Polyvinyl alcohol-potassium iodide: an efficient binary catalyst for cycloaddition of epoxides with CO2

In this study, we have for the first time demonstrated that polyvinyl alcohol (PVA) and potassium iodide (KI) can form an efficient catalytic system for synthesis of cyclic carbonates from epoxide and CO2. The catalytic reaction happens in solvent-free conditions. A synergetic effect occur between PVA and KI which considerably increases the reaction yield. This binary catalytic system is mainly suitable for mono-substituted terminal epoxides. In the optimized reaction condition, over 90% reaction yield can be achieved. The binary catalyst is reusable and can be recycled at least five times without significant loss of the catalytic activity. The PVA hydrolysis degree affect the catalytic activity as well. A possible mechanism of synergetic effect of the binary system was proposed. PVA and KI may form a non-toxic, low cost, recyclable, highly-efficiency catalyst for fixing CO2through cycloaddition with epoxides.