The Thermal Decomposition of Hydrazod carbonamide

Abstract

The thermal decomposition of hydrazodicarbonamide in solid state has been studied. Thermal characteristics were examined by DTA and TG. The decomposition products were identified and estimated by pyrolysis gas chromatography, infrared and mass spectrometries. The decomposition proceeds initially in the solid phase and then in melts as the products increase during the decomposition. Overall reaction was endothermic. Main products were urazole and ammonia. Among others were small amount of nitrogen, isocyanic acid, carbon monoxide, biuret, semicarbazide, urea and negligible amounts of ammonium isocyanate. The kinetics of decomposition was evaluated by the gas evolution method over the range between 238°C and 248°C. The reaction was autocatalytic and its process was expressed by Prout-Tompkins equation. The apparent activation energy and the pre-exponential factor were 40.0 kcal/mol and 3.3 X 10 sec-1, respectively. On the bases of these results, following reaction mechanism has been proposed; the production of urazole by ammonium release from substrate and the subsequent reaction involving formed radicals.