A non-phosgene route for synthesis of methylene diphenyl dicarbamate from methylene dianiline and methyl carbamate

This paper proposes a non-phosgene route for the synthesis of methylene diphenyl dicarbamate (MDC) by the methoxycarbonylation of methylene dianiline (MDA) with methyl carbamate (MC). Effects of catalysts, reaction temperature, reaction time, catalyst content and the molar ratio of reactants were investigated in the presence of methanol. The results showed that methanol-pretreated PbO catalyst exhibited high catalytic activity for this reaction. Under the condition of 433 K for 3 h, near-complete conversion of MDA and 83.1% selectivity of MDC were obtained. A possible reaction mechanism for the methoxycarbonylation reaction was proposed based on product distribution.