Kinetic Characteristics of Urotropine Gasification in Nitrogen and Carbon Dioxide Flows

Based on the data of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), the kinetic characteristics of the thermal decomposition of urotropine in flows of N2 and CO2 are determined. The sample heating rates are 20, 60, and 90 K/min. The values of the kinetic rate constants of the decomposition of urotropine are determined by the Kissinger method. During gasification in nitrogen, the activation energy of the thermal decomposition of urotropine increases from 106 to 139 kJ/mol under conditions of an increase in the degree of conversion of the substance. The preexponential value also increases from 0.35 × 109 up to 145 × 109 s–1. The decomposition of urotropine proceeds by an exothermic reaction with a heat of 368, 339, and 275 kJ/kg for heating rates of 20, 60, and 90 K/min, respectively. During gasification in carbon dioxide, the activation energy of the thermal decomposition of urotropine first increases from 110 to 132 kJ/mol as the degree of conversion increases, and then decreases to 120 kJ/mol. The heat of decomposition of urotropine in a flow of CO2 is 382, 327, and 303 kJ/kg for heating rates of 20, 60, and 90 K/min, respectively.