Catalytic performance of polymer-supported ionic liquids in the cycloaddition of carbon dioxide to allyl glycidyl ether

Ionic liquids immobilized onto structurally modified Merrifield peptide resin (MPR) were prepared through the reaction of imidazole with alkoxylated MPR. Elemental analysis and SEM images showed that the immobilized ionic liquid groups were well incorporated onto the support. The MPR-supported ionic liquids (MPR-IL) proved to be effective heterogeneous catalysts for the solvent-free synthesis of a cyclic carbonate from allyl glycidyl ether (AGE) and carbon dioxide. MPR-ILs with longer alkyl chain linkers and sterically less hindered counteranions had higher conversions of AGE. High temperature, high carbon dioxide pressure and the presence of zinc halide co-catalyst were favorable for AGE conversion. MPR-IL can be reused for the reaction through up to three consecutive runs without significant loss of its catalytic activity.