Studies on Thermodynamic Properties of FOX-7 and Its Five Closed-Loop Derivatives

Combustion heats of FOX-7 and its five closed-loop derivatives were determined and the standard molar enthalpies of formation (Delta H-f(m)o) were obtained. The sequence of combustion heat for the six compounds is DNDH > MDNZ > DNDX > DNDZ > DDNI > FOX-7. Combustion heat tends to rise with the increase of the number of C atoms in the molecule. Specific heat capacities were measured, and the standard molar heat capacities of the six compounds are (176.59, 205.41, 207.76, 218.89, 217.76, and 215.40) J.mol(-1).K-1, respectively. The specific heat capacity presents an opposite change rule with combustion heat. To the isomers and the introduction of hydroxyl group, the change rule is the same. Moreover, the introduction of hydroxyl group can markedly decrease the combustion heat and specific heat capacity.