2,6-二氨基-3,5-二硝基-1-氧吡嗪的热分解动力学研究

在升温速率分别为5 K·min~(-1)、10 K·min~(-1)、20K·min~(-1)条件下,用DSC 研究了2,6-二氨基-3,5-二硝基-1-氧吡嗪(LLM-105)的热分解反应动力学参数,并在此基础上考察了该炸药的热爆炸临界温度和500d自爆温度;确定了该反应的微分形式的动力学模式函数f(_α)、表观活化能(E_a)、指前因子(A)、热分解动力学方程和120℃时的分解速率常数k.研究表明,反应的活化熵(ΔS~≠)、活化焓(ΔH~≠) 和活化自由能(ΔG~≠)分别为176.05J·mol~(-1)·K~(-1)、305.60kJ·mol~(-1)和198.22kJ·mol~(-1);LLM-105炸药的热爆炸临界温度和500d自爆温度分别为347.26℃和239.42℃.

Study on Thermal Decomposition Kinetics of 2,6-diamino-3,5-dinitropyrazine-1-oxide

At heating rates of 5 K·min~(-1),10 K·min~(-1) and 20K·min~(-1) respectively,the thermal behavior,mechanism and kinetic parameters of the exothermic decomposition reaction of 2,6-diamino-3,５-dinitropyrazine - 1- oxide (LLM-105) were investigated by the mean of DSC. On this basis,the critical temperature of thermal explosion and 500 day cookoff temperature were also calculated and studied. Results show that kinetic model functions in differential forms f(α),the apparent activation energy (E_α),the pre-exponential factor (A),thermal decomposition kinetic equation and decomposition rate constant at 120℃ of LLM-105 are 2(1-d)~2,05.60kJ·mol~(-1),1.995×10~(22)s~(-1),dα/dt=3.99×10~(22)×(1-α)~(1/2)exp(-3.676×10~4/T) and 4.95×10~(-19)s~(-1), respectively. The values of ΔS~≠,ΔH~≠ and ΔG~≠ of the reaction at 336.79℃ are 176.05J·mol~(-1)·K~(-1),305.60kJ·mol~(-1),198.22kJ·mol~(-1),respectively. The critical temperature of thermal explosion and 500 day cookoff temperature for this explosive are 347.26 ℃ and 239.42℃,respectively.