Study On The Catalysis Of The Synthesis Of Diphenyl Carbonate By Oxidative Carbonylation

Diphenyl Carbonate (DPC) is a chemical material mainly used to produce Poly-Carbonate in polyester industry. It has attracted more and more attention. The direct synthesis of diphenyl carbonate(DPC) is a promising synthetic method.Catalytic system Pd-Co/Hopcalite -TBAB-H2BQ- molecular sieve of 3A was determinated in this paper. The optimum conditions for preparation of the catalyst were determinated by orthogonal experiments. And the experimental results showed that the molar proportion of Pd and Co was 1:7, and the temperature of calcination was 400oC, and the calcination time was 2h. The yield and selectivity of DPC in the process can reach to 38.7% and 99.8%. The molar proportion of Pd and Co was the most important influencing factor, which was resured to be 1:7 by one-factor research.The before reacted catalyst and the after reacted catalyst were characterized by XRD, SEM, EDS and XPS. The reaction mechanism of the synthesis of DPC by oxidative carbonylation catalysted by mixed oxides was researched and discussed. There were stable crystal phases such as CuMn2O4,CoMn2O4,Pd0.5Pd3O4 in the catalytic system may contribute to reduce the leaching of active component. The oxygen atoms in the crystal lattice lose electrons and form oxygen vacancies. The increase of oxygen vacancies destroys the crystal integrity and prompts the oxygen adsorption on the crystal surface. This accelerates the oxygen gas transition to crystal oxygen and promotes the regeneration of catalyst, therefore, the catalytic activity is also improved.The optimum reaction conditions of the synthesis of diphenyl carbonate by oxidative carbonylation were carried out. The results showed that reaction temperature was 100℃, reaction time was 6h, the input molar quantity of phenol was 40mmol. The yield and selectivity of DPC in the process can reach to 43.5% and 99.6%. The pressure of the reaction was resured to be 6.0MPa (the ratio of O2 15%) by one-factor research. At last, the feasibility of [bmim]BF4,[bmim]PF6 and [bmim]OH was discussed.