布洛芬的热行为和热分解反应动力学

Thermal behavior and decomposition kinetics of ibuprofen

目的 研究布洛芬(ibuprofen) 的热分解行为, 推导出其最可能的热分解反应机制, 并求出相关的动力学参数。方法 用TG- DTG技术研究布洛芬在空气气氛中的热分解行为, 协同使用4 种热分析动力学方程推导出其最可能的热分解反应机制, 求出相关的动力学参数。结果 布洛芬的热氧分解活化能Eα=94. 8 kJ·mol-1, lnA =18 .46 s-1; 其降解过程符合收缩圆柱体的相界反应模型函数, 动力学方程为dα/dt=Ae-Eα/RT 2 (1-α)1/2; 动力学补偿效应数学表达式为lnA=0 .251 4Eα-6 .763 7, 相关系数r=0. 999 4。结论 推导出了布洛芬热氧分解活化能动力学方程和动力学补偿效应数学表达式, 其降解过程符合收缩圆柱体的相界反应模型函数。

OBJECTIVE To determine thermal decomposing behavior of ibuprofen,speculate the probable mechanism of thermal decomposing reaction and calculate the kinetic parameters.METHODS Thermal decomposing behavior of ibuprofen was studied in the air by TG-DTG techniques.Four thermal analysis kinetic methods were used to speculate the probable mechanism of thermal decomposing reaction and calculate the kinetic parameters.RESULTS Ibuprofen’s activation energy of thermal decomposing with oxygen,E_α=94.8 kJ·mol -1,lnA=18.46 s -1;the decomposing process fit the model function of reaction on surface for shrinking round column.The kinetic equation:dα/dt=Ae -E_α/RT2(1-α) 1/2,the maths equation of kinetic compensating effect:lnA=0.251 4E_α-6.763 7.The correlation coefficient r=0.999 4.CONCLUSIONS We speculated the most probable mechanism of ibuprofen’s activation energy thermal decomposing reaction with oxygen and the maths equation of kinetic compensating effect. The decomposing process fits the model function of reaction on surface for shrinking round column.