On the nature of the burning rate-controlling reaction of energetic materials for the gas-phase model

For model systems with known kinetics of elementary reactions (CH$_3$NO$_2$ and HN$_3$), temperature ranges are established in which the rate-controlling reactions are the initial endothermic decomposition of the starting material or the subsequent secondary reactions. Heat release in reactions of NO$_2$, NO, and N$_2$O with various fuels, such as CH$_2$O, CO, H$_2$, and HCN, is modeled to establish the kinetic parameters and nature of the rate-controlling reactions in gas flames of nitro compounds. It is shown that the activation energy of the heat-release reaction due to the interaction of NO$_2$ with a hydrocarbon fuel (which is characteristic of the first flame of nitro compounds) is in the range of 29–33 kcal/mole, depending on the type of fuel. According to the calculations performed, the activation energy of the rate-controlling heat-releasing process due to the deoxidation of NO and N$_2$O (which is typical of the second flame of nitro compounds) is 43–58 kcal/mole. In the range of high pressures, where the flames merge, the kinetic parameters of heat release are determined by the reactions of the most reactive nitrogen oxide NO$_2$.