Applied Surface Science, Vol.428, 218-225, 2018
Functionalized MIL-101 with imidazolium-based ionic liquids for the cycloaddition of CO2 and epoxides under mild condition
A kind of multi-functional sites metal-organic framework (MOF) composite (MIL-101-IMBr) was successfully prepared by post-synthesis modification of MIL-101 with imidazolium-based ionic liquids. The ionic liquids not only functionalize as basic sites but also provide halide anions, which serve as a nucleophile in cycloaddition reaction. The prepared functional MOF materials were characterized by X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, N-2 adsorption-desorption and CO2 temperature programmed desorption. The results of fourier transform infrared spectroscopy and energy dispersive spectroscopy show that the MIL-101-IMBr composite was successfully synthesized. The N-2 adsorption-desorption results clearly demonstrated that the modified composites still preserve high BET surface area and total pore volume. The composite exhibits high catalytic activity for the cycloaddition of CO2 with epoxides under mild and co-catalyst free conditions. The conversion of propylene oxide was 95.8% and the selectivity of cyclic carbonate was 97.6% under 0.8 MPa at 80 degrees C for 4 h. Moreover, the catalyst can be used for at least five times. (C) 2017 Elsevier B.V. All rights reserved.
Keywords:Metal-organic framework;Imidazolium-based ionic liquids;Cycloaddition reaction;Cyclic carbonate