New Energy-insensitive Materials Fox-7 Synthesis, Structure And Nature Of The Study

As the energy source of military weapons and active working medium, the energetic material has been widely considered as a basic industry and a crucial field for the national defense industry as well as the whole national economy. However, how to compromise the contradiction between "high energy" and "high safe" of enegetic materials and obtain a new generation of insensitive high explosives(IHE) is a hot topic for experts all over the world. Under this background, a new explosive 1,1-diamino-2,2-dinitroethylene(FOX-7) was developed. Its stable molecular structure, excellent all-over properties and wild prospect for application received much attention from relevant researchers.Targeted at exploiting the superior performance of FOX-7 and searching for more ideal novel energetic materials, six kinds of salts and derivatives of FOX-7 were synthesized, their single crystals were firstly obtained and the structure were determined by four-circle X-ray diffractometer.The six new compounds are: Guanidinium salt of FOX-7---G(FOX-7) 1-Amino-1-hydrazino-2,2-dinitroethene---AHDNE 1-Amino-1-methylamino-2,2-dinitroethlyene---AMFOX-7 2-(1,1-Dinitromethylene)-l,3-diazepentane---DNDZ Potassium salt of FOX-7---K(FOX-7)·H₂O Potassium salt of DNDZ---K(DNDZ).Gaussian 03 package was used to optimize structure geometry and compute frequencies of the compounds. The optimized parameters, natural atomic charges, frontier orbital energy and main atomic orbital percentage were provided.The thermal behaviors of the above six compounds were studied under non-isothermal conditions by DSC and TG/DTG methods. The Kissinger method, Ozawa method, differential method and integral method were employed to determine kinetic parameters and thermal decomposition mechanism functions of ANDNE,AMFOX-7 and K(DNDZ) in exothermic processes. The entropy of activation (△S^≠) enthalpy of activation (△H^≠),Gibbs free energy of activation (△G^≠) and critical temperature of thermal explosion (T_b) of the six compounds were obtained.The continuous specific heat capacity of FOX-7 and other six new compounds were determined. Based on the C_p results , the thermodynamic values (enthalpy, entropy and Gibbs free energy) of compounds between 283-353 K, relative to the standard temperature 298.15 K, were derived through thermodynamic equations. Meanwhile, using C_p functions and thermal decomposition parameters, the adiabatic time-to-explosion of FOX-7, AHDNE, AMFOX-7, DNDZ and K(DNDZ) were estimated, as an important parameter, which can be used to estimate thermal stability and safety of engetic materials directly.