Preparation of 1,3,5-trinitrobenzene
1,3,5-trinitrobenzene is prepared from 2,4,6-trinitrotoluene by oxidizing with potassium dichromate.
A round bottom flask is charged with 221 grams of concentrated sulfuric acid and 22.7 grams of 2,4,6-trinitrotoluene are slowly added with the gentle heating to 40° C. During the next 1 hour period 35.3 grams of potassium dichromate are added in small portions tothe mixture of concentrated sulfuric acid and 2,4,6-trinitrotoluene, by monitoring temperature, which should not exceed 45-55° C. After the addition of potassium dichromate is completed the reaction mixture is kept for 2 hours at 50-55° C. Then the reaction mixture is poured in crushed ice and precipitated 2,4,6-trinitrobenzoic acid is separated by filtration and washed with distilled water. 2,4,6-trinitrobenzoic acid is placed in the flask containing 100 ml of 15% warm (30-35° C) sodium hydroxide solution and the color of the reaction mixture changes to faint red. Few drops of acetic acid are added and the mixture is filtered, if necessary, from unchanged trinitrotoluene. The filtrate is mixed with 5 ml of acetic acid and refluxed by gentle heating with stirring at 95-98° C. At this point 2,4,6-trinitrobenzoic acid decomposes forming carbon dioxide and 1,3,5-trinitrobenzene. Gentle heating should be applied in order to avoid over foaming. The 1,3,5-trinitrobenzene separates in a crystalline condition and floats on the surface of the reaction mixture as a frothy layer. The evolution of carbon dioxide gas ceases after about 90 minutes and heating with stirring is continued for additional 45 minutes. The completion of reaction could be monitored by adding sulfuric acid to the filtrate. If a precipitate is produced, the reaction is not complete and further decarboxylation by heating should be continued. When the decarboxylation reaction is complete the flask is cooled to room temperature and crystals 1,3,5-trinitrobenzene are filtrated. 1,3,5-trinitrobenzene is washed with distilled water and crystallized from acetic acid. The melting point of pure 1,3,5-trinitrobenzene is 121-120° C.
Орлова Е.Ю. – Руководство к лабораторному практикуму по получению нитросоединений. – М., 1969, 87-89.
By another method a mixture of 30 g of purified 2,4,6-trinitrotoluene and 300 ml of concentrated sulfuric acid is introduced into a tall beaker, which stands in an empty agateware basin, and the mixture is stirred actively by means of an electric stirrer while powdered sodium dichromate (Na2Cr207 · 2H2O) is added in small portions at a time, care being taken that no lumps are formed and that none floats on the surface of the liquid. The temperature of the liquid rises. When it has reached 40° C, cold water is poured into the basin and the addition of sodium dichromate is continued, with stirring, until 45 grams has been added, the temperature being kept always between 40° C and 50° C. The mixture is stirred for 2 hours longer at the same temperature, and is then allowed to cool and to stand over night, in order that the 2,4,6-trinitrobenzoic acid may assume a coarser crystalline form and may be filtered off more readily. The strongly acid liquid is filtered; the solid material is rinsed with cold water and transferred to a beaker in which it is treated with warm water at 50° C sufficient to dissolve all soluble material. The warm solution is filtered, and boiled until no more 2,4,6-trinitrobenzene precipitates. The crystals of 1,3,5-trinitrobenzene growing in the hot aqueous liquid often attain a length of several millimeters. When filtered from the cooled liquid and rinsed with water, they are practically pure, almost colorless or greenish yellow leaflets, m.p. 121-122° C.
Chemistry of Powder and Explosives, by T. L. Davis, 135 1941
1,3,5-trinitrobenzene, 2,4,6-trinitrobenzene, sym-trinitrobenzene
1,3,5-TRINITROBENZENE, sym-Trinitrobenzene, Trinitrobenzene, s-Trinitrobenzene, Benzite, syn-Trinitrobenzene, 99-35-4, Trinitrobenzeen, Trinitrobenzol, Benzene, 1,3,5-trinitro-, Benzene, trinitro- (wet), RCRA waste number U234, Trinitrobenzeen [Dutch], Trinitrobenzol [German], symmetric Trinitrobenzene, NSC 36931, TNB, RCRA waste no. U234, Benzene,1,3,5-trinitro-, CCRIS 3093, HSDB 6005, UATJOMSPNYCXIX-UHFFFAOYSA-N, EINECS 202-752-7, UN0214, UN1354, AI3-08924, T5315062, Trinitrobenzene, dry or wetted with < 30% water, by mass, 2,4,6-trinitrobenzene, Trinitrobenzenes, Trinitrobenzene, dry, Trinitrobenzene, wet, 1,5-Trinitrobenzene, 1,3,5-Trinitrobenzol, 1,3,5-trinitro-benzene, WLN: WNR CNW ENW, AC1L1OR7, AC1Q5AL7, Ex241, SCHEMBL212845, UNII-2H75703R1X, CHEBI:48113, CTK3J8219, MolPort-001-779-778, NSC36931, AR-1H8899, NSC-36931, AKOS001092692, 2H75703R1X, MCULE-9062988700, RTR-032492, LS-32258, TR-032492, FT-0654261, S01-0300, Trinitrobenzene, wetted with not <30% water, by mass, 3B3-046352, Trinitrobenzene, dry or wetted with <30% water, by mass, Trinitrobenzene, dry or wetted with <30% water, by mass [UN0214] [Explosive 1.1D], Trinitrobenzene, dry or wetted with <30% water, by mass [UN0214] [Explosive 1.1D], Trinitrobenzene, wetted with not <30% water, by mass [UN1354] [Flammable solid], Trinitrobenzene, wetted with not <30% water, by mass [UN1354] [Flammable solid], 856948-61-3
Benzene,3,5-trinitro-, CID7434, 2-(4-methylpiperazin-1-yl)ethanamine, T0496, C029222, 6323-06-4