Amine-Catalyzed, One-Pot Coproduction of Dialkyl Carbonates and 1,2-Diols from Epoxides, Alcohols, and Carbon Dioxide

Amine-catalyzed, one-pot coproduction of dimethyl carbonate (DMC) and 1,2-diols from epoxides, methanol, and carbon dioxide has been reevaluated and investigated in detail. 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) serves as a desirable catalyst for the reaction. Heating of a mixture of glycidyl phenyl ether, methanol, a catalytic amount of DBU, and carbon dioxide at a total pressure of ca. 15 MPa at 150 °C gives DMC and the corresponding 1,2-diol in excellent yield (up to 97%). The influence of the reaction conditions on the DMC yield is discussed. The extension of this procedure to the synthesis of other symmetric dialkyl carbonates is also described.