苯酚与碳酸二甲酯烷基化反应体系的热力学分析  

THERMODYNAMICS ANALYSIS FOR THE REACTION SYSTEM OF THE ALKYLATION OF PHENOL WITH DIMETHYL CARBONATE

作　　者：胡海生[1] 薛冰[1] 许杰[1] 徐崇福[1] 李永昕[1] 

机构地区：[1]常州大学石油化工学院,江苏常州213164

出　　处：《精细石油化工》2012年第1期45-49,共5页Speciality Petrochemicals

基　　金：国家自然科学基金(21076027);江苏省自然科学基金(BK2011231);江苏省"青蓝工程"青年骨干教师项目资助

摘　　要：采用Benson基团贡献法,计算了苯甲醚(MPE)的相关热力学数据。在300～1 000K和5～30MPa范围内,计算了苯酚与碳酸二甲酯烷基化反应生成甲基苯酚异构体和苯甲醚各反应的焓变ΔrHm、吉布斯自由能变ΔrGm和平衡常数Kθ。结果表明:苯酚与DMC的烷基化反应是可以自发进行的,且碳烷基化反应平衡常数远高于氧烷基化反应平衡常数,在3个碳上烷基化反应中,生成间甲酚的平衡常数最大,生成对甲酚的平衡常数最小;随着压力的升高,各反应的自由能均略有增加,表明升高压力不利于烷基化反应的进行,在同一压力下,碳烷基化反应的平衡常数远高于氧烷基化反应,为苯酚与碳酸二甲酯烷基化反应条件的控制和催化剂的探索研究提供了热力学依据。By using the Benson group contribution method, the related thermodynamics data of anisole are calculated. For alkylation of phenol with dimethyl carbonate （DMC） to produce anisole and cresols, the enthalpy change ArHm, free energy change ArG,. and equilibrium constant K^θ of each reaction at 300 - 1 000 K and 5 - 30 MPa are also calculated and then discussed according to the principles of chemical thermodynamics. The results show that the alkylation of phenol with DMC is thermodynami-cally feasible, and the equilibrium constant of C-alkylation is much higher than that of O-alkylation. Among the three C-alkylation reactions, the equilibrium constant of the reaction producing m-cresol is the highest and that of the reaction producing p-cresol is the lowest. With the increase in pressure, a slight increase in the free energy is observed, which indicates that higher pressure is not in favor of the alkylation of phenol with DMC. Under the same pressure, the equilibrium constants of C-alkylation are much higher than that of O-alkylation. The results provide a set of basic thermodynamic data for studying alkylation of phenol with DMC and developing catalysts for the reaction.

关 键 词：苯酚 碳酸二甲酯 烷基化 基团贡献法 热力学分析 

分 类 号：TQ021.2[化学工程]