Synthesis and Thermal Properties of Three Energetic Ion Salts of 3,6-Bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine

Three energetic ion salts of 3,6-bis[(1H-1,2,3,4-tetrazol-5-yl)-amino]-1,2,4,5-tetrazine(BTATz), namely, methylamine salt(compound 1), ethylenediamine salt(compound 2), and diethylamine salt(compound 3), were synthesized and characterized by elemental analysis, Fourier transform infrared spectrometry, H-1 NMR spectroscopy, and C-13 NMR spectroscopy. The crystal structure of compound 1 was determined by single-crystal X-ray crystallography, and structural analysis revealed that it belonged to the monoclinic system with P2(1)/c space group. In addition, the thermal behavior of the three compounds was studied by differential scanning calorimetry and thermogravimetry techniques. The thermal decomposition peak temperatures of the compounds were 574.89, 545.60, and 606.72 K, indicating that the three ion salts exhibited good thermal stability. The kinetic mechanism equations of the main decomposition process and the entropy of activation(Delta S-not equal), enthalpy of activation(Delta H-not equal), and Gibbs free energy of activation(Delta G(not equal)) of the three compounds were also obtained. Moreover, the thermal safety of the compounds was evaluated by the values of the self-accelerated decomposition temperature(T-SADT), thermal ignition temperature(T-TIT), and critical temperature of thermal explosion(T-b). The results showed that all the compounds demonstrated good thermal safety, and the thermal safety of compound 3 was better than that of the others.