Thermal decomposition of hydroxylamine nitrate studied by differential scanning calorimetry analysis and density functional theory calculations

The thermal stability and kinetics of hydroxylamine nitrate (HAN) decomposition were studied by differential scanning calorimetry (DSC) and the thermal decomposition reaction mechanism was determined by density functional theory (DFT). With the help of parameter values from the non-isothermal DSC curves of HAN, the thermal decomposition activation energy and pre-exponential constant were obtained by the Kissinger and Ozawa methods. Then, the most probable mechanism function was calculated by the Satava-Sestak method. Seven different paths for the thermal decomposition mechanism of HAN were formulated and DFT at the B3LYP/6-311++G(d, p) level was used to carry out the dynamics analysis. The calculated results show that the values of the activation energy calculated by the Kissinger and Ozawa methods are 67.892 and 70.412 kJ mol(-1) respectively. The most probable mechanism function calculated by the Satava-Sestak method is F(alpha) = (1-alpha)(-1/17). The path being favoured energetically in the dynamics is in the order: Path6 > Path5 > Path4 > Path1 > Path2 > Path7 > Path3.