Synthesis of methyl N-phenyl carbamate from methanol and phenyl urea

In this paper, methyl N-phenyl carbamate (MPC) was firstly synthesized from methanol and phenyl urea. The effects of catalysts, including PbO, Pb3O4, Pb/SiO2, ZnCl2, FeCl3, Mo/HZSM-5 and Pb/HZSM-5, material ratio and reaction condition on the synthesis of MPC were investigated, and the optimum reaction conditions were obtained. It was found that PbO showed a higher catalytic activity and MPC selectivity than those of other catalysts. The selectivity of MPC decreased while the conversion of phenyl urea increased with the increase of reaction temperature. Prolonging the reaction time enhanced the conversion of phenyl urea while suppressed the formation of MPC. Higher methanol/phenyl urea molar ratio favored the formation of MPC. The conversion of phenyl urea and the yield of methyl N-phenyl carbamate were reached 95.2% and 80.6%, respectively, under the optimum reaction conditions at 140 degreesC after 4 h reaction. The reaction mechanism was discussed based on the distribution of products.