Thermochemical and Energy Characteristics Di-, Tri-, and Tetra-Azido-Substituted Azines As Gasifying Agents of Solid Fuels for Ramjet Engines

Abstract

A number of di-, tri-, and tetraazido-substituted azines as potential energetic dispersing agents of solid propellants for ramjet engines have been studied. The enthalpy of combustion and the enthalpy of formation of several azides (2,4,6-triazidopyrimidine, 2,4,6-triazidopyridine, 3,4,5-triazidopyridine-2,6-dicarbonitrile, and 3,4,5,6-tetraazidopyridine-2-carbonitrile) were experimentally determined. Eleven azides were compared with HMX in terms of the enthalpy of combustion in oxygen to CO₂ and water (in the case of the presence of hydrogen in the component), as well as in terms of the temperature of the products of adiabatic conversion of the investigated components due to the high enthalpy of formation in the absence of an external oxidizer and the amount of gases released in this process. The enthalpy of combustion of all the investigated azides burned in air was found to be significantly higher than that of HMX, and for seven of the azides studied, the combustion temperature is significantly higher. As regards the gas release volume (24–31 mol/kg), the azides are inferior to HMX (41.9 mol/kg). Based on the combination of properties, the investigated azides can be considered as promising dispersing agents of solid propellants for ramjet engines.