有机蒙脱土热分解动力学

Pyrolytic Kinetics of Organic Montmorillionite

用十八烷基三甲基溴化铵(STAB)和蒙脱土(MMT)制备有机蒙脱土(OMMT),采用热重-差热(TG-DTA)法研究OMMT热分解动力学。结果表明:OMMT的热分解发生在170～510℃之间,其数据通过Agrawal积分方程线性拟合,以线性相关系数(r)为判据,得到OMMT热分解反应的机理函数为G(a)=[-ln(1-a)]4、活化能E=36.16 kJ.mol-1、频率因子A=88 014.17min-1、动力学补偿效应方程为lnA=0.431 4E-4.463 2;根据热分解动力学求得的DTA曲线形状因子Ф表明OMMT的DTA曲线对称性好,这与其TG-DTG-DTA中DTA曲线吻合。

Organic montmorillionite（OMMT） was prepared from octadecyl trimethyl ammonium bromide （STAB） and montmorillionite（MMT）, and thermo gravimetry and differential thermal analysis （TG- DTA） were adopted to investigate pyrolytic kinetics of OMMT. The results showed that pyrolysis of OMMT occurred at 170-510℃, and the data were analyzed by Agrawal integral equation. Combined with the linearly dependent coefficient （r）, the integral kinetic equation G（a）=l-In（1-α）]4 of the pyrolysis of OMMT, active energy（E） 36.16 kJ · mol-1, frequency factor（A） 88 014.17 min-1 , and the kinetic com- pensation effect equation lnA=0. 431 4E--4. 463 2 were found. Form factor （Φ） of DTA curve calculated from pyrolysis kinetics showed that the symmetry of DTA curve of OMMT was good, and was identical with the DTA curve in TG-DTG-DTA.