4,6-二羟基嘧啶的合成热力学分析

摘要

采用Benson和Joback基团贡献法,对丙二酸二甲酯和甲酰胺在甲醇钠溶液中制备4,6-二羟基嘧啶的过程的反应焓变△rH(O)、反应熵变△rS(O)、反应吉布斯自由能变△rG(O)及其平衡常数Kp进行了热力学估算.结果表明:△rH(O)＞0,反应为吸热反应;△rG(O)＜0,此反应过程为自发过程;Kp随着温度的升高而增大.%The reaction heat△rHΘ , reaction entropy changeArSΘ , Gibbs free energy changeArGΘ and equilibrium constants Kp for the synthesis of 4,6-dihydroxy pyrimidine by reaction of dimethyl mal-onate and formamide in sodium methoxide-methanol solution were calculated by Benson and Joback group contribution methods. The results show that the reaction is endothermic, A,HΘ>0 and is spontaneous,△rGΘ <0; Kp increases with increasing temperature. The relevant thermodynamic reference datas are provided for the further research and industrial production of synthesis of 4,6-dihydroxy-py-rimidine.