Kinetics analysis of thermal decomposition of ammonium dinitramide (ADN)

Abstract

Kinetics analyses were performed on the thermal decomposition of ammonium dinitramide (ADN) using thermogravimetry-differential thermal analysis–mass spectrometry–infrared spectroscopy (TG-DTA–MS–IR). The main evolved gases were determined to be NH3, H2O, N2, NO, N2O, and NO2. The apparent activation energies of the exothermic, mass-change and gas-evolving reactions were analyzed on the basis of Friedman methods. The apparent activation energy of evolving N2 has the same value as that of evolving H2O since they occur by the same mechanism. A Friedman plot obtained from the DTA data has a curve similar to those obtained from N2 and H2O. The reaction that generated N2 and H2O plays an important role in the exothermic reaction in the decomposition of ADN. The activation energy for the N2O evolution reaction has a range of approximately 120–152 kJ mol−1 with reaction progress values between 0.1 and 0.9. Quantum chemistry calculations revealed that the total energy barrier of dinitramic acid unimolecular decomposition and ammonium-dinitramic ions collision-induced decomposition is 149.9–156.0 and 160.6 kJ mol−1, respectively. These values are reasonable compared with the experimental value of 152 kJ mol−1.