheny Zpropionate, CN*C,H,*CH,*CH( CN)*CO,Et.-The condensation of o-cyaaobenzyl chloride with the sodiumcompound of ethyl cyanoacetate, if carried out in the usual manner,yields very little of the above product or of ethyl 1-imino-2-cyano-hydrindene, the chief compound formed being ethyl a-oo-tricyano-Pp-diphenylisobutyrate, which is produced to the extent of about 80 percent.of the theoretical quantity. If, however, the condensation iseffected in the following manner, a good yield of the normal productcan be obtained : Two grams of sodium are dissolved in 50 C.C. ofalcohol, and 10.3 grams of ethyl cyanoacetate are added, the solutionbeing kept warm in order to prevent the sodium compound fro2276 MITCHELL AND THORPE: THE FORMATION ANDcaking. The hot sodium compound is then added to a hot solution of13-5 grams of o-cyanobenzyl chloride in 20 C.C. of alcohol, and tbemixture kept hot until the reaction is finished.The bulk of thealcohol is then distilled off, and the residue diluted with water, whenan oil separates which becomes partly solid. On extracting withether, the solid, which was found to be ethyl a-oo-tricyano-PP’-dipheoyl-isobutyrate (see p. ZZSO), remains undissolved, and can be separatedfrom the ethereal solution of the oil by filtration. The residueleft on evaporating the dried ethereal extract is then distilled underdiminished pressure. It is a viscid, colourless liquid, which boils a t220°/20 mm. :0.1921 gave 0,4844 CO, and 0-0934 H,O.C,,B,,O,N, requires C = 68.9 ; H = 5.3 per cent,EtlLyZ a-o-dic?lano-P-pAen?l~p~opionate does not dissolve in coldconcentrated hydrochloric acid. Its structure is shown by theformation of o-carboxy-P-phenylpropionic acid from it on completehydrolysis with dilute snlphuric acid.C = 68-77 ; H --= 5.40.I -1mino-2-c yanohydrindem, C,H,<~&~-~>CH* CN.This substance may be prepared either by the action of sodiumet hoxide on ethyl a-o-dicyano-p-phenylpropionate, or by the directcondensation of o-cyanobenzyl chloride with the sodium compound ofethyl cyanoacetate in the presence of excess of sodium ethoxide.(1) Fyom Ethyl a-o-Bicyano-P-pheny1propionate.-In this preparation10 grams of the dicarboxylic ester are dissolved in 25 C.C.of alcohol,and mixed with 1 C.C. of a solution of sodium ethoxide containing1 gram of sodium dissolved in 10 C.C. of alcohol. The solution, whichbecomes brown in colour, is then warmed on the water-bath for fiveminutes, when it is cooled and diluted with an eqaal volume of water.Crystals separate on scratching, which, when recrystallised frombenzene, form large prisms, melting at 137’.The mother liquor from the condensation, when extracted by ether,yields a residue on evaporating the solvent, which when carefullyfractionated furnishes a considerable amount of ethyl carbonate,boiling at 126’.(Found, C = 50.58 ; H = 8.61. Calc., C= 50.8 ;H =I 8.5 per cent.)(2) Prom Ethyl Sodiocyanoacetate and o-QyanobenxyZ Chlo&de,-This method of preparation always yields the imino-nitrile mixed withsome ethyl a-oo-tricyano-fl~-diphenylisobutyrate, from which it cannotbe readily separated. If the ketone is required, it can be quicklyisolated pure by this means, because it is only necessary to treat themixture with hot dilute hydrochloric acid, extract with ether, andshake out the ketone by means of sodium carbonate solution, in ordeREACTIONS OF JMINO-COMPOUNDS.PART XIV. 2277to obtain the pure product on acidifying the alkaline extract. Owingto the ease with which the irnino-compound is hydrolysed to theketone by hydrochloric acid, it is not advisable to separate themixture by the aid of this reagent. Ultimately the following processwas found to give satisfactory results.The condensation was effected in the same manner as described forethyl a-o-dicyano-p-phenylpropionate (see p. 2275), and when thereaction was finished a slight excess of sodium ethoxide was addedand the heating continued for fifteen minutes.Water was then added,and the solid which separated was collected. It was then rubbed withcold methyl alcohol, filtered from the undissolved di-derivative, andprecipitated from the methyl-alcoholic solution by the addition ofwater.After this process had been repeated twice, the dried product wasrecrystallised from benzene, when i t was obtained in large prisms,melting at 137" :0.1898 gave 0.5346 CO, and 0.0907 H,O. C= 76.83 ; H= 5.31.C,,H,N, requires C = 76.9 ; H = 5.1 per cent.1-lrnino-2-cyanohydrindene is at once soluble in cold concentratedhydrochloric acid. When treated in hot acetic acid solution witha solution of phenylhydrazine acetate, it yields the same hydrazone as2-cyano-1-hydrindone (see p.2278).This compound is readily prepared from 1 -imino-2-cyanohydrindeneby hydrolysis with dilute hydrochloric acid, for which purpose thefollowing conditions were found to give the best results. Ten gramsof the imino-compound were dissolved in concentrated hydrochloricacid, and the clear solution poured into twice its volume of boilingwater, the solution being cooled as quickly as possible after theaddition of the acid. An oil separated, which was extracted by ether,the ethereal extract being shaken with dilute sodium carbonatesolution. The alkaline extract was then acidified, when an oil wasprecipitated which solidified on scratching. When collected andrecrystallised from dilute aloohol, it formed small, colourless needles,melting at 73O :0.1738 gave 0.4845 GO, and 010712 H,O.2-Cyano-1-hydrindone is readily soluble in dilute alkaline carbonatesolutions.When dissolved in dilute aqueous potassium hydroxide, thepotatwium salt separates on the addition of excess of the alkali. Theketone gives a green coloration in alcoholic solution with ferric chloride.C = 76.03 ; H = 4.55.C,,H,ON requires C = 76.4 ; H = 4.5 per cent2278 MITCHELL AND THORPE: THE FORMATION ANDThe phenythydrazone, C,,H,,Ns, is precipitated when a solutionof the ketone in dilute acetic acid is warmed with a solution of phenyl-hydrazine acetate. It separates from alcohol in pale yellow needles,melting at 160° :0.1797 gave 0*5110 CO, and 0.0851 H,O.The 0-bsnxoyl derivative, C17H1102N, can be prepared in small yieldIt crystallises from alcohol inC = 78.16 ; H = 4-10,C = 7’7.55 ; H = 5.26.Cl6H1,N, requires C -- 77.7 ; H = 5.3 per cent.by the Schotten-Baumann method.long, colourless needles, melting a t 101.5O :0,1355 gave 0.3884 CO, and 0.500 H,O.C1’1H1102N requires C =: 78.1 ; H = 4.2 per cent.When 2-cyano-1-hydrindone is boiled with dilute sulphuric acid(10 per cent.) for five hours and the product is distilled in a current ofsteam, a-hydrindone is formed, and passes over with the steam.2-C yano- 3-methox yindene, C,H,<gg2EXX?N.The above methoxy-derivative is the sole product of the methylationof 2-cyano-1-hydrindone whether the alkylation is carried out by meansof sodium methoxide and methyl iodide or whether the pure potassiumsalt is used for the purpose.The preparation can be convenientlyeffected as follows: The potassium salt prepared by the additionof excess of potassium hydroxide to a solution of the ketone in diluteslkali is purified by rubbing with cold ethyl alcohol, and is thensuspended in methyl alcohol and treated with excess of methyl iodide.The mixture is heated on the water-bath until all the salt has passedinto solution, when i t is evaporated on the water-bath and treated withwater. The oil which is then precipitated is extracted with ether, andthe ethereal extract dried and evaporated. The residue distils at185O/20 mm. as a clear, colourless oil, which is quite insoluble in colda1 kali :0.2013 gave 0.5691 CO, and 0.0978 H,O.CllH,ON requires C = 77.2 ; H = 5.3 per cent.The methoxy-structure of the compound is clearly shown by itsbehaviour on hydrolysis, for when it is treated with warm aqueouspotassium hydroxide it slowly dissolves, and when the solution isacidified a crystalline substance melting at 73” is deposited.Thiscompound was shown by direct comparison to be identical with2-cyano- 1 -hydrindone.C = 77.11 ; H = 5.4.Ethyl o-Cyano-a-benxylacetoacetate, CN*C,H,*CH,*CHAc*CO,Et.The conditions employed in preparing this substance were asfollows : 21.7 Grams of ethyl acetoacetate were added to an alcoholiREACTIONS OF IMINO-COMPOUNDS. PART XIV. 2279solution containing 3.5 grams of sodium, and the mixture slowly addedwhile hot t o a hot solution of 25 grams of o-cyanobenzyl chloride in25 C.C.of alcohol. The reaction was vigorous, and when all the sodiumcompound had been added, the product was found t o give a neutralreaction. The greater portion of the alcohol was then distilled off andthe residue mixed with water, when an oil separated, which wasextracted by ether, The product obtained, after evaporating the driedethereal solution, boiled a t 210°/20 mm., forming a viscid, colourlessliquid :0.1972 gave 0-4947 CO, and 0*1100 H20,C,,H,,O,N requires C = 68.6 ; H = 6.1 per cent.Ethyl o-cyano-a-benxylacetoacetate is not affected by cold concentratedhydrochloric acid, and on complete hydrolysis with dilute sulphuricacid yields o-carboxy-P-phenylpropionic acid.C = 68.47 ; H = 6.19.The Transformation of Ethyl o-Cyano-a-benzylacetoacetate into Ethyl1 -Iminohydp.indene-2-carboxy?ate.This conversion was effected by the action of sodium ethoxide in thefollowing manner : Ten grams of the ester were dissolved in alcohol,treated with 1 C.C.of a 10 per cent. solution of sodium ethoxidein alcohol, and then warmed on the water-bath for fifteen minutes.At the end of this time the solution, which had a strong odour ofethyl acetate, was mixed with water, and the solid which thenseparated was filtered. When recrystallised from dilute alcoholit was melted at 98O, and was proved, by direct comparison, to beidentical with ethyl 1-iminohydrindene-2-carboxylate.The aqueous mother liquor from the condensation was saturated withammonium sulphate and extracted with ether, the ethereal extractbeing washed with calcium chloride solution to remove alcohol, dried,and fractionated.The fraction boiling at 78O was collected, and provedfrom its odour and analysis to be ethyl acetate. (Found, C = 54.49 ;H=9.21.When ethyl 1-iminohydrindene-2-carboxylate is required in largequantities, the best method for its preparation is the direct condensa-tion of ethyl sodioacetoacetate and o-cyanobenxyl chloride in thepresence of a slight excess of sodium ethoxide, because in thiscondensation the formation of the di-derivative does not take place toany appreciable extent. The product of the condensation, whichsolidifies on pouring into water, is separated in a pure condition bydissolving in concentrated hydrochloric acid, filtering, and extractingthe filtrate after dilution with water with ether, The yield of ethyl1-iminohydrindene-2-carboxylate under these conditions is 80 per cent.of the theoretical.Calc., C e 5 4 .7 ; €€=9*1 per cent.2280 MITCHELL AND THORPE: THE FORMATION AND?'he Di-o-cyanobenxy? DeYivatiz;es Formed in the ForegoingCondernscctions.Ethyl di-o-cyanobenzylmalonate, (CN'C,H,*CH,),C(CO,Et),, ande t hy 1 di-o-cy a nobenz y lace toace t ate, (CN-C,H,* CH,),CAc* CO,E t, ob-tained as by-products i n the condensations of o-cganobenzyl chloridewith ethyl sodiomalonate and ethyl sodioacetoacetate respectively,have been prepared and described by Gabriel and Hausmann (Zoc. cit.),but they were not further investigated. The following is a descriptionof the products which these compounds yield on hydrolysis, as well asof those derived from ethyl a-oo-tricyano-PP'-diphenylisobutyrate,which has not been prepared before.Ethyl u-oo-Tricyano-pp1-dip~7LenyZisobutyrate,(CN*C,H,*CH,),C( CN)*CO,Et.This substance is obtained as a by-product in the condensationof ethyl sodiocyanoacetate with o-cyanobenzyl chloride, and remuinsundissolved after the imino-nitrile has been separated by the methoddescribed on page 2276.It separates from alcohol in small,colourless needles, melting a t 123' :0.2121 gave 0.5695 CO, and 0.1002 H,O.The ester is sparingly soluble in ether.C = 73-27 ; H = 5.25.C2,Hl7O2N3 requires C = 13.5 ; H = 5.0 per cent.a-oo-Tricyano-pP'-diphenylisobutyric Acid,(CN*C,H,*CH,),C(CN)*CO,H.When ethyl a-oo-tricyano-@'-diphenylisobutyrate is warmed withaqueous potassium hydroxide, it passes into solution, and if, when allhas dissolved, the solution is cooled, an oily potassium salt separates,which dissolves on the addition of more water.On acidification, theclear solution deposits an oil which solidifies on stirring, and the solidcan then be recrystallised from hot alcohol, from which solvent itseparates as a microcrystalline powder melting at 175' with vigorousevolution of gas :0.1508 gave 0.3988 CO, and 0.0569 H,O. C = 72.12 ; H = 4.18.C,,H,,O,N, requires C = 73.4 ; H = 4.1 per cent.oo-Dicyano-PP'-d~phenyZiso6utyronitr~Ze, (CN*C6H,*CH2),CH*CN.This substance is formed when the above carboxylic a J d is heatedat 170' in a bath of sulphuric acid until all carbon dioxide has beenevolved. The dark-coloured residue solidifies on being rubbed witREACTIONS OF IMINO-COMPOUNDS. PART XIV.2281ether, and at the same time becomes colourless. It may be furtherpurified by recrystallisation from methyl alcohol, from which solvent itseparates in large, flattened needles, melting at 132-133" :N = 25.3. 0.1733 gave 23.2 C.C. N2 at 1 8 O and 733 mm.The trinitrile is readily soluble in hot methyl or ethyl alcohol andCl8Rl3N3 requires N = 15.5 per cent.It is sparingly soluble in ether or light petroleum. in hot benzene.oo- D icarboxy-PP-diphenyliso but yric Acid,(CO,H*C,H,* CH,),CH*CO,H.This acid is formed by the ultimate hydrolysis of the di-o-cyanobenzylderivatives described above.From Ethyl a-oo-T&yano-~~'-diphenyZisobuty~*ate.-!I!he ester isdissolved in concentrated sulphuric acid, and water is added until thesolution just remains clear, when i t is boiled on the sand-bath until anoil begins to separate, More water is then added until the solutionis clear, when it is again heated until oil begins to separate.Thisprocess is continued for two hours, when the solution, which on coolingdeposits large quantitias of oil, is extracted by ether. When theethereal extract is shaken with aqueous sodium carbonate and thealkaline extract acidified, a gummy acid is precipitated, which readilysolidifies when rubbed with methyl alcohol, and crystallises fromdilute alcohol in small needles, melting at 210'.Rrom Ethyl Di-o-cyanobenxyZmaZo~ate.-When this ester is boiled withan alcoholic solution containing one and a-half times the quantity ofpotassium hydroxide calculated for complete hydrolysis, and the heat-ing is continued until all ammonia has apparently been given off, thesolution on evaporating and acidifying yields a resinous acid. Whenthis resin is extracted by ether, a large quantity of crystalline solidremains undissolved by the ether, and can be isolated by filtration.It can be recrystallised from much hot water, and is then obtained insmall needles, melting at 2 2 7 O . The analysis and properties of thissubstance showed it to be the acid diamide of the formula(NH2*CO*C6H4-CH2),CH*C0,H :0.1820 gave 0.4430 CO, and 0.0942 H,O.C,,H,,O,N, requires C = 66.3 ; H = 5.5 per cent.The following titration was also made : 0.2600 required 8.1 C.C. ofN/lO-NaOH for neutralisation, whereas this amount of a monobasicacid, C,813[,804N2, requires 8.00 C.C.The acid diamide when boiled for some time with excess of aqueouspotassium hydroxide evolves ammonia, and the solution on rlcidifyingyields a gummy acid, which soldifies on rubbing with alcohol, Whenrecrystallised from dilute alcohol it forms small needles, melting atVOL. XCVII. 7 KC=66*38; H=5*762282 THORPE AND SIMMONDS: LEAD SILICATES IH210°, which are identical with those of the acid prepared from ethyla-oo-tricyano-P~-diyhenylisobutyrate :0.2735 gave 0,4190 CO, and 0,0777 H,O.C18Hls06 requires C = 65.9 ; H = 4.9 per cent.The ethereal solution after the separation of the above acid diamideyields an oily residue on evaporation, which solidifies when rubbedwith alcohol, It crystallises from dilute alcohol in yellow prisms,which melt a t 142O, and yields a semicarbazone melting a t 256'. Wehave not as yet succeeded i n assigning any satisfactory formulze tothese substances.C = 65.86 ; H = 4.97.Some of the expense entailed by this research has been met bygrants from the Government Grant Committee of the Royal Society,for which we desire to express our indebtedness.THE SORBY RESEARCH LABORATORY,THE UNIVERSITY, SHEFFIELD

ISSN:0368-1645    

DOI:10.1039/CT9109702261

出版商:RSC    

年代:1910

数据来源: RSC

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2282 THORPE AND SIMMONDS: LEAD SILICATES IXCCXXX1X.-Lead Silicates in Relation to PotteryManufacture. Part 11.By SIR EDWARD ‘FHORPE AND CHABLES SIMMONDS.SONE years ago, in connexion with the question of lead poisoning inthe pottery industry, we made a study of various complex lead silicatesemployed in the production of ceramic glazes (“Lead Silicates inRelation to Pottery Manufacture,” Trans., 1901, 79, 792). I nparticular, we showed that the quantity of lead which could bedissolved from a silicate by dilute acids depended primarily on the typeof silicate. Monosilicates are easily attackable. Polysilicates anddisilicates are but slightly so, and this is the case whether theycontain little or much lead. We further showed that in the caseof the polysilicates and disilicates, as ordinarily prepared, there isfrequently a small quantity of an easily soluble lead compound mixedwith the bulk; this could be extracted with dilute acid, leaving theresidue practically unattackable under the conditions of the experi-ment.A fairly complete summary of present knowledge of lend silicatesand glazes in respect of the foregoing properties has recently beenpublished by Beck, Ldwe, and Stegmuller,* who have studied the action* “Zur Kenntniss der bleihaltigen Glasuren und deren Bleiabgabe an saureFliissigkeiten ” (Arbeit.K. Gesundhcitsamte, 1910, 33, No. 2)RELATION TO POTTERY MANUFACTURE. PART 11. 2283of acids both on the powdered silicate and on the fused glaze as itexists on the finished pottery ware.With certain modifications, theyhave repeated our experiments; but whereas our studies, made onsilicates in actual commercial use, were of necessity chiefly concernedwith the complex silicates, containing not only lead but other bases,Beck, Lome, and Stegmiilier have adopted what in some respects is thebetter plan of studying first the simple lead silicates.The results they obtain lead, however, to the same conclusions as ourown. Thus the proportion of lead oxide dissolved from three simplesilicates was found to be as follows :PbO dissolved by 1 per cent. HNO,.A/- >PbO present Percentage ofSilicate grams Amount total PbOPhO,SiO, ............ 1’529 1.525 99-7Pb0,2Si02.. .......... 1’232 0-106 8.6Pb0,3Si02.. .......... 1 *038 0.019 1 -9That is, practically all the lead is dissolved from the monosilicate,but a relatively small quantity only from the disilicate and trisilicate.On a further treatment of the di- and tri-silicate residues, very littleadditional lead was extracted (0.5 and 0.6 per cant.respectively).This confirms what has already been stated (Zoc. cit., p. 802).An explanation of the fact that a single treatment with acid extractssubstantially the whole of the “soluble ” lead from the di- and the tri-silicates is suggested by the German authors. A t the temperature offusion a certain amount of dissociation may occur ; thus the disilicatePbSi,05 may partly dissociate into PbO + 2SiO,, or into PbSiO, + SiO,,and a portion of these components may remain dissociated when thesilicate cools.Since both lead oxide and monosilicate are readily solublein dilute acids,they would, if the silicate were sufficiently finely powdered,be all extracted on a single treatment with acid, whilst even from arelatively coarse powder the bulk of this “soluble” lead would beremoved.In the paper quoted we give a table (pp. 796-797) illustrating thefact that whether a lead silicate yields much soluble lead or notdepends mainly on the value of the ratio : number of acidic molecules/number of basic molecules. Beck, Lowe, and Stegmuller remark t h a twhilst this appears capable of rendering good service for rapid sorting-out purposes, it gives no special insight into the effect of a particularconstituent in individual cases.They note that the effects of boricoxide and alumina are contrary to what would be expected from thetable, and suggest that the possibility of the formation of complexborosilicates and aluminosilicates may have been overlooked. Also theyremark that the possibility of alumina acting as an acidic oxide mustnot be excluded (Zoc. cit., p. 226).The authors in question, however, have quoted the table from a,7 ~ 2284 THORPE AND SIMMONDS: LEAD SILICATES INParliamentary Paper in which it was reproduced (‘‘ Lead Compoundsin Pottery,” 1901, Cd. 679, p. 26-27). On reference to the originalpaper already referred to ( h e . cit., p. 799), it will be seen that thepoints they mention had not been lost sight of. We note there that“ subsidiary factors may exist in the possible different states of com-bination in which aIumina and boric oxide may occur in the silicate ” ;and we also say ‘‘ it is conceivable that in some cases the alumina mayact as anacid constituent.In such cases, the amount of lead dissolvedwould presumably be less than indicated by the value of the ratio.”Further on we briefly discussed the influence of boric oxide.These views, put forward tentatively, were arrived at from acomparison of the results yielded by various complex silicates of verydiveroe composition; but it was recognised that the best way ofstudying the matter was to ascertain the effect of each oxide singlyrather than to deduce it from such comparisons.A number of silicates were therefore prepared by fusion of theingredients in the proportions required for certain polysili2ates anddisilicates of definite formula. These silicates, in a finely-powderedcondition, were then shaken continuously for an hour with 1000times their weight of dilute hydrochloric acid (0.25 per cent.), and thequantity of lead dissolved was determined by a colorimetric methoddepending on the comparison of the depth of tint with that given byknown quantities of freshly produced lead sulphide.The results may be thus stated :(I.) IfiJuence of Alumina.Polysilicates&SiO,........... 28’8 35.1PbO ............ 71.2 60.9A1,0, ......... - 4.0100.0 100.0(1) (2)- -- -PbO dissolved 25 5Disilicates&(3) (4)35.1 41 *964’9 54‘53%100-0 100*0-- -- -5 5 per cent.No.1 is the simple lead polysilicate 2Pb0,3Si02( = 10Pb0,15Si02),and No. 2 corresponds with the complex polysilicate7Pb0,A120,,1 5Si0, ;thus the substitution in No. 2 of one molecule of A1203 for threemolecules of PbO has had a very marked effect in decreasing thesolubility of the lead.No. 3 is the simple disilicate Pb0,2Si02( = 10Pb0,20Si02), andNo. 4 is the complex disilicate 7PbO,A1,0,,2OSi0,. Here thesubstitution of Al,03 for 3Pb0 has not affected the proportion ofsoluble lead, or at least, not sufficiently to be evident under thRELATION TO POTTERY MANUFACTURE. PART 11. 2285conditions of the experiment. A similar conclusion appears tohave been arrived a t recently by H. Eisenlohr (Sprechsnal, 1910,43, 389).(11.) Iwfluence of Sodium Oxide.Polysilicate Disilicate( 5 ) (6)5iOZ .....................31 *O 37.9Na,O ..................... 3 -1 3’3PbO ..................... 65.9 58 -8- -100.0 100*0 - -YbO dissolved . , . . , , .. , 44 13 per cent.No. 5 is the polysilicate 2Na20,12Pb0,21Si0, ; it is to be comparedwith No. 1 (= 14Pb0,21Si02).No. 6 is the disilicate Na20,5Pb0,12SiO2 ; its comparison sample isNo. 3 (=6Pb0,L2Si02)’; thus in both cases the substitution ofone molecule of Na,O for one of PbO has materially increased theproportion of soluble lead.(111.) Influence of AZunaina and Xodiunz Oxide Yogether.Polysilicate(7)SiO., .................... 83’8N%O ..................... 1.5PbO ................... 62 *3h1,0,. ...................2 -4-100’084-PbO dissolved . , . , , .Disilicate40‘456 ‘22 -11.3100’0(8)--5 per cent,No. 7 is the polyailicate Na,O,Al2O,,12Pb0,24Si0,. It is to becompared with No. 1 and No. 2, also with No. 5. Relatively toNo. 1, a considerable lowering of the proportion of soluble leadhas been effected, and this, in accordance with (I) and (11), is tobe attributed to the alumina. As compared with No. 2, a largerquantit,y of soluble lead is shown, in agreement with the factthat No. 7 contains a smaller percentage of alumina than No. 2.The proportion ofsoluble lead agrees with that in the simple disilicate No. 3.No. 8 is the disilicate Na,0,A120,,1 2Pb0,32Si02.(IV.) Influence of Bm-on Trioxide.No borosilicates of defioite molecular formulae were made, butthe following results were obtained with modifications of the simpledisilicate 2286 LEAD SILICATES IN RELATION TO POTTERY MANUFACTURE.Modifications30Did icatc - (9) (3150) (1)B,O, -SiO, ........................35 '1PbO 64.9 65 60 ....................... 5 5100.0 100 100........................- - -- - -PbO dissolved ............ 5 53 46 per cent.Thus the substitution oE 5 per cent. of boron trioxide for the samequantity of either silica or lead oxide in the simple disilicate enormouslyincreases the quantity of soluble lead. This effect, however, is notproduced with the complex disilicates, or a t least, not with those of aparticular type. We had already noted (Zoc. cit., p. '799) t h a t from4 to 6 per cent.of boron trioxide was present in certain borosilicateswhich yielded mere traces of lead to the action of solvents. Butin these cases the proportion of silica was higher, and that of the leadoxide much lower, than in the two experiments above described, andnotable quantities of lime and alumina were also present. Which ofthese factors determines the behaviour of the boron trioxide is atpresent obscure. It was precisely the influence of the variousconstituents that we had hoped to ascertain if the work had beencompleted.The results obtained point clearly to the following conclusions :(1) Alumina has a marked effect in promoting the stability of thepolysilicates towards acids. Possibly this is due to its function in thesilicate being that of an acidic oxide.I n the disilicates this effect isless apparent, since these are already tolerably stable.(2) Sodium oxide appears to increase the solubility of the lead,(3) Boron trioxide in some cases renders the silicates much moreeasily attackable, but in others has no such effect.Some experiments described by Beck, Lowe, and Stegmuller lead, inthe main, t o similar conclusions (Zoc. cit., p. 214). With the simplelead silicates they mixed 2+ or 5 per cent. of one or other of thefollowing compounds : Al,O,, B203, CaO, Na,B,07. The mixtures werefused, and the proportion o€ soluble lead was determined in the resultingcomplex silicates. Since by this procedure the acidity of the originalsilicates is modified, the results are not closely comparable withthose that we adduce. Thus the addition of 5 per cent. of lime to thedisilicate raised the percentage of soluble lead from 5.3 to 20.0 ; butthis experiment is not analogous to those we show in (11) with sodiumoxide, because the new compound is notably more basic than theoriginal, and would therefore in any case be expected to yield moresoluble lead. Nevertheless, the general results obtained point in thespecially in the polysilicatesABSORPTION SPECTRA OF SOME SULPHUR COMPOUNDS. 2281same direction as our own. Thus the effect of an addition of5 per cent. of alumina could be traced in the decrease, by about 2 percent., of the soluble lead in the disilicate (no experiments on the poly-silicate are shown), and whilst 5 per cent. of borax raised thesolubility figure of the disilicate from 5.3 to 32.0, the effect onthe trisilicate was very slight, namely, an increase of only 1 per cent.Results of the same order were obtained with 5 per cent. of borontrioxide

ISSN:0368-1645    

DOI:10.1039/CT9109702282

出版商:RSC    

年代:1910

数据来源: RSC

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ABSORPTION SPECTRA OF SOME SULPHUR COMPOUNDS. 2287CCXL-The Colouy* aid Absoqhoub Spectra qf SomeSulphur Compounds.By JOHN EDWARD PURVIS, HUMPHREY OWEN JONES, andHUBERT SANDERSON TASKER.IN a previous paper (Jones and Tasker, Trans., 1909, 95, 1904) thepreparation and properties of some alkyl dithio-oxalates weredescribed. These esters were found to exhibit a distinct yellowcolour, whilst oxalates and oxalyl chloride are colourless.The dithieoxalates were found to have normal molecular weightsin solution, so that it appears as if their colour had been producedowing to the replacement of oxygen by sulphur.It was therefore decided t o study the absorption spectra of theseand some other sulphur compounds of similar structure in order toascertain, if possible, the cause of the colour of thieoxalates.Thevarious ethyl and phenyl mono-, di- and tri-thiocarbonates wereprepared and examined, as were also the corresponding dithio-oxalates, dithiomalonates, dithiosuccinates, and several other com-pounds containing two atoms of sulphur in the molecule. Theresults are described and discussed in this paper. We are not, atpresent, prepared to suggest a hypothesis to account for the resultsobtained; but those so far recorded for a number of coloured com-pounds of simple structure seem to be of value, and the publicationof them may serve a useful purpose.Each compound was obtained as pure as possible, its absorptionspectrum studied in solution of various concentrations in pure ethylalcohol, and the results are represented by curves in the usual way.A large number of the substances show no band due to selectiveabsorption, and, in these cases, it will be sufficient if the reciprocalsof the wavelengths of the last transmitted lines at a thickness of30 mm., and sometimes also of 2 mm., of solution be recorded; whenthe substance exhibits a band, the position of its head is also noted.The following compounds were examined2288 PURVIS, JONES, AND TASKER: THE COLOUR ANDT hio car6 onat es.Diethyl thiocarbonate, OEt-(TO-SEt, was prepared by the actionof ethyl chlorocarbonate on sodium ethyl mercaptide (Sa.lomon,J .pr. Chem., 1873, [ii], 7 , 255).Diethyl thioncarbomte, OEt-CS-OEt, was prepared as describedby Debus (Annulen, 1850, 75, 136), by the action of heat on ethylxanthate, and was separated from the compound OEt.CS*SEt,which is formed at the same time, by repeated fractional distillation,until the product boiled between 161O and 161'5O.Several analyses established the purity of the substance, whichhad a marked yellow colour.(For example: Found, S=23*9.C,H,,O,S requires S=23*9 per cent.) We were not able to preparethis compound by the action of thiocarbonyl chloride on sodiumor potassium ethoxide.Diphenyl thioncarbonute, OPh-CS*OPh, waa prepared by theaction of thiocarbonyl chloride on aqueous sodium phenoxide(Bergreen, Ber., 1888, 21, 346; Eckenroth and Koch, Ber., 1894,27, 1369).The compound has been described a8 crystallisiag in colourlessplates, but it was found that, after repeated recrystallisation fromalcohol and other solvents, the compound still retained a verydistinct cream colour.The colour was not intense, and smallquantities of the substance might be taken to be colourless, whereasin large quantities the colour is unmistakable.Diethyl dithiocarbonate, SEt*CO*SEt, was prepared by the actionof carbonyl chloride on sodium ethylmercaptide (Salomon, J . p ~ .Chern., 1872, [ii], 6, 443).Diphenyl dithiocmhorutte, p-repared by the action of carbonylchloride on sodium thiophenoxide, crystallises from alcohol in longneedles, melting at 43O, and is quite colourless.Diethyl thionthiocarbonate, OEt-CS-SEt, prepared by the actionof ethyl bromide on potassium xanthate (Salomon, Zoc. cit., p. 445),shows a, distinct yellow colour very similar to that of diethyl thion-carbonate.DiethyZ tm'thiocarb onate, prepared by the action of thiocarbonylchloride on sodium ethylmercaptide, is a deep reddish-orange liquid,boiling at 240°/760 mm.and at 118-119°/10 mm. (Debus,tlnnalen, 1850, 75, 147).Diphenyl trithiocarbortate was prepared by the action of thio-carbonyl chloride on sodium thiophenoxide. It crystallises fromalcohol in short prisms, melting at 43O, and showing a golden-yellow colour lighter than that of the ethyl compound:C,,H,,S requires C = 59.5 ; H = 3-82 per cent.0.1998 gave 0'4335 CO, and 0.0690 q0. C=59*2; H=3*84ABSORPTION SPECTRA OF SOME SULPHUR COMPOUNDS. 2289Diethyl monothio-oxalate, prepared by the action of sodium ethyl-rnercaptide on ethyl chloroglyoxylate (" chloroxalic ether "), asdescribed by Morley and Saint (Trans., 1883, 43, 400), is a liquidboiling at 216O, which shows a very pale yellow colour when examinedin thick layers.The various alkyl dithio-oxalates have already been described(Jones and Tasker, Zoc.cit.).Diethyl dithiornalonate, prepared by the action of malonylchloride on sodium ethylmercaptide, is a colourless liquid, boiling at135O/10 mm. On distilling under atmospheric pressure, this esterappears to undergo decomposition with the formation of derivativesof ethyl mercaptan :0.3421 gave 0.5443 CO, and 0.1894 H,O.C,H,,O,S, requires C = 43-8 ; H = 6.25 per cent.Biphenyl dithiomalonat e, prepared by the action of malonylchloride on phenyl mercaptan or its lead salt, crystallises in long,colourless needles, melting at 94-94'5O :C=43.4; H=6*15.0.2700 gave 0.6151 CO, and 0-1055 H,O.C,,H,,O,S, requires C = 62.5 ; H =4.17 per cent.Diethyl dithiosuccimte, prepared by the action of succinylchloride on sodium ethylmercaptide, is a colourless liquid, boiling at165O/10 mm.The product when first formed was slightlyfluorescent; the fluorescence persisted after distillation, but wasremoved by washing with dilute sodium hydroxide solution :C =46.4 ; H = 6-91.C = 62.1 ; H = 4.34.0.2355 gave 0.4010 CO, and 0.1465 H,O.C8H1,0,S, requires C =46*6 ; H = 6.8 per cent.Diphenyl dithioszcccinat e, prepared by the action of succinylchloride on phenyl mercaptan, crystallises from alcohol in colourlessneedles, melting at 90-90'5O :0.1887 gave 0.4375 CO, and 0.0807 H,O.It may be mentioned that succinyl chloride, which is describedas a liquid, when pure sets to a crystalline solid, melting at 17O.Ethyl ethylthiolacetate, SEt*CH,*CO,Et, prepared from ethylchloroacetate and sodium ethylmercaptide in the cold, is a colourlessoil, boiling a t 187-188O (Claesson, Bull.SOC. chim., 1875, [ii], 23,E thy1 ethyl thiolthioacetate, SEt*CH,*CO*SEt, was prepared bythe action of chloroacetyl chloride on sodium ethylmercaptide ; thereaction was started in a freezing mixture, and completed at 1000.The compound is a colourless liquid, boiling at 101-102°/5 mm.:C,H,,OS, requires S = 39.0 per cent.C = 63.3 ; H = 4-75.C16H140,S, requires C = 63.6 ; H = 4.64 per cent.445).0.2163 gave 0.6095 BaS04. S=38*72290 PURVIS, JONES, AND TASKER: THE COLOUR ANDs-Diethglthiolethae, SEt-CH,*CH,*SEt, prepared by the actionof ethylene dibromida on sodium ethylmercaptide at looo, is acolourless liquid, boiling at 210° (Ewerlof, Ber., 1871, 4, 717;Meyer, Ber., 1886, 19, 3266).Phenyl mercaptan was obtained from Kahlbaum, and thiocarbonylchloride from Schuchardt; both were purified by distillation.Di-phenyl disulphide was prepared and purified by repeated crys-tallisation until quite colourless.We are indebted to Professor Pope for a specimen of pure benzylsulphide.Carbonates.An examination of the absorption curves (Figs. 1 and 2) showsthat well-marked bands are exhibited by diethyl dithio- and trithio-carbonates (MI 1000-solutions), a less pronounced band by diethylthioncarbonate (MI 100-solution) and by diphenyl carbonate anddithiocarbonate ( H / 1000-solutions), and by diphenyl thion- andtrithio-carbonates (M / 10,000-solutions).Table I gives the limits ofgeneral absarption in oscillation frequencies at a thickness of 30 mm.,and, when stated, also at 2 mm.; the position of the head of theabsorption band, when one is present, is also given.TABLE I.Strength ofCO(OEt), (colourless) { 5;:; (2 nmi.)CO(OEt)(SEt) (colonrless) ... { $$: (2 n,m.)CS(OEt), (yellow) { t$;oSubstance. solution..........CO(OPh), 9 2 ......... M/100CO(OPh), ,, ......... 1w/1000CO(OEt)(SEt) ,, ... M/lOOO...............CS(OEt), ,, ..............M/lO,OOOCS(OPh), (cream coloured) ... M/100CS( 0 Ph), ... nq1000CO(SEt), (colonrless) ......... M / l O OCO(SEt), 9 , ......... ll1/10,000CO(SPh), 9 , ......... M/1000CS(OEt)(SEt) (yellow) ......... M/100CS (0 E t)( SEt) , , ......... Jf/lOOOCS(SEt), (orange) ............. Jf/lOOCS(SEt), ,, ............... llf/lO,OOOCS(SPh), (goldei~-yellow). ..... M/100CS (SPh), 2 8 ..,..# ~!/10,000f Jl/lOY Y............... CSCI, (orange-red) -\ M/lOOOHead ofband.3760-328036604058360031603300Limit ofabsorption.4406462035753584343541734254304739803336345335133722340531732801--269530303010350ABSORPTION SPECTRA OF SOME SULPHUR COMPOUNDS. 2291The results given above show that in general the replacement ofan ethyl by a phenyl group causes a shift in the limit of generalabsorption towards the red end of the spectrum.Further, the replacement of oxygen by sulphur in ethyl carbonateand ethyl thioncarbonate causes a very marked increase in theabsorption.The consideration of the cause of the colour and bands exhibitedby these compounds is complicated by the differences which existbetween the ethyl and phenyl esters.Diethyl carbonate showsFIG. 1.Oscillation frcqucncics.31 33 35 37 39 41 43 45merely general absorption but no band, whilst diphenyl carbonateshows a well-defined band (Fig. 2), with its head about 3740,(oscillation frequency) almost identical in position with that ofphenol. This band may therefore be attributed to the presence ofthe phenyl groups, the group O:C<o, having no tendency to producea band.This is the only case in which the modification of thecurve by the substitution of phenyl for ethyl is in the direction ofband formation; usually a band shown by the ethyl ester is partlyand completely obliterated in the phenyl ester, as, for instance, i nthe dithiocarbonate and in the dithio-oxalate, which will be discussed02292 PURVIS, JONES, AND "ASKER: THE COLOUR ANDlater. In the compound CS(OPh),, the band shown by diphenylcarbonate h a been displaced slightly towards the red end of thespectrum, whilst in diphenyl trithiocarbonate the band is so changedthat its form suggests a compromise between the vibration dueto the phenyl groups, and those due to the group S:C<,., whichproduce the band found in diethyl trithiocarbonate.In consequence of these complications introduced by the presenceS*FIG. 2.Oscillai!ion frepmicics.31 33 35 37 39 41 43 45of phenyl groups, the curves of the ethyl esters only can be con-sidered completely comparable with one another.Considering firstthe phemmenon of colour, it is obvious that the mere replacementof one or two oxygen atoms by sulphur does not give rise to colour,since diethyl and diphenyl dithiocarbonates are colourless ; but itis also clear that t>he group :C:S must be regarded as a powerfulchromophore.The following compounds all exhibit colour which may be regardedas caused primarily by the :C:S group : CSCb (orange-red), CS(OEt)AP,SORPTIOX SPECTRA OF SOME SULPHUR COMPOUNDS.2293(yellow), CS(OPh), (cream), thiobenzophenone, CS(Ph), (blue). I nthe case of thiobenzophenone and dimethoxythiobenzophenone, wehave confirmed the results obtained by Gattermann (Ber., 1895, 28,2868) as regards the properties of the compounds and the fact thattheir molecular weights in solution are normal. We have also beenable t o prepare these compounds by the interaction of dry silversulphide and the corresponding chloride. The colour originating inthe :C:S group is very considerably modified by the group to whichit is attached, since in the cases mentioned above it varies fromdeep blue to cream.The difference between the intensity of the colour exhibited bythe compounds CS(OEt), and CS(OPh), is much more marked thanthat between diacetyl and benzil, but the explanation is possiblysimilar to that suggested by Baly and Stewart (Trans., 1906, 89,502) to meet the case of these substances.Until there is more exact knowledge as to the relation betweenthe absorption of light and the structure of organic compounds,i t is not desirable to formulate further hypotheses, but the strikingdifference between the groups :C:S and :C:O may be explained assuggested by Hewitt at the International Congress of AppliedChemistry, 1909, on the following consideration.The attractionbetween carbon and sulphur is less than that between carbon andoxygen, as evidenced by the ease with which the sulphur is replacedby oxygen in the thioketones, thioncarbonates, and thiocarbamides.The mass of the sulphur atom to be held by the smaller force ofattraction is greater, and consequently the period of any vibrationset up would be slower.The bands exhibited by the three compounds CO(SEt),,CS(OEt)(SEt), and CS(SEt), possess a similar shape and persistency,but are shifted successively towards the red end of the spectrum,and become much broader.It is possible that these bands may ariseowing to the formation of linkings between the sulphur atom,which exhibit a greater tendency to become quadrivalent than doesoxygen.0xdat ee.Table I1 gives, for the oxalates and thio-oxalates, the strengthof solution, position of head of band in oscillation frequency, andthe limit of absorption through 30 mm.of solution.Fig. 3 contains the curves for those substances which show bands2294 PURVIS, JONES, AND TASKER: THE COLOUR AND' ~ ' A I ~ J A 11.Strength of Limit ofSubstance. s o h tio 11. Head of hand. ahorption.(CO,Et), (colom.less) . . , . , . , . . M/ 10 __ 3513- (GO&), 9 1 ......... M/lOOO 4423C0,Et 'CO'SEt (almostCO,Et*CO*SEt ,,colourless)(CO'SEt), (yellow).. ..........(CO *SE t), , , ............(CO*S*C,Hv), , , ............(CO *S 'CaH,), , , ............(CO*SPh), ,, ............(CO'SPh), ,, ...........M/100M/lO,OOOMf 10M/lOGOM/10M/lOOOM/lOMf1000M/100iM/lOGORapid extension ofabsorption between3640 and 4000, in-cl icating potential [ band. 1374036403620liapid e s tension ofabsorption between3110 and 3850.3400359327703320246831442484303823803050Table I11 gives similar data, including the limit of absorptionfor a thickness of 2 mm.of solution, for the thiomalonates andother compounds examined, which are all colourless, and none ofwhich show bands.TABLE III.Substance.CH,(CO*SEt), .....................Strengthof solution.J M / l O O O\ M/1000 (2 inni.)M/lOOO .................. CH,(CO*SPh), { M/looo (2 niin.)M/lOOO .................. { M/1000 ( 2 mni.) (CH,*CO *SEt ),Limit ofabsorption.372740633405400538554199M/lOOO 3447 { M/looo (2 mm.) 4005 .................. (CH,*CO'SPh),Nf 1000 4365(CH;SEt), { Jf/1000 (2 mni.) 4603 ........................V/lOOO ..................BEt*CH,-C0,Et { M/1ooo (2 mm.)M/lOOO ............... SEt-CH,*CO*SEt { M/1000 (2 mm.)4354442238304113In all the above cases, the replacement of oxygen by sulphurproduces a very great increase in the absorptive power of thecompound; this is particularly well illustrated by a comparison ofethyl oxalate and monothio-oxalate (table 11) and of the two la&compounds in table 111ABSORPTION SPECTRA OF SOME SULPHUR COMPOUNDS. 2295In the colourless compounds, the replacement of ethyl byphenyl produces a considerable increase in absorption, but this isnot so marked in the coloured compounds, since in the dithio-oxalate the absorptive power of the phenyl compound is inter-mediate between those of the ethyl and propyl compounds.The potential band exhibited by phenyl oxalate is probably dueto the phenyl groups, as in the case of phenyl carbonate, since itsposition is close to that of t'he phenol band.FIG.3.Oscillation frequencies.29 31 33 35 37 89 41 43 45The table and the curves show that both colour and an absorptionband are produced by the structures:R*S*$XO rind Et*S*$XOR-SCO EtO*C:O 'but when R=Ph the band is almost obliterated, it9 in the case ofthe dithiocarbonate. Neither colour nor band is shown by any ofthe other compounds which were examined containing two atomsof sulphur in the molecule. It may therefore be concluded thatthe above structure is associated with the existence of the colourand the band2296 ABSORPTION SPECTRA OF SOME SIIT,PHIJH COM POUNDS.Colour of OcrnZyZ Chloride in Solution.It was observed that, although oxalyl chloride itself and itssolutions in substances like ether, chloroform, and paraffins werequite colourless, yet it forms yellow solutions with phenol, anisole,piperonal, dipentene, and alkyl sulphides.The colour of thesesolutions is similar to, but deeper than, that of the alkyl dithio-oxalates, but the solutions were too unstable to allow of anexamination of their spectra.Oxalyl chloride therefore forms coloured solutions with certainsubstances which also give coloured solutions with tetranitro-methane (Werner, Ber., 1909, 42, 4324). The production of colourfrom oxalyl chloride by admixture with other substances is possiblydue to the formation of additive products with these substances,which, in virtue of the presence of oxygen, sulphur, or ethenoidlinking in the molecule, are capable of forming such additivecompounds.Much further work will be required before definite hypotheses canbe formulated to account for the behaviour of these sulphur com-pounds, and it is hoped that the study may be continued andpossibly extended to some corresponding selenium compounds.The absorption spectra of phenyl mercaptan and benzyl sulphidehave also been examined for comparison with phenol and benzylalcohol.These substances show no band, and the limits of absorp-tion are given in table IV.TABLE IV.Strength of Limit ofSubstance. solution. absorption.M/100 (30 mm.) 3320\ MllOOO (30 mm.) 3460M/100 (30 mm.) 3532........................... C'GHs'SH.....................{ M/lOOO (30 mm.) 3608 (C,H,*UH,),SIt is remarkable that the pronounced band in phenol has beencompletely obliterated by the replacement of oxygen by sulphur,and that tshe three bands in benzyl alcohol (Baly and Collie, Trans.,1905, 87, 1332) have disappeared in benzyl sulphide.The results obtained in the examination of benzyl mercaptan arenot trustworthy on account of the ease with which it is oxidised insolution.The oblitera.tion of bands is possibly to be attributed to thegreater absorptive power of the sulphur compoundsMARSH : DISSOLUTION OF POTASSIUM MERCURI-IODIDE. 2297Cenernl Results.An examination of tjhe absorption spectra of sulphur compoundshas shown that:(1) The replacement of oxygen by sulphur causes a markedincrease in the absorptive power of the compound, and, indeed, oftenresults in the production of colour. An absorption band alsoappears in some cases.(2) Definite absorption bands are shown by sulphur compoundspossessing the following structures, but are not shown by thecorresponding oxygen compounds :0. S* s o -,-yo *s*y:oS:c<@ s:c<"o: o:c<,* s:c<,* *o*c:o *s-c:o(1.) (11.) (111.) (IT. 1 (V.) (VJ. 1Of these, compounds of the type I, 11, IV, and VI are yellow in(3) The group S:C< must be considered a powerful chromophore.(4) I n certain aromatic compounds, such as phenol and benzylalcohol, the replacement of oxygen by sulphur results in obliteratingabsorption bands.(5) It has also been found that, although oxalyl chloride itselfis colourless, it gives yellow solutions with a number of unsaturatedcompounds and compounds containing oxygen or sulphur.colour, and V may be considered as faintly coloured.The expenses of this work were largely defrayed by grants fromthe Government Grant Committee of the Royal Society, and thespectra were examined by means of a spectroscope kindly placed atour disposal by the same body. For both these favours we are gladto make this grateful acknowledgment.UNIVERSITY CHEMICAL LABORATOKP,CAMBRIDGE

ISSN:0368-1645    

DOI:10.1039/CT9109702287

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

MARSH : DISSOLUTION OF POTASSIUM MERCURI-IODIDE. 2297CCXL I .--Pheriomena Observed when Potassium Mercuri-iodide is Dissolved in Ether and Water.By JAMES ERNEST MARSH.POTASSIUM mercuri-iodide, KHgI,,H,O, crystallises well fromalcohol, but is decomposed by water with separation of mercuriciodide. A crystal of the salt changes in colour from yellow to redon being moistened with water. The salt is, however, soluble inwater if heated with a very small quantity; also, when heated inVOL. XCVII. 7 2298 MARSH : PHENOMENA OBSERVED WHEN POTASSIUMa sealed tube, the dry salt melts at 119O, and this liquid may beregarded as a solution of the salt in its water of crystallisation. Thesalt is very sparingly soluble in dry ether, but is somewhat readilydissolved by undried ether, especially by ether which has beenshaken with water and then separated from the latter.The salt,which dissolves in the ether with considerable rise of temperature,is much more soluble in cold ether than in hot. The followingexperiment illustrates this property. A sealed tube was employedcontaining 3.32 grams of powdered potassium iodide and 9.08 gramsof mercuric iodide with 52 C.C. of " wet " ether and 0.6 C.C. of water.A t Oo the contents of the tube are completely dissolved. I f the tubeis now placed in warm water, crystals begin to form, and at 50°the contents of the tube become nearly solid, with the formation oflong, yellow needles of the salt KHgI,,H,O. The crystals re-dissolve in the ether on cooling. Analysis of the salt obtained inthis way gave:Found, H,O = 2-69 ; KI = 25.7.KHgI,,H,O requires H,O = 2-82 ; K I = 26.0 per cent.If potassium iodide and mercuric iodide are mixed with ordinaryundried ether, no apparent solution or other change occurs.Thered and the colourless salts remain unchanged in presence of thesolvent. After many weeks, however, the red colour of the mercuriciodide begins to fade, and its place is taken by the characteristicyellow, crystqlline double salt. This does not dissolve appreciablyin the ether now deprived of its water, but requires '' wet " ether€or its solution.When potassium iodide and mercuric iodide are mixed with etherdried either by sodium or by long keeping over calcium chloride,the double salt which contains water of crystallisation cannot now beformed, and a quite different action occurs.The two salts rapidlyliquefy in the ether, and take up four molecules of ether t o form aheavy, yellow liquid compound. If any excess of ether is taken,i t is left floating on the surface as a separate layer which containsvery little of the salts, and a large excess of ether does not appre-ciably diminish or increase the volume of the liquid compound.If the ether taken is not enough to supply four molecules, thensome of the salts are left undissolved. If mercuric iodide is taken inlarger quantity than one molecule to one of potassium iodide, theexcess is left undissolved.The compound, KHgI3,4E~O.-l.66 Grams of well powdered anddried potassium iodide and 4.54 grams of mercuric iodide weremixed with 4.4 C.C.of dry ether in a sealed tube. On shaking, allrapidly passed into solution. The liquid compound measured 5 c.c.,and the ethereal layer 0.1 c.c., at 7.5O. From these figures thMERCURI-IODIDE IS DISSOLVED IN ETHER AND WATER, 2299formula of the liquid compound and its specific gravity, 1.87, at7 . 5 O are derived. It should be noted that the solubility ofpotassium iodide and of mercuric iodide separately in dry ether isvery slight. The solubility of potassium iodide in ether at theordinary temperature was found to be 0.016 per cent., and ofmercuric iodide 0.3 per cent., and in neither case is there formedany liquid not miscible with ether. The liquid compound of etherand potassium mercuri-iodide is also formed by exposing a mixtureof the two salts in a tube t o the vapour of ether, but in this casesome crystals are also formed in the tube, and the action is veryslow. 0.83 Gram (1 mol.) of potassium iodide and 2.27 grams(1 mol.) of mercuric iodide exposed to the vapour of dry etherincreased in weight by 1.1682 grams (3.1 molecules of ether), whenthe red mercuric iodide justl dissolved? and gave a further increase,in all, 1.5334 grams (4.1 molecules of ether), after keeping for manydays.The compound was also analysed by determining the loss ofweight due to the ether given off on passing a stream of dry air overthe substance. The liquid, when it had lost a certain quantity ofether, began to crystallise, and soon formed a solid mass of crystals.It was then weighed, and the stream of air was continued until allthe ether was expelled.4.2914 Grams of the liquid compound gave3.7086 grams of crystals, and finally 2.6314 grams of potassium andmercuric iodides. These numbers agree with four molecules ofether in the liquid compound, and with 2.5 molecules in thecrystalline compound. As it is difficult to stop when the crystalsare just free from liquid, i t appears more probable that thecrystalline compound is represented by the formula KHgI,,3Et20.When the liquid compound is exposed to moist air, crystals of thehydrated salt KHgI,,H,O a t once form on the sides of the tube.The addition of a small quantity of water causes the liquid to setto an almost solid mass of crystals with total expulsion of the ether.The experiment was carried out as follows.I n a tube, containing 1.83 grams of potassium iodide, 5.0 gramsof mercuric iodide, and 5 C.C.of dry ether, was placed a sealed bulbcontaining 0.22 gram of water, and a small piece of glass rod. Thetube was then sealed, and, on mixing carefully so as not to breakthe bulb, the liquid compound was obtained with a small surfacelayer of ether. The bulb was then broken by a jerk, and the tubequickly became filled with a mass of yellow crystals insoluble in theether.Solution of Potussium Iodide and Mercuric lodide in a Mixtureof Ether and Water.-As stated above, the addition of water to thecompound KHg13,4Et,0 causes the precipitation of the saltKHg13,H,0, and on the further addition of water the crystals7 L 2300 MARSH : PHENOMENA OBSERVED WHEN POTASSIUMbecome soluble in aqueous ether, to separate again on warming thesolution.By continuing the addition of water, these crystals nolonger separate on warming, nor does the water cause the separationof ether, but eventually red mercuric iodide is precipitated. Thisoccurs when the amount of water added is just double the voluiueof the ether; the addition of a little more ether clears the solution.With a larger amount of ether than four molecules to one of thesalts, the addition of water may cause the liquid to separate intotwo layers. When there is separation, it is found that there is atemperature, the critical point, below which complete mixture takesplace, and above which there is a separation into layers. Thiscritical temperature depends on the concentration of the doublesalt in solution and the relative amounts of ether and water.Itis to be noted further that, whereas the addition of water to themixture of potassium and mercuric iodides brings about partialsolution with absorption of heat, the addition of ether brings aboutcomplete solution with evolution of heat, and the further additionof the water to the aqueous ethereal solution also causes an evolutionof heat. The following example shows the effec:t of increasingquantities of water, the amounts of potassium iodide, mercuriciodide, and ether being constant. One molecular proportion ofpotassium iodide and one of mercuric iodide were mixed with 12.5molecular proportions of water ; the temperature fell 2O, the solutionnot being complete.On addition of 12.5 molecular proportions ofether, the temperature rose loo, the solution being now complete.The critical point of this solution was 31O. Successive additions of12.5 molecular proportions of water were made, and a rise of tem-perature in each case was noticed until it became too small to bemeasured. The critical point was determined after each additionof water. The results are illustrated by the curve in Fig. 1. Itwill be seen that the critical point falls to a minimum and risesagain. It was found that the solution of lowest critical point frozewhen the temperature was reduced to about -15O. The com-position of the liquid of lowest critical point, and therefore also ofthe frozen mass, is represented nearly by the rather complex formulaKHgI3,12-5E~0,75H,O.The volume relations are more simple,being nearly 1 vol. KHgI, : 3 vols. Et20 : 3 vols. H20. When partlymelted and no longer adhering to the sides of the tube, the solidmass floats on the surface of the liquefied part.There is a further point to be noted with regard to the criticalpoint. It is found that, when the most concentrated solution,namely, that which has the critical point of 31°, is heated, aheavy liquid layer separates at the bottom of the tube, increasingin amount as the temperature rises, and being redissolved as thMERCURI-IODIDE IS DISSOLVED IN ETHER AND WATER. 2301temperature falls, until at 31° i t disappears altogether.On theother hand, all the other solutions, when heated above their criticalpoints, expel a light layer, which increases with the temperatureand is re-absorbed by the bulk of the liquid just below the criticalpoint. It will thus be seen that a solution of one molecular pro-portion of potassium mercuri-iodide in 12.5 molecular proportionsof ether and 12.5 of water expels, on warming, a heavy liquid layer,whereas a solution containing the same quantities with an additionof 12.5 molecular proportions or more of water expeIs, on warming;FIG. 1.0- 52 4 6 8 10 13 14Volume of tenter.a light liquid layer. I f , now, we take an intermediate amount ofwater, namely, 18.75 molecular proportions, the other quantitiesremaining the same, a solution is obtained which, on warming,expels both a heavy liquid layer and a light one, so that threedifferent liquids appear in the tube.I n one experiment a sealedtube was used which contained 5-53 grams of potassium iodide,15.1 grams of mercuric-iodide, 10 C.C. of water, and 44.2 C.C. of" wet " ether. This solution is homogeneous a t the ordinary tem-perature, and between 50° and 60° a, good separation is obtaine2302 MARSH : PHENOMENA OBSERVED WHEN POTASSIUMinto three liquid layers. These layers are permanent and notaltered by shaking while the liquid is still hot, but on cooling theyform again a homogeneous solution.It is possible to obtain other solutions which, on heating, givethree liquid layers and have concentrations different from that justmentioned.The one which was first obtained contained equalmolecular proportions of water and ether. As has already beenstated, with the concentration of 1 to 12.5, a lower layer begins toseparate at 31O; with the concentration of 1 molecular proportionof salt to 25 molecular proportions of ether and 25 of water, theupper layer separates above the critical point Oo. By trying con-centrations between these two limits, it was found that with theconcentration of 1 molecular proportion of potassium mercuri-iodideto 17.3 molecular proportions of water and 17.3 of ether, the solutionseparated into three layers. I n a calibrated tube, 1-66 grams ofpotassium iodide, 4.54 grams of mercuric iodide, 2.6 C.C. of water,and 18.2 C.C. of ‘ I wet ” ether were sealed.The calculated volumeof the constituents is 22.0 C.C. The volume found on mixing was21.4 c.c., so that there was a slight contraction. The tube was thenheated to different temperatures, and the volumes of the solutionswere determined. The curve plotted from the measurements isgiven in Fig. 2. In what follows, the top layer is termed“ ether ” solution, the middle layer “ mixed ” solution, andthe lower layer “ water ” solution. At 22O, “ ether ” solutionbegins to separate, and increases in amount as the tempera-ture rises. A t 33-5O, water ” solution also begins to separate,and both layers increase with the temperature. At 51’5O, the“ mixed ” solution disappears, and only two liquids are present.These two liquids do not appreciably alter in volume on heatingfurther to above 70°.Correction was made for expansion by heat,which was regular, and nearly the same as the expansion of etheritself. In order to determine the amounts of mercuric iodide andpotassium iodide in the water layer, a tube was taken with a bulbof 4 C.C. capacity at one end, the mixture in the tube being madeup of 2 molecular proportions of potassium mercuri-iodide (12.4grams) to 25 of ether and water. On heating, the heavy aqueoussolution just filled the bulb at 63O. The tube was cooled withoutmixing the two solutions, opened, and the solutions separated.The aqueous solution measured slightly less than 4 C.C. The mixedsalts contained in it weighed 4-77 grams, of which 1-58 grams waspotassium iodide.The solution contained scarcely any ether, itdid not take fire (water containing 0.5 per cent. of ether takes fire),and had scarcely any odour of ether. It was thus found that anaqueous-ethereal solution of the salts, which is homogeneous wheMERCURI-IODIDE IS DISSOLVED IN ETHER AND WATER. 2303cold, separates, on warming, into a, '' water " solution nearly freefrom ether, and an ether " solution which, from the volnmes ofthe two solutions, can contain but little water.I n order to determine how the mercuric and potassium iodidesare apportioned in all the three layers, a solution was made whichgave three layers at a temperature below the boiling point of ether.FIG. 2.2018161412w fc 10wk8642--l-- 31 xed solution.l o o 20" 30" 40" 50" 60" 70"Tempe ratzi re.The three Iayers caii then be produced in a stoppered burette, andrun off and analysed.It was found that with 1 molecular pro-portion of salt to 20 molecular proportions of water and 33 of ether,a separation into three layers is obtained at 2 9 O . The " water "layer measured 0.6 c.c., had a concentration of 1 gram per c.c.,and contained HgI, : KI = 2 : 3 mols. The " middle " layer measure2304 MARSH : PHENOMENA OBSERVED WHEN POTASSIUM6.2 c.c., had a concentration of 0.4 gram per c.c., and containedHgI, : KI= 1 : 1 mol. The (( ether ” layer measured 31 c.c., had aconcentration of 0.1 gram per c.c., and contained HgI,: KI=7 : 6mols.It will be noticed that the ((water” solution contains more,and the I‘ ether ” solution less, potassium iodide than is representedby the simple molecular proportions HgIz: KI.It was found that(‘ wet ” ether will dissolve mercuric iodide and potassium iodide inany proportions between the lower limit K I : HgI, and the upperlimit KI: 2Hg1,. The upper limit of solubility of water isKI: HgI,, whilst there is, of course, no lower limit.There seems no doubt that this separation of a homogeneoussolution into layers on warming is associated with the temperaturechanges which occur on making the solutions. There are fouroperations, three of which occur with evolution of heat, and onewit.h absorption of heat. I n the first place, mercuric iodide andpotassium iodide together dissolve in water with absorption of heat.The same salts dissolve in ether with evolution of heat.Further,ether dissolves in the water ” solution with evolution of heat, andwater also dissolves in the ((ether” solution of the salts withevolution of heat. It would be expected that the effect of raisingthe temperature would be to assist the change which occurs withabsorption of heat, and to prevent those changes which occur withevolution of heat. Thus either ether will be expelled from solution,which happens at low concentrations, or water will be expelled,which happens at high concentrations, or both ether and water willbe expelled, and further the salts will be expelled from the (( ether ”solution into the (( water ” solution. There is thus eventually pro-duced, at a sufficiently high temperature, a strong aqueous solution,together with a weak ethereal solution of the two salts.Thesechanges are reversed on cooling. I f not shaken, however, thesolutions may be kept apart when cooled; theyfmix then on shakingwithout change of temperature or volume. The great concentrationof salts in the “water” layer is well shown by heating a tube,containing 1 molecular proportion of salt to 12.5 molecular pro-portions of water, to about 70°, and then, without shaking, coolingrapidly to Oo. The “ water ’’ layer now becomes filled with crystalsof the double salt mixed with the red crystals of mercuric iodide.Compounds of Two Haloid Salts wit?& Ether.A number of compounds analogous to the compound KHgI,,QEt,Owere also prepared.The alkali-metal iodides form liquid com-pounds with mercuric iodide and ether, with the exception oMERCURI-IODIDE IS DISSOLVED IN ETHER AND WATER. 2306rubidium and caesium iodides.following f ormulze :The compounds obtained have t,heNaI,HgT,,G Et20KI,Hg I,,4Er20LiI,HgT,. 6E t,,O Li Br, HgT2,4Et,O [ LiC1,HgI2 '13LiI, HgBr,,5 Et,O[LiI,HgCI, 93 LiBr,HgCI,,Et,O '1 [LiCI,HgCl, '13Li Br, Hg Br,, 4 E t20 1 t i C1, Hg Br,, E t,O ?LiI, AgI,3Et.,OLiI,CuI,4 Et,OThe compound KI,HgI,,4Et20 is described on p. 2298. Theamount of ether (4 molecules) is approximately correct at theordinary temperature, but the compound is affected by a rise oftemperature with loss of some of the ether. This effect is found tobe a general one for this class of substances even when they arecontained in sealed tubes; it is small in the case of the lithium andsodium mercuri-iodides.The experiments which are now to bedescribed are not therefore intended to furnish accurate analyticaldata, but rather to show how the substances were obtained. Theyindicate also that the constituents are combined at the ordinarytemperature in approximately simple molecular proportions, theamount of the solvent being limited to six molecules or less. Theliquids can, however, hardly be regarded as " definite " compoundsin the ordinary sense, nor are they ordinary solutions, since they aresaturated both for salt and for solvent. They seem t o be of anature intermediate between a solution and a chemical compound.C o r n p o d s of Iodides with Mercuric Iodide and Ether.Lithium Zodide.-Lithium iodide alone is readily soluble in dryether, although not in undried and ((wet" ether.It does not,however, form a liquid compound with a limited amount of etherin presence of excess of ether.1.4 Grams of lithium iodide and 5.05 grams of mercuric iodidewere mixed in a stoppered burette with 10 C.C. of dry ether, whenall dissolved rapidly, forming two liquid layers. The volume ofthe solution was 8.15 c.c., and that of the upper ether layer 2.55 C.C.The latter left, on evaporation, 0.015 gram of solid residue, con-sisting of lithium mercuri-iodide, LiHgI,. Hence the liquid com-pound contained 1.387 gra.ms of lithium iodide, 5-038 grams ofmercuric iodide, and 7.45 C.C.of ether in 8-15 C.C. From thesenumbers is derived the formula LiI,HgI,,6EL20, and the specificgravity 1-461Sodium Zodide.-l*53 Grams of sodium iodide and 3.67 grams o2306 MARSH : PHENOMENA OBSERVED WHEN POTASSiUMmercuric iodide were sealed in a tube with 6 C.C. of dry ether. Thecontents of the tube liquefied readily on shaking, with the exceptionof some sodium iodide, of which excess was taken by accident. Theether not required was 0.8 C.C. The formula of the compoundformed is NaI,HgI,,GEt,O.Rubidium Zodide.-Rubidium iodide and mercuric iodide incontact with dry ether gave no liquid compound. There is noapparent action at first, but after some days the red mercuric iodidedisappears, and its place is taken by a yellow, crystalline substance.Caesium Zodide.-Cwium iodide and mercuric iodide gave noliquid compound with ether, and after several months most of themercuric iodide appeared to be unchanged.Silver Zodide.-Silver iodide and mercuric iodide in ether do notappear to suffer any change.Strontium Iodide.-l.44 Grams of strontium iodide and 3-67grams of mercuric iodide, with 6 C.C. of dry ether, liquefied andcombined with 2-63 C.C.of the ether; hence the formula of theliquid compound is SrI2,2HgI,,6E~O.Aluminium Iodide.-Aluminium iodide and mercuric iodide didnot give any liquid compound with ether, but the colour of themercuric iodide disappeared with the formation of a yellow pre-cipitate and, after a time, of large, colourless crystals.Hydrogen Ibdide.-1'27 Grams of mercuric iodide were mixedwith 3 C.C.of dry ether, and dry hydrogen iodide was passed inuntil the mercuric iodide just dissolved. Two layers of liquid wereformed, and the upper layer of unused ether measured 2.25 C.C.The probable formula of the compound is HI,Hg12,3Et20.Tetramethylamrrwnhm Iodide.-Tetramethylammonium iodideand mercuric iodide suffer no apparent change in dry ether afterseveral months.Ammonium Iodide.-The compound of ammonium iodide andmercuric iodide with ether differs from the other compoundsdescribed, in that its composition is different at different tem-peratures. 0-584 Gram of ammonium iodide and 1.83 grams ofmercuric iodide, with 3 C.C. of dry ether, gave two liquids, theunused ether measuring 0-8 C.C. This agrees with the formulaNH,I,HgI,5Et20.At about 80°, 1 molecule of ether is expelledfrom the lower to the upper layer in the sealed tube. Thus thecompound NH,I,Hg12,4Et,0 is left.If wat'er is added to ammonium and mercuric iodides dissolvedin excess of ether, no crystalline hydrate separates, but the wateris absorbed to a certain amount, and then any excess of waterremains undissolved as a light layer floating on the heavy ethersolution. The water layer contains very little of the salt dissolvedMERCURI-IODIDE IS DISSOLVED IN ETHER AND WATER. 2307Compounds of Bromides with Merczlric Bromide and Ether.Lithium Bromide.-O*4 Gram of lithium bromide and 1.8 gramsof mercuric bromide were sealed in a tube with 3 C.C.of dry ether.The mixture readily liquefied, and formed two layers. The amountof ether in excess was 1.02 c.c., hence the formula of the liquidcompound is LiBr,HgBr,,4Et20.Sodium Bromide.-Sodium bromide and mercuric bromide gaveno liquid compound with ether.Ammonium Bromide.-l.43 Grams of ammonium bromide and5.3 grams of mercuric bromide were sealed in a tube with 5.5 C.C.of ether. The salts liquefied, but not quite completely, and required3-66 C.C. of ether.NH4Br,HgBr,,2'5Etz0.This compound, however, like the corresponding iodide, loses etherwhen warmed in the sealed tube, leaving not another liquid com-pound, but a solid mass, with loss of probably all the ether. Thema-ss slowly unites again with the ether when cold. Further, whenthe liquid compound itself is cooled to about loo, it sets to a solidmass of colourless crystals without any loss of ether.This agrees with the formulaLithium Chloride arid Mercum'c Chloride.0.42 Gram of lithium chldride and 2-71 grams of mercuricchloride were sealed with 3 C.C.of dry ether in a tube. No liquidcompound was obtained, but, on long keeping, crystals formed inthe tube.Hised Halogen Salts and Ether.Lithium Bromide, Mercuric irodide, and Ether.-O*45 Gram oflithium bromide and 2-27 grams of mercuric iodide were mixed with3 C.C. of dry ether in a sealed t,ube. The salts liquefied,taking up 2-15 C.C. of ether. From these numbers the formulaLiBr,HgIz,4Et20 is derived.Lithium Iodide, Mercuric Brorn.de, and Ether.-@76 Gram oflithium iodide and 2-15 grams of mercuric bromide liquefied incontact with 4 C.C.of dry ether, and required 3-14 C.C. for solution;hence the formula of the compound is LiI,HgBr2,5Et2O. Neitherlithium chloride with mercuric iodide nor lithium iodide withmercuric chloride gave any liquid compound with ether.Lithium Bromide, Mercuric Chloride, and Ether.-@85 Gram oflithium bromide and 2.65 grams of mercuric chloride were mixedwith 4 C.C. of dry ether. The action was slow and did not appearcomplete, but partial liquefaction occurred. The amount of ethertaken up was 1.06 c.c.; hence the probable formula of the compoundis LiBr,HgCl,,EhO2308 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALLithium Chloride, Mercuric Bromide, and Ether.--@21 Gram oflithium chloride and 1.8 grams of mercuric bromide became pastyin contact with 2 C.C. of dry ether without completely liquefying.The amount of ether taken up was 0.7 c.c.; hence the probableformula of the compound is LiCl,HgBr2,Et20.All the liquid compounds with ether mentioned above contain amercury salt as one constituent. The following are examples ofliquid ether compounds, where silver, lead, and copper iodides takethe place of mercury salts.Lithium Iodide, Silver Iodide, and Ether.-l.82 Grams of lithiumiodide and 2.67 grams of silver iodide were sealed with 6 C.C. of dryether in a tube. Liquefaction took place rapidly, two layers wereformed, and 3-6 C.C. of ether were taken up. From this the formulaLiI,AgI,SEt,O is deduced.Lithium Iodide, Copper Zodide, and Bther.--1*45 Grams oflithium iodide and 2-05 grams of cuprous iodide were sealed in atube with 5 C.C. of dry et,her. A liquid compound was obtained,but was not clear. The ether not used was 0.85 C.C. Hence theprobable formula of the compound is LiI,CuI,4EhO.Lithium Iodide, Lead Iodide, and Ether.-O.87 Gram of lithiumiodide and 2-62 grams of lead iodide were sealed in a tube with4 C.C. of dry ether. Ether was absorbed, and the compound formedwas solid and crystalline. It melted partly on warming, but a clearliquid was not formed. The composition is doubtful ; apparentlybetween 3 and 4 molecules of ether are required.UNIVERSITY MUSEUM,OXFORD

ISSN:0368-1645    

DOI:10.1039/CT9109702297

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

2308 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALCCXLII.-TlZc Relation between the Crystal St uwct tireand the Chemical Composition, Constitution, andConjguration o f Organic Suhstan ces.By WILLIAM BARLOW and WILLIAM JACKSON POPE.DURING the last few years the authors have investigated a novelmethod of studying the relations between crystalline and molecularstructure, and have demonstrated the existence of a very simplerelation between the two species of structure in a. great variety ofcases (Trans., 1906, 89, 1675; 1907, 91, 1150; 1908, 93, 1528);the principles involved in the method referred to were brieflysummarised in the introduction of the last-mentioned communi-cation. One of the chief results of this work has been to demonstratSTRUCTURE AND THE CHEMICAL COMPOSITlON, ETC, 2309that, in a given crystalline substance, the volumes appropriatedby the spheres of influence of the different atoms contained in theniolecule are approximately proportional to the numbers represent#-iiig the respective fundamental valencies ; this conclusion has beenindependently verified for hydrocarbons and their simple derivativescontaining oxygen or nitrogen in the liquid state by Le Bas (Trans.,1907, 91, 112; Phil.Mag., 1907, [vi], 14, 324; 1908, 16, 60). Thelatter author, indeed, carries the valency law a step further byshowing that throughout a series of liquid hydrocarbons, undercorresponding conditions, the atomic volumes are directly pro-portional to the numbers representing the fundamental valencies ofthe elements carbon and hydrogen.I n view of the close relation which has been shown to existbetween the sum of the fundamental valencies of the atoms com-posing the molecule-the valency volume-and the crystallinestructure affected by the substance, it is convenient to deriveconstants for related series of substances which are simple functionsof the valency volume and of the crystalline structure as expressedby the geometrical data.We have therefore introduced the swalled“ equivalence parameters,” x, y, and z , which are the lengths of theedges of a parallelepidon, of which the volume is the valency volume,TV, and of which the relative linear and angular dimensions accordwith the axial ratios and the interaxial angles (Trans., 1906, 89,1681) ; the equivalence parameters are calculated as follows :.l: = y76’ W y = X/CL and z = cy.c sin A sin p sin y’The important nature of the information t o be obtained by theaid of the equivalence parameters has been fully demonstrated inour previous papers, and by Jaeger (Trans., 1908, 93, 517),Jerusalem (Trans., 1909, 95, 1275), and Armstrong (this vol.,p.1578).I n the present paper we propose to discuss the close-packedassemblages representing the molecular composition, constitution,and configuration of the paraffinoid, ethylenic, and acetylenic hydro-carbons. As a result of this investigation we shall be able t o showthat, adopting the same principles as have been previously laiddown, each hydrocarbon has its own specific kind of structural unit,and that geometrical peculiarities are distinguishable in theappropriate assemblages corresponding with the presence in themolecule of single, double, and triple bonds between carbon atoms.It will further be shown that the configurations derived for thevarious hydrocarbons by closely packing spheres of magnitudesappropriate for representing the spheres of influence of their atomsare in accordance with the conclusions of van’t Hoff and Le Be2310 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALconcerning the environment of a methane carbon atom.Finally,it will be shown that a process of simple adjustment furnishes ageometrical interpretation of polymerisation and isomeric change,such, for instance, as the conversion of acetylene into benzene. Asa preliminary t o the main argument, and in justification of themethods employed, a passing reference may be made to one or twosimple considerations and the data supporting them.Concerning the legitimacy of attributing to carbon a sphere ofatomic influence four times as large as that of hydrogen, little morenow remains to be said.Since we first drew this conclusion, Le Bashas conclusively proved the atomic volume of carbon to be fourtimes that of hydrogen, and Jerusalem has shown the same relationto hold approximately as between crystalline substances which arenot examined under strictly corresponding conditions. Most of thehydrocarbons of the series with which we have now to deal are,however, either liquid or gaseous under ordinary conditions, andtherefore yield no crystallographic data for employment as a directexperimental check.For our present purpose it is consequentlynecessary to use crystallographic data referring to the halogenderivatives of hydrocarbons, and to rely on them to furnish thenecessary check on the dimensions of the hydrocarbon assemblagesdscribed. The legitimacy of the use of these derivatives for thispurpose depends on our previous conclusion that the spheres ofatomic influence of hydrogen and the halogens differ but slightlyin volume when contained in the same molecular complex (Trans.,1906,89,1679), although the sphere of atomic influence of hydrogenis somewhat smaller than those of the halogens (Trans., 1907, 91,1197).That the spheres of atomic influence of hydrogen and thehalogens have approximately the same valency volume may beconveniently demonstrated by showing that the chemical substitutionof a halogen atom for one of hydrogen in a crystalline substance isfrequently not accompanied by it profound change in axial dimen-sions; in the instances quoted below, it will be seen that thegeometrical change accompanying the substitution in question isin general greater than that ordinarily observed in cases of iso-morphism, but not so great as to obscure the obvious morphotropicrelationship. The comparatively large change in axial dimensionswhich is in general thus presented, and also the rarity of suchinstlances, must be attributed to the sphere of atomic influence ofhydrogen differing appreciably in magnitude from those of chlorine,bromine, or iodine, the latter being much more nearly of the samesize; the discrepancy in volume between the spheres of hydrogenand of the halogens is, however, not sufficient to necessitate theemployment of different sizes of spheres of influence for thosSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2311elements in the construction of the close-packed assemblagesdescribed below.The substitution of hydrogen by bromine, unaccompanied byconsiderable changes in axial dimensions, is illustrated by the datafor the monosymmetric pentabromoethane and the orthorhombichexabromoethane (Trans., 1906, 89, 1682) :CHBr,*CBr, ...........CBr,*CBr, ...............a : b : c=0.5650 : 1 : 0'3118 ; 8=91"19'n : b : c=0*5639 : 1 : 0'3142 ; /3=90°A similar case is presented by the orthorhombic Ir-sulphonylchlorides and bromides of camphor and of a-bromo- and a-chloro-camphor (Kipping and Pope, Trans,, 1893, 68, 548; 1895, 67,367) :d-CIoH1,O*SO,C1 ..............d-C,oH,,0*S02Br ...............d-C,oH,,OBr~SO,Cl ..........d-C,,H,,OCl~SO,Br ..........a : h : C = 0 9980 : 1 : 1.0368a : b : c=0.9816 : 1 : 1.0249cc : b : c=0.8912 : 1 : 1.0518cc : b : c=0*8795 : 1 : 1.0494The axial dimensions of the monosymmetric p-azoxytoluene andits monobromo-derivative are almost identical (v.Zepharovitch,Zeitsch. Xryst. Min., 1889, 15, 214)) and a similar relationshipholds between the values for the orthorhombic ptolyl-mono- anddi-chloro-methylsulphones (Brugnatelli, Zeitsch. Kryst.Min., 1892,20, 604-605) :p-Azoxytolnene .............................Rromo-~-azoxytoluene ....................p-Tolylmonocliloromethylsul~~honr. ...11-Tolyldichlorornethylsulphone .........CL : h : c=1'4971 : 1 : 1.0196 ; 8=75"30'n : h : c=1'5194 : 1 : 1 01 ;ci : b : c-0'6070 : 1 : 0.7865n : b : c=0'5324 : 1 : 0-79138=75"28'30"Acetamide is rhombohedra1 with a : c = 1 : 0.5916 (Kahrs,Zeitsch. Kryst. Min., 1905, 40, 476); on referring the substance torectangular axes by changing the indices (loo}, { 101 ), and f 1 1 O}to { l l O } , (301}, and (301) respectively, the values are obtained as :c6 : b : c = 1 6904 : 1 : 0.9759 ; /3=90".Dibromoacetamide is monosymmetric with a : B : c=1.6887 : 1 : 1.2785, @ = 87O2' (Fock, Zeitsch.R?yst. illin., 1888, 14,538); when the transposition involved in changing the indices of{ 203) t o { 101 } is made, the axial ratios are obtained as a : b : c =1.6887 : 1 : 0.8625, @=87O2'. The change of indices here made islegitimate, because the form { 203} is actually observed. Tribromo-and trichloro-acetamide are also monosymmetric, and exhibitthe axial ratios a: b : c = 1.7339 : 1 : 0.8636, /3=79O37/, and1-7485 : 1 : 0.8490, @=78O36' respectively. The four sets of axialratios show a fairly close agreement.The orthorhombic monochloro-pbenzoqu.inone exhibits the axialratios, a : B : c = 1.7461 : 1 : 0.9619 (Fels, Zeitsch. Kryst. Min., 1903,37, 479); these ratios, expressed in the form b : c : u2312 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTAL1.0396: 1 : 1.8153, closely approximate to those of the mono-symmetric dichloro-p-benzoquinone (Fock, Z ~ i t s e l ~ .Kryst. Min.,1883, 7, 40), namely, 0 : 7,: c=1.0920: I : 1.8354, P=89O11',and dibromo-y-benzquinone (Fels, loc. cit.), which exhibitsa : b : c = 1.0941 : 1 : 1.8229, /3=92O32/. The three substancesare, however, pseudohexagonal, a.nd the morphotropic relationbet'ween them is probably even closer than is indicatedby the above axial ratios. Thus, on changing the forms(lor), { l O l } , {loo}, and { 103) observed on dibromo-p-benzoquinoneto {OOl}., {101}, {103}, and (100) respectively, the axial ratiosbecome a: b : c =1.7416 : 1 : 0-9491, /3=90°41'. These valuesapproximate much more closely to the original ones given abovefor monochloro-p-benzoquinone than do those stated by Fels.It isin any case clear that, contrary to the views of Griinling (Zeitscli.Kryst. illin., 1883, 7, 582) and of Fels, very little change in axialdimensions attends the passage from monochloro-p-benzoquinone todichloro- or dibromo-p-benzoquinone.In the instances quoted above, the replacement of hydrogen bya halogen atom leads to no very profound change in crystallographicdimensions. The same kind of relation its is thus expressed mustbe looked for amongst halogen derivatives which are positionisomerides, and several instances from amongst such substances maynext be quoted.The di- and tri-halogen derivatives of camphor have been verycompletely examined by (1) v.Zepharovitch (Zeitsclh. Kryst. Min.,1883, 7, 588), (2) Cazeneuve and Morel (ibid., 1888, 14, 267), (3)Kipping and Pope (Trans., 1895, 67, 371), and (4) Armstrong andLowry (ibid., 1898, 73, 579). The close morphotropic relationshipbetween these orthorhombic substances becomes evident on inter-changing the dimensions b and c in the data (1) and (2), dividingdimension b by two and writing 7, for a, c for b, and a for c in thedata (3), and leaving data (4) as stated by Armstrong and Lowry;the following values are thus obtained:(1) aa-Dibromocamphor . . , . . . . . . . . ,(2) aa-Dichlorocamphor .. . . . . . . . . . .aa-Brornochlorocamphor , . . . . .(3) ax-Dichlorocarriphor ............ax-Dibromocamphor .. . . . . . . . . . .ax- Chlorobromocamphor . . . . . .a*-Bromochlorocamphor . . . . . ,(4) aa-Chlorobromocamphor . . . . . .Baa-Dibromochlorocainphor . . .Original.n : b : c .05'925 : 1 : 0-51430-8074 : 1 : 0'54480*8040 : 1 : 0'52280.6933 : 1 : 0.32970.6860 : 1 : 0.33230.6884 : 1 : 0.83010'6861 : 1 : 0'331715338 : 1 : 1'90201'4627 : 1 : 2.1332Transposed.a : b : c .1.5409 : 1 : 1.99431.4830 : 1 : 1.83651.5379 : 1 : 1.83551'5160 : 1 : 2.102915148 : 1 : 2.08561.5074 : 1 : 2'06421.5045 : 1 : 2.06841.5338 : 1 : 1.90201.4627 : 1 : 2.1332Jaeger has shown (Zeitsch. 2i'ryst. Min., 1904, 38, 570) that themonosymmetric position isomerides, the 1 : 2 : 4- and the 1 : 3 : 4-triSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2313bromotoluenes, have almost identical axial ratios, namely, a : b : c =3.5283 : 1 : 4.1958, and a : b : c =3*5470 : 1 : 4.2603,I3 = 58O551, respectively.A large number of instances similar to those quoted above mightbe selected from the crystallographic literature, but the above willsuffice to confirm our previous conclusion that the sphere of atomicinfluence of hydrogen differs but slightly in volume from those ofthe halogen elements, and consequently that they are all representedin the close-packed, homogeneous assemblage with sufficientexactness by spheres of the same size. I n the following pages weshall therefore assume that the crystallographic configuration ofany hydrocarbon can be presented under some conditions by itshalogen derivatives, and, when crystallographic data are availablefor any of the latter, shall directly employ those data for checkingthe correctness of the assemblage derived for the hydrocarbon itself.I n connexion with the concluding portions of this communication,in which the occurrence of polymerisation and isomeric change istreated, it may possibly be suggested that no method of discussioninvolving considerations connected with crystal structure can bejustified, inasmuch as such changes occur in general in the liquidor even in the gaseous state. To this objection the reply is madethat the great mass of work done during recent years on secalledliquid crystals has greatly extended the domain of crystal structure,It is now known that in those liquid substances which exist in theliquid crystalline condition, tracts, so large as to be readily discernedmicroscopically, exist in which the regularity of arrangementexhibited by solid, crystalline structures is present.These tractaare continually forming and disappearing, and their Occurrenceindicates clearly that in these mobile liquids the particles aggregatethemselves together in masses which, measured on a molecular scale,are of enormous extent, and in which very complete regularity ofstructure prevails. Since, in such instances as these, the eye candiscern the existence of a liquid, crystalline structure, it is legitimateto assume that in liquids generally, arrangements of parts, com-parable in regularity with crystalline structures, are being con-tinually formed and dissolved, although possibly not to such anextent as in the cases of known liquid crystals.The occasionaljuxtaposition of parts in orderly close-packed arrangement thuspremised is all that is required to legitimise the discussion ofisomeric change in connexion with crystalline structure./3=58O47f,Methane.As a preliminary to an attempt to apply the methods which wehave previously described to the elucidation of the configurations'VOL. XCVlI. 7 2314 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALand properties of the paraffins, it is necessary briefly to enumeratethe available chemical and crystallographic facts and conclusionsbearing on the configuration of the simplest paraffin, methane.The following may be quoted as sufficient to lead to the constructionof the homogeneous close-packed assemblage of spheres which repre-sents this hydrocarbon.(1) I n accordance with the conclusions respecting valency whichwe have previously drawn (Trans., 1906, 89, 1723), the space appro-priated in the methane assemblage by each carbon atom shouldbe four times as large as that appropriated by each hydrogen atom.(2) Carbon tetrabromide, CBr,, possesses the same configurationas methane, and its assemblage will be represented by the samespheres.The halogen derivative is dimorphous, crystallising above47O in the cubic system (Rothmund, Zeitsch. physikal. Chem., 1897,24, 712) and at the ordinary temperature in the monosymmetricsystem. Carbon tetrachloride and tetraiodide crystallise in thecubic system.(3) Stereochemical facts indicate that in the free methanemolecule the four hydrogen atoms are situated at the apices of aregular tetrahedron described about the carbon atom, and that thistetrahedral environment of the methane carbon atom must beregarded as surviving a substitution of one or more of the fourhydrogen atoms by other atoms or radicles.(4) The assemblage representing methane, built up in accordancewith the principles laid down in previous papers, should be capableof geometrical modification so as to yield assemblages representingother paraffins ; the geometrical process thus involved should bestrictly illustrative of the practical methods by which methane canbe converted into these homologous paraffins.It should thus bepossible to derive one assemblage corresponding in composition,constitution, and configuration with each paraffinoid hydrocarbon.An extension of the same method should lead to the derivation ofcharacteristic assemblages for other aliphatic hydrocarbons andcompounds other than the paraffins ; the applications should embraceall the varieties of isomerism, and express the facts that have ledto the conception of the asymmetric carbon atom.An assemblage which, both as a whole and when partitioned,fulfils the above and. other conditions concerning methane isarrived at in the following manner. Alternate layers are removedfrom a cubic closest-packed assemblage of equal incompressible butdeformable spheres (Trans., 1907, 91, 1152), regarded as composedof layers of square arrangement (Fig.l), the remaining layers beingcaused to retain their original positions. The resulting skeletonassemblage, which has tetragonal symmetry, is shown in plan anSTRUCTUICE AND THE CHEIdtCAL COMPOSITION, ETC. 2315elevation in Figs. 2 and 3 ; the dotted lines which join the centresof nearest spheres inpartitioning of spaceinto equal rightsquare prisms.The next step con-sists in distorting theskeleton assemblageby a contractionalong its fourfoldaxis, accompanied bya compensatory ex-pansion in directionstransverse to thisaxis, so that thesphere centres finallylie a t the corners ofcubes equal in con-tent or volume to theoriginal right squareprisms.The systemthus derived possessesholohedral cubicsymmetry, and iscomposed of sphereswhich do not quitetouch one another;its projection parallelto any cube plane isshown in Fig. 4.This cubic system,like the tetragonalsystem from which itis derived, possessesone-half the densityof packing of theparent assemblage;if, therefore, smallspheres of the samedef ormable material,four times as numer-the three principal directions outline aFIG. 1.FIQ. 2.ous and one-fourth the volume of the original large ones, are forcedinto its cavities, and the whole system is then subjected to com-pression so as to eliminate the interstitial space, the polyhedraproduced from the large spheres will be about four times a.a large ils7 M 2316 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALthose produced from the small ones.I n the skeleton assemblage ofFig. 4, the cavities are as numerous as the spheres; if, therefore, eachFIG. 3.cavity bounded byeight neighbouringspheres can be madeto accommodate agroup of four of thesmall spheres in sucha manner as to givestable equilibriumand to be compatiblewith cubic symmetry,several of the moreessential conditionsfor methane will beobeyed .by the assem-blage.Each cavity of theskeleton assemblagedescribed exhibits sixidentical four-sidedhollows, the centresof which lie on threerectangular a x e sdrawn through thecentre of the cavity,and, in placing atetrahedral group ofthe small sphereswithin the latter, anythree of the hollowswhich lie nearesttogether are selectedfor the reception ofthree out of the foursmall spheres of thegroup, one juttinginto each of theselected hollows.Thefourth sphere of thetetrahedral g r o u pwill then touch thatsphere of the eight of volume four which does not border either ofthe selected hollows, the point of contact being on the cube diagonaSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2317which passes through the centre of this large sphere. The mar-shalling thus arrived at for a cubic unit of the assemblage is theone required; it has yet to be shown what relative orientations ofthe contents of the different cube cells are consistent with cubicsymmetry and what adjustment of the arrangement described willrestore the close-packing which has been impaired by substitutingthe tetrahedral groups of small spheres for one-half of the largerspheres of the closest-packed assemblage.The introduction of the tetrahedral group into the cubic cell inthe manner described lowers the symmetry by destroying three ofthe four trigonal axes of the cell; if cubic symmetry is to survivethe introduction of such a tetrahedral group into each cavity, thoarrangement of the completed assemblage must consequently be ofone of the types in which the trigonal axes do not intersect.TheFIG. 5.mode of ascertaining the relative positions of the non-intersectingtrigonal axes has been already described (Trans., 1907, 91, 1183);its application to the present case leads, in the following manner,to the production of the appropriate type of symmetry for themethane assemblage.In the cubic partitioning of space shown in Fig.4, one trigonalaxis, a, of one cube of the partitioning is drawn and produced inboth directions, so as to pass through a st'ring of cubic cells whichare in contact at their corners (Fig. 5), the latter being centres ofcarbon spheres; in the first selected cube of the part,itioning, thegroup of four small or hydrogen spheres is inserted in its appropriateposition with respect to this trigonal axis. I n any one of the sixcubic cells which make face contact with the first selected cubecell, a single diagonal is drawn, the position chosen being suc2318 BAHLOW AND POPE : THE RELATION BETWEEN THE CRYSTALthat, like c in Fig.6, it is not parallel to the trigonal axis a,already located and does not intersect it. This last drawn diagonalis used as a trigonal axis, and by rotations about it through 120°, theexisting trigonal axis and group of small spheres are transferredto two new positions, so as to locate other trigonal axes and groupsof hydrogen spheres in the system. The latter process is repeatedabout the axes thus located and about subsequently located axes,until all the situations for trigonal axes in their four orientationsand all the positions for groups of small spheres derivable in thismanner have been ascertained ; the minimum distance separatingtrigonal axes of different orientations is that separating the two firstlocated. A diagram showing the relative situations of the axes hasFIG. 6 .been already given(Trans., 1907,91, 1183).As a result of t,hisseries of operations, onetrigonal axis becomeslocated in each cubecell of the cubic par-titioning of space, butthe original tetrahedralgroup of small spheresbecomes transferred tobut one-half of thesecube cells.The cubecells forming the halfsystem, distinguished byeach cell containing atetrahedral group ofsnia.11 spheres, are incontact at their edges only; they have the arrangement of the lightor the dark cubes of the previously described stack of cubes of twokinds (Trans., 1908, 9 3 , 1533, Fig. 1). The skeleton assemblagethus derived has the symmetry of Barlow’s type 1.Only one kind of arrangement possessing cubic symmetry can bearrived at in the manner just. described, but there are two alternativeways in which to complete the assemblage homogeneously by fillingthe unoccupied cavities, which are equal in- number to thoseoccupied, with the tetrahedral groups of small spheres in a mannercompatible with cubic symmetry ; both of these involve slightadjustment of the skeleton assemblage, but no re-marshalling.Thecompletion is in both cases effected by bringing the one-half systemof cubes to the place of the other half system. One of the twoalternative operations consists in rotating the system through 180STRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2319about an axis drawn perpendicular to a cube face and passingthrough the centre of a cube edge, such perpendicular not being adigonal screw axis of the skeleton assemblage; this involves theaddition of digonal rotatioii axes to the original system of trigonalaxes and digonal screw axes, and yields a completed assemblagehaving the symmetry of Barlow’s type 2.The other operation isone performed about a centre of symmetry situated at a cube angle,arid leads to the production of a completed assemblage having thesymmetry of Barlow’s type la (Zeitsch. Krgst. Min., 1894, 23, 10,44). Both assemblages thus derived become very closely packedas the result of a slight adjustment, but the assemblage of type 2,which displays tetartohedral cubic symmetry, appears to be capableby modification of closer packing than the other.It is, moreover,the assemblage indicated by the facts as representing methane;each of the large spheres in it is similarly situated with respect tothe groups of small spheres, whilst in the assemblage of type lathe large spheres form two seh, the members of one of which differin environment from those of the other. The latter type ofassemblage probably has a practical application, although not inthe present connexion.With respect to the relative orientation of the tetrahedral groupsof small spheres in the assemblage of type 2, it is to be noted thatthe groups contained within the one half set of the cubes of thepartitioning are related by a simple operation, besides that ofrotation about a digonal axis, to those contained within the otherhalf set.The relation consists in the existence of four similartranslations having the four directions of the sets of trigonal axes.Either of these operates to bring a cubic cell to the place of aneighbouring cubic cell, which is in contact with the first at one ofits corners. I n addition to being identical, the two half systems ofcubes with their contained groups of four small spheres consequentlyhave the same orientation, and the wsemblage as a whole ishemimorphous, like the assemblage of type 1 from which it is derived.It has been already noticed that in order to render the packingclose, a modification or deformation of the whole assemblage mustoccur. The eight large or carbon spheres enclosing a single cavitymay be regarded as forming six indivisible quartettes, one for eachof the six faces of the cubic cell containing the cavity; the fourspheres composing a quartette form two square hollows, one in eachof its opposite faces, and these two hollows communicate with eachother at the centre of the quartette.Where a small sphere occupiesthe hollow on one face, the existence of a digonal axis bisecting thecell face involves the presence of another small sphere in the hollowon the other face of the same quartette, and therefore one half o2320 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALthe quartettes of large spheres in the assemblage are occupied, andthe other half unoccupied, by the smaller spheres. It follows thatsome increase in the closeness of the packing will be likely tosupervene if it is possible symmetrically to adjust the arrangement ofthe larger spheres, without altering the marshalling, in such a wayas similarly to diminish the size of onehalf of the hollows-theunoccupied ones-while slightly increasing the size of the rest-theoccupied ones.Three of the six hollows present in each cavity,namely, the unoccupied ones, will in this event become contracted.Such an adjustment of the larger spheres, which does not alter thetype of symmetry, consists in a slight equal shift of each largosphere along its trigonal axis in either direction; the choice made ofFIG. 7.the direction of shift for any one sphere necessarily determines thedirections for all if the assemblage is to remain compatible withthe coincidence movements of type 2.The amount of shift islimited by the approximation of the large spheres, causing them tocome into contact at points lying on the digonal axes of rotationwhich characterise type 2. An important feature of the change isthat the large or carbon spheres, in shifting, close in around thathydrogen sphere of each tetrahedral group the centre of which lieson the trigonal axis; the position of the tetrahedral groups under-goes slight adjustment during the process.A projection of the resulting assemblage, showing the carbonspherea alone, is given in Fig. 7; the centres of these spheres lie iSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2321four different planes parallel to the plane of projection, and aretherefore distinguished by circles drawn in heavy or light, con-tinuous or broken lines.The adjustment of the positions of thetetrahedral groups which accompanies the shifting of the carbonspheres, and indeed the entire process, is compatible with themaintenance of cubic symmetry ; the existence of the coincidencemovements of the system involves that all the cavities for thereception of the tetrahedral groups remain identical with oneanother.One of the surest indicakions of closepacking is obtained whencach sphere is in contact with, or in very close proximity to, sucha number of surrounding spheres as approaches the maximum. Thenumber of contacts and near proximities in the assemblage underconsideration is as follows: for each of the carbon spheres, 19,namely, 6 with carbon spheres and 13 with hydrogen spheres.Foreach of three-fourths of the hydrogen spheres, 8, namely, 4 withcarbon spheres and 4 with hydrogen spheres; for each of one-fourthof the hydrogen spheres, 7, namely, 4 with carbon spheres and 3with hydrogen spheres. These numbers of ccjntacts approach themaxima, taking into account the different sizes of the componentspheres; they thus afford a proof that the marshalling of theassemblage is compatible with very close-packing.In connexion with the partitioning of the assemblage into identicalmolecular units of the composition CH,, it should be noted thatfour of the thirteen contacts of hydrogen spheres with a carbonsphere are nearly symmetrically distributed over the surface of thelatter; the four hydrogen spheres concerned are thus situated atthe apices of an approximately regular tetrahedron, of which thecentre is the centre of the carbon sphere.The four hydrogenspheres referred to may be identified as follows. In any pseudo-cubic group of eight carbon spheres in the assemblage, the singletrigonal axis intersects two of the eight; one of these makes contactwith a single hydrogen sphere of the enclosed group at its point ofintersection with the trigonal axis. Regarding this carbon sphereas that of the molecular unit, CH,, to be picked out, it is to benoted that the three contacts with it of hydrogen spheres, which,with the one on the trigonal axis, make up the four referred to, arethose of the hydrogen spheres lying in three of the outside hollowsof those faces of the cubic group which have as their commonangular point the centre of the selected carbon sphere.The fourcontact3 of the unit molecular group CH, thus derived do notprecisely mark the angular points of a regular tetrahedron, butthe arrangement of the four hydrogen spheres about the carbonsphere approximates so closely to the regular tetrahedral dispositio2322 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALpremised by the theory of van't Hoff and Le Be1 (Figs. 8 and 9) thatits departure from the latter cannot be clearly indicated in a,diagram; the assemblage is divisible into identical units of the formdepicted. The result of the close approximation to regularity ofthe tetrahedra marked out by the hydrogen sphere centres thusselected is that different assemblages produced by fitting togetherthe molecular units in different orientations will be so nearlyidentical that the equilibrium arrangements to which they pass willbe actually identical.I n this connexion it is instructive to observethat the tetrahedral arrangement is indicated in another manner ;each carbon sphere, before the adjustment, is similarly related toeight cavities, of which the relative positions are those of the angularpoints of a, cube, and the greatest number of these cavities whichcan participate in containing the hydrogen spheres attached to thecarbon sphere is four. Consequently, the most symmetrical modeFIG.8. FIG. 9.of allotment of the hydrogen spheres is for each carbon splierc t oattach to itself four hydrogen spheres contained in four out ofthe eight cavities surrounding it, and for these four cavities to beselected with a, regular tetrahedral disposition. Thus, like thehydrogen atoms in the usual graphic formula of methane, the fourcavities concerned have interchangeable positions with respect tothe carbon sphere to which they relate.It is thus to be finally concluded tha.t the investigation of theclose-packed arrangement of the methane assemblage indicates thatthe molecular units can be so chosen as to have t'he tetrahedralconfiguration depicted in Figs. 8 and 9.The relation thus established between the theory of the tetra-hedral arrangement of the links within the molecule, based on thechemical behaviour of methane and its derivatives, and the concretegeometrical properties of the corresponding close-packed arrange-ment of the spheres of influence of the component atoms is of funda-mental importance. It is worth recapitulating in precise language,because it will subsequently be shown that a relation of the samSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2323nature obtains for the carbon compounds generally; in other words,that a tetrahedral arrangement of the contacts of a carbon sphere ofinfluence with its companion spheres persists after substitution hastaken place. The relation for methane may be thus stated.Represent the carbon and hydrogen atoms of a methane molecule byspheres of the valency volumes 4 and 1 respectively, and form thespheres into groups of five according to the van’t Hoff-Le Be1 theory,each sphere of volume 4 being in contact with four spheres, eachof volume 1, placed around it symmetrically, so that their centresmark the angular points of a regular tetrahedron; it is then foundthat, while preserving the marshalling of the spheres of eachindividual molecular unit, a close-packed assemblage can be formedby fitting the groups together symmetrically, of such a nature thatits geometrical properties are those of the crystalline tetrahalogenderivatives of methane.The following crystallographic data ar0 available i ~ s bearing onthe symmetry and dimensions of the methane assemblage.Carbontetraiodide, CI,, is cubic, and carbon tetrabromide, CBr,, crys-tallises above 46*7O in the cubic system, the crystal class beingknown in neither case. Below 46*7O, carbon tetrabromide crys-tallises in the monosymmetric system, but, as previously pointedout (Trans., 1908, 93, 1530), this modification is referable tothe pseudocubic axial system, a : b : c=1.0260 : 1 : 1, a=90°16‘,P = y = 90°33’ ; the monosymmetric form thus scarcely differs indimensions from the truly cubic one, and both indicate the cubicmarshalling of the assemblage. On replacing each hydrogen spherein the methane assemblage by the group CH,Br, in accordance withthe second geometrical property of close-packed assemblages (Trans.,1907, 91, 1204), tetrabromo-PB-dimethylpropane, C(CH2Br)*, isobtained; as Jaeger has found (Trans., 1908, 93, SZO), this sub-stance may be regarded as pseudocubic, with the axial ratiosa : b : c=1.0484 : 1 : 0‘9472, B=9Oo45’.The cubic marshallingof the methane or carbon tetrabromide assemblage thus survivesthe symmetrical introduction of four methylene groups, CH,, intoeach molecular unit, CBr,, in accordance with the second geometricalproperty.I n connexion with the assemblage attributed above to methaneand to its fully substituted halogen derivatives, it may be noted thatiodoform, CHI,, is described as hexagonal with a: c = l : 1.1084(Pope, Trans., 1899, 75, 46). It is evident that the symmetry ofthe space arrangement of the methane assemblage may be loweredwithout any appreciable alteration of the relaOive situations of thespheres by a partial substitution of the spheres representinghydrogen atoms which leads to the production of an arrangemen2324 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALappropriate for iodoform.I n order to trace the probable effect ofsuch a substitution, it is convenient to work with an ideal less closely-packed assemblage of higher symmetry, from which the methaneassemblage may be regarded as derived. Let the centres of thecarbon spheres occupy precisely the points of a cubic space-lattice(Fig. 3), and let each of the tetrahedral groups, CH,, which arenow to be of completely regular configuration, be rotated fromthe orient-ations which they present in the closest-packed assemblage,so that the centres of the small spheres all lie on trigonal axes;the system thus consists of units of the composition CH,, less closelypacked, but all similarly orientated.Next substitute iodine spheresfor three of the four hydrogen spheres of each unit, without alteringthe positions of the centres, in such a way that the new units, CHI,,are all similarly orientated; the result is to destroy threefourth ofthe trigonal axes, and to leave only those which contain the centresof the unsubstituted hydrogen spheres. On performing finally therotations and adjustments requisite to restore the closest-packedcondition prevailing in the methane assemblage, threefourths of thesurviving trigonal axes are destroyed. The closest-packed wem-blage thus arrived at has rhombohedral symmetry and is pseudo-cubic.In the assemblage just derived let the dimension c be three timesthe distance between the centres of carbon spheres lying on the sametrigonal axis ; the distance separating these centres along directionsperpendicular both to this axis and to a face diagonal of a cube ofthe pseudocubic partitioning will be approximately J 2 .c / 3 . I f thelatter distance is taken as a/2, the axial ratio is obtained as :a:c=2J3:3=1:3/2JZ=l :1*0606.This ratio is not far removed from that of iodoform, and it istherefore established that the rhombohedral form displayed by thecrystalline substance may, like the rhombohedral assemblage sug-gested, be pseudocubic.The Normal Homologues of Methane.The most obvious method of constructing assemblages representinghydrocarbons homologous with methane consists in symmetricallyremoving one or more hydrogen spheres from the groups of fourcontained in the assemblage of the parent hydrocarbon, and then,by appropriate adjustment of the spheres remaining, to close upthe gaps which have been produced.Thus, an assemblage of the empirical composition CH3 may bederived by symmetrically removing a hydrogen sphere from eachgroup of four in the methane assemblage, and then adjusting sothat with the same number of cavities each cavity among the carboSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2325spheres shall be as closely packed as possible, although nowcontaining but three hydrogen spheres instead of four.Suchan operation corresponds with the removal of the iodine atomfrom methyl iodide; the observed fact that in this reaction, asin all similar ones, the condensation of two hydrocarbon radiclesyields one molecule, finds expression in the way in which theassemblage undergoes contraction during the adjustment necessaryfor closing up the produced gaps. The fact that the methyl iodideassemblage, which has the same marshalling as that of methane,yields ethane on treatment with sodium, can be represented asfollows. In the methane assemblage, the carbon spheres are pre-vented from making intimate contact with one another by thepresence of hydrogen spheres packed around them, but when thenumber of the latter is reduced by each group of four becoming agroup of three, the carbon spheres necessarily draw nearer together ;it is conceivable that equilibrium, represented by close-packing,requires them to come into closer contact, and to press on eachother two by two, and that the intimate relationship thus establishedbetween the individuals of a pair corresponds with the linkingbetween the two methyl carbon atoms in the ethane molecule.Itwill be shown in connexion with the assemblage described belowthat the condensation of the assemblage following elimination ofhydrogen spheres and the adjustment which restores closepacking,lead to close contact of the kind referred to between carbon spheres;such contact is thus representative of the formation of a linkbetween carbon atoms such it9 that present in the ethane molecule.The production of the ethane assemblage from that of methanemay also be regarded as resulting from the replacement of one-fourth of the hydrogen spheres, each by one carbon sphere, when,in accordance with the second geometrical property of close-packedassemblages, the introduction of three hydrogen spheres with eachnew carbon sphere suffices for the preservation of close-packing.The alternative ways in which the paraffins may be regarded, such,for instance, as the possibility of considering propane as dimethyl-methane and as ethylmethane, also find expression in the geometricalmode of regarding these substances now advanced.The mmtgeneral method of formulating the normal parafiirs consist8 inassigning to them the constitution H*[CH,],.H, in which an openchain of n-carbon atoms forms the backbone of the molecule, andis isolated from other similar chains in front and rear by theaddition of a hydrogen atom to each of the end methylene groups.For the present purpose it will therefore be convenient to derivefirst an assemblage of the empirical composition CH2, correspondingwith the radicle methylene; it will then be shown how this assem2326 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALblage, composed of strings of methylene groups the carbon spheresof which are in close contact throughout the length of the string,is related to that of methane, and in what manner hydrogen spheresFIG.10.can be homogeneously intercalated so as t o divide the methylenestrings of indefinite length into definite molecular groups torepresent any individual normal p a r f i .FIG.11.The general methylene msemblage may be constructed in thefollowing manner. Space IS divided into endless hexagond prisms,each of which is divided into identical hexagonal cells by describinSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC, 2327a series of parallel planes perpendicular t o the prism axes at adistance apart equal to the smaller diameter of the prisms. I neach prismatic cell thus obtained is inscribed a sphere; the diameterof the latter will be the smaller diameter, and also the height, ofthe hexagonal cell. In t,he system produced, each cell corner marksthe centre of a cavity between adjoining spheres, and about eachmeeting point of cell corners a small sphereis now described of such diameter as justto touch the six surrounding large spheres.The resulting system is shown in plan inFig.10, and in elevation in Fig. 11,and possesses a general arrangementwhich may be visualised by the perspec-tive view of a fragment shown in .Fig. 12.Each small sphere of the assemblage, inaddition to making contact with sixlarge spheres, is nearly in contact with three other small spheres,and each large sphere is in contact with twelve small spheres andeight large ones. If t,he large spheres represent carbon, and thesmaller ones hydrogen atoms, the assemblage has the empiricalcomposition CH,; since, however, the volume of the smaller spheresis appreciably less than one-fourth that of the larger, the valencyFIG.12.FIG. 13.relation of the volumes requires the smaller to increase until thevolumes of small and large spheres, with the addition of theappropriate proportions of interstitial space, are in the ratio of 1 : 4.This expansion of the small spheres necessarily forces the largerspheres apart, and for this to occur in such a manner that themodified system possesses maximum closeness of packing, it musttake place so as to break as few of the contacts as possible in 2328 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALsymmetrical manner. The most symmetrical expansion of thekind which can occur is one which breaks all the contacts betweenlarge spheres and converts the assemblage of Figs.10 and 11 intothat represented in Figs. 13 and 14; the smaller number of contactsin the modified system is indicative of looseness of packing, andin order to reproduce close-packing as many of the original contactsits possible must be reestablished in a symmetrical manner.A consideration of the assemblage of Figs. 13 and 14 in con-nexion with the cubic disposition of large spheres shown in Fig. 4,from which the methane assemblage was derived, shows that t4heplane arrangement of the large spheres in their layers, shown bythe continuous line circles of Fig. 14, is approximately that obtain-ing in the layers of the assemblage of Fig. 4, which are parallel t oFIG. 14.the plane the trace of which is the diagonal line C in Fig. 15, asshown by the continuous line circles of Fig.16. Whilst, powever,in Figs. 15 and 16 each cavity between the large spheres is destinedand is sufficient for the accommodation of a tetrahedral group offour small spheres, the corresponding space in Figs. 13 and 14 hasbeen reduced so that it can accommodate but two small spheres;this has been effected by somewhat increasing the distance betweenthe large sphere centres in the direction of the diagonal C inFig. 15, and considerably diminishing the distance between thelayers of sphere centres in the direction perpendicular thereto.Each cavity which suffices to contain four small spheres, such as isenclosed by the eight spheres, four, p, q, r, and s, of one plane ofFig. 15, and four, t, u, v, and w, of the plane immediately below, aSTRUCTURE AND THE CHEMICAT, COMPOSITION, ETC.2329shown in Figs. 15 and 16, has by the process just described beenconverted into two cavities, namely, one enclosed by the correspond-FIG. 15.ing spheres, p, r, s, t, v, and w, of Figs. 13 and 14, the other by thespheres, q, r, s, u, v, and w. The two small cavities thus derivedFIG. 16.from the original large one each suffices for the accommodation ofone small sphere; these are marked a and b in Figs. 13 and 14.VOL. XCVII. 7 2330 BARLOW AND POPE : THE RELATION BETWEEN THE CRYGTALThe process by which the present assemblage can be derived fromthat, of methane, and also the converse, by which t'he former canbe converted into the latter, are applications of the secmdgeometrical property of close-packed homogeneous assemblages.It remains to indicate the manner in which close-packing can beestablished in the assemblage of Figs. 13 and 14, that is to say, theway in which the assemblage can be caused to occupy the minimumspace as the result of an adjustment which does not involve re-marshalling.The requisite deformation will be understood by con-sidering its effects on the system; these are indicated in Fig. 17,which represents one double layer of the two kinds of spheres, andin Figs. 18 and 19, which are projections of the altered assemblageFIG. 17.on two planes at right angles to one another. For the sake ofclearness, the hydrogen spheres are omitted from Fig. 18.The symmetrical adjustment which increases the closeness of thepacking brings the members of the rows of carbon spheres shownin Fig. 13 alternately into contact and further apart, as indicatedin Figs.17 and 18; thus a carbon sphere, such as p, makes contactonly with m and n, and draws away from r and s. The sequenceof making contact and moving further apart alternates in con-secutive layers of the form shown in Fig. 17, so that these layersnow have two distinct projections on the same area of Fig. 18;the latter diagram thus shows two alternating sets of carbon spheres,those indicated in continuous lines, and those in dotted circles, inplace of the one set shown in Fig. 13. This alternation results inthe formation, in each of the planes projected on Fig. 18, of zigzaSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2331strings of carbon spheres in contact and of indefinite length, thezigzag strings in one plane of the assemblage being located fromthe positions of others in the same plane or of those in the nextneighbouring planes by some simple symmetrical operation sucli asthat about a centre of symmetry; the zigzag strings in one planedo not lie immediately beneath or above those in the next plane.The assemblage of Figs. 17, 18, and 19 represents the generalmethylene assemblage, and is to be regarded as an arrangementhaving the empirical composition CH,, which constitutes tlie open-chain portion of a normal paraffin. By dividing the zigzag stringsinto fragments of suitable length by the introduction of pairs ofhydrogen spheres at appropriate intervals, it may be converted, asis shown below, into an assemblage of molecular aggregates repre-FIG.18.sentative of any particular normal paraffin. The existence of thiscorrespondence between the feature of close-packed assemblages justdescribed and the observed fact that, in the normal paraffins, thechains of methylene radicles connecting the terminal methyl groupsexhibit behaviour which warrants the representation of the normalparaffins by the general formula, CH,*[CH,],*CH,, is worthy of note.It has been shown in previous papers that the configurationsassignable, in accordance with the crystallographic evidence andwith the theory of homogeneous close-packing, to numerous organicsubstances is in entire accord with some features of the chemicalbehaviour of such compounds.Before proceeding to employ theconfiguration arrived at for the general methylem chain, *[UH2In*in the production of assemblages representing the normal paraffins7 N 2332 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALfor comparison with the chemical facts and crystallographic evidence,it is therefore desirable to consider stereochemical features of thechain, *[CH,],*, as now presented. Any such continuous chainseparated from the whole msembhge presents the plan and elevationFru. 19.shown in Figs. 20 and 21 ; a rough perspective view of a fragmentof the indefinitely prolonged chain is given in Fig. 22. It will beseen that each carbon sphere is directly attached to two other carbonFIG.20.spheres and to two hydrogen spheres, and that the plane containingthe centres of the three carbon spheres is perpendicular to theplane drawn through the centres of the two hydrogen spheres andthat of the carbon sphere which they touch. Further, it wiIl bBTRUCTURE AKD THE CHEMICAL COMPOSITION, ETC. 2338seen that by joining the four points of contact made on each carbonsphere, two by hydrogen and two by carbon spheres, a tetrahedronresults. Since these are the essential features of the environmentof any carbon atom of the chain in a normal paraffin, ils summarisedby the theory of va.n’t Hoff and Le Bel, it follows that the con-figuration for the chain deduced above is in accordance with thechemical facts.In this connexion, it is interesting to recall theinterpretation usually put on the important fact of the persistenceof the tetrahedral arrangement of links from term to term of theseries of assemblages representing the normal paraffins. AdoptingFIG 22.the method employed by van’t Hoff and Le Bel, the configuration ofa string of methylene complexes which forms the backbone of anormal paraffin moIecule is derived by first substituting carbonatoms for two of the tetrahedrally disposed hydrogen atoms of amethane molecule, preserving the tetrahedral disposition of thelinks, and then attaching two hydrogen atoms to each added carbo2334 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALatom in such a way that the two outer methylene complexes thusformed are identical with the central one and identically related toit, while having the opposite orientation.The central portion,-CH,*CH2*CH,*, of the propane molecule is thus arrived at.Arrangements proper for the representation of succeeding termsof the homologous series of paraffins are derived by repetitions of thesame process.The form of a group of methylene complexes reached in this wayis quite definite and is that shown in Fig. 22; as the precedingargument has established, a number of the groups representing thesame term of the series can be packed closely together so that thepassage to closest-packed equilibrium involves but a quite trivialadjustment. When additional hydrogen spheres are inserted appro-priately to complete the representation of a given paraffin, anassemblage results, as will be shown immediately, which displaysthe geometrical and dimensional properties appropriate to the crystalof the substance concerned.It is easy to demonstrate that the persistence of the tetrahedraltype of arrangement is a geometrical consequence of substitutioneffected in accordance with the second geometrical property. Forin carrying out such a substitution in a, methane assemblage, theadded carbon spheres are deposited in the hollows on the faces ofthe layers of the assemblage left vacant by the removal of hydrogenspheres, and consequently the incoming large spheres occupy prac-tically the same situations with respect to the unsubstituted portionsrof the assemblage as were previously occupied by outgoing smallspheres.Consequently, since the situations of the paraffin spheresgive a tetrahedral arrangement of the contacts within a moleculargroup, this tetrahedral disposition of the contacts still obtains afterthe substitution. It is not suggested that the tetrahedral arrange-ment of the contacts will remain precisely regular.The Ethane Assemblage.The unit, shown in Fig. 22, of the general methylene assemblageof Figs. 17, 18, and 19 possesses the constitution of an indefinitelylong string of attached methyIene groups,- - -CH2*CH2*CH2*CH2- - -,and is represented by the graphic formula:H H H 13 II Er H H - -c.(-J.c.c.c.(-J.c.c- -H H H H H H I3 HThe comparison which has been made between the generalmethylene assembla-ge and the methane assemblage sliows that ifextra, pairs of hydrogen spheres are introduced between succeedinSTRUCTURE AND THE CHEMiCAL COMPOSITION, ETC.2335carbon spheres, the resulting assemblage assumes the compositionand constitution of methane, thus :H H H H H HHCH HCH HCH HCH BCH HCH.H H H H H HIf, however, such pairs of hydrogen spheres are intercalated, noteverywhere between succeeding carbon spheres, but intermittentlyat points homogeneously selected, the resulting assemblage shouldrepresent a normal paraffin homologous with methane. On intro-ducing pairs of hydrogen spheres symmetrically at half the pointsindicated, the assemblage representing ethane should be produced,thus :H H H H H H H H HITHC-CH HC*CH HC*CH HC-CH HC*C€I.H H H H H H HE3 H HIt is desirable to confirm this deduction by an examination of theethane assemblage, thus derived, in the light of the principalcrystallographic evidence available; this is found in the dataobtained by Gossner for the hexahalogen derivatives of ethane andfor pentabromoethane (Trans., 1906, 89, 1682).I n the tabulateddata for these substances it is convenient t o double the ratio ofc / b , and to state the equivalence parameters and axial ratios as inthe appended table; the valency volume, Iy=14, is regarded asthe molecular space unit, so that the linear unit employed for theequivalence parameters is the edge of a cube of unit valency volume.The closeness of the packing of the spheres is taken to be the sameas that of the closest-packed assemblage of equal spheres:n : b : c.B. x. : y : 2.CCl,'CCl, ............... 0.5677 : 1 : 0.6320 90" 1.9255 : 3.3917 : 2.1435CHI,Cl'CCI, ........ 0 5612 : 1 : 0.6342 ,, 1.9086 : 3 4009 : 2.1520CBtCI,'CBrCl, ...... 0'5646 : 1 : 0'6384 ,, 1.9120 : 3.3567 : 2.1620CHr,*CBr, ............ 0.5639 : 1 : 0 6284 1.9205 : 3'4058 : 2.1403CHBr,*CBr, ........ 0'5650 : 1 : 0'6286 91bi9' 1.9282 : 3'4126 : 2.12811.9166 : 3.3963 : 2'1494 Mean for fir& four substances :In calculating the mean equivalence parameters, the four ortho-rhombic substances only .have been considered, the monosymmetricpentabromoethane being excluded from the calculation.It has now to be considered how the general methylene assemblageof Figs.17, 18, and 19 can be converted into a close-packed assem-blage of the dimensions represented by the above mean equivalenceparameters, z: y : z=1'917: 3,396: 2.149, by the intercalation ofpairs of hydrogen spheres in the manner already indicated. Thediameter of a univalent sphere is obtained in terms of the linearunit from the consideration that it is the face-diagonal of the cubeoutlined by joining the obtuse solid angles of the unit dodecahedro2336 BARLOW AND POPE : THE RELATION BEI'WEEN THE CRYSTALof a closest-packed assemblage of these spheres (Trans., 1907, 91,1181). Thus, if a be the diameter in question, a / .\/Z is the edge ofthe cube inscribed in the unit dodecahedron; the content of thiscube is a3/ZJ2, and that of the dodecahedron is equal to a 3 1 d2,which is taken as unity. Consequently, a=2h =1*1225, and sincethe volume of a quadrivalent.sphere is four times that of a univalentone, the diameter of the former is 23 x 2: = 2." = 1 *781@.The sphere projections in the general metliylene assemblage ofFigs. 17, 18, and 19 are drawn to the scale thus indicated, and thedimensions indicated in these figures are, two of them, the values,x=1*917 and y=3*396, of the mean equivalence parameters in thetable last given. On introducing between each pair of layers ofthe general methylene assemblage extra hydrogen spheres equal innumber to the carbon spheres already present, the preservation ofPIG. 23a.close-packing demands that the one pair shall shift upon the nextpair, so that the projection of the two pairs now consists of foursuperposed sections, as depicted in Figs, 23, a and b .I n these diagrams, which, taken together, give a projection of theethane assemblage, some of the intercalated hydrogen spheres aremarked a; the dimensions, x = 1.917 and y = 3.396, are shown in theplane of the section.The packing is about as close as in the methaneassemblage described above, and since the closeness of the packingis thus adhered to and the composition is that corresponding withethane, the translation perpendicular to the plane of the sectionwill necessarily have the corresponding value of z = 2.149. Sincethe valency volume of the molecular unit is 14, and that, of theterminal hydrogen spheres is 2, the dimension 2: of the methyleneassemblage, as shown in Figs.17 and 18, is six-sevenths of the z valuSTRUCTUKE AND THE CHEMICAL COMPOSITION, ETC. 2331just stated, and therefore equals 1.842; this is the value of a used inthese diagrams. It is concluded from the above that the assemblagedepicted in Fig. 23 is related to the general methylene assemblagein the appropriate manner, and has the dimensions indicated forethane by the crystallographic data; the crystalline symmetry ofthe assemblage, when all the smaller spheres are identical in kind,is the orthorhombic symmetry exhibited by the liex&hdogenderivatives of ethane named in the table. It is, however, obviousthat differences in kind occurring among the smaller spheres mighthave the effect of reducing the symmetry of the assemblage in themanner indicated by the existence of the monosymmetric penta-bromoethane.Lehmann has shown (MoZel~uZal.-F~ysil., 1888, 1, 178) that hexa-FIG.23b.chloroethane, C,C16, crystallises in an anorthic and a cubic formas well as in the orthorhombic form dealt with above; no measure-ments are available for the former modification, but it is instructiveto deduce the assemblage representing the cubic form of the sub-stance. In view of the close relationship which must exist betweenthe orthorhombic and the cubic modifications of hexachloroethaue,it is convenient to derive tlhe assemblage for the latter from thatof the former. The orthorhombic assemblage may, for purelycrystallographic purposes only, be regarded as built up from aunit of the form shown in Fig.24, a, b , c, and d, and consisting oftwo carbon spheres in contact having a circlet of six chlorine spheresplaced round the neck produced between the two large spheres;the volumes of the two kinds of spheres, namely, 4 : 1, are suchthat when all the six small spheres touch the two larger ones, theyvery approximately form a continuous ring of small spheres i2338 BARLOW AND POPE : THE BELATION BETWEEN THE CRYSTALcontact as shown in the diagrams. A geometrical unit of this kindis marked ABcdefgh in Fig. 23u, and presents in that diagram theC.FIG. 24.b.d.aspect depicted in Figs. 25 a and b ; it can be used in the mannerdescribed below for the construction of the assemblage representingthe cubic modification of hexachloroethane.FIG.25.a. b.The geometrical units referred to and figured occupy the valencyvolume, W=14, and can be fitted together in cubic symmetry sS'l'HUCTURE BND THE CHEMICAL COMPOSITION, ETC. 2339that their centre points lie at the centres of the cube cells of acubic partitioning of space provided that the cube cells have thevolume 14; the length of tihe cell edge should therefore be 3d14,t8he scale previously used being adopted. The units are fitted intoa system of non-intersecting trigonal axes of the kind alreadydescribed (p. 2317), and in the following manner. In one cubecell the trigonal axis of which has the direction indicated by u(Fig. 5), place a geometrical unit group so that its centre is at thecentre of the cube cell, and so that the centres of its two largespheres lie on the single trigonal axis of the cell; whatever theposition of the small spheres, it is evident that their centres lie ona circle the centre of which is the point of contact of the two largespheres, and the plane of which is perpendicular to the trigonalaxis of the unit.This circle is projected on one of the three facedirections of the cube cells as an ellipse, as indicated in Fig. 25b.Geometrical units are now fitted in similar manner into the othercube cells of the system, due regard being paid to the preservationof the respective trigonal axes, a, b, c, and d, of the different cellsof the partitioning.A single layer of the resulting system of cells with their contentsis depicted in Fig.26 as a projection on a cube plane; the projectionsof the trigonal axes are shown a,s continuous straight lines, andare lettered a, b, c, and d, in accordance with the conventionpreviously adopted (Trans., 1907, 91, 1183). Digonal axes ofrotation pass through the assemblage' perpendicular to the plane ofprojection at the points S, T, U, and V.The precise position of the small spheres in the assemblage isdeduced by reference to the digmal axes of symmetry. Thus thegeometrical unit is so placed in the cube cell of the partitioningthat the distance of the centre of one of its small spheres from adigonal axis is equal to the radius of the small sphere; thiscondition is practically fulfilled if the position of the circlet ofsmall spheres is such that the centre of one of them lies at thehighest point of the circular locus, the projection of this centretherefore falling a t one extremity of the minor axis of the ellipsein which the circular locus is projected on the plane of a cube face.When one geometrical unit has been placed in position in themanner indicated, others can be similarly located with their centresa t the remaining cell centres by carrying out the coincidencemovements and operations with respect to the axes of the firstselected cell. The type of symmetry is that numbered Za, inBarlow's list (Zeitsch.Kryst. Min., 1894, 23, 44).It is evident from Fig. 36 that the spheres of the single layerof complexes fit closely together in the marshalling indicated, and2340 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALas the assemblage can be regarded as made up of such layers parallelto either of the three directions of the cube faces, it follows thatthe georretrical units employed can be fitted together in space inthe manner indicated, and that the packing is very close.The geometrical unit which has been used in building up theorthorhombic and the cubic crystalline assemblage of hexachloro-ethane is, as before mentioned, merely used for constructionalFIG.26.purposes, and is not to be regarded as possessing the configurationof the chemical unit or molecule. The possession of a larger massof crystallographic data than is at present available should enablethe configuration of the chemical molecule to be determined by aprocess of elimination.The various polymorphous forms of thedifferent halogen derivatives of ethane must all consist of packedarrangements of units having the configuration of the ethanemolecule; further, the latter must be derivable from the generaSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2341inethylene assemblage by the sy’inmetrical intercalation of spheresof unit valency volume in this assemblage, as already described.These conditions are fulfilled, not only by the geometrical unit usedabove, but also by groups of the composition C,CI, possessing aconfiguration such t,hat the eight component spheres are centredat the apices of two tetrahedra so placed that an apex of the oneis directed towards an apex of the other.The two kinds of unitof the structure thus distinguished possess the configuration of theethane molecule as it has been deduced from the principles laiddown by van’t Hoff and Le Bel; rough perspective views of thecliemicnl nnit or molecule thus derived are given in Figs. 27 a and h .FIG. 27.na. b.It will be seen that the one may be derived from the other byrotating onehalf of the unit through 180° with respect to theother half. The fact that these two configurations of unit, closelyrelated by the mode in which one is convertible into the other, canbe traced in the assemblage as depicted in Fig. 26, is of interest inconnexion with van’t Hoff’s doctrine of the free rotation of a singlyhound carbon atom.An Alternative General Met?&iylene Assemblage.A simple method has been given above (p.2333) for derivingan aasemblage which can be geometrically partitioned into endlessstrings of the general form n(CH,), and it has been shown howthe assemblages representative of the normal paraffins can be derivedfrom this general methylene assemblage by the intercalation ofhydrogen spheres. Examination shows, however, that by modifyingthe assemblage referred to by means of a particular kind ofdistortion, an alternative series of assemblages is obtained , in whichthe arrangement of the carbon and hydrogen spheres which formthe methylene fragments is very nearly the same as before: thi2342 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALarrangement, like the first, is related to a number of crystallographicfacts. The new kind of arrangement can be derived from thefirst by an adjustment or deformation which leaves each sphere wit,liFrc.28.practically the same surroundings but which changes the generalsymmetry: the nature of the adjustment is a-s follows.The large spheres of one layer (Fig. 28) in the unadjusted methyleheassemblage of Fig. 14, when pressed together in the direction whichFIG. 39.U b.is horizontal in the diagram, fall into a square arrangement;simultaneously, the smaller spheres, by movement on each otherand on the large spheres with which they are in contact, are ableto accommodate themselves to the altered form of the layer, anSTRUCTURE AND THE CHEMICAT. COMPOSITTON, ETC.2343can pack very closely into the hollows remaining after the changeis made. The section of the assemblage shown in Fig. 28 thusbecomes that shown in Fig. 29 a and 6; the modified layer consistsof a plane of the larger spheres in square arrangement with thesmaller spheres sunk in the hollows on both of its faces; the smallspheres touch each other in the plane drawn through the centresof the large spheres, as shown in Fig. 29b. Layers produced in thismanner can be fitted closely together in such a way that theresulting assemblage is practically identical with that previouslyreached by compounding the layers in their other shape. I n otherwords, the layers depicted in Fig. 29 are obtained from the generalmethylene assemblage of Fig.14 if, instead of making the separationinto layers parallel t o the plane of Fig. 14, it is made parallel tothe plane of projection of thesame assemblage shown inFig. 30. The plane of projec-tion of Fig. 30 is at rightangles to those of both Figs. 13and 14; thus, in Fig. 31a, inwhich the arrangement isidentical with that in Fig. 13,a plane perpendicular to theplane of the diagram, drawnthrough AB, gives the projec-tion shown in Fig. 14, whilsta plane drawn through CD,also perpendicular to the planeof Fig. 31a, gives the sectiondepicted in Fig. 31b.FIG. 30.The conversion of the general methylene assemblage depicted inFig. 30 into that representing a normal paraffin is, as before, effectedby intercalating hydrogen spheres, twice as numerous as the carbonspheres in a single layer, between consecutive layers of carbonspheres appropriately selected, the planes of these layers beingparallel to the plane of projection of Fig.30. It is seen fromFig. 29a that the principal hollows, which are of the kind markedA, in one of the surfaces of a layer are twice as numerous as arethe carbon spheres of the layer; if therefore two such layers areappropriately placed together, a layer of hydrogen spheres twiceas numerous as the carbon spheres of a layer can be closely fittedbetween them, each sphere occupying a principal hollow, such aa A,in both the opposing faces. The combination of two layers of thecomposition CH2 with the layer of hydrogen spheres thus fittedin between them, is shown projected in Fig.32: the small sphere2344 EARLOW AND POPE : THE RELATTON RETWEEN THE CRYSTALof the intercalated layer are indicated-by double circles. In theassemblage representing a normal paraffin formed in this manner thePro. 31a.FIG. 31b.hydrogen spheres added to aterminal layer of the formCH,, and allotted to this layer,occupy the same positions inthe face of the layer as theywould i f an additional CH,layer, of which they formedpart, were added; this can beseen on inspection of the pro-jection of a stratum of aparaffin assemblage of theform under consideration. Thestratum represented in Figs.31 a and h is that appropriateto normal butane,CH,- CH2*C H,* C H, ;corresponding with the fourmethylene radicles, CH,, thereare present four layers of largespheres in each stratum, asshown in Fig.31a.The centres of the terminalsmall spheres which have beenintroduced lie on two similarsets of digonal axes of theassemblage having two direc-tions perpendicular to oneanother as indicated by thediagonal broken lines of Fig.32; the identity of these di-gonal axes in the two directionsinvolves the presence of screwtetragonal axes perpendicularto the planes containing thedigonal axes. Thus, the assem-blage of a, normal p a r d n inthe modified form now de-scribed can present tetragonalsymmetry ; the orientations ofthe succeeding strata, each ofwhich is composed of a certain number of layers of the compositionCH, with the terminal hydrogen spheres added, will then differ bSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.234590°. As remarked above, a section of a single stratum present ina, butane assemblage is represented in Fig. 31.That the marshalling of the assemblage of a normal paraffin,when of this altered form, is compatible with very close packing,is evidenced as before by the approach to a maximum of the numberof contacts or close proximities round each sphere. Thus, each endcarbon sphere of a chain is in contact with, or in close proximity to,six large spheres and fifteen small ones, together twenty-one, andeach of the other large spheres is similarly environed by eight largeand twelve small spheres, together twenty. Each terminal smallsphere is environed by four large and four small spheres, and nextto the terminal ones occur other small spheres immediatelysurrounded by five large and five small spheres: in the interiorof the assemblage each small sphere is environed by six large andthree small spheres. As before, the carbon spheres of a moleculecontaining several atoms forma zigzag string; the angles ofthe zigzag are, however, muchmore obtuse in the form ofassemblage now under con-sideration.The relation be-tween the latter, which may becalled the tetragonal assem-blage, and the orthorhonibicform of assemblage previouslydescribed, is indicated bystating that whilst the mar-shalling of the methylene por-tion is the same in both, theone is obtainable from theother by a general distortionFIG.32.which alters the angles of the zigzag formed by the chain of carbonspheres, but does not appreciably alter the environment of thedifferent spheres or the closeness of the packing; the molecular unitsare of a slightly altered form, although they retain much the samegeneral configuration. I n view of the indications obtained of theexistence of alternative modes of partitioning, which do not giverise to observable tautomerism, in connexion with benzene (Trans.,1906, 89, 1696), and of such alternative modes which furnish amechanism for the occurrence of tautomeric and isomeric change,it is very possible that a paraffin derivative which occurs in oneform of assemblage throughout one range of temperature wouldundergo conversion into the alternative form on entering a differentrange of conditions.VOL.XCVII. 7 2346 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALCrystalline Form of Iialogen Derivatives of IIomologues of Ethane.It will be convenient now to discuss the rather sparse crystallegraphic data available for the halogen derivatives of the homologuesof ethane, and to show that these data are very closely and verysimply related t o the two forms of assemblage described above.The whole of the available goniometric data are dealt with underthis heading.@By y-Tetrabromobutane, CH,*CBr2*CBr2*CH,, is dimorphous, andexists as a tetragonal and an orthorhombic modification, whichhave been measured by Fedoroff (J. p. Chem., 1890, [ii], 42, 145).The tetragonal form has the axial ratio a : c =1: 1-28; on statingthis in the alternative tetragonal form of a : c = d 2 : 1.28, andmultiplying the value of cla by four, the number of carbon atomsin the open chain, the ratio becomes, when stated in the moreconvenient orthorhombic form :a : b : c=1'414 : 1.414 : 5.120.The valency volume of this butane derivative is W = 2 6 , and theequivalence parameters are thence calculated as :x : y : ~ = 1 ' 9 2 9 : 1.929 : 6.985.Since, in the tetragonal type of assemblage, the strings of carbonspheres which form the backbone of the molecules all have the samemean direction, symmetry would indicate that this is the direction ofthe axis c in the tetragonal crystal form now under discussion.The longer direction of the molecule having thus the direction ofthe parameter z, the dimensions of the fragment, CH,, in the crystalstructure should be the above x and y and the fraction, 6/26, ofthe above length, z .The equivalence parameters of the fragment,CH,, of the normal butane assemblage are thus calculated fromthe crystal form of the tetragonal modification of PBy y-tetrabromo-butane asx : 9 : ~ = 1 * 9 2 9 : 1'929 : 1.612.These values should represent translations in the tetragonal formof the general methylene assemblage; that they do represent suchtranslations is shown by the manner in which they adapt themselvesto the description of Fig. 31, in which they are marked. Theorhhorhombic modification of the substance is dealt with later(p. 2347).The isomeric aSy6-t etrabromobut ane,C H,B re CH B r C HB r *CH,B r,is described by La Valle (Ber., 1886, 19, 572) m orthorhombic witha : b : c =0*9776 : 1 : 1.6820, and is thus pseudotetragonal.MultiSTRUCTURE AND THE CHEMICAL COMPOSLTION, ETC. 2347plying the ratio, c / b , by two, and ca-lculating the equivalenceparameters for bhe whole molecule with ST'= 26, and for the fragmentwith W I-: 6 in the same manner as before, the values are obtained as :x : y : :=1'947 : 1'992 : 6.701.x : : :=1'917 : 1'992 : 1.546. ,, W=6.With W = 2 6 .These values are not far removed from those obtained with thetetragonal isomeride ; they suggest a slight spreading of the layersin the present instance as compared with the previous one, and aslight compensatory approximation of succeeding layers in thedirection of the axis c.A stereoisomeride of this substance isconsidered below (p. 2348).The tetrabromohexane of the constitutionCH,Br*CHBr*CH,*CH2*CHBr .CH,Bris described by Negri (Ber., 1889, 22, 2498) as orthorhombic witha : b : c=O.3641: 1 : 0.3788, and is also pseudotetragonal. Onmultiplying the length, 6 , by two, interchanging b and c, andcalculating just as before the equivalence parameters for the wholemolecule, with TV=38, and for the fragment, CH,, with W=6,the following values are obtained :x ; y : 2=1*880 : 1.956 : 10.329. With TV=38.x : y : ~=1'88O : 1.956 : 1'631. ,, W= 6.These values for the methylene fragment approximate closelyto those derived from the two previous cases.The three halogen derivatives just above discussed thus presentthe tetragonal type of assemblage; the following appear to exhibitthe alternative orthorhombic type first described, of which thehalogen derivatives of ethane previously referred to afford examples.As already noted, j?By y-tetrabromobutane is dimorphous, andfrom Fedoroff's data for the orthorhombic modificakion Jaeger hascalculated (Trans., 1908, 93, 521) the axial ratios as a : b : c =1.8671: 1 : 3-478.On multiplying the length b by four, thenumber of carbon atoms in the chain, interchanging b and c, andcalculating the equivalence parameters for the whole molecule, withTV=26, and for the methylene fragment, CH,, with W=6, thefollowing values result. :x : IJ : x=1*868 : 3.479 : 4.000.x : 2/ : z=1'868 : 3.479 : 0.923.With W=26.,, w== 6.From the mean values of the equivalence parameters for thehalogen derivatives of ethane, namely, x : y : z = 1.967 : 3.396 : 2.149,with the valency volume, W=14 (p. 2335), we obtain for themethylene fragment, CH,, with W = 6 , the values x: y: z =1.917 : 3.396 : 0.921; the value of z here is half that of the z ofFigs. 17 and 18.This set of values approximates closely tothat calculated from the data for the orthorhombic Wyy-tetra-7 0 2348 BARLOW AND POPE: THE RELATION BETWEEN THE CRYSTALbromobutane, and indicates that the latter substance affects a formof assemblage identical in type with the orthorhombic ethanederivatives.An aP y 8-tet r ab r omobutane, CH,B r CHB r CHB r CHzB r, st er e eisomeric with that discussed above, has been described byPanebianco (Ber., 1888, 21, 1432) as crystallising in the mono-symmetric system with a : b : c = 2.6348 : 1 : 2.3335, p =80°55/.Ontransposing these axial ratios so that (101) becomes {loo}, and(101) becomes {OOl), the axial ratios are obtained in the forma : b : c=1'6198 : 1 : 1.8678, /3=8Z058/30//; in these values a isdoubled and taken as b , c is taken as u, and b is multiplied by fourand taken as c. The axial ratios are thus obtained in the forma : b : c = 1.8978 : 3-2396 : 4.000, The equivalenceparameters for the whole molecule, with W =26, and for the frag-ment, CH,, with W=6, are now calculated as before; the valuesobtained are :a = 82O58/30/'.a: : y : z=1'938 : 3.316 : 4.085.With lY=26.x : y : ~=1'938 : 3'316 : 0'943. ,, ll'= 6 .The latter set of values also agrees well with that derived fromthe halogen derivatives of ethane, namely, with x: y: z =1.917 : 3.396 : 0.921.The Secondary and Tertiary Paraffins.The discussion of the configurations of the normal paraffins inthe previous pages has revealed a singularly close correspondencebetween the customary method of representing the constitution ofsuch substances and the conception of their configurations derivedfrom the geometrical application of close-packing to assemblages ofspheres of two volumes in the ratio of 4 : 1. It has yet to be shownthat the correspondence extends to the secondary and tertiaryhydrocarbons of the same series.Tetramet h ylmet hane (PB-Dimet hylpropne), C(CH,),.The most obvious method of arriving at the assemblage represent-ing tetramethylmethane consists in replacing each hydrogen spherein the methane assemblage by the methyl radicle, CH,, in accordancewith the second geometrical property; the discovery of the precisearrangement of the assemblage is, however, attended with muchdifficulty if this mode of procedure is adopted.Another method,which is more readily traceable, depends on the application of thefirst geometrical property to the methane assemblage, and may bethus described.It has been pointed out that the four hydrogen spheres associatedto form a close group in a methane assemblage belong to fouSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2349different molecular groups, CH, ; if t,herefore a carbon sphere, whichis quadrivalent, be substituted for .a single close group of fourhydrogen spheres, it will belong to, and will connect, four partialgroups or radicles, CH,, and thus give a composite group of therequired composition, C( CH,),. Consequently, if throughout themethane assemblage every fourth close group of the composition H,,selected symmetrically, is removed, and a carbon sphere substituted,this being done in such a manner as to make the relation of theunits so obtained to the assemblage as a whole identical, such anassemblage will furnish a possible solution. There are two waysof accomplishing this in a highly symmetrical manner, eitherof which would appear to be in harmony with the ascertainedfacts.When the structure of the methane assemblage was under con-sideration, it was pointed out that the shape and orientation of thegroups, H4, influence the form of the skeleton framework composedof the carbon spheres, the reason of this being that the arrangementaffected by these spheres must be such as gives the closest-packingof the groups in the cavities containing them; the substitution ofsingle carbon spheres for some of the H, groups will, on the sameprinciple, involve some sIight modification of the skeleton frame-work of carbon spheres.The precise nature of this change isdifficult to trace, especially in the absence of crystallographic data;for diagrammatic purposes it is therefore better, in each of thetwo solutions of the problem, to employ the simple arrangement ofthe carbon spheres in ax high it symmetry as the marshalling whichthey present is capabIe of, without attempting to depict the exactequilibrium conditions ultimately attained.The simpler of the two arrangements possible for the substitutedcarbon spheres has cubic symmetry. Thus, let the points of acertain cubic space-lattice indicate the centres of the carbon spheresof a methane assemblage; the centres of the cubes outlined by thesystem form a second similar space-lattice and mark the positionsof the tetrahedral hydrogen groups.One-fourth of the groups canbe selected for removal and substitution by additional carbonspheres in such a way that their arrangement is that of the un-hatched cubes indicated in Fig.33 a and 5 , which gives the twoprojections of the two sets of alternate layers. The alternativearrangement is a simple tetragonal one, and is shown in Fig. 34;this diagram is identical with Fig. 4, with the exception that everyfourth cavity, symmetrically selected in tetragonal symmetry, isoccupied by a carbon sphere. The newly introduced carbon spheresare shown as broken line circles, and are arranged contiguously inone of the three axial directions, namely, that perpendicular to th2350 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALplane of the figure; the groups of hydrogen spheres, H,, fill thestrings of cavities marked A, which are not occupied by the addedcarbon spheres. Thus, the complete assemblage, much as in thecase of benzene previously described (Trans., 1906, 89, 1693),consists of continuouscolumns of c a r b o nspheres in contact, theinterstices b e t w e e nwhich are filled withgroups of hydrogenspheres so arranged asto produce close-pack-ing; the columns coii-sist of square groups offour separated by singlecarbon spheres through-out.In both the cubic andthe tetragonal assem-blage described, themost symmetrical way ofpartitioning the systemof carbon spheres intogroups of five is to makethese groups tetrahedralwith the substitutedspheres a t the centres.Thus, in Fig.34, thesphere R can be asso-ciated with P and Q ofthe four above, and withS and T of the fourbelow, the four spheresP, Q, S, and T thus pre-senting a tetrahedralarrangement about thesphere R.The disposi-tion of the carbonspheres in the moleculeof tetramethylmethane as thus derived is identical with thatindicated by ths theory of van’t Hoff and Le Bel. The tlirechydrogen spheres attached to each methyl carbon atom will lie, asin methane, one in each of three out of four tetrahedrally situatedcavities surrounding each methyl carbon sphere ; the hydrogeSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2351spheres will follaw, as closely as possible, the original arrangementprevailing in the methane assemblage.Inspection of Fig. 34 shows that the tetragonal assemblage fortetramethylmethane, like the first described, must approximateclosely to cubic symmetry.The correctness of the mode of arrivingat the arrangement which is here adopted is confirmed by Jaeger’sdetermination of the crystal form of the tetrabromo-derivative ofthe hydrocarbon, namely, C(CH2Br),; this author has shown, mFIG. 34.already indicated, that the substance is pseudo-cubic, being monesymmetric with the axial ratios, a : b : c = 1.0484 : 1 : 0.9472,B=9Oo45’ (Trans., 1908, 93, 520).Trim e t hglme t hane (isoBu t an e), CH (CH,),.It has been seen that the appropriate symmetrical intercalation orexcision of methylene layers, CH,, effected in the case of a givennormal paraffin assemblage produces some other normal paraffinassemblage ; similar operations applied singly or in succession tothe tetramethylmethane assemblage just described are productiveof other assemblages appropriate to secondary or tertiary paraffins.The principle involved in such operations may be stated as follows.A regular layer of spheres, so constituted as to form the unit layerof a, closest-packed assemblage of spheres, for example, a methylenelayer, forms a, constituent of some closestrpacked assemblage.It isthen found (a) that the two parts of this assemblage obtained b2352 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALthe excision of this layer can close up and become closesbpackedwithout any material rearrangement., and ( b ) that if, instead ofremoving this layer, the assemblage is divided so a to expose oneof the faces of the layer, a second similar layer can be fitted onto this face and then the parts fitted up so as to form a closest-packed assemblage in which the added layer is intercalated.The application of this principle depends on the property of anassemblage composed solely of such identical layers that sometranslation brings the contour of the adjoining portion of theassemblage which is fitted against one side of a single layer tocoincidence with the contour of the other side of this layer, coupledwith the fact that close-packing involves a close similarity of contourbetween all the surfaces of different sphere combinations whichdisplay the common property of fitting closely on to the samesurface.For the present purpose, isobutane or trimethylmethane,CH(CH,),, may be regarded as derived by the removal of methylene,CH,, from the tetramethylmethane molecule.The possibility ofperforming this operation symmetrically on the tetramethylmethaneassemblage, whether of the cubic form or of the tetragonal formrepresented in Fig. 34, constitutes a parallel between our methodof formulation and the chemical relationship subsisting between thetwo hydrocarbons. The process is rather simpler as applied to thetetragonal form; this case may be described as follows.One-fifth of the total number of carbon spheres in the tetriLmethylmethane assemblage are symmetrically removed, together withtwice the number of hydrogen spheres, by withdrawing every fourthlayer of the original carbon spheres taken parallel to a planeperpendicular to the diagram through a line DE in Fig. 34, togetherwith the accompanying hydrogen spheres, and closing up thestructure by bringing the exposed surfaces together.As the resultof this operation, the skeleton assemblage depicted in Fig. 35 isobtained; it will be seen that, of the carbon spheres P, Q, S, and T,and the set of four, PI, Ql, S,, and TI, making up the eight carbonspheres which together enclose a substituted carbon sphere, onlyP, PI, Q, Q1, S, and S, survive, and that the new groups form twosets oppositely orientated in the resulting assemblage. In closingup the structure after removal of the methylene layer, a lateralshift is made, such a relative disposition of the opposing boundariesbrought together being selected as brings the columns of carbonspherw at one boundary opposite to the strings of hydrogen spheresin the opposing boundary; this is possible because the central planeof the methylene layer in the original assemblage and the plane ofthe hydrogen spheres which becomes central in the modifieSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2353assemblage are alike capable of functioning as planes of glidingsymmetry. The approximation of the portions fitted together, orthe space gained by the excision, is treated as dependent on thepostulate that the group of four hydrogen spheres occupies thesame space in the assemblage as one carbon sphere; it follows fromthis that the CH, layer occupies three-fourths of the space requiredby a, CH, layer.The method described indicates roughly the relation of theF I G .35.required assemblage to that of t,etramethylinethane, but thecharacter of the marshalling in the arrangement derived is imper-fectly defined; still less is the precise nature of the crystallinesymmetry exhibited. The absence of crystallographic data for thehalogen derivatives of isobutane leaves the aymmetry in doubt, butit is possible to assign to the marshalling of tetramethylmethane avery simple form, from which an equally simple one for trimethyl-methane can be derived.I n the absence of crystal data, much latitude is presented forthe shape taken by a given marshalling, and naturally the mar2354 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALshalling of an assemblage can be most readily investigated whenin its simplest form.Although this form will not, in general, beFIG. 36n.FIG. 36b.FIG. 36c.the closest-packed one, itwill approximate to theclose-packed condition,and will display the pro-perty that every spherewill be in contact with,or in close proximity to,a large number of sur-rounding spheres. Now,the methane assemblage,without changing itsgeneral marshalling, cantake the form depictedin Fig. 36 a and b ; thesimplest shape of themethylene layer, CIA,, asdepicted in Fig. 11, canhere be recognised. Eachlayer of molecules, CH,,consists of the simplemethylene layer withthe additional hydrogenspheres symmetrically dis-posed in the same manneron both sides of it, asshown in the section f ;the manner in which suc-ceeding layers are fittedtogether in this simplemarshalling is indicatedby superposing b on a ofFig.36. It must beclearly understood thatthe assemblage t'hus pre-sented is not in itsclosest-packed form; it isa distortion of the closest-packed assemblage abovedescribed of such anature as to simplify t.he internal symmetry without changingthe marshalling. The methane assemblage, thus regarded,gives a configuration of the important radicle CH,, which iSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2355entirely in harmony with the symmetrical properties expressed bythe graphic formulae of the hydrocarbons. When it is employed asthe root methane assemblage, the marshalling of the compoundunder consideration, and that of other kindred compounds, canbe readily traced, and will be seen to be in accordance with thegraphic formulae.The first step is toderive the correspond-ing simple form ofmarshalling for tetra-methylmethane; t h i scorresponds with thetetragonal type of thecompound above indi-cated, and may beregarded as producedfrom it by a distortion.The process of deriv-ation from the methaneassemblage just de-scribed consists in sub-stihting strings ofcarbon spheres for one-fourth of the strings ofgroups of the composi-tion H,; as a result ofthis change, the arrange-ment shown by super-posing b on a of Fig.36becomes that obtainedby superposing c on aof this figure. Thelayers shown on theplane of the dia.gramare the same as thosefound parallel to aplane drawn throughDE perpendicular tothe plane of Fig.34.FTG. 36d.>ooooq)ooooq\ n n n n dFIG. 36e.FIG. 36f.Tlie marshalling for trimethylmethane is obtained directly fromthat for tetramethylmetha.ne by removing the central methyleneportion from half the unsubstituted methane layers selected sym-metrically and closing up the gaps, using the remnant hydrogenspheres in filling in between ihe parts of the assemblage which haveto be fitted together after the excision. I n the tetramethylmethan2356 BARLOW AND POPE: THE RELATION BETWEEN THE CRYSTALassemblage, layers of the composition CC + CH, (Fig. 36c) alternatewith layers of the composition ZCH, (Fig. 36a); the result of theexcision described is to give a succession of sets of layers,2CH, : CC + CH, : 4H : CC + CH,, etc., as represented roughly bysuperposing a2 c, d, and e of Fig. 36.The corresponding molecular unit is a combination of one carbonsphere from a layer a with the three carbon spheres of one of thetwo adjoining layers together with a due proportion of hydrogenspheres; the units are so constituted as to be all alike.Withregard to the positions of the planes of gliding symmetry mentionedabove, it is to be noted that in the tetramethylmethane assemblagethe gliding plane is the median plane of layer a, and in the trimethyl-methane assemblage it is the median plane of layer a or d ; theseplanes of gliding symmetry can be traced in Figs. 34 and 35respectively. As already intimated, the nature of the adjustmentof thia marshalling which would be productive of the precisecrystalline form remains unidentified owing to the absence ofcrystal data.‘I he geometrical process by means of which the trimethylmethaneassemblage can be converted into that of tetramethylmethane isanalogous to the process of preparing tetramethylmethane by theaction of zinc methyl on ten!.-butyl iodide.Dimethylcthylmethanfe (isopentune), (CH3),CH*CH,*CHI.If, in the derivation of the isobutane assemblage from that oftetramethylmethane, a layer of the general methylene composition,CH,, such as is excised from one side of the layer of tetramethyl-methane complexes, is inserted in the symmetrical position on theother side of the layer, and the requisite shift of one layer onanother made to close up the packing, the assemblage appropriateto isopentane or dimethylethylmethane results.The added layerhas thus t o be inserted on one side of each layer marked DE inFig. 35. The relative situations of the two layers, CH,, thus placedtogether are indicated in Fig. 14; the relation of the compositelayer formed to the remaining portion of the assemblage is shownin Figs. 34 and 35. The marshalling, as before, is represented in itssimplest form.Propane, CH,*CH,*CH,.I f , in addition to the excision of the layers, DE, from the tetra-methylmethane assemblage of Fig. 34 a set of layers, BAAC, parallelto them and symmetrically situated, is similarly removed and theexposed surfaces brought together as before, an assemblage isobtained which has the composition of propane. It is possible soto partition the assemblage thus obtained as to derive moleculaSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2357units of the form already indicated for propane (p. 2334); this ismost readily shown in connexion with the original tetramethyl-methane assemblage of Fig. 34.In the propane unit described in connexion with the normalparaffins, the central carbon sphere makes four tetrahedrallysituated contacts with surrounding spheres, two with carbon and twowith hydrogen spheres, and of the four tetrahedrally situated con-tacts of each end carbon sphere, one is with a carbon and three withhydrogen spheres. Now in the tetramethylmethane assemblagereferred to, each central carbon sphere makes four tetrahedrallysituated contacts with carbon spheres, and when the withdrawal ofparallel strata occurs, two of the four outer carbon spheres and fourhydrogen spheres are removed from each molecular group.And asthe removal of the carbon spheres reveals hollows on the surfacesexposed, formerly occupied by these spheres, which, when the closingup takes place, are occupied by hydrogen spheres projecting fromthe opposing similar surfaces, it i s evident that the central carbonsphere of each group is, after the process, surrounded by fourspheres, two of each kind tetrahedrally arranged. Further, it canbe shown that each end carbon sphere, as in the tetramethylmethaneassemblage, has tetrahedrally situated contacts with a carbonsphere and three hydrogen spheres.Thus, the hydrogen spheresremaining of a methane stratum, from which the central CH, layerhas been removed, are left embedded in the two faces exposed, halfin each; they consequently retain the same positions relatively tothe end carbon spheres of the group found in the stratum to whichthey are attached. The same is true of the hydrogen spherescentrally placed in the stra.tum containing the end carbon spheres.Consequently, each end sphere of a group has the same tetrahedrallyarranged contacts with a single carbon sphere and three hydrogenspheres after the excisions are made, just as it had before. It istherefore established as above stated that the two propaneassemblages, that of f he ordinary paraffin structure and that derivedfrom the tetramethylmethane assemblage, can be partitioned intounit groups of the same form ; in other words, they are polymorphousarrangements of the same molecular groups.The geometricalprocess, inverse to that indicated above, by means of which thesecond kind of propane assemblage can be converted into that oftetramethylmethane, is analogous to Friedel and Ladenburg’sconversion of Wdichloropropane, (CH,),CCI,, into tetramethyl-methane by the action of zinc methyl.The graphic formulz for all the hydrocarbons of the generalmolecular composition CnHp12+2 can be derived from those ofmethane, trimethylmethane, and tetramethylmethane by the i n t 2358 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALduction of methylene groups, CH,, into the formulae in all the waysconsistent with the quadrivalency of carbon.It has been shown inthe foregoing pages that close-packed assemblages of the generalcomposition of the parailins can be constructed which correspondin constitution and configuration with the normal hydrocarbons ofthe series; it has also been shown that other assemblages may bederived which possess geometrical properties exactly representativeof the simple secondary and tertiary paraffins by means of simplesubstitution processes which closely parallel the modes of preparationof these hydrocarbons. The mode in which the geometrical substi-tutions are made renders it clear that similar operations appropri-ately performed will lead to the productioii of an assemblagecorresponding in constitution with any primary, secondary, ortertiary paraffin.The conclusion must thus be drawn that thecontinued prosecution of the method described for derivingassemblages representing the paraffins must lead to a completeparallel between the possibilities of our geomet-rical method forinterpreting atomic space arrangement and the variety of chemicalprocesses of derivation which are so completely pictured with theaid of the ordinary graphic formulze:.The Olefinic Hydrocarbons.The results obtained by means of the above method of derivingclose-packed assemblages, which represent in composition, con-stitution, and configuration all the primary, secondary, and tertiaryparaffins, have been shown to accord with all the available gonio-metric data; although this evidence is small in amount, it appears tobe of a very direct character.The assemblages for the normalparaffins are characterised by being built up wholly from the generalmethylene assemblage by the intercalation of a,dditional hydrogenspheres in appropriate ways. It will now be shown that the reverseprocess, namely, the removal of hydrogen spheres from the generalmethylene assemblage, gives rise to a geometrical feature corre-sponding with the element. of chemical constitution described as anethylenic double bond. By the application of this process ofexcision to paraffinoid assemblages, fresh assemblages can be derivedrepresenting all the open-chain olefines of the general compositionCnHZn, and it will further be demonstrated that peculiarities ofconfiguration, which arise naturally during the process, representthe properties associated with the cis- and trans-isomerism of certainethylene derivatives.The formakion of an olefine may be represented by the chemicaloperation of removing two hydrogen atoms from one t,erminal carbonatom of each of two paraffin molecules, and allowing the t,wSTRUCTURE AND THE CHEMICAL COMPOSITION, EI'C.2359bivalent radicles thus obtained to condense, forming a hydrocarbonmolecule containing an ethylenic double bond ; this correspondswith the product,ion of ethylene by the action of copper on methyleneiodide, and may be thus formulated:CH$, - 21 + CH& - 21 = CH,:CH,.It has been shown that, the orthorhombic and the tetragonal formsof the general methylene assemblage are capable of interconversionFIG. 37n.FIG. 37b.by means of simple adjustment without any violent rearrangement.The described process of excision may be applied to either form,but the tetragonal one lends itself the more readily to its appli-cation; it is the one the employment of which leads to a resultthat can be checked by crystallographic data, whilst that of theorthorhombic form at present does not. The application of theprocess to the tetragonal form of the general methylene assemblagealone is given here; the treatment of the other form is notattempted, first, because it is not at the moment of practicalimportance, and secondly, because the first step in the derivationof an olefinic form from an orthorhombic paraffinoid form maypossibly consist in the passage of the latter t o the tetragonal form.The configuration of the ethylenic grouping, as it presents itselfin a homogeneous close-packed assemblage, is deduced by removingfrom a, face of each of two composite layers, CH,, of the generalmethylene assemblage of the tetragonal form, the small sphereslying in the hollows of the face, and by then keying together thetwo faces thus laid bare. The process itself parallels that whichmay be thus formulated:H*F= + ZC*H = H*C:C*H, I I 2360 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALand is depicted in Fig.37 a and b by superposing b on a ; the sectionof the resulting assemblage of radicles through a line AB is givenin Fig.37c; it is concluded that the presence of such a doublestratum as this is characteristic of an olefine. The only additionrequisite to t,he stratum just described to produce from it theFIG. 37r.arrangement for ethylene is the appropriate insertion of spheres ofvalency volume 1 at each of its faces in the manner alreadydescribed in connexion with the normal paraffins ; the close-packedassemblage composed of the strata thus completed is obtained byarranging a succession of the strata of Fig. 37c with a layer of theF I G . 376.small spheres between each ofthem, such as is shown inFig. 37d (compare Fig. 32).In view of the comparativesimplicity of this process, itwill be convenient at once todemonstrate its application toa specific case in which aslight complicating adjustmentaccompanies the formation ofthe assemblage.Jaeger has described tetra-mdoethylene, C,I,, as crys-tallising in the monosymmetricsystem witha : b : c=2*9442 : 1 : 3.4387,/3=7O044/3O/’ (Trans., 1908, 93, 523).I n this description it isconvenient to change the indices 001, TOl, 501, i l l , and 100to 100, 203, 001, 263, and 203 respectively; the introduction ofthe factor three in this connexion seems permissible in view ofthe pronounced pseudohexagonal character of the compound, andas a result of the change the indices become more symmetricallSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 236 Ldistributed, although numerically somewhat more complicated.' Theaxial ratios are t,hen obtained in the form:n : b : c =1.0891 : 1 : 0.7360 ; B=81"3';whence the equivalence parameters are calculated, with TV = 12, as :The assemblage appropriate to tetraiodoethylene, and also there-3.- : ?/ : z=2'689 : 2'469 : 1 817 ; /3=84"3'.FIG.38n.Fra. 3%.fore to ethylene itself, is constructed on the basis of these values inthe following manner. Carbon spheres are arranged in squareorder so as to be equidistant in t.he same plane, and nearly in contact,as in the general methylene assemblage of tetragonal form depicted inVOL. XCVII. 7 Fig. 29 ; the squares are then converted by a distortion into rhombs,the diagonals of which are in the ratio of x : y. The arrangementand dimensions of the system thus produced are indicated by thelarge circles of Fig.38a. On one face of the layer of carbon spheresare-now placed spheres of volume 1, representing hydrogenFJG. 39a.or iodine,FIG. 39b.one in each of the hollows. If the arrangement of the large sphereswere a square one, each small sphere would touch four large ones, rnshown in Fig. 37 ; as it is, each small sphere makes but three contacts,and symmetry requires that these shall be such that the centres oSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2363the small spheres display the same relative arrangement as the largeones, and are thus equidistant. Their situations are indicated bythe circles marked a in Fig. 38a. The principal hollows now presenton the face of the composite layer to which the spheres a have beenadded are just twice as numerous as the carbon spheres; they arenext occupied symmetrically by other spheres of volume 1, as shownby the circles b and c.The block thus obtained can be regardedas consisting of three layers of spheres, one of large and two ofsmall ones.A second block of spheres similar to the first is now formed andthe two blocks put together, so that the faces on which no smallspheres have been placed fall together and key into one another, eachlarge sphere of one block making contacts with three large spheres ofthe other block. Three contacts of large spheres are so made thatthe shift of the large spheres on the face of the block has theopposite direction to the shift of the small spheres, a, first placed onthe other face.The relative situations of the two blocks are shownby superposing Figs. 38a and 39a, when it is seen that the systemformed has digonal axes parallel to the direction y passing throughpoints of contact of carbon spheres; sections of the double layerof two blocks by two planes perpendicular to those of Figs. 38nand 39a, through the lines AB, CD and EF, GH respectively, areshown in Figs. 38b and 39b. Double blocks of the form thusobtained are fitted together in such a manner that the end layer ofsmall spheres, b and c, of one block serve ils the end layer of thonext double block; thus, if the spheres b are allotted to one doubleblock, those marked c are t o be allotted to the adjoining one.The composition of the completed assemblage corresponds with thatof ethylene or tetraiodoethylene, and its dimensions, x, y and z, arethe equivalence parameters above derived for the latter substance.It will be seen that the assemblage differs merely by it slight adjust-ment and a sheer equivalent to the angle B = 84O3' from the moresymmetrical one constructed to represent ethylene in which thecarbon and hydrogen spheres are in square arrangement.It isinteresting to note that the plane directions with the mmewha.tcomplex indices given above are found to be very important direc-tions in the assemblage when their traces are drawn on the planand section here given.The fact of the limitation of the number of derivatives of thenormal paraffins led van't Hoff to ascribe freedom of rotation to asingly bound carbon atom; a limitation of this kind does not obtainin the case of a doubly bound carbon atom, although the acceptedgraphic representation of the altered molecule and its derivativesare capable of a digonal rotation by means of which it could be7 r 2364 BARLOW AND POPE : TBE RELXTZON BETWEEN THE CRYSTALrepresented.This discrepancy points to the loss of some sym-metrical feature due to the presence of the double bond. Anexamination of the effect on a normal methylene assemblage of theremoval of the double layer of hydrogen spheres and the closing ofthe gap, which, it is suggested, expresses the change referred to,shows that a deterioration of symmetry has supervened ; strings ofcarbon spheres are not continued in the same planes across theplane at which the modification occurs, but a side shift or ‘‘ fault ”is necessitated in order that the two denuded surfaces may fitclosely together.It is suggested that the existence of this breakin the regularity of the strings of carbon spheres makes two differentorientations equally available for the portion of an assemblage lyingbeyond the surface of modification; in other words, whilst in thecase of a normal paraffin assemblage of the tetragonal form theaddition of a, layer, in order to give equilibrium, must be so per-formed that the joined layers have the same orientation, in thecase where a double or ethylenic bond is present, it is equallyf avourable to equilibrium whether the two layers coming togetherhave the same orientation or differ in orientation by 90°.Theparallel which thus exists between the properties of close-packedassemblages and the occurrence of cis- and trans-isomerides amongstthe derivatives of ethylene will be treated immediately in connexionwith the isomerides of the composition C,H,.It should be remarked that the existence of the alternative re-ferred to for the attachment of an added layer is inoperative in thecase of ethylene, and in the cases of compounds equally symmetrical,such as tetraiodoethylene; in all such cases the two resulting formsbecome identical, and thus indicate, as they should do, that thereis but one kind of molecule. The alternative becomes operative,however, in some derivatives of this simple form, since partial sub-stitution of the hydrogen spheres allows two kinds of partitioningto be discriminated which are not interchangeable without re-marshalling.The effects of the presence of the structure repre-sented by the ethylenic bond, as exhibited in cases of homologues ofethylene, will now be traced.The Honaologues of Ethylene.After having traced a peculiarity of geometrical structure in aclose-packed assemblage which corresponds with the double bondpresent in the ethylene molecule, it is desirable to ascertain whetherthe introduction of this geometrical feature into a paraffinoidassemblage leads to the production of the type of assemblagespecifically associated with the presence of an ethylenic bond, Forthis purpose, i t is convenient to consider the four butylenes, C,H,STRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2365which may be regarded as derived from butane and isobutane bythe removal of two hydrogen atoms from the molecule; thesesubstances are (1) cis-s-dimethylethylene, c%>C:C<&H$, (2) trans-Hs-dimethylethylene, c%>":c<cH , (3) ethylethylene (butylene),CH,*CH,*CH:CH,, and (4) us-dimethylethylene (isobutylene),(CH,),C:CH,. Further, in order that the possibilities of close-packing under the specified condition of unit composition may beexhausted, as also those of isomerism of the molecular compositionC,H,, it will be convenient to discuss the assemblages representativeof the remaining two hydrocarbons of the latter composition,3namely, (5) tetramethylene (cyclobutane), CH,<CH2>CH,, and (6)c=2inethyltrimethylene (methylcyclopropane), CH,*CH<FH2CH,'It will now be shown that the process of excising hydrogen sphereswhich has been applied above for the purpose of deriving theassemblage representing ethylene can be applied in three differentways to the normal butane assemblage; these lead to the productionof three distinct assemblages, which represent the butylenes, num-bered (l), (Z), and (3).A similar process applied to the isobutaneassemblage leads to the formation of an assemblage, which representsthe asymmetrical dimethylethylene, numbered (4). I n connexionwith the analogy existing between the geometrical mode of repre-sentation employed and the possibilities of chemical isomerism, it willbe shown that these four methods of applying the process of excisionare the only ones that lead to the production of the geometricalpeculiarity of structure corresponding with the presence of anethenoid double bond ; three other modes of excision are, however,also applicable, two to the butane assemblage, and one to that ofiaobutane; all of these result in the formation of assemblages whichdo not contain the ethenoid peculiarity of geometrical structure.Of the latter assemblages, two are identical and represent methyl-trimethylene (6), which is derived both from the butane andthe isobutane assemblage; the remaining assemblage is that of (5),tetramethylene, and is derived only from the butane assemblage.Since assemblages representative of the four homologues of ethyleneand the two polymethylenes, which constitute all the isomerides ofthe composition C,H,, are derivable from those representing theonly two hydrocarbons of the composition C4Hlo by processes entirelyanalogous to the chemicaI methods of preparing the former hydro-carbons, strong confirmation is afforded of the general accuracy ofthe mode of formulation now put forward.These cases illustratein a striking manner the geometrical property to which has bee2366 BARLOW AND POPE: TEE RELATION BETWEEN TEE CRYSTALascribed the persistence of the tetrahedral disposition of the atomiclinks when substitution occurs ; they consequently throw light onthe precision with which the ordinary formulz indicate the numberand nature of the isomerides obtainable in any particular case,The three modes of excision applicable to the assemblagerepresenting normal butane for the purpose of derivingassemblages representative of the butylenes (I), (a), and (3)are the following.I n a stratum of the normal butaneassemblage of the tetragonal form, four attached layers ofthe composition CH,, and of the square configuration, are present ;to each of the terminal faces of the block an appropriateset of hydrogen spheres has been added, as already explained(p. 2336). The stratum indicated is first divided at the median plane,so that each half consists of t*o layers of the form CH,, to one ofFIG. 40n. FIG. 40b.which an additional set of hydrogen spheres has been added.Fromthe surface of each of the two halves exposed by the separationthe small spheres are now removed, and the two halves are thenrefitted together, making the large spheres of one face fit into thehollows of the other ; this operation may be performed in two ways,one being represented by superposing b on a, and the other bysuperposing c on a of Fig. 40. In these diagrams the groups fittedtogether are of the form H, all the hydrogen spheres attachedto the outer layer of carbon spheres-those representing the methylhydrogen atoms-being omitted for the sake of clearness. Thesuperposition of b on a gives the assemblage corresponding withcis-s-dimethylethylene, and that of c on a the assemblage for thetrans-isomeride.No hydrogen spheres lie between the two denudedlayers of carbon spheres fitted together as described, and the hollows-c-STRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2367on the denuded surfaces from which the hydrogen spheres have beenremoved are now occupied by the carbon spheres of the opposingface. The geometrical operation which has thus been performedupon the normal butane assemblage may be roughly representeddiagrammatically by the following scheme :The assemblage of (3), ethylethylene, is derived from that ofiiormal butane by dividing the latter at the place of either the firstor third linking so as to give as one segment a single layer of theform CH,, with its a.dditiona1 small spheres attached to one faceonly, and, as the other seg-ment, a block or stratum ofthree layers, CH,, with theadditional small spheresattached to one of its boundaryfaces.As before, the smallspheres are removed from allthe hollows of t.he two facesexposed by the separation, andthe surfaces are then refitted;this operation can only be per-formed in one way withoutdestroying symmetry, or rather,the two most symmetrical waysof fitting the strata closelytogether to produce a con-FIG. 40e.tinuous assemblage give identical results.The assemblage for as-dimethylethylene (4) can be obtained fromthat of isobutane, but is most conveniently derived from that oftetramethylmethane, C(CH,),, already described (Fig. 34), byremoving from the latter one-half of the layers which have thecomposition H4C, namely, either those whose median planes passperpendicularly to the plane of the diagram through all the diagonallines BC, or those whose median planes pass through all the linesDE.On removing the strata thus indicated and then refittingthe denuded surfaces, a general arrangement is attained of whichthe large spheres alone are represented in Fig. 41; in this figure theunremoved layers of the composition H4C are marked DE.The three modes of excision which do not lead to the productionof the geometrical feature corresponding with the ethenoid doublebond remain to be dealt with; that which yields the assemblag2368 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALCH corresponding with (5), tetramethylene, CH2<CH2>CH2, is next2described.The assemblage for this hydrocarbon i s derived fromthat of normal butane of the tetragonal form (Fig. 31) by removingthe layers of hydrogen spheres which correspond with the terminalatoms in the paraffin chain, thus obtaining strata of the methyleneform of assemblage, each consisting of four tetragonal layers ofcarbon spheres and the accompanying hydrogen spheres. Eachstratum is next adjusted so as to bring its constituent carbon spheresclose together in fours, as indicated diagrammatically in Fig. 42a and b ; the planes of these sections are perpendicular to those ofFIG. 41.the tetragonal layers. The grouping is so performed that each fourtetragonal layers of carbon spheres and attendant hydrogen spheresfurnish two layers of tetramethylene complexes, as indicated bya and b.A single tetramethylene complex, plan and elevation ofwhich are shown in Fig, 43 a and b , consists of four large spheres inthe same plane and eight small spheres, four in each of two planesparallel to and equidistant from the plane of the carbon spheres.The two remaining modes of excision applicable as already inti-mated (a) to the butane and ( h ) to the isobtitane assemblage, leadto the production of the same molecular unit, that which representsmethyltrimethylene ; the former is applied t.0 the normal butaneassemblage of the orthorhombic form in the following manner.( a ) Alternate layers of the small terminal spheres of the normaSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2369butane assemblage are removed as if for the purpose of condensingthe strata, in pairs so as to form strata of the normal octaneFIG. 42b.assemblage, and each mutilated butane stratum is divided sym-metrically into blocks of the composition CIA, and 3(CH,) respec2370 BARLOW AND POPE: THE RELATION RETWEEN THE CRYSTALtively. The latter blocks are next so adjusted that, as condensedtogether two by two, they form aggregates of trimethylene complexesarranged as is indicated by superposing a and b of Fig. 44; eachstratum consists of six layers of large spheres as shown in thefigure, and, as in the previous case, each small circle represents twospheres. Finally, one-half of the hydrogen spheres are removedsymmet.rically from the outer layers of the double stratum justdescribed, and the outer layers are refitted to the CH, layers fromwhich they were separated, the projecting carbon spheres of oneface of the latter being allowed to fall into the hollows vacated bythe hydrogen spheres last removed ; simultaneously, the small spheresof the added CR, layers are adjusted for close-packing.The preciseeffect of the last process is difficult to trace, but its practicability isindicated by the facts that when the refitting has taken place, eachsphere of the altered trimethylene layers is still immediately sur-FIG. 43a. PIG. 43b.rounded by the large number of spheres appropriate for very close-packing, and that no destructive deformation of the original CH,arrangement is necessitated. The refitting of the layers is repre-sented by the equation : 3(CH,) - H + CH, = CH,.C€I<ctl 9 andthe assemblage attained is, as indicated by its constitution, composedof trimethylene complexes, from each of which a hydrogen spherehas been removed, grafted on to modified methyl complexes.( b ) A different assemblage of the same trimethylene complexes isderived from that of trimethylene by an appropriate excision ofhydrogen spheres in the manner next described. I n Fig. 35, repre-senting the arrangement of the ca.rbon spheres in the trimethyl-methane assemblage, cavities and portions of cavities, which liebetween two planes of which the traces are marked FG, IIK, areavailable for the reception of hydrogen spheres; the central entirecavities are each of the magnitude requisite for the reception ofy I€,STRU OTURE AND THE CHEMICAL COMPOSITION, ETC.2371four hydrogen spheres, and the portions or half cavities have halfthis magnitude. Whilst maintaining the same configuration of the -groups of four largespheres as is indicated inthe figure, the two OPPD-site sets are now allowedto approach until thecavities and portions ofcavities afford only one-half the previous accom-modation for hydrogenspheres; the effect ofdiminishing the accom-modation offered by thecavities and portions ofcavities to one-half theoriginal amount is indi-cated in Fig. 45. Finally,without re-marshalling,such mutual adjustmentsare conceived as willadapt the various cavitiesbetween the large spheresto the close-packing ofthe appropriate numbersof hydrogen spheres ;these adjustments willresemble, in general,those previously de-scribed in connexion withsimpler cases.The unaltered mar-shalling of the largespheres in each moleculargroup which is thus pre-scribed, and the advance-ment of large spheresto occupy cavities leftvacant by the removal ofthe small ones, is fittinglyrepresented by the transi-tion from the graphicFIG. 44n.FIG.44b.formula of triniethylmethane to that of methyltrimethyleneimmediately accomplished by removing a hydrogen atom from eac2372 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALof two neighbouring branches of the molecule of t,he former, andrestoring the linkage equilibrium by adding a link between thecarbon atoms concerned, thus :I n connexion with the two methods just described for derivingFIG.45.an assemblage representing methyltrimethylene, it is suggested thatthe course followed involves the initial formation and the subsequentpreservation of an approximately regular tetrahedral dispositionof the contacts of the carbon spheres with other spheres of the samemolecular unit ; the functional identity of the molecular units hereindicated will necessitate that the two assemblages should beregarded as an example of polymorphism.The arguments stated and the data given in the previous pagesindicate that an ethenoid compound is derived from the correspond-ing paraffinoid compound by the removal of the requisite proportionof hydrogen spheres from the assemblage, and the subsequent con-traction necessary to restore close-packing to the assemblage.Itwould consequently be anticipated that pairs of substances ofcomplex molecular constitution, the members of which differ in thata paraffinoid element, *CH,-CH,*, in the one is substituted by aSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2373ethenoid element, *CH:CH-, in the other, might afford frequentinstances of intimate crystallographic relationship ; in such cases,the substitution just mentioned should occur in such a manner thatthe closing up of the assemblage would be manifested by a contrac-tion in the directicn of one of the properly selected equivalenceparameters. Examples of this kind are not unconimon, and onetnav be here auoted.J aAcenaphthene, CloH6<XE: is morphotropically related toacenaphthylene, (Billows, Zeitsclt, Kryst. Mirt., 1903,37, 396); both belong to the orthorhombic system, and t,he axialratios are respectively :Acenaphtheue, n : b : c-0'5903 : 1 : 0.5161.Acenaphthylene, n : Z, : c=0*5926 : 1 : 0.4996.The equivalence parameters corresponding with these axial ratliosm e :Acenaphtiieno, x : y : 2=3'3959 : 5.7527 : 2.9689.Acenaphthylene, 2 : y : z=3'4017 : 5'7404 : 2.8678.Differences - 0'0058+0~0123+0'1011.It is observable that the differences between correspondingequivalence parameters for the two substances are negligibly smallin the directions x and y, but appreciably large in the directionof z ; in this case the replacement of the para.ffinoid by the ethenoidstructural element has involved a closing up of the crystallineassemblage, which is only experimentally appreciable in the directionof the c or z axis.An equally striking example is afforded by themorphotropic relationship observed between dibenzyl and stilbene,which is referred to later (p. 2379).W = 5 8117=56.The Acetylene Series, C1LH2n-2.The space formation of spheres, which corresponds with thecharacteristic acetylene grouping, -CiC*, is rather more difficult totrace than that representing the double linking present in ethylene,but owing to the extreme simplicity of the molecular compositionof the first member of the acetylene series, the possibilities to besubmitted to consideration are so limited in number thatexamination of the arrangement to be described, which fulfils someof the principal conditions requisite, leaves practically no doubtthat it is the one sought.The assemblage representing acetylene itself is derived from aclosest-packed cubic assemblage of spheres, each of the volume 4(Fig. l), in the following manner.Each of the large cavities inthe assemblage, which are found at the centres of groups of si2374 BARLOW AND POPE: THE RELATION BETWEEN THE CRYSTALspheres and are just its numerous as the spheres, is occupied bya smaller sphere of such magnitude as just to touch the six spheresenclosing the cavity; the assemblage represented in Fig. 46 is theresult. The smallerspheres which can thusbe inserted are of amagnitude less thancorresponds with thevalency volume 1, andaxe next to be ex-panded until theyattain this volume.I f the relativearrangement of theFIG.46.FIG. 47.centres of both kindsremained unchangedduring t,he expansion,i t is evident that allthe contacts betweenthe larger sphereswould be broken, asshown in Fig. 47, butit is possible for thelarge spheres to pre-serve some of theircontacts, notwithstand-ing the presence ofthe smaller spheres, ifslight mutual adjust-ment occurs. Theassemblage can be re-garded as composed oflayers the planes ofwhich are parallel to aplane drawn throughopposite edges of acube of the fundacmental space-lattice ;such a layer, viewedprior t o the adjust-ment, is representeddiagrammatically by the continuous lines in Fig.48. Let thereforeeach larger sphere continue in closest contact with one other sphereof its own size, and let the partners be so selected that the contactSTRUCTURE AND THE CHEMCAL COMPOSITION, ETC. 2375of sphere with sphere are distributed through space as evenly aspossible. The latter condition is fulfilled if the points of contactare approximately at the centres and angles of a cubic partitioningof space such that the length of a cube edge equals the translationof the assemblage along the directions in which carbon and hydrogenspheres are found placed alternately in contact. The assemblagethus modified consists of groups of a composition correspondingwith acetylene, C,H,; the projections of the points at which thelarge spheres come into cont.act when the adjustment occurs aremarked A in the diagram.The geometrical properties of theadjusted assemblage thus constituted parallel the chemicalbehaviour of acetylene, as will be perceived below in connexion withFIG. 48.the homologues of the hydrocarbon. Owing to the fact that nocrystallographic data are available for directly checking thegeometrical results, the exact nature of the processes by which thesucceeding terms of the acetylene series are arrived at, and theprecise forms of the assemblages, are difficult to determine; thefollowing is put forward, however, as the probable mode of derivingthe correct form of assemblage for methylacetylene (allylene),C H, C i CH .Methylacetylene ( A llylene).From one of the two similar faces of a layer of complexes suchas is depicted in Fig.48, the small spheres axe removed, so that, theresidue represents the radicle, *CiCH ; the stratum is then slightlydistorted by diminishing its thickness and consequently increasingits face dimensions so its to make the latter equal to those of a laye2376 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALof the unadjusted orthorhombic ethane assemblage, Fig. 49b. Onthe denuded face of a stratum of this kind, which is shown inFig. 49a, is next grafted a stratum of methyl complexes (Fig. 49b),namely, a half stratum of the ethane assemblage (Fig. 23); theprocess is represented diagrammatically hy superposing Fig.497,on Fig. 49u. The composition of the resulting compound stratumFIG. 49b.is represented by the formula CH,*CiCH, and the correspondingequilibrium assemblage will consist of a number of such strata keyedinto one another ; succeeding strata will be oppositely orientated,and the contacts between them will consequently be of two differentkinds occurring alternately. *One kind will resemble the terminalcontacts found in the acetylene assemblage, as above presentedSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2377and the other, those found in the normal paraffin assemblage of theorthorhombic form. As in most. of the preceding cases, themarshalling described is represented in a simple form, and theFIG. 50a.FIG.50b.assemblage must therefore be conceived to be subjected to suchadjustmentl as is requisite t o produce closest-packing of this mar-shalling. It is important to observe that the assemblage justVOL. XCVII. T 2378 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALdescribed can be distorted so as to assume a tetragonal form withoutany considerable alteration of the environment of the constituentatoms; perhaps the simplest way of describing the result is to buildup an assemblage from two kinds of tetragonal strata representingrespectively the acetylenic remnant, *C ICH, and the methyl radicle,*CH,. The former is obtained from a tetragonal acetylenic layer(Fig. 47) by removing the hydrogen spheres from one of its faces,as shown by Fig.500, whilst the layer representing methyl is derivedfrom the tetragonal ethane assemblage (Figs. 29 and 30), and itsprojection is represented diagrammatically in Fig. 50b. It isremarkable that in putting the two layers together the terminalface of the ethane stratum has in this case to be turned towardsthe denuded a.cetylene face, so that what was the inner face is nowoutwards; this is represented by superposing b on a of Fig. 50. TheFIG. 51. FIG. 5 2 .methylacetylene strata, CH,*C i CH, its before, present oppositeorientations in succeeding layers ; in the tetragonal asemblage nowbeing described, junctions, such as occur in acetylene, alternate withjunctions having much the same marshalling as those of tetr%methylmethane strata (p. 2348).The diagrams merely indicate themarshalling, and minet be supposed subjected to adjustment whichrenders the packing closer.The assemblage representing the next homologue of the series,ethylacetylene, CH,*CH,*CiCH, results from employing a butanestratum instead of an ethane one in the geometrical process describedabove.It has been shown in the foregoing pages that the geometricalmethod indicates that the conversion of a paraffin assemblage intothat of the corresponding olefinic and acetylenic hydrocarbon occursby the excision of lrtyers of hydrogen spheres, appropriately selected,in such a manner that the dimensions of the residual paraffinoidradicle suffer but little change. The paraffinoid, olefinic, oSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC.2379acetylenic assemblage can, in fact, be regarded as consisting of aparaffinoid assemblage into which have been appropriately inter-calated layers of the composition *CH,*CH,*, *CHiCH*, or *C:C*respectively, these layers being dimensionally compatible with theparaffinoid part of the assem-blage. I n this dimensional com- FIG. 53.patibility between the threeelements of constitution justmentioned is found a completeexplanation of the frequentoccurrence of close morphGtropimc relationships betweencorresponding paraffinoid, olefinic,and acetylenic compounds, andfor which no cause has hithertobeen traced. For the presentit will suffice to quote theaxial ratios for the monosymmetric dibenzyl, stilbene, and tolane asillustrating the relationship referred to (Boeris, Zeitsch.X;_'?.gst. illin..,1901, 34, 298):a : b : c . P.Dibenzyl, Ph'CH;CII2*P1i ............ 2.0806 : 1 : 1.2522 115"54'Stilbeiie, Ph*CH:CEI*Ph.., ........... 2 1701 : 1 : 1'4003 114 6Tolane, Ph*CiC'l'h .................... 2.2108 : 1 : 1.3549 115 1T h e Conversion of 9 cetylene De?.ivatiues i n t o AromaticHydrocarbons.The assemblages just put forward as representing acetylene andits homologues have been constructed in accordance with the prin-ciples of close-packing applied in numerous other cases, the existenceof this condition consisting in the large number of spheres in contactwith, or close proximity to, each sphere. Although uncorroboratedto any considerable extent by crystallographic evidence, the correct-ness of the representation is strongly supported by the fact thatthe tetragonal assemblages described immediately provide amechanism which can be shown to illustrate the well-known con-version of acetylene derivatives into aromatic hydrocarbons.The acetylene assemblage has been derived from the closest-packed'assemblage of equal spheres of the valency volume 4 by forcingspheres of valency volume 1 into the interstices which occur at thecentres of close octahedral groups of six spheres and are as numerousas the large spheres.Before the insertion of the smaller spheres,the assemblage can be regarded as composed of identical groups ofsix spheres, and similarly, after the insertion of the hydrogen spheres,as built up of t,he composite groups of twelve spheres, six large and7 Q 2380 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALsix small, depicted in Fig.51. The latter groups, however, can bereadily distorted into groups of the benzene configuration shownin Fig. 52, which has been previously described (Trans., 1906, 89,1693), and is shown in rough perspective in Fig. 53; this is easilyseen by compa,ring Figs. 51 and 52. The acetylene assemblage ofFig, 48 can, consequently, be regarded as built up of units of thecomposition C,H,, each representing an acetylene molecule, or asconsisting of units of the composition C,H,, each of which representsa distorted benzene complex.The choice between the two kinds of partitioning can be expressedby the number of large spheres in immediate contact; if these touchtwo by two, while the pairs are not in contact but are kept apart bythe smaller spheres, the acetylene grouping is indicated, but if thelarger spheres form groups, each containing six carbon spheres inring contact, each sphere of a layer of three being attached to twospheres of the neighbouring layer of three, the benzene configurationis portra.yed.It is conceivable that the simpler form of groupingmay give closest-packing when the ratio of the sphere magnitudes lieswithin certain narrow limits, and that when these limits areexceeded in one of the two directions, the other form of groupingmay be brought about; the polymorphous forms of assemblage forbenzene previously described would then follow from further changeof the conditions.The passage from one grouping to the otherabove indicated will thus occur at some critical condition of tem-perature or the like; it involves no re-marshalling but some slightadjustment of the relative positions of the two sizes of spheres.The slight adjustment which is thus requisite to the conversion ofthe acetylene assemblage into an aggregate of units having thebenzene Configuration is the geometrical analogue of the conversionof acetylene into benzene by heat.The acetylene assemblage, in accordance with our previous results,must be regarded as practically identical in form and relativedimensions with the assemblages of the halogen derivatives of thehydrocarbon; by replacing each hydrogen sphere in it by an iodinesphere of approximately the same valency volume, the assemblagerepresenting the crystalline di-iodoacetylene would be obtained.Von Baeyer's observation (Ber., 1885, 18, 2269), that di-iodo-acetylene, C,I,, is converted into hexaiodobenzene by slight warmingor the action of light, is in complete accordance with this.A similar kind of mechanism elucidates t'he polymerisation whichoccurs when monoido- or monobromo-acetylene is preserved in thecrystalline or dissolved state, and which leads to the production ofthe 1 : 3 : 5-tri-iodo- or tribromo-benzene respectively (von Baeyer,Zoc. c i t .) . For the representation of these changes, the hydrogeSTRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 238 1spheres on one side only of the stratum of acetylene compIexes arereplaced by iodine or bromine spheres of approximately the samevalency volume as hydrogen; the distortion of the assemblage formonoiodo- or bromo-acetylene thus obtained leads to the re-partitioning in the sense of the equation:3CH iC!I = C,H,T, (1 : 3 : 5 ) .The compound tetragonal assemblage for allylene, CH,*C;CH,depicted in Pig.49, was obtained by the intercalation of two kindsof strata, those, namely, of the acetylene and methane radicles.Polymerisation strictly corresponding with that observed is broughtabout geometrica.lly by altering the acetylene stratum just as in theprevious case; the three carbon spheres of a newly constitutedbenzene complex thus formed, which lie in one of the two planes,become respectively attached to three methyl groups of the adjoiningstratum so as to give the symmetrical constitution of mesitylene.I n the derivation of the assemblage for allylene, the hydrogenspheres on one side only of the acetylene layers were replaced by alayer of methyl complexes; if the hydrogen spheres on both sides ofeach acetylene layer are replaced by layers of methyl complexes, theassemblage produced represents that of the symmetrical dimethyl-acetylene (crotonylene), CH,*C iC-CH,.The passage by slight dis-tortion of the acetylene layers to the benzene configuration involvesthe conversion of each set of three dimethylacetylene complexes intoone molecular complex of hexamethylbenzene in a manner preciselyparalleled by the observed facts.If oxygen spheres are introduced into the allylene assemblagedescribed above in the proportion of one for each acetylene unitpresent, and two hydrogen spheres are simultaneously introducedfor each oxygen sphere, in accordance with the second geometricalproperty, an assemblage is obtained which has a constitution corre-sponding with that of acetone, CH,*CO*CH,.The removal of theelements of water from this assemblage, so as to convert it into theallylene assemblage, accompanied by the slight distortion whichcauses the assemblage to pass to the benzene form, correspondsgeometrically with the observed conversion of acetone into mesityleneby the dehydrating action of sulphuric acid. The following methodmay be applied to the production of an assemblage for acetone, inwhich the process referred to can be readily traced.The general methylene assemblage described above (p.2326) canbe distorted to an acute rhombohedral form without sensibly affect-ing the closeness of the packing; the volume of each rhombohedralunit cell, like that of the orthorhombic cell before described, isthat proper for one radicle unit, CH2. The corners of the cell areoccupied by the centres of carbon spheres, and the cell contains a2382 BARLOW AND POPE : THE RELATION BELWEEN THE CRYSTALits centre a pair of hydrogen spheres, the pairs being similarlyorientated. The resulting assemblage can be traced in the followingsimple manner. The assemblage may be regarded as consisting ofsimilar layers of the same composition as the layers depicted inFig.19, the planes of centres being parallel to a plane drawnthrough the axis of a cell to contain one of the rhombohedra1 edgeswhich intersect this axis; a constituent layer can be derived ifthe configuration of a single unit cell is ascertained in the followingmanner .Two circles, centred a t A and C, of which the diameters are inthe ratios of those of the carbon and hydrogen spheres, are drawnin contact (Fig. 54); on the line joining the centres, AC, a semi-circle, AVC, is erected, and AC is produced to cut the smallercircle in L. The line LH is drawn perpendicular to AL, AL istrisected in D, and DV isdrawn perpendicular to AL tointersect the semicircle in V,A and V are joined, and thejoin produced to cut LH in 13;VH is then bisected in B, andwith B as centre a circle equalto circle A is drawn.Since AD=1/3 AL, AV=1 13 AH = VB ; theref ore, sinceAVC is a right angle, AC=CB, and circle C, whicht,ouches circle A, dso touchescircle B.L is now used as acentre of symmetry, aboutwhich points, lines, and circlesFIG. 54.W are symmetrically repeated, asahown in the figure; theparallelogram ABFG is the section of a rhombohedron ofthe form required, and the circles centred a t A, By F, andG are the sections of carbon spheres of which the centres lie atthose angular points of the rhombohedron which are intersectedby the plane of the section depicted; the small circles indicated arethe sections of hydrogen spheres enclosed, each having contactwith the other and with three carbon spheres lying on one sideof L in a plane perpendicular to AL as well as with one carbonsphere of which the centre lies on this line.For, if the line ALFbe made a trigonal axis, and by successive rotation through 120°about it, four other points are located from the points B and G,while points A and F remain unmoved, the eight points thuSTR UCTURE AND THE CHEMICAL COMPOSITION, ETC.FIG. 55.2383FIU. 56a2384 BARLOW AND POPE : THE RELATION BETWEEN THE CRYSTALFIG. 56b.FCG. 56c--------00I 1 STRUCTURE AND THE CHEMICAL COMPOSITION, ETC. 2385indicated are connected by the property that the six points noton the axis are equidistant from it and lie three and three ontwo planes which trisect the axis AF, a property characteristic ofthe angular points of a rhombohedron.The proof of the existenceof this property lies in the fact that the traces of the planes referredto, being the horizontal lines through B and G, respectively trisectthe semi-axes AL and FL.When space has been partitioned by means of three sets of parallelequidistant planes into rhombohedra of the form indicated, andcarbon spheres have been placed with centres at all the angles,while pairs of hydrogen spheres occupy the cell centres, each largesphere is in contact with eight small spheres and almost in contactwith six large spheres, while each small sphere touches four largespheres and oneasmall one. This kind of arrangement can betraced in Fig.55, which shows layers comtructed according to thecell conditions derived above ; the continuous and discontinuouslines respectively depict projections of succeeding layers.I n order to derive from the methylene assemblage of the formthus described an assemblage for acetone, CH,*CO*CH,, three suc-ceeding layers are taken, and an oxygen sphere substituted for eachpair of hydrogen spheres of the central layer pf the three; thiscan be done without any sensible change in the form of therhombohedra1 cell. A number of sets of three layers thus modifiedmust then have hydrogen spheres added, just as in the case of thepreviously described methylene assemblage, so as to produce stratawhich appropriately represent the formula of acetone ; the resultingassemblage in its most symmetrical condition is indicated by super-posing b on a of Fig. 56, a representing the two layers, CH, andCO respectively, with the terminal hydrogen spheres added, and Z,representing a single layer, CH,, with its terminal hydrogenspheres.Geometrical complexes of the composition OH, can be readilyrecognised in the assemblage described, each oxygen sphere beingnearly in contact with four hydrogen spheres, two above and twobelow the plane of the layer. The withdrawal of the pairs ofhydrogen spheres of one of the layers simultaneously with the oxygenspheres of the next layer, with which they are nearly in contact,deprives the middle carbon layer of all its smaller spheres, andleaves but one hydrogen sphere, namely, the end one, to be allottedto each of the carbon spheres of an end layer; this, when theassemblage is closed up after the extraction of the OH, complexes,leads to the marshalling above deduced for allylene, CH,*CiCH, andsubsequently the deformatioii already referred to converts theallylene assemblage into that proper for meeitylene (p. 2381)2386 BAKLOW AND POPE : THE RELATION BEI'WEEN THE CRYSTALA mechanism similar in kind to that explained and illustratedabove is apparently applicable to the more complex cases presentedby the various pyridine, quinoline, and quinaldine syntheses.The geometrical simplicity of the operation by which the elementsof water can be introduced into an acetylenic assemblage is com-pletely paralleled by the ease with which acetylene, CIiIiUH, reactswith water under the influence of a catalyst to yield acetaldehyde,CH,*CHO. I n order to represent the assemblage correspondingwith the latter substance, two of the layers of a methylene assem-blage of rhombohedra1 form, as just described, are requisite, thepairs of hydrogen spheres in one of the two layers being exchangedfor single oxygen spheres. The appropriate addition of hydrogenspheres at the opposite faces completes a stratum correspondingwith the constitution of acetaldehyde; the latter is represented bysuperposing c on u of Fig. 56.I n connexion with the distorted configuration (Fig. 51) justdescribed as an intermediate form displayed by the benzene complexduring ibs production from acetylene, it is significant that unitshaving this configuration can be fitted together to make an a.ssem-blage which is compatible with the axial ratios and crystalline formof benzene itself, but which is not identical with the benzene assem-blage previously described (Trans., 1906, 89, 1694, Fig. 3). ThSTRUCTURE AND THE CHEMICAL COMPOSlTION, E'L'C. 2387somewhat remarkable fact that the same spheres present in thesame proportions are capable of two widely different arrangemeiitspresenting almost the same crystalline form and axial ratios istraceable to the spheres occurring in continuous strings in two ofthe three axial directions; thus, in the earlier assemblage justreferred to, the large spheres range in contact in the direction ofthe axis 9, and large and small spheres alternately range in contactalong the direction of the axis z . The dimensions y and z closelycorrespond, in fact, with twice the diameter of a carbon sphere andto the sum of the diameters of a carbon and a hydrogen sphererespectively ; any assemblage in which carbon and hydrogen spheresrange in this manner along directions of translations will con-sequently be morphotropically related to the benzene assemblagepreviously described. The assemblage of the distorted units ofFig. 51 is shown diagrammatically in Fig. 57, in which each ofthe parallelograms indicated marks the projection of the centreportion of a column of benzene complexes of which the axis isperpendicular to the plane of the figure; the sphere centres of eachsingle molecular unit are projected on the outline of some one suchparallelogram. The partitioning of this diagrammatic assemblageinto molecular complexes can occur in several different ways, whichproduce identical results ; the parallelograms are drawn appro-priately for two of these ways, the column indicated by a singleparallelogram being divisible into molecular units in two ways(compare Trans., 1906, 89, 1696). The values of z and y used inthe construction of Fig. 57 are those calculated for crystallinebenzene, in whichx : y : z=3.101 : 3.480 : 2.780.The assemblage shown in Fig. 57, being unadjusted, is equallyapplicable to acetylene and benzene; it shows neither of the kindsof coalition of spheres to form a complex which have respectivelybeen described as productive of molecular units proper to thesecompounds. This accounts for the marked flattening of the sphereswhich is found to be necessary in order that they may be packedinto the space accorded by the benzene valency volume of IY=30.I n three directions in the assemblage, namely, one perpendicular tothe plane of the diagram, and two, those of the diagonals MN, PQ,the large and small spheres alternate. I,n the diagram they arerepresented as precisely in line, but this will not be strictly thecase, especially along the directions of the diagonals ; increasedcloseness of packing, and therefore less flattening, will result froma slight zigzagging of the positions of the two sets of centres of thesame string.The conclusion referred to, that continuous strings of spheres ar2388 GREEN AND WOODHEAD: ANILINE-BLACK BNDpresent in which the two sizes alternate, throws light on thenumerous cases in which the value of the 2; axis for benzene is veryapproximately presented as one of the equivalence parameters ofbenzene derivatives ; many such instances have been recorded byJerusalem (Trans., 1909, 95, 1275) and by Armstrong (this vol.,p. 1578).UNIVELSITY C H EM IUA L LA BOILATOIIY,C A JI B HI DG E

ISSN:0368-1645    

DOI:10.1039/CT9109702308

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

2388 GREEN AND WOODHEAD: ANILINE-BLACK BNDCCXLIII.-Ariiline-blacl% and A llied Compoimds. Part I.By ARTHUR GEORGE GREEN and ARTHUR EDMUND WOODHEAD.ALTHOUGH the recent researches of Willstiitter and his pupils(Willstatter and Maore, Ber., 1907, 40, 2665; 1. SOC. Dyers, 1908,24, 4; Willstatter and Dorogi, Ber., 1909, 42, 2147, 4118) haveadded much of value to our knowledge of the complex oxidationproducts of aniline, the constitution of aniline-black and of itsintermediate products still cannot be regarded as completelyelucidated. The view advanced by Willstatter, that these com-pounds are all to be regarded as indamine-like derivatives of theeight-nucleal chain compound (leucoemeraldine) :NH NH NH NH/\/\/\ /’\/\/\ /\/\/\ /\/\/\I I I I I I I I I l l 1\/ \/\dH\/ \/\i& v\/,J O N E r z -will scarcely gain acceptance without further evidence.AsBucherer has pointed out, it might a priori be expected that sub-stances of such a type would exhibit a high degree of instability,and would readily decompose into simpler compounds under theinfluence of acids, etc.Amongst other arguments in support of the chain structure,Willstatter has shown that the qua.ntitative conversion into p-benz+quinone is only compatible with the existence of di-para-connexions,and is entirely opposed to an azine structure, such as that suggestedby Bucherer (Bey., 1909, 42, 2931):6 6 H, m 5 c P 5I n respect to the validity of t.his argument, it is, however, necessaryto point out that a sharp distinction must be made between thALLIED COMPOUNDS.PART I. 2389primary oxidation products of aniline (emeraldine, nigraniline, etc.)and the condensation products of these with aniline (“ ungreenableaniline-black ’7, which latter alone can be properly regarded as trueaniline-black. Willstatter’s experiments refer only to the formerclass of compounds, and it yet remains to be shown what yield ofp-benzoquinone is obtainable from the latter. It is quite con-ceivable, and in fact probable, that whilst the former possess adi-para chain or ring structure, the “ ungreenable aniline-black,”that is, true anilincblack, is an azine (Green, The Chemical Tech-nology of Aniline-black, 7th Internat. Congress of AppliedChemistry, London, 1909; J . SOC. Dyers, 1909, 25, 188).Only the“ ungreenable aniline-black ” can be correctly regarded as a highlystable compound ; the primary oxidation products probably owemuch of their apparent stability to their insolubility in water andaqueous solvents, for when dissolved in pyridine, etc., they exhibita much greater tendency to undergo change.The view held by Willstitter that ‘‘ ungreenable aniline-black ”is a compound of the same type as the primary oxidation products(that is, contains an eight-nucleal chain, and only differs from theprimary products in the degree of oxidation and the replacementof the terminal N H by 0), is opposed, in our opinion, to theexperimental facts. Were this view correct, the behaviour withsulphurous acid of the two oxidation stages he describes should bethe same, that is to say, both compounds should be reduced to thegreen monoquinonoid stage, and by the application of a, strongerreducing agent all should be reduced to the mother substance, thatis, to the oxygen analogues of leucoemeraldine :NH NH NH NHFurthermore, this reduction-product, like leucoemeraldine itself,would certainly be a tolerably stable substance, giving, on airoxidation, only the lowest quinonoid stage, and requiring theapplication of a strong oxidising agent to reconvert it into theoriginal tri- or tetra-quinonoid compound.These properties are notexhibited either by the preparations described by Willstatter as“ hydrolysed triquinonoid and tetraquinonoid blacks,” or by the“ ungreenable aniline-black ” produced on the fibre.The latter isnot reduced at all by sulphurous acid, and by stronger reducingagents, such as hyposulphites, it is converted into a leuco-compoundwhich is rapidly re-oxidised by air to the original “black,” andthat apparently without passing through any lower stage ofoxidation. Moreover, the facts known respecting the conditions o2390 GREEN AND WOODHEAD : ANILINE-BLACK ANDformation of ‘‘ ungreenable aniline-black ” clearly show that itcannot be a product of further oxidation alone, but is a con-densat.ion product with aniline of a different type to the simpleroxidation products from which it is formed (Green, Zoc. c i t . ) .I n order to throw more light on this complicated subject, it hasappeared to us necessary to obtain, in the first instance, furtherevidence for the molecular weight and constitution of the primaryoxidation products (emeraldine and nigraniline), and we haveattempted to do this by determining, on the one hand, the quantityof hydrogen required to reduce these products to Ieucoemeraldine,and, on the other, the quantity of oxygen necessary to oxidise eachstage into the next.The data obtained in this manner, combinedwith the fact that we have been able to recognise four distinctstages of oxidation of leucoemeraldine, support Willstatter’s viewof an eight-nucleal molecule, but do not agree with the constitutionassigned by Willstatter and Dorogi to the compounds they prepared.Assuming the correctness of the eight-nucleal structure for theprimary oxidation products, it still remains an undecided questionwhether the aniline residues are to be regarded as united in anopen or in a closed chain, but without attempting to decide thispoint we shall make use of the open-chain formulz to expressprovisionally the analytical results.The constitution of ‘ I ungreen-able anilineblack” we reserve for discussion in a later com-munication.Before proceeding to a consideration of the results obtained, it isdesirable to attempt to clear up some of the existing confusionregarding the various oxidation products of aniline and theirnomenclature, Much of the obscurity in this subject arises fromthe fact that no criterion of purity has hitherto existed, and thatthe products obtained have been doubtless largely mixtures.Unsuitable nomenclature has still further added to the confusion.Thus the name “ emeraldine,” which properly belongs to the firstacid-oxidation product of aniline-a violet-blue base giving greensalts, and well known to dyers of aniline-black-has been transferredby Willstatter and Moore to an entirely different compound, namely,the blue imide obtained by polymerisation of phenylquinonedi-imide,which was apparently first mistaken for emeraldine by Caro.Onthe other hand, for the true emeraldine, originally so-called byCrace-Calvert and Lowe, the name ‘‘ triquinonoid aniline-black ” isnow proposed by Willstatter and Dorogi, although emeraldine isneither black nor (as will be shown later) is it triquinonoid. I njustification for this confusing and unnecessary transfer of names,Willstatter and Dorogi advance the incomprehensible plea that“ technisches Emeraldine langst nicht mehr existirt.ALLIED COMPOUNDS.PART I. 2391The various oxidation products which have been described underthe name of aniline-black hy the earlier authors (Muller, Nietzki,Kayser, Guyard, etc.) are lacking in any criterion of purity orindividuality beyond that furnished by elementary analysis, whichin this case is quite inconclusive and valueless. The discovery thatthe primary oxidation products (emeraldine and nigraniline bases)are readily soluble in somewhat diluted organic acids, such as 80 percent. acetic acid and 60 per cent, formic acid (the former basegiving a green solution, and the latter a blue), whilst the highercondensation products are insoluble in these solvents, 1ia.s providedus with a valuable means for diagnosis and separation, by means ofwhich we have been able to show that all the above-mentionedso-called “ aniline-blacks ” consist, mainly of emeraldine andnigraniline mixed with varying proportions of higher condensationproducts. These I‘ blacks ” prepared in substance therefore do notproperly correspond with the aniline-black produced on the fibre,since in the latter case the higher condensation products are eitherexclusively present (ungreenable blacks) or largely predominate(greenable blacks).In order to simplify the nomenclature, we propose that the term“ aniline-black ” should be restricted to the higher condensationproducts (ungreenable black), whilst the original names “ emerald-ine ” and “ nigraniline ” should be retained for the primaryoxidation products.As, however, there is a stage of oxidation belowemeraldine and one above nigraniline, we propose for these thenames “ protoemeraldine ” and “ pernigraniline.” All four sub-stances, protoemeraldine, emeraldine, nigraniline, and pernigraniline,are quinonoid derivatives of the same parent substance, to whichwe have given the name “ leucoemeraldine.” Into this compoundthey are all converted on reduction, and from i t they can all beproduced by oxidation. At present the protoemeraldine stage hasonly been obtained in the o-toluidine series, whilst pernigranilineis too unstable to isolate in a dry state.Emeraldine.This compound is the first clearly defined stage in the oxidationof aniline in an acid medium, whatever the oxidising agent employed.When a chlorate is used, the reaction tends in part, to at onceproceed further with production of more or less nigraniline, butwith hydrogen peroxide, if not used in excess, the oxidation stopsat the emeraldine stage.If the reaction is effected in the cold andin the presence of an excess of acid, emeraldine and nigranilineare nearly the sole products, but if the mixture is neutral or onlyslightly acid, a certain quantity of condensation products (ungreen2392 GREEN AND WOODHEAD : ANILINE-BLACK ANDable black) is also produced. An excess of acid is therefore anecessary condition for preparing eineraldine in a pure state.Asthe result of a series of experiments, proportions corresponding with1 mol. of aniline hydrochloride to 1.33 mols. of oxygen and 1 mol.of hydrochloric acid were found the most suitable.Emeraldine is also produced by the further oxidation of the blueimide, C6H,-NH*C,H4*NH*C,H4*N:C,H,:NH, of Willstatter andMoore (termed ‘ I emeraldine ” by these authors).I. A solution of 100 grams of aniline hydrochloride, 42 grams ofsodium chlorate, and 46.5 C.C. of hydrochloric acid (33 per cent. HCl)in 1800 C.C. of water, to which 2 drops of syrupy vanadium chlorideare added, is kept in the cold for from two to three days. Theprecipitate is then collected, washed thoroughly with water, basifiedby mixing the paste with dilute ammonia in a mortar, finally washedwith alcohol and with water, and dried at 3 5 4 0 O .The productthus obtained contains a varying amount of nigraniline, which maybe readily converted into emeraldine by warming the precipitatewith dilute hydrochloric acid before basifying. Pure emeraldinemay also be obtained by dissolving the crude base in 50 parts of80 per cent. acetic acid, filtering from any insoluble matter, re-precipitating by addition of dilute hydrochloric acid, collecting thehydrochloride, and finally basifying the precipitate wit-h ammonia.During this process the nigraniline present is converted intoemeraldine.11. A solution of 50 grams of aniline hydrochloride in 24 litresof water, to which is added 135 C.C. of hydrochloric acid (33 percent.HCl), 380 C.C. of hydrogen peroxide solution (4.6 per cent.),and 0.5 gram of ferrous sulphate, is kept in the cold for twenty-fourhours. The precipitated emeraldine is collected, washed, andbasified with ammonia.111. Ten grams of paminodiphenylamine are dissolved togetherwith 27 C.C. of hydrochloric acid (33 per cent. HC1) in 1 litre ofwater. After cooling t o 0-5O by addition of ice, 78 C.C. of hydrogenperoxide (4.7 per cent.), followed by 0.1 gram ferrous sulphate, areadded. The hydrogen peroxide used wits rather more than twicethe quantity required to convert the aminodiphenylamine intoWillstatter and Moore’s blue imide. On adding the iron salt, avoluminous indigo-blue precipitate of the imide was first produced,which, after about twelve to twenty-four hours, slowly lost its bluecolour and became green, while the excess of peroxide disappearedand an odour of p-benzoquinone was apparent.The mixture waswarmed on the water-bath, and the precipitate collected, washed,and basified with ammonia.When prepared by either of these methods, the emeraldine basALLIED COMPOUNDS. PART I. 2393forms an indigo-blue powder, which, when purified by the aceticacid method, has a bronzy lustre. When dried at a low temperatureit retains a remarkably large amount of water (about 30 per cent.).It is insoluble in alcohol, benzene, chloroform, etc., but dissolvesreadily in cold pyridine, giving a bright blue solution. This solutionis, however, very unstable, for in a short time the greater part ofthe product separates out again a.s a colloidal precipitate.Thisprecipitate consists of a condensation product of quite differentproperties to the original emeraldine. In concentrated sulphuricacid, emeraldine dissolves with a reddish-violet colour, and onaddition of water a bright green precipitate of the sulphate isobtained. Towards acetic and formic acids the behaviour ofemeraldine and nigraniline is very remarkable. These bases areinsoluble in glacial acetic acid or in concentrated formic acid, andare also insoluble in these acids when fairly dilute, but in acids ofmedium concentration, that is, in acetic acid of about 80 per cent. orin formic acid of about 60 per cent., they dissolve readily. Thesolutions obtained with emeraldine are yellowish-green, and givea green precipitate on the addition of mineral acids or salts.Bymeans of such a solution, the various stages of oxidation can bevery effectively demonstrated, for on addition of a very dilutesolution of chromic acid the green colour of the solution firstchanges to pure blue (nigraniline), and then, as more oxidisingagent is added, to violet (pernigraniline), finally giving a violetprecipitate (pernigraniline chromate). I f to the violet solution ofthe pernigraniline a very weak solution of sodium hydrogen sulphiteis added, these colour changes occur in the opposite direction,namely, from violet to blue, and from blue to green. Strongerreducing agents, such as phenylhydrazine, sodium hyposulphite, ortitanium trichloride, convert emeraldine into leucoemeraldine.I n order to determine the quantity of hydrogen required forconversion of emeraldine into leucoemeraldine, the acetic acidsolution was titrated with titanium trichloride according to Enecht’smethod, the analysis being carried out as follows.One gram ofemeraldine in fine powder is weighed into a 250 C.C. flask containing50 C.C. of water, and well shaken t o prevent any of the powderagglomerating into lumps. Glacial acetic acid is then added untilthe flask is about threequarters full, the contents well shaken, andheated on the water-bath for fifteen minutes t o about 90° toensure conversion of all nigraniline present into emeraldine. Thosolution is then cooled, and made up to the mark with glacial aceticacid.For each titration, 25 C.C. of this solution (=0-1 gram ofsubstance) are transferred, by means of a pipette, to a conical flask,and mixed with 25 C.C. of water and a measured excess of titaniumVOL. XCVII. 7 2394 GREEN AND WOODHEAD : ANILINE-BLACK ANDtrichloride, the strength of which is re-determined each day. Themixture is kept in the cold for ten to fifteen minutes, air beingexcluded by a slow stream of carbon dioxide. At the end of thistime the solution is quickly filtered from the precipitated leuceemeraldine, employing a funnel and filter paper enclosed in a vesselfilled with carbon dioxide. An aliquot portion of the whole (50 c.c.)is then transferred to another flask also containing carbon dioxide,and at once titrated with a standard ferric alum solution, employingammonium thiocyanate as indicator.I n calculating the results, thepercentage of water, chlorine, and ash is allowed for, and a furthersmall correction, determined by parallel blank experiments madeunder exactly the same conditions, is introduced for the loss oftitanium trichloride oxidised by air during the operation. The firstpreparation analysed (obtained by method I) contained 31.9 percent. of water, 1-1 per cent. of chlorine, and 0.1 per cent. of ash.The following results were obtained :VOl. GfTiCI,No. ofexperinienrun in,.t. C.C.1 252 253 254 255 256 257 258 25Vol. ofTiC1,unoxidised,13-7014-1514-1513'2313.6513'5513-4713-47c. c.Vol.ofTiUI,oxidisedby air,1.770.920.921-301'341 '331 *291 -29C . C.Hydrogenvalue of1 litreTiCI,,gram.0.03740'03660.03660-03580.03580.03580 03580.0358Mean .........Percentageof hydrogenon puredryemeraldhe.0.5330.5430.5430.5800.5360-5420.5450.5450.543--A second series of estimations was made with a larger excess oftitanium trichloride and another preparation of emeraldine con-taining 30'65 per cent. of water, 1.0 per cent. of chlorine, and 0.1per cent,. of ash. Using 0.1 gram for each titration, the followingresults were obtained :Vol. of Vol. ofTiCI, TiC1, un-No. of run ill, oxidised,experinleu t. c. c. c. c.1 50 40.692 50 4 0 5 93 50 40'804 50 40'69Vol.ofTiCI,oxidisedby air,0-870.870.880'87c. c.Hydrogen Percentagevalue of of hydrogen1 litre on puregra 111. emeraldine.0.0442 0.5470'0442 05530'0442 05400'0442 0.547TiCI,, dryMean ......... 0.547Figures of the same order were also obtained by direct titrationof the acetic acid solution with titanium trichloride, although, owinALLIED COMPOUNDS. PART I, 2395to the uncertain end-point, the results were not as trustworthy asthose obtained by the indirect method.The mean value of the two series of determinations was 0.545gram of hydrogen for 100 grams of pure dry emeraldine.A diquinonoid compound of the formula :NH N kI N N/\/\/\ /\/\/’\ /\/\/’\ /\/\/\I I I I I I I I I I 1 1 I I I I:NH\/ \/\dHV ‘\A/<\/ \/>/\/ \/would require 0.555 per cent.of hydrogen for complete reduction tothe leuco-compound.I n order to estimate the, quantity of oxygen consumed in theconversion of emeraldine into nigraniline, two methods have beenadopted. The first consists in titrating an acetic acid solution ofemeraldine with a standard solution of chromic acid until the pureblue colour of the nigraniline is reached. The second consists inseparately titrating emeraldine and nigraniline until the violetpernigraniline chromate is completely precipitated. Deduction ofthe quantity of chromic acid required to reach this point fornigraniline from the quantity required to reach the same point foremeraldine gives the quantity consumed in oxidising emeraldine intonigraniline. Owing to the more definite end-point, the lattermethod is the more trustworthy.I.Twenty-five C.C. of emeraldine solution, containing 0.1 gram ofsubstance dissolved in 80 per cent. acetic acid, were diluted with 25C.C. of water, and titrated with a solution of chromic acid containing3.52 grams of chromium trioxide per litre (equal to 0.845 gram ofoxygen per litre). The emeraldine employed contained 31.9 percent. of water, 1.1 per cent. of chlorine, and 0.1 per cent. of ash and1.5 C.C. of chromic acid (several experiments) were required to givea pure blue colour. Correcting for contents of water, chlorine, andash, this is equivalent to a consumption of 1.9 grams of oxygenper 100 grams of pure dry emeraldine for oxidation to nigraniline.11. (a) Twenty-five C.C.of emeraldine solution, containing 0.1 gramof substance dissolved in 80 per cent. acetic acid, were diluted with25 C.C. of water, and titrated with a solution of chromic acid con-taining 0.704 gram of chromium trioxide per litre (equal to 0.169gram of oxygen per litre) until the precipitation of the violetpernigraniline chromate was complete, and no further change ofcolour took place. The emeraldine employed contained 30-65 percent. of water, 1 per cent. of chlorine, and 0.1 per cent, of ash.7 ~ 2396 GREEN AND WOODHEAD : ANILINE-BLACK ANDWeight of Vol. of ClO,No. of el ileraldiii e, required,experiment. gram. c. c .1 0 '1 24 -52 0.1 25 -03 0.1 25 *O4 0-1 24.5Mean,. . , , * . . IPerceiit:Lgo ofoxygen 011pnre dryemeraldine.6.076 '196-196.07,.6'13-( b ) A weighed quantity of nigraniline (preparation see later) wasadded in a state of fine powder to 5 C.C. of water. The whole wascooled in ice, 20 C.C. of glacial acetic acid added, the mixture shakenuntil dissolved, and then a t once titraked with chromic acid asabove. The nigraniline employed contained 11.28 per cent. ofwater, 1.12 per cent. of chlorine, and 1.3 per cent. of ash:Weight of Vol. of CrO,No. of nigraniline, required,1 0.0950 19-52 0.0983 20'03 0'1257 25 -04 0.1017 21.0cxperimen t. gram. c. c.Mean ......Percentage ofoxygen onpure drynigran iliiie.4'023.983'894 '04,.. 3.98-Deducting 3-98 from 6-13 gives 2.15 as t.he percentage of oxygenrequired to oxidise pure dry emeraldine into nigraniline.Ifemeraldine has the above formula, it would require, theoretically,2-20 per cent. of oxygen for the removal of two hydrogen atoms,that is, to introduce one quinonoid group.Nigraniline.The best method for the preparation of nigraniline in substancewas found to be the oxidation of emeraldine base (or the mixtureof emeraldine and nigraniline obtained by the chlorate oxidation),using an excess of hydrogen peroxide in an ammoniacal solution.For instance, the precipitate obtained by oxidising 40 grams ofaniline hydrochloride and 18.6 C.C. of hydrochloric acid with 16.8grams of sodium chlorate in presence of vanadium, as alreadydescribed, is basified with ammonia, and the washed product,without being dried, is evenly suspended in 6 litres of water, towhich 400 C.C.of hydrogen peroxide (3 per cent.) and 40 C.C. ofconcentrated ammonia are added. After keeping overnight, theprecipitate is collected, washed well, and dried at 35O. The productcontained 11.28 per cent. of water, 1.12 per cent. of chlorine, and1.30 per cent. of ashALLIED COMPOUNDS. PART I. 2397Nigraniline base forms a bluish-black powder with a bronzy lustre.Like emeraldine, it is insoluble in most solvents, but dissolves incold pyridine with a bright blue colour. The salts are blue, notdark green as stated in the literature. This error arises from thefact that nigraniline salts are very unstable, and both in substanceand on the fibre are readily converted into salts of emeraldine. Thechange takes place slowly in the cold, but more rapidly on heating,and is accompanied by the production of p-benzoquinone.Onepart of the nigraniline is oxidised to p-benzoquinone, whilst anotherpart is reduced to emeraldine, a fact which affords an explanationof the well-known “greening” of certain blacks on the fibre whenexposed to an acid atmosphere. Similarly, when nigraniline isdissolved in concentrated sulphuric acid, it gives a violet solutionof rather bluer shade than t>hat of emeraldine, but on pouring intowater, decomposition occurs, and a bright green precipitate ofemeraldine sulphate is produced. Nigraniline dissolves readily andcompletely in cold 80 per cent. acetic acid or in 60 per cent.formicacid, giving pure deep blue solutions. These solutions, on warming,quickly change in colour t o the green of the emeraldine salt. I ncontrast to the instability of the salts, nigraniline base is quitestable.In performing the quantitative reduction of nigraniline, it isessential for the above reasons to avoid all heating in making thesolution, and to effect the reduction as rapidly its possible. Theoperation is therefore carried out as follows. A weighed quantity ofnigraniline (about 0.1 gram), which must be very finely powderedto ensure quick and complete solution, is suspended in 5 C.C. ofwater contained in a small flask. The flask is then cooled in icefor ten minutes, 20 C.C. of glacial acetic acid added, and the mixtureshaken for half a minute, by which time the substance should havedissolved completely.Before the addition of the acetic acid, theair in the flask is expelled by carbon dioxide. The titanium tri-chloride solution is then added, and the titration effected in thesame manner as with emeraldine:Weigli t ofnigranilineNo. of taken,experiment. gram.1 0.10092 0.06733 0-10894 0.13205 0.11986 0’1108Vol. ofTiC1, run in(1 litre=0.0307 gramof hydrogen),40404050505 0c. c.Vol. ofTiCI, leftunoxidised,17.323.8515’6220.4723-3824.35c. c.Vol. ofTiCl,oxidisedby air,0.871.200-780.630 *720 *75C.C.Percentage ofhydrogen onpure drynigraniline.0.7710,7910.7720.7810.7700’801Mean ...... ... 0.782398 GREEN AND WOODHEAD : ANILINE-BLACK ANDAnothersolution (1results :No. ofexperiment.78910series of titrations made with a stronger titaniumlitre = 0.0442 gram of hydrogen) gave the followingWeight ofnigranilinetaken,gram.0‘13860*09000*10900.1035VOl. ofTiCI, run in(1 litre =0.0307 grainof hydrogen),50505050c. c.Vol. ofTiCl, leftunoxidised,27 -9835-0632.1032.95e. c.Vol. ofTiCl,oxiciisedby air,0.510.630.580’60c. c.Percentage ofhydrogen onpure drynigraniline.0,7970.8160.8160’816Mean.. .... ... 0.811A triquinonoid compound of the formula:NH N N N/\/ \/\ /\/\/\ /\/\/\ /\,A/\1 1 1 1 1 1 ! 1 1 l 1 1 1 I I.Nwould require 0.835 per cent.of hydrogen for complete reductiont o leucoemeraldine. This formula is also supported by the oxidationnumbers given under emeraldine.Although the above formula is the same as that given byWillstatter and Dorogi to the preparation which they term “tri-quinonoid aniline-black,” yet the compound described and analysedby them can scarcely be identical with nigraniline, for the propertiesdo not correspond. If these authors originally had nigraniline inhand, it must have suffered conversion into emeraldine, and probablyinto further decomposition products by the process of purificationemployed.Pe rniqranitin e.N N N NWhen a, solution of emeraIdine or nigraniline in acetic or formicacid is treated with an excess of a powerful oxidising agent, suchas chromic acid or ammonium persulphate, the oxidation proceedsbeyond the nigraniline stage, giving rise to a violet precipitate,which, on basifying with ammonia, yields a purple-brown compound,‘ I pernigraniline.” This substance is exceedingly unstable, decom-posing slowly on drying, or even if kept in the paste form, withreproduction of nigraniline and formation of other products.Thisdecomposition occurs still more rapidly in the presence of acids,following a, similar course to nigraniline, which, together withp-benzoquinone, is first formed. The change is brought about bya few drops of dilute hydrochloric acid, and also more slowly byacetic acid. Reducing agentfi, if applied at once, convert perALLIED COMPOUNDS. PART I. 2399nigraniline first into nigraniline, then into emeraldine, and finallyinto leucoemeraldine. The base is soluble in pyridine, with a purplecolour, and apparently undergoes decomposition in this solvent inthe same manner as do emeraldine and nigraniline.I n con-centrated sulphuric acid, it dissolves with a bluish-violet colour.On pouring this solution into water, a green precipitate of emeraldinesulphate is produced.On account of its instability, pernigraniline cannot be obtainedpure in the dry state; an almost complete reversion to nigranilineoccurs during drying, An attempt was therefore made to submitit, without drying, to analysis by reduction, employing a paste whichcontained 8-45 per cent. of dry product. This was prepared asfollows.Five grams of tho mixture of emeraldine and nigranilinebase obtained by the chlornte method were dissolved in 500 C.C. of80 per cent. acetic acid. To the icecold solution was added 5 gramsof ammonium persulphate dissolved in a little water, when a violetprecipitate at once separated. The whole was then immediatelystirred into an excess of dilute ammonia mixed with crushed ice,the temperature being kept as low as possible, After adding alittle salt, the precipitate was collected, washed with several litresof water, and brought to a uniform consistency, in which the per-centage of water was estimated. The following results were obtainedon analysis:Weight ofpernipanilinepaste (8'45No. of per cent.)experiment. grams.1 0.95652 1-17823 0'89004 1.8010Vol. of TiCI,run in (1 litre= 0.0507 gramof hydrogen),50505050c. c.Vol.ofTiCl, leftunoxidised,34'731 -836 '424.9c. c.VOl. ofTiCI,oxidisedby air,0-280-250.290 '20c. c.Percentageo f hydrogenon dry per-nigraniline.0.9490.9140.89607330A tetraquinonoid compound of the above constitution wouldrequire for reduction to leucoemeraldine 1.1 1 per cent. of hydrogen.It will therefore be seen that, whilst the first titration gives a valueapproaching that required by this formula, there is a steadydiminution in the consumption of hydrogen in the later analyses.The last titration, which was made after the paste had been kepta day, gives a hydrogen value almost corresponding with that ofnigraniline (theory, 0.835 per cent.).The above formula for pernigraniline is also supported by thefigures given on p.2396 for the consumption of chromic acid requiredto oxidise emeraldine and nigraniline to pernigraniline chromate.Thus, calculating the whole chromic acid as oxygen, the results are :C43H34N8 + $30, requires, Oxygen consumed,6.13per cent. per cent.From emeraldine.. . , . . . , , 5 -96 ,, nigraniliiie .. . . . . 3-98 3'72400 GREEN AND WOODIIEAD : ANILINE-BLACK ANDIt will be seen that the above formula for pernigraniline is thesame as tbat assigned by Willstiitter and Dorogi to the preparationswhich they call “ tetraquinonoid . aniline-black.” The greatinstability of pernigraniline is, however, entirely inconsistent withthe assumption that these products are identical, since the treatmentto which Willstatter and Dorogi’s preparations were subjected wouldhave completely decomposed pernigraniline, and even the dryingalone, without t,reatment with acid, would have converted it intonigraniline.L euco emerddine.NH NH NH NHA/\/\ /\/\/\ AA/\ /\/\/\1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1\/ \/>/\/ \A*&/ \/\NJH\/ \/*l1?This product is readily prepared by reducing either emeraldineor nigraniline with a strong reducing agent.For instance, themixture of emeraldine and nigraniline bases obtained by the chlorateoxidation was moistened with alcohol in a mortar, and then groundto a paste with a concentrated solution of sodium hyposulphite anda little ammonia.The precipitate was collected, washed, and driedin a vacuum.A better method consists in moistening the dry base with puredry ether, and grinding the paste with an equal weight of phenyl-hydrazine. It is then thrown on a filter, and washed with dryether until the excess of phenylhydrazine is removed, after whichthe product is dried quickly on a porous plate.Leucoemeraldine forms a pale brown, amorphous powder, probablycolourless when pure, which does not melt below 350O. It is fairlystable when dry, but when exposed to air in a damp st-ate it becomesblue. It is insoluble in most solvenk, but dissolves to a slightextent in pyridine. In 80 per cent. acetic acid or in 60 per cent.formic acid, it is sparingly soluble.The constitution assigned to leucoemeraldine above is supportedby the fact that four atoms of hydrogen are required for itsformation from emeraldine, and six atoms for its formation fromnigraniline.Willstatter and Dorogi’s Blacks.I n order to ascertain how far the products examined by theseauthors, and termed “ triquinonoid aniline-black ” and “ tetra-quinonoid aniline-black,” compare in properties with the foregoingcompounds, we have prepared them by following exactly the pre-scriptions given.The properties of the products we obtained aregiven in the following tableALLIED COMPOUNDS. PART I. 2401Prodnc t.I’ersulpliate Black.(W. & D.)Richroniate Black.(W. & D.)Chlorate Black :triquinonoid, 6hours. (W. & D.)triquinonoid, 23hours.(W. & D.)tetraquinonoid, 6hours. (W. & D. )Chlordte Black :tetraquinonoid,22 hours.(We& D.)Clilorate Black :Chlorate Black :80 per cent. aceticacid.Considerable por-tion soluble withb r i g h t bluish-green colonr.As above.Small part solublewithdullgreenishcolour.Trace soluble withd u l l g r e e n i s hcolour.Small part solublewith dull greenishcolour.Sparingly solublew i t h greeniskcolour.60 Per cent. formic !acid. Ipyridine,Partly soluble with I Considerable por-b r i g h t green tion soluble withcolour. ~ deep blue colour.1As above. i As above.Nearly insoluble. Trace only solublewith pale blue 1 colour.Insoluble.Insoluble.Very sparinglysoluble.Very s p a r i n g l ysoluble with palebluc colonr.As above.As above,It will thus be seen that these products differ entirely from theemeraldine, nigraniline, and pernigraniline described above.Theyappear to be mixtures contqining emeraldine, together with furthercondensation products. Three of them were submitted to successiveextractions with cold 80 per cent. acetic acid until nothing furtherdissolved.Chlorate Black :The following were the results obtained :Persulpliate Black Bichroinate Black triquinonoid(W. & D.), (W. & D.), (W. & D.),per cent. per cent. per cent.Soluble poi tion . . . . , , 51-5 60’0 80.0Insolnble portion . . . 48.5 40’0 20 .oOxidation of o-Toluidine.It has long been known to technologists that o-toluidine, whenoxidised on the fibre, gives rise to a black which is not so brilliantas aniline-black, but which has less tendency to ((green.” Noattempt has apparently been made to prepare this dye or its inter-mediate compounds in substance.We have found that under the same conditions its employed foraniline the oxidation proceeds in an analogous manner, givingcorresponding products.It appears, however, that the pnmaryoxidation products are rather less stable than in the aniline series2402 GREEX AND WOODHEAD : ANlLlNE-BLACK ANDbeing more prone to undergo polymerisation, and that the higherquinonoid products are less easily formed, and more readily revertto the lower. The best results were obtained by conducting theoxidation without any excess of mineral acid.Thus, 33 grams ofo-toluidine and 34 grams of hydrochloric acid (33 per cent.) weredissolved in 700 C.C. of water, with the addition of 16.8 grams ofsodium chlorate and 2 drops of syrupy vanadium chloride. Afterbeing kept for three days at the ordinary temperature, the greenish-blue precipitate was collected, washed with water, basified withammonia, and then repeatedly extracted with 90 per cent. alcoholin order to remove a soluble by-product ( ? homologue of Willstatter'sblue imide). It was then dried a t 30-35O. The product is aviolet-blue powder of indiplike appearance. It is insoluble inmost solvents, but dissolves readily in pyridine with a blue colour,and in 80 per cent. acetic acid or 60 per cent. formic acid with adull yellowish-green colour.It contains 4.6 per cent. of waterand 2.0 per cent. of chlorine.The analysis by reduction wils effected in the same manner asemployed for emeraldine.Vol. of TiCl, HydrogenVol. of TiCI, Vol. of TiCl, oxidised by value of 1 PercentageNo. of run in, unoxidised, air, litre TiCl,, on pure dryexperimcn t. c. c. c. c. c. c. gram. substance.1 50 45'43 0.36 0.0506 02282 50 45-15 0.36 0-0506 0.2433 50 44'71 0.36 0-0506 0'2674 50 44'89 0.36 0.0506 0'2575 50 45'88 0-37 0.0506 0-20350 45'25 0.36 0.0506 0'238 60'239-Mean.. . . . . . . .A monoquinonoid compound of t,he constitution :Me N H Me N H Me NH Me N/\/\A /\A/\ /v\/\ /\A/\I I I I I I I I I I I I I I I I.NH.\/ \&y \M;\N&-\/ \M</<\/ \/-Alewould require 0.24 per cent.of hydrogen for reduction to theleuco-compound. It therefore appears that the product of theoxidation of o-toluidine is the protoemeraldine of this series.Another preparation in which an excess of acid was used in theoxidattion gave as the average consumption of hydrogen for reduction0.360 per cent. This preparation was therefore apparently amixture of the t oh-protoemeraldine with t olu-emeraldine.Attempts to oxidise tolu-protoemeraldine into a higher oxidationstage by means of hydrogen peroxide and ammonia, employing thesame conditions as those used for nigraniline, gave a negative result.The product still dissolved in acetic acid with st green colour, anALLIED COMPOUNDS. PART I. 2403afforded the same reduction figures as before. On the other hand,on a.ddition of chromic acid or persulphate t o the acetic acid solution,the colour first becomes blue and then violet, as in the aniline series.It therefore appears that the formation of the tolu-nigraniline doesnot take place with the same facility as with the lower homologue,a conclusion which is supported by the fact that no tolu-nigranilinewas ever produced in our experiments with the chlorate andvanadium oxidation.Oxidation of Other Amines.The oxidation of various primary amines was studied under thesame conditions as employed in the preparation of emeraldine.o-Chloroaniline gave emeraldine-like products ; m-chloroaniline gavenone. o-Anisidine underwent oxidation in a different direction,apparently through elimination of the methyl groups. Dimethyl-aniline remained unattacked.Con clusio?ts.1. There are four quinonoid stages derived from the parent com-pound leucoemeraldine.2. The minimum molecular weights of these primary oxidationproduct8 of aniline are in accordance with an eight-nucleal structure.3. The conversion of emeraldine into nigraniline consumes oneatom of oxygen.4. The conversion of emeraldine into pernigraniline consumes twoatoms of oxygen.5. The conversion of nigraniline into pernigraniline consumes oneatom of oxygen.6. The reduction of emeraldine to leucoemeraldine consumes fouratoms of hydrogen.7. The reduction of nigraniline to leucoemeraldine consumes sixatoms of hydrogen.8. The reduction of pernigraniline to leucoemeraldine consumeseight atoms of hydrogen.9. The reduction of tolu-protoemeraldine consumes two atoms ofhydrogen.10. None of these products are properly entitled to be consideredas aniline-black, but are intermediate products in the formationof the latter.DEPARTMENT OF TINCTORIAL CHEMISTRY,UNIVERSITY OF LEEDS

ISSN:0368-1645    

DOI:10.1039/CT9109702388

出版商:RSC    

年代:1910

数据来源: RSC

摘要:

2404 CROSS, BEVAN, AND BACON : CHLOROAMINECCXLIV.-Chloiaoa~~i.ILe Beccctioias. Mcthyleae-chloroami.iLe."By CHARLES FREDERICK CROSS, EDWARD JOHN BEVAN, andWILLIAM BACON.CRLOROAMINE, NH,CI, although not yet isolated, has been closelycharacterised by its reactions in solution. Raschig (Bey., 1907, 40,4586) has verified the above formula by the synthesis of hydrazineaccording to the equation :NH,Cl+ NH, = H,N*NH,,HCl.I n oxidising actions, the chloroamine chlorine reacts as the chlorineof hypochlorites, thus :from which, and in view of its formation by interaction of hypo-chlorites and ammonium salts, it might be formulated as NH,OCl.From a general view of its oxidising reactions, however, these arefound in many and typical cases to be sharply differentiated from thoseof the hypochlorites, and hence its formation from hypochlorites israther represented by the equation :NH,C1 -I- 2HI = NH,Cl+ I,,NH, + M*OCl= NH,Cl+ M*OH.It may be inferred from Rnschig's investigations that such reactionswould be a general characteristic of amino-compounds, and me havestudied certain of these in relation t o their conversion intochloroamines.As a result, we have been able to characterise the compoundsobtained from proteins by the action of chlorine as chloroamines(Cross, Bevan, and Briggs, J.Xoc. Chem. Ind., 1908, 27, 260).Such compounds have been known since 1840 (Mulder, Beraelius'Jahyesber, IS, 734), and their formation has been made the bmis ofquantitative analytical methods (Ridenl and Stewart, Analyst, 1897,22, 228), depending on the separation of these derivatives, which areinsoluble in water, followed by nitrogen estimations in the precipitatedcompounds. These methods we find are much simplified by estimationsof chloroamine chlorine according to the well-known chlorimetricmet hods.We have described such methods in detail as applicable to theestimation of gelatin, and we have also applied similar reactions tothe elucidation of ind'ustrial processes which are attended by theformation of chloroamines, notably the bleachiug of flax textilesI n the case of gelatin it is noteworthy that the chloroaminea This name is retained pending the final settlement of the constitution of the(ZOC.cit.).compound, in order to indicate its relation to chloroamineREACTIONS. METHYLENECHLOROAMIKE.2405derivative is of constant composition, the chloroamine chlorine ( = (21,)representing 18 3 per cent. of origiual gelatin, and after dehydrationis stable in the air.JIeth yknechloroccmine.The typical reactions of chloroamine, especially with aromatic aminesand phenols, have further been elucidated by Raschig (Chem. Zeit.,1907, 31, 126; Zeihch. angew. Chem., 1907, 20, 2065).I n extending these investigations, we have observed a reaction OFspecial interest which we will briefly describe, as it involves a newchloroamine, readily obtainable in crystalline form.Formaldehyde and chloroamine in aqueous solution react according tothe equation :CH,O + H,NCl = UH,:NCl+ H,O,t-he resulting methylenechloroamine separates in well-formed crystnls,and on recrystallisation from chloroform, in which it is easily soluble, itis obtained in needles of 10 to 15 mm. in length.To prepare this corn,pound, approximately semi-normal solutions of hgpochlorites (C1=1.8 grams per 100 c.c.) are treated with ammonium chloride, andformaldehyde solution added in the cold, The proportions are takensomewhat in excess of the calculated. On keeping at, or under, 1 5 O ,the solution becomes milky, and the compound then crystallises. Itis obtained as a mass of brilliant, felted needles. The yields underthese conditions are 30 to 40 per cent, of the calculated,For analysis, the substance is dissolved in chloroform, the solutionbeing left for some hours in contact with calcium chloride, andpoured off through a dry filter, when, after some time, the substancecrystallises out.Many preparations have been analysed, and the numbers are i n closeaccordance wlth the formula CH,NCl.The following results are typical :Total c h l o k e , by digestion with sodium sulphite and precipitation0.1255 gave 0*2815 AgC1.6 ‘ Aciive ch20iiq’’ by digestion with potassium iodide solution and013124 liberated 1 = 99.8 C.C.N/lO-thiosulphate.,?Titi-ogen, by digestion with ferrous sulphate, in presence ofsulphurous acid, and distillation from alkalis ; the nitrogen beingobtained as ammonia :as silver chloride :titration of the liberated iodine :0.1135 gave NH,= 18-2 C.C. N/lO-HCl.Found, Total C1= 55.4 ; “ Active ’’ C1= 56.7 x 2 ; N = 22.4.CH,NC1 requires Total C1= 55.9 ; “ Active ” C1= 55.9 x 2 ;N=22*05 per cent.VOL, XCVll.7 S2406 CHLOROAMINE REACTIONS. METHYLENECELOROAMIKE.Molecular - weight determinations even by uryoscopic methodspresent difficulties, due to the instability and reactivity of thecompound, but the following numbers calculated from the depressionof the freezing point of benzene were obtained :Found, M.W.= 133.0, 132.7, 131.7.SCH,NCl requires B1.W. = 127.Our incidental obeervations indicate a change of solubility inbenzene from 2 7 t o 1-5 per 100 C.C. at 5 O , and poiyinerisation probablyhas to be taken into account. This point mill be resolved by furtherinvestigatioii.~eth~Ze.nechEoro~na~~~ is soluble in 20 to 30 parts of ether at theordinary temperature, and similarly in benzene, as indicated above ; itis only sparingly soluble i n paraffinoid hydrocarbons.It decomposes spontaneously in ordinary air, and when heated at60-60" it decomposes explosively, leaving n residue of ammoniumchloride.As shown by the analytical results, it may be quantitatively bydro-lysed and reduced, ammonia and formaldehyde being regenerated, andby certain decompositions it yields hydrocyanic acid as a main productThe investigation is being continued.4, NEW COURT:LONDON. W.C

ISSN:0368-1645    

DOI:10.1039/CT9109702404

出版商:RSC    

年代:1910

数据来源: RSC