摘要
以丙酸和含不同对位取代基的非甾体抗炎药中间体2-苯丙酸为模型化合物,以其与甲醇的酯化反应为探针反应,采用Joback和Benson基团贡献法计算了模型化合物的基础热力学数据和探针反应的标准摩尔反应焓、标准摩尔反应熵、标准摩尔反应Gibbs函数、标准平衡常数以及平衡转化率,并依此分析了温度、压力、醇酸比以及模型化合物的结构对热力学数据的影响。结果表明:探针反应均为自发过程;升温不利于反应的正向进行,而增压有利于增大反应的平衡常数和转化率;增大醇酸比可以提高反应的转化率;水分对酯化反应平衡转化率的影响较小,而邻近羧基的基团效应则对酯化反应的影响较大;对于含有结构繁杂或基团贡献值缺失的对位取代基的2-苯丙酸类化合物,均可用2-苯丙酸的热力学数据代替进行甲酯化反应的热力学分析。
Propionic acid and 2-phenylpropionic acids with different para substituents,which are intermediates of non-steroidal anti-inflammatory drug,were selected as model compounds,and the methyl esterification of model compounds was selected as the probe reaction. ΔrH,ΔrST,ΔrG,Kand equilibrium conversion have been calculated by Joback and Benson group contribution method,and the effect of temperature,pressure,molar ratio of methanol to acid and structures of model compounds on the methyl esterification have been analyzed. The results indicate that the probe reaction is spontaneous; the increase of reaction temperature is unfavorable to the methyl esterification,while higher pressure is in favor of the promotion of equilibrium constant and conversion of reactions;the increase of the molar ratio of methanol to acid can improve the equilibrium conversion of reactions; water shows little effect on the equilibrium conversion,while the effect of the substituent adjacent to the carboxyl exhibits the high influence on the esterification; for 2-phenylpropionic acids containing para substituents with complex structures or without group contribution values,the thermodynamic analysis of their methyl esterification can be carried out with their thermodynamic data replaced with those of 2-phenylpropionic acid.
作者
文武强
来家威
李亮
杜治平
WEN Wu-qiang;LAI Jia-wei;LI Liang;DU Zhi-ping(School of Chemical and Pharmaceutical,Hubei Key Laboratocy of Novel Reactor ＆ Green Chemical Technology,Key Laboratory for Green Chemical Process of Ministry of Education,Wuhan Institute of Technology,Wuhan 430073,Hubei Province,China;Hubei Xunda Pharmaceutical Co.,Ltd.,Wuxue 435400,Hubei Province,China)
出处
《化学工程》
CAS
CSCD
北大核心
2018年第2期29-34,共6页
Chemical Engineering(China)
关键词
基团贡献法
苯丙酸类非甾体抗炎药
2-苯丙酸
酯化反应
热力学
group contribution method
non-steroidal anti-inflammatory drugs
2-phenylpropionic acid
esterification reaction
thermodynamics
