Lewis acid catalyzed reaction of dimethyl carbonate with amines: Experimental and theoretical study

The effect of various catalysts on the reaction of dimethyl carbonate with aniline leading to the formation of methyl phenylcarbamate was studied. In the absence of catalysts, the interaction practically does not occur. Such Lewis acids as zinc chloride, ferric chloride, exhibit unsatisfactory properties. Zinc and lead acetates have high catalytic properties. The presence of crystalline water in these salts reduces their catalytic activity. In the presence of catalyst, the reaction of aniline with dimethyl carbonate is autocatalytic, which is indicated by the presence of an induction period in it. The induction period disappears if methanol is deliberately introduced into the reaction mixture. A model reaction of dimethyl carbonate with methylamine catalyzed by zinc acetate was studied at the PBE0 and WB97XD levels. The calculation results show that true catalyst is zinc methoxide or zinc oxide.