Enhanced cycloaddition of CO2 to epichlorohydrin over zeolitic imidazolate frameworks with mixed linkers under solventless and co-catalyst-free condition.

ga1 • ZIF-8-90 showed significantly improved selectivity (up to 99%) compared to ZIF-8. • ZIF-8-90 exhibited better catalytic ability with lower cost than ZIF-90. • A higher TOF of ZIF-8-90 was obtained than those of most of other ZIFs. • ZIF-8-90 displayed enhanced framework stability with good cycling. An efficient dual-ligand zeolitic imidazolate framework ZIF-8-90 was fabricated for the synthesis of five-membered cyclic carbonate from CO 2 and epichlorohydrin (ECH) in the absence of co-catalysts and solvents. The effects of various reaction parameters were studied. The dual-ligand ZIF-8-90 showed very high selectivity (up to 99%). ZIF-8-90 exhibited better catalytic ability with lower cost than ZIF-90 and enhanced framework stability with significantly improved selectivity compared to ZIF-8. Moreover, the catalyst has been successfully reused for three cycles with negligible decrease in the catalytic activity. A plausible mechanism for the ZIF-8-90 catalyzed ECH−CO 2 cycloaddition under solvent-free and co-catalyst-free has been proposed. [ABSTRACT FROM AUTHOR]