The initial reaction mechanism of FOX-7 under high temperature and high pressure

ABSTRACTIn recent years, FOX-7 has attracted great interest due to its excellent performance. The initial decomposition mechanism of FOX-7 (ε phase) at high temperature and pressure is simulated by ab initio molecular dynamics. We mainly studied the initial reaction of FOX-7 under extreme conditions of 10 GPa and 700-3000 K. When the pressure is constant, FOX-7 shows different decomposition mechanisms as the temperature increases. At lower temperatures, hydrogen is transferred first. As the temperature increases, the transfer of hydrogen and the breakage of the C-NO2 bond leading to the generation of acid are the main initial decomposition pathways. The energy barrier for hydrogen transfer is lower than that of C-NO2 bond breaking, which was confirmed by a single-molecule transition state search. Thus, the correctness of the decomposition mechanism obtained by molecular dynamics is proved. Different from previous studies, this paper considers both temperature and higher pressure, providing a reference for the initial reaction mechanism of FOX-7 under extreme conditions.KEYWORDS: Ab initio molecular dynamicsFOX-7initial decomposition mechanism AcknowledgmentsThis work was supported by the National Natural Science Foundation of China (Grant No. 12072299).Disclosure statementNo potential conflict of interest was reported by the author(s).Data availability statementThe data that support the findings of this study are available from the corresponding author upon reasonable request and available within the article.Additional informationFundingThe work was supported by the National Natural Science Foundation of China [12072299].