THERMAL-DECOMPOSITION OF ENERGETIC MATERIALS .61. PERFIDY IN THE AMINO-2,4,6-TRINITROBENZENE SERIES OF EXPLOSIVES

The numerous electronic, molecular, crystal, and explosive variables in the series 1,3,5-trinitrobenzene (TNB), 2,4,6-trinitroaniline (MATB), diamino-2,4,6-trinitrobenzene (DATB), and triamino-2,4,6-trinitrobenzene (TATB) give 153 nearly linear correlations. While some of these positive correlations have been cited previously as important, the molecular mechanism of the trend in the shock and impact sensitivity remains unclear because these correlations disguise the fact that significant differences exist in the critical thermal reactions. Arrhenius data suggest that C-NO2 homolysis is the initial decomposition reaction during impact and shock initiation in all cases. The lower activation energy cyclization process of MATB, DATB, and TATB to furazan/furoxan products can be overstepped at shock and impact initiation temperatures. However, C-NO2 homolysis does not account for the trend in sensitivity because the activation energy is relatively insensitive to the ring substituents. The trend in energy released by the intermediate reactions as reflected in the gaseous product distribution of TNB, MATB, DATB, and TATB at 520-degrees-C appears to be important. The contribution to the total beat from the exothermic products (CO, CO2, HNCO) decreases and that from the endothermic products (NO, N2O, HCN) increases as NH2 groups are added.