3,6-二氯水杨酸合成反应热力学性质的计算化学分析  

Computational Chemistry Analysis on Thermodynamics of 3,6-Dichlorosalicylic Acid Synthesis

作　　者：颜星星[1] 程振民[1] 蒋亦文[1] 余忠宝 唐显重 费月明 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海200237 [2]浙江升华拜克生物股份有限公司,浙江德清313220

出　　处：《华东理工大学学报（自然科学版）》2012年第3期285-292,共8页Journal of East China University of Science and Technology

基　　金：中央高校基本科研业务费专项资金资助

摘　　要：利用密度泛函理论(DFT)的B3LYP方法对Kolbe-Sclamitt羧化法合成3,6-二氯水杨酸进行了热力学分析,在6-311++g(3df,3pd)水平上优化计算了反应物与产物的几何构型与电子分布,经振动频率分析后计算了反应温度300～600 K下各物质的总能量与热力学参数,得到了主副反应的焓变、吉布斯自由能变以及平衡常数。结果表明,Kolbe-Schmitt主副反应均为放热反应,主反应在低温低压下不能自发进行,而副反应在常压下就可进行,在热力学上是完全可行的。平衡常数的分析表明反应为可逆反应,CO_2压力的增加有利于平衡的正向移动,而副反应生成的2,5-二氯苯酚则导致平衡逆向进行。Thermodynamics of synthesis of 3,6-dichlorosalicylic acid by Kolbe-Schmitt reaction was studied by using the B3LYP method of density functional theory. All of the structures of the reactants and products were optimized under 6-311 ＋＋g （3dr, 3pd）level. The changes in reaction enthalpy, Gibbs free energy and equilibrium constant under reaction temperature （300--600 K） for the primary and side reaction were calculated and analyzed with the basic thermodynamic data obtained from vibration frequency analysis. The result shows that Kolbe-Schmitt reaction processes are exothermic but the primary reaction can＇t on thermodynamic which can proceed easily under mild conditions. In addition is reversible that the equilibrium conversion could be promoted by increasing crucially inhibited by phenol formed in side reaction. the Kolbe-Schmitt reaction the pressure of CO2 while

关 键 词：3 6-二氯水杨酸 Kolbe-Schmitt 羧化反应 密度泛函 热力学分析 

分 类 号：O623.11[理学—有机化学]