铅化合物催化二氨基二苯甲烷与碳酸二甲酯反应机理的红外光谱研究

研究了Pb(OAc)₂·3H₂O催化二氨基二苯甲烷(MDA)与碳酸二甲酯(DMC)反应合成二苯甲烷二氨基甲酸甲酯(MDC)的稳定性和成分变化, 发现乙酸铅在反应过程中会形成含氨基配体的碱式碳酸铅, 该化合物对MDC的合成仍具有较高活性. 采用红外光谱结合原位控温液体池技术研究了其催化机理, 结果表明, 铅催化剂的配体对其催化活性起重要作用, 双齿配位方式向单体配位方式的转变是催化剂起作用的关键步骤; 并在此基础上提出了铅催化剂催化MDA与DMC反应的机理.

FTIR Spectroscopic Studies on Catalytic Mechanism of Lead Compounds in the Reaction of Methylene Dianiline and Dimethyl Carbonate

The stability and component change of the Pb(OAc)2·3H2O 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.