碳酸铯催化苯五甲酸与CO2羧基化反应的研究

Study on Carboxylation of Phenylpentacarboxylic Acid and CO2 Catalyzed by Cesium Carbonate

通过密度泛函理论的B3LYP方法,在lanl2dz水平上考察了苯五甲酸以碳酸铯为催化剂与CO2羧基化生成苯六甲酸反应的热力学性质,该反应在热力学上是自发进行的,且是放热的,反应平衡常数随着温度的升高而减小。通过单因素实验考察了混合方式、反应温度、CO2压力和反应时间对该反应的影响。结果表明:苯五甲酸与碳酸铯先水解混合成盐有利于反应的进行;在相同的反应时间内,反应温度对羧基化反应影响较大,在未达反应所需温度时,即使有一定的压力,反应也无法进行;此外,随着反应时间的延长,苯六甲酸的收率和选择性呈先上升后降低的趋势。

The B3LYP method based on density functional theory at the level of lanl2dz was used to investigate the thermodynamic properties of the carboxylation reaction from phenylpentacarboxylic acid to mellitic acid with cesium carbonate as the catalyst.This reaction is spontaneous and exothermic in thermodynamics.The reaction equilibrium constant decreases with increasing temperature.The effects of mixing mode,temperature,pressure,and time on the carboxylation reaction were examined by single-factor experiments.The results show that the hydrolysis of phenylpentacarboxylic acid and cesium carbonate to form salts is beneficial to the subsequent reaction.In the same reaction time,temperature has a great influence on the carboxylation reaction.When the required temperature is not reached,the reaction cannot proceed even under a certain pressure.In addition,the yield and selectivity of mellitic acid increases first and then decreases with time.