Impurities in TNT

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... 

The more advanced instrumental methods of analysis, including GC, for the detection and identification of expls are presented (Ref 90) Pyrolysis of expls in tandem with GC/MS was used for the identification of contaminant expls in the environment (Ref 108). Isomer vapor impurities of TNT were characterized by GC-electron capture detector and mass spectrometry (Ref 61). Volatile impurities in TNT and Comp B were analyzed using a GC/MS the GC was equipped with electron capture and flame ionization detectors (Ref 79). The vapors evolved from mines, TNT, acetone, toluene, cyclohexanone and an organosilicon, were analyzed by GC/MS (Ref 78). Red water produced by the sellite purification of crude TNT was analyzed by GC/MS for potentially useful organic compds, 2,4-dinitrotoluene, 3- and 4-sulfonic acids (Ref 124). Various reports were surveyed to determine which methods, including GC/MS, are potential candidates for detection of traces of TNT vapors emitted from land mines factors influencing transportability of TNT vapors thru soil to soil/air interface are dis-... 

Impurities in TNT , Rept D-1086-FR-XD, US Naval Ordn Test Sta, China Lake (1952)... 

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. 

DNT (impurities in TNT) were detected by NMR when they had been missed by analysts using TLC. Qualitative and quantitative determinations of small amounts of additives or impurities have been used to differentiate between homogeneous explosives originating from different sources. Characteristic impurities may allow the analyst to determine the synthetic route used to produce the explosive. 

Murrman, T.F. Jenkins D.C. Leggett, Composition and Mass Spectra of Impurities in Military Grade TNT Vapor , Special Rept 158,... 

Table 4 gives details of some relevant physical and thermal properties of a range of common explosives that have been encountered in terrorist bombs. It should be noted that DMNB (2,3-dimethyl-2,3-dinitrobutane) is one of the taggants added to plastic explosives under the Montreal Convention on marking of plastic explosives. Dinitrotoluenes are frequently added to blasting gelatine as a minor component and are also found in TNT as a significant impurity. 

Where the maintenance of a clear channel between sprue and the slowest freezing part of a charge is impractical, cavitation is avoided by casting charges in layers, each of which is allowed to crust over before pouring the next TNT melts at 81°. It forms eutectics with RDX, Tetryl (68°), PETN (76°), and other impurities in the mix and makes these materials more soluble at higher temps. Thus, there is a general tendency for the solid content and, hence, the apparent viscosity of most castable mixts to decrease as the temp is increased. However, a reversal of the tendency toward the reduction in viscosity has been noted in Comp B when it heated above 100°... 

The principal impurities in item (1) were the undesirable isomers of TNT DNT their presence lowered the mp (Setting Point) of a-TNT from 80.75° to 80.2° (Specification grade) and could lower it much more. On castin g TNT in the shell, the outside of the cast solidified first because or the cooling effect produced by the metal walls of the shell, while the center portion of the cast solidified last, because it was somewhat insulated. As the result of this cooling, the mixture that sol i di f i ed - a C the outside contained a large proportion of high melting components, while the portion that solidified in the center core contained the bulk of the impurities because they solidified at a lower temperature. 

Regarding the exudation due to impurities introduced by technical AN in TNT mixtures,... 

Post-WWH investigations conducted at Picarinny Arsenal showed that a dark reddish-brown exudate collected ftom 105mm shells loaded with TNT consisted principally of a mixture of a-TNT with some /3- and yTNT and, sometimes, traces of 2,4-DNT and other products of nitration of impurities in toluene, it is also probable that alcohol present in "NRC" sealing compound and/or other extraneous material might favor exudation. 

The system ammonium nitrate, aluminium, nitro compound (e.g. TNT) would be expected to undergo gradual decomposition, e.g. that in stored shells and bombs filled with such mixtures changes would occur, leading to the oxidation of the aluminium. Obviously, a mixture containing oxidized aluminium has lower explosive power than the same mixture containing metallic aluminium. It was therefore very important to determine the mechanism of the oxidation of aluminium. It became apparent that this is caused by impurities in the ammonium nitrate, not by the... 

Impurities Present in TNT Prepared by Continuous Nitration and Purification a... 

Chromatographic Detection and Estimation of Trace Isomer Impurities in Military Grade TNT , PATR 4963 (1976) 123) M. Halik C. 

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... 

Oxidation leads to the formation of di- and tri-nitrocresols, impurities frequently met with in TNT. Nitrocresols are mainly formed during the nitration of toluene to mononitrotoluene (Noelting and Forel [11]). If they have not been removed from mononitrotoluene by washing with alkalis, they undergo either further nitration to trinitrocresol, or oxidation to oxalic acid. Trinitrocresol may be removed from TNT by mild alkali washing (e.g. with a NaHC03 or a sodium sulphite solution). 

Hydroxynitro acids (I), (II) and (III) are (according to Schmidt) washed from the crude TNT and are present in the wash-waters. Trinitrobenzoic acids remain in TNT as impurities. The trinitrobenzoic acids formed are readily decarboxylated. C02 is evolved and only trinitrobenzenes remain in TNT as its impurities. 

The break-down of the molecule, and the loss of the methyl group, may lead to the formation of tetranitromethane during the nitration process. This substance is always encountered in TNT as an impurity, and its presence can be established by its characteristic smell reminiscent of that of nitrogen oxides. 

The exudation process is a modified purification by crystallization. At present it is applied to purify grade m TNT and to recover impurities present in TNT for use as TNT oil in the preparation of explosive compositions. The process may be carried out in two ways. 

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