Abstract
Simulated ageing of 2,4-dinitro-1-ethylbenzene (DNEB) in DMSO in the presence of O2 in a closed system at 85–105°C gave benzylic oxidised products 1-(2,4-dinitrophenyl)ethanol (DNPE) and 2,4-dinitroacetophenone (DNAP), with the latter as the major product. Evidence for the formation of 3-methyl-6-nitro-2,1-benzoisoxazole (an ‘anthranil’), suggested in the literature as a likely decomposition product, is scant. A mechanism with initial H-abstraction to yield an electron-rich benzylic radical as the rate-limiting step is suggested, supported by a small kinetic isotope effect kH/kD ~2 and a reactivity in the order 2,4,6-trinitro-1-ethylbenzene TNEB > DNEB > 4-nitro-1-ethylbenzene (NEB). The activation energy for DNEB oxidation is 40 kJ mol−1, a value that translates to 1% oxidative decomposition of DNEB after ~ 14 d under an O2 atmosphere, or 70 d in air at ambient temperature.