Study on the Reaction Mechanism and Kinetics of the Thermal Decomposition of Nitroethane

Despite many theoretical and experimental advances in understanding the macroscopic properties of energetic materials, much work remains to be done to understand their microscale mechanism. In this work, the reaction mechanism and kinetics of thermal decomposition of nitroethane were studied by density functional theory (DFT) calculations, automatic pressure tracking adiabatic calorimeter (APTAC) measurements, and gas chromatography (GC) analysis. The APTAC results were used to determine Arrhenius parameters of A = 1013.5±0.2 and Ea = 46.2 ± 0.5 kcal/mol. The decomposition process includes three initial steps: concerted molecular elimination of HONO, nitro−nitrite isomerization, and rupture of C−NO2. Followed these initial reactions, a detailed mechanism that consists of 23 elementary steps was proposed. Numerical simulations of the proposed mechanism reproduce reasonably well the distributions of major products over the temperature range. It was found that the relative concentrations of NO and C2H4 depend on the reaction temperatures. Combining theoretical and experimental studies, it is concluded that elimination of HONO is predominant at low temperature and dissociation of C−NO2 becomes significant at high temperature.