煤相关含氧模型化合物苯甲醚热解机理的量子化学研究

Theoretical study on pyrolysis mechanism of O-containing model compound anisole in coal

采用量子化学密度泛函理论方法对煤相关含氧模型化合物苯甲醚热解异构化反应的热力学和动力学进行了分析,确定了苯甲醚热解异构化生成邻位、对位甲酚的反应路径为两条平行的连串反应,且分别生成产率相当的邻位和对位甲酚。苯甲醚中O—CH3键的均裂为决速步骤,其活化能为285.90kJ.mol-1(1000K),从理论上解释了邻位和对位甲基取代的环己二烯酮中间体在反应中的存在。

The isomeric pyrolysis mechanism of anisole was investigated using the density functional theory（DFT）of quantum chemistry.Two parallel consecutive reaction paths were determined,which involved the formation of intermediate o-and p-methyl cyclohexadienone followed by H transfer.The theoretical evidence of this important intermediate was proposed.The mechanism resulted in the formation of the two major products,o-and p-cresol.The yields of major products were almost the same,which was in accordance with the experimental fact.Kinetic analysis showed that the homolysis of O—CH3 bond in anisole was the rate-determining step,and the activation energy was 285.90 kJ·mol^-1 at 1000 K.