Theoretical Study on Pyrolysis and Sensitivity of Energetic Compounds. Part I: Simple model molecules containing NO₂ Group

Abstract

Abstract UHF (Unrestricted Hartree‐Fock) Molecular Orbital calculations have been first performed for studying the pyrolysis mechanism of five compounds (nitromethane, methyl nitrate, nitroamine, methyl nitroamine and dimethyl nitroamine) containing NO 2 group as the simple models of organic explosives by using PM3 and AM1 methods. The potential energy curves and activation energies of the five pyrolysis reactions (into radicals) have been obtained. The activation energies are consistent with the experimental impact sensitivity of these three kinds of explosives: C‐nitro < N‐nitro < O‐nitro compounds. It is found that there is a parallel linear relationship between the bond orders of NNO 2 bond in the molecules of three nitroamine compounds and the activation energies of their initiation reactions breaking NNO 2 bond. The obtained correlation coefficients between bond orders and activation energies from PM3 and AM1 calculations are 0.9962 and 0.9999, respectively.