The role of regioisomerism on thermal stability of furoxan based energetic materials

Abstract

Development of high-performance energetic materials with good stabilities has been a great challenge, since such materials essentially suffer from high sensitivities. Regioisomerism, as an effective modification strategy for molecular properties, presents impacts on thermal stabilities of energetic materials. In this study, the effects of regioisomerism on thermal stabilities of a pair of furoxan based energetic materials (M3 and M4) have been thoroughly investigated. The initial decomposition mechanisms of the regioisomers are fully discussed, the NO2-dissociation path is proved as the primary decomposition path, instead of the previously reported ring-open channel. An unusual transition state is found for the NO2-dissociation path, due to the existence of Van der Waals potential well, which attributes to the strong weak interaction between the dissociation products. The regioisomerism has impacts on both molecular structures and decomposition mechanisms of M3 and M4. The existence of intramolecular weak interactions and the electron effects contribute to the molecular stability of M4. The elevation in the energy barrier of initial decomposition path of M4, and the decline in the energy of dissociation products of M3, result in different thermal stabilities of M3 and M4.