A Facile, Direct Synthesis of Styrene Carbonate from Styrene and CO2 Catalyzed by Au/Fe(OH)3–ZnBr2/Bu4NBr System

A three-component catalyst composed of Au/Fe(OH)3, ZnBr2, and Bu4NBr was shown to be very efficient for direct oxidative carboxylation of styrene to styrene carbonate. An enhanced styrene carbonate yield (53%) was obtained under mild reaction conditions of 80 °C, 10 h, and 4 MPa CO2 pressure. In this reaction, CO2 acts as both a reagent and a solvent. The influence of various reaction parameters, such as catalyst pretreatment, CO2 pressure, and reaction time has been investigated carefully. Furthermore, the active sites in supported Au catalyst are studied. The results obtained suggest that synergistic effect of gold ions and ferric hydroxide over Au/Fe(OH)3 catalyst might be important for its better catalytic performance in epoxidation of styrene as compared with supported gold catalyst on oxides.