98 xI.-2 4 6- ~~init.rotolyl.methylnitr.oamine. By OSCAR LISLE BRIDY and WILLIAM HOWIESON GIBSON. TRINITROTOLYLMETHYLNITROAMINE has been described by Blanksma (Rec. trav. chim. 1902 21 327) who prepared it by the nitration of 2 4 6-trinitromethyl-m-toluidine obtained by the action of methylamine on 2 4 6-trinitro-nt-tolyl methyl ether. The prepara-tion of this compound from 2 3 4- and 3 4 6-trinitrotoluenes has now been studied. In 2 3 4- and 3 4 6-trinitrotoluenes one of the nitro-groups is mobile and is readily displaced by treatment with amines. In the case of the latter compound Hepp (Annalen 1882 215 344) showed that it was the 3-nitro-group that was displaced. In the case of 3 4 6-trinitrotoluene it has been shown that the dinitro-toluidine obtained by the action of ammonia is the same as that obtained as the main product in the nitration of aceto-m-toluidide (Cook and Brady T.1920 117 751) and the synthesis of 2:4:6-trinitrotolylmethylnitroamine from 3 4 6-trinitrotoluene confirms the fact that the 3-nitro-group is also the mobile one in this com-pound. These trinitrotoluenes accordingly follow the rule given by Meldola (T. 1908 93 1659) for the mobility of groups in negatively substituted benzene derivatives 2 4 6-TRINITROTOLYLMETIIYLNITROAMINE. 99 When 2 3 4- and 3 4 6-trinitrotoluenes are treated with methyl-amine or dimethylamine the corresponding dinitromethyl-m-tolu-idines and dinitrodimethyl-m-toluidines are formed all of which form 2 4 6-trinitrotolylmethylnitroamine on nitration.In the case of the dinitromethyl-nt-toluidiues the first action of the nitrating acid apparently consists in the formation of a dinitro-nitroamine more energetic nitration resulting in a further nitro-group entering the ring. It has not been found possible to obtain 2 4 6-trinitromethyl-m-toluidine by direct nitration of either 2 4- or 4 6-dinitromethyl-nz-toluidine but it has been prepared by denitration of the nitroamine. In the case of the dinitrodimethyl-m-toluidines the intermediate trinitrodimethyltoluidine has not been obtained; these compounds are not acted on by nitric acid of density 1.4 and are completely nitrated with the elimination of a methyl group by nitric acid of density 1.5 or by a mixture of nitric and sulphuric acids. The reactions are summarisecl on p.100. E X P E R I M E N T A L . 2 3 4- and 3 4 6-Trinitrotoluenes.-T?.e nitration of m-nitro-tcluene is described by Hepp (Zoc. cit.). A mixture of 2 3 4- and 3 4 6-trinitrotoluenes is obtained and Drew ('I?. 1920 117 1615) has shown that about 7 per cent. of 2 :3 6-trinitrotoluene is also produced. Hepp separated the 2 3 4- aud 3 4 6-compounds by crystallisation from carbon disulphide. A more convenient method of preparation and separation than that described by Hepp is as follows. A mixture of 160 C.C. of nitric acid (D 1.42) and 340 C.C. of sul-phuric acid (96 per cent.) is added in small portions a t a time to 225 grams of m-nitrotoluene the temperature being kept in the neighbourhood of 50°. When all the acid has been added the mix-ture is slowly heated to looo on the water-bath and kept at this temperature for thirty minutes with frequent shaking.The mixture is then allowed to cool to 50° and separated. The oil is added slowly to a mixture of 180 C.C. of nitric acid (D 1.5) and 410 C.C. of sulphuric acid (96 per cent.). The mixture is warmed to 70° and kept a t that temperature for thirty minutes with frequent shaking, and then cautiously heated t o looo a t which temperature it is kept for one hour. 'The oil is separated from the acid while still hot run into cold water and washed by tshe injection of steam until free from acid. On cooling and keeping the oil sets to a pasty solid, which is collected and dissolved in boiling alcohol (about 100 C.C. of 95 per cent.spirit for 1 2 grams of the mixture). The solution is cooled to about 50° and seeded with a little pure 3:4:6-trinitro-E 100 I BRADY AND GIBSON : q g z x w I I 0"S 0 2 4 6-TRINITROTOLYLMETHYLNITROAMINE. 101 toluene and shaken vigorously. After two to three minutes a fair quantity of solid will have separated in the form of sandy crystals, which are a t once collected. The filtrate is precipitated with water, and the solid after being freed as much as possible from water by pressing dissolved in boiling glacial acetic acid (about 100 C.C. of acid for 50 grams of solid). The solution is cooled to about 60° a very small quantity of water added and a crystal or so of 2 3 4-trinitrotoluene. When a small quantity of solid has separated this is filtered off rapidly.The filtrate is diluted with water and the solid again crystallised from alcohol and so on. Some little experi-ence is required ,to judge the amount of solid which should be allowed to separate from the alcohol and acetic acid before filtering. The solid separating from alcohol should consist of sandy crystals (if fine needles separate the solution has been cooled too much and must be re-heated) which should melt not lower than 9 7 O and the solid from acetic acid not lower than 104O. With these limits fairly large crops of crystals can be obtained and the process is not unduly prolonged. The crops from alcohol are combined and crystallised from alcohol when 3 4 6-trinitrotoluene is obtained pure. The crops from acetic acid are again crystallised from-acetic acid and then from alcohol when 2 3 4-trinitrotoluene is obtained.In these final crystallisations the solutions may be allowed to become quite cold. In one experiment two portions of 225 grams of m-nitrotoluene were nitratad ; 620 grams of mixed trinitrotoluenes were obtained (84 per cent.).. Three crystallisations from alcohol and three from acetic acid followed by one crystallisation of the combined crops from alcohol and from acetic acid and alcohol respectively yielded 200 grams of pure 3 4 6-trinitrotoluene and 100 grams of pure 2 3 4-trinitrotoluene. 2 ; 4-Binitromethyl-m-toluidine.-Twenty grams of 2 3 4-trinitro-toluene are dissolved in 250 C.C. of hot alcohol and a solution of 7 grams of methylamine hydrochloride in a small quantity of water is added followed by 12 C.C.of ammonium hydroxide (D 0.880) drop by drop. As the ammonia is added the liquid darkens but rapidly turns to a clear orange colour. The mixture is then boiled for a few minutes cooled and water added cautiously until crystallisa-tion begins. The solid is washed with water to remove ammonium chloride and crpstallised from alcohol when 2 4dinitromethyl-m-toluidine separates in long flat orange needles melting a t 81°, readily soluble in hot and sparingly so in cold alcohol (Found, N = 19.7. 4 6-DinitrometI~yl-m-toluicZine.-'T'he preparation is the same as that of the above compound substituting 3 4 6-trinitrotolnene. C,H,O,N requires N = 19.9 per cent.) 102 RRADY AND GIBSON: Soon after the addition of the first drops of ammonia the compound begins to separate and the addition of water during cooling is unnecessary.4 6-Dl'nitromethyl-m- toluidine crystallises from boil-ing alcohol in which it is sparingly soluble in yellow needles melt-ing a t 1 7 3 O (Found N=20.0. C,H,O,N requires N=19.9 per cent.). This compound is possibly the same as that described by Wurster and Riedel (Ber. 1879 12 1800) who obtained it by the nitration of dimethyl-m-toluidine and found its melting point to be 168O. They regarded it however as a dimethyl derivative. 2 4-Dinitrodimetlzyl-m-tollticli?te,-Twenty grams of 2 3 4-tri-nitrotoluene in 250 C.C. of boiling alcohol are treated with 9 grams of dimethylamine hydrochloride and 1% C.C. of ammonium hydr-oxide. The mixture is diluted with two to three times its bulk of water and extracted with ether.Aft,er evaporating the dried ethereal extract 2 4-dinitrodimethyl-m-toluidine remained as an orange uncrystallisable oil. 4 6-Dinitrodimethyl-m-toluidine.-Ten grams of 3 4 6-trinitro-toluene in 100 C.C. of boiling alcohol are treated with 4.5 grams of dimethylamine hydrochloride and 6 C.C. of ammonium hydroxide. 'The mixture is cooled diluted slightly with water and the solid which separates crystallised from alcohol. 4 6-Dinitrodimethyl-m,-toluidine separates in yellow needles melting a t 107O more readily scluble i n organic solvents than the corresponding monomethyl derivative. This compound has been prepared by Wurster and Riedel (loc. c i t . ) by the nitration of dimethyl-m-toluidine in acetic acid solution.2 4 6-Trinitrotolylmethylnitroomine.-For the preparation of this compound 2 4- or 4 6-dinitro-methyl- or dimethyl-m-toluidines may be employed or a mixture of these obtained by the action of cIiide methylamine hydrochloride containing dimethylamine on a mixture of 2 3 4- and 3 4 6-trinitrotoluenes. Forty grams of the compound are added in small quantities a t a time t o 100 C.C. of nitric acid (D 1.5) warmed to 50°. Copious red fumes are evolved. particularly when dimethyl derivatives are present and when all the solid has been added the mixture is heated on the water-bath until the evolution of nitrous fumes ceases. The mixture is then cooled and water added when tri~iitrotolylmethylnitroamine sepa-rates out usually as an oil which solidifies on keeping.The solid is washed thoroughly and crystallised from alcohol to which a few drops of acetic acid have been added or from a mixture of alcohol and benzene. Trinitrotolylmethylnitroamine has a remarkable tendency to separate froin solvents in an oily condition and con-siderable difficulty is generally experienced in crystallising it. When the solid is fused it supercools t o a viscid mass in whic 2 4 6-TRINITROTOLYLMETHYLNITROAMINE. 103 crystallisation is very slow extending over months. Further in the presence of alcohol it is very sensitive to alkalis much more s3 than trinitrophenylmethylnitroamine and when crystallised from alcohol in glass vessels sufficient alkali is introduced to impart a faint violet tinge to the product.The addition of hard water to an alcoholic solution produces a marked colour in the product which crystallises out. 4 6-DinitrotoE~lmethylnitroarnine.-Five grams of 2 4dinitro-methyl-m-toluidine are added to 50 C.C. of nitric acid (D 1.42) warmed to 50°. The mixture is kept a t 50° for five minutes and then filtered while hot through glass-wool 20 C.C. of water are added and the whole is cooled when the nitroamine separates out. 4 6-Dinitrotolylmethyln~troamine crystallises from acetone or water in yellow plates melting and decomposing at 157O (Found, N = 21% C,H,O,N requires N = 21.9 per cent.). This compound on further nitration with fuming nitric acid yields trinitrotolyl-niethylnitroamine. The nitro-group attached t o nitrogen is removed by heating 1 gram with a solution of 0.5 gram of phenol in 20 C.C.of 80 per cent. sulphuric acid on the steam-bath for thirty minutes. The colour of the solution changes through blue to violet and finally brown. After cooIing the mixture is poured into water, the solid which separates washed with ammonia and crystallised from acetone and alcohol with the addition of animal charcoal, when 4 6-dinitromethyl-m-toluidine is obtained and identified by the method of mixed melting points. 2 4-Binitrotoliylrnethylnitroamin e.-This compound is prepared in a similar manner t o the above from 2 4-dinitromethyl-m-tolu-icline and crystallises from alcohol in very pale yellow needles melting a t 1 1 1 O (Found N=21*8. C,H,O,N requires N=21*9 per cent.). On further nitration with fuming nitric acid it also yields 2 4 6-trinitr~tolylmethylnitroamine but when treated with phenol and sulphuric acid 2 4 6-ti-initrornethyl-~n-toluidine is obtained and not 2 4-dinitromethyl-m-toluidine as would be expected.The possibility of this substance being 2 4 6-trinitrotolylmethyl-nitrosoamine was eliminated by the preparation of this compound, which was found t o be qnite distinct. Apparently the nitro-group in 2 4-dinitrotolylmethylnitroainine migrates to the ring so readily in the presence of sulphuric acid owing t o the para-position being free that this reaction takes place in preference t o the nitration of the phenol by the nitroamino-group. 2 4 6-trinitromethyl-m-t oluidine are suspended in 50 C.C. of glacial acetic acid and 30 C.C.of a 20 per cent. solution of nitrogen peroxide in 2 4 6-Trinitrotolylmet?~ylnitrosoamine.-Six grams o 104 2 4 6-TRTNTTROTOLYLMETHYLNITROABTTNE. acetic acid added. The mixture becomes slightly warm and the solid dissolves completely. Water is gradually added with thorough shaking when a buff granular precipitate is formed which is crystallised from alcohol. 2 4 6-T~initrotoZyZn~,.,tlr3/lnitrosoaminc crystallises in pale buff sandy crystals melting a t 120° (Found, N = 24.8. 2 4-Dinitrotolylmeth~lnitrosoamine and 4 6-Dinitrotolylmethyl-nitrosoamine .-These compounds are prepared in a similar manner to the above from 2 4- and 4 6-dinitromethyl-m-toluidine respec-tively. 2 4-Dinitrotolylmethylnitrosoamine crystallises from alcohol in colourless needles melting a t 65O (Found N=23-5.C,H,O,N requires N = 23.3 per cent.). 4 6-Dinitroto7yZmethyZ-nitrosoamine crystallises from alcohol in brilliant yellow needles melting a t 9 4 O (Found N=23*6. C,H,O,N requires N=23-3 per 2 4 6-Trinitromethyl-m-toluidine.-Lt was not found possible to regulate the conditions of nitration of the dinitromethyl-m-tolu-idines so as to obtain this coinpound directly. It may however be prepared from these compounds by nitrating them first to trinitro-tolylmethylnitroamine and removing the nitro-group attached t o the nitrogen atom. Five grams of the nitroamine are added in small portions a t a time to a solution of 4 grams of phenol in 50 C.C. of 80 per cent. sulphuric acid at 50° and the temperature is cautiously raised t o 90°. After heating a t 90° for thirty minutes the product is treated as in the deliitration of 4:6-dinitrotolyl-methylnitroarnine (see above) and the 2 4 6-trinitromethyl-m-toluidine crystallised from a mixture of acetone and alcohol. This compound is identical with that obtained by Blanksma (loc. cit.) by the action of methylamine on 2 4 6-trinitrotolyl methyl ether. The authors wish to express their thanks t o the Director of Artillery for perinission to publish these results. C,H,O,N requires N = 24.6 per cent.). cent .) . RESEARCH DEPARTMENT, ROYAL ARSENAL, WOOLWICH. [Received December 8th 1920