Synthesis of dimethyl carbonate from urea and methanol catalyzed by iron-chloride ionic liquid

The direct synthesis of dimethyl carbonate (DMC) from methanol and urea using iron-chloride ionic liquid as catalyst was investigated with a batch operation. The results showed that the ionic liquid Et3NHCl-FeCl3 is an effective catalyst; the raised yield (about 27%) and high selectivity (ca.100%) of DMC at 180 degrees C were achieved without any specially designed equipment. The effect of the reaction conditions, such as reaction temperature, the molar ratio of urea to methanol, the amount and composition of catalysts, on the reaction was also discussed. The suggested reaction mechanism was proposed, which is very different from the reported ones in literatures.