Performance of ionic liquid as catalysts in the synthesis of dimethyl carbonate from ethylene carbonate and methanol

The synthesis of dimethyl carbonate (DMC) from methanol and ethylene carbonate (EC) without using any solvent was investigated in the presence of ionic liquids as catalysts. The conversion of ethylene carbonate was affected by the structure of ionic liquid. For a series of 1-alkyl-3-methylimidazolium ionic liquids, the one with shorter alkyl chain and the one with more nucleophilic anion showed higher reactivity. The conversion of EC also increased with CO2 pressure and reaction temperature. Esterification of EC and methanol can be considered as a pseudo-first order reaction with respect to EC concentration. The activation energy was estimated as 50.1 kJ/mol.