The increasing world market of organic carbonates demands for the development of new synthetic methodologies, alternative to phosgene which represents the starting material for their conventional synthesis. Innovative technologies based on CO2 are attracting much attention as they are environmentally acceptable and may respond to the atom-economy principle. The oxidative carboxylation of olefins catalyzed by homogeneous or heterogeneous catalysts has a good potential as it uses simple starting materials to produce valuable chemicals. In this paper the conversion of styrene into styrene carbonate is discussed with emphasis on the reaction mechanism and product distribution considering either homogeneous or heterogeneous catalysts. (C) 2002 Published by Elsevier Science B.V.