K(FOX-7)·H_2O的合成、晶体结构和热行为

利用1,1-二氨基-2,2-二硝基乙烯(FOX-7)和KOH在甲醇水体系中合成了一种新型有机钾盐,并培养出K(FOX-7)·H2O单晶.该晶体属三斜晶系,P1空间群,晶胞参数:a=0.7493(2)nm,b=0.9767(3)nm,c=2.0035(5)nm,α=90.017(4)°,β=97.129(4)°,γ=90.019(4)°,V=1.4548(7)nm3,Dc=1.865g/cm3,μ=0.724mm-1,F(000)=832,Z=8,R1=0.0523,wR2=0.1082.K(FOX-7)·H2O的热分解行为可分为一个脱水和两个放热分解过程,且第一放热分解反应的表观活化能和指前因子分别为135.9kJ/mol和1012.17s-1.热爆炸的临界温度为212.02℃.同时,利用微量热法测定了K(FOX-7)·H2O的比热容,298.15K时的摩尔热容为210.88J·mol-1·K-1.用测得的比热容方程计算了298.15K为基础的FOX-7的热力学函数,并得到了绝热至爆时间为15.7～16.8s之间的某一值.

Preparation, Crystal Structure and Thermal Behavior of K(FOX-7)·H2O

A high-energy organic potassium salt of 1,1-diamino-2,2-dinitroethlyene(FOX-7) was synthesized by mixing FOX-7 and KOH in water-methanol system. Crystal structure of K(FOX-7)·H2O was determined by X-ray diffraction analysis. The crystal belongs to triclinic crystallographic system, space group P1 and cell parameters: a=0.7493(2) nm, b=0.9767(3) nm, c=2.0035(5) nm, α=90.017(4)°, β=97.129(4)°, γ=90.019(4)°, V=1.4548(7) nm3, Dc=1.865 g/cm3, μ=0.724 mm-1, F(000)=832, Z=8, R1=0.0523, wR2=0.1082. The thermal behavior of K(FOX-7)·H2O was studied, and the apparent activation energy and pre-exponential factor of the second decomposition reaction are 135.9 kJ·mol-1 and 1012.17s-1, respectively. The critical temperature of thermal explosion is 212.02 ℃. The specific heat capacity of K(FOX-7)·H2O was determined with micro-DSC method, and the molar heat capacity is 210.88 J·mol-1·K-1 at 298.15 K. Thermodynamic functions of K(FOX-7)·H2O, relative to the standard temperature 298.15K, were calculated through thermodynamic relationship, and the adiabatic time-to-explosion also was obtained as a certain value between 15.7—16.8 s.