Facile one-pot synthesis of ZnBr2 immobilized ion exchange resin for the coupling reaction of CO2 with propylene oxide

[Display omitted] •Zn salt was immobilized on an ionic exchange resin (ZnX2/IER).•ZnBr2 formed [ZnBr2Cl2]2− on the surface of the cationic IER.•ZnBr2/IER showed the highest activity for CO2 conversion.•The activity was maintained during 98 h of continuous reaction. The synthesis of cyclic carbonate from CO2 and alkylene oxide is one of the best environment-friendly technologies for converting CO2 to valuable chemicals. In this study, a [ZnX2Cl2]2−immobilized ion exchange resin (ZnX2/IER) was synthesized using four kinds of zinc precursors, ZnX2 (X = Cl, Br, OAc, and NO3) and a chloride-anion exchange resin (IER). The synthesized ZnX2/IER was then used for the cycloaddition reaction of CO2 and propylene oxide (PO) to synthesize propylene carbonate (PC). Among the synthesized catalysts, ZnBr2/IER showed the highest activity, with a 76.7% PC yield achieved at 80 °C for 2 h, and 99.1% after 8 h. The catalytic activity was maintained during 5 times uses. The fresh and used ZnBr2/IER were characterized by FT-IR, SEM-EDS, and ICP-OES, and no noticeable changes in the morphology and zinc concentration were observed. The continuous reaction using a fixed-bed system for 96 h demonstrated that the synthesized catalyst can be employed in commercial PC synthesis processes.