不同反应原料合成碳酸二苯酯的热力学研究  

Thermodynamic Study on Diphenyl Carbonate Synthesis with Different Feedstocks

作　　者：国鑫[1] 施有民 郑化安 程进[1] 赵宪泽 杨伯伦[1] 

机构地区：[1]西安交通大学化学工程与技术学院,陕西西安710049 [2]陕西煤业化工技术研究院有限责任公司,陕西西安710070

出　　处：《高校化学工程学报》2016年第4期754-760,共7页Journal of Chemical Engineering of Chinese Universities

摘　　要：采用密度泛函理论(DFT),对碳酸二苯酯(DPC)的不同合成反应路径进行了热力学分析。首先优化了反应中涉及的各种物质在气体状态下的稳定结构,在此基础上计算了各物质液体状态下的热力学性质,获得了碳酸二甲酯-苯酚(DMC-Ph OH),碳酸二甲酯-乙酸苯酯(DMC-PA)两种不同酯交换反应路径的焓变、熵变、吉布斯自由能变以及平衡常数。计算结果表明,两种合成反应均为吸热反应;从热力学角度来看,DMC-PA反应路径优于DMC-Ph OH反应路径,其反应平衡常数更大,利于DPC的生成。但两种合成路径各步反应的平衡常数KC均偏小,为提高DPC收率,需要在反应进行过程中,不断移走产物以打破热力学平衡限制。同时,从热力学角度分析,若DMC同Ph OH的反应采用"两步法",DMC同PA的反应采用"一步法",则较有利于DPC的生成。Thermodynamics of different transesterification processes for diphenyl carbonate （DPC） synthesis were studied based on the density functional theory （DFT）. The stable structures of all related compounds in gas state were optimized. Their thermodynamic properties in liquid state such as enthalpy changes, entropy changes and Gibbs free energy changes were then calculated. The equilibrium constants of transesterification via dimethyl carbonate-phenol （DMC-PhOH） and dimethyl carbonate-phenyl acetate （DMC-PA） routes were obtained. The results show that both routes are endothermic. The DMC-PA route is more thermodynamically favorable than the DMC-PhOH route because of larger equilibrium constants that benefit DPC formation. The equilibrium constants Kc of both routes are small. The instant removal of byproducts during reaction is preferred to increase DPC yield. In addition, a two-step process is suitable for the reaction between DMC and PhOH, while a one-step process is suitable for the reaction between DMC and PA thermodynamically.

关 键 词：酯交换反应 碳酸二苯酯 热力学分析 乙酸苯酯 苯酚 

分 类 号：TQ013.1[化学工程]