Impact of regiochemistry on thermal stability of trifuroxan based energetic materials: A theoretical perspective

Abstract

Improving the stability of energetic materials with high energy density has been an issue over the past decades. Regioisomerism, as an effective molecular modification strategy, shows the potential to improve the thermal stability of energetic materials without a compromise in energy density. In this study, the impacts of regioisomerism on thermal stabilities of two trifuroxan based energetic regioisomers (BFTF-1 and BFTF-2) have been thoroughly investigated. The initial decomposition mechanism has been studied to reveal the decomposition process. According to the Gibbs free energy profiles, NO2-dissociation path is proved as the primary decomposition path for both regioisomers, and the difference in energy also well explains their distinct thermal stabilities. The regioisomerism impacts on molecular structure and NO2 connection have been evaluated through intramolecular interactions and electron effects. The structure of BFTF-2 has been stabilized by an intramolecular electrostatic attraction, the connection of the leaving NO2 group in BFTF-1 has been weakened by intramolecular steric effect, both of which result in different thermal stabilities of BFTF-1 and BFTF-2.