| Diphenyl carbonate (DPC) is an important organic carbonate. With the development of the synthesis of high-quality polycarbonate (PC) by DPC and bisphenol A with the environment-friendly new technology, the research of DPC has gradually been concerned. Oxidative carbonylation of phenol to synthesize DPC is an cleaning and one-step synthetic method. However, the deactivation of the catalyst and low activity were occurred in the presence of water arising during the reaction. Therefore, this paper focuses on the synthesis of DPC by the oxidative carbonylation of phenol under the continuous reaction process, in which the solvent was added to remove water by azeotrope.The appropriate continuous reaction process was designed, and the process of removing water by azeotropic solvent has been achieved at low pressure during the reaction. 1,2– dichloroethane, which has larger polar and better-performing of removing water by azeotrope, was selected as the optimum solvent. Furthermore, the optimum reaction condition was 80℃, 5MPa, 4h, molar ratio of CO:O2=4:1 and F=100mL/min. It was best to remove water at 70wt% of 1,2– dichloroethane, resulting in obvious decrease of water concentrationthe in reaction system.The comparison between intermittent and continuous reaction process showed that the water produced during the reaction could be removed obviously in continuous reaction process. The water was reduced from 0.32% to 0.04% and from 1.36% to 1.04% at low and high pressure reaction process, respectively. As a result, the deactivation of the catalyst and production of by-products were restrained, which can improve obviously the yield and selectivity of DPC.According to XPS results, the amount of C on the catalyst surface has greatly increased after reaction. This showed that the palladium of the catalyst surface was covered by the organic compounds in reaction system,which caused the decline of the amount of Pd(II) and the deactivation of the catalyst.
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