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

Abstract

Abstract 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.