The explosive RDX (1,3,5-trinitrohexahydro-s-triazine) is thought to decompose by homolytic N-N bond cleavage, among other possible initiation reactions. Quantum chemistry calculations show that the resulting aminyl radical can abstract an oxygen atom from a neighboring nitramine molecule, producing an aminoxyl (nitroxyl) radical and a nitrosamine. This O-transfer reaction is exothermic by about 50 kJ/mol [B3LYP/6-31G(d); estimated standard uncertainty = 22 kJ/mol for enthalpy changes]. Nitrosamines had previously been thought to result only from radical recombination. The aminoxyl radical derived from RDX can lead easily to the OST product (s-triazine N-oxide) observed mass spectrometrically by Behrens and coworkers. The formation of persistent aminoxyl radicals is consistent with autocatalytic red oils reported in the early literature.
Proceedings of 55th JANNAF Propulsion Meeting
May 12-16, 2008
Aminoxyl, decomposition, nitramine, nitroxyl, quantum chemistry, RDX, reaction mechanism