THERMAL-DECOMPOSITION OF ARYLNITRAMINES

The thermal decomposition of various substituted N-methyl-N-nitroanili nes dissolved in indifferent solvents and piperidine has been investig ated. Activation volumes and product analyses support evidence that th e rate-determining step is the reversible homolysis of the nitramine b ond. The activation volumes range from +18 to +36 ml mol(-1). A non-li near Hammett relationship is attributed to an increase in secondary ca ged reactions, namely rearrangement and oxidation. Arylnitramines with electron-donating substituents yield greater amounts of the thermal r earrangement products than those with electron-deactivating groups at ambient pressures. Decomposition of arylnitramines with electron-donat ing substituents under high pressures(ca. 1.2 GPa) favours caged react ions over separative diffusion.