Thermal behavior of 3-Nitro-5-guanidino-1, 2, 4-oxadiazole

3-Nitro-5-guanidino-1, 2, 4-oxadiazole (NOG) was obtained by oxidation of diaminoglycoluril (AG) with in situ generated dimethyldioxirane (DMDO). The particle morphological appearance of NOG prepared with the quick precipitation method was studied by scanning electron microscopy (SEM). The thermal behavior of NOG was studied by differential scanning calorimetry (DSC) and differential thermal/thermo-gravimetric analyzer (TG-DTA). The apparent activation energy (E) and pre-exponential factor (A) of the exothermic decomposition reaction, the peak temperature (T _P0) of heating rate β→0, and activation entropy (ΔS ^≠), activation enthalpy (ΔH ^≠), activation Gibbs free energy (ΔG ^≠) at T _P0 of the reaction and the critical temperature of thermal explosion (T _b) were calculated. The results show that NOG has better heat-resistance ability. The decomposition temperature of NOG is 290°C. The critical temperature of thermal explosion (T _b) is 291.56°C, ΔS ^≠ is 232.35 J·k ^-1·mol ^-1, ΔH ^≠ and ΔG ^≠ is 267.36 kJ·mol ^-1 and 138.42 kJ·mol ^-1, respectively.