Study On The Synthesis And Performance Of Energetic Salts 3-nitro-5-nitroimino-1,2,4-oxadiazole(NOA)

In recent years, new nitrogen-rich heterocyclic energetic materials have been more focused on. Among them,1,2,5-oxadiazole furazan compounds have been received extensive research. But for its isomer 1,2,4-oxadiazole has rarely been reported. Introduce the 1,2,4-oxadiazolecan improve the thermal stabilities and impact sensitivities. The energetic salts of 1,2,4-oxadiazole tend to exhibit lower vapor pressures and higher thermal stability, and through design of the anionic and cationic to obtain energetic salts with excellent comprehensive performance.First, we by the oxidation reaction of 3,5-diamino-1,2,4-oxadiazole(DAO) to synthesis the key intermediates NOA. A variety of oxidation method were EXPLOd, eventually found in H2O2/Na2WO4/β-cyclodextrin/H2SO4 as oxidation conditions, the use amount of H2O2, Na2WO4,- H2SO4 was studied, and the strength of the acid and the influence of temperature on the yield, finally found, at room temperature, the amount of sulfuric acid is 1 mL, hydrogen peroxide is 10 mL, Na2WO4 is 1 equiv yield was the highest up to 23%.Then the oxidation reaction of NOA by sodium dichloro-isocyanurate(SDCI), DNOA-Na and DNOT-Na was obtained. The yield is 36% and 56%. They were fully characterized by 13C-NMR spectroscop.N-Nitration of NOA to obtain silver salt and sodium salt of 3-nitro-5-nitroimino-1,2,4-oxadiazole(NON). Next, a series of 3-nitro-5-nitroimino-1,2,4-oxadiazole-based energetic salts were prepared. They were fully characterized by IR, NMR spectroscop and elemental analysis, among of salts, the triaminoguanidinium salt was confirmed by single crystal X-ray diffraction. With respect to performance, all salts showed good thermal stability with decomposed temperature ranging from 155 oC to 258 oC. Positive heats of formation from 226.0 k J/mol to 554.1 kJ/mol. In terms of detonation performance, detonation performances were predicted using the EXPLO 5.0 program, the detonation pressure was predicted from 28.70 GPa to 37.60 Gpa. In terms of detonation velocitiy, the values of guanidinium salt(9319 m/s) and triaminoguanidinium salt(9354 m/s), they have good detonation velocitiy.