Thermochemical and energy characteristics of alcoxy-NNO-azoxy derivatives of pyrazoles and nitropyrazoles

The standard enthalpies of formation of the compounds 1-(2,2-bis(methoxy-NNO-azoxy)ethyl)pyrazole, 1-(2,2-bis(methoxy-NNO-azoxy)ethyl)-3-nitropyrazole, and 1-(2,2-bis(methoxy-NNO-azoxy)ethyl)-4-nitropyrazole were measured experimentally to be 273.6 $\pm$ 6.7, 231.0 $\pm$ 3.3 and 213.8 $\pm$ 7.9 kJ/mol, respectively. These enthalpy values were used to determine the contribution of the replacement of H atoms at N atoms in heterocycles by CH$_2$CH(N$_2$O$_2$Me)$_2$ groups (151.9 kJ/mol). Calculations have shown that compared to HMX, 1-(2,2-bis(methoxy-NNO-azoxy)ethyl derivatives of pyrazole, 3- and 4-nitropyrazole, 3,4-diniteopyrazole, 3,4,5-ttrinitropyrazole, the bis-derivative bis-furazano[3,4-b;3',4'-e] piperazine are worse gasifying components of solid composite propellants in metal-free compositions with an active binder. Only the derivative 3,4-dinitropyrazole, which at low content and combined with ammonium perchlorate provides a specific impulse of 249 s in aluminum-free propellant compositions.