丙酮气相缩合合成3,5-二甲基苯酚的热力学分析  

Thermodynamic Analysis on Synthesis of 3,5-Dimethylphenol by Vapor-phase Condensation of Acetone

作　　者：雒康 杨友得 苏蕾[1] 潘悦[1] 陈立宇[1] 

机构地区：[1]西北大学化工学院,陕西西安710069

出　　处：《过程工程学报》2017年第4期797-803,共7页The Chinese Journal of Process Engineering

基　　金：陕西省教育厅服务地方专项计划项目(编号:14JF024)

摘　　要：对丙酮气相合成3,5-二甲基苯酚的反应过程进行了热力学分析,根据产物分析结果和反应历程,将反应分为3个阶段:丙酮的羟醛缩合反应、丙酮和异丙叉丙酮的1,6-Michael加成反应和异佛尔酮芳构化反应;采用Benson基团贡献法估算了部分化合物的热力学参数,推导了3步反应的焓变、吉布斯自由能变和反应平衡常数与温度的关系.结果表明,在373~973 K温度范围内,3个反应均能自发进行,异丙叉丙酮生成异佛尔酮为放热反应,丙酮生成异丙叉丙酮为可逆反应,异佛尔酮生成3,5-二甲基苯酚的反应为不可逆反应.Thermodynamic analysis of vapor-phase condensation of acetone to 3,5-dimethylphenol system was carried out. The reaction process was divided into three stages according to the production and reaction mechanism： acetone aldol condensation, 1,6-Michael addition reaction of acetone and mesityl, isophorone aromatization. By using Benson group contribution method, partial unknown parameters of thermodynamics were estimated, the enthalpy changes, Gibbs free energy changes and equilibrium constant of each reaction system were calculated in detail as a function of temperature. The results showed that at 373-973 K, three reactions are spontaneous and the process of making mesityl oxide into isophorone is exothermic reaction. The reaction of making acetone into mesityl oxide is virtually irreversible but isoDhorone into 3,5-xylenol is limited by thermodynamic equilibrium.

关 键 词：3.5-二甲基苯酚 丙酮 Benson基团贡献法 热力学分析 

分 类 号：TQ013.1[化学工程]