Synthesis Of Bicyco-tetrazolium Energetic Compounds

Tetrazolium compounds, especially bicyclotetrazolium compounds, become the promising high energy density materialsespecially TKX-50 (Dihydroxylammonium 5,5’-bistetrazole-1,1’-diolate). Not only do tetrazolium compounds increase the heat of formation of the compound due to inherently energetic C-N and N-N bonds contained in the molecule, it also bring the environmental benefit_of releasing mainly N2 after decomposition, high density, high thermal stability, and low sensitivities.A novel high nitrogen energetic compound 5-((5-nitro-2H-tetrazol-2-yl)methyl)-1H-tetrazol-1-ol was synthesized with a total yield of 19% via diazotization-nitration, alkylation, oximation, diazotization-chlorination, azidation and cyclization using 5-aminotetrazole as starting material. It was characterized by NMR, MS, IR and elemental analysis. The crystal structure of this compound was determined by X-ray single crystal diffraction analysis. The thermal properties were studied by DSC and TG analyses. The detonation velocity and detonation pressure of this compound calculated by Kamlet-Jacobs formula ware 8500 m·s-1 and 31.53 GPa respectively. And then, the energetic salts of 5-((5-nitro-2H-tetrazol-2-yl)methyl)-1H-tetrazol-l-ol such as ammonium salt, hydroxyammonium salt, guanidinium salt, aminoguanidinium salt, diaminoguanidinium salt, 1-amino-3-nitroguanidinium salt was synthesized via the reactions of substitution or neutralization. Those salts ware characterized by NMR, IR, DSC, TG and elemental analysis.The detonation velocity and detonation pressure of those salts were calculated by Kamlet-Jacobs. The crystal structure of ammonium salt was determined by X-ray single crystal diffraction analysis.TKX-50was synthesized via the reactions of oximation, chloration, azidation, cyclization and neutralization using glyoxal as starting material. The systhsis condition of an important intermediate 5,5’-Bistetrazole-I,I’-diol dihydrate was optimized. It was directly synthesized from dichloroglyoxime. The effect of solvent, temperature and reaction time were investigated. Results showed that the optimal reaction conditions of the reaction were determined as:mixed solvent of acetone-water at 0℃ for 1.5 h and then extracted by diethyl ether for cyclization with hydrogen chloride gas, at last, the yield of this whole reaction could be up to 88%. In the preparation process of TKX-50 from 5,5’-Bistetrazole-l,l’-diol dehydrate, the influence of reaction time, solvent and temperature on the yield of TKX-50 were studied. The optimal conditions of this process were determined:when the reaction was operated in acetic ether at 50℃ for 2 h, the yield could reached to 94%.A series of bicyclotetrazolium compounds was synthesized and characterized to meet the demands of high energy density materials.