1,4-环己烷二甲酸催化加氢制备1,4-环己烷二甲醇的热力学分析

Thermodynamic Analysis of Hydrogenation of 1,4-Cyclohexanedicarboxylic Acid to 1,4-Cyclohexanedimethanol

采用Constantinou-Gani基团贡献法和Rozicka-Domalski基团贡献法计算了1,4-环己烷二甲酸（CHDA）加氢制备1,4-环己烷二甲醇（CHDM）过程中涉及的主副产物的标准摩尔生成焓、标准摩尔蒸发焓和摩尔定压热容;分别计算了CHDA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内,CHDA加氢体系中的各反应均为放热反应,主反应为可逆反应,副反应为不可逆反应。计算了不同反应温度和氢分压下CHDA加氢生成中间产物4-羟甲基-环己烷甲酸（CHMA）及CHMA加氢生成CHDM的平衡转化率。实验结果表明,降低反应温度和提高氢分压均有利于反应物CHDA和中间产物CHMA平衡转化率的提高。

Many products,namely 1,4-cyclohexane-hydroxymethyl carboxylic acid（CHMA）,hydroxymethyl cyclohexane（CHM）,1,4-cyclohexanedimethanol（CHDM） and 1,4-hydroxymethyl methylcyclohexane（MCHM）,can form in the hydrogenation of 1,4-cyclohexanedicarboxylic acid;（CHDA） to CHDM. The standard molar enthalpies of formation,standard molar enthalpies of vaporization and molar heat capacities at constant pressure of the products were calculated by Constantinou-Gani group contribution method and Rozicka-Domalski group contribution method. The enthalpy changes,Gibbs free energy changes and equilibrium constants of the reactions in the hydrogenation process were also calculated in the temperature range of 373.15-573.15 K. The results showed that all of the reactions were exothermic. The main reactions（Ⅰ,Ⅱ） were reversible while the side-reactions（Ⅲ,Ⅳ） were irreversible. Moreover,the equilibrium conversions for both the hydrogenation of CHDA to CHMA and the hydrogenation of CHMA to CHDM under different temperature and H2 pressure were also calculated. The results showed that low temperature and high H2 pressure were benefi cial to increasing the equilibrium conversions of CHDA and CHMA.