Porous polymer bead-supported ionic liquids for the synthesis of cyclic carbonate from CO2 and epoxide

Highly cross-linked porous poly(N-vinylimidazole-co-divinylbenzene) (PVIm) beads of various pore sizes and specific surface areas were synthesized by suspension polymerization. The surfaces of the PVIm beads were then modified with various alkyl halides to obtain various ionic liquid-grafted porous polymer beads (PVIm-RX), which were then used as heterogeneous catalysts in the synthesis of cyclic carbonate from CO2 and epoxide. All catalytic reactions are carried out under mild conditions (90–130 °C, 0.86–2.17 MPa) in the absence of organic solvents. The effects of texture properties of the PVIm matrix, molecular compositions of the ionic liquid moieties, and catalytic reaction parameters (reaction temperature, pressure, and time) on the catalytic reactivity of cycloaddition reactions were systematically investigated. The results demonstrate that grafted ionic liquids with more nucleophilic anions, bulkier alkyl chains, or hydroxyl groups improve reactivity. Additionally, the incorporation of small amount of ethanol or water into the reaction system could significantly increase reactivity. In addition, textural properties of the polymer matrix (pore size and specific surface area) affected the catalytic reactions. The obtained PVIm-RX heterogeneous catalysts exhibited higher turnover number than those reported for ionic liquids grafted onto porous silica.

Ionic liquid-grafted porous polymer beads (PVIm-RX) were prepared and used as efficient heterogeneous catalysts in the synthesis of cyclic carbonate from CO2 and epoxide.Figure optionsDownload high-quality image (109 K)Download as PowerPoint slideResearch highlights
► Highly cross-linked porous polymer beads with various pore sizes and specific surface areas for heterogeneous catalysts.
► Effects of hydroxyl groups on the cycloaddition reaction of allyl glycidyl ether and carbon dioxide.
► Porous polymer supporting ionic liquids as heterogeneous catalysts for cycloaddition reaction.