Kinetics analysis of thermal decomposition of ammonium dinitramide (ADN)

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 NH 3 , H 2 O, N 2 , NO, N 2 O, and NO 2 . 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 N 2 has the same value as that of evolving H 2 O since they occur by the same mechanism. A Friedman plot obtained from the DTA data has a curve similar to those obtained from N 2 and H 2 O. The reaction that generated N 2 and H 2 O plays an important role in the exothermic reaction in the decomposition of ADN. The activation energy for the N 2 O 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 .