Polyhydroxy Ionic Polymer Catalysts for Highly Selective Cycloaddition of Carbon Dioxide and Epoxides

New polyhydroxy ionic polymers were designed and prepared to heterogeneously catalyze CO2 cycloaddition reaction with complete chemoselectivity and up to 99 % yields. Using copolymer of 1-(2-hydroxyl-ethyl)-3-vinyl-imidazolium bromide ([HeVim][Br]) and styrene, the highest yield of propylene carbonate was obtained. And, it is significantly higher than that obtained with the same amount of hydroxy monomer [HeVim][Br] (only 24 % yield), thus showing the concerted promotion effect of polyhydoxyl groups during ring opening of epoxides. The catalyst presented excellent recycling performance (10 cycles). Various terminal cyclic carbonates were synthesized with above 95 % yields. A synergistic function of hydroxyl group as efficient hydrogen bonding donor and bromide anion as nucleophilic agent was put forward.