对苯二甲酸催化加氢制备1，4-环己烷二甲酸的热力学分析

摘要

The thermodynamics of the hydrogenation of terephthalic acid(TA) to 1,4-cyclohexanedicarboxylic acid(CHDA) was studied,and the standard molar enthalpies of formation,standard molar enthalpies of vaporization and molar heat capacities at constant pressure of the main products and byproducts were calculated by the Constantinou-Gani group contribution method and Rozicka-Domalski group contribution method. The enthalpy changes,Gibbs free energy changes and equilibrium constants of the chemical reaction in the hydrogenation in the temperature range of 373.15-573.15 K were calculated also. The results showed that the benzene ring hydrogenation and decarboxylation were dominant in the hydrogenation of TA. The TA hydrogenation to CHDA is an exothermic reaction and low temperature is favorable toit,while the TA decarboxylation to benzoic acid is an endothermic reaction and high temperature is favorable to it. As low temperature is unbeneficial to the dissolution of TA,the appropriate reaction temperature should be chosen between 493.15-523.15 K.%采用Constantinou-Gani基团贡献法和Rozicka-Domalski基团贡献法计算了对苯二甲酸（TA）加氢制备1，4-环己烷二甲酸（CHDA）过程中可能涉及的主副产物的标准摩尔生成焓、标准摩尔蒸发焓和定压热容。在373.15～573.15 K的温度下，分别计算了TA加氢反应体系中各反应的焓变、Gibbs自由能变和平衡常数。计算结果表明，在373.15～573.15 K温度范围内，TA加氢反应以苯环加氢反应和脱羧基反应为主。TA加氢生成CHDA的反应是放热反应，低温有利于该反应的进行，而TA脱羧基生成苯甲酸的反应是吸热反应，高温有利于该反应的进行。但因低温不利于TA的溶解，综合考虑，选择TA加氢制备CHDA的反应温度为493.15～523.15 K较适宜。