Chem. J. Chin. Univ.-Chin.

The stability and component change of the Pb(OAc)(2)center dot 3H(2)O catalyst, in the reaction of methylene dianiline (MDA) and dimethyl carbonate (DMC) to synthesize methyl diphenyl dicarbamate (MDC), were studied. The results show that the catalyst converts to be lead carbonate containing amine ligand, which still has a highly activity in the synthesis of MDC. The catalytic mechanism of the lead acetate catalyst was studied by in-situ infrared analysis with a temperature controlled liquid cells. The results show that the coordination ligand of catalyst plays an important role in the formation of intermediate tetrahedron, and the transformation between bidentate and monodentate is one of the key steps in catalysis. A possible reaction mechanism for the methoxycarbonylation reaction was proposed based on the in-situ FTIR analysis.The stability and component change of the Pb(OAc)(2)center dot 3H(2)O catalyst, in the reaction of methylene dianiline (MDA) and dimethyl carbonate (DMC) to synthesize methyl diphenyl dicarbamate (MDC), were studied. The results show that the catalyst converts to be lead carbonate containing amine ligand, which still has a highly activity in the synthesis of MDC. The catalytic mechanism of the lead acetate catalyst was studied by in-situ infrared analysis with a temperature controlled liquid cells. The results show that the coordination ligand of catalyst plays an important role in the formation of intermediate tetrahedron, and the transformation between bidentate and monodentate is one of the key steps in catalysis. A possible reaction mechanism for the methoxycarbonylation reaction was proposed based on the in-situ FTIR analysis