Ionic liquid confined spaces controlled catalytic CO2 cycloaddition of epoxides in BMIm.ZnCl3 and its supported ionic liquid phases

Chemical fixation of CO2 to epoxides is an atom-economic and environment-benign approach generate cyclic carbonates. Herein, we report efficient activation the different aromatic aliphatic at ambient reaction conditions. Our n-butyl-3-methylimidazulim trichlorozincate (BMIm.ZnCl3) ionic liquid presents higher activity with 56–95% conversion for from atmospheric pressure 5 bar 40 °C. Small sized showed selectivity carbonate as compared bulky ones suggesting that large epoxide substrates restricted diffusion into confined spaces BMIm.ZnCl3 IL, which limited access reactants catalytic active sites. By supporting IL on simple commercial SiO2, SILP-ZnCl3 catalyst boosted maximum yield (99%) carbonates under 10 100 This performance could be attributed formation IL-cages onto SiO2 enhances local charge density modulates orientation near surface assist substantial transfer, leading polarization specific adsorption ions. The exemplifies a rare mechanism, supplemented by ex-situ ESI-MS analysis, in 'O' strongly H-bonded C2-H imidazolium cation, while ZnCl3 anion acts nucleophile facilitate ring opening without its dissociation chloride ZnCl2, contrasting previous reports.