Synthesis and thermal decomposition performance of 3,6,7-triamino-7H-s-triazolo[5,1-c]-s-triazole

Abstract

3,6,7-Triamino-7H-s-triazolo[5,1-c]-s-triazole was synthesized from triaminoguanidine hydrochloride and cyanogen bromide, and has been prepared at the 30-g scale. A single crystal of 3,6,7-triamino-7H-s-triazolo[5,1-c]-s-triazole was cultivated, and its crystalline density at 293 K was 1.726 g cm−3. Its heat of formation (ΔH f,solid = 470.5 kJ mol−1) was computed by using the density functional theory (DFT) method, and its detonation pressure and detonation velocity were further predicted by EXPLO5 code (D = 9483 m s−1, P = 30.4 GPa). The intermolecular interaction of the title compound was investigated by Hirshfeld surface analysis. Moreover, its thermodynamic performance was evaluated by non-isothermal kinetic methods based on the results of the differential scanning calorimeter (DSC), which shows that the apparent activation energy (E a) obtained by Kissinger, Ozawa and Starink methods is 223.55, 221.61 and 223.73 kJ mol−1, respectively. Meanwhile, the transformation of molecular structure was analyzed by the rapid scanning Fourier transform infrared spectroscopy (RSFT-IR) under the temperature range from 50 to 300 °C. The reaction pathway was further supported by quantum chemical calculations. 3,6,7-Triamino-7H-s-triazolo[5,1-c]-s-triazole processes good vacuum thermal stability, high detonation performance and low sensitivity. It is convincible that these physical–chemical properties make 3,6,7-triamino-7H-s-triazolo[5,1-c]-s-triazole a promising candidate worthy of further investigation.