One-pot synthesis of dimethyl carbonate catalyzed by n-Bu 4NBr/ n-Bu 3N from methanol, epoxides, and supercritical CO 2

Abstract

A homogeneous binary catalyst system, n-Bu 4NBr/ n-Bu 3N, was found to be active for the synthesis of dimethyl carbonate from styrene oxide (SO), methanol, and supercritical CO 2. Under the optimized conditions, the dimethyl carbonate yield could reach 84% at SO conversion of 98%. Several parameters were studied, i.e. catalyst precursors, reaction time and temperature, methanol/epoxide feed ratio in moles, and CO 2 pressure. The best compromise for the one-pot synthesis was achieved with an equimolar amount of n-Bu 4NBr/ n-Bu 3N. A possible mechanism for the present n-Bu 4NBr/ n-Bu 3N-catalyzed one-pot synthesis of dimethyl carbonate was proposed.