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.