Synthesis and Properties of 1,2,4-Triazol-3-one-Based Energetic Compounds

1,2,4-Triazol-3-one (TO) is an important nitrogen-rich heterocycle in synthesis chemistry. In the field of energetic materials, some synthesis strategies are applied to prepare TO-derived energetic materials. However, none of them can be used as a heat-resistant energetic material due to their lower decomposition temperatures. In this paper, a series of energetic TO derivatives 4-13 were prepared from 5oxo-4,5-dihydro-1H-1,2,4-triazole-3-carboxylic acid. These compounds were fully characterized by using elemental analysis, 1H and 13C NMR spectroscopy, IR analysis, and MS. The crystal structures of fused-ring compound 6 and perchlorate 8 were further identified using single-crystal X-ray diffraction. Most compounds exhibit good thermostability (Td = 166.5-324.5 degrees C), low sensitivities (impact sensitivity IS > 20 J; friction sensitivity FS > 360 N), good detonation performance (Dv = 7905-8753 m s-1), and positive heats of formation (Delta Hf = 295.9-1121.1 kJ mol-1), except compound 9 (Td = 92 degrees C; IS = 15 J; FS = 240 N). Among these target molecules, compound 6 with a high decomposition temperature (Td = 324.5 degrees C), a high density (rho = 1.859 g cm-3), low sensitivities (IS > 40 J; FS > 360 N), and a decent detonation performance (Dv = 8406 m s-1; P = 29.2 GPa) is superior to the traditional heat-resistant explosive hexanitrostilbene (Td = 318 degrees C; rho = 1.750 g cm-3; IS = 5 J; FS = 240 N; Dv = 7612 m s-1; P = 26.3 GPa) and can be used as an insensitive and thermostable energetic material.

Automated summary

1,2,4-Triazol-3-one (TO) was used as the research object in this paper. A series of TO derivatives were synthesized and characterized, showing excellent thermal stability, low sensitivity, good detonation performance, and positive heats of formation. Compound 6, with high decomposition temperature, low sensitivity, and decent detonation performance, can be used as an insensitive and thermostable energetic material.