分子筛催化甲苯和叔丁醇烷基化反应的机理及热力学分析

Mechanism and Thermodynamic Analysis of Alkylation of Toluene With tert-Butyl Alcohol Over Zeolite Catalyst

研究了沸石分子筛催化甲苯和叔丁醇烷基化反应机理,并采用热力学计算方法对甲苯叔丁基化过程所涉及的主要反应迚行了热力学分析。研究结果表明,甲苯和叔丁醇烷基化属于芳环上的亲电子取代反应,遵循正碳离子机理。甲苯和叔丁醇烷基化反应是一个自发迚行的放热反应,温度越高,反应热效应越小,反应自发迚行的程度越低。

The reaction mechanism on alkylation of toluene with tert-butyl alcohol over zeolite was studied and the thermodynamic analysis on the main reactions was also carried out in detail. The result showed that the alkylation of toluene with tert-butyl alcohol is an electrophilic substitution reaction on the aromatic ring. The tert-butylation of toluene was commonly considered to proceed via carbenium ion mechanism. The alkylation of toluene with tert-butyl alcohol was spontaneous exothermic reaction. The heat effect decreased, while the Gibbs free energy increased with the increase of temperature.