2.4.6- trinitrotoluene impurities

H. Kramer, S. Semel J.E. Abel, Trace Elemental Survey Analysis of Trinitrotoluene , PATR 4767 (1975) (An evaluation of the applicability of spark source mass spectrometry and thermal neutron activation for the detn of origin-related trace elemental impurities in TNT) 10) C. Ribando J. Haber-man, Origin-Identification of Explosives Via Their Composite Impurity Profiles I. The... 

Ref C. Ribaudo J. Haberman, Origin— Identification of Explosives Via Their Composite Impurity Profiles, I, The Relation of the Origin of Military Grade TNT to its Mono-, Di-, and Trinitrotoluene Isomer Impurities , PATR 4768 (1975)... 

The trinitrotoluene is separated from the mother liquor, washed with w, and then treated with a sulfite soln called Sellite which extracts undesirable isomers and impurities, leaving purified a-TNT. The TNT is washed, solidified, flaked, and finally shipped out in boxes... 

The temperature of explosive decomposition of trinitrotoluene very much depends on the compound purity. The table below shows the influence of various impurities on this compound. 

The most important of these explosive isomers is the alpha-trinitrotoluene, known as TNT. In crude, commercial TNT, 4 to 5% of impurities are present, consisting mainly of. a mixture of beta-, or 2,3,4-, and gamma, or 3,4,6-trinitrotoluenes. These impurities may be removed by treating the crude TNT with an aqueous solution of sodium sulfite. Ac-, cording to Davis (Ref 3) the beta- and gamma-isomers react with lead oxide in alcohol to form lead dinitrocresolates, while alpha-TNT remains unaffected under similar conditions Refs 1) M. Copisarow, Chem News 118, 13-14 (1919) CA 13, 791 (1919) 2) M.M. Kos-tevitch, Trinitrobenzene Trinitrotoluene, Paris (1927) 3) Davis (1943) p 147... 

TNT is the abbreviation of the aromatic nitrated aromatic compound 2,4,6-trinitrotoluene. It is a pale-yellow crystalline solid that was first synthesized in 1863 by the German chemist Joseph Wilbrand (1811—1894), but it was not immediately used as an explosive. TNT is made by nitrating toluene using nitric acid, sulfuric acid, and oleum (a mixture of sulfuric acid and S03). Nitration of toluene occurs in stages, with the nitro units added sequentially in a stepwise process as the reaction proceeds. The last nitro unit is accomplished by using oleum (SO, dissolved in sulfuric acid). After nitration, unused acids are recycled, and the product is washed with sodium sulfite and water to remove impurities. 

Ref 6) and Clift Fedoroff (Ref 7) described prepn of MeTetryl from beta- and gamma-Trinitrotoluene isomers always present as impurities on the surface of crysts of etude aipha-TNT. The jS and y isomers can be removed by washing the crysts of crude a TNT with 8% aqueous Na sulfite soln (called Sellite). This converts the isomers into water-soluble dinitrotoluene sulfonates. Then, on their treatment with me thy famine the following reaction takes place ... 

See 2,4,6-Trinitrotoluene Added impurities See other METAL OXIDES, OXIDANTS... 

The low melting point of a- trinitrotoluene is due mainly to the presence of trinitrotoluene isomers, and to a lesser degree, to the presence of other impurities, such as trinitrobenzene, trinitrocresol, dinitrotoluene. 

In the opinion of Koelsch [119], Curshmann [120], Van Diun [121], and others, pure a- trinitrotoluene is non-toxic. They consider that impurities present in TNT, such as dinitrobenzene Mid tetranitromethane, Me responsible for any toxic effects caused by TNT. According to Koelsch, idiosyncrasy manifested by poisoning symptoms, has heen met with... 

In industrial practice, losses of crude TNT in the sulphitation process amount from 6 to 8%. Out of this 2%-3. 5% is ascribed to the loss of a- trinitrotoluene and 3.5-4.5% to that of unsymmetrical isomers and other impurities, such as tetrani-tromethane (p. 339) and trinitrobenzene which is easily soluble in sodium sulphite, forming addition products. 

As soon as the temperature falls to 75°C the nitrator contents should be cooled vigorously and simultaneously the speed of rotation of the stirrer should be reduced to avoid pulverizing the crystals. When the temperature has fallen to 30-35°C cooling is discontinued, and almost pure a- trinitrotoluene is filtered off. If the Process of crystallization is properly carried out most of the impurities will remain in the acid. 

The TNT is filtered off in a vacuum tank and washed, first with 70% and then with 45% sulphuric acid, each used in the proportion of 800 kg for 1000 kg of TNT, and finally several times with water. By using acid of a gradually reduced concentration for washing a very effective removal of oily impurities of DNT and of isomers of trinitrotoluene can be achieved. 

The residue left after the solvent - alcohol (in the earlier crystallization method) or xylene (from the washing technique) - has been distilled off, is a semi-solid substance consisting of a- trinitrotoluene, its isomers, dim trot oluenes and other nitro compounds, all of them found as impurities in TNT. 

Trinitrotoluene (also known as y-TNT) is one of the main impurities in military and commercial grades of TNT. Chick and Thorpe (1971) characterized two polymorphs. Form I (mp 376.2 K) may be obtained by recrystallization from alcohol or solidification of the melt. Form II (mp 347.2 K) is produced in small quantities with difficulty from an undercooled melt. It readily converts to Form I by mechanical perturbation or even spontaneously. Chick and Thorpe also determined latent heats of fusion, entropies of fusion, specific heats, IR spectra. Due to the conversion induced by grinding no X-ray data were presented for either form. No crystal structures have been reported. 

Unsymmctrical isomers of trinitrotoluene and by-products of nitration of toluene Teiranitromethane While compound Impurities of TNT... 

Tetranitromethane is an oily liquid with a vapor pressure less than that of water. It occurs as an impurity in 2,4,6-trinitrotoluene (TNT). The primary routes of potential human exposure are inhalation and dermal contact. Historically, exposure to tetranitromethane presumably occurred during the manufacture and use of TNT. 

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