Halogen-free processes for organic carbonate synthesis from CO2

Recent progress on the synthesis of organic carbonates by halogen-free processes has been reviewed. With CO2 as a cheap and non-toxic feedstock, alcohols, epoxides and olefins can convert to abundant organic carbonates, e.g. dialkyl carbonates, five- or six-membered cyclic carbonates and polycarbonates. To avoid environmental pollution and equipment corrosion, new synthesis routes which exclude traditional halogen-containing catalysts and solvents have caused much attention. Effective alternatives mainly include the organic/inorganic bases and metal-complexes catalysts. In addition, novel carriers for the catalysts are being applied in these processes to improve the activity and facilitate the recovery.