非等温热重法研究12-溴代脱氢枞酸甲酯热解动力学

Decomposition Kinetics Research of 12-Bromodehydroabietate Methyl Ester by Non-isothermal Thermogravimetry

采用非等温热重分析法在不同升温速率下,利用Kissinger法和Flynn-Wall-Ozawa法对12-溴代脱氢枞酸甲酯的非等温热分解反应的动力学参数进行分析,同时利用atava-esták法结合34种动力学机理函数研究了12-溴代脱氢枞酸甲酯的热分解机理和动力学参数。结果表明:12-溴代脱氢枞酸甲酯的热分解机理为随机成核和随后生长,动力学函数积分形式为G(α)=[-ln(1-α)]^(3/4),反应级数为3/4级,表观活化能为85.71 kJ/mol,指前因子为1.12×10~7s^(-1),热分解动力学方程为dα/dt=1.12×10~7exp(-85.71×10~3/RT)×4/3(1-α)[-ln(1-α)]^(1/4)。方程拟合曲线的线性相关系数R_f=0.983 3,标准偏差SD=0.05。

The non-isothermal decomposition kinetics of 12-bromodehydroabietate methyl ester（BME） were studied by nonisothermal thermogravimetrie analysis at various heating rates of 5, 10, 15 and 20 K/min. The activation energy E and the preexponential A were analyzed by Kissinger and Flynn-Wall-Ozawa （FWO） method, respectively. The thermal decomposition mechanism and kinetic parameters were studied by Satava-Sestak method combined 34 kinds of dynamic functions. The results showed that the thermal decomposition mechanism of BME was controlled by the process of random nuclear formation and the nuclear growing, the reaction order n was 3/4, the integral form of kinetic function belonged to G（α） = [ - In（ 1 - α） ] 3/4, the apparent activation energy E was 85.71 kJ/mol, pre-exponentia｜ factor A was 1.12 × 10^7 s^-1 , and the corresponding thermal decomposition dynamic function was da/dt = 1. 12 × 10^7 exp （ - 85. 71× 10^3/RT） × 4/3 （ 1 - α） [ - In （ 1 - α ） ] 1/4. The function＇s correlation coefficient is 0. 983 3, standard deviation is 0.05.