One-pot synthesis of dimethyl carbonate in supercritical CO2

The synthesis of dimethyl carbonate (DMC) in supercritical carbon dioxide is important for resourcization of carbon dioxide and green synthesis. The synthesis of DMC were studied with carbon dioxide, propylene oxide (PO), and methanol as raw material, potassium methoxide (CH3OK) as catalyst, calcium chloride (CaCl2) as dehydration agent. The effects of factors such as the ratio of VCH3OH:VPO(1~12), stirring speed (0~500 r·min-1), pressure (5.0~10.0 MPa), temperature (110~190℃) and reaction time (0.25~3.0 h) on the synthesis of DMC were investigated. In addition, a possible reaction mechanism of one-pot synthesis of dimethyl carbonate on CH3OK was proposed. The results show that the conversion of methanol and the yield of DMC could reach 22.0% and 45.5% respectively under optimized reaction conditions (VCH3OH:VPO=10:1, stirring speed 300 r·min-1, pressure 7.0 MPa, temperature 140℃, reaction time 1 h). ©, 2014, Zhejiang University. All right reserved.