Thermal decomposition of arylnitramines

Abstract

The thermal decomposition of various substituted N-methyl-N-nitroanilines dissolved in indifferent solvents and piperidine has been investigated. Activation volumes and product analyses support evidence that the rate-determining step is the reversible homolysis of the nitramine bond. The activation volumes range from +18 to +36 ml mol^–1. A non-linear Hammett relationship is attributed to an increase in secondary caged reactions, namely rearrangement and oxidation. Arylnitramines with electron-donating substituents yield greater amounts of the thermal rearrangement products than those with electrondeactivating groups at ambient pressures. Decomposition of arylnitramines with electron-donating substituents under high pressures (ca. 1.2 GPa) favours caged reactions over separative diffusion.