摘要:

AMMONIUM BED OTHER IMIDOSULPHITES. 1099 CXVIIL- Ammonium and other Imidosulphites. By EDWARD DIVERS and MASATAKA OGAWA. THE fact of the existence of ammonium imidosulphite as a product of the decomposition of the amidosulphite by very gentle heating, 2NH,*S0,*NH4 = NH, + NH(SO,NH,),, was brought before a meeting of the Society last session (Proc., 1900, 16, 113). Thepresent paper consists of a fuller account of this salt and other imidosulphites than could then be given. Ammonium amidosulphite, from which the imide salt is derived (Trans., 1900, 77, 327), is readily formed by the unioii of sulphur dioxide and ammonia, but is so unstable as to be largely decomposed by the unavoidable heating it suffers when these gases come together, unless cooled ether be used as their solvent.On keeping the dry salt a t a temperature of about 3 5 O , its decomposition goes on, and ammonia escapes for some hours. There is left a mottled orange mass of waxy consistence already described in the earlier paper (Zoc. cit., p. 333), which is difficult to attack with solvents other than water, because i t adheres very firmly to the vessel and must not be exposed to the air during treatment. By protracted digestion with successive portions of 9 0 per cent. spirit, aided by scraping with a pointed glass rod and vigorous shaking, it can, however, be nearly all dissolved up, although only very sparingly soluble. The first portions of the solution are coloured, and contain a salt, the presence of which interferes with the prepara- tion of the imidosulphite from them The later colourless extracts yield the imidosulphite when they are evaporated in the vacuum desic-1100 DIVERS AND OCtAWA: cator, but not quite pure.Much better results are got by beginning the treatment with warm 95 per cent. spirit, used in successive por- tions, until the residue is a colourlees powder: and only then resorting to the 90 per cent. spirit and carrying on the digestion at about 50'. The solution thus obtained deposits almost pure imidosulphite as it cools, and the mother liquor can be used with advantage again and again to dissolve out more of the salt, although in that case the crys- tals which separate are somewhat impure. These, can be purified by washing with absolute alcohol containing much ammonia to dissolve out the foreign salt (more soluble in presence of ammonia), and then dissolving up in warm 90 per cent. spirit and recrystallising.The original mother liquor yields more imidosulphite, but impure, when it is either artificially cooled (as by ice and salt) or is evaporated in the desiccator. This impure salt can be purified in the may just described. All the ammonium irnidosulphite is finally washed with ammoniacal alcohol, drained on a porous tile under close cover, and dried in a desiccator over potash. The quantity of pure salt actually obtained in this way approaches that of a fourth only of the weight of decomposed amidosulphite taken, but the total production of imidosulphite will no doubt prove to be very much greater. AnccZysis.-The salt,, 0.4240 gram, distilled with potash, yielded ammonia, 0.0817 gram, and then, after heating for some time in a tube with hydrochloric acid under pressure and again distilling with potash, 0.03755 gram more ammonia.Simple distillation with potash of 0.4912 gram of another portion of salt gave 0.0939 gram of am- monia, and then, after oxidation by means of bromine followed by hydrochloric acid and potassium chlorate, 1 *2886 grams of barium sulphate. The calculated and found percentages are : Ammonia Imide Total nitrogen. nitrogen. nitrogen. Sulphur. NH(S02NH,), ... 15.64 7.82 23.46 35.75 Found 7-29 23.15 - ............ 15.86 .............. 15.74 - - 36.02 It will be seen that the analysis establishes, not -only the composi- tion of the salt t o be 3NH3,2S0,, but also its imide constitution.Properties.-It occurs in minute, micaceous needles. Heated very slowly in a tube, it soon begins to decompose into volatile substances and a residue of sulphur, ammonium snlphate, aud the 9 normal ammonium imidosulphate, [NH(S03NH,),]. Even when the tempera- ture is raised t o 150°, no fusion takes place. The sublimates which form during the heating begin t o appear at about SOo, and consist apparently of ammonium pyrosulphite, [(NH,)2S,0,], and the unchangedAMMONIUM ANb OTHER IMIDOSULPHITES. 1101 imidosulphite, [(NH,)2S20,NH]. The salt is insoluble in alcohol, and in this respect is unlike ammonium amidosulphite, which is very soluble as ethyl ammoniumsulphite and ammonia. The salt is only moderately deliquescent and, freshly prepared, is neutral to litmus." It has a mild, unpleasant, sulphurous taste, which distinguishes it from the salt occurring with it, more freely soluble than it in 95 per cent.spirit, and already referred to. It is freely soluble in water, but slowly decomposes into thiosulphate and amidosulphate. This change beginning at once, the solution gives all the reactions of n thiosulphate. It goes on also in presence of hydrochloric acid, which when hot hastens its completion. Barium thiosulphate has been prepared from the solution, and amidosulphuric acid and ammonium amidosulphate also obtained from it. Quantita- tive determinations of the sulphur, sulphur dioxide, and amidosu1phat.e formed on boiling with hydrochloric acid gave results in agreement with the following equation : 2NH(SO,NH,), + 2HCl =fz 2NH,*S03NH,+2NH,C1 + SO, + 8 in which the SO, and S represent decomposed thiosulphuric anhydride.Potassium Imidosulp?&e, --It has already been stated when detailing the analysis of the ammonium salt, that that salt yields just two- thirds of its nitrogen as ammonia when boiled with potassium hydr- oxide in aqueous solution. I n accordance with this fact, it has been found that potassium imidosulphite is obtained when, to the ammoniuni salt dissolved in 70 per cent. spirit, alcoholic potash is added until the solution just renders red litmus paper permanently blue on exposure to air. The salt soon separates as minute, micaceous crystals firmly adherent to the glass. After repeated mashing with-absolute alcohol, the salt has been found to remain alkaline to litmus, quite possibly, however, because of the presence of a trace of tripotassium salt, as happens in the case of imidosulphates. The imidosulphite unlike the corresponding potassium imidosulphate, NH(SO,IC),, is very soluble in water, and its solution gives the imidosulphite reactions of the ammonium salt.It has, too, the sulphurous taste of tbat salt'. I n the analysis, nitrogen was determined by the combustion method, sulphur by oxidation, as in the analysis of the ammonium salt, and potassium by ignition with sulphuric acid, with the following results : * As first obtained by us last year and then described, the salt had an acid re- action and was exceediugly deliquescent ; but as it showed a deficiency in ammonia (22.2 instead of 23.5 per cent.), and as its potassium derivative was not acid, we indicated our expectation that when obtained in a purer state the salt would prove to differ somewhat in properties from what we had then found' VOL, LXXIX 4 F1102 AMMONIUM AND OTHER IMIDOSULPHITES+ Potassium.Nitrogen. Sulphur. NH(SO,K), .............. 35.29 6-33 28.96 Found ..................... 35.17 6.74 28.88 - 6.93 - ,, ..................... Barium Ammonium 1midosulphite.-When the orange mass of de- composed amidosulphite is dissolved in water and mixed with baryta water in such quantity as to leave undecomposed some of the ammon- ium imidosulphite it contains, the filtered solution when concentrated in the desiccator deposits the double salt in minute, micaceous crystals. Only barium and sulphur were determined.The results agree with those calculated for Ba(S02NHS02NH,),. Barium. Sulphur. BaN4H1,S40, ........................... 29.85 2’7.89 Found .................................... 29.94 26.90 In the Proceedings (1900, 16, 104), the existence of this salt was indicated, but by mistake it had been taken to be a salt of the acid N2H,S20,, and was accordingly formulated as Ba(N,H3S,0,),,2H,0. It is soluble in water, and its solution behaves as that of an imido- sulphite, being precipitable by baryta (N,H,S,O, salts are not), and besides at once gives off ammonia when moistened with potassium or barium hydroxide solution. The treatment of the orange mass of decomposed ammonium amido- sulphite with 95 per cent. spirit as a preliminary to dissolving out the main quantity of imidosulphite with 90 per cent.spirit, yields yellow, alcoholic solutions, which on evaporation in the desiccator deposit crys- tals which are short, thick prisms almost cubicalin appearance and about 2 mm. across. They are thus quite unlike the minube, micaceous needles of ammonium imidosulphite. They are yellow, but the colour is adven- titious. They can be purified and rendered white by putting them into 95 per cent. spirit and then almost saturating this with ammonia, while the containing flask is kept immersed in cold water. I n this alcoholic ammonia, they are very sensibly soluble. The solution is decanted, and the treatment repeated until only a small quantity of white, powdery salt remains, principally imidosulphite. The solutions left for a while in open flasks, and then exposed in the desiccator over sulphuric acid, lose most of the ammonia, and the crystals reform from the solution.Washed with alcohol, they are left quite colourlessI The mother liquors evaporated in the desiccator yield crude, yellow crystals again, which can be recrystnllised from alcoholic ammonia as before. These crystals are recrystallisable without change, and have alsoMcCRAE : ETHYL SEC.OCTYL TARTRATE. 1103 been prepared by us in two successive winters, yet they give analytical results which are closely concordant with the remarkable empirical formula 4NH,,580, or N,H,,S,O,,. Nitrogen. Sulphur. N,H12S,0,0 .............................. 14.43 41.24 Found in 1900 ........................... 14.11 41-14 . . . . . . . . . . .. . . . . . . . . . . . . . . 14.36 40.02 ,, in 1901 ........................... 14.02 41.02 ........................... 14.40 These crystals are neutral and have a bitter taste, not a sulphurous one. They are freely soluble in water, and very deliquescent. The solution is unstable, and in some of its reactions greatly resembles that of ammonium imidosulphite. With potassium hydroxide, the salt evolves ammonia a t once, but analyses of potassium salts pre- pared from it in 70 per cent. alcoholic solution have given discordant results. A striking difference from an imidosulphite is that its fresh solution gives no barium precipitate, even in presence of ammonia, Also that in freshly prepared solution, i t does not decolorise iodine solution, and only slowly decolorises cold acid permanganate. It also does not give the ferric chloride coloration of a thiosulphate, which the imidosulphite does give. I t s solution becomes very acid after n time, and then smells much more strongly of suphur dioxide than a similar solution of imidosulphite. The crystalline matter having nearly the composition expressed by 9NH38SO,, mentioned in our paper on ammonium amidosulphite (Trans., 1900, 77, 334) we believe t o have been the present salt mixed with imidosulphite and amido- sulphate. On a future occasion, me hope to be in a position to report upon the constitution of the substance me have here described. ? I 9 , 29 - 7 )

ISSN:0368-1645    

DOI:10.1039/CT9017901099

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

McCRAE : ETHYL SEC.OCTYL TARTRATE. 1103 CXIX.-Ethyl see. Octyl Tarti-ate and its Di7,cnqd ccnd Diacetyl Derivutives. By JOHN MCCRAE. DURING the course of an investigation of the monoacyl derivatives of tartaric esters (Frankland and McCrae, Trans., 1898, 73, 307), it was found that, no matter how large an excess of methyl tartrate mas taken, the action of an acid chloride on i t always led to the formation of a very large proportion of the diacyl compound. With diethyl tartrate, however, it was possible by using an excess of the ester to prevent the formation of the diacyl derivative, and so obtain the monoacyl com- pound. In order to ascertain whether i t would be easily possible to 4 ~ 21104 MCCRAE: ETHYL SEC.OCTYL TARTRATE AND ITS prepare monoacyl derivatives of a tartaric ester containing an alkyl group high in the series, the following investigation was undertaken.It was originally intended to prepare dioctyl tartrate and investigate the action of acid chlorides on it, but early in the course of the work an easy method of obtaining ethyl octyl tartrate was discovered, and, so far, only this and its diacyl products have been examined. The work is being carried further, in order to realise the original intention. The results obtained do not indicate that the introduction of the octyl group in place of the ethyl exerts any retarding influence on the production of diacyl derivatives. For the purpose of obtaining a tartaric ester with an alkyl group of high molecular weight, the most suitable alcohol to use appeared to be octyl alcohol.sec.Octy1 alcohol (methyl-n-hexylcarbinol) is a commercial article, and was adopted in the experiments. When the work mas started, the results of Marckwald and McKenzie (Be?.., 1901, 34,469) had not been published, and it was believed that this alcohol was a homogeneous material. Marckwald and McKenzie have shown that the substance is not pure, but consists of a mixture of a l~vorotatory and an inactive compound. Until the active component present in the octyl aIcohol is more definitely characterised, it would be superfluous t o enter into a discussion of the possible isomerides which may be formed from a combination of the two active com- pounds. As the octyl alcohol used throughout has been OF the same compo- sition, the results obtained for the different compounds are strictly comparable with each other (Landolt, '' Optiortl Activity and Chemical Composition," p.121). EXPERIMENTAL, The octyl alcohol was obtained from Kahlbaum, and had the same rotation as that employed by Marckwald and McKenzie, namely, aD = - 17' ( I = 4) (compare also Patterson, this vol., p. 490). Fifteen grams of dried tartaric acid mere heated in a staled tube with 60 grams of distilled octyl alcohol for 3 days a t 140-160". On distilling the mixture under diminished pressure, the excess of alcohol and the water passed over a t a comparatively low temperature, and at 280-240", under 15 mm. pressure, a substance distilled which was probably dioctyl tartrate. Much decomposition took place, and the yield was very poor. On account of the insolubility of tartaric acid in octyl alcohol, the hydrochloric acid method could not be used directly.Purdie and Marshall (Trans., 1888, 53, 391) have shown that it is possible to transform one ester into another by the action of anDIBENZOYL AND DIACETYL DERIVATIVES. 1105 alcohol, and it was thought possible that such a transformation might be effected if a tartaric ester could be obtained which is soluble in octyl alcohol. Meanwhile, Patterson and Dickinson (this vol., p. 280) had proved that a reciprocal transformation of methyl and ethyl tartrates is possible with ethyl and methyl alcohols and hydrochloric acid. This method was tried, and it has been found that after a single treatment of ethyl tartrate and octyl alcohol in proper proportions mit,h hydrochloric acid, pure ethyl octyl tartrate can be produced.Etlql Octyl Tartrate. Fifty grams of diethyl tartrate are dissolved in 200 grams of octyl alcohol and the solution saturated with dry hydrochloric acid in the cold. After standing for 24 hours, the hydrochloric acid is extracted under diminished pressure and the water and ethyl alcohol, as well as the excess of octyl alcohol, are distilled off. The residue is then dis- tilled, still under diminished pressure, and the fraction passing over between 170' and 205' under 15 mm. pressure is collected. As the boiling points of diethyl and ethyl octyl tartrates do not lie far apart, it, is not easy to separate them by fractional distillation, and the dis- tillate thus obtained constantly contains some unchanged diethyl tartrate.This is best got rid of by shaking with water, which dis- solves (and hydrolyses) the ethyl compound, but does not dissolve or decompose the ethyl octyl derivative. After washing three or four times with water, t'he oil is dried as completely as possible over sul- phuric acid in a vacuum. It is then distilled under diminished pres- sure once o r twice (b. p. 200-202° under 15 mm. pressure), or until the rotation is constant. It was generally found that the rotation did not alter after two distillations. I n one preparation, some of the excess of octyl alcohol which had been distilled off was washed. with water, then redistilled, and the rotation of the fraction boiling at 178' was found to be aD= - 18' ( I = 4), as compared with a,, = - 17' found for the original alcohol.There is here no evidence of a variation in the rate of esterification of the constituents of the alcohol, but i t must be remembered that the process was carried out very differently from the method used by Marckwald and McKenzie. Various preparations of ethyl octyl tartrate gave the same rotation, namely, +5'22' in a 66.04 mm. tube a t 16'. It is a viscous, colourless oil with a decidedly rancid odour. 0.1940 gave 0.4108 CO, and 0.1548 H,O. C=57*75 ; H=9*07. 0.1195 ,, 0.253'7 CO, ,, 0.0950 H,O. C=57.90 ; H=8*83. U1,H,,06 requires C = 57.93 ; H = 8.97 per cent.1106 McCRAE : ETHYL SEC OCTYL TARTRATE AND ITS A determination of the ethoxy-group by Zeisel's method gave the 0.1490 gave 0.1039 AgI. C,H, = 8.61. C,,H260, requires C,H, = 10.00 per cent.The density and rotatory power were then determined at various following result : temperatures, and the following numbers were obtained : d 15'/4"= 1.0664. d 30°/4'= 1.0533. d 4 5 ' / 4 O = 1.0402. d 60°/40= 1.0277. d 79*8'/4'= 1*0100. Rotation of ethyl oct9Z tartrate. (Length of polarimeter tube= 66-04 mm.) Temperature. to. 16 21 -5 41.5 50 62 71 9s Observed rotation. .______ -t 5"22' 5 29 6 27 6 56 7 23 7 41 8 21 Density at to. 1.0655 1'0608 1'0433 1.0360 1.0259 1.0177 0.9937 -I- 7-63" 7 -83 9 *36 10.13 10.89 11 *43 12.72 [ M I D . + 22.13" 22.71 27.14 29'38 31-58 33-15 36 '89 Ethyl Octyl Dibenxoylturtrate. By heating together ethyl octyl tartrate and benzoyl chloride at looo, reaction took place-rather more sluggishly than with diethyl tartrate-and from the high negative rotation of the resulting pro- duct it was evident, in analogy with the high negative rotation OF diethyl dibenzoyltartrate (Frankland and Wharton, Trans., 1896, 69, 1586), that much diacyl ester was formed even when no excess of acid chloride was used. The monoacyl diethyl tartrates were obtained in the solid state, and could be separated from the diacyl derivatives by repeated crystallisation; as no acyl derivative of ethyl octyl tartrate has been obtained in the solid state, and, further, as they seem t o de- compose on heating, so that they cannot be distilled, the task of separating the mono- from the di-acyl compound seemed hopeless, and the preparation of the monoacyl derivatives was abandoned.As has been noticed, ethyl octyl dibenzoyltartrate is constantly formed when benzoyl chloride is treated with excess of ethyl octyl tartrate, and, on the other hand, the substance is not obtained pure even when a very large excess of acid chloride is used, on account of the incompleteeess of the reaction.DIBENZOYL AND DIACETPL DERIVATIVES.1107 The method which ultimately led to its isolation was as follows: One hundred grams of benzoyl chloride were heated under a reflux condenser in a water-bath, and 36 grams of ethyl octyl tartrate were slowly dropped in with continual shaking. The heating was continued for 4 days, when no more hydrochloric acid was evolved. The product was washed with water, and then with sodium car- bonate solution. Most of the benzoyl chloride was thus removed, but as this is not easily completely destroyed by water, it was found to be necessary to dissolve the oil in ether and shake the ethereal solution with sodium carbonate solution for 3 or 4 days, occasionally renewing the carbonate solution.The ethereal solution was separated, dried as oompletely as possible over ignited potassium carbonate, and, after filtering, the ether was distilled off. The last trace of ether was expelled by warming the ester in the steam-oven, then placing it in an exsiccator, and exhausting the air. A yellowish oil was thus obtained weighing 56 grams. The rotation of this at 16.5' was found t o be - 32'16' in a 66 mm. tube. The substance is easily soluble in the common organic solvents ; it is quite insoluble in water, which appears to have no appreciable hydrolysing action on it, Heated in a vacuum, it undergoes decomposition, and benzoic acid (recognised by its melting point) was found in the distillate.For its purification, precipitation by water from an alcoholic soh- tion was adopted, The oil was dissolved in hot absolute alcohol and water was added until there was just a permanent opalescence at the high temperature. It is advisable not to boil the alcoholic solution, as an interchange of alkyl groups (ethyl for octyl) might possibly then take place, although this has not been actually observed, On cooling, the solution deposited an oil, the colour of which mas not so intense as before, The oil was dissolved in ether, and the ethereal solution dried and treated as before. The rotation of the product had then risen t o -33'20' a t 15.5' in the same tube.After repeating this process of purification, the rotation had further increased to - 34'47' at 15.5', and the next purification led to the production of a substanae with rotation - 35'55' at 11' in the 66 mm. tube, after which the rotation was not sensibly altered by further treatment, The whole of the substance in the alcoholic solution was not precipitated with water, and the various residues were combined and the whole separated by the addition of more water. The oil was extracted with ether, and after drying with ignited potassium carbon- ate and evaporating off the ether, the residue had a rotation of - 29O56' in the 66 mm. tube at 14O. This oil probably consisted for the most part of ethyl octyl dibenzoyltartrate, but whether the admixture was unchanged ethyl octyl tartrate or the monobenzoyl derivative (which presumably has a higher dextrorotation than the1108 McCRAE: ETHYL SEC.OCTYL TARTRATE AND ITS simple ester-see McCrae and Patterson, Trans., 1900, 77, 1107) was not determined.Another preparation had the same rotation. The compound has only been obtained as n clear, almost colourless, viscous oil. It was suspended in boiling liquid air and a t once set to a hard, glassy mass which melted on regaining the ordinary tempera- ture. It has been kept for more than 6 months under water, but shows no sign of solidifying, 0.2542 gave 0,6245 CO, and 0,1486 H,O. The influence of temperature on the density and on the rotation has The density observations actually made were : C = 67.00 ; H= 6.50.C28H3408 requires C = 67.47 ; H = 6.83 per cent. been determined. d 19Oj4O = 1.0884. d 6 l o / 4 O = 1.0533. d 38*5'/4O = 1.0728. d 7So/4O = 1.0396. Rotation of ethyl octyl dibennxopltat-irate. (Length of polarimeter tube=66*04 mm.) Temperature. to. 0 bserved rotation. 10.8 24'2 38 47'5 54 67 79 88 99 - 35"45' - 3 5 19 - 34 50 - 3 4 20 - 3 4 2 - 3 3 31 - 32 19 - 3 1 27 - 3 0 17 Density a t 1". 1.0956 1.0845 1 '0729 1.0649 1 '0595 1'0488 1'0386 1.0313 1'0220 - 49'41" - 49-31 - 49'16 - 48.81 - 48.64 - 48'39 - 47'12 - 46 '18 - 4 4 - a c MID. - 246.0" - 245.6 - 244.8 - 243*1 - 242.2 - 234'7 - 230 '0 - 241'0 - 223 '5 Et?hyl Octyl DiacetyZtart~*ate. Acetyl chloride reacts energetically on ethyl octyl tartrate, just as i t does on diethyl tartrate. Diethyl monoacetyl tartrate is ex- tremely difficult to separate from the diacetyl derivative, in spite of the fact that the latter can easily be obtained in the solid form (McCrae and Patterson, Zoc.cit.). As ethyl octyl diacetyltartrate has not been obtained in the solid state, it appeared at the outset a hope- less task to try t o prepare the monoacetyl derivative, and consequently no attempts have been made in this direction. To obtain the diacetyl compound, 30 grams of ethyl octyl tartrate were slowly run into 50 grams of acetyl chloride heated in a water-DIBENZOYJ, AND DIACETPL DERIVATIVES. 1109 18.5 44 61 81 *5 100 bath under a refiux condenser. The heating was continued until there was no further evolution of hydrochloric acid-which may require so long as 24 hours.The resulting product was poured into water and treated as described for the dibenzoyl compound. The oil produced in this way in one preparation had a rotation of + 2'30' in a 66 mm. tube a t 14'. For the purification, the same method (separation from alcoholic solution by means of water) has been adopted as for the dibenzoyl derivative. After three separations i t was found that the rotation was constant (aD = 2'58', 1=0*66, t = 20.5'). Another preparation had n rotation of 2'55' at 20' in t.he same tube. Ethyl octyl diacetyltartrate is a clear, viscous oil with a very slight rancid odour. It cannot be distilled, as on heating much above 100' it undergoes decomposition. 0.1772 gave 0-372s CO, and 0.1 148 H,O. The density and rotation have been determined a t various tempera- C = 57.38 ; H = 7.20.C,,H,,,O, requires C = 57-75 ; H = 8.02 per cent. tures. d 18*1'/4O = 1,0554. d 49.2'14' = 1.0271. d 31*5'/4O = 1.0429. d 70*5'/4" = 1*0071. + 2'56' 1.0553 + 4 '20" 3 14 1.0317 4 *63 3 36 1.0160 5 '37 4 14 0.9968 6'43 4 41 0.9800 7 -23 Rotation of ethJ octyl dictcetyltartrctte. (Length of polnrimeter tube = 66-04 mm.) Temperature. 1 Observed 1 Density at i to. rotation. [all). r 11 I D . ____- - + 15.71" 17 -32 20'08 24.05 27.04 Conclusions. From the results obtained with ethyl octyl tartrate, it is evident that the rotation increases with rise of temperature a t about the same rate as that of diethyl tartrate does : [al:Oo Diethyl tartrate (Pictet). ,. ... ... , . . Ethyl octyl tartrate ..................7-78 12.75 I€ we compare the rotations of ethyl octyl tartrate and its deriva- tives with those of diethpl tartrate, we notice a striking similarity, in agreement with the rule suggested by Guye (Guye and Babel, Arch. 7.66" 1399O1110 McCRAE : ETHYL SEC.OCTY L TARTRATE, Xci. phys. nat. Geneva, 1899, iii, 7, 114 ; and Guye, this vol., p. 476), namely, that substitution effected sufficiently far removed from the asymmetric carbon atom scarcely modiEes the rotatory power. Using the diethyl compounds as starting point, the following table shows that the replacement of a methylene hydrogen atom of one of the ethyl groups by n-hexyl gives rise to only a comparatively small change in the molecular rotation. [ M 1:o [MI? Diethyl tartrate" ........................+ 1 5 ~ 7 8 ~ + 27.38O Ethyl octyl tartrate .................... +22-55 +37*17 Ethyl octyl diacetyltartrate.. .......... + 15-80 + 27-04 Diethyl diacetyltartrate? ............... + 9.9 + 18-26 Diethyl dibenzoyltartratet ............ - 247.1 - 251.6 Ethyl octyl dibenzoyltartrate ......... - 245.8 - 222-8 The influence of temperature on the rotatory power of all these compounds is the same, namely, with rise of temperature the dextro- rotation increases (or the lavorotation diminishes). Frankland and Wharton (Zoc. c i t , ) have found that the laevorota- tion of diethyl dibenzoyltartrate increases with rise of temperature up to a maximum reached at about 60°, and thereafter it progressively decreases. Allowing, therefore, for this anomaly, the influence of temperature on diethyl dibenzoyltartrate is the same as on the other tartrates mentioned, although the two numbers given would appear to contradict this. No corresponding anomalous behaviour has been observed with ethyl octyl dibenzoyltartrate, but attention may be directed to the observation that the rotation of both this and the diacetyl derivative is considerably more affected by change of tempera- ture near looo than it is at low temperature. The expense incurred in the prosecution of t h i s work has been defrayed by a grant from the Research Fund of the Chemical Society, I desire here to acknowledge my indebtedness for this, and also to express my thanks to Dr. Patterson for so kindly placing his Laurent polarimeter at my disposal. THE YORKSHIRE COLLEGE, LXEDS. * Pictct, Jahresber., 1882, 856. t McCrae and Patterson (Zoe. cit.). $ Franklaud and Wharton (Zoc. cit.).

ISSN:0368-1645    

DOI:10.1039/CT9017901103

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

THE ALUMINIUM-MEltCURY COUPLE. PART 111. 11 11 CXX.-The Aluminium-Mercury Couple. P a ~ t III. Chloriiaatio f h o f Aqeornatic Hydrocarbons in pre- sence qf the Couple. The Constitution o f the Dic hloro t o luenes. By JULIUS 13. COHEN and HENRY D. DAKIN, the Yorkshire College. Introduction. THE readiness with which the aromatic hydrocarbons undergo bromi- nation in presence of the aluminium-mercury couple (Trans., 1899, 75, 893) suggested a series of experiments on the chlorination of these hydrocarbons under similar conditions. By passing dry chlorine into benzene in presence of a fragment of the couple, chlorination proceeds actively, the liquid becoming darker in colour whilst torrents of hydrochloric acid are evolved. The couple is only slightly attacked. By interrupting the process when a certain increase in weight had been obtained, the different chlorination products from the monochloro- benzene to the hexachlorobenzene were, in turn, isolated.Where the products were solid, it was necessary to add carbon tetrachloride to keep the substance in solution during chlorination. Similar experi- ments were carried out with toluene. The systematic study of the action of chlorine on toluene dates from the year 1866, when Beilstein and Geitner (Arznalen, 1866, 139, 331) discovered the action of chlorine on hot and cold toluene in pro- ducing substitution in the side-chain or nucleus, and showed a t the same time that by the use of iodine-a halogen carrier first employed by Hugo Muller-substitution may be confined to the nucleus.Since then, the action of chlorine on toluene in presence of different ‘‘ halogen- carriers ” has been repeatedly investigated with the object of orienting the products formed. The data which have thus been accumulated by different observers are very voluminous, but are so conflicting, that at the present time our knowledge of the products of this simple reaction is very indefinite. It was in attempting to collect evidenae of the constitution of the chlorine derivatives of toluene by reference t o the work of previous observers that we first realised its unsatisfactory character and deter- mined to make a complete study of the whole subject. The conflicting nature of the evidence will be readily understood from the following brief summary. Beilstein and Geitner (Zoc.cit.) and Beilstein and Kuhlberg (AiznccZen,1112 COHEN AND DAKIN: 1869, 150, 313 ; 152, 224) in their first papers describe only one monochlorotoluene, whilst Hiibner and Majert (Ber., 1 S73, 6, 790) announced the discovery of two, since identified as the ortho- and para- compounds, Beilstein and Kuhlberg (Annalen, 1869, 152, 224) found one dichlorotoluene, which on oxidation gave a dichlorobenzoic acid, m. p. 201-202°. Curiously enough they appear to have overlooked the existence of a second isomer, although they obtained from the mixture a dichlorobenzylidene dichloride, C,H,C)I,* CHCI,, which gave an aldehyde, and, on oxidation, a n acid, m. p. 12So. Aronheim and Dietrich (Be?*., 1875, 8, 1401), however, using molybdenum pentachloride as carrier, gave proofs of the existence of two dichlorotoluenes by separating the two dichlorobenzoic acids, m. p.201' and 1224 by fractional crystallisation of the barium salts. This agrees substantially with the results of Beilstein and Kuhlberg. R. Schultz (Annalen, 1877, 187, 260) repeated the work of the pre- vious investigators, and by fractional crystallisation of the barium salts of the benzoic acids obtained compounds of the m. p. 201°, 126O, and 156", and thus brought evidence of the existence of a third dichlorotoluene. The orientation of these compounds could only be determined with certainty after the pure dichlorobenzoic acids had been prepared. This work was carried out by Lellmann and Klotz (Annalen, 1885, 231, 308), who prepared four of the six isomers, the whole number being subsequently completed by Wynne and Greeves (Proc., 1895, 11, 151).As certain discrepancies appear in the results of various observers, we have also prepared the same series of acids and the combined results are tabulated below. Melting points of dichlorobenzoic acids. CH,=l. 2.3 2'4 2.5 2.6 3'4 3 -5 Lellmann and Klotz. Wynne. I--__ - 164" 158" - 153-5 152 - 139 j 202 C. and D. I - ___~--- 163" 153 159-160 139-140 200-201 182.5-103 Other observers. l- 156" (Claus) * 166" (Seelig) 128" (Rcilstein) 126.5" (Schultz) 132" (Claus) 182" (Claus) -* Clsus and-Bucher (Ber., 1887, 20, 1621) obtained this acid by the action of bleaching powder or potassium chlorate and hydrochloric acid upon benzoic acid. It was then converted into a dichlorobenzene which was identified as the ortho- compound. The melting points of Schulta'a three acids are in fair agreement with those of the 3 : 4-, 2 : 4-, and 2 : 6-compounds, the only doubt existingTHE ALUMINIUM-MERCURY COUPLE.PART 111. 11 I3 between the 2 : 3- and 2 : 4-compounds. But a later investigation of Seelig (Aiznnlen, 1887, 237, 139) on the action of chlorine on toluene in presence of ferric chloride or molybdenum chloride has introduced new features into the problem. H e gives evidence only of a 2 : 4- and a 2 : 3-compound, no mention being made either of a 3 : 4- or a 2 : 6- compound. As this is much the most elaborate investigation on the subject, the evidence which he adduces may now be briefly reviewed. According to Seelig, the 2 : 3- and 2 : 4-dichlorotoluenes which are formed map be separated by fractional crgstsllisation of their calcium sulphonates.Each dichlorotoluene forms a crystalline dinitro-derivative, the 2 : 3-compound melting at 121" and the 2 : 4-compound melting at 1 0 1 - 1 0 2 O . Evidence of their constitution is derived by Seelig from the follow- ing facts : (1.) The first products of chlorination consist of a mixture of ortho- and para-monochlorotoluenes. If either of these componnds is chlorin- ated, a mixture of the same two trichlorotoluenes results. Two of the chlorine atoms in these compounds will therefore be in positions 2 : 4. '\/ C1 The position of the third chlorine atom is determined as follows. Each of the trichlorotoluenes mas converted into a dinitro-derivative, which was reduced t o a diamino-compound.One of the diamino- compounds when heated with acetic anhydride forms an anhydro-base, and therefore contains the two amino-groups in the ortho-position. The second diamino-compound, on oxidation, yields a quinone and consequently has the two amino-groups in the para-position. The two diaminotrichlorotoIuenes will be represented thus : CH, CH, C1 c'1 that is to say, the trichlorotoluenes have the chlorine atoms in the 2 : 3 : 4- and 2 : 4 : 5-positions. This leaves a choice between the 2 : 3- ; 2 : 4- ; 2 : 5-, and 3 : 4-formulzle for the dicblorotoluenes. Now if ortho- and para-monochlorotoluene are chlorinated so as to form dichlorotoluenes, Seelig found that the orthu-compound yields1114 COHEN AND DAKIN: two, an a- and /3-dichlorotoluene, whereas the para-compound yields only one, namely, the j3-compound.The P-compound, since it is derived from both ortho- and para-monochlorotoluene, must have the 2 : 4-formula, which Seelig confirmed by converting it into the 2 : 4- dichlorobenzoic acid, m. p. 158', obtained by Lellmann and Klotz (loc. cit.). The constitution of the a-compound must lie between the 2 : 3- and 2 : 5-formula, since it is obtained from the o-monochloro- toluene. The a-compound yields on oxidation a dichlorobenzoic acid, m. p. 166'. This does not agree with the melting point of the 2 : 5- compound which Lellmann and Elotz had previously ascertained to be 153'. Seelig therefore concludes that the second or a-dichloro- toluene has the 2 : 3-formula. Wynne (Trans., 1892, 61, 1051) regards the evidence in favour of the 2 : 3-formula as inconclusive, and from a comparison of the sodium and barium sulphonates considers the 2 : 5-formula as more probable.Armstrong (Trans., 3892, 61, 1035) bases his objection on the analogy offered by the bromination products of toluene studied by Miller, and he also points t o the 2 : 5-formula as the more probable. Miller (Trans., 1892, 61, 1023) states, but on no visible grounds, that by brominating ortho-bromotoluene, 2 : 5-dibromotoluene appeared as the chief and 2 : 4- as a subsidiary product, whilst from para-bromo- toluene he obtained 3 : 4 - as the chief and 2:4- as the subsidiary product. On the other hand, contrary evidence is afforded by the work of Willgerodt and Salzmann (J. pr. Chm., 1889, [ii], 39, 465), who showed that by brominating o-chlorotoluene the bromine forms the 2 : 4- and 2 : 6-compounds, whilst by chlorinating p-bromotoluene, chlorine forms the 2 : 4- and 3 : 4-compounds, no 2 : 6-compound being observed.Since then Claus and Stavenhagen (Annalen, 1892, 269, 224) have found that by chlorinating o-chlorotoluene-one of the pro- ducts of the chlorination of toluene-two dichlorotoluenes are formed, which on oxidation give the 2 : 4- and 2 : 6-dichlorobenzoic acids, from which it appears almost certain that 2 : 6-dichlorotoluene is one of the direct products of chlorination, a fact which is in agreement with the previous observation of Schultz and confirms that of Willgerodt and Salzmann. I f we take the combined results of all these observers, we have more or less clear evidence of the existence of four dichlorotoluenes produced by chlorinating toluene in presence of molybdenum or ferric chloride : 2 : 3-, 2 : 4-, 3 : 4-, 2 : 6-, and a suggestion unsupported by any evidence of a fifth, 2 : 5-dichlorotoluene.No single observer has, however, succeeded in identifying more than three out of the five isomers referred to. Both Wyune and Armstrong throw doubt on this result.THE ATJJMIKIUM-MERCURY COUPLE. PART 111. 1115 The reason far these conflicting views is readiIy explained. In chlorinating toluene, a liquid mixture of dichlorotoluenes is formed, from which it is impossible to isolate the different constituents by any process of fractional distillation, seeing that their boiling points lie within a few degrees of each other.The only method which is avail- able is to convert the liquid into a solid derivative, of which the fol- lowing are most readily prepared: nitro- or dinitro-compound, sulphonic acid, its salts, chloride, amide, or anilide, or the corresponding benzoic acid, and t o separate the products by fractional crystallisation. The melting point may then be determined, and the identity of the substance established by comparison with that of a pure product of known con- stitution. This method may lead to a form of error into mhich earlier investigators fell. Unless the whole material is investigated from start to finish, some of the products may escape observation. Thus, Beilstein and Kuhlberg carefully fractionated their crude dichloro- toluene until a constant boiling fraction mas obtained.No doubt a portion of the products was thus eliminated a t the outset. This frac- tion mas oxidised, and the acid which first separated was recrystallised until it had a constant melting point, no other product being sought for in the mother liquor. Thus the'acids which were discovered later by Schultz escaped observation. Seelig has committed errors of a much more serious kind, for he has, apparently, not only omitted to look for compounds obtained by previous observers, but has failed to compare some of his products with the pure substances of known constitution. To quote instances, no attempt was made to isolate the acid (m. p. 125') obtained by Aronheim, and also by Schultz, and again, the dinitro-compound of m.p. 121' is assumed to be a derivative of the 2 : 3-dichlorotoluene, whereas if he had taken so elementary n precaution as to nitrate pure 2 : 3-dichIorotoluene, he would at once have convinced himself of his error, as this compound melts a t 71-72". The process of fractional crystallisation is also attended with diffi- culties, which are emphasised in the case of compounds possessing, like the derivatives of the dichlorotoluenes, not only similar chemical pro- perties, but often nearly identical solubilities in various media, Thus we obtained a nearly constant melting fraction on repeatedly recrys- tallising some of the dinitro-derivatives, which subsequently proved to be a mixture. It is only by preparing a variety of derivatives from the liquid mixture that this difficulty may be overcome.A number of oppor- tunities is thereby offered to each isomer of establishing its identity by a distinctive property of one at least of its derivatives. I n pursuing this idea, our research has necessitated the fractional crystallisation of certain of the nitro- and dinitro-derivatives, sulphonic1116 COHEN AND DAKIN: Snlphonic chlorides. acids, chlorides, arnides, and benzoic acids of the mixed dichlor otolu- enes, as well as the preparation of the pure substances for comparison. The latter are tabulated below, the table also including the results obtained by Wynne (Trans., 1892, 61, 1045). Sulphonamides. Melting points of the dekmtives of the dichlorotohenes. Nitro. ~ ~~ 2 : 3 2 : 4 2 3 6 2 : 6 3 : 4 3 : 5 Diiiitro. 54-55 50-51 53 63-64 61-62 I .104 100-101 121-122 91.5-92'5 99-100 505-51'5"l 71-72' I C:. and D. Wyiiiie. 71" 177 45-46 191 - 204 81 189 44-45 168 ___._ C. niid D. 222" 176 191 -192 204 190-191 168-169 We may sum up our results as follows : Using the aluminium-mercury couple as 'carrier,' we have established the presence of the 2 : 3-, 2 : 4-, 2 : 6-, and 3 : $-compounds, and the probable existence of small quantities of the 2 : 5-compound. This is in substantial agreement with the products formed with molybdenum or ferric chloride as ' carrier.' In other words, four, and probably five, out of the possible six isomers are produced, the only cornpound of which me could find no trace being the 3: 5-isomer. Their presence has been determined from the following evidence.We have taken as the starting point pure ortho- and para-mono- chlorotoluene, which were known to form the first products of the chlorination of toluene, which we have contirmed by oxidising the mixture to the benzoic acids and separating the ortho and para- compounds. Chlorination OJ Parcc-cl~lorotoluene. 2 : 4-Bicl~lomtoZuene.-Evidence of the presence of this compound was obtained by converting the mixture into the dinitro-derivative and fractional crystallisation. The dinitro-compound melting at 103" was isolated, which is identical with that obtained from the pure 2 : 4- dichlorotoluene. On oxidation of the mixed dichlorotoluenes t o the corresponding benzoic acids, and by fractional crystallisation of t h e barium salts, the benzoic acid, m. p. 159q was obtained, corresponding to the 2 : 4-benzoic acid. Also the sulphonic chloride, m.p. 70°, and the sulphonamide, m. p. 176", were prepared by sulphonation of the mixed dichlorotoluenes and fractional crystallisation,THE ALUMINIUM-MERCURY COUPLE. PART 111. 1117 3 : 4-DichZorotoZztene.-The dinitro-derivative, m. p. 90-92’, was separated from the mother liquors in the fractionation of the above 2 : 4-dinitro-derivative. The corresponding benzoic acid was obtained from the crystallisation of the barium salts described above. I t melted a t 200--201° in agreement with that of the pure 3 : 4-compound. Chlorination of O~.tho-c~Zorotolzcens. 2 : 3-DichZos*otoZuene.-The product of chlorination was sulphonated, the barium salt fractionated, and the sulphonamide which was obtained melted a t 221”, in agreement with the pure compound.The mixed barium salts were then desulphonated, and the dichlorotoluenes con- verted into their dinitro-derivatives. By fractional crystallisation, a portion was separated having the m . p. 72’. 2 : 6-DichZorotoZuene.-Fi*om another fraction of the same mixture of dinitro-compounds, the compound melting a t 121-122” was isolated, corresponding to the pure 2 : 6-compound. The crude dichlorotoluene was also oxidised to the corresponding benzoic acid. On treating the mixed acids with methyl alcohol and hydrochloric acid in the cold, sonie free acid mas isolated. According t o Victor Aleyer’s ‘( esterifica- tion law,” this should be a diortho-substituted acid, and the melting point, 137-139’, corresponds to that of the 2 : 6-dichlorobenzoic acid.2 : 4-Dici~ZorotoZuene.--The portion unsulphonated with concentrated sulphuric acid was treated with fuming sulphuric acid, and the barium salts thus obtained were fractionated. One fraction was converted into the sulphonamide, m. p. 176”, which agrees with that of the pure compound. From the dinitro-derivatives, obtained by nitrating the mixture of chlorinated products, a compound melting at 1 0 3 O mas isolated. 2 : 5-BichZorotoZzcene.-The only evidence obtained of the presence OF this compound was from the crude dichlorotoluene sulphonated with fuming sulphuric acid, from which the previous (2 : 4-) derivative mas prepared. This was converted into the sulphonamide and fractionated. The first crop of crystals melted at lS9-191’, which corresponds to the 2 : 5-compound.The evidence is admittedly incomplete, and is due t o the fact that none of the simple derivatives of the 2 : 5-com- pound show sufficiently marked characteristics to render them easy t o identif J . Chlorination of Meta-chlorotoluene. To make the series complete, we have included the chlorination of m-chlorotoluene within the scope of this research, a subject which has hitherto not been investigated. 2 : 5-0ichZorotoZuene.-It waa identified by the melting point, VOL. LXXIX. 4 u1118 COHEN AND DAKIN: 100-lO1°, of the dinitro-compound, which was obtained by fractional crystallisation of the mixture of which it formed a large proportion. 3 : 4-DichEorotoZuene.-This formed the only other constituent, and was identified by oxidising it to the benzoic acid, m.p. 200-201°, and by isolating from the mixed dinitro-compounds a portion melting at 92'. No trace of either the 2 : 3- or the 3 : 5-compounds could be detected. The absence of the 3 : 5-compound would be anticipated from the well- known property of the chlorine atom to enter the ortho- or para- and not the meta-position to the methyl or halogen groups. But the reason for the absence of the 2 : 3-compound is not so apparent, and may be referred t o space interference of the meta-groups, which might prevent the introduction of the halogen between them. The unsatisfactory nature of the research on the bromination of toluene, to which reference has been made (p. 1114), has decided us to repeat this investigation on similar lines to the present one, and we have already made some progress in this direction.We are also completing the investigation of the trichlorotoluenes obtained by the chlorination of the dichlorotoluenes. EX P E RIME NT AL. For purposes of reference, the experimental part has been divided Page I. Chlorination of benzene .......................................... 1118 toluene .......................................... 11 19 111. Preparation of the dichlorotoluenes and their derivatives from ortho-, para-, and meta-chlorotoluene .................. 1121 IV. Preparation of the six pure dichlorotoluenes an'd tbeir derivatives ........................................................ 1127 into the following sections : 11. 9 ) I. Chlorination, of Benzene. iMonochZoro6enzene.-Chlorine washed and dried by concentrated sulphuric acid was passed into benzene contained in a wash-bottle c6oled in ice.Fifty grams of benzene, previously distilled over sodium, were introduced into the wash-bottle, together with about 0.5 gramof the aluminium-mercury couple. On passing in the chlorine, the benzene becomes first yellow, then rapidly turns dark violet, and torrents of hydrochloric acid gas are evolved, the couple remaining practically unattacked. When the benzene had increased 13 grams in weight, the process was stopped. The liquid was then washed with caustic soda solution, dehydrated over calcium chloride, and fractionated, with the following result :THE ALUMINIUM-MERCURY COUPLE. PART 111. 1 I1 9 Below 127" ............ 4 grams.127-137 ............ 50 ,, 137-1 60 5 9 , Above 160 ............ 4 ,, ............ The amount of crude monochlorobenzene corresponds to about 70 per cent. of the theoretical yield, Para-diciLZorobenxene.-From the residue boiling above 160' a solid separated on cooling in ice and salt, which was drained and dried. It was recrystallised from dilute alcohol and melted at 54-56', which is the melting point of p-dichlorobenzene. 5%- and ~etrac~Zorobenxene.-Ten grams of crude chlorobenzene and 10 grams of carbon tetrachloride were introduced into a U-tube with a small piece of the couple and chlorine passed in. The liquid first became yellow, and then a more vigorous action occurred, which was indicated by a rise of temperature and a rapid change of colour to dark brown, This sudden change may possibly correspond to the passage from the additive to the substitution compound, referred to by Seelig in the case of toluene (Anncden, 1887, 237, 170).When the requisiteamount of chlorine had been absorbed, the current of gas was stopped, and the mixture, to which a little more solvent was added t o bring the solid into solution, was shaken with caustic soda, dehydrated, and distilled. The portion boiling a t 130-230*, and amounting to 14 grams, solidified on cooling. It was drained and recrystallised. The greater portion (7 grams) melted at 138', which corresponds with the 1 : 2 : 4 : 5-compound, The oil which was drained off solidified in a freezing mixture, and is probably the 1 : 2 : 4-trichlorobenzene, which melts at 16'. HexachZorobenneene.-One gram of the pure tetrachlorobenzene was dissolved in 15 parts of carbon tetrachloride and introduced into a U-tube, with a fragment of the couple and chlorine passed in for some time.A vigorous reaction occurred, heat was evolved, and the liquid became dark violet. The product was washed, and the carbon tetra- chloride removed by distillation. The solid residue was washed with ether to remove yellow colouring matter. A theoretical yield (1.4 grams) of hexachlorobenzene was obtained melting a t 228-229O. About half a gram melted at 127-130". II. Chlorination of Toluene. Monochloroto1uene.-Chlorine mas passed into 62 grams of dry toluene in presence of the couple until an increase of 19.5 grams was obtained. The product mas then washed, dried, and fractionated, as follo\.vs : 4 a 21120 COHEN ANI) DAKIN: Below 140° ............1.5 grams. 140- 163 ............ 68.7 ,, Above 163 ............ 2 ,, The yield of crude chlorotoluene is about 80 per cent. of the The larger portion was distilled with a Hempel column, theoretical. and the following fractions were obtained : Below 130' ............ 3-2 grams. 130-150 ............ '7 ,, 150-155 ............ 41 ,, 155-163 ............ 17.5 ,, With the exception of about a gram, the large fraction boiled con- stantly at 154-155', and is therefore mainly o-chlorotoluene, b. p. 154'. The para-compound, according to different observers, boils at 160' nnd 163'. I n order to identify the ortho-compound, it was oxidised to chlorobenzoic acid. Five grams of the chlorotoluene, 16 grams of potassium permanganate, and 210 C.C.of water were boiled together for 7 hours with a reflux condense?. Sulphur dioxide was then passed into the liquid to dissolve the manganese dioxide and precipitate the acid. The chlorobenzoic acid was then boiled with water, which left' 0-7 gram undissolved. This residue melted at 235', and was therefore p-chlorobenzoic acid (m. p. 236'). The solution deposited 2.8 grams of crystals which, after recrystallisation, meltedat 134--135O, corresponding to the melting point of the o-chlorobenzoic acid. The same process was repeated with a fraction boiling a t 157-1639 This was much less readily oxidised, but eventually from 5 grams 2.65 grams of mixed acids were obtained, which were separated by hot water, and gave 0.9 gram of the ortho-compound melting a t 132--134', the remainder being the para-compound melting at 233-234'.The mixture of crude monochlorotoluenes consists therefore of, approxi- mately, 65 per cent. of ortho- and 35 per cent. of para-compound. This agrees with Seelig's results (Zoc. cit.). DichZoTotoZzcene.-Sixty grams of toluene were chlorinated as before until the increase in weight amounted to 36 grams. The liquid was purified and fractionated, as follows : 110-145O ............ 18.5 grams. 180-210 ............ 65 ,, Above 210 ............ 2 ,, 145-180 ............ 7.5 ,, The portion boiling below 180' mas again chlorinated and distilled. It gave : Below 180' ............ 12 grams. 180-210 ............ 12 ,,THE ALUMINIUM-MERCURY COUPLE. PART 111.11 21 Thus 77 grams of crude dichlorotoluene were obtained from 60 grams of toluene, corresponding to 74 per cent. of the theoretical yield. The 77 grams were refractionated. 160-194O ............ 28 grams. 194-200 ............ 50 ,, Above 200 ............ 5 ,, The 22 grams, b. p. 160-194O, were subsequently re-chlorinated for the preparation of trichlorotoluene. An attempt was made to identify the dichlorotoluenes by oxida- tion to the corresponding acids with potassium permanganate, but the process gave a very unsatisfactory result and was abandoned. From 30 grams of crude dichlorotoluene, after boiling with 80 grams of permanganate and 1200 C.C. of water for 7 days in a calcium chloride bath, only 3 grams of acid were obtained melting a t 157-164'. A slight modification of this method, which was re- commended by Claus and Stavenhagen (Annalen, 1892, 260, 224), has not in any way helped to convince us of i t s efficacy (see p.1132). Tricklorotoluene.-The 22 grams of liquid boiling at 160-1 94O, obtained as above described in the preparation of dichlorotoluene, were further chlorinated until there was an increase of 4.5 grams in weight. After the usual purification, the liquid was fractionated as follows : Below 220" ............ 4 grams. 220-240 ............ 17 ,, 240-263 ............ 13 ,, The last two fractions solidified on cooling. Both portions were separately recrystallised from alcohol, and the two principal frac- tions which were obtained melted a t 82' and 40-42'. This agrees exactly with Seelig's melting points of the two trichlorotoluenes which he isolated.A t least two trichlorotoluenes are therefore present . III. Sixty-one grams of p-chlorotoluene (b. p. 156-160°), prepared by Gattermann's method from p-toluidine, were treated with chlorine in presence of the couple, until an increase of 20 grams was obtained. The product was purified and distilled. Dichlorotoluene and its Derivutives from Pam-chlorotoluene. Below 190" ............ 1.5 grams, 190-210 ............ 59.5 ,, Above 230 ............ 2 ,? 210-230 ............ 13.5 ,,1122 COHEN AND DAKIN: The two intermediate fractions were redistilled. 190-197O ............ 22 grams. 197-205 ............ 30 ,, Nitq*atim of the Mixed Bichloi*otoluenes. Each of the above two fractions was nitrated as follows. Five grams of the dichlorotoluene were added in small quantities to a cooled mixture of 17 grams of concentrated sulphuric acid and 34 grams of fuming nitric acid (sp.gr. 1.5). The mixture was kept cool until all the dichlorotoluene had been added. It was then warmed on the water-bath for about 15 minutes and poured on to crushed ice. The solid was filtered, washed with water, and dried on a porous plate. The substance was fractionally crystallised from alcohol and from glacial acetic acid. Five grams of dichlorotoluene, boiling at 190-197°, gave 5.4 grams of a dinitro-compound, of which 3.7 grams melted at 102-103°, corresponding to the 2 : 4-compound. The remainder melted indefinitely at about 80°, but by prolonged fractionation a small quantity of fine-needles was obtained melting at 90-92', which corresponds to the 3 : 4-derivative.Six grams of the fraction boiling at 197-205" gave 7.7 grams of dinitro-compound, of which 4.1 grams melted a t 101-103°. The remainder melted a t a lower temperature, and was probably a mixture of the 2 : 4- and 3 : 4-derivatives, as in the previous fraction. Oxidation of the Mixed Dichlorotoluenes, Five grams of the dichlorotoluene were heated for 6 hours at 140' in a sealed tube with a mixture of 13 C.C. of concentrated nitric acid (sp. gr. 1*4) and 16 c.c, of water. The product was made alkaline with caustic soda, and a trace of unoxidised substance removed by steam distillation. The mixed dichlorobenzoic acids were then pre- cipitated by the addition of hydrochloric acid. After filtration and washing, the benzoic acids were converted into their barium salts by boiling the aqueous solution with a slight excess of baryta.The salts were repeatedly crystallised from hot water. The most insoluble barium salt, after three crystallisations, yielded a dichlorobenzoic acid melting at about 1909 The acid was then recrystallised four times from dilute spirit, when it melted sharply a t ZOOo, corresponding to the 3 : 4-dichlorobenzoic acid. The more soluble barium salt yielded an acid melting at about 150'. On repeatedly crystallising, a pure product was isolated melting a t 169', corresponding t o the 2 : 4-dichlorobenzoic acid.THE ALUMINIUM-MERCURY COUPLE. PART 111. 1123 XuZphonution of the Jlixed Dichlorotoluenes. Five grams of the dichlorotoluene mixture were sulphonated with fuming sulphuric acid and the sodium salt separated by pouring into brine.This was converted into the sulphonic chloride with phos- phorus pentachloride. On fractional crystallisation of the sulphonic chloride from petroleum, a product melting a t 70° was obtained, corre- sponding to the 2 : 4-derivative. The sulphonamide was then prepared, which, on fractional crystallisation, indicated the presence of two corn- pounds, only one of which, the 2 : 4-sulphonamide melting att 176", could be prepared in the pure state, DichZomtoZuew,e cmd its Derivatives fropm, Ortho-chlorotoluene. o-Chlorotoluene was obtained from o-toluidine by Wynne's modifi- cation of Sandmeyer's method (Trans., 1892, 61, 1072). Fifty-four grams of the product boiling a t 154-158' were chlorinated as pre- viously described, and the following fractions obtained : Below 190" ............3.5 grams, 190-210 ............ 51 ,, 210-230 ............ 7 ,, Above 230 ............ 3 ,, The fraction boiling at 190-210' was then redistilled. 190-195" ............ 7 grams. 195-208 ............ 42 ,, Nitrution of the Mixed DicAZorotoluencs. Five grams of dichlorotoluene were nitrated as previously described and the product fractionated. 0.135 gram of a pure substance melting at 102" was isolated, which corresponds to the 2 : 4-derivative, and a large quantity of a mixture of the nitro-compounds, from which no pure product could be separated. This method of attacking the problem was therefore abandoned. XuZphortntion of the Mixed Dichlorotoluenes.I n order to obtain direct evidence of the existence of the different dichlorotoluenes in the mixture, the product was sulphonated, and the sulphonic acids separated and converted into the sulphon- amides. Eighty grams of dichlorotoluene, boiling a t 195--208O, were heated on the water-bath with four times the weight of concen- trated sulphuric acid, and stirred continuously with a mechanical1124 COHEN AND DAKIN: stirrer. The mixture was then diluted with water, and unchanged oil removed by distillation in steam. The sulphonic acid was con- verted into the soluble barium salt by the addition of barium car- bonate, and the liquid filtered. The residue was boiled up repeatedly with fresh quantities of water and the united filtrates evaporated.In this way, 36 grams (fraction 1) of the barium salt crystnllised out, and a further 7 grams (fraction 2) were obtained by evapora- tion of the mother liquor. The recovered portion, which had not been sulphonated, amounted to 58 grams, and was treated with 160 grams of 20 per cent. fuming sulphuric acid. The dichlorotoluene, on shaking, rapidly dissolved. It was diluted and distilled in steam, and 10.5 grams of unchanged dichlorotoluene were recovered. Fraction 1 gave a sulphonamide which softened at 204" and melted a t 210-212'. After five recrystallisations from alcohol, a pure product melting a t 221-221;' was obtained. The sulphonamide which was mixed with it was subsequently shown to be the 2 : 6-derivative melting a t 204'. The remainder of the barium salt from fraction 1 was then de- sulphonated by Armstrong and Miller's method (Trans,, 1884, 45, 148).Twenty-two grams of the barium salt, 8 C.C. of water, and 100 grams of concentrated sulphuric acid gave 8 grams of dichloro- toluene boiling a t 195-1 96'. This dichlorotoluene was converted into the dinitro-compound in the ordinary way, and by careful frac- tional crystallisation from glacial acetic acid the following pure com- pounds were obtained. (i) A dinitro-compound melting at 130-121° corresponding to the 2 : 6-derivative; (ii) a compound melting a t 71-72', corresponding to the 2 : 3-derivative ; (iii) a very small quantity of prisms melting at 103', identified as the 2 : 4-compound. The second small fraction of the barium salt gave a sulphonamide which melted indefinitely a t about 180".No pure product was separated from it, It was probably mainly the 2 : 4-derivative. The third crop of barium salt was converted into the sulphon- amide, which was then fractionally crystallised from alcohol. Two compounds were isolated, one melting at 176O, which was identified as the 2 : 4-derivative, the other melting at 189-19lo, which mas possibly the 2 : 5-derivative. The melting point was unchanged by recry stallisat ion. Oxidation of the Nixed Dichlorotoluenes. Five grams of the dichlorotoluene mixture were oxidised by heating for 6 hours t o 130" in a sealed tube with 10 C.C. of nitric acid (sp. gr. 1.4) and 20 C.C. of water. The dichlorobenzoic acids were separated and purified as previously described, (p. 1122). Five grams of the acids were dissolved in 60 C.C.of methyl alcohol, andTHE ALUMINIUM-MERCURY COUPLE. PART IIr. 1125 dry hydrochloric acid passed into the cold liquid to saturation. The liquid, after standing several hours, was poured into water, and the unchanged dichlorobenzoic acid and esters extracted with ether. The ethereal solution was then repeatedly extracted with small quantities of caustic soda solution, and the alkaline liquid, after boiling off any residual ether, was acidified with hydrochloric acid. The precipitated dichlorobenzoic acid contained some oily impurity, possibly nitro-compounds, which mere removed as far as possible by careful draining and pressing on a porous plate. The residual acid was then crystallised from water, 0.65 gram of acid being obtained, which melted indefinitely a t 120-1 34".The acid was then treated with methyl alcohol -and hydrochloric acid as be- fore, and after recrystallisation from dilute spirit, melted a t 137-139". This corresponds to the melting point of the 2 : 6-di- chlorobenzoic acid given by Wynne and Greeves (Proc., lS95, 11, 151. See also p. 1131) and obtained by ourselves. Dicldorotoluene and its Derivatives from Neta-chlorotoluene. m-Chlorotoluene mas prepared f r o a m-toluidine by Sandmeyer's reaction, using cold cuprous chloride solution. The yield from 75 grams of the base amounted to 62 grams of the pure compound boiling at 158-161". The chlorination mas carried out in exactly the same may as previously described, the yield of the mixed di- chlorotoluenes amounting to about 85 per cent.of the theoretical amount. Thirty grams of m-chlorotoluene mere chlorinated in presence of the couple until the theoretical amount of chlorine had been absorbed. Caustic soda was then added and the product distilled in steam. The distillate mas then separated, dried, and fractionated. The details of one experiment are as follows. Below 195O ............ 1 gram. Above 201 ............ 1.5 ,, 195-201 ........... 33 7, The constituents of the dichlorotoluene thus obtained were identified by means of their dinitro-derivatives and sulphonamides, and also by oxidation to the corresponding bsnzoic acids. Nitration of the Bixed Dichlorotoluenes. The dichlorotoluene mixture was nitrated in the ordinary way, and the dinitro-derivative separated and crystallised from acetic acid.The product melted indefinitely at 86-93O, indicating the presence of a mixture. It was then submitted to systematic fractional crystallisa-1126 COHEN AND DAKIN: tion, using acetic acid as solvent, The main product was found to consist of a dinitro-compound melting at 99-100°, identical with that obtained from 2 : 5-dichlorotoluene (m. p. 1OO-l0lo). From the mother liquors, a product was obtained melting indefinitely at 70-85'. On fractionating this further, a pure substance was separated melting at 92-93O, which is the same as that obtained from 3 :4-dichloro- toluene melting a t 91.5--92.5O. No other compoiinds having definite melting points were isolated. Oxidation of the Mixed DichlorotoZuerzes. The oxidation mas effected by heating the dichlorotoluene mixture with 7 parts by weight of dilute nitric acid in a sealed tube to 140' for 5 hours.The contents of the tube were dissolved in caustic soda, and the solution distilled in steam to remove a trace of unoxidised substance. The benzoic acids were then precipitated with hydro- chloric acid. An unsuccessful attempt was made to separate the con- stituents of the mixture by fractional distillation in steam. The acids were therefore converted into the barium salts, which were fractionally crystallised. The most insoluble fraction yielded an acid melting at 180-1 95', which, on recrystallisation from spirit, melted at 199-200', and therefore corresponds to the 3 : 4-compound. The more soluble barium salt yielded a large quantity of an acid which, after repeated crystallisation, melted at 146-1 48O.This acid probably consif mainly of the 2:5-compound (m. p. 153'), but the pure acid could not be obtained. Xu&honation of the Mixed Dicldorotoluenes, The sulphonation was undertaken with the special object of detect- ing the presence of any of the 2 : 3-derivative, as it yields a character- istic sulphonamide. An unsuccessful attempt was made to effect a partial separation of the mixture by using different strengths of sul- phuric acid for the sulphonation. As ordinary sulphuric acid had little action, the sulphonation was effected by means of slightly fuming acid, and the product converted into the barium salt. The salt was fractionally crystallised from water, and then the fractions converted into the sulphonamides. No indication was obtained of the 2 : 3-sulphonamide.The sulphon- amides of the 3 : 4- and 2 : 5-compounds previously shown to be present melt too closely together t o admit of separation, namely, 3 : 4- at 190-191' and 2 : 5- a t 191-192". No 3 : 5-dichlorotoluene could be detected in any of the reactions. The conclusion is therefore drawn that of the four possible dichloro-THE ALUMINIUM-MERCURY COUPLE. PART 111. 1127 toluenes theoretically obtainable from m-chlorotoluene, only the 2 : 5. and 3 :4-compounds are formed, the former being present in the larger quantity, IV. Preparation of the Six Dichlorotoluenes and their Derivatives. Preparation of 2 : 3-DichZorotoZuene. 3-Nitro-2-toluicZine.-2 : 3-Dichlorotoluene was prepared from the corresponding nitrotoluidine.Lellmann and Wurthner (Annalen, 1885, 228, 239) found that o-acetotoluidide gave on nitration two nitro- acetotoluidides, which were separated by means of fractional hydrolysis, followed by mechanical sieving of the mixed crystalline product. The two compounds were identified as the 2 : 3- and 2 : 5-nitro-derivatives. Reverdin and Crbpieux (Ber., 1900, 33, 2498) have described a more convenient method of separating the two isomers. They find that if the mixed product of nitration be hydrolysed with concentrated hydro- chloric acid and the acid liquid distilled in steam, the 2 : 3-compound is volatilised, whilst the 2 : 5-compound remains behind. From the results of a number of experiments, we find that the best results are obtained as follows.Fifteen grams of powdered o-acetotoluidide are added in small por- tions t o a mixture of 50 grams of fuming nitric acid and 18 grams of glacial acetic acid, the temperature being maintained at about 15'. If the liquid is cooled below this temperature, the reaction is suspended for a time until all the acetotoluidide has been added, when it sets in vigorously with rapid rise of temperature and ultimate decomposition. After standing some hours a t the ordinary temperature, water is added to the solution, and the precipitated nitro-compounds filtered off and washed. The substance is then placed in a flask with the addition of 40 C.C. of concentrated hydrochloric acid and, without any preliminary heating, distilled in steam. After a short time, orange coloured crys- tals collect in the receiver, distillation being continued until no more solid matter is carried over, an operation which lasts about 6 hours.The yield amounts to 6-7 grams of 2 : 3-nitrotoluidine. The 2 : 5- compound may be separated from the acid liquid remaining in the distilling flask. 2-ChZol.o-3-mitrotoluene.-Three parts of finely powdered nitrotolu- idine were suspended in 5 parts of concentrated hydrochloric acid and 4 parts of water, and the cooled liquid diazotised by the addition of solid sodium nitrite. I n this and in subsequent preparations we found the solid nitrite in coarse pieces to act more slowly and effectively and with a much smaller rise of temperature than the nitrite solution. When the base had gone into solution, the liquid was added to an ice-cold solution of1128 COHEN AND DAKIN: 4 parts of cuprous chloride dissolved in concentrated hydrochloric acid as described by Wynne (Trans., 1892, 61, 1072).When the evolution of nitrogen had ceased, the liquid was distilled in steam. An almost theoretical yield of chloronitrotoluene was obtained. 2 - ChZoro- 3 - toZuidine.-The above nitro-compound was reduced by means of a slight excess of stannous chloride dissolved in an equal weight of concentrated hydrochloric acid. The reaction, which was at first very vigorous, was completed by heating for an hour on the water-bath. At tbe end of this time, a clear solution was ob- tained which was poured into a basin and left to crystallise. The crystalline mass was pressed on the filter, and washed with a little con- centrated hydrochloric acid.A small quantity of tin was removed from the crystals by dissolving them in hot water and passing in sul- phuretted hydrogen. The sulphide was removed by filtration, the filtrate concentrated, and the crystalline hydrochloride used in the subsequent process. 2 : 3-Dichlorotoluene.-The conversion of chlorotoluidine into di chlorotoluene is carried out in the Bame manner as in the preparation of chloronitrotoluene from nitrotoluidine. The yield was nearly theoretical. On fractional distillation, 90 per cent. boiled at 204-206' at 755 mm. pressure. 2 : 3-BichZorobsnxoic cccicl.-One part of dichlorotoluene was heated with 6 parts of dilute nitric acid (2.5 vols. of concentrated nitric acid sp. gr. 1.4, 3 vols.of water) for some hours in a sealed tube to 140O. The contents of the tube were made alkaline with caustic soda and distilled in steam to remove unchanged dichlorotoluene. The chloro- benzoic acid was precipitated in the residue on the addition of acid and recrystallised from hot M bter. Nitro-2 : 3-dichZorotoZuene.-This compound was prepared by adding to 1 part of dichlorotoluene a cold mixture of 2 parts of nitric acid (sp. gr. 1.4) and 3 parts of concentrated sulphuric acid. The mixture was then heated for some time on the water-bath, and the nitro-com- pound precipitated by pouring on to crushed ice. It was recrystallised from a mixture of alcohol and acetic acid, and was obtained in the form of felted masses of fine needles melting sharply a t 50°5-51*50.C7H,CI;N0, requires C1= 34.41 per cent. Binitro-2 : 3-dich1orotoluene.- The dinitro-derivative was obtained by slowly adding to 1 part of dichlorotoluene 7 parts of fuming nitric acid (sp. gr. 1.5) and 38 parts of concentrated sulphuric acid. The reaction was completed by heating for some time on the water-bath, and the product then poured into water. The precipitated dinitro- It melted at 163'. 0.1640 gave 0.2292 AgC1. C1= 34.55.THE ALUMINIUM-MERCURY COUPLE. PART III. 11 29 compound was filtered, washed and dried, and recrystallised from glacial acetic acid or alcohol. The product was fractionally crystallised and proved to be uniform. It melted a t 71-72O. 0.1991 gave 0-2285 AgC1. C1= 28.32. C7H,Cl,(N0,), requires C1= 28.12 per cent. 2 : 3- DichZorotoZuenesu~phonamide. -The dich loro t oluene was sul- phonated by heating for a short time with three times the weight of fuming sulphuric acid, and the sulphonic acid converted into the barium salt in the usual way.The barium salt was then heated with an equal weight of phosphorus pentachloride, which yielded the sul- phonic chloride, and this was converted into the amide in the usual way. The sulphonamide, after recrystallisation from alcohol, melted at 222'. 2 : 3-Dichlorotoluene has been stated by Wynne (Proc., 1895, 11, 151) to yield two sulphonic acids on sulphonation, which may be separated by fractional crystallisation of their barium salts. Experi- ments made with the object of separating the two acids failed t o indi- cate the presence of a second acid.Preparation of 2 : 4-Dichlorotoluene. Ordinary dinitrotoluene was used for the preparation according to the method of Lellmann and Klotz (Annden, 1885, 231, 308). The di- nitrotoluene was first reduced t o nitrotoluidine with ammonium sul- phide. The product (m. p. 76') was then submitted to the same series of reactions as previously described under 2 : 3-dichlorotoluene. The yields throughout were satisfactory. Fifty grams of dinitrotoluene yielded 18 grams of 2 : 4-dichlorotoluene boiling at 198-200°. 2 : 4-DichZorobenxoic Acid.-This acid was obtained by oxidising the dichlorotoluene with dilute nitric acid in a sealed tube at 130-140°. The product was purified in the usual way, and crystallised from hot water in fine needles meiting at 159-160'. Nitro-2 : 4-dichlorotoZuene.-This compound was prepared in the same way as the 2 : 3-compound, and crystallised from spirit in long, hard needles melting at 54-55O.Seelig gives 5 3 O as the melting point of this substance. Dinitro-2 : 4-dichlo~otoluene was prepared in the manner described under the 2 : 3-compound. It crystallised from a mixture of glacial acetic acid and alcohol in 6ne prisms melting a t 104' (Seelig gives 2 : 4-0ichlorotoluenesuZphonamide.-2 : 4- Dichlorotoluene is readily sulphonated with fuming sulphuric acid. The sodium salt was separ- ated by pouring the product into brine, which was then converted 102O).1130 COHEN AND DAKIN: into the sulphonic chloride. The latter crystallised from petroleum ether in hard prisms melting at 71'. The sulphonamide was repeatedly crystallised from spirit and melted sharply at 176'.Preparation of 2 ; 5-Dichlorotoluene. Tho 2 : 5-dichlorotoluene was obtained in two ways, (i) by direct chlorination of o-acetotoluidide (Lellmann and Klotz, Annalen, 1885, 231, 319), and (ii) by the action of sodium hypochlorite on o-aceto- toluidide (Chattaway and Orton, Trans,, 1900, 77, 790). The two products were identical. (i) Following Lellmann and Elotz's directions, o-acetotoluidide was dissolved in sufficient glacial acetic acid to prevent crystallisation on cooling, and a current of dry chlorine passed into the cooled liquid. A vigorous reaction occurs with considerable rise in temperature. After a time, the solution suddenly becomes almost solid. Water was then added, and the crude chloroacetotoluidide filtered off and recrystallised from spirit.On hydrolysis with concentrated hydrochloric acid, the hydrochloride of chlorotoluidine separated in the form of crystals with a satin-like lustre. The amino-group was replaced. by chlorine by Wynne's modification of Sandmeyer's method already referred to. From 45 grams of o-acetotoluidide, 22 grams of crude dichlorotoluene were obtained, of which 19 grams boiled constantly at 198-199' under a pressure of 760 mm. The product solidified completely in a freezing mixture, and melted sharply at 5'. (ii) Twenty grams of o-acetotoluidide were shaken up with 400 C.C. N/2 sodium hypochlorite solution containing 20 grams of sodium bicarbonate and left to stand 24 hours. A little chloroform was added and the lower layer of liquid withdrawn. About an equal volume of glacial acetic acid and a drop of concentrated sulphuric acid were then added to the chloroform solution, which was warmed on the water- bath.The greater part of the chloroform evaporated, and the chloro- acetotoluidide was precipitated by pouring into water. The yield was nearly theoretical, The crude product mas recrystallised from dilute spirit and hydrolysed by boiling with excess of concentrated hydro- chloric acid. The subsequent operations were identical with those described under the first method. Twenty-four grams of the chloro- toluidine hydrochloride yielded 15 grams of pure dichlorotoluene boiling a t 198-200' a t 760 mm. and melting a t 5'. 2 : 5-BichZo~obenxoic acid was obtained by oxidation with dilute nitric acid a t 140'.The product was recrystallised three times from dilute spirit, and melted sharply at 153'. Nitro-2 : 5-dichZorototuene.-Great care was required in this prepara- tion to prevent the formation of the dinitro-derivative. The followingTHE ALUMINIUM-MERCURY COUPLE. PART III. 1131 proportions gave satisfactory results. A cold mixture of 1; parts of concentrated nitric acid (sp. gr. 1.4) and 3 parts of concentrated sul- phuric acid were slowly added to 1 part of the dichlorotoluene, any great rise of temperature being avoided, The mixture was subsequently warmed on the water-bath and the nitro-compound precipitated by water. On recrystallisation from a mixture of alcohol and ether, the nitro-compound was obtained in the form of fine needles melting at 50-51'.Ogll!12 gave 0.1655 AgCl. C1= 34.33. Dinitro-2 : 5-c2ichlorotoluene was prepared by the method already It was recrys- C,H,Cl,*NO, requires C1= 34-41 per cent. described in the case of the other dinitro-compounds. tallised from glacial acetic acid and melted a t 100-lO1°. 0.2630 gave 0*3015 AgCl. C7H,Cl,N,0, requires C1= 28.12 per cent. 2 : 5-Dichlorotolzceneszc~honccmide.-The dichlorotoluene was sul- phonated with fuming sulphuric acid, and the product separated as the sodium salt, The sulphonic chloride prepared by the action of phosphorus chloride on the sodium salt crystallised from ether in large, colourless plates melting a t 45-46O. The sulphonamide was obtained in the form of colourless needles melting a t 191-19Z3. C1= 38.33.Preparation of 2 ; 6-DichZorotoluene. The 2 : 6-nitrotoluidine, which served as the starting point for the preparation of the dichlorotoluene, we owe to the great kindness of Messrs. Green and Lawson, who obtained it in small quanties as a by-product by nitrating o-toluidine (Trans., 1891, 59, 1013). An almost theoretical yield of chloronitrotoluene mas obtained in the form of fine, yellow crystals by using Wynne's modification of Sandmeyer's reaction. The reduction of the nitro-compound was effected with stannous chloride, when the hydrochloride of chlorotoluidine was obtained in the form of white, glistening plates. From the latter, the 2 : 6-dichlorotoluene was finally prepared. Ten grams of the nitro- toluidine yielded 4.5 grams of pure dichlorotoluene, boiling constantly at 19So at a pressure of '760 mm.2 : 6-Dichlorobennxoic acid was obtained by oxidation in a sealed tube with nitric acid. After frequent recrystallisation, the product melted at 132-133', which agrees with the number given by Claus and Stavenhagen (Anncden, 1892, 269, 224), but is much lower than that given by Wynne and Greeves (139") or previously obtained by us from the mixture of dichlorotoluenes prepared by chlorinating o-chlorotoluene (see p. 1125). We concluded, therefore, that both Claus' and our pro-COHEN AND DAKIN: 1132 ducts were impure. I n our case, the fact was easily explained, for 2 : 6-dichlorotoluene is very difficult t o oxidise. Heated with very dilute nitric acid in a sealed tube, it is only slightly attacked, whereas with stronger acid nitro-compounds are formed which lower the melting point of the product.On the other hand, Claus and Stavenhagen's method (Zoc. cit.) of preparing 2 : 6-dichlorobenzoic acid from the crude chlorination product of o-chlorotoluene by oxidising with powdered potassium permanganate absolutely failed in our hands. Although we followed in detail the directions given, we found, after 2 days' boiling, that only a trace of dichlorotoluene had been attacked. We conclude that some important omission must have been made in the description of the method. We ultimately used the following method, which gave a sat'isfactory result. Five grams of the dichlorotoluene were oxidised with 10 C.C. of concentrated nitric acid (sp. gr. 1.4) and 20 C.C. of water for a day at 140' in a sealed tube.Caustic soda was added to the product, and the liquid distilled in steam. A small amount of solid distilled, which was identified as 2 : 6-dichlorobenzaldehyde. On acidifying the alkaline solution, an acid was obtained melting nt 128-132O. The impure acid was treated with a solution of 5 grams of stannous chloride in 10 C.C. of concentrated hydrochloric acid, and heated for an hour on the water- bath. The acid liquid was then extracted with ether, from which the dichlorobenzoic acid was obtained by washing with caustic soda solution. The acid was precipitated by the addition of hydrochloric acid. It was further purified by dissolving in methyl alcohol, saturating with dry hydrochloric acid, and allowing it t o stand for a time. On pouring into water and extracting with ether, the acid went into solution in the ether, from which it was extracted with caustic soda solution.On acidifying the alkaline solution, the acid was precipitated, and, after crystallisation from water, formed colourless needles melting at flitr0-2 : 6-dichlorotoluene was obtained in the usual way and crystal- lised from a mixture of alcohol and acetic acid in needles melting sharply at 53'. 139 -140O. 0.1222 gave 0*1720 AgC1. Dinitro-2 : 6-dichlorotoluene was prepared by the method previously It crystallised from alcohol in flattened needles melting C1= 34.79. C7H,Cl,*N02 requires C1= 34.41 per cent. described. at 121-122'. 0.0695 gave 0.0792 AgCl. 2 : 6-Dic~~lorotolzle~sulrphorcacmi~.-The dichlorotoluene waa readily C1= 28.17.C7H,Gl2(NO2), requires C1= 28.12 per cent.THE ALUMINIUM-MERCURY COUPLE. PART 111. 1133 sulphonated with fuming sulphuric acid, the product being separated as the sodium salt. The latter was converted into the sulphonic chloride and sulphonamide. The sulphonamide was crystallised from alcohol and melted a t 204'. Preparation of 3 : 4-Dichlorotoluene. The starting point for this preparation was the 3 : 4-nitrotoluidine supplied by Kahlbaum in beautiful, large, red crystals. The various steps in the process are the same as described in the case of the other nitrotoluidines and call for no special remark. Fifty grams of the nitrotoluidine yielded 17 grams of pure dichlorotoluene boiling a t 3 : 4-Dichlorobsnxoic acid was obtained by oxidising with dilute nitric acid a t 130-140'.The acid, which is slightly volatile in steam, melted at 200-2014 nitro-3 : 4-dichlorotoluene.-Care is required to prevent the formation of the dinitro-derivative. The best results were obtained by using 2 parts of concentrated nitric acid (sp. gr. 1.4) and 4 parts of concen- trated sulphuric acid to 1 part of dichlorotoluene. The product crys- tallises from alcohol and acetic acid in fine, long needles melting at 2 00-20 7 '. 63-64', 0.1000 gave 0.1395 AgCI. C1= 34.48. C7H5C12*N02 requires C1= 34.41 per cent. Dinitvo 3 : 4dichlorotoEuene was easily obtained, and crystallises from glacial acetic acid in long, nearly colourless needles melting a t 0,2557 gave 0,2920 AgCl. C1= 28.23. C7H4Cl,N,04 requires C1= 28.12 per cent. 3 : 4-Dicl~lorotolueitesulplzonarrLide -The dichlorotoluene was readily sulphonated and converted into the sodium salt. The sulphonic chloride solidifies readily and crystallises from ether in long needles melting a t €31'.91 *5-92*5'. The sulphonamide melts a t 190-191'. Prepariction of 3 : 5-Dichlorotoluene. The method employed for the preparation of the 3 : 5-dichlorotoluene is that described by Chattaway and Orton (Trans., 1900, 77, 791). Thirty grams of o-acetotoluidide were dissolved in 120 C.C. of glacial acetic acid, and a solution of 100 grams of bleaching powder in 2 litres of water were added. After standing 12 hours, the supernatant liquid wa8 decanted from the yellow oil. To the latter, about an equal volume of glacial acetic acid and a few drops of concentrated sulptiuric VOL. LXXIX. 4 HI134 THE ALUMINIUM-MERCURY COUPLE. PART 111. acid were added, and the solution was then warmed on the water-bath. After standing for a time, the solution was poured into water, when the dichloroacetotoluidide separated out. It was filtered, washed, and crystallised from spirit. The yield is nearly theoretical. The hydro- lysis was effected by heating 1 part of the dichloro-compound with 3 parts of concentrated hydrochloric acid to 150' in a sealed tube for 8 hours. I n this way, 21 grams of the dichlorotoluidine were obtained from 30 grams of the dichloroacetotoluidide. By using Claus' method, on the other hand, alcoholic potash only hydrolysed one-half of the compound after two days' boiling. This slow hydrolysing action of potash may be accounted for by space interference, as the amino- group is protected by two ortho-positions. The amino-group in dichlorotoluidine was eliminated by the method of Chattawag and Evans (Trans., 1896, 69, 850). Eleven grams of dichlorotoluene were obtained from 21 gramsof the base. It possessed the melting point 26' which is that given by Lellmann and Klotz (Annah, 1885, 231, 320). 3 : 6-Dichlorobenxoic acid was obtained by oxidation with dilute nitric acid at 150'. After repeated crystallisation, the compound was obtained in the form of fine, long needles melting at 182-183'. Nit~o-3 : 5-dichZorotoZzcene crystallises from a mixture of alcohol and acetic acid in needles melting at 61-62'. 0.1306 gave 0.1820 AgCl. C1= 34-45, C7H,C1,*N02 requires C1= 34.41 per cent. Dinitro-3 : 5=d~c~ZorotoZuene.-~he first preparations of this compound contained the trinitro-derivative, which is readily formed and crystal- lises in lustrous leaflets melting a t about 190'. The pure dinitro- compound was obtained by using the following quantities of materials. Pour parts of nitric acid (sp. gr. 105) and 4 parts of concentrated sulphuric acid were added to 1 part of the dichlorotoluene. The product crystallises from alcohol in long, white needles melting at 99-100'. 0.1212 gave 0.1390 AgCI. C1= 28.35. C7H,C1,N,0, requires C1= 28.1 2 per cent. 3 : 5-Dic~ZorotoZuenesuZphonanzide.-Sulphonation was readily effected in the ordinary way and the sulphonate converted into the sulphonic chloride, which crystallised from petroleum in large, thick prisms melting at 44-45', The sulphonamide crystallised from spirit in needles melting at 168-169'.

ISSN:0368-1645    

DOI:10.1039/CT9017901111

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

THE ESTERIFICATICJN OF 3-NITROPHTHALIC ACID. 1135 CXXL-The Esterification of %Niti*ophthalic Acidd By ALEX. MCKENZIE, Grocers’ Company Research Scholar. VICTOE MEYER’S rule for the ester formation of aromatic acids is of such general applicability that exceptions to it present certain points of interest. Such an exception is 3-nitrophthalic acid. Faust (Annulen, 1871, 160, 56) obtained a crystalline ethyl hydrogen ester by con- ducting the esterification in the cold, whilst a normal ester resulted as an oil on rise of temperature, Since, however, the product of the nitration of phthalic acid has been shown by 0. Miller to be a mixture of 3- and 4-nitrophthalic acidf, and is not homogeneous as Faust apparently supposed, mucn weight could not be attached to the observation of the latter investigator.The different behaviour of the isomeric nitro- phthalic acids on esterification by the hydrogen chloride method mas noted by Miller (Bey., 1878, 11, 1191 ; Anncden, lSS1, 208, 227), who points out that when the mixture resulting from the nitration of phthalic acid is directly esterified, the 4-nitrophthalic acid is converted into the normal ester, the 3-nitrophthalic acid, on the other hand, slightly into the normal ester, and mainly into the acid ester. V. Meyer and Sudborough (Ber.s 1894, 27, 3151) suggested that the presence of this normal ester might possibly be attributed to the prolonged action of the methyl alcohol and mineral acid causing slight decomposition of the 3-nitrophthalic acid into mononitrobenzoic acid, the melting point of the methyl ester of which agrees closely with that observed by Miller for the normal ester, Wegscheider and Lipschitz (Monatsh., 1900, 21, 787) have supplied experimental evidence for the invalidity of this hypothesis by hydrolysing the normal methyl ester produced on the esterification of 3-nitrophthalic acid by the sulphuric acid method, and by identifying the resulting compound as 3-nitro- phthalic acid.With regard to the explanations adduced to account for the devia- tions from the V. Meyer rule, Graebc’s observation that tetrachloro- phthalic acid formed an ethyl hydrogen ester when esterified by the hydrogen chloride method (AnnuZen, 1887, 238, 327), was attributed by V. Meyer and Sudborough (Zoo. cit.) to the probable existence of tautomeric forms, the acid esters of substituted phthalic acids being represented, €or instance, as C6HI<g$E and C6H4<:>0.Similarly, Graebe (Ber., 1900,33,2027) supposes that in the esterifica- tion of 3 : 6-dichlorobenzoylbenzoic acid, which is also an exception to the V. Meyer rule, the acid acts as the tautomeric oxyphthalide, thus ; RO OH \/ 4 H 21136 McKENZIE : THE ESTERIFICATION OF /C( OH)*C,H, c6c12\ >O + C2H5*OH = CO V. Meyer, as well as Wegscheider, assumes that the anhydride is the intermediate product, and that this is further acted on by the alcohol; for example, the acid ester of 3 : 6-dichlorophthalic acid (Graebe, Ber., 1900, 33, 2019) results according to the scheme : and when attempts are made to convert it into the normal ester, its comportment accords with the V.Meyer rule. Marckwald and the author (Ber., 1901, 34, 485) have recently separated the alcohols of fuse1 oil by converting them into the crystal- line P-acid esters of 3-nitrophthalic acid. Inactive 1-isoamyl-3-nitro- phthalic acid aud 1-d-amyl-3-nitrophthalic acid mere isolated, and the corresponding alcohols, isobutylcarbinol, (CH,),CH*CH2* CH,*OH, and I-methylethylcarbincarbinol, CH,*(C2H5)CH*CH2*OH, were ob- tained from them on hydrolysis. We noticed, in the course of the work, that (1) when 3-nitrophthalic acid was esterified by amyl alcohol by E. Fischer and Speier's method, the main product was the P-acid ester, but the a-acid ester and the normal ester were also formed, (2) when the alcohol was directly esterified by 3-nitrophthalic anhy- dride, the main product was the a-acid ester, the P-acid ester being also present.Wegscheider and Lipschitz (Zoc. cit.) have shown that when the acid is esterified in presence of sulphuric acid and methyl alcohol, the main product is the P-acid ester, but the normal ester is also produced under certain conditions. Direct esterification by the anhydride, on the other hand, was found by them to yield 90 per cent. of the a-compound. Isomeric acid esters of the type under consideration vary in electrical conductivity, and Wegscheider has shown this in several cases, for example, NO2 a-Ester ( K = 0 -2). NO, \/CO,CH, ()CO,H &Ester ( ~ = 1 ' 5 ) . In fact, Wegscheider bases his nomenclature of such compounds on the difference in conductivity, that ester with the smaller value for K being termed the a-ester (Monat~h., 1895, 16, 141, &c.).Of the two carboxyl groups in 3-nitrophthalic acid, the one in the ortho-position3-NITROPHTJTALIC ACID. 1137 relatively to the nitro-group is the ‘Lstronger ” of the two, and the stereochemical obstruction caused by it is more marked than that, caused by the other group in the 1-position, Therefore on esterification by the hydrogen chloride or sulphuric acid method, the P-acid ester is the main product. According to this view, both isomerides might be ex- pected to be formed, the relative amounts of which would depend on the difference between the carboxyl groups in the particular acid used. The present paper affords evidence for the formation of both isomerides on the esterification of an unsymmetrical dicarboxylic acid, a probability which has been repeated1.y suggested by Wegscheider (Monatsh., 1895, 16, 141 ; 1897, 18, 640 ; 1899, 20, 696 ; Oesterr.Chem. Zeit., 1901, 6 ; Ber., 1901, 34, 650). The formation of the normal ester on esterifi- cation by the sulphuric acid method was. also observed. Further, inactive 2-isoamyl-3-nitrophthalic acid and 2-d-amyl-3-nitrophthalic acid have been prepared and examined. For the preparation of 3-nitrophthalic acid, the method by nitration of phthalic acid (Miller, Annulen, 1881, 208, 225) is most convenient. On nitrating, care should be taken to observe just when the action begins, and at once to moderate i t by cooling, otherwise it proceeds too violently. The melting point of the acid used in the following experi- ments agreed with that of Miller.3-Niti*ophthaZic Anhydvide. The following was found a suitable means of preparation. Equal weights of the acid and acetic anhydride are gently heated with the free flame until all the acid dissolves, and then for five minutes longer to complete the reaction. When the solution cools, the anhydride quickly crystallises, and is drained off and washed with ether. It melts at 162’. A further quantity may be obtained from the mother liquor on removal of the ether and the bulk of the acetic anhydride. The method gives an almost theoretical yield. 2 -is0 Amy I-3-nitrophthab ic Acid. The corresponding P-acid ester, which yielded isobutylcarbinol, has already been described (Marckwald and McKenzie, loc. cit.).The a-compound was prepared by heating isobutylcarbinol (4.5 grams) with a 5 per cent. excess of nitrophthalic anhydride (9.4 grams) for 15 minutes on the water-bath, and then carefully for 5 minutes with the free flame. After addition of benzene to the hot solution, a finely crystalline crop of 8.5 grams separated on cooling, and when this was recrystallised several times from benzene i t melted a t 165-166’. On analysis :1138 McKENZIE : THE ESTERIFICATLON OF 0.5704, dried at 100' and dissolved in methyl alcohol, required 20.35 C.C. N/10 potassium hydroxide for neutralisation. C13H1506N requires 20.30 C.C. The ester is sparingly soluble in benzene and carbon tetrachloride, and is hydrolysed with much more difficulty than the P-isomeride. On theoretical grounds, the latter observation was to be expected, as the alcohol radicle in the a-ester is regarded as replacing the hydrogen of the stronger carboxyl group, and should therefore not be so easily detached as in the case of the /I-ester.2-d-AmyI-3-nitrophthc Acid. The corresponding p-ester has been described (Ioc. cit.). An acetone solution of it gave [a J:r + 6.5' (c = lo), and the I-amyl alcohol obtained from it had the rotation ay - 9-62' ; hence [ a]ip - 5.90'. The amyl alcohol used for the preparation of the a-ester was pre- pared by subjecting fuse1 oil (a, - 2 * 2 O , I = 2) to a modification of the Le Bel-Rogers' method, and then working up the product (a, - 6', I = 2) by treatment with 3-nitrophthalic acid (lac. cit.). A prolonged series of crystallisations yielded an ester with the rotation in acetone [ agf' + 5.9' for c= 10, but in this case the separation of the mixed crystals was not carried to the limit.The product, on hydrolysis, gave an alcohol with C Z ~ - 8-50' ( I = 2), which contained therefore 88.5 per cent, of I-amyl alcohol, This alcohol (9.8 grams) was heated with a 5 per cent. excess of nitrophthalic anhydride (20.5 grams) for 25 minutes on the water- bath, and then carefully with the free flame until the solution was clear. After treatment with benzene as before (p. 1137), 19.2 grams were obtained with the m. p. 156-158O and with the rotation in ace- tone solution [ a ] T + 2.2' for c = 8.3615. After recrystallisation from benzene, 17.9 grams (m. p. 157.5-158.5O) resulted, and a determination of the specific rotation in acetone solution gave the following result : I = 2, o = 8.256, a z + 0.37', [ a]": + 2.2".On analysis : 0-3945, dried at 100' and dissolved in methyl alcohol, required CI,H,,O,N 14.4 C.C. N/10 potassium hydroxide for neutralisation. requires 14.04 C.C. 0.1939 gave 0.0925 H,O and 0.3985 CO,. C,,H,,O,N requires H = 6.3 ; C = 55.5 per cent. Like the isomeric p-ester, this compound is beautifully crystalline. It dissolves at once in cold dilute ammonia solution, is very easily soluble in acetic ether or acetone, and easily in chloroform, but only I$ = 5.3 ; C = 56.0.3-NITROPHTHALIC ACID. 1139 sparingly in benzene or carbon disulphide. more difficulty than the P-ester. recrystallisation from benzene and from other solvents. It is hydrolysed with Its melting point was not raised on E~tter$cation.of AmyI AIcohoI 6y Nitrophthalic Anhydride. This experiment indicates the formation of a- and P-acid esters. An active amyl alcohol (33 grams, a 5 per cent. excess) with the rotation aD - 4.7' ( I = 2) was heated on the water-bath for 15 minutes with nitrophthalic anhydride (69 grams) until the mass became asolid paste, which was then cautiously heated with a free flame until the solution was clear. By treatment with benzene as before, and after recrystallisation of the resulting product from benzene, 55 grams were obtained ; this, on analysis, had the composition C,,H,,O,N. The specific rotation in acetone was [u]F + lalo (c= 8.1155). The pro- duct contained no normal ester, as it dissolved at once in cold dilute ammonia; it melted at 151-154", and an examination of the melting points of successive crops from benzene and other solvents showed that i t obviously presented a case of mixed crystals of the acid esters containing the a-compound in excess.The separation would have proved very tedious, and ma8 not in this case carried out. Systematic crys- tallisation of the benzene mother liquors yielded a product containing excess of the @ester, and crystallising from carbon disulphide in glassy, transparent prisms (m. p. 101-110'); a determination of its rotation in benzene gave [.ID + 5.9" for c = 3.5655. Ester$cation of AmyI AlcohoE by Nitrophthalic Acid. This experiment affords evidence for the production of a- and P-acid esters, and of the normal ester. The amyl alcohol used had the rotation uD - 6' ( I = 2), and contained therefore about 60 per cent, I-amyl alcohol.3-Nitrophthalic acid (89 grams) was heated on the xater-bath for 14 hours with amyl alcohol (178 grams) and sulphuric acid (26-7 grams). When the bulk of the mineral acid had been removed by washing with water, the amyl alcohol was separated by distillation under diminished pressure, and further esterified as before, in order to obtain a larger yield of crystalline esters. The alcohol removed after each esterification was markedly less laevorotatory than the original and this indicated that the active constituent was esterified more quickly than the inactive. The brown oil obtained from the two esterifications was warmed, and an excess of carbon disulphide added.After several hours, the crystals were drained off and washed with carbon disulphide. In this way, 80 grams of a mixture of the acid1 I 40 THE ESTERIFICATION OF 3-NITROPHTHALIC ACID. esters were obtained, from which 1-d-amyl-3-nitrophthalic acid may be separated (Zoc. cit.). From the carbon disulphide mother liquors, the carbon disulphide and the free amyl alcohol were removed by distillation in a current of steam. A calculated excess of sodium hydroxide was added to the residue, and the distillation in steam was continued until no more alcohol was observed to distil over. The residue in the flask, although alkaline, contained a heavy oil, which was separated, and proved to be the normal ester, and could only be hpdrolysed with difficulty. The amyl alcohol obtained from it by heating it with 33 per cent.sodium hydroxjde and then distilling in steam, weighed 22 grams, and had the rotation aD - 5.83" ( I = 2). For the formation of normal ester, compare Wegscheider and Lip- schitz (Zoc. cit,), and Graebe and Rostowzew (Ber., 1901, 34, 2107). Ester9cation of Methyl Alcohol 6y Nitrophthalic Anhydride. Nitrophthalic anhydride (38 grams) was heated on the water-bath under a reflux condenser for 2 hours with methyl alcohol (100 c.c.). After standing overnight, the alcohol was evaporated off, and a crystalline solid was obtained which was sparingly soluble in cold, but much more easily in hot water. A small portion of it dis- solved a t once in cold dilute ammonia, and therefore no normal ester was present. After one crystallisation from water, the air- dried substance weighed 40 grams, and a sample of it, dried at looo, melted very slightly between 138O and 145O, and mainly between 145O and 1 4 9 O . By repeated crystallisation, each time from much water, the melting point became very gradually sharper, whilst each crys- tallisation yielded glassy, prismatic needles, apparently uniform in crystalline form.The variations in melting point undoubtedly showed that the case was one of mixed crystals of the a- and P-acid esters, with the former in excess. The difficulty of separating the constituents of the mixture in such a case is exem- plified by the experience of Balbiano (Gaxxetta, 1876, 6, 229), and of Marckwald and the author (Zoc. cit.). The isolation of the a-compound was conducted by recrystallising the above product 25 times from water ; the progress of the separa- tion was observed by a determination of the melting point of each successive crop, dried a t looo. The sulphuric acid, in which the melting point tube was immersed, was kept in constant agitation, and the temperature, when nea.r the melting point, was not allowed to rise more than lo per minute.The points at which melting was just observable, and a t which the last trace of solid had disap- peared, were carefully noted by aid of a, lens. The melting pointsDERIVATIVES OF %NITROTOLY I,-4-HYDRAZINE. 1 14 1 were not corrected. Finally, 4 grams of the a-compound were obtained, the melting point of a portion of which, dried at looo, was 152-153". On analysis : 0.6237, dried in air, lost 0*0480 a t 105'. 05757 anhydrous substance, dissolved in methyl alcohol, required H,O = 7.7. C,H70,N + H,O requires H,O = 7.4 per cent. 25.7 C.C. N/10 potassium hydroxide for neutralisstion. C,H70,N requires 25.6 C.C. per cent. Wegscheider and Lipschitz (Monatsh., 1900,21 , 794), under different conditions from those just described, claim t o have obtained a 90 per cent. yield of the a-ester, and give its melting point as 144". On repetition of the esterification exactly under the conditions quoted by them, I was unable t o confirm their results. The phenomenon of mixed crystals was again evidenced. The a-ester was, however, isolated, and melted as before at 152-153'. On esterification of methyl alcohol by 3-nitrophthalic acid by the E. Fischer-Speier method and removal of the small amount of normal ester produced, a product was obtained which melting point determin- ations again indicated to consist of mixed crystals of the a- and ,@-acid esters. The separation of the p-ester was, however, not attempted. SECOND CEEMICAL INSTITUTE, UNIVERSITY OF BERLIN, AND JENNER INSTITUTE, LONDON.

ISSN:0368-1645    

DOI:10.1039/CT9017901135

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

DERIVATIVES OF %NITROTOLY I,-4-HYDRAZINE. 1 14 1 CXXII.-Deiivatives of 3-NitrotolyE-4-hydraxine. By FRANK GEO. POPE and JAS. MORTON HIRD. SOME years ago, one of the authors, in conjunction with J. T. Hewitt, described m-bromo-p-tolylhydrazine and its derivatives (Trans., 1898, 73, 174), from which it was thought that closed ring compounds might be produced by elimination of halogen from the nucleus and hydrogen from the side chain. A t the time, however, no satisfactory results were obtained, although by the action of heat on the anhydrous potassium salt of the pyruvic acid hydrazone, two substances, one being acidic in character and the other phenolic, were formed. Their nature mas not further determined at the time, and experiments are still being carried on in the hope of eliminating hydrogen bromide from the compounds.It has occurred to us that the corresponding nitrohydrazine might be more suitable for the formation of such closed rings, and experi-1142 POPE AND HIRD: DERIVATIVES OF ments are now being carried out in this direction, but as none has yet been brought to a perfectly definite conclusion, we think it advis- able to give a short account of the preparation and properties of the hydrazine and some of its chief derivatives. For the purpose of obtaining the hydrochloride of this hydrazine from m-nitro-p-toluidine, V. Neyer and Lecco's method (Ber., 1883, 16, 2976) was employed. The double tin salt of the hydrazine was freed from tin by hydrogen sulphide; on filtering off the precipitated tin sulphide and carefully evaporating the solution, the hydrazine hydro- chloride was obtained in orange-red plates or needles.The recrystal- lised salt melts and decomposes a t 190-191', and is soluble in water with slight decomposition. In aqueous solution, the salt shows the characteristic reduction of Fehling's solution, On analysis : 0.0872 gave 15.8 C.C. nitrogen a t 1 8 O and 744.5 mm. N = 20.36. C7H2,0,N,Cl requires N = 20.68 per cent. The hydrazine is obtained from a solution of the hydrochloride in water, by the addition of sodium acetate, as a dark red precipitate. This, after being dried over sulphuric acid and recrystallised from ether, separates in dark red tufts of needles melting a t l l O o . On analysis : 0.0949 gave 20.5 C.C. nitrogen at 1 9 O and 757 mm. N = 24.80.CtH90,N, requires N = 25.15 per cent. The base is very soluble in acetone, and moderately so in ether, ethyl acetate, chloroform, or benzene, but only slightly so in light petroleum. Pyruuic acid ntit.rotoZyZhydrazoe, N0,*C7H,*NH*N :C(CH,)*CO,H, is precipitated immediately on mixing aqueous solutions of the hydr azine hydrochloride and pyruvic acid as a chrome yellow, amorphous substance. This, when recrystallised from alcohol, melts a t 203' with decomposition. It is soluble in acetone, ether, ethyl acetate, benzene, or chloroform, but only slightly so in light petroleum. 0-1024 gave 16.1 C.C. nitrogen at 2 5 O and 747 mm. On analysis : N = 17.50. C,,H,,O,N, requires N = 17.72 per cent. The ethyl egter, NO,*C:H,*NH*N:C(CH,)*CO,C,H,, was prepared by boiling the hydrazone with its own weight of sulphuric acid and ten times its weight of absolute alcohol for 10 hours in a reflux apparatus.The mixture was then poured into dilute sodium carbonate solution, when the ester separated in yellow flocks, which, on crystallisation from alcohol, formed small, orange needles melting at 140'. On analysis :3-NITROTOLYL-4-HY DRAZINE. 1143 0.1353 gave 18*9 C.C. nitrogen at 34' and 768 mm. C,,H,,O,N, requires N = 15.85 per cent. Nitrot olylsemicarbaxide, NO, * 0, H, * NH*NH CO*NH,, is immediately precipitated on mixing aqueous solutions of the hydrazine hydro- chloride (2 grams) and potassium cyanate (0.81 gram) as a light yellow, sandy powder, This, when recrystallised from much hot water, in which it is only slightly soluble, is obtained in small, yellow needles which melt at 201' with decomposition, and are only slightly soluble in the usual solvents, N = 15.79.On analysis : 0.1449 gave 33.9 C.C. nitrogen at 25' and 751 mm. C,Hl,0,N4 requires N = 26-67 per cent, An aqueous solution of this Substance, on treatment with alcoholic potash in the cold, gives a deep violet colour, and if left to stand for some days, a crystalline precipitate is obtained. Salicylccldehyde nitrotolyzhydraxone, NO,*C,H,*NH*N:CH*C,H,*OH, was obtained in the following manner : 1-25 grams of salicylaldehyde were covered with water, and 2 grams of the hydrazine hydrochloride, dissolved in water, added ; the whole was then well shaken after the addi tion of excess of sodium acetate solution. A brilliant scarlet pre- cipitate was immediately produced ; this was recrystallised from benzene, in which it is very soluble, separating in the form of needles which melt at 226O.It dissolves only sparingly in ether, ethyl acetate, chloroform, or light petroleum. N=26*44. On analysis : 0°1083 gave 15.1 C.C. nitrogen at 20° and 737 mm. C14H1303NI requires N = 15-50 per cent. Furfuraldehyde nitrotolylhydraxone, NO,* C7H,* NH*N: CH*C,OH, was obtained in an analogous manner, giving a bright scarlet precipi- tate, which was recrystallised from hot alcohol, forming red needles melting at 165-1664 It dissolves easily in the ordinary organic solvents except ether and light petroleum, N = 15.46. On analysis : 0.1285 gave 19.6 c,c. nitrogen at 15O and 755 mm. C1,H,,03N3 requires N= 17*14 per cent.Benxaldehyde nitrotolythydrccxone, NO,*C,H,*NH*~:CH'C,H,, was also obtained in the same manner, and crystallised from benzene in rod needles which melted at 166'. It is only slightly soluble in light petroleum or acetone. N = 17-75. On analysis : 0.0996 gave 15.2 C.C. nitrogen at 26' and 759 mm. C14H1302N3 requires N = 16-47 per cent. P ~ n y l n ~ ~ o t o ~ ~ ~ t h ~ o s e r n ~ c a r ~ a x ~ ~ e , NO,*C7H,*NH0NH*CS*NH*~,H~, was prepared by mixing ethereal solutions of the free hydrazine and N = 16-74,1144 HENRY : THE CONSTITUENTS OF THE SANDARAC RESINS. phenylthiocai bimide in molecular proportion, and allowing the solu- tion to stand for about half an hour. When recrystallised from ether, i t gave tufts of golden yellow needles melting and decompos- ing at 188'. On analysis : Cl4H1,O,N,S requires N = 18.54 per cent. NO, * C7H, NH*NH* CS*NH C,H,, was prepared in a similar way, and formed yellow needles melting a t 168-170" when recrystallised from dilute alcohol. 0.1120 gave 21 C.C. nitrogen at 28' and 759 mm. C,lHl,O,N,S requires N = 21 5 2 per cent. Acetylnitrotolylhydrazine, NO,*C~H,*NH*NH*CO*CH,, was prepared by boiling the hydrazine with an excess of glacial acetic acid for 4 hours in a reflux apparatus, pouring the product into water, filter- ing, washing with cold water, and recrystallising from hot water. It formed small, golden needles melting at 161O. 0*1010 gave 16.8 C.C. nitrogen at 1'7' and 750 mm. Nityot olylallylt hiosemkarbazide, N= 18.91. On analysis : N = 21.0. On analysis : 0.1012 gave 17.5 C.C. nitrogen at 19' and 768 mm. We hope t o be able to communicate further results as t o the N=20.25. CgH1,O,N, requires N = 20.10 per cent. behaviour of certain of these compounds shortly. EAST LONDON TECHNICAL COLLEGE.

ISSN:0368-1645    

DOI:10.1039/CT9017901141

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1144 HENRY : THE CONSTITUENTS OF THE SANDARAC RESINS. CXXII1.-The Constituents of the Sandarac Resins. By THOMAS ANDERSON HENRY, D.Sc. (Lond.), Salters’ Company’s Research Fellow in the Laboratories of the Imperial Institute. THE sandarac of commerce is derived from the plant Callitris quadri- valvis which occurs in the plant family Cupreesinece, a subdivision of the Conyeerce. Like most plants of this order, the various species of Callitris secrete an oleo-resin, which at certain seasons of the year exudes from the stem, and by evaporation of a portion of its contained volatile matter forms small, hard masses of resin technically known as ‘( tears.” It is in this form that sandarac occurs in commerce, the ‘‘ tears ” being long and narrow, having a glassy fracture, and a pun- gent, aromatic, and slightly bitter taste.The resin is employed in the manufacture of some of the finer kinds of spirit varnishes, and in the form of a powder for dusting on the surface of parchment to increase its absorptive power for ink.HENRY : THE CONSTITUENTS OF THE SANDARAC RESINS. 1145 There also appears on the market from time to time a similar resin, which, since it is exported from Australia, is commonly known as “ white pine resin,” or ‘‘ Australian sandarac.” This substance is the natural exudation product of Callitris vermcosa, and differs from the common sitndarac chiefly in the larger size of its “tears” and its smaller solubility in alcohol, It was with the object of comparing the constituents of these two resins that the present investigation was undertaken.The chemical constituents of the resins of the various species of Pinus have been the subject of many investigations, but the less known members of the Conifera have been somewhat neglected in this respect, so that the literature of the present subject is meagre. The first important paper dealing with the chemistry of sandarac is that of Johnston (Phil. Trans., 1839, 129, 239), who asserts that the resin contains three acids differing in their solubilities in alcohol and in those of their potassium salts in alcoholic potasb. These acids were isolated in the following way. The resin was exhausted with alcohol, leaving an insoluble, yellow, amorphous powder, soluble in ether and having a composition represented by the formula C,,H,,O,. This the author calls A resin, The alcoholic extract was then treated with solid potash, whereby an insoluble potassium salt was obtained.This, on solution in water and addition of ,hydrochloric acid, gave B resin, which is similar in appearance to the A resin, but is soluble in alcohol, and has a composition represented by the formula C40H,10G. The portion soluble in alcoholic potash gave, on regeneration wit’h acids, a mixture of two resins, of which one, soluhle in alcohol and on combustion giving numbers corresponding with those required for the formula G40H300G, is named C resin; whilst the other, insoluble in alcohol, is regarded as identical with A. No attempts were made by the author to crystallise these substances, nor were any well-defined derivatives obtained from them.The only other paper of interest is that of Tschirch and Balzer (Arch. Phama., 1896,234,291). These authors adopted a slight modifica- tion of Johnston’s method for the separation of the constituents, namely, they dissolved the resin in aqueous potash, and to this solution added solid potash, so precipitating an insoluble potassium salt, from which was regenerated, by solution in water and addition of hydrochloric acid, an amorphous resin which was named sandaracolic acid. This substance is said to be obtained in a crystalline condition by allowing its alcoholic solution to stand for a long time. The crystals melted at 140°, and on combustion numbers were obtained agreeing with those required by the formula C,,H,G07. The molecular weight was determined by Raoult’s freezing point method, and the curious results obtained by the authors are t,ahulated below.I n calculating &.I from1146 HENRY: THE CONSTITUENTS OF THE SANDARAC RESINS. the experimental data, evidently some arithmetical error has been made by the authors, as is shown by the recalculated values of M given in the tabular statement (C,,H6,07 requires M = 718). I I I Molecular l and Balzer. (phenol). 660 645 690 Molecular weight recalculated. 66 120 638 Such arithmetical errors frequently occur throughout the paper, and will be pointed out as they arise. By titration experiments with normal potash, the authors find that this acid is monobasic, yet they assign without comment to the copper salt, obtained by double decom- position between copper sulphate and the sodium salt, a formula representing it as that of a dibasic acid, namely, C45Hs407C~.The silver salt was also prepared by the addition of excess of ammonia to sandaracolic acid and the further addition of ammoniacal silver nitrate solution. On standing for some weeks, this solution deposited a precipi- tate which was found to contain 12.84 per cent. of silver ; C4,H,,0,Ag requires 13 per cent. By the action of acetic and benzoic anhydrides, monoacetyl and monobenzoyl derivatives respectively were obtained, but only in an amorphous condition. By the action of hydriodic acid in Zeisel's apparatus, evidence of the existence of a methoxyl group in the acid was obtained, whilst oxidation with nitric acid gave picric and oxalic acids. Fusion with potash gave a substance resembling resor- cinol.From the potassium salt soluble in excess of potash, was isolated by the addition of hydrochloric acid, a second resin, to which the name callitrolic acid was given. This acid was with difficulty obtained in a crystalline condition by conversion into its amorphous lead salt and regeneration by . sulphuretted hydrogen. The crystallised acid melted at 248O, and, on combustion, the following results were obtained : C,,H,,O, requires, according t o the authors' calculations, C = 7'7.3, H=8*43 per cent. I n reality, this formula requires C = 78.6, H = 8.4 per cent., and the results obtained by the authors are better represented by the formula C62Hs008, where C = 78.15, H = 8.40 per cent. The molecular weight was determined by the freezing point method, and found to agree with that required by the formula C6,Hs4O,.The (i) C = 77.79, H = 8.63 ; (ii) C = '77.58, H = 8-30.HENRY: THE CONSTITUENTS OF TRE SANDARAC RESINS. 1149 same carelessness in calculation is shown here, thus : 22.14 grams of phenol, containing 0.331 gram of the acid, gave a depression 0.129 According to the authors, this corresponds to a molecular weight 952 ; in reality, the calculated value is 921, but this is sufficiently near that required by the formula C,5H,,0, to be within experimental error. Callitrolic acid was also found to be monobasic, yet the authors assign to its copper salt the formula CgbHs2OSCu, which is that of a salt of a dibasic acid. On subjecting the crude resin to steam distillation, a quan- tity of a brown oil having an odour of pine trees was obtained, but was not further examined.Since the appearance of the above paper, Tschirch, in a note appended to a paper on another subject, mentions that he has isolated from sandarac a new crystalline acid by shaking an ethereal solution of the resin with sodium carbonate (Dieterich, Analyse der Hurx, Berlin, 1900), but no further information regarding this acid has been published. It will be convenient to include in this account of previous work on this subject a short re’sum8 of the work so far accomplished on pine resins, since, as will be seen later, the constituents of sandarac bring it into close relation with this class. From commercial colophony there have been isolated by various workers, sylvic, sylvinic, isosylvinic, pimaric, p h i c , and abietic acids, but the researches of Liebermann (Ber., 1884, 17, 1884), Haller (Ber,, 1885, 18, 2165), Maly (Annulen, 1869, 149, 115, 161, 244), and espe- cially of Mach (Xonatsh., 1893, 14, 186; 1894, 15, 627), show clearly that most of these substances are merely impure forms of abietic acid.Mach examined a large number of specimens of American and French colophony and of ‘‘ galipot,” and in each case he was only able to iso- late abietic acid, CIgH,,O,. On the other hand, Vesterberg, in his researches on the constituents of ‘‘ colophonium de Bordeaux ” (Bey., 1885, 18, 3331; 1886, 19, 2167; 1887, 20, 3251), found that this resin contained two isomeric crystalline acids of the formula C20H3002, to which he gave the names d- and I-pimuric acid8.Whilst Mach could not obtain these substances from the Bordeaux colophony now obtainable in commerce, he was able, by an examination of a specimen of d-pimaric acid supplied to him by Vesterberg, to confirm the results of the latter. These results are perhaps to be explained on the assumption that American colophony has, in European commerce, almost replaced the French product, whilst the American ‘‘ thus ” is now commonly sold in place of ‘‘ galipot.” I n a more recent investigation of Bordeaux turpentine by Tschirch and Bruenig (Chem. Centr., 1900, ii, 1270), it was found that this resin contains two crystalline acids, pimarinic acid (m. p. 1 14-1 1 8 O ) and pimaric acid. The latter, isolated by treating the resin with soda1148 HENRY: THE CONSTITUENTS OF THE SANDARAC RESINS.solution, was optically inactive, whilst the pimaric acid, isolated from a specimen of Bordeaux colophony by crystallisation from alcohol, was strongly laevorotatory. The optical inactivity of the first- mentioned specimen of acid is accounted for by the authors on the assumption that racemisation occurs with the conversion into the sodium salt. These results are in direct opposition t o those of previous workers-thus, Vesterberg used the sodium salts of d- and I-pimaric acids as a means of isolating and purifying these substances, and the products so obtained were optically active. Further, it should be pointed out that, although the authors give a certain amount of evidence for the statement that pimarinic acid is a new substance, they content themselves as regards pimaric acid with the assertion that they obtained it, and give no details as to how they identified it.Since no account of an inactive pimaric acid has, so far, appeared in chemical literature, it is curious that no attempt was made to charac- terise this substance wben opportunity offered. Attention should also he drawn to the work of :Bruylants on the destructive distillation of colophony (Ber., 1875, 8, 1463 ; 1878, 11, 447). This author obtained in this way ethylene, propylene, and a,mylene, and by the destructive distillation of calcium pimarate, similar compounds, together with methyl ethyl ketone, diethyl ketone, toluene, dimethylbenzene, terebene, and diterebene. He infers from these observations that the constitution of pimaric acid may be repre- sented by the formula which is that of a carboxyl derivative of a diterpene.I n a similar manner, Bischoff and Nastvogel (Ber., 1890, 23, 1921) cjbtained, by destructively distilling colophony in a vacuum, an oily hydrocarbon boiling at 216-225', and a volatile resin to which they give the name isosylvinic anhydride, since, on treatment with sodium hydroxide, it gave the sodium salt of an acid isomeric with sylvinic acid, C20H3,,02. To the oily hydrocarbon which they regarded as identical with the colophene of Deville (Ann. Cl~im. Phys., 1840, [ii], 75, 37) and Riban (Ann. Chim. Phys., 1875, [v], 6, 40), they ascribe a constitution, which is that of it condensed dihydrocymene, whilst they further represent isosylvinic acid as a carboxy-derivative of colophene, and the anhydride as formed by the condensation of two molecules of the acid.It will be seen that such a formula closely resembles that suggested by Bruylants. Similar evidence of the aromatic character of the nucleus of the acid of colophony is given by Ciamician, who ob- tained, by distillation of this resin with zinc dust (Be?*., 1878, 11, 269), such substanccs as toluene, naphthalene, methylnapkthsiene, and methyl-HENRY: THE CONSTITUENTS OF THE SANDARAC RESINS. 1149 anthracene. Further, Wallach and Rheindorff (Amzalen, 1892, 271, 285) find that colophony, on destructive distillation, yields pinene and dipentene. EXPERIMENTAL. Extraction of the Volatile Oil. The crude resin was dissolved in alcohol, and the solution made alkaline by the addition of alcoholic potash in slight excess.The alcohol was then removed by distillation, the residual semi-sdid mixture of potassium salts dissolved in water, and the solution shaken out with ether. Preliminary experiments having shown that the volatile oil of the plant consisted only of hydrocarbons, the ethereal solution so obtained was next dried over solid potasb, which removed, besides water, a small amount of resinous matter. The ether was then removed by distillation, and the residue fractionally distilled, I n general, it was separated into three portions, having the following range of boiling points : l50-l8O0, 180-220°, and 220-280'. From the first of these, a large fraction boiling from 150-160° could be obtained, which on redistillation over metallic sodium gave a portion boiling from 152-159'.The fraction 180-220' evidently was a mixture, but it was found impossible to get even a partial separation of its constituents, since on distillation the temperature rose fairly rapidly and regularly between the two limits mentioned. The fraction 220-280', on rectification over metallic sodium, came over mostly from 260-280' as a slightly viscous, colourless oil, having an odour faintly recalling that of peppermint. With the small quantities of volatile oil obtain- able, it was impracticable to attempt by further fractionation to obtain purer products than these two fractions. Their examination was therefore proceeded with, Fraction 6oiling between 152' and 159'. This fraction was a colourless liquid with a pleasant, pine-like odoiir.Its density a t 15'/15' was 0.8588 [pinene 0*85S6]. Determinations of the optical activity of the fraction in a 100 mm. tube with a Lament's polarimeter, using sodium light, gave + 18'27' as the mean of ten observations, whence [a], + 21'30'. Action of Nitrosyl Chloride.-To a few C.C. of the fraction the same quantity of amyl nitrite was added, and sufticient glacial acetic acid to form a clear solution, which was then cooled by immersion in a mix- ture of sodium sulphate and hydrochloric acid. To the solution was added, drop by drop, strong hydrochloric acid so long as a blue colour was produced, which disappeared on cooling and shaking. After a few minutes, a crop of crystals separated. These were removed by VOL.LXXIX. 4 11150 HENRY : THE CONSTITUENTS OF THE SANDARAC RESINS. filtration, and recrystallised by addition of methyl alcohol to their chloroform solution. The substance so obtained formed silky masses of minute needles melting at 103' when heated slowly. For purposes of comparison, a specimen of pinene nitrosyl chloride was prepared from commercial turpentine by the method described above. This presented a similar appearance to that obtained from sandarac oil, and melted at the same temperature under the same conditions, Preparation of the Nitro~i~ei.idide.-The nitrosyl chloride of the hydrocarbon was dissolved in a little alcohol, and a slight excess of piperidine was added to the solution, which was tben warmed on the water-bath for a few minutes.To the mixture, water was added, causing the precipitation of a heavy, oily liquid. The excess of water was poured off, and the oil dissolved in alcohol and set aside. After several days, a small quantity of a substance crystallising in needles and melting at 1 18', after recrystallisation from alcohol, was ob- tained. A specimen of pinene nitro1 piperidide, obtained in like manner from pinene nitrosylchloride, melted a t 118'. The fraction of lower boiling point from sandarac oil is therefore composed chiefly of d-pinene, Fraction 6oiling hetween 260' and 280O. This portion of the volatile oil, when freshly distilled over metallic sodium, is a colourlese, somewhat viscous liquid, but on standing it slowly assumes a greenish colour and shows slight signs of resinifi- cation.From its boiling point and general behaviour it was apparently a sesquiterpene or a diterpene, and further examination showed the latter supposition was most prcbably correct, A determination of the specific rotation in a 100 mm. tube, using sodium light, gave +5l042' as the mean of ten observations, whence [a]= + 5 5 O . The refractive index was determined by meaps of an Abbe refracto. meter and gave p= 15215 as the mean of ten observations. On analysis, the following result was obtained : 0.1237 gave 0.400 CO, and 0.128 H,O. A determination of the vapour density by Victor Meyer's method, using anthracene vapour as the heating agent, gave the molecular weight = 262 ; C,,H,, requires 272. Ethereal solutions of this hydrocarbon do not absorb hydrogen chloride, but they decolorise bromine with evolution of hydrogen bromide.Its density at 1 5 O / 1 5 O was 0,9386. The oil is dextrorotatory. C=88*1; H = 11.4. C,,H,, requires C = 88.3 ; H = 11.7 per cent.HENRY: THE CONSTITUENTS OF TEE SANDARAC RESINS. 1151 A satisfactory bromine derivative has not been obtained, the product being an oil which does not crystallise from solvents or become crys- talline when kept at low temperatures, On heating, even in a vacuum, it decomposes, giving resinous products, so that no method has been found of obtaining it in a pure state. The hydrocarbon does not combine with either nitrosyl chloride or nitrogen trioxide, In several attempts to prepare such derivatives by the usual methods no combination occurred, and the unaltered sub- stance was recovered at the end of the experiments.On adding strong sulphuric acid, drop by drop, to a solution of the hydrocarbon in glacial acetic acid, a deep violet colour is produced, which disappears on warming. The physical constants of this oil Bhow that it does not belong to the class of sesquiterpenes, but probably to the diterpenes. The properties of the latter class of substances are so far but imperfectly known. The constants given in the following table are those ascribed to the few diterpenes which have been isolated. For convenience of comparison, the constants usually characteristic of the sesquiterpenes are also added : Sesquiterpenes.. . . Diterpenes.. .. . , , . . Sandarac hydro- carbon . . . . # . . . . , . Relative density. 0*9001-0'918 0.938 0.9386 Vapour 1 Refractive density, I index.B. p. 240-260" 260-315 270-280 Action of HCI. Forms additive No action. No action. products. It will be seen on comparing the constantfi of these various sub- stances as given in the table that the characters of the hydrocarbon of high boiling point of sandarac oil are in general agreement with those of the diterpenes, and that it must be regarded as a member of this class of compounds. lnactive Pimaric Acid. The mixture of potassium salts of the resin acids, after treatment with ether for the removal of the volatile oil, was warmed to remove the dissolved ether, and to the aqueous solution a 20 per cent. solution of potash was added until no further precipitation occurred, The slimy precipitate rapidly settled to a semi-solid mass, from which the supernatant liquid could be readily poured off.The precipitated potassium salt was then dissolved in water, strong hydrochloric acid added in excess, and the semi-solid mixture poured upon a calico filter, mashed free from acid, and dried in a current of warm air, When 4 1 21152 HENRY: THE CONSTITUENTS OF THE SANDARAC RESIh'S. quite free from moisture, it was treated with 90 per cent. alcohol, when it was found that a considerable portion of the resin was no longer soluble in that medium. The insoluble matter was filtered off, the filtrate made alkaline with alcoholic potash, and the solvent re- moved by distillation. With the residue, the precipitation of the potassium salt and the regeneration of the resin, as already described, mas repeated until a resin quite soluble in alcohol was obtained.If t o this alcoholic solution of the purified resin sufficient water be added to produce a slight turbidity, and the mixture be set aside for several days, a crop of crystals is obtained which when recrystallised melt at 1 7 1 O . It was found more expeditious, however, to proceed in the following way. The alcoholic solution of the resin was treated with alcoholic soda and the solvent removed by distillation. The residual sodium salt was dissolved in water, and sufficient 10 per cent. aqueous sodium hydroxide added to cause a Considerable precipitate to form. This mixture was then warmed on the water-bath until solution occurred. On cooling, a precipitate of the sodium salt slowly formed, which, when examined by aid of a lens, was found to consist of minute needles, This sodium salt can be recrystallised in the same way.From this recrystallised salt the acid was then obtained by adding hydrochloric acid to its aqueous solution, filtering off the precipitate, and after washing and drying it, dissolving in alcohol and adding sufficient distilled water to render the solution faintly turbid, From this solution there separated in a few hours a colourless, crystalline substance, which, after recrystallising once or twice in the same manner, melted constantly at 171'. The pure substance can also be prepared without the intervention of the sodium salt by taking the purified resin left after removal of the alcohol by distillation and distilling under 10-20 mm.pressure. Under these conditions, the residue distils easily and the temperature rises rapidly to 265' under 11 mm. pressure, and remains constant until the whole has passed over, condensing at first as a white, crys- talline sublimate, and later, owing to the increasing temperature of the receiver, as a very viscous resin. A little care has to be exercised in carrying out this operation, as the solid acid is rather liable t o block up the exit tube of the flask from which it is being distilled. The distillate obtained is at the ordinary temperature a vitreous, yellowish sdid which can be left for months without showing signs of crystallisa- tion. I f , however, a little 70 per cent. alcohol be added to it, crystals immediately begin t o form round the edges, and the whole mass be- comes warm and crystallises rapidly.On recrystallisation, this acid melts at 171°, and is in every way similar to t h a t obtained by the first-mentioned method. It crystallises in spreading rosettes of flat.HENRY: THE CONSTITUENTS OF THE SANDAEAC RESINS. 1153 tened needles, is soluble in alcohol, ether, chloroform, or acetone, insoIuble in water or petroleum, and slowly dissolves when warmed with aqueous alkali solutions. When a little is dissolved in a few drops of chloroform and about 1 C.C. of acetic anhydride added, the addition of a drop of strong sulphuric acid causes the formation of a transient pink coloration. This reaction is a convenient means of distinguishing the acid from abietic acid, which gives, under the same conditions, a deep purple colour fading into olive green.The crystalline acid prepared in any of the three ways described is not optically active in alcoholic solution. Combustions of the substance dried at 100' gave the following results : 0.1280 gave 0.374 CO, and 0.1083 H,O. C = 79.6 ; H= 9.3. 0.1638 ,, 0.4745 COa ,, 0,1413 H20. C = 78.9 ; H = 9.5. C,,H,,O, requires C = 79.4 ; H = 9.9 per cent. Combustions of the non-crystalline distillate were also made in order to ascertain whether this substance might not be the pimaric anhydride which has been asserted to exist. 0.1647 gave 0.4792 CO, and 0.1497 H,O. C = 79.41 ; H = 9.96. C40H5803 requires C = 81.9 ; H = 9.8 per cent. C,,H,,O, ,, C = 79.47 ; H= 9.9 ,, This result shows that the distillate is merely pimaric acid in an amorphous form.The basicity of the acid was determined by titration of the aIcoholic solution of the acid with decinormal soda, using phenolphthalein as indicator. 0.0902 required 3.5 C.C. N/lO NaHO; whence 40 grams NaHO neutralise 301 grams of acid. Salts of Inactive Pirnaric Acid.-The sodium and potassium salts are easily obtained by boiling the acid with excess of solution of the alkali. On cooling, the salt crystallises out in microscopic needles. The silver salt was prepared by the addition of silver nitrate solu- tion to an aqueous solution of the sodium salt of i-pimaric acid. It is an amorphous white powder which is only slowly affected by light, showing merely a slight purple coloration even after several weeks' exposure. C,,H,,O, = 302.0.0445 gave 0.011'7 Ag. Ag = 26.2. 0.1454 ,, 0.0384 Ag. Ag= 26.3. C,,H,,O,Ag requires Ag = 26.4 per cent. Ethyl Ester.-When the silver salt of pimaric acid is added to ethyl iodide, a deep purple-red solution is formed, which becomes colourless on addition of alcohol, silver iodide bebg precipitated. The residue1154 HENRY : THE CONSTITUENTS OF THE SANDARAC RESINS. left after removal of the solvent cannot be crystallised, but can be distilled at 280-285O under 11-12 mm. pressure. It is a slightly yellowish, hard resin. Comparison of Abietic and Inactive Pimaric Acids. As considerable difficulty has been found by previous workers in distinguishing between abietic and d- and I-pimaric acids, it was thought advisable to prepare specimens of abietic and d-pimaric acids for comparison with the acid obtained from sandarac resin, Abietic acid was easily obtained by the solution of colophony, de- rived from Pinus excelsa grown in India, in 90 per cent, alcohol and the addition of sufficient water to render the solution turbid.After a few days, a large crop of colourless crystals was obtained, These were recrystallised in the same way, and the recrystallisation repeated until the substance melted constantly at 162' [the melting point of abietic acid is 1 5 2 O (Mach), or 165' (Maly)]. The substance crystallises when pure in broad laminae, which are colourless and possess a brilliant lustre. The sodium salt was prepared by neutralisation of an alcoholic solution of the acid with normal soda. To the liquid so obtained, sufficient normal soda solution was added to precipitate the sodium salt, which was then collected, dried, and recrystallised from dilute soda, forming masses of minute needles.The silver salt was prepared from the latter by double decomposition in the usual manner. It is a white, amorphous substance. On analysis, it gave the following result : 0.0564 gave 0.0158 Ag. Ag=28.01. As has already been pointed out, Mach, in his recent investigation of the pine resins, showed that it was not possible to isolate d-pirnaric acid from the '' galipot " or French colophony of commerce. Recourse was therefore had in the present instance to Burgundy pitch, which is generally supposed to be made from the oleo-resin of Pinus maritima, but from three specimens examined only one and the same acid melting a t 161°, identical in all respects with that obtained from the resin of P i w s excelsa, could be isolated ; thus the silver salt, prepared as already described, gave the following result on analysis : C,g€1270,Ag requires Ag = 27.4 per cent.0.046 gave 0.0126 Ag. Ag = 27.39. C,,H,,O,Ag ?, Ag=26*4 9 , The attempt to prepare d-pimaric acid was therefore abandoned.HENRY: THE CONSTITUENTS OF THE SANDARAC RESINS. 1155 Melts at 171". Optically inactive. Crystallises in needles. A solution in chloroform and acetic anhydride gives a pink colour with concentrated sulphuric acid. Distils unchanged a t 265" under 11 nim. prcssure. The differences between the pimaric acid isolated from sandarac and abietic acid may be grouped thus :- Melts a t 161".[a]= +66". Crystallisis in lamins. A solution in chloroform and acetic anhydride gives a violet colour fading t o olive green with concentrated sulphuric acid. Distils unchanged a t 259" under 20 mm. pressure. I Inactive pimaric acid, C20H3002. Abietic acid, C,SH,,02. Action of Bromirte.-When a chloroform solution of bromine is gradually added to pimaric acid dissolved in the same solvent, the bromine is absorbed, and no hydrogen bromide is formed until the equivalent of two atoms of bromine per molecule has been added. On removing the chloroform by spontaneous evaporation, an oily substance is left, which, when dissolved in hot alcohol, deposits a colourless, granular bromine derivative on cooling. This substance has so far resisted all attempts to crystallise it.After heating for 20 minutes at 200', a considerable proportion of the acid was recovered unchanged, whilst only resinous products were formed from the re- mainder. Action of Hydriodic Acid,-When the acid is heated in sealed tubes a t 200-210' for 4 hours with excess of fuming hydriodic acid, it is completely reduced, forming an oily hydrocarbon. The product was made alkaline, when a small amount of iodoform was precipitated. The mixture was then shaken with ether, the ethereal solution separated, dried over solid potash, and the solvent removed by distillation. The brownish, oily residue was then distilled under 11-12 mm. pressure, and the fraction boiling between 170" and 190°, constituting about 90 per cent. of the whole, collected. This was then distilled over sodium, and after repeating this treatment twice, the oil boiled almost entirely between 180' and 185' under 11 mm.pressure. I t forms a faintly yellow, oily liquid with a bluish fluor- escence and has an odour recalling that of the crude higher paraffins. Its density at 15'/15O is 0.967. It is optically inactive, rapidly resinifies on exposure to air, decolorises bromine in ethereal solution, and does not absorb hydrogen chloride. It decomposes slightly when distilled under atmospheric pressure, The acid is not attacked by fused potash. On combustion, the following result was obtained :1156 HENRY: THE CONSTITUENTS OF THE SANDARAC RESINS. 0.123'7 gave 0.406 00, and 0,128 H,O. C = 88.9 ; H = 11.5. C,oH,, requires C = 88.3 ; H = 11.7 per cent.Tbe refractive index for sodium light was determined, using a small, hollow prism of refracting angle 61"25'. The angle of minimum deviation was found as the mean of ten observations to be 40'53', whence p = 1.5254. This hydrocarbon is apparently identical or isomeric with that obtained by Liebermann, Haller, and Vesterberg (Zoc. cit.), by re- duction of the d-pimaric acid of '' Bordeaux colophony " with hydriodic acid. It was suggested by Liebermann, who assigned to it the formula C2,H,2 or C20H34, that i t mas probably identical with the colophene (or colophene dihydride) obtained by Deville (Zoc. cit.) by the action of concentrated sulphuric acid on turpentine. For this substance, the name 6' dicamphene," as more suitably indicating its origin, has since been suggested by Armstrong and Tilden (Trans., 1879, 35, 733).A specimen of '' colophene " was prepared by the addition of strong sulphuric acid to turpentine in the proportion of 1 : 5. The volatile hydrocarbons were removed, as recommended by Armstrong and Tilden, by steam distillation, and the residual emulsion shaken with ether to remove the colophene. This solution was dried, the solvent removed in the usual way, and the residue distilled under 10-14 mm. pressure. A considerable amount of hydrocarbon came over below 100' ; the boiling point then rose rapidly to 190' and remained constant. The portion boiling in the neighbourhood of 190' was collected and redistilled over metallic sodium, when i t boiled constantly at 190' under 12 mm. pressure. This distillate is, however, not quite pure, as it always has a slight odour of camphene and of some sulphur com- pounds, which even repeated distillation over sodium fails to remove.On redistillation, a few drops of distillate were obtained before the tamperature became constant (206' under 35 mm. pressure), but the amount was not more than 0.1 per cent. of the whole. The obser- vations of Armstrong and Tilden (Zoc. cit.) seem to indicate that this substance cannot be distilled even under diminished pressure, but there seems t o be no difficulty in so distilling it if the pressure be sufficiently diminished. The purified substance is a viscous, slightly yellowish oil, having a camphoraceous Gdour which becomes somewhat pungent when warmed. I t decomposes slightly when heated under the ordinary pressure, but is not decomposed even at 150' in sealed tubes.The refractive index for sodium light was determined, using a small, hollow prism of refracting angle 61'25'. The angle of minimum deviation was found as the mean of ten observations to be 40°49', whence F = 1.5136. Its density at 15'/15' is 0.931.HENRY: THE CONSTITUENTS OF THE SANDARAC! RESINS. 1157 Relative density. I A comparison of the properties of colophene and the hydrocarbon obtained by the reduction of pimaric acid shows clearly that these two substances are not identical, Refractive index. 11 :;,: ;zt&e. I--- I - I _ - 180-185 Colophene . . , . . , , . , . . . . , . . . . . . . ' ' 1.5136 Saiiclarac hydrocarbon.. ,. . , . . 0.967 1 1.5254 0.931 Further, colophene is only slightly volatile with steam, whilst the sandarac hydrocarbon can easily be distilled in this may.The new hydrocarbon is also fluorescent, whilst colophene does not possess this property. Action of Nitric Acid.-The acid is but slightly attacked, except by hot concentrated nitric acid, when i t is converted into oxalic acid. Oxidution by Potassium Permanyanate.-When solution of potass- ium permanganate is added to an aqueous solution of the sodium salt of pimaric acid, decolorisation quickly occurs. The addition of the reagent was continued until the t i n t remained permanent for 4 hours. The solution was then filtered from manganese dioxide, and made acid by the addition of dilute sulphuric acid. A considerable amount of resin was precipitated containing some unchanged acid ; this was filtered, and the filtrate distilled with steam.The distillate was distinctly acid. It was neutralised by addition of caustic soda solution evaporated t o a small bulk, and silver nitrate solution was added t o it. After a few minutes, a crystalline precipitate formed. This was collected and-analysed, with the following result : 0.0105 gave 0.0067 Ag. The volatile acid was therefore acetic acid. The liquid, after distillation with steam, mas shaken out with ether, the ethereal solution separated, dried over calcium chloride, and the solvent distilled off, leaving an oily residue, which, after standing for several days with occasional stirring, deposited a small quantity of minute needles. The substances melted at 260°, gave a buff- coloured bromo-componnd with bromine water, and its aqueous solution was acid to litmus paper.A sufficient quantity of this substance has not yet been obtained for i t s complete identification, but its properties are similar t o those of trimellitic acid (m. p. 262O), which has already been found to occur among the oxidation products of crude pine resin. Ag = 63.8. C,H,O,Ag requires Ag = 64.4 per cent.1158 HENRY : THE CONSTITUENTS OF THE SANDARAC RESINS. Callitrolic Acid. This is the name given by Tschirch and Balzer to the acid whose potassium salt is soluble in excess of an aqueous solution of potash, but it is used in this paper to denote the second resin acid of sandarac. When the strongly alkaline solution of the potassium salt of callitrolic acid, obtained during the isolation of pimaric acid, is acidified with concentrated hydrochloric acid, almost the whole of the resin precipitated is insoluble in alcohol.This precipitate was boiled with alcohol until nothing more dissolved, and then treated with alcoholic potash, in which it dissolved completely. The solvent was removed by distillation, the residue dissolved in water, and more potash added. It was found that by slowly concentrating this liquid the potassium salt could be precipitated in fractions, the later fractions being nearly free from colour. These were collected, dried, and the acid regenerated by addition of acetic acid. Many attempts were made to crystallise this substance by addition of water, benzene, petroleum, &c., to its solutions in alcohol and ether, by fractional precipitation, and by purification through the lead salt, but to no purpose.Attention was therefore turned to the preparation of derivatives, in the hope that they might be more easily crystallised, and eventually a crystalline sodium salt was obtained by dissolving the acid in abso- lute alcohol, and adding to that solution alcohol in which metallic sodium had been dissolved, I n this way, a precipitate of the sodium salt was obtained in the form of microscopic needles. If, however, any attempt was made to remove and dry this salt, it absorbed water and formed a transparent jelly, even if the whole mixture was poured on a porous tile and the latter at once placed in a vacuous desiccator over calcium chloride. Experiments made with other salts were no more satisfactory, the potassium and ammonium salts being equally deliquescent, whilst salts of the other common metals are amorphous.Action of Acids on Aqueous LYoZutions of the Alkali Xalts of CaZZitroZic Acid.-When acids are added to aqueous solutions of the alkali salts of callitrolic acid, this acid is set free, forming a yellowish powder which may be either completely or partially insoluble in alcohol, depending on the concentrations of the acid used for the precipitation. Thus, if strong hydrochloric acid be used, the precipitate is almost insoluble in absolute alcohol, whilst if only a 10 per cent. solution of hydrochloric acid be added, a mixture of a soluble and an insoluble resin is obtained, and if acetic acid be used as the precipitating agent, the resin obtained is almost completely soluble.The insoluble resinEENRY: THE CONSTITUENTS OF THE SANDARAC RESINS. 1150 dissolves in alcoholic potash, and from this solution there can be regenerated by acetic acid a resin soluble in alcohol. The obvious explanation of this behaviour is, that callitrolic acid is a hydroxy- acid, which in the presence of mineral acids forms a Zactone. This lactone is insoluble in alcohol, acetone, ether, chloroform, benzene, or petroleum ; but dissolves in hot glacial acetic acid, from which it is deposited on cooling as a granular powder, which occasion- ally assumes a somewhat crystalline appearance, but has never been obtained in an undoubtedly crystalline condition. If the lactone be added to concentrated alcoholic solution of inactive pimaric acid, i t passes into solution, and, if the latter be diluted with alcohol, is reprecipitated as a white, granular powder.As no crystalline derivative of callitrolic acid, except the unsatis- factory sodium salt, could be obtained, i t was thought advisable to prepare specimens of the insoluble lactone in various ways, and submit these to analysis. These specimens of lactone were prepared : ( a ) by precipitation by concentrated hydrochloric acid from a specimen of freshly prepared crystalline sodium salt ; (b) by precipitation from alcoholic solution of pimaric acid, the precipitate being washed with absolute alcohol; (c) by precipitation from hot glacial acetic acid solutions. On combustion, the following results were obtained : (a) 0.2065 gave 0.5802 CO, and 0.1747 H20, (b) 0.2505 ,, 0.6969 CO, ,, 0.2140 H,O.C = 76.09 ; H = 9.50, 0.1600 ,, 0.4462 CO, ,, 0.1325 H,O. C = 76.06 ; H = 9.20. (c) Og283O ,, 0.7899 CO, ,, 0.2415 H,O. C = 76.14 ; H = 9.40. 0.1798 ,, 0.5080 CO, ,, 0.1490 H,O. C = 77.03 ; H = 9.18. C = 76.6 ; H = 9.3. C,,H,,O, requires C = 76.6 ; H = 9.7 per cent. The composition of callitrolic acid should therefore be represented by the formula C30H4805, which is confirmed by a large number of analyses of the silver salt prepared from the following specimens of the lactone through the intervention of the sodium and potassium salts : (i) From lactone deposited from alcoholic solutions of pimaric acid ; (ii) by solution of lactone, from acetic acid, in alcoholic potash, and precipitation with silver nitrate ; (iii) by solution of lactone, from acetic acid, in alcoholic potash and fractionation by addition of excess of aqueous potash, the fractions being converted into silver salt : (i) 0.2322 gave 0.0377 Ag.(ii) 0-5540 ,, 0.0981 Ag. Ag= 17.7. (iii) 0.1061 ,, 0*0200 Ag. Ag= 18.09. Ag= 18.02. 0.4132 ,, 0.0730 Ag. hg= 17-66. 0.1007 ,, 0.0180 Ag. Ag=17.80. C30H,70,Ag requires Ag = 18.14 per cent.1160 HENRY: THE CONSTITUENTS OF THE SANDARAC RESINS. Although, there€ore, the composition of callitrolic acid cannot at present be definitely asserted to be that represented by the formula c,,H,,O,, yet it is improbable that it is far removed from this. The acid and its lactone are not acted on by fused potash and hot fuming nitric acid.With the lat.ter reagent, the resin agglomerates into a semi-solid mass, and shows no sign of solution, even after warm- ing for several days on the water-bath. An aqueous solutionof the sodium salt slowly decolorises potassium permanganate, but the action soon stops unless the solution is kept hot. This is the only reaction, so far found, which seems likely to afford a method of attacking this sub- stance. When the acid or lactone is heated with hydriodic acid in Zeisel's apparatus, no methyl iodide is formed. The acid and its lactone both react with acetic and benzoic anhydrides, with the formation of insoluble acyl compounds, which have not yet been examined. Heating in a Vacuum.-When heated, callitrolic acid is completely decomposed, giving off carbon dioxide and an oily hydrocarbon, and leaving a hard, pitch-like residue.It was found that this operation gave a better yield of hydrocarbon when carried out under diminished pressure (360 mm.). The distillate consists of a viscous, oily liquid containing a little water, and having an odour of acetic acid. It was dissolved in ether, and the ethereal solution shaken out with dilute potash. The ethereal portion was separated, washed with water, dried over calcium chloride, and the solvent distilled of?. The residue was then distilled, almost the whole passing over from 230-285'. On analysis at this &age, the oil was found to contain less than 1 per cent. of oxygen, so that it was evidently a hydrocarbon. Its further purification was therefore conducted by distillation over metallic sodium.The final product, purified in this way, boiled from 270-280', was almost colourless when freshly prepared, but resinified slightly and became greenish on keeping, and had a faint odour of pepper- mint, especially when heated, I n appearance and odour it closely resembled the diterpene naturally occurring in the plant, and like it gave a purple coloration when concentrated sulphuric acid was added to its solution in acetic acid. Its density at 15'/15' was 0.9303. The hydrocarbon is optically active. Determinations of its specific rotation for sodium light, using a 100 mm. tube, gave as the mean of ten concordant determinations + 3 6 O , whence [ ajD + 38'42'. The refractive index was determined in a hollow prism of refracting angle 61O25' ; the minimum angle of deviation for sodium light was found to be 40"47', whence p = 1.5238.Combustions of this hydrocarbon, freshly distilled over metallic sodium, gave the following results :HENRY: THE CONSTITUENTS OF THE SANDARAC RESINS. 1161 resin ................. acid ..................... Diterpeiie occurring in Diterpene ex-callitrolic 0.1581 gave 0.510 CO, and 0.1615 H,O. c! = 87.9 ; H= 11.1. 0.2243 ?, 0,7269 CO, ), 0,2270 H,O. C=S8.3; H=11*2. C,,H3, requires C = 88-23 ; H = 11.77 per cent. The following tabular statement of the properties of the diterpene occurring in the plant and that obtained by destructive distillation of callitrolic acid shows clearly that they are identical : 260-280" 0.9386 CZoHB, 1.5215 270-280 0-9303 C,,H3, 13238 Specific Composi- Refractive 1 1 dens' 1 rotation.1 tion. 1 index. The difference in the optical rotation of the two substances is to be accounted for by the production of both dextro- and lsevo-forms during the destructive distillation of the callitrolic acid. Besin of Callit& Yerrucom. The resin of this plant has been examined in the way already described in detail in the foregoing part of this paper. I t contains pinene and a small quantity of a constituent of higher boiling point, of which sufficient could not be obtained for examination from the small amount of resin available. The resin itself is composed of in- active pimaric and callitrolic acids, the former being present in much larger quantity than in the case of the resin of Callitris quadrivcdvis. The softness of this resin is due to the greater proportion of pinene contained in it which, perhaps, also to some extent affects the rapidit,y of its solubility in alcohol.Volcbtile Resins. Although it is known that abietic acid is volatile when heated in a vacuum, this substance having been isolated by Kelbe from the distil- lation products of colophony (Ber., 1880, 13, StSS), and that d-pimaric acid can be distilled unchanged in a vacuum (Vesterberg, Zoc. cit.), yet this method has been but little used by investigators for the isolation of resin constituents, the only case of its application (which seems to have been accidental) being the preparation of cannabinol from the resin of Indian hemp by Messrs. Wood, Spivey, and Easterfield (Trans,, 1899, '75, 20).During the course of the present work it was found that distillation of sandarac under reduced pressure was a very con-1162 HENRY: THE CONSTITUENTS OF THE SANDARAC RESINS. venient way of obtaining inactive pimaric acid. The resin was broken into small pieces and placed in a Jena distilling flask having another similar flask attached to its side arm in the usual way, The flasks were then rendered vacuous (10-12 mm. pressure) and the resin heated by a Bunsen burner. At first a little water came over, and the resin melted and began to froth. The frothing was easily controlled by the use of a glass 1-piece, inserted between the pump and the flasks, having one arm closed by a piece of rubber tubing and a spring clip, so that the pressure in the flasks could be suddenly increased at will by opening the clip.After a time, the volatile oil began to distil over, the thermometer gradually rising to about 160'. The receiver was changed a t this stage, and a fraction up to about 240° collected. This was usually viscous when cold, and was found to be a mixture of pimaric acid and diterpene. The receiver was again changed and a fraction up to 300' collected, This was almost pure pimaric acid, and on redistillation usually gave a large fraction boiling a t 260° under 15 mm. pressure which, on solution in alcohol and addition of a little water, could be obtained in a crystalline condition (m. p. 171O). In this process, the callitrolic acid suffers decomposition, and so a large yield of diterpene is obtained in the earlier fractions.This can be purified by shaking the ethereal solution of the fraction with potash t o remove pimaric acid, and rectification as already described over metallic sodium. Among other resins which on distillation under diminished pressure give constituents of constant boiling point are mastic, myrrh, and Indian frankincense. The application of this process could no doubt be extended with great advantage to the investigation of this class of substances, about the chemistry of which so little is known owing to the difficulty of isolating well-defined products from them, Sicmmccry and Conclzcsions. Briefly stated, the principal results obtained in the course of the present investigation are as follows. It is shown that the crude resin consists of a mixture of resin acids and volatile hydrocarbons. The latter have been separated into a diterpene and d-pinene, Two acids have been isolated from sandarac resin.One of these has the composition represented by the formula C,,H,,O,. It is not iden- tical with abietic acid but is isomeric with Vesterberg's d-pimaric acid, and as it differs from the latter in being optically inactive, it is pro- posed to call it i-pmaric acid. The remaining acid of the resin is probably the chief constituent of Tschirch and Balzer's callitrolic acid, so that the latter name mayHENRY : THE CONSTITUENTS OF THE SANDARAC RESINS. 1163 conveniently be retained for it. It yields a lactone of the composition C30H4604, from which it may be inferred that the composition of the acid is represented by the formula C30H4805’ This lactone, although insoluble in all the usual solvents except boiling acetic acid, is dis- solved readily by alcoholic solutions of i-pimaric acid, and is reprecipi- tated from such solutions by the addition of alcohol, This phenomenon has already been observed by Johnston (Zoc.cd.), who found that a strong varnish of crude sandarac, made with alcohol, deposited the A resin on dilution with more alcohol. This experiment has been repeated, and the A resin of Johnston has been found to be identical with the lactone of callitrolic acid. The resin of Callitris verrucosa has also been examined and found to contain d-pinene, and the two resin acids already obtained from common sandarac. It should be pointed out that in many particulars the observations now recorded do not confirm those of Tschirch and Balzer. The sandaracolic acid of these authors was probably impure i-pimaric acid, and could not have given methyl iodide when heated with hydriodic acid, since no constituent of sandarac resin behaves in this way, as has also been shown by Gregor and Bamberger (Oesterr. Chsrn. Zed., 1898, 1, S), who obtained no methyl iodide when the crude resin was heated in Zeisel’s apparatus with hydriodic acid. The formation of acety 1 and benzoyl derivatives from sandaracolic acid (impure i-pimaric acid) is also inexplicable, except on the assumption that it contained much callitrolic acid, which is hardly probable if, as the authors say, their sandaracolic acid was distinctly crystalline. Tschirch and Balzer Eurther failed to observe the formation of the insoluble lactone when attempts are made to regenerate callitrolic acid from aqueous solutions of its alkali salts by addition of mineral acids. The formulze now proposed for the acid constituents of sandarac resin also differ con- siderably from those proposed by these authors. The experimental results obtained in the course of this work, although not yet sufficiently definite and extensive to enable a con- stitutional fomula to be assigned to i-pimnric acid, lend support to the view generally held that the resin acids of the Conifem are produced by the condensation and oxidation of terpenes ; a view to which con- crete expression has been given in the constitutional formulae assigned by Bruylants and by Bischoff and Nastvogel t o resin acids of the composition C20H300%, to which attention has already been drawn in the historical introduction to the present paper. This investigation has been carried out in the laboratories of the Scientific Department of the Imperial Institute, and I desire to express1164 O’SULLIVAN : GUM TRAGACANTH. my warmest thanks to Professor Dunstan both for the suggestion that I should undertake this work and for the valuable help he has given me during its pursuit. SCIENTIFIC DEPARTMENT, IMPERIAL INSTITUTE, S. W.

ISSN:0368-1645    

DOI:10.1039/CT9017901144

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

1164 O’SULLIVAN : GUM TRAGACANTH. CXXIV. -Gum Trugacanth. By CORNELIUS O’SULLIVAN, F.R.S. I. Introductovy. FOR a number of years, I have occupied myself, amongst other things, with a study of the constitution of gum tragacanth, but the investiga- tion is still not so complete as I should have wished it to be. Recently, however, Widtsoe and Tollens (Ber., 1900, 33, 132) described some of the products of the sulphuric acid hydrolysis of the gum, and this fact leaves me no alternative but to place on record the results I have hitherto obtained, and to indicate the direction in which I am still working. 11. Earlier Investigutions of the Composition of the Gum. Of the proximate composition of gum tragacanth, very little seems to be known, and where the character and composition of the proxi- mate constituents are described, it is difficult to resist the conclusion that our knowledge is of little value.We have to begin with the broad statement that gum tragacanth consists of cellulose, &arch, bassorin, a gum like arabin, a little nitro- genous matter, sugar, and ash. We are not told the nature of the cellulose; we have 110 evidence that the granules contained in the cells are starch granules, for although, without dobbt, they are coloured blue by iodine, we have no collateral proof in support of the assumption. Again, I have been unable to ascertain why the cellular matter apparent under the microscope is written down as cellulose. It cer- tainly gives a blue coloration with Schultz’s reagent, but I can find no further evidence.Bassovin is R very imperfectly defined substance, and it would indeed be difficult t o identify it from the general description given of it (Gmelin-Kraut, 1862, 4, 650).0 SULLIVAN : GUM TRAGACANTH. 1165 Of the 8olubh gunz, nothing further appears to be recorded than that it resembles arabin. The nitrogenous matter is simply indicated by the presence of nitrogen, and concerning the sugar there is noinforma- tion ; but the knowledge of the ash conetituents is of course satisfactory. 111. Object of t7he Work. With these facts in my mind, and looking upon gum tragacanth as of the nature of plant sap containing reseswe matter in an advanced stage of elaboration, it appeared to me-with the light thrown upon the constitution of the gums in general by my work on the gums of the arabin group-that some clearer idea of the constitution of this gum could easily be obtained, and thence of the more imme- diate materials of reserve matter. From the general description of bassorin, I was led to believe I should have to deal with some gum acid or acids related to those of the arabin or geddin series in a polymerised state; this, however, was found not to be the case; when the gum was treated with water, the solution was only slightly acid, the amount of potash required to render the mucilage neutral being very small, and the solubility thereof being practically unaltered.IV. Mode of Pvocedure. When the gum is treated with water, it swells up very considerably, and at least one hundred times its weight of water must be added before any differentiation occurs.The addition of alkalis does not materially alter this, consequently, the usual method of fractionating such materials was not available. When diluted as t,hus described, however, the so-called cellulose, with jelly-like matter and starch, begins to separate (Kutzing, Ph&sophimha Botanik, i, 203; H. von Mohl, Bot. Zeit., 1857, 32), and by this means a moderately clear solution, difficult to filter, is obtained. The cellulosic shreds occupy a large space in the liquid, but all attempts to get them to settle satis- factorily met with but indifferent success. Consequently, I deter- mined a t the outset to act on the gum with dilute sulphuric acid, to examine the products of the reaction, and then, if possible, to trace each product back to the original material whence it was derived.The investigation was accordingly carried out in this direction, and yielded interesting results, but as I believe I can describe the nature of the gum without utilising this series of experiments, I shall leave them unrecorded. I may, however, say that it was the knowledge derived from a study of the products of the action of dilute sulphuric acid on the gum-in which I was most materially assisted by Dr. Stern, my assistant at that time-and especially of the products other VOL. LXXIX. 4 K1166 O’SULLIVAN : GUM TRAGACANTH. than sugars, which enabled me to deal with the problem in the manner described in this paper. The results, so far as the sugars are con- cerned, will be found in the work of Widtsoe and Tollens (loc.cit.), although no indication is there given as t o the immediate source of these substances. I proceeded as follows : When water is added to the gum, the pieces swell up t o a more or less transparent jelly, some of them being very nearly transparent, others quite white and opaque, whilst every intermediate stage is also observed. Examined microscopically, the transparent jelly masses are found to consist of irregular, blown out ” cells, the thin walls being filled with glairy matter; the opaque pieces consist of the same kind of irregular cells, but containing, in addition to the glairy matter in the interior, many granules, apparently starch, which are coloured blue by iodine, whilst the intermediate varieties are distinguished by the varying numbers of granules they contain, this number apparently increasing with the opacity, V.The Granules. Although the granules are distinctive, and are coloured blue by iodine, T thought it desirable to isolate them, and t o determine abso- lutely their identity with starch. When the gum is submitted to the action of freshly prepared copper- ammonium solution, obtained by treating copper turnings with ammonia in the usual way, nothing is left undissolved but bright, almost transparent granules, which are deposited on the addition of a large bulk of water. On decanting off the copper solution and washing the residue with water, the aqueous filtrate was coloured brown by iodine solution, whilst on treatment with dilute hydrochloric acid, a solution was obtained which mas coloured dark purple by that reagent.On treating the remaining granules with iodine, a coloration not as intensely blue as that yielded by starch with the same reagent was observed. It was difficult to obtain the granules in sufficient quantity t o admit of a determination whether or no they yielded maltose on treatment with malt extract, but in order to procure some evidence on this point, about 150 grams of the gum were treated with 10 litres of water, after soaking, and allowed to stand for some days. The insoluble portion was then strained out, by means of a linen filter bag, washed with cold water so long as anything dissolved, and then pressed. Under the microscope, the mass was seen to consist of unaltered granules and shrivelled, cell-wall de‘bris. It was treated with boil- ing water, cooled down to 60-65’, and digested for several hoursO'SULLIVAK : GUM TRAGACBRTH.1167 with malt extract. A microscopical examination showed that the granules had been-dissolved, and on evaporating the filtered solu- tion to a syrup, and digesting this with alcohol of sp. gr. 0,830, a clear solution and an insoluble residue were obtained. The residue was neglected, but the solution, freed from alcohol by distillation and evaporated again to a thick syrup, mas taken up by alcohol of sp, gr. 0-820, in which it was completely soluble. After freeing this solution from alcohol, the residue was examined. The figures yielded by the aqueous solution were as follows: sp. gr. 1.029, ago* + 8.0'; whence [aID + 53.1'. This number approaches that of dextrose so closely as to leave little doubt that we have that substance present.From this observation, I do not, however, think it can be said that we have not starch to deal with, still I feel I am justified in recording the observation that these granules, apparently consisting of starch, yield on treatment with diastase, not maltose, but dextrose. There is still one more point t o which attention should be drawn here, namely, that the cell-walls are dissolved by copper-ammonium solution. Numerous attempts were made to isolate definite entities from this solution, but the results were not satisfactory; hence the use of that reagent in the investigation was discontinued. VI. 2% Cellulosic Xuktunce. Since the cell-walls described above did not appear identical in every respect with ordinary cellulose, an examination of the substance seemed desirable.Accordingly, a portion of the original gum was treated with three hundred times its weight of boiling water, digested for some time, and then submitted t o filtration through linen bags. The residue left in the bags was repeatedly treated with boiling water, and was finally collected on filter paper, a hot water funnel being employed. The filtered shreds which comprise the whole of the cellular matter are completely soluble in freshly prepared copper-ammonium solution, in which only the granules remained insoluble when the whole gum was treated with the reagent. Examined microscopically, the cellular mass was found to consist of shreds and d%bris, a portion of which gave a blue colour with zinc chloride solution of iodine, the remainder being coloured reddish-brown; in fact, i t was quite obvious that the shreddy mass, although showing in its parts no material differences under the microscope, consist of two or more distinct substances.Besides the cellular shreds, a few hard, well-defined crystals, which are neither sulphate nor carbonate of calcium, are also present, but as they occur in extremely small quantity, I have not examined them further. * The number gives the length of the tube in which the observation was made, in mm. 4 ~ 21168 O'SULLIVAN : GUM TRAGACANTH. The amount of cellular matter present in the gum varied betwsen 1 and 3 per cent. A portion of it wae repeatedly extracted with boil- 'ing water, dehydrated with strong alcohol, and dried, h s t in a vacuum and then in a current of dry air at 100' On combustion : 0.322 gave 0.498 CO,, 0.175 H20, and 0.030 ash.C=46*51 ; H=6.65 per cent. (in substance free from ash). Ash = 10.3 per cent. These results appear to indicate that the cell-walls do not consist of cellulose proper, however closely they may resemble the oxycelluloses. The ash contained silica, lime, phosphoric acid, ferric oxide, &c. Action of Xulphuric Acid on t h Cellular Substance.-Some of the cellular matter, purified as described above, was washed, first with a dilute solution of potasb, then with dilute hydrochloric acid, and finally with water, till free from chlorine. The jelly thus obtained consisted of shreds, and was digested at 98-99' with a 5 per cent.solution of sulphuric acid for an hour. During the digestion, a marked odour of furfuraldehyde was observed. At the end of the time stated, the solution was filtered, and the insoluble portion washed with boiling water till free from sulphuric acid. The filtrate was neutralised with baryta water, the precipitated barium sulphate filtered off, and the filtrate concentrated in a vacuum to a syrup; this was then taken up with alcohol of sp. gr. 0.820, in which it was almost entirely soluble. After removal of the alcohol by distillation, the syrup which remained behind yielded, on standing, a crop of microscopic, skiff-shaped crystals of arabinose, such as this sugar yields at times on crystallisation from slighty impure solutions. The crystals wepe washed with dry methyl alcohol, and dried in a current of dry air at 100'.1.820 grams, dissolved in water and made up to 100 c.c., gave ago + 3-5', whence [a], + 96.2'. This figure is low for arabinose, but no lower than I have obtained before under similar conditions. The airdried crystals lost no weight at 100'. On recrystallising the preparation from water, crystals with the characteristic terminations of arabinose, as yielded by arabic acid, were obtained. These were washed with methyl alcohol and dried, first in air, and then at 100'. 1.054 grams, dissolved-in water and made up to 100 c.c., gave UY + 2-15', whence [aJD + 102*0°. As the low opticity of the sugar at the outset might have been due t o the presence of galactose, a portion of the original syrup was treatedO'SULLIVAN : GUM TRAGACANTH.1169 with nitric acid of the proper strengh, but no mucic acid was produced ; dextrose it might have been, but sufficient material was not at my disposal to determine the point. I consider, however, that most prob- ably the disturbing cause is the Eubstance of low rotatory power which is always prc;duced when arabinose is subjected to the action of sulphuric acid for any length of time. It is evident, therefore, that the cellular matter, on treatment with sulphuric acid as described, yields practically nothing but arabinose. The residue from this treatment, insolubIe in sulphuric acid, is a jelly-like mass which, under the microscope, appears to consist of a number of shreds with no definite structure, in fact it differs very little in appearance from the original cellular matter, Iodine solution colours some of.the shreds blue, others brown, whilst the remainder are unchanged. More of the shreds are coloured blue by zinc chloride solution of iodine than by iodine alone, but some are still only coloured brown; a solution of iddine and sulphuric acid also acts in much the same way, except that a larger proportion of the shreds appear to be coloured blue in this case. A few acicular crystals are still observable. It is clear from these experiments, therefore, that even after digestion with 5 per cent. sulphuric acid, the residue is not homogeneous, never- theless a portion of it was dried in a current of dry air a t looo, and subjected to combustion, to enable me to form an idea of the change, if any, which had taken place.C = 45.75 ; H = 6.52 per'cent. (in substance free from ash). Ash = 6 -15 Hence there is a clear indication o€ a diminution of carbon and hydro- gen, which cannot be explained by the elimination of an arabinose group alone ; the time at my disposal, however, did not permit of my going more deeply into the question. It may be pointed out, however, that the sugar solution contained a considerable quantity of uncrystal- Zisable matter, a careful examination of which would, very possibly, throw some light on the point. With the object, however, of ascer- taining whether or not the above cellulose-like substance contained a fixed cellulose residue, it was repeatedly treated with bromine water and then with ammonia.Under this treatment, it soon became evident that the substance was dissolving gradually, and after about one-third of the original substance had disappeared, the residue was collected, thorouglg washed with boiling water, dehydrated with strong alcohol, and finally dried in a current of dry air at looo. On combustion of a portion of it, 0.336 gave 0.531 GO,, 0.186 H,O, and 0.0195 ash. per cent.1170 O’SULLIVAN : GUM TRAGACANTH. 0.284 gave 0.457 CO,, 0.1595 H,O, and 0.008 ash. C=45*15 ; H=6*42 per cent. (in substance free from ash). Ash= 2.8’1 per cent. Here, again, we have a diminution in the carbon and hydrogen, and ako, as might be expected, in the ash, with.a gradual approach, so far as the carbon and hydrogen are concerned, t o the normal composition of cellulose, but since the substance gradually went into solution under the influence of bromine and ammonia, the absence of an unalterable residue of normal cellulose was conclusively proved.Hence it is perfectly clear that the cell walls, seen under the microscope, although they yield many of the reactions of normal cellulose, have so far no ascertainable relationship to it, Whether the substance or substances are converted in the ordinary process of anabolism into true cellulose or not, it is impossible to say, and the series of changes by which such a transformation could be effected is not easy to imagine. I can only repeat that the cellular matter of gum tragacanth yields many of the reactions of true cellulose and arabinose on treatment with sulphuric acid, but leaves no permanent residue when acted on with bromine and ammonia.VII. The Portion of Gum Tragacanth soluble in Water. Sample I. On evaporating the aqueous filtrate from the cellulosic shreds, a gelatinous scum forms on the surface of the liquid, and on cooling the solution, after some concentration, a considerable quantity of jelly-like matter falls out ; in fact, the solution becomes a jelly if the concentra- tion is carried far enough. An attempt at fractionation was made by skimming off the scum and pressing out the jelly, but no satisfactory results were obtained ; hence the solution was concentrated to about one-sixth of its original bulk, and alcohol added gradually in small portions at a time till a ‘‘ break ” was effected, when further addition of alcohol produced a bulky, curdy precipitate, ‘‘ fraction a.” This could be readily separated from the clear, alcoholic mother liquor, which we shall call “fraction p.” VIII.Fraction p. The alcohol was distilled off, and the aqueous solution concentrated in a vacuum to a syrup. On carefully adding alcohol of sp. gr. 0.840 t o this syrup, a flocculent precipitate ‘‘ fraction 7’’ was thrown out, which was allowed t o settle, and on decanting off the clear, supernatant solution and adding more alcohol, a waxy precipitate, similar in appearance to that yielded by gerlda gum, was thrown out. An examination of fraction p was first made.O'SULLIVAN : GUM TRAGACANTH. 1171 This precipitate was dissolved in a little water, roprecipitated by alcohol of sp. gr. 0*830 in presence of hydrochloric acid, and handled in precisely the same way as described by me in connection with the gedda gums (Trans., 1891, 59, 1032). It was divided into three portions, fractions I, 11, 111, fraction I being the least soluble.These fractions were freed from hydrochloric acid by repeated pre- cipitation with alcohol, dehydrated with strong alcohol, and finally dried in a current of dry air at 100' under 250 mm. pressure. The optical activity of each fraction was then determined with the follow- ing results : Fraction I. [.ID - 78*0°. ,, IT. [alD -58.8 . ,, 111. [aID -88.1 . From these it is evident that we have not a homogeneous body to deal with, although the product is not such a mixture as was the case with the gedda gum acids. A barium salt of fraction I1 was prepared by neutralising a solution of i t at the boiling temperature with clear baryta water, using neutral Iitmus as indicator.The solution of the barium salt thus prepared mas concentrated, precipitated by alcohol, and dehydrated by alcohol of sp. gr. 0.820. On analysis, 0.783 gram of this salt, dried in a current of dry air at loo', gave 0.037 gram of barium sulphate, BaO =3*23 per cent. This figure indicates a molecular weight corresponding t o that of a fraction of the gum acids of gedda gum C (Trans., 1891, 59, 1073); the rotations, too, of the fractions from the two sources are nearly equal in amount, although opposite in sign. Hence the soluble gum acids of gum tragacanth resemble those of gedda gum, but are lsvorotatory instead of dextrotatory. VIIIA.Action of SuZphuric Acid on Fraction /3 p r i j e d . Fractions I1 and I11 of the soluble gum acids mentioned above were mixed, dissolved in water to a 30 per cent. solution, and this was heated in the water-bath to loo', sufficient diluted sulphuric acid being added to make the mixture contain 3 per cent, of that acid. The digestion was continued for 15 minutes, and, after cooling, the acid was neutralised with clear baryta water. The whole was then con- centrated in a vacuum to a syrup, because the barium sulphate could not be satisfactorily removed by filtration. This syrup was pre- cipitated by excess of alcohol of sp. gr. 0.820, and the clear alcoholic solution containing the sugar or sugars was freed from alcohol by distillation, concentrated in a vacuum to a syrup, which was then1172 O’SULLIVAN : GUM TRAGACANTH.taken up by as little dry methyl alcohol as possible; a small amount of barium salt remained insoluble. The clear methyl alcoholic solution, -on standing, yielded stellate groups of crystals, with the terminations and general characteristics of arabinose. These were collected, washed with methyl alcohol, and their optical activity determined. It was found to be [aID +90*8O. As, however, this number was far too low for arabinose, the crystals were redissolved in methyl alcohol, a little insoluble matter filtered off, and the solution again allowed t o crystallise. Three crops of crystals were collected, namelJr, a, 6 , and c, and the optical activity of each was determined, with the following results : a [a], + 102O.6 [a], +104. c [aj, + l o 6 . These numbers clearly agree with those accepted for arabinose, and although the crystals have not absolutely the same form as that assumed by arabinose obtained from arabic acid, there can be no doubt about their identity with that substance. The amount of arabinose, including the uncrystallisable matter in the mother liquors, yielded by the gum acid varied between 73-0 and 76.7 per cent. of the dry material taken. When the percentage of arabinose thrown out in arriving at this stage is considered, the high molecular weight attributed t o the original soluble gum acid is amply confirmed. The precipitate thrown down by alcohol, from which the sugar solu- tion was separated by decantation, was treated with a little water, and sufficient sulphuric acid added to convert nearly all the barium present into sulphate. Alcohol was then added until the solution ‘‘ broke.” In this way, the barium sulphate easily falls out and can be separated, whilst the partially degraded gum acid is retained in the dilute alcoholic solution.This can be precipitated by the addition of strong alcohol, and may be easily freed from excess of sulphuric acid by redissolving in water and reprecipitating with alcohol several times. After freeing from sulphuric acid, the degraded gum acids were divided into two fractions by means of alcohol. Each fraction was converted into a powder by means of strong alcohol, Barium salts were also made by neutralising a portion of each with clear baryta water, and precipi- tating the concentrated solutions with strong alcohol, and these were dried in the usual way.An examination of the free acid and barium salt of each fraction was made, with the following results : salt thereof BaO = 10 per cent, Free acid. Most soluble portion gave +335O, and the bariumO'SULLIVAN : GUM TRAGACANTH. 1173 Free acid. Least soluble portion gave [.ID + 33*2', and the barium salt thereof BaO = 8.8 per cent. I n each of theso instances, the substance was dried in a current of dry air a t 100'. If these factors are compared with those obtained for tri- and di- galactangeddic acids (Trans., 1891, 59, 156-157), an almost exact agreement is observed, hence these degraded gum acids are a mixture of the tri- and di-galactangeddic acids.I n further confirmation of the galactan nature of these degraded gum acids, a determination was made of the amount of muciq acid formed from them by treatment with nitric acid in the usual way. Seventy to eighty per cent. of mucic acid was thus obtained, and this result confirms the identity of these degraded acids with those of the geddic series. As was naturally to be expected, on further treating these acids with sulphuric acid, galactose and a further degraded acid, corresponding to, if not exactly identical with, geddic acid were obtained. I n order to determine whether or not other samples of gum tragacanth would yield like results, a fresh sample of the gum from a different source was examined. IX. Portion ofthe Gum soZubEe in Water. Sarnph 11. A. Examination of Praction corresponding to p- Fraction. On treating the second sample of gum tragacanth in precisely the same way as described for the first, a product was obtained correspond- ing to /?-fraction, which yielded fractions with opticities [a], - 9 6 O to [a], - 115' ; these gave barium salts which contained from 4 to 5.4 per cent.BaO, the evidence, curiously enough, being that the neutral- ising power for barium increases with rising rotatory power. When these results are compared with those obtained for the similar acids yielded by sample I, it becomes evidebt that we are dealing with members of the same series. Sample I. Free acid [a]D - 88'; barium salt 3-23 per cent. BaO. )) I r e ?? [.ID - 9 6 ; ,, 44 1, , I 9 9 11* 19 [a]D -115; ,? 5.4 99 99 It is clear, therefore, that although the gum acids belong t o the same series, the number of arabinose yielding groups is less in the more optically active acids than in those producing a smaller rotation.IXB. Action of Xulphwic Acid on P-Fraction. SampZe 11. We have now to decide whether or not this is the only difEerence between the gum acids. To determine it, fractions of opticity between1174 O'SULLIVAN : GUM TRAGACANTH. [ a ] , - 95" and [ a ] = - loo", neutralising about 4 per cent. barium, were mixed and digested with 3 per cent, sulphuric acid for 30 minutes. The products were separated as usual, and 72.5 per cent. of sugar of [ a l D +looo was obtained, This was recrystallised from methyl alcohol, and several crops were separated which possessed the charac- teristic terminations of arabinose and yielded the following factors : [ a ] , +101-104".K 101-105, These figures conclusively prove that the sugar is arabinose. Much non-crystallisable matter possessing a low opticity was present in this as in-the first case, but whether this is produced by the action of sul- phuric acid on arabinose, or represents a sugar which, like dextrose, crystallises with difficulty in presence of contaminating matter, I am unable to say. Amongst some of the products of the react.ion, galactose is present without doubt, for on treating this uncrystallisable matter with nitric acid, mncic acid is produced, X. The Degvaded Gum Acids-from Sample 11. Using the method of purification and fractionation already men- tioned, products were obtained having opticities varying between [ .ID + 34' and [ a 3, + 40.6", and yielding neutral barium salts con- taining 10-11.8 per cent.of BaO. These figures agree almost abso- lutely with those obtained when the first sample of the gum employed was subjected to similar treatment, notwithstanding the fact that the original acids acted on by sulphuric acid varied considerably in optical activity. I may here indicate that these degraded acids are necessarily mix- tures, the more highly dextrorotatory portions being those from which a portion of the constituent yielding galactose has been removed, whilst those of lower opticity have either lost less of this constituent, or only part or the whole of that yielding arabinose. XI. Purlher Bydrolysis of the Degraded Acids. The fractions having [ aID + 34" to + 4 0 * 6 O just mentioned were mixed, dissolved in water to a 30 per cent.solution, and digested at about 98' for 2 hours with 4 per cent. sulphuric acid. Clear baryta water was added t o neutralise the cooled liquid, and then alcohol of sp. gr. 0.850 so long as a precipitate was formed. This consisted of the bariumLsalt of the degraded acids, some sugar, and barium sulphate. The clear alcoholic solution containing the greater part of the sugar or sugars was decanted off, and the precipitate further freed from sugar by digesting with alcohol of sp. gr. 0.870, redissolving in a littleO'SULLIVAN : GUM TRAGACANTH. 1175 water without separating the barium sulphate, and reprecipitating several times with alcohol of the strength mentioned.The alcoholic solutions thus obtained were mixed, the alcohol dis- tilled off, and the residual solution concentrated in a vacuum to a syrup. On examination, the solid matter in this was found to have an optical activity [ aID + 60--65O, and to contain barium salts of gum acids. Consequently the whole of the syrup was digested f o r some time with alcohol of sp. gr. 0.520 in a flask with a reflux con- denser. Much gummy matter remained insoluble, and, on cooling, more was precipitated, leaving the alcoholic solution clear. When this solution was again freed from alcohol and concentrated in a vacuum, a syrup was obtained which crystallised on standing. After a few recrystallieations, the substance had a crystalline form similar to that exhibited by galactose under certain conditions.[ aID + 80-83O. On examination, the crystals yielded the following results ; K = 93-95', and on treating them with nitric acid under the most favourable conditions, 72-75 per cent. of mucic acid was obtained, Hence the sugar is undoubtedly galactose. Returning now to the barium salt, partially freed from the sugar as just described. It was treated with the least possible quantity of water, and an attempt unsuccessfully made to separate the barium sulphate by filtration; it was not possible to obtain a clear filtrate, consequently sulphuric acid was carefully added until the barium present was completely precipitated, and then alcohol until a '' break " was effected, when the barium sulphate with a little gum acid separated out, leaving the alcoholic solution clear.This was decanted off; it contained the greater part of the degraded gum acid. Treatment with alcohol of sp. gr. 0.820 enabled me to separate this into two fractions. a, a less soluble one, and b, one more soluble; these were dried in the usual way and the optical activity of each determined : a gave [aID +93*So. 6 ,, [aID +94*1°. A barium salt of each was prepared, that of: a yielded BaO= 18.1 per cent. b ?t 17-6 I, In another series of experiments in which the acids with opticities between [ a]D + 34" and 40° were acted upon with 4 per cent. sulphuric acid for 4 hours, degraded acids were obtained in precisely the same way as described, of which the optical activity was somewhat higher, namely, [aID + 109.7-109*5', but the barium salts of these yielded practically the same numbers, namely, BaO= 18.6-1 8.03 per cent.1176 O'SULLIVAN : GUM TRAGACANTH.To enable me to form some notion of the composition of these sub- stances, one of the apparently purest barium salts, dried in dry air at 100' under 275 mm. pressure, was burned with the fcllowing results : C=34*41; 0.474 gave 0-573 CO,, 0-184 H20, and 0.113 BaCO,. C2,H,,0,1,Ba0 requires C = 34.45 ; H = 4.49 ; BaO = 19.10 per cent, I have attributed (Trans., 1891, 59, 1054) the formula C23H38022 to geddic acid of [ a ] D + 71' and C2,H,,02,Ba0 to its barium salt. The latter formula requires C = 33-70 ; H = 4.64 ; BaO = 18.58 per cent. On comparing these results, we observe a broad agreement between them, but one not sufficiently close as to enable us to state that the degraded acids from both sources are identical, although it can hardly be doubted that there is a close relationship.The composition of the two acids is no doubt the same, namely, C23H38022, but geddic acid has uD + 71', whilst the acid under consideration has aD + looo to logo, and the barium salts are different, as is shown by the analyses. I n dealing with non-crystallisable substances of this kind, and taking cognisance of the fact that they are exceedingly difficult to dry, I do not wish to draw more inferences than the analytical numbers warrant. But, I may say these have not been based on one set of experiments, but on many. Hence, I feel justified in concluding that the degraded acid of tragacanth, if not absolutely identical with geddic acid, very closely resembles it, and, on comparing the products obtained from both the original undegraded acids after being acted upon by sul- phuric acid for 10 to 15 minutes, I feel convinced that the partially degraded acids obtained in each case are very closely related, if not identical.They both have the game optical activity, and their barium salts yield the same amount of baryta, as has been shown above. It is sufficiently clear that the primary acids of gum tragacanth are not identical with those obtained from gedda gum, although they have many properties in common, the chief differences being that the former acids are laevorotatory, whilst the latter are dextrorotatory, and, unlike the gedda gum acids, do not yield ayabinon as a pro- duct of their partial hydrolysis with sulphuric acid.Possibly, this occurrence of arabinon-y ielding acids may have something to do with the differences in the direction of the rotation, especially as the products after the elimination of the arabinon groups agree so closely in optical properties and neutralising power. It is thus evident that the- acid8 of gum tragacanth, soluble in dilute alcohol are polyarabinon-trigalactan-geddic acids, namely, XC oHlsO,, 30, 2H20010,C23H38022, with the differences indicated above and by this formula. H = 4.32 ; BaO= 18.51.O’SULLIVAN : GUM TRAGACANTH. 1177 One of the fractions of the soluble gum acid under consideration, namely, that with [all) - 8 8 O and containing 3-23 per cent. BaO in the barium salt, is probably represented by the formula : 1 1 oH,cO,, 3Ci 2H2 00,o ,c, 3H31302,~ BaO.This requires 3.29 per cent. BaO, and should yield on partial hydro- lysis 71.7 per cent. of arabinose. It has been shown above that between 72 and 76 per cent. of moderately pure arabinose was obtained from the mixed gum acids. From these facts, it appears clear to me that the constitution of the soluble gum acid of gum tragacanth has, broadly, been sufficiently well established and indicated. The Nitrogenous Matter. Of this, I cannot a t present say more than that it is less soluble in alcohol than the gum acids just described, in fact, it is fraction y, mentioned on page 1170 ; that, when once precipitated and dried, it does not again give a clear solution in water, whilst it is soluble, with a slight brown colour, in potash, and that it does not give the proteid reactions given by the nitrogenous substance from gedda gum (Trans., 1891,5Q, 1061).XII. Fraction a. Flit? Jelly-like Portion. I ‘ Bassorin.)) It has been pointed out in the earlier portion of this paper that the clear filtrate, obtained in the process of removing the cellulose-like shreds from the product of the digestion of gum tragacanth with a large bulk of water, yielded on evaporation a gelatinous scum and a jelly-like deposit, and that the solution, when brought to this state of concentration, yields the bulky precipitate with dilute alcohol which was mentioned when the elimination of the soluble gum acids, fraction p, was described, This precipitate was repeatedly washed with dilute alcohol, dissolved in the least possible quantity of water, acidified with hydrochloric acid, and placed upon a dialyser to free it from salts of calcium, magnesium, &c.When the solution on the dialyser was free from hydrochloric acid, dilute alcohol of sp. gr. 0.870 was added to i t ; a white, curdy precipitate was thrown out, which, on decanting off the supernatant liquid and adding stronger alcohol, became shred-like. This was well washed with alcohol of sp. gr. 0.850, and then de- hydrated by alcohol of sp. gr. 0.S25, when it could readily be rubbed down to a powder. It is undoubtedly the substance known as 6ussorin.1178 O'SULLIVAN : GUM TRAGACANTH. This preparation, dried until constant in a current of dry air at loo', gave [ + 98O. I do not give the analytical numbers, because up to this point I have no criterion of the purity of the substance.It may, however, be here pointed out that the opticity of the gum acids soluble in alcohol of sp. gr. 0.870 is almost identical with the above number, although opposite in sign. A barium salt of the preparation was made by neutralising an aqueous solution thereof with clear baryta water. While doing this, it was noticed that at the point where the baryta water dropped into the solution, and, consequently, where the reagent was in excess, a lemon-yellow colour was developed. By cautious addition of the reagent, however, a neutral solution was obtained without the pro- duction of much colour, and this, on addition of alcohol, yielded a curdy precipitate, which, after being mashed with dilute alcohol and dried in a current of dry air at looo, coutained BaO = 9.2 per cent.XIIA. Conversion of Bassorin into a- and P-Tragacanthan-xyZan- bcmsoric Acids. When an attempt was made to dissolve the above barium salt for the estimation of the barium, a portion was found to be insoluble; hence, it seemed as if some change had taken place, presumably under the influence of the alkali employed. Numerous attempts were made to purify the original bassorin by partial precipitation with alcohol, but with no great success, conse- quently the whole preparation was converted into a barium salt by treatment with baryta water. After this salt had been dried in a vacuum over sulphuric acid, and finally in a current of dry air at looo, it was observed that a part was insoluble in water, as already mentioned.The insoluble portion admitted of being easily filtered off. The filtrate was submitted to dialysis in presence of hydro- chloric acid until free from barium. To tbe solution, alcohol was added, and the precipitate, after redissolving and reprecipitating with alcohol several times until all the hydrochloric acid had been removed, was strained out, pressed, dehydrated, dried in a vacuum over sul- phuric acid, and finally in a current of dry air at 100'. 0.971 gram, dissolved in water and made up to 50 c.c., gave a solu- tion of sp. gr. 1.0063 and an opticity a:' +2'5', whence [a], + 128'. D = 4.27. It will be noticed that the [a], is much higher than that of the original substance, and the divisor much greater than that of any known carbohydrate.Further, it is obvious that we have in no way to deal with the original material.O'SULLIVAN : GUN TRAGACANTH. 1179 On attempting to prepare a barium salt of this substance by neutralising its aqueous solution with clear baryta water, the addition being made drop by drop, a gelatinous precipitate was immediately thrown out. This precipitate, formed in as neutral a solution as pos- sible, was collected and mashed, first with water, then with dilute alcohol, and finally dehydrated and dried as usual. 0.448 gave BaSO,=0*116. BaO= 17.0 per cent., a result which confirms the conclusions arrived a t from the [a],, and D. As has been mentioned previously, the neutralisation of the original solution of bassorin with clear baryta water gave rise t o no pre- cipitate of any kind, whereas the neutralised solution yielded on pre- cipitation with alcohol a substance which, after drying, was not again entirely soluble in water.The portion, of the neutralised precipitate insoluble in water was also insoluble in hydrochloric acid, but mas soluble in potash or ammonia. From these facts, it is evident that the substance known as bassorin is not a stable compound, but undergoes some change under the influ- ence of the alkali employed in the preparation of one of its salts. What the nature of this change is, I do not propose to discuss a t present ; it is sufficient to say that when an excess of milk of lime or baryta water is added to a strong solution of bassorin in water, a dense, curdy, light lemon-yellow precipitate is thrown down, which can be collected, washed with alcohol, dehydrated, and dried at 100' without developing a more intense coloration.On treating the dry mass with an excess of dilute hydrochloric acid, much carbon dioxide is evolved, and a large, semi-curdy portion remains insoluble ; this can be easily filtered off, the filtrate being perfectly clear. The insoluble portion admitted of being washed with cold water, and dehydrated and dried as usual by treatment with strong alcohol. This may be called fi*action B. Addition of alcohol to the clear acid filtrate yielded a curdy precipi- tate calledfractiofi A . On analysis : We shall deal with the latter first. Frccction A . The white, curdy precipitate was washed free from hydrochloric acid by dilute alc~hol, and was pressed and,dried.A small portion of this substance was found to be insoluble in water. This was collected, and alcohol added to the filtrate so long as a precipitate was produced. On drying as usual, this yielded the following results on analysis : 0.83 gram, dissolved in water and made up to 50 c.c., gave a solution of sp. gr. 1.00696 and a:' +4.5', whence [aID + 135. D=4.19.1180 O'SULLIVAN : GUM TRAGACANTH, It will be observed that this opticity is still higher than that of the substance with which I started. Is the substance even now homo- geneous ? To ascertain this, an aqueous solution of the acid was treated with sufficient clear lime water to precipitate about half the solid matter present. A bulky precipitate of calcium salt was thrown out, which was easily filtered, and could be readily washed with water and dilute alcohol ; this was pressed and dried as before.We call this portion fruction A,. To the filtrate, hydrochloric acid in excess was added, and then alcohol so long as a precipitate was formed. This mas collected on a filter, washed with dilute alcohol until free from chlorine, and then dried. Both fractions were redissolved in water containing hydrochloric acid, then reprecipitated with alcohol, and washed free from the acid. They were again redissolved and reprecipitated several times, and analyses of each made, with the following results. Fraction A,.-1.288 grams (dried in dry air at 100' under 300 mm. pressure), dissolved in water and made up to 50 c.c., gave a solution of sp.gr. 1.01062 and u'g0 + 7-14', whence [:.ID + 138.6" and D 4.12. Fraction A,.-1.700 grams, dissolved in water and made up to 50 c.c . gave a solution of sp. gr. 1.01404 and u y + 9*4', whence [a]= + 138.2' and D 4-13. These results justified me in considering that I had a pure substance Combustions of fractions A, and A,, dried in ,dry air at looo and Fraction A,.-o*341 gave 0.537 CO,, 0.169 H,O, and 0.003 ash. Fraction A,.-0.338 gave 0.530 CO,, 0.166 H,O, and 0.004 ash. We call it fraction A,. t o deal with, and accordingly I mas able to proceed to its analysis. 300 mm. pressure, were made, with the following results : C = 43.43 ; H = 5.56 ; ash = 0.80 per cent. C = 43.41 ; H = 5.52 ; ash = 1.20 per cent. The ash in both cases was mainly calcium carbonate.and D, namely, that the substance is homogeneous. which requires : These numbers confirm the conclusions arrived at from the opfiicities The empirical formula calculated from these numbers is C24H36021, C = 43.63 ; H = 5.46 per cent. Barium 8ak-A portion of the acid used in the foregoing analysis was dissolved in water, neutralised at the boiling point with ammonia, neutral litmus paper being used as indicator, and barium chloride solu- tion added so long as a precipitate was formed. The precipitate SOO’SULLIVAN : GUM TRAGACANTH. 1181 obtained was collected and washed with cold water until free from chlorine,* The barium salt so prepared can be easily dried in the usual may, and rubbed down to a fine powder. On analysis : 0.388, dried in dry air at looo, gave BaCO, 0.096.BaO= 19.21. C,,H,,O,,,BaO requires BaO = 19 94 per cent. Determinations as BaSO, yielded the same results. behaves in like manner, but its solubility in water is slightly greater. Calcium XaZt.-This salt is prepared similarly to the above, and 0.326, dried in dry air at looo, gave CaCO, 0.048. CaO= 8-24, C,,H,,020,Ca0 requires CaO = 8.02 per cent. Further details concerning these products need not now be given, as I propose to treat the subject more fully in a future paper. h U u e r SuZt.-An attempt was made to prepare the silver salt of the acid, but the task was beset with many difficulties. About 0.5 gram of the acid was dissolved in water, neutralised with ammonia, and the solution made up to about 45 C.C. On adding ordinary silver nitrate solution to this, the whole was converted into a transparent jelly of sufficient density to admit of the beaker being inverted without dis- turbing its contents.One hundred c . ~ . of water were added, and the mixture well stirred and thrown upon a filter, the operation being conducted in a room lighted by ruby light. Much of the liquid passed through, but it was difficult to free the precipitate entirely from its mother liquor. This end, however, was t o some extent achieved by pressing the gelatinous mass between folds of filter paper, but on attempting to wash the fairly dry substance with water, i t again swelled up, and the above process of filtration and drying had to be repeated. On drying in a vacuum over sulphuric acid in the dark, the salt became brown, and when an attempt was made to dry it in a current of dry air at looo, it blackened completely.Under these circumstances, i t seemed hardly worth while to estimate the silver in the preparation, but in the hope that an analysis might lend some support to the conclusions indicated by the previous experi- ments, a portion of the salt, dried in a vacuum over sulphuric acid (not, however, until constant, owing to slow decomposition of the salt) was nnslysed, with the following results : 0,372 gave 0.11 AgC1. Ag=22*2. C,,H,,O,,,Ag,O requires Ag = 24-77 per cent. * The barium salt is sufficiently soluble in cold wntcr t o give a precipitate with silver nitrate, that is, the silver salt of the acid is less soluble than the barium salt, consequently the absence of chlorine must be proved by silver nitrate iu presence of nitric acid.VOL. LXXIX. 4 1,1182 O’SULLIVAN : GUM TRAGACANTR. This result is, considering the circumstances, sufficiently close to support the conclusions based on previous experiments. To the gum acid giving rise to these salts, the name a-tragacanthccn- xyZan-bassoric acid may be given, for reasons which may simply be indicated here. Hydrolysis of a-Tragacanthan-xylan-basswic Acid. When a 20 per cent. solution of the acid is digested for 20 minutes at the temperature of a boiling water-bath with a 5 per cent, solution of sulphuric acid, a sugar is obtained on the one hand which proves to be a pentose having the opticity [a], - 30’ or thereabouts. This is a new sugar which I propose to name “t~agacanthose ” (it may be I-xylose, but I have not sufficient of the substance to enable me to decide the point at present); on the other, a new acid is produced the barium salt of which was found on analysis to contain 22.5 per cent.BaO. ClgH2,01,Ba0 requires BaO = 23.07 per cent., and the acid from this salt on combustion gave numbers corresponding with those required by the formula C19H2801p The action of sulphuric acid upon a-tragacanthan-xylan-bassoric acid-[ a ] D + 135O-is represented by the following equation : C24H36021 + H2° = C5H1005 + C19H2f401? Tragmanthosc Xylan-bassoric acid. - or 1-xylose. The opticity of the new gum acid in neutral solution (potassium salt) was found to be [ a ] , + ZOOo or thereabouts. This acid is only slightly soluble in cold water, and its barium and calcium salts are almost insoluble.On acting upon xykm-bassoric acid still further with 5 per cent. sulphuric acid in the same way as on the original substanee, another sugar, xylose, was eliminated and another new acid, namely, bassoric acid, was produced. The action of sulphuric acid is represented by the following equation : C19H28017 + H2° = c,H1oo, + cl*H,oo,, X ylose. Bassoric acid. The sugar produced was proved to be xylose by its crystalline form, K, optical activity [ + 21’ (it has a high temporary activity), and by the depression of the freezing point of its solutions. Bassoric acid is only very slightly soluble in cold water, it gela- tinises on treatment with boiling water and separates from this jelly, on cooling, in much the same way as inulin does from its solutions.The optical activity of the acid in alkaline solutions was [ a ] D + 255”, and the neutral barium salt contained BaO=28 to 29 per cent.O'SULLI VAN : GUM TRAGACANTH. 1183 Cl,H,801,Ba0 requires BaO=28*S per cent. This salt is almost insoluble in water. I shall not describe this final acid further on this occasion, but I may point out that the composition seems to indicate a combination of two hexans with C,O,. I have suflicient acid to determine this point and other things con- nected therewith definitely, and the work is in hand. Fraction B. The crumb-like substance, left insoluble in hydrochloric acid when the dried precipitate obtained with milk of lime was treated with that reagent (p. 1179)) was washed free from hydrochloric acid with cold water, rubbed down to a powder with alcohol of sp.gr. 0.820, dried in a vacuum over sulphuric acid, and then in dry air a t 100". 0,972 gram so dried, dissolved in the least possible quantity of potash, and the solution made up to 50 c.c., gave aim +6.0", whence Barium XaZt.-A portion of the acid was converted into barium salt by precipitating the neutral potassium salt solution with barium chloride, filtering off the precipitate, mashing free from chlorine, and drying it with alcohol, then in a vacuum over sulphuric acid, and finally in dry air at 100'. 0.378 gram of the salt thus dried was treated with excess of dilute hydrochloric acid in the cold for 24 hours, and the insoluble residue filtered off and washed free from hydrochloric acid.The barium in the filtrate was precipitated in the usual way as sulphate. It amounted to 0-107 gram BaSO,, hence BaO = 18.6 per cent. The percentage of BaO agrees sufficiently closely with that yielded by the barium salt of fraction A, to indicate that we have a substance of the same composition to deal with, but there is no evidence, so far, that the material is homogeneous. I converted the whole of the portion of [a], + 154O into barium salt. It may be pointed out that unless the solution of the ammonium or potassium salt is not moderately concentrated, the barium salt is not thrown out in an easily filterable condition on the addition of the barium chloride. The barium from the salt was extracted with hydrochloric acid as already described, and the free insoluble acid was divided into bwo fractions by dissolving i t in the least possible quantity of ammonia and partially precipitating the solution with barium chloride.The first precipitate, which may be called B,, after continued stirring was [ u ] D + 154'.1184 O'SULLIVAN : GUM TRAGACANTH. filtered off, and a second, B,, precipitate was obtained from the filtrate by adding more barium chloride solution, Both fractions were dried and freed from barium by treatment with hydrochloric acid as described already. Fraction B,, 0.766 gram (dried in a vacuum over sulphuric acid and in dry air at loo'), dissolved in the least possible quantity of dilute potasb, and the solution made up to 50 C.C. gave 2:O +5.0°, whence [.ID + 163.2'. Fraction B,. The fraction from the second precipitate with barium chloride mas treated and examined in the same way. 0.684 gram in 50 c.c dilute potash solution, gave +4*5', whence [.ID + 1645'. These numbers are in sufficient agreement to warrant the conclusion that the substance dealt with is practically homogeneous. On com- bustion of a portion of each of the fractions, the following results were obtained. Fraction B,. 0.3525 gave 0.5565 CO,, 0.1795 H,O, and 0.0020 ash. Fraction B,. 0.3715 gave 0.5580 CO,, 0.1870 H,O, and 0.0005 ash. BP B,. C.. . . . 43-30 per cent. H.... 5-68 ,, 1 5.59 7, } free from ash. Asb.. 0.57 ,, 0.17 ,, 43.24 per cent. Calculated on substance These numbers agree sufficiently well among themselves, and if they be compared with those obtained for a-tragacanthan-xylan-bassoiic acid, the agreement is so close as to warrant the conclusion that the two acids are isomeric. 1 shall call this acid P-t~~gacant~ccn-~~~a?a- bassoric mid. This conclusion was confirmed by an examination of the products of the sulphuric acid, hydrolysis of the /I-acid, the laevorotatory sugar, xylan, the intermediate acid [ aID + 200' (barium salt of which contains 22.46 per cent, BaO), and the final acid with [a]= + 255'and a barium salt containing 28.8 per cent. BaO being obtained, So far, these two acids are described with sufficient distinctiveness to enable anyone t o recognise either of them, and in this position I leave them for the present. I hope in the immediate future to describe bassorin itself more accurately, to indicate the reactions by which it is connected with a- and P-tragancanthan-xylan-bassoric acids, and to describe more closely the laevorotatory pentose, which is the first product of their hydrolysisCONDENSATION OF PHENOLS WITH ESTERS. 1185 by sulphuric acid. There can be no doubt that xylose is the second sugar eliminated. Of this, however, I may have something further t o record later on. Both xylan-bassoric and bassoric acids were eliminated from the products of the action of sulphuric acid on theundifferentiatedgum, biitit was difficult to prepare pure substances, as mixtures of tragacanthan- xylan-bassoric acids with these acids existed amongst the products. I: have to thank my assistants, Dr. A. L. Stern and Mr. J. A Walker, M.A. (Oxon.), for the helpful assistance they have given me in carrying out the work of which, I in justice must say, this paper is only a brief summary, but which I hope to amplify in the immediate future, more especially in dealing with the cellulosic residue, the nitro- genous constituent, and bassorin.

ISSN:0368-1645    

DOI:10.1039/CT9017901164

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

CONDENSATION OF PHENOLS WITH ESTERS. 1185 CXXV.-Conderzsation of Phenols with Esters of the Acetylene Swies. Part VI. By SIEGFRIED RUHEMANN and ERNEST WRAGG, B.A. PREVIOUS researches led to the result that ethyl acetylenedicarb- oxylate and ethyl chlorofumarate yield the same esters on treatment with the sodium phenolates, and that the acids formed from them on hydrolysis readily condense to derivatives of 1 : 4-benzopyrone under the influence of concentrated sulphuric acid. As has also been shown, the acids obtained from the products of the interaction of the sodium phenolates with ethyl phenylpropiolate cannot be thus transformed into flavone and its homologues, but on distillation lose carbon dioxide, yielding phenoxystyrene and its homologues, and on treatment with sulphuric acid decompose into carbon dioxide, acetophenoue, and the corresponding phenols.Similar is the behaviour of the substances produced from eugenol and m-xylenol, which is described in this paper. Although we have not been able to obtain the benzopyrone compound from eugenoxyfumaric acid, yet xylenoxyfumaric acid can readily be condensed to dimethyl- benzopyronecarboxylic acid. P-m-Xylenoxycinnamic acid, on the other hand, is completely decomposed by sulphuric acid. The fact that the aryl ethers of P-hydroxycinnamic acid are not transformed into benzopyrone derivatives induced us to ascertain whether this reaction is prevented from taking place only by the pre- sence of the phenyl group, or whether hydrocarbon radicles in general VOL. LXXIX. 4 M1186 RUHEMANN AND WRAGG : CONDENSATION OF PHENOLS have this effect.For this purpose, we have studied ethyl /3-phenoxy- crotonate, which is formed by the action of sodium phenolate on ethyl P-chlorocrotonate, and have found that the corresponding acid does not yield a benzopyrone compound, but undergoes changes similar to those observed in the case of the aryl ethers of P-hydroxycinnamic acid. On heating, it loses carbon dioxide and forms P-phenoxypropylene, thus : CH3*C(O*C6Hg):CH*C02H = CO, + CH,*C(O*C,H,):CH,, whilst under the influence of sulphuric acid it suffers the following decomposition : CH,~C(O*C,H,):CH*CO,H + H,O = CO, + CH3*CO*CH3 + C,H5*OH. With the view of testing whether the difference in the behaviour of the aryl ethers of /3-hydroxycinnamic and P-hydroxycrotonic acids from that of the ethers of hydroxyfumaric acid is caused by the con- figuration of the unsaturated acids, we have subjected /3-chloroiso- crotonic acid, instead of its stereoisomeride, to the action of sodium phenolate.We find, however, that the same compound is formed as when ethyl P-chlorocrotonate is used. This result may be explained by the assumption that the formation of ethyl P-phenoxycrotonate is preceded by the addition of sodium phenolate t o the chlorocrotonic esters, accompanied by the transformation of ethyl /3-chlorocrotonate into ethyl /3-isochlorocrotonate. The resulting substance would thus - . CH,=E*O*C H ', which on account of the CO,Et*C*H have the configuration 6 axial position of phenoxyl to the ester group could not yield a benzo- pyrone compound. EX PER^ MENTAL.The union of eugenol with ethyl chlorofumarate takes place when the unsaturated ester (1 mol,) is gradually added to a solution of sodium (1 at.) in an excess of the phenol. The dark, viscous product is heated for a short time, and, after standing for several hours, treated as in the former cases. The ester is a yellowish oil which boils at 231-232' under 14 mm. pressure ; it possesses an aromatic odour, and at 2l'/Zl' has the density 1-1 256. 0.2030 gave 0.4822 CO, and 0-124'7 H,O. On analysis : C = 64.73 ; H= 6.82. C,,H,,O, requires C = 64.67 ; H = 6-58 per cent. il I31 [41 Eugenosyficmaric Acid, C3H,(O*CH3)CGH3.0* C( C0,H): CH*CO,H. - The potassium salt of the acid separates as a crystalline solid on boil-WITH ESTERS OF THE ACETYLENE SERIES. PART VI.1187 ing the ester with alcoholic potash for 2--3 hours. After the product has been freed from alcohol by distillation on the water-bath, water is added to the residue, and the solution treated with an excess of dilute sulphuric acid, when the organic acid separates as an oil. This is prevented from solidifying on account of the presence of eugenol, which is formed along with eugenoxyfumaric acid on hydrolysis of the ester. In order t o remove the phenol, the ethereal solution of the oil is shaken with sodium carbonate, and an excess of dilute sulphuric acid added to the aqueous layer. The organic acid which separates is best extracted with ether, and, after complete evaporation of the latter, remains as a yellow solid, which is very soluble in ether or alcohol. It readily dissolves in boiling water, and, on cooling, crys- tallises in yellowish plates which melt and decompose a t 172-173', On analysis : 0.2142 gave 0.4755 CO, and 0.0980 H,O.C1,H,,OG requires C = 60.43 ; H = 5.03 per cent. Eugenoxyfumaric acid dissolves in concentrated sulphuric acid, forming a dark red solution. After standing overnight, it is gradually poured into cold water, when a brownish, gelatinous precipitate is produced, which we have been unable to obtain in a crystalline form, and therefore have not further examined. C = 60.54 ; I3 = 5-08. Action of the Xodium Derivative of m-Xy%nol on Ethyl Phen&ropiolale. Ethgt p-m-Xylenoxpcinnumate, The action of ethyl phenylpropiolate (1 ~nol.) on a hot solution of sodium (1 at.) in an excess of m-xylenol takes place very readily.The sodium derivative of the phenol, which parlly separates on adding the unsaturated ester, disappears. The dark red oil which is formed sets, on cooling, t o a resin. After standing for some hours, it is agitated with dilute sulphuric acid and ether ; the ethereal layer is then freed from the excess of the phenol by potash, the ether evaporated, and the remaining oil distilled in a vacuum. It boils a t 225-226' under 10 mm. pressure, is colourless, and at 2lo/2l0 has the density 1.0946. On analysis: 0.187'7 gave 0*5300 CO, and 0.1180 H,O. C = 77.0 ; H = 6.98. C11,H200, requires C = 77-02 ; H = 6.76 per cent. P-m-Xylenoxycinnamic Acid, (CH3)2C6H3*O*C(C6H5):CH=C02H.- The ester is hydrolysed when it is boiled with alcoholic potash for 2 hours. On adding dilute sulphuric acid to the alkaIine fluid after evaporation of the alcohol on the water-bath, @m-xylenoxycinnamic [1:3] 141 4 M 21188 RWHEMANN AND WRAGG : CONDEKSATION OF PHENOLS acid is precipitated a s a resin, which, on stirring with a little alcohol, sets to a solid.This dissolves in hot dilute alcohol, and the solution, on cooling, yields an emulsion from which colourless prisms gradually separate. On analysis : The acid melts a t 121-122O with evolution of gas. 0*2000 gave 0.5575 C0,and 0*1080 H,O. C = 76.02 ; H= 6.0. C,?H,GO, reqriires C = 76.12 ; H = 5.97 per cent. The siher salt is obtained as a white precipitate on mixing the solution of the acid in ammonia with silver nitrate; i t is neither changed on exposure to light nor decomposed on drying at 100'.On analysis : 0.2994 left, on ignition, 0.0858 Ag. Ag = 28.66. C,?H,,O, Ag requires Ag = 28-80 per cent. [1:3] [JI P-m-Xylenoxystyrene, (CH,),C,H,*O*C(C,H,) :CH2.-/3-m-Xylenoxy- cinnamic acid, on heating, loses carbon dioxide, and P-m-xylenoxy- styrene is formed, It is a colourless oil with a n aromatic odour, distils at 178' under 15 mm, pressure, and a t 3l0/2lo has the density 1.0353. On analysis ; 0.1700 gave 0.5343 CO, and 0.1090 H,O. C = 85-71 ; H = 7-12, C,GH,,O requires C = S5.71; H = 7.14 per cent. Action of the #odium Derivative of m-A7yZenol on Ethyl Chlorofumnrate. CH,/\CH, ~H.CO,*C,H,. Ethyl m-Xylernoxyfumarate, \/-O-C I 1 CO,-C,H, This compound is formed in a similar manner t o the other aryl ethers of ethyl hydroxyfumarate, that is, by graduaily adding ethyl chlorofumarate (1 mol.) to a hot solution of sodium (1 at.) in a n excess of m-xylenol.The dark product, after treatment as in the former cases, yields a yellowish oil which boils at 202-203° under 17 mm. pressure, and at 2lo/2lo has the density 1.0978. On analysis : 0.2033 gave 0,4892 CO, and 0,1263 H20. C = 65.62 ; H = 6-92. C,6H200, requires C = 65.75 ; H = 6.85 per cent. "i] r 4 m-Xylenomjfumaric Acid, (0 H ,)2C,H,-O*C( CO,H):CH* C0,H.-The ester is readily hydrolysed by boiling it with alcoholic potash. After thealkaline solution has been freed from alcohol by distillation on the water-bath, water is added t o the residue, and then an excess of dilute sulphuric acid. The solid, which is precipitated, dissolves in boiling water with diaculty, but with great ease in alcohol or ether,WITH ESTERS OF THE ACETYLENE SEHIES. PART VI.1189 and crystallises from dilute alcohol in yellowish prisms which melt and decompose at 2 1 0 O . On analysis : 0.2025 gave 0.4539 CO, and 0.0955 H,O. W = 61.13 ; H = 5.24. C,,H,,05 requires C = 61.01 ; H = 5.08 per cent. 6 8-Dimethyl-l ; 4-benxo~~rone-2-ccr,rbowylic Acid, ma-Xylenoxyfumaric acid dissolves in cold concentrated sulphuric acid, forming a red solution. After standing overnight, this is gradually poured into cold water, when a white, gelatinous precipitate is formed, which crystallises from dilute alcohol in colourless prisms. These melt and decompose at 27S0, and are freely soluble in alcohol but insoluble in water, On analysis : 0.2028 gave 0.4916 C02 and 0.0860 H,O. C = 61.11 ; H = 4 7 1 .C1,HloO4 requires C = 66.05 ; H = 4.59 per cent. CH3 0 \/' CO/CH 6 : 8-DimetlM~Z-1 : 4-benxopys.one) /\/ 'RH.--On heating the dimethylbenzopyronecarboxylic acid, it loses carbon dioxide, and a yellowish oil distils over which rapidly solidifies. The solid is freed from a small quantity of the acid which it contains by shaking the ethereal solution of the distillate with sodium carbonate. On evapora- tion of the ether, the dimethylpyrone remains behind ; it crystallises from dilute alcohol in colourless needles which melt a t 80-81" and dissolve in concentrated sulphuric acid, forming a colourless solution with a bluish fluorescence. On analysis : CH) 1 0.1974 gave 0,5482 CO, and 0.1047 H,O.C = 75.73 ; H = 5.89. Cl,H1,O, requires C = 75-80 ; H = 5.75 per cent. Action of Xoclium Phenolate on the Esters of P-Chlorocrotonic and p - Chloroisowotonic A cids. Ethyl P-Phenox ycrotonccte, CH3 C (0 C,H,) : CH CO,* C,H,. -Sodium phenolate reacts with ethyl P-chlorocrotonate as readily as with ethyl chlorofumarate on adding the ester (1 mol.) to a hot solution of sodium (1 at.) in an excess of phenol. The dark oily product, when sub- jected t o the same treatment as in the former cases, yields a colour- less oil with a pleasant aromatic odour, which distils at 147-148"1100 CONDENSATION OF PHENOLS WITH ESTERS. under 14 mm. pressure, and a t 21"/21" has the density 1.0726. analysis : On 0.1980 gave 0.5065 CO, and 0.1236 H,O. C12HI,0, requires C = 69.90 ; H The ester, on hydrolysis with alcoholic potash, is transformed into P-phenoxycrotonic acid, CH,*C(O*C,H,):CH*~O,H.On adding dilute sulphuric acid to the alkaline solution, after evaporation of the alcohol, the acid is precipitated as a white solid which dissolves in ether or alcohol with great ease, but only sparingly in water, and crystallises from dilute alcohol in colourless needles melting at 155". On analysis : C = 69-76 ; H = 6.93. 6.80 per cent. 0.2105 gave 0.4971 CO, and 0.1062 H20. C1,HloO3 requires C! = 67.41 ; I3 = 5.68 per cent. The silver salt is formed as a white precipitate, which is first gelx- tinous, but gradually becomes curdy, on adding silver nitrate to the solution of the acid in ammonia. The salt is insoluble in water, and has to be dried in a vacuum, since it turns brown when heated at ZOO".On analysis: C = 67-28 ; H = 5%5. 0.2805 left, on ignition, 0.1065 Ag. Ag= 37-96. CI,H,O,Ag requires Ag = 37.89 per cent, P-Phenoxycrotonic acid, as has bean mentioned (p. 1 l86), when dis- solved in concentrated sulphuric acid, or when boiled with dilute sul- phuric acid, suffers a decomposition similar to that of the aryl ethers ol /3-hy droxycinnamic acid, and furnishes carbon dioxide, phenol, and ace tone. P-Phenoxy~roz~~Zene, CH,* C( O*C,H,): CH, .--On heating P-phenoxy- crotonic acid in a vacuum, i t distils with partial decomposition ; this, however, is complete on distillation under the atmospheric pressure. The colourless oil so obtained, boils a t 170°, and has an odour resem- bling that of phenyl mustard oil. On analysis : 0.2400 gave 0.7118 GO, and 0.16 LO H,O. C,HloO requires C = 80.60 ; H = 7.46 per cent. As stated on p. 1186, ethyl /3-chloroisocrotonate yields the same pro- duct as ethyl 6-chlorocrotonate, when it is treated with sodium phenol- ate. The substance obtained from the former ester distils at 152" under 18 mm. pressure, as compared with 147-148' (under 14 mm. pressure) which we have found for the sample prepared from ethyl chloro- crotonate. Its composition, nioreover, has been verified by the fol- lowing analysis : C = 80.88 ; H = 7.45, 0.1938 gave 0.4960 CO, and 0.1178 H,O. C= 69.80 ; H = 6.75. C,,HI,O, requires C = 69.90 ; H = 6.80 per cent.THE IIY DROBROMIDES OF UNDECYLENIC ACID. 1191 The identity of both specimens of ethyl P-phenoxycrotonate is also supported by the fact that the acids formed from them on hydrolysis have the same crystalline forms and melting points, GONVILLE AND CAIUS COLLEGE, CAMBRIPGE.

ISSN:0368-1645    

DOI:10.1039/CT9017901185

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

THE IIY DROBROMIDES OF UNDECYLENIC ACID. 1191 CXXVI.-Y%c fIycld)~-omicles of Undecylenic Acid. By JAMES WALKER and JOHN s. LUMSDEN. BRUNNER (Bey-., 1886, 18, 2226), by the addition of hydrogen bromide to undecylenic acid, CI,H,,02, obtained a bromundecylic acid, C,,H,,O,Br, which fused at 35’. No details of the mode of preparation or purification are given. The same acid is mentioned by Nordlinger (Ber., 1890, 23, 2357), but again no details are given. Nardlinger also, by the addition of hydrogen bromide to the methyl and ethyl esters of undecylenic acid, prepared the corresponding esters of a bromundecylic acid, As it has been proved with practical certainty that ufidecylenic acid has the formula CH,:CH*[CH,],*CO,H, compounds obtained from it by the addition of hydrogen bromide must have one or other of the formula : CH,Br*CH,*[CH,],*CO,H and CH,*C€€Br*[CH,~,*CO2H. Nordlinger, on the strength of the rule that the halogen atom in such additions generally takes up the position more remote from the carboxyl group, assumes that Brunner’s acid has the formula CH,Br*[CH,]9*C0,H and that the esters which he himself prepared are the esters of this acid.Since these esters have been made the starting point for determining the constitution of various substances, i t is plainly of importance to know if Nordlinger’s assumptions are justified, CH,Br*[CH,],*CO,H is not Brunner’s acid, which has in all probability the other con- stitution, C?H,*CHBr*[CH,],*CO,H. Both these acids are simul- taneously formed by the addition of hydrogen bromide to undecylenic acid, and no doubt the esters of both are produced by the addition of hydrogen bromide to undecylenic esters, a circumstance which would explain the divergent results obtained by different observers in syntheses involving their use.In the present paper, it is shown that the acid1192 WALKER AND LUMSDEN: Addition of Hydrogen Bromide to Undecplenic Acid. The hydrogen bromide which we used in the following experiments was in all cases free from bromine, and dried by means of phosphoric oxide. Addition without the use of a Solvent.-The following is a typical experiment. Seven grams of undecylenic acid were saturated with hydrogen bromide at the ordinary temperature. The acid fused and became slightly warm. Absorption ceased when 35 grams of the gas had been taken up.Dry air was then led through the liquid product to remove the excess of hydrogen bromide. This occasioned a loss of 0.5 gram, so that 7 grams of undecylenic acid had united with 3.0 grams of hydrogen bromide, the calculated quantity being 3.1 grams. After remaining for some time in a vacuous desiccator, the liquid partially solidified, and the crystals (4 grams) were separated from the oil (6 grams) by filtration. The crude crystals were spread on porous tiles to remove the oil which still adhered to them, and were recrystallised from warm light petroleum. The substance separated in clusters of needles which melted a t 50°. The oil did not solidify at the laboratory temperature even after long-continued standing, but crystallised on cooling to Oo.The crys- tals were washed on the ice-cooled filter with cooled light petroleum, and were then spread on porous tiles. On recrystallisation from light petroleum, they melted at 359 In this experiment, Brunner's acid mas formed in about equal propor- tion with another acid of higher melting point, The proportions of the two acids vary very much in different experiments-, sometimes one, sometimes the other, preponderating. Addition in Ethereal Xolut iom-Seven grams of undecylenic acid were dissolved in anhydrous ether, and the solution saturated at the ordinary temperature with hydrogen bromide, the excess of which was after- wards removed by a current of dry air. On evaporation of the ether, the residue solidified, and was purified by spreading on a porous tile and recrystallisation from light petroleum.Five grams of Brunner's acid melting at 35' were thus obtained. Tbe presence of the ether seems to favour the formation of the isomeride of lower melting point. Addition in, Toluene Solution.-Twenty-five grams of undecylenic acid were dissolved in 20 grams of toluene, the solution cooled in ice, and saturated with hydrogen bromide. When saturation was com- plete, a solid separated, which was filtered off, thoroughly mixed with a little light pstroleum at Oo, and refiltered. After drying on a tile, its weight was found to be 16 grams and its melting point 49-50°.THE HYDROBROMIDFX OF UNDECYLENIC ACID. 1193 The filtrates on cooling to Oo deposited a further amount of solid, which was purified as already mentioned.I n all, 26.5 grams of the acid of higher melting point were obtained from the 25 grams of undecglenic acid, and this we have found to be the best method of preparing it. w-Bromundecylic Acid, CH,Br*[CH,],*C02H, This acid, prepared in toluene solution in the manner just detailed, is insoluble in water, but freely soluble in the ordinary organic sol- vents, for example, alcohol, ether, chloroform, or benzene. Whilst easily soluble in warm light petroleum, it is only sparingly SO at the ordinary temperature, and very sparingly so a t 0". Light petroleum therefore forms the most convenient solvent for its recrystallisation. I t usually separates in clusters of fine needles, which, when pure, melt sharply a t 51' without discoloration or evolution of gas. The sub- stance gave the following numbers on analysis : 0.1472, heated in a Carius tube with 0.4323 AgNO,, required 1 9 9 C.C. of decinormnl NH,CNS to precipitate the excess of AgNO, Br = 30.05.C,,H,,O,Br requires Br = 30.19 per cent. The substance may be warmed either by itself or in organic solvents to a temperature considerably above its melting point without noteworthy evolution of hydrogen bromide occurring. The aqueous solutions of its alkali salts also are compsratively stable, showing little tendency to the separation of bromide and regeneration of undecylenic acid. o-Hydroxyundecylic Acid, CH2(0H)*[CH,],*C0,H. Thirteen grams of o-bromundecylic acid were dissolved in the calcu- lated quantity of normal sodium hydroxide solution, and the resulting liquid was warmed for 12 hours a t 60-70' with excess of freshly precipi- tated silver hydroxide, the mixture being constantly agitated by means of a Witt stirrer.The action was then complete, bromine in m y form being absent from the solution, The silver compounds were removed by filtration, treated with a little warm dilute sodium hydroxide solution, and again filtered. The filtrates mere united, and acidified with nitric acid, whereupon a solid acid separated, which was filtered off, washed with water, dried on porous tiles, and crystallised from benzene. On recrystallisation from much hot water, the acid separated in clusters of very long, fine needles, and melted a t 70". From the above quantity of bromundecylic acid, 5.5 grams of the purified hydroxy-acid were obtained.0.0801 gave 0*0800 H,O and 0.1922 CO,. 0.1206 of the calcium salt gave 0.0372 CaSO,. C = 65.43 ; H = 11.10. C,,H,,O, requires C = 65.35 ; H = 10.S9 per cent. Ca= 9.07. (C,1H,0,)2Ca requires Ca = 9*05 per cent.1194 WALKER AND LUMSDEN: The acid is thus monobasic, and has the composition of a hydroxy- undecylic acid. I t is easily soluble in alcohol or ether, moderately so in benzene, separating readily from a warm solution, and sparingly in light petroleum. One hundred parts of water at 20" dissolve 0.04 part of the acid. As it is more than 20 times as soluble in boiling water, it can easily be purified by crystallisstion frdm this solvent. A solution of the sodium salt containing 1 part in 200 is freely precipitated on addition of soluble salts of barium, caloium, strontium, silver, zinc, or mercury.The barium, strontium, calcium, and silver salts are much more soluble a t the boiling point than st the ordinary temperature. The calcium salt was purified for analysis by recrys- tallisation frorn boiling water. The solution of sodium salt of tho above strength affords only a slight precipitate with a soluble mag- nesium salt. A more concentrated solution of the sodium salt, however, gave a curdy, somewhat stringy, precipitate, which dissolved slightly on heating, and was reprecipitated in a granular form on cooling the filtered solution, As this hydroxyundecylic acid is derived from the straight-ohain undecylenic acid, it also has its carbon atoms in a straight-chain. On oxidation with chromium trioxide, it is converted into a dicarboxylic acid having the same number of carbon atoms as itself.The hydroxyl which it contains is therefore part of a primary alcohol group. The acid therefore must have the constitution CII,(OH)I[~H~]!,*CO~H, and consequently the bromo-acid from which i t was derived must be CH,Br*[CH,],*CO,H. n-Nonanedicnrboxylic Acid, CO,H*[CH,],=CO,H, One gram of o-hydroxyundecylic acid was dissolved in glacial acetic acid, and to the solution were added 10 c,c. of a 1 : 10 solution of chromium trioxide in glacial acetic acid, A slight rise of temperature was observed when the solutions were mixed. The mixture was allowed to remain overnight, and on the following morning was gently warmed to complete the oxidation. The solution was then poured into cold water, when a white precipitate separated.This was filtered off, washed with water, dried on porous tiles, and recrystallised first from benzene and then from boiling water, In this way, 0.6 gram of an acid melting at 110' was obtained, Analysis yielded the following results. 0.1323 gave 0,2968 CO, and 0.1112 H,O. 0.1545 required 28.5 C.C. of N/20 NaOH for neutralisation. C=61*17; H=9.34. C,,H,,O, requires C = 61 -11 ; H = 9.26. Re- placeable H = 0-922 j calculated for C,HI,(CO,H), replaceable H = 0.926,THE HYDROBltOMIDES OF UNDECYLBNIC ACID. 11115 The substance is thus a nonanedicarboxylic acid, and its derivatiob from undecylenic acid shows i t to have the normal structure. rt-Nonanedicarboxylic acid resembles sebacic acid, and the - other higher members of the series of normal saturated dibasic acids in ap- pearance and properties.It is soluble in alcohol or ether, can be crys- tallised readily from warm benzene, and is very sparingly soluble in light petroleum. One hundred parts of water a t 20' dissolve 0,014 part of the acid. It is much more soluble in boiling water, from which i t separates on cooling in lustrous scales, indistinguishable in appearance from those obtained under similar conditions from n-decanedicarb- oxylic acid and n-brassylic acid. The melting point of the purified substance is l l O o , and falIs into place in the series of melting points of the group of normal acids to which it belongs, thus : Acid (evcii). iilelting point. Acid (odd). Succinic .................. Ad il'i c .....................Sitberic .................. Scbacic .................. Decanedicarboxylic.. .... Dadecaneclicarboxylic . , 181" 119 141 133 127 123 98" 103 107 110 113 Gliitaric:. I'iuiclic. Azelaic. Noiinnetlicarboxylic. 15 mssylic. A solution Of the sodium salt containing 0.6 grstu in 100 C.C. was precipitated in the cold by solutions of calcium, zinc, silver, or mercuric salts. Barium salts gave no immediate precipitate in the cold, but a granular precipitate formed on heating the solution t o the boiling point. Magnesium salts gave no precipitate in either hot o r cold solution. A solution containing 3 grams of the sodium salt in 100 C.C. gave a slight precipitate with magnesium nitrate in the cold, which greatly increased in bulk on heating tho solution to looo. The calcium salt is very nearly equally soluble in hot and in cold water.Byomundecylic Acid, m. p. 35". This acid, originally prepared by Brunner, is by no means so stable as the o-bromundecylic acid melting a t 51'. It melts sharply a t 35", hut the fusion is usually accompanied by the formation of minute bubbles of gas, no doubt hydrogen bromide. Traces of hydrogen bromide are lost on warming the liquid, either by itself or in solution. Analysis of a specimen recrystallised from warm light petroleum gave 29.9 per cent. of bromine instead of 30.2 per cent. required by the formula CllH2,0,Br. The acid is freely soluble in the ordinary organic solvents, but insoluble in water. It is considerably more soluble in light petroleum than the isomeric w-bromundecylic acid, and can easily be crystallised from this solvent, the crystals assuming the form of thin plates or1186 THE HYDROBROMIDES OF UNDECYLENIC ACID, oblique prisms.I n contact with an alkaline solution, i t readily loses the elements of hydrogen bromide with simultaneous formation of undecylenic acid. Thus an attempt was made to convert it into the corresponding hydroxy-acid by treatment of its sodium salt with silver hydroxide. The action was conducted at the ordinary temperature, and took a fortnight for completion, the product being then worked up as detailed under w-hydroxyundecylic acid. The resulting acid was liquid, and only partially solidified on long standing. It was found to be unsaturated, and analysis showed it to consist of impure undecylenic acid. This tendency of the bromo-acid to revert to undecylenic acid made direct proof of its constitution difficult to procure.The tendency to lose hydrogen bromide would of itself, however, indicate that the bromine is not primary. Moreover, we know the primary bromo-acid, and since the mode of formation from undecylenic acid admits of only two possible constitutions, and the possibility of stereoisomerism is excluded, it is practically certain that the bromundecylic acid melting at 35’ has the constitution CH,*CHBr*[CH,],*CO,H, in opposition to Nordlinger’s assumption. Xyndlmis of n-Brassylic Acid. Both Komppa (Bey., 1901, 34, 897) and Krafft and Seldis (Ber., 1900, 33, 3571), starting from the ester obtained by the addition of hydrogen bromide to ethy€ undecylenate, have by means of a malonic ester synthesis prepared undecanedicarboxylic acids, which both originally held to be the normal acid, for both postulated that the bromundecylic ester with which they worked was the w-derivative.The acids which they obtained, however, differed entirely from each other; that of ICrafft and Seldis melted at 113-114’, being iden- tical with ordinary brassylic acid, whilst Komppa’s acid melted a t 8 2 O and gave entirely different derivatives. In order to ascertain definitely which was the normal acid, we per- formed the synthesis with an ester prepared from pure w-bromunde- cylic acid. I n converting this acid into its ethyl ester, it is necessary to employ more alcohol than usual, for although it dissolves readily enough in pure alcohol, it is thrown out of solution when sul- phuric or hydrochloric acid is added.Five grams of the acid were heated with 150 C.C. of atlcohol and 5 C.C. of sulphuric acid on the water-bath for 6 hours. This yielded 4.5 grams of the ethyl ester, boiling at 188-190’ under 18 mm. pressure. On performing a malonic ester synthesis with this amount in the usual way, the liquid became neutral after 20 hours’ heating. The mixed esters were extracted and dried, and saponiEed by addingWALKER AND LVMSDEN : N-DECANEDICARBOXYLIC ACfD. 1107 them while hot to a boiling solution of alcoholic potash. A white precipitate of potassium salt separated in a few minutes. From this the tribasic acid was liberated by hydrochloric acid, and appeared as a pure white, bulky, flocculent precipitate which melted when the water was warmed, and solidified on cooling.The dry substance melted in bulk a t about 60°, and in a melting point tube a t 70°, with evolution of carbon dioxide, which became very brisk above 100'. After all the carbon dioxide had been driven off, the residual dibasic acid was recrystallised from boiling water. It formed pearly scales melting at 11 1-1 12'. On recrystallisation from warm benzene, i t melted a t 112-113°, and agreed in its other properties with the brassylic acid derived from erucic acid, which has therefore undoubtedly the normal structure. No doubt the esters employed by Krafft and Seldis on the one hand, and Komppa on the other, although appbrently prepared in the same way, contained different proportions of the two possible bromunde- cylic esters (compare p. 1191), so that in the one case the normal undecanedicarboxylic acid resulted from a malonic ester synthesis, and in the other case an isomeric acid. Fileti and Ponzio (abstract in Bey., 1893, 26, Ref. S11, from J. pr. Chem., [ ii], 48, 323) give the solubility of brassylic acid in 100 parts of water at 24' as 0.74. This is obviously erroneous, as even acids so low in the series as suberic and sebacic acids do not attain even approximately this degree of solubility. An experiment with our synthetic brassylic acid gave a solubility of 0.004 in 100, which is in harmony with the results obtained for the other members of the series (see following paper). UNIVERSITY COLLEGE, DUNDEE.

ISSN:0368-1645    

DOI:10.1039/CT9017901191

出版商:RSC    

年代:1901

数据来源: RSC

摘要:

WALKER AND LVMSDEN : N-DECANEDICARBOXYLIC ACfD. 1107 CXXVII.-n-Decalzedicwboxylic Acid. By JAMES WALKER and JOHN S. LUMSDEN. THE following research was begun by us more than two years ago, and was then completed as far as the electrosgnthesis of rz-decanedicarb- oxylic acid from pimelic acid. The properties of the electrosynthetic acid differed, however, in so many particulars from those of the acid pre- pared by Nordlinger from his bromundecylic esters (Ber., 1890, 23, 2357 ; compare preceding paper), that, notwithstanding their general resemblance, me wore uncertain of the identity of the two acids, and were compelled to undertake a revision of Nordlinger’s work. I n the1198 WALKER AND LUMSDEN : N-DECANEDICARBOXYLIC ACID. meantime, an abstract of a paper by Kornppa appeared (Chern.Centr,, 1899, ii, 1016 ; from Festsclwift. Polyt. Instit. Helsingfors, April, 1899), in which it mas stated that he had prepared the electrosynthetic acid, and found its properties to be identical with those of the acid described by Nordiinger. We were at a loss to account for. this divergence from our own results, and awaited the details of Komppa's research, These have now been published (Bey., 1901, 34, SOS), and as we have, mean- time, prepared n-decanedicarboxylic acid from w-brornundecylic acid, me are at present in a position to make a direct comparison of this with our electrosynthetic acid, and also to compare both of these with the acids of Nordlinger and Komppa. As Komppa performed the electrolysis of ethyl potassium pimelate with a comparatively small quantity (6-5 grams) of material, and investigated none of the intermediate and subsidiary products, we here give a brief account of the preparation and electrolysis of ethyl potassium pimelate, as carried out by ourselves. Prepaycction of n-pirnelic Acid fi.onz 8cdicyh'c Acid.When salicylic acid is reduced by sodium in amyl alcohol, a COh- siderable proportion of it is converted into n-pimelic acid according to the empirical equation, C7H60, + H,O + 4H = C,H,,O, (Einhorn and Lumsden, AnBaEert, 1895, 286, 257). This reaction forms a convenient method of preparing 92-pimelic acid when carried out according to the following directions. Salicylic acid is boiled for 2 hours with five times its weight of dried fusel oil and half its weight of sulphuric acid. By this means, i t is mostly converted into esters, which are more readily reducible than the acid i€self, After cooling, t>he sulphuric acid is washed out from the oil with water, and finally with dilute sodium carbonate solution (which also removes a little untransformed salicylic acid), and the residual liquid is then dried over anhydrous sodinm sulphate.The solution is diluted with fusel oil until it occupies 100 C.C. for each 7 grams of salicylic acid originally taken. The reduction is then effected as follows. A litre flask of Jena glass is fitted with a Y-shaped adapter of 11alf.inch bore, the sloping limb of which is attached to a reflux coudenser. A dropping-funnel is fitted by means of a cork into the upright limb, and can be removed as required for the introduction of pieces of sodium.Ten grams of sodium in large pieces and 50 C.C. of fusel oil are heated in the flask on an asbestos air-bath t o the boiling point of the alcohol, and the solution of salicylic esters is then dropped in slowly from the tap funnel until 150 C.C. have been added. When the first chargeof sodium is reducedWALKER AND LUMSDEN : N-DEcANEDIcARBOX~?LIC ACID, 1198 to a small bulk, a second charge of 10 grams is added, and the heating continued until all the sodium disappears. The operation lasts about 3 hours, and during this time the flask must be occasionally shaken, to prevent the sodium compounds which separate out from hardening on the walls of the flask. When the sodium has disappeared, the contents of the flask are cooled to a little below loo", and an equal bulk of water is added to decompose the sodium amyloxide and dissolve out the sodium salts produced by the reduction.The aqueous layer is separated from the oil, which is subsequently washed out twice with its own bulk of water, the aqueous extracts being added t o the original aqueous solution, The aqueous liquid is then boiled to reduce its bulk and to remove the fuse1 oil which it retains in solution. After cooling, the liquid is strongly acidified with hydrochloric acid. An oily acid separates a t once, and some salicylic acid crystallises out on standing. These are removed by filtration and rejected. The filtrate is then boiled down until sodium chloride begins to separate, when i t is cooled and thrice extracted Jtrith ether.The ether is distilled off from the extract, and the residue dissolved in a little boiling water, any oil which remains undissolved being filtered off. On cooling, a little salicylic acid usually separates, This is removed by filtration, and the filtrate concentrated by evaporation until pimelic acid begins to crystallise, out. The average yield of yimelic acid is 45-45 grams from 10.5 grams of salicylic acid. It is inadvisable to work with pure amyl alcohol, or with larger quantities than those given. As three or four reductions, however, can be carried on simultaneously, and the products worked up together, the preparation of a quantity of pimelic acid is not 60 tedious as might appear from the above description. Preparation and Electi*olysis of Ethyl Potassium Pimelate.Pimelic acid (100 grams) mas converted into the diethyl ester (103 grams obtained) by means of ethyl alcohol and hydrochloric acid. The diethyl ester thus prepared was dissolved in twenty- five times i t s weight of ethyl alcohol, and half saponified at the ordinary temperature by treatment with the calculated quantity of potassium hydroxide in four successive portions (compare Walker, Trans., 1892, 51, 710). Ten grams of the ester were recovered un- changed, so that 10 grams had been converted into the dipotassium salt, and 80 grams into the ethyl potassium salt. Ethyl Hydrogen Pimelate, C0,H*[CH,],*C02Et.-A small quantity of the aqueous solution of the mixed potassium salts was acidified with hydrochloric acid, and the liberated acids extracted with ether.The acids were then converted into the corresponding calcium salts by1200 WALKER AND LUMSDEN : N-DECANEDICARBOXYLIC ACID. warming with water and precipitated calcium carbonate until the aqueous solution became neutral. Ethyl calcium pimelate is freely soluble in water (less so at the boiling point than a t the ordinary temperature), whereas calcium pimelate is sparingly soluble. The calcium salts were thus to it large extent separated from each other. Ethyl hydrogen pimelate, separated from the solution of ethyl calcium pimelate by acidification, is a colourless oil which does not solidify at Oo. I n this respect it resembles ethyl hydrogen adipate, and differs from ethyl hydrogen suberate and ethyl hydrogen sebate, which are solids melting a t 18" and 3S0 respectively (Walker, Zoc. cit., p.713). It is easily miscible with the ordinary organic SoIvents, but only sparingly soluble in water. 0.1 gram required 10.9 C.C. N / 2 0 HCl for neutralisation ; replaceable H = 0.54 per cent. ; calculated for CO,Et*[UH,],*CO,H replaceable H=0.53 per cent. The substance was therefore nearly free from pimelic acid. A solution which contained 75 grams of ethyl potassium pimelate, together with dipotassium pimelate as impurity, was dissolved in 100 C.C. of water, and electrolysed with a stout platinum wire as anode, the current averaging 10 amperes and the temperature being kept below 30°. In this way, 26 grams of an oil were obtained which con- sisted mainly of the ethyl esters of two acids formed at the anode in the normal manner as follows : 2C0,Et*[CH2],*C0, = CO,Et*[CH,],,*CO,Et + 2C0,.Ethyl n-decnnedicnrboxylate. CO,Et*[CHz],*CH:CH, + CO,Et*[CH,],*CO,H + CO,. 2C02Et*[CH,],*C02 = Ethyl n-pentenecarboxylate. The esters were dissolved out in ether, washed, dried with calcium chloride, and after evaporation of the ether distilled under reduced pressure, As usual, the esters separated roughly on fractionation into a low boiling and a high boiling portion, which were saponified separately with alcoholic potash. On acidification, the portion of lower boiling point yielded an oily acid containing a little solid, and that of higher boiling point a solid acid contaminated with a little oil. n-PelztanecadoxyZic Acid, CH,:CH*[CH&*CO,H.-The liquid acid, which mas only obtained in small quantity, was found to be easily volatile with steam, and was therefore separated from the solid acid by steam distillation. The oil thus obtained boiled between 215' and 280°, and did not solidify in a good freezing mixture.It mixed readily with the ordinary organic solvents, but was comparatively slightly soluble in water. It absorbed bromine in chloroform solution, and its sodium salt a t once decolorised potassium permangnnate in aqueous solution a t the ordinary temperature.WALKER AND LUMSDEN : N-DECANEDICARROXYLIC ACID. 1201 0,1264 gave 0.2942 (20, and 0.1016 H,O. C= 63.5 ; 1% = 8.9. C,H,,02 requires C = 63*2 ; H = 8.8 per cent. The small quantity at our disposal precluded further purification, but the above data are sufficient to show that the acid is wpcntene- carboxylic acid, a normal product of the electrolysis.n-DecunedicaYboxyZic Acid, CO,H*[CH,],,*CO,H.-The solid acid obtained from the fraction of higher boiling point, which constituted by far the larger proportion of the mixed esters, was freed from the liquid acid by steam distillation. It was finally dissolved in much boiling water, from which i t separated on cooling in the form of pearly scales melting at 126*5-127". Komppa gives 125.5-127O as the melting point of his electrosynthetic acid. 0-1551 gave 0.3555 CO, and 0.1320 H,O. 0,1428 barium salt gave 0.0902 BaSO,. C = 62.52 ; H = 9.46. C,,H2,0, requires C = 62-61 ; H = 9 5 6 per cent, C1,H2,O4Ba requires Ba = 37.5 per cent. Ba = 37.2. The acid is thus the normal product of the electrosynthesis.Prepration of n- Decanedicccrbox3lic Acid frcm o-Bromundecylic Acid. Nordlinger states that Brunner's bromundecylic acid cannot be converted by the action of potassium cyanide into the corresponding cyanundecylic acid. H e consequently employed for this transforma- tion the methyl and ethyl esters obtained by the addition of hydrogen bromide to the corresponding esters of undecylenic acid (see preceding paper). In view, however, of the comparative stability of the o-bromo- acid, we considered i t probable that replacement OF bromine by cyanogen could be effected in a neutral salt of the acid ; this we found to be the case. 5.3 grams of w-bromundecylic acid mere dissolved in 20 C.C. of normal caustic soda solution, 1.6 grams of potassium cyanide mere added, and the liquid waq then made up to 100 C.C.The solution was heated on the water-bath for 12 hours, during which time a considerable amount of a brownish, flocculent precipitate was deposited. This was removed by filtration, and the fi1 tritte saturated with hydrogen chloride. An oily cyano-acid eeparnt ed, which partially solidified on cooling. After heating the mixture on the water-btth in a reflux apparatus for 3 hours, the oil mas completely transformed into a cake of small crystals. The mixture on cooling deposited more crystals, which mere filtered off together with the original cake, washed, and recrystallised from boiling water. The substance obtained melted at 123--124O, but on subsequent recrystallisation, the melting point rose t o 126*5*.VOL. LYXIX. 4 N1202 WALKER AND LUMSDEN : N-DECANEDICARBOXY IJC ACID. Nordlinger gives 124*5-125*5° for his acid. substance were thus obtained. 1.65 grams of the pure 0.0900 gave 0.2060 CO, and 0.0776 H,O. C12H2,0, requires C = 62.61 ; H = 9.56 per ccn t. 0.1 458 required 25-1 C.C. N/20 NaOlI for rreutralisation. C: = 62.42 ; H = 9-58, Replace- able H = 0.861. Calculated for C,,H,,(CO,H), i*eplaceable H = OmS69. On direct comparison, the acid was found to be identical in every respect with the electrosynthetic acid. This fact is conclusive evidence of the normal structure of undecylenic acid, and affords additional confirmation of t h e formulie ascribed to the various substances men- tioned in the preceding paper. Nordlinger obtained a very impure product from the esters which he employed, arid consequently a very small yield of the purified decanedicarboxylic acid.On the other hand, the yield from the sodium salt of w-bromundecylic acid is equal to 40 per cent. of the theoretical, and the substance is a t once obtained in a state approximating to purity. SoZubiZity of n-Decanedictci.box~Z~c Acid.--The chief point in which Nordlinger and Kompps have obtained results in absolute discordance from ours is the solubility of the acids in water. This point is of importance, a s it affords t h e only available numerical means (besides the melting point) for a comparison of their acid with ours. The solu- bility of our electrosynthetic acid is exactly that of the acid we pre- pared from o-bromundecylic acid, and yet i t is entirely divergent from the solubility of the acids obtained in similar ways by Nordlinger and Komppa, as the follomiog nnmbers show : 100 parts of water dissolve a t 2 3 O .. . .. . 0.005 0.0059 0.003 Niirdlingcr. Komppa. W. and I,. 9 , I 9 ,, 100 O...... 0.113 0.105 0.368 It thus appears that our acid is less soluble at 2 3 O , and more soluble a t looo, than NGrcllinger’a and Komppa’s acids. The difference in solubility at the lower temperature need not, however, be insisted on, as the magnitude measured is very small. On the other hand, the difference at 100’ is far too great to be explained by m y ordinary experimental error. Thus Komppn states that 100 C.C. of t h e solution saturated at 100’ required 9.2 C.C. of decinormal soda solution for neutralisation, whilst a similar quantity of the saturated solution of our acid would require more than 30 C.C.As we found the solubility of the acid near the boiling point varied very rapidly with the temperature, me determined the soh- bility at different intermediate temperatures, with the following results :WALKELL AND LUMSDKN : N-DECANEDICARBOXYLIC ACID. 1203 Parts dissolved by 100 Temperature. parts of water. a 3 O 0.003 98 0.005 51 0.027 84 0.1 20 98 0.306 100 0.368 . I n each case, the solubility was determined by titrating a weighed quantity of the saturated solution by means of a twentieth-normal solution of caustic soda which had been standardised against the acid itself, phenolphthalein being used as indicator. A t 54" and above, the filtration was conducted by means of a small suction filter im- mersed in the liquid itself.The accompanying curve shows that our acid has a solubility a t 82' equal to that given by Komppa and Ntirdlinger for 100'. S'ol?cb%ty curve of iiorinal decanedknrboxylic ucid. 29 so Tcnzpcmt w e . It is well known that the solubility of the members of the series of normal saturated dibasic acids with an even number of carbon atoms is smaller than the solubility of the members with an odd number of carbon atoms. This regulwity persists with the higher members of the series, as we see from the following table, which incorporates the solubility results for the ordinary temperature given in this aGd the preceding paper. Solubility (parts Acid (even). in 100 of water). Acid (odd). ..................4.5 C7HI2O4 Pimelic C:lH,,O, Azelnic 0.01 4 C,, H,30, Nonanedicarboxylic C,,H 240, Brassy lic Adipic C61-I,,0, 1.5 Suberic C!,H,,O, 0.14 o.12 Sebacic Cl0 H,80, 0 -01 Decanedicarboxylic.. , C12 H,,04 0 *003 .oo4 .................. .................1204 MACKENZIE: THE ACTlON OF SODIUM MEETHOXIDE ON Salts of n-Decumedicarhoxylic Acid.-The description given by Nordlinger of the salts of his acid differs in many poiuts of detail from what we found with the acid we had prepared, although there is a general resemblance in behaviour. For our experiments, we used a solution containing 0-64 gram of sodium salt in 100 C.C. With calcium nitrate, this gave a flocculent pre- cipitate which settled readily ; no further precipitate appeared when the clear liquid was boiled. Nordlinger states that both the calcium and barium salts are less soluble in boiling than in cold water. This is certainly the case to R slight extent with the barium salt, but we were unable to detect, in the case of the calcium salt, any appreciable difference in solubility a t the ordinary temperature and at the boiling point. Strontium nitrate gave no precipitate at the ordinary temperature with the above solution, but gave a very slight precipitate on boiling. Magnesium nitrate gave no precipitate at any temperature ; but a solution containing four times as much sodium salt gave a pre- cipitate with this reagent on standing. Mercuric chloride gave a bulky, finely divided, precipitate, which did not coagulate readily on heating. Nordlinger states that his acid gave no precipitate with mercuric chloride, but only a slight opalescence. Notwithstanding these differences, we are inclined to think that both Nordlinger and Komppa had n-decanedicarboxylic acid in their hands, Niirdlinger’s acid having been derived from a quantity of w-bromundecylic ester, which must have been contained in the ester he prepared from undecylenic ester. The expenses of this and of the yrecediug research were partially defrayed by a grant from the Research Fund of the Society. UNIVEESITY COLLEGE, DUNDEE.

ISSN:0368-1645    

DOI:10.1039/CT9017901197

出版商:RSC    

年代:1901

数据来源: RSC