1-甲基-4,5-二硝基咪唑的晶体结构与热分解特性

以1-甲基咪唑为原料,通过硝化合成了1-甲基-4,5-二硝基咪唑.以乙腈为溶剂培养得到了1-甲基-4,5-二硝基咪唑单晶,用X射线单晶衍射仪测定了晶体结构.结果表明:晶体属斜方晶系,空间群为P na21.晶体学参数为:a=0.841 2(2)nm,b=1.264 6(3)nm,c=0.656 3(1)nm,V=0.698 2(3)nm3,Z=4,Dc=1.637 g.cm-3,μ=0.147mm-1,F(000)=352.用DSC研究了热分解过程,结果表明:1-甲基-4,5-二硝基咪唑的分解由一个吸热和一个放热过程组成,吸热峰由晶体熔融转变引起,放热峰由热分解所致;较高的分解温度表明1-甲基-4,5-二硝基咪唑有较好的热稳定性.

Crystal Structure and Thermal Decomposition of 1-Methyl-4,5-Dinitroimidazole

1-methyl-4,5-dinitroimidazole was synthesized with 1-methylimidazole as primary substance by nitration.The single crystal of 1-methyl-4,5-dinitroimidazole was cultivated from acetonitrile.Its crystal structure was determined by X-ray single crystal diffractometer.The results show that the crystal is belong to orthorhombic system,space group P na21,with crystal parameters of a=0.841 2(2) nm,b=1.264 6(3) nm,c=0.656 3(1) nm,V=0.698 2(3) nm3,Z=4,Dc=1.637 g·cm-3,μ=0.147 mm-1,F(000)=352.Its thermal decomposition mechanism was studied by DSC.The thermal decomposition of 1-methyl-4,5-dinitroimidazole consists of one endothermic and one exothermic decomposition processes continuously.The endothermic peak is attributed to the crystal transformation and the exothermic peaks are due to the decomposition reaction of 1-methyl-4,5-dinitroimidazole.Higher decomposition temperature shows that 1-methyl-4,5-dinitroimidazole has better thermal stability.