Study on Direct Synthesis of Diphenyl Carbonate through Heterogeneous CatalysisI. Effect of Preparation Method of Supports on Catalyst Activity

The compound metal oxides La x Mn y Pb z O used as Pd catalyst supports for direct synthesis of diphenyl carbonate (DPC) through heterogeneous catalytic reaction were prepared by sol gel, co precipitation and freeze drying methods and calcined at 700～800 ℃. The catalyst samples were prepared by impregnation of the supports with PdCl 2 or Na 2PdCl 4 solution. The supports and the catalyst samples were characterized by XRD, TEM and SEM techniques. The results showed that the main crystal phase in the supports is La 0.3 Mn 0.5 PbO, and that the particle and pore size distribution of the support prepared by sol gel method is better than by the others. The synthesis of DPC was carried out in a high pressure reactor under the conditions of m (cat)=2 g, m (PhOH)=50 g, m (C 16 H 36 BrN)=0 986 g, p =8 MPa, p (CO)/ p (O 2)=100, θ =80 ℃ and t =5 h. It was found that the performance of the catalyst with the support prepared by sol gel method is better than by the others, and the selectivity for DPC can be greater than 99 5%.