Ionic liquid mediated CO2 activation for DMC synthesis

Promoted catalytic reaction between methanol and CO₂ for dimethyl carbonate (DMC) synthesis is conducted over K₂CO₃/CH₃I catalyst in the presence of ionic liquid under microwave irradiation. The effect of ionic liquids incorporated with microwave irradiation on the yield of DMC is investigated. DMC was found to form at lower temperature in a relative short time, which indicated an enhanced catalytic process by ionic liquid. Among the ionic liquids used, 1-butyl-3-methylimidazolium chloride is the most effective promoter. Density functional theory calculations indicate that CO₂ bond lengths and angles changed due to the molecular interaction of ionic liquid and CO₂, resulting in the activation of CO₂ molecules and consequently the acceleration of reaction rate.