Cerium dioxide catalyzed synthesis of methyl N-phenylcarbamate from carbon dioxide, aniline and methanol in the presence of n-butyllithium

Direct synthesis of methyl N-phenylcarbamate (MPC) from carbon dioxide (CO2), aniline and methanol catalyzed by cerium dioxide (CeO2) in the presence of n-butyllithium (BuLi) was developed. The catalytic activity of CeO2 was significantly improved by the addition of BuLi. The conversion of aniline and the yield of MPC were dependent on the amount of CeO2 and BuLi, reaction conditions including the pressure of CO2, reaction time and temperature, and 9.4% yield of MPC was obtained under the optimized conditions. The formation pathway of MPC was also investigated in detail by varying reactants based on previously reported investigations, and phenyl isocyanate (PI) was believed to be the intermediate for the synthesis of MPC. A possible reaction pathway for the direct synthesis of MPC from CO2, aniline and methanol was proposed. (C) 2015 Elsevier B.V. All rights reserved.