Synthesis And Performance Research Of The Energetic Compounds Of N-trinitromethyl-substituted Azoles

The goal of energetic materials at home and abroad is high energy density and low(blunt)sensitivity.However,high energy and insensitivity is a contradiction for energetic materials themselves.The pursuit of minimization is always a hot topic in the field of energetic materials.Nitroazole compounds have received extensive attention due to their good detonation properties,low sensitivity and good molecular stability.This paper mainly includes the construction of the new N-Trinitromethyl-Substituted azoles compounds,explore the synthesis methods and characterization of molecular and crystal structure,stability and safety of the molecules,and the formation of different nitrification conditions trinitromethyl groups are studied.Using 3-nitro-1,2,4-triazole as starting materials,N-trinitromethyl-3-nitro-1,2,4-tria-zole(TNMNT)was synthesized via substitute on reaction.nitration with total yield of 62%.The single crystal of TNMNT was first cultured by solvent evaporation method using ethanol as solvent.And its structure was characterized by NMR,IR,and single crystal X-ray diffraction analysis.The thermal stability was analyzed by the DSC-TG method,the enthalpy of formation and detonation parameters was calculated theoretically with Gaussian 09 and EXPLO5(V6.02)program respectively.Results show that the crystal of TNMNT belongs to monoclinic system,space group P21/c,a=6.643(3)A,b=20.494(7)A,c=6.698(3)A,? = 94.225(9)°,V=909.4(6)A,Z=4,dc = 1.922 g·cm-3,?=0.190 mm-1,F(000)=528.0.The peak decomposition temperature of TNMNT is 158.3 ?.The enthalpy of formation is 210.9 kJ·mol-1,the detonation velocity is 9023 m·s-1,and the detonation pressure is 35.5 GPa.The existence of numerous intermolecular and intramolecular hydr ogen bonds makes the TNMNT molecule structurally stable,and the energy of TNMNT is also enhanced with the introduction of the trinitromethyl moeity.By the synthesis of TNMNT,the synthesis conditions of N-Trinitromethyl-Substituted azoles compounds were preliminarily explored.N-trinitromethyl-4,5-dicyano-2-H-1,2,3-triazole was readily synthesized from 4,5-dicyano-2H-1,2,3-triazole.Its crystal structure was obtained for the first time and its crystalline density in 296 K was 1.729 g·cm-3.It shows high nitrogen and oxygen content up to 77.6%,high calculated solid heat of formation(564 kJ·mol-1),and superior detonation pressure and detonation velocity(D=8619 m·s-1,P=30.8 GPa).This new hydrogen-absent explosive shows high impact and friction sensitivities(IS:1.25 J,FS:32 N),which is lower than commercial primary explosive 2-diazonium-4,6-dinitrophenol(DDNP)(IS:1 J,FS:5 N).The relationship between intermolecular-interaction and sensitivity as well as thermal stability of the title compound was investigated by Hirshfeld surface analysis and fingerprint plot.Its thermodynamic properties was studied by non-isothermal kinetic methods based on the results of differential scanning calorimeter(DSC).It is interesting that apparent activation energy(Ea)at Tp1(210.89-214.17 kJ·mol-1)is higher than those at Tp2(133.90-134.87 kJ-mol-1).In addition,gaseous product of this new energetic compound was analyzed by the rapid scanning Fourier transform infrared spectroscopy(RS-FTIR)from 20 ? to 200 ? and its detonation products was theoretically predicted.Based on the decomposition products,its decomposition mechanism was discussed under inert atmosphere.It is undoubted that these significant physicochemical properties make N-trinitromethyl-4,5-dicyano-2H-1,2,3-triazole an interesting and unique hydro gen-absent explosive worthy of further investigation.Novel nitrogen-rich ionic salt of bis(aminoguanidium)-bis-(5-nitroimino-1,2,4-triazolate-3-yl)methane((AG)2BNTM)was synthesized for the first time and its crystalstructure was then determined by X-ray diffraction.Along with the crystal structures and optimization of geometric structures,we employ the Hirshfeld surface analysis to analyze the types of interactions and relative energetic contributions of the weak intermolecular-interaction.Thermal stability was studied by DSC-TGA technique.The N post of nitroimidazole ring lead into trinitromethyl groups was studied,and N-trinitromethyl-2-nitroimidazole and N-trinit-romethyl-4-nitroimidazole was successful synthesis.By nitration precursor compounds N-acetonyl-substituted-nitroimidazoles using different concentration of sufur nitrate mixed system,we obtaine a series of new and application compounds.It lays the foundation for the continued research of this subject.