| Furazan is a sort of compound with excellent stability.There is an oxygen atom in furazan's structure which is able to improve the oxygen balance of energetic compounds.What's more,there are also two modifiable spots in furazan's structure.These two reactive spots can be modified with various functional groups to synthesize various compounds with diversified properties to meet many kinds of requirements in practical usage.Therefore,furazan has a promising usage as gas agent.A series of research based furazan has been done in this paper.1)On the basis of density functional theory,on the level of B3LYP/6-311++g**,the geometric structures of 3-amino-4-cyano-furazan,3-amino-4-(3H-tetrazole-5-yl)-furazan and 3-nitro-4-(3H-tetrazole-5-yl)-furazan were optimized.The electronic structure and molecular orbital were calculated.Population analysis and bond order analysis were performed.The stability of three compounds was evaluated and the decomposition mechanism was predicted.Standard molar enthalpies of formation of three compounds were computed via the method of atomization energy.The detonation parameters were predicted by K-J semi-empirical equation.Among the three compounds,3-nitro-4-(3H-tetrazole-5-yl)-furazan has the most ideal properties which are high enthalpy of formation(256.32 kJ mol-1),good oxygen balance(-30.60%),high detonation velocity(7838.17 m/s)and pressure(27.32 GPa).2)On the level of B3LYP/6-311++g**,the synthesis mechanisms of 3-amino-4-(3H-tetrazole-5-yl)-furazan and 3-nitro-4-(3H-tetrazole-5-yl)-furazan are investigated via traditional transition state theory.The optimal synthesis path was confirmed according to the minimum energy principle.On the level of MP2/cc-pVTZ,the energy of each stagnation point was corrected and the reaction velocity of key steps were calculated.During the synthesis of 3-amino-4-(3H-tetrazole-5-yl)-furazan,optimizing the reaction time and choice of catalyst is significant.Similarly,controlling the reaction to be at the proper temperature and choosing the efficient nitration reagent are the vital factors of improving the productivity of synthesizing 3-nitro-4-(3H-tetrazole-5-yl)-furazan.3)On the level of GGA-PBE/DNP,the periodic structure of 3-nitro-4-(3H-tetrazole-5-yl)-furazan was optimized.For 3-nitro-4-(3H-tetrazole-5-yl)-furazan,the charge population,band structure and DOS were analyzed and the thermal kinetic parameters were calculated.The stability of 3-nitro-4-(3H-tetrazole-5-yl)-furazan was predicted theoretically,as well as the decomposition mechanism.4)Under the guidance of theoretical research,the synthesis of 3-nitro-4-(3H-tetrazole-5-yl)-furazan was optimized reasonably to improve the productivity.For the first time,the single crystal of 3-nitro-4-(3H-tetrazole-5-yl)-furazan was cultivated and reported.Besides,two energetic ion salts based on 3-nitro-4-(3H-tetrazole-5-yl)-furazan,rubidium 3-nitro-4-(3H-tetrazole-5-yl)-furazan and caesium 3-nitro-4-(3H-tetrazole-5-yl)-furazan were prepared.Crystal structures of both two salts were reported.IR,NMR,element analysis and XRPD were employed for further characterization of 3-nitro-4-(3H-tetrazole-5-yl)-furazan.Additionally,TG-DSC was used to investigate the thermal stability of 3-nitro-4-(3H-tetrazole-5-yl)-furazan and its two ion salts.Finally,the sensitivity of 3-nitro-4-(3H-tetrazole-5-yl)-furazan and its two ion salts was also studied.3-Nitro-4-(3H-tetrazole-5-yl)-furazan and its ion salts are all energetic compounds with high energy density.Both 3-nitro-4-(3H-tetrazole-5-yl)-furazan and rubidium 3-nitro-4-(3H-tetrazole-5-yl)-furazan are capable to release the energy intensively,which means both two compounds have potential application values as gas agents. |
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