Quantum Mechanical Investigation on Decomposition Pathways of BuNENA

Abstract

The unimolecular decomposition pathways of nbutyl nitroxyethylnitramine (BuNENA) were computationally investigated. The OÀ NO 2 bond dissociation energies (BDEs) are found to be smaller than the NÀ NO 2 BDEs. The consecutive NO 2 elimination via TSA1 is more favorable kinetically than that via TSA2 although both of them form the same intermediate of n-butyl-aminoacetaldehyde (BuAAA). Isomerization of n-butyl-nitramineethyloxidanyl radical (Bu-NEȮ) formed by homolytic cleavage of OÀ NO 2 bond was found to eliminate NO 2 with a negative bond dissociation energy. Among the NO 2 elimination pathways, the formation of C 4 H 9 NCH 2 (PB2b), CH 2 O, and NO 2 from BuNEȮ via the saddle point TSB2a was found to be the most kinetically favorable with a low activation energy barrier. In contrast, the consecutive HONO elimination is the most thermodynamically favorable with a high exothermicity (À ~H0 ). The first-principle kinetic Monte Carlo (kMC) simulations show that the NO 2 elimination of BuNEȮ via TSB2a plays an important role in driving the decomposition of BuNENA.