Kinetics of the thermal decomposition of dinitramide - 3. Kinetics of the heat release during the thermal decomposition of dinitramide ammonium salt in the liquid phase

The kinetic regularities of the heat release during the thermal decomposition of liquid NH4N(NO2)(2) at 102.4-138.9 degrees C were studied. Kinetic data for decomposition of different forms of dinitramide and the influence of water on the rate of decomposition of NH4N(NO2)(2) show that the contributions of the decomposition of N(NO2)(2)(-) and HN(NO2)(2) to the initial decomposition rate of the reaction at temperatures about 100 degrees C are approximately equal. The decomposition has an autocatalytic character. The analysis of the effect of additives of HNO3 solutions and the dependence of the autocatalytic reaction rate constant on the gas volume in the system shows that the self-acceleration is due to an increase in the acidity of the NH4N(NO2)(2) melt owing to the accumulation of HNO3 and the corresponding increase in the contribution of the HN(NO2)(2) decomposition to the overall rate. The self-acceleration ceases due to the accumulation of NO3- ions decreasing the equilibrium concentration of HN(NO2)(2) in the melt.