Dihydroxy functionalized binuclear carbonate based poly(ionic liquid)s for highly efficient conversion of low-concentration CO2 into cyclic carbonate

The elimination of carbon dioxide (CO 2 ) from the industrial post-combustion dilute CO 2 has been a hot issue and the selective conversion of CO 2 from the exhaust gas stream still remains a challenge. Herein, dihydroxy functionalized binuclear carbonate based poly(ionic liquid)s (HB-PILs) were prepared for conversion of low-concentration CO 2 from the dilute CO 2 (15 vol% CO 2 + 85 vol% N 2 ) into cyclic carbonate. Using epichlorohydrin as a probe substrate, the obtained HB-PILs exhibited excellent catalytic performance for the CO 2 cycloaddition reaction. Under optimized process parameters (100 ℃, 2 MPa and 4 h), the highest yield (95 %) of chloropropene carbonate (CPC) was obtained, which was comparable to the previous reported results. Moreover, the synergetic effect between the activation of epoxides by dihydroxyl groups and the adsorption of CO 2 by basic CO 3 2- ions was studied through the theoretical calculations. DFT results indicated that CO 3 2- served as the nucleophilic site, working synergistically with hydrogen bond donors to facilitate the ring-opening of epichlorohydrin (ECH). Additionally, CO 3 2- functioned as the basic site to activate CO 2 . This study will provide a promising solution for mitigating global climate change and advancing the green chemistry of CO 2 utilization from dilute CO 2 .