Triazole-based explosives

Analyses of the structures and properties of a large number of energetic materials reveal that a combination of amino and nitro groups in a molecule often leads to better thermal stability, lower sensitivity to shock and impact, and increased explosive performance because of an increase in crystal density. Such observations are attributed to both intermolecular and intramolecular hydrogen bonding interactions between adjacent amino and nitro groups. Some modern triazole-based explosives have been designed and synthesized with this in mind. 

Amino-1,2,4-triazole is a useful starting material for the synthesis of many 1,2,4-triazole-based explosives. Jackson and Coburn synthesized a number of picryl- and picrylamino-substituted 1,2,4-triazoles. PATO (99) is synthesized from the reaction of 3-amino-1,2,4-triazole (98) with picryl chloride (67). ° PATO has also been synthesized from the reaction of 3-amino-l,2,4-triazole with A,2,4,6-tetranitromethylaniline (tetryl). PATO has a low sensitivity to impact and is thermally stable up to 310 °C. PATO (VOD 7469 m/s) exhibits lower performance to TATB (VOD 8000 m/s) which is the common benchmark standard for thermal stability and insensitivity in explosives. 

K. -Y. Lee and M. M. Stinecipher, Propellants, Explosives, and Pyrotechnics, 14, 241 (1989). Handrick (Reference 2b) spoke of a salt link or correction of ca 67 kJ mol 1 associated with the formation of a salt from the reaction of an acid and base. From the enthalpy of formation of ethylenediamine from Pedley and of the ethylenediammonium salt of 3-nitro-l,2,4-triazol-5-one from the current reference, and the suggested salt link (x2), the enthalpy of formation of 3-nitro-l,2,4-triazol-5-one is predicted to be —135 kJ mol-1. This is in wonderful agreement with that reported in Reference 103. 

The two energetic A-nitroimide explosives (137) and (138) have been prepared from 1,2,3-triazole and 1,2,4-triazole respectively. These and other A-nitroimide-based energetic compounds are discussed in more detail in Section 6.11.3. 

An example of synthesis of N-fluoro-1,2,4-triazole was described in the patent of Strazdina and Grinstein [6, 17]. Here l-flnoro-3,5-dibromo-l,2,4-triazole 8 was obtained by treating the heterocyclic substrate with the hypohalous acid or its derivatives at -40 to -h50 C in water or an organic solvent in the presence of bases. Langlet and Oslmark in a patent [18] have described the application of isomeric fluoro-triazolones 9,10 as components of explosive compositions, but the data on the synthesis of these substances have been not reported. 

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