Sn-catalyzed synthesis of propylene carbonate from propylene glycol and CO2 under supercritical conditions

Dibutyltin oxide or dibutyltin dimethoxide was first used as a remarkable selective catalyst for the synthesis of propylene carbonate from propylene glycol and carbon dioxide. The effects of the reaction parameters, such as reaction time, temperature and CO, pressure on the amount of propylene carbonate were also experimentally studied. Under the optimized conditions, the amount of propylene carbonate was nearly proportional to PG concentration. The use of N,N-dimethylformamide as a co-solvent in this study significantly enhanced the catalytic activity, and the ketals as dehydrating agents greatly improved the yield of PC, which can be limited by the equilibrium. A postulated mechanism for the dibutyltin oxide-catalyzed carboxylation of propylene glycol was also discussed. (c) 2005 Elsevier B.V. All rights reserved.