Green Synthesis of Alkyl Carbamates via Non-Phosgene Process From Reactions of NH3 and Dialkyl Carbonate Over Zn-Acetate-Triazolato Catalysts

Among them, Zn(OAc)ATZ exhibited exceptional catalytic performance due to its high surface area (441.11 m 2 /g), hierarchical porosity, and appropriate coordination environment.

Under optimized conditions, 89% conversion of diethyl carbonate (DEC) with 88% ethyl carbamate (EC) yield could be achieved over Zn(OAc)ATZ at 80°C for 16 h. For dimethyl carbonate (DMC), a remarkable 98% conversion and 97% methyl carbamate (MC) yield were obtained at 30°C within 6 h, while dibutyl carbonate (DBC) required 24 h at 90°C to reach 95% conversion and 93% butyl carbamate (BC) yield. Characterization of XPS and FT-IR revealed that the synergistic interaction between Zn–N bonds and carboxylate groups stabilized the active sites, enabling efficient substrate activation.