One‐Pot Preparation of Methyl N‐Phenyl Carbamate and Zn(OAc)2/SiO2 Catalyst with Enhanced Stability

Abstract

AbstractThe one‐pot preparation of methyl N‐phenyl carbamate (MPC) and supported Zn(OAc)2/SiO2‐OP was investigated. Zn(OAc)2 and SiO2 were added to the reaction between dimethyl carbonate (DMC) and aniline upon which MPC and Zn(OAc)2/SiO2‐OP were obtained simultaneously. The co‐prepared Zn(OAc)2/SiO2‐OP showed superior catalytic performance for MPC synthesis, giving a aniline conversion of 96.3% and a MPC selectivity of 99.7%. Compared with catalyst prepared by incipient impregnation, Zn(OAc)2/SiO2‐OP was more stable during the reaction, and the aniline conversion was 85.0% with MPC selectivity of 88.2% for the seventh time. The catalyst was characterized and the results suggested that Zn(OAc)2, Zn5(OH)8(OAc)2⋅2H2O, ZnO and Zn4O(OAc)6 are present on SiO2 surface. Zn(OAc)2 and Zn4O(OAc)6 are the active sites for MPC synthesis. The superior stability of the Zn(OAc)2/SiO2‐OP catalyst came from the presence of Zn4O(OAc)6.