A direct synthesis of styrene carbonate from styrene with the Au/SiO2–ZnBr2/Bu4NBr catalyst system

This paper reports a direct route for the preparation of cyclic styrene carbonate from styrene, which avoids the preliminary synthesis and isolation of styrene oxide. A catalyst system consisting of Au/SiO2, zinc bromide, and tetrabutylammonium bromide (Bu4NBr) has been applied to the one-pot synthesis of styrene carbonate from styrene, organic peroxide, and CO2. Au/SiO2 is active for the epoxidation of styrene, and zinc bromide and Bu4NBr cooperatively catalyze the subsequent CO2 cycloaddition to epoxide. The influence of various reaction parameters, such as CO2 pressure, reaction temperature, reaction time, catalyst amount, ratio of oxidant to styrene, and oxidant type, has been investigated in detail.