Catalytic Synthesis of Methyl N-Phenyl Carbamate by Ce-Based Complex Oxides

Ce-based composite oxides were used for catalyzing the methyl N-phenyl carbamate (MPC) synthesis from aniline and dimethyl carbonate. Among them, CuO–CeO2 exhibited the best catalytic performance. Characterization results showed that the second metal (Cu, Zn, Mn, Co, and Zr) can be doped into the CeO2 lattice and led to strong interactions, modifying the content of Ce3+, oxygen vacancy, and acidity of the catalyst. Notably, Ce3+, oxygen vacancies, and weak Lewis acid sites are beneficial to MPC synthesis. Additionally, CuO–CeO2–M, prepared by mechanical mixing, exhibited better catalytic activity than CuO–CeO2–C prepared by co-precipitation. This was due to the preparation method affecting the interaction between CuO and CeO2. CuO primarily interacted with CeO2 through interfacial contact in CuO–CeO2–C, whereas the interaction in CuO–CeO2–M involves both this interfacial contact effect and the presence of solid solution structures, thereby influencing the content of Ce3+, oxygen vacancy, and acidity.