Incorporation of flexible ionic polymers into a Lewis acid-functionalized mesoporous silica for cooperative conversion of CO2 to cyclic carbonates

A rational integration of multiple reactive centers into a combined unit to facilitate their cooperative effects is a smart approach for accelerating the catalytic activity. Here, to achieve this goal, linear imidazolium-based ionic polymers were confined into the nanopores of mesoporous silica nanospheres anchored with homogeneously distributed zinc salts. Owing to the flexible character and the reinforced cooperative effects of the ionic liquid (nucleophile) and zinc species (Lewis acid) in the confined mesoporous structure, the resultant composite exhibited dramatically improved catalytic performance in the cycloaddition of CO2 with epoxides to form cyclic carbonates. This was in contrast to that observed for the individual catalytic components. Moreover, such a solid catalyst could be easily recovered and reused four times without a significant loss of activity.