Synthesis and characterization of ionic liquid-functionalized alumino-silicate MCM-41 hybrid mesoporous materials

Abstract

Ionic liquid-functionalized alumino-silicate MCM-41 hybrid mesoporous materials have been synthesized with two-step approach, by means of in situ skeleton doping with aluminium and post surface grafting with N-methylimidazole ionic liquid groups. The samples were characterized by X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), N2 adsorption–desorption, Fourier transform infrared (FTIR) spectra, 27Al and 13C MAS NMR spectra and temperature-programmed desorption (TPD) of NH3. The results indicated that the bifunctionalized MCM-41 possessed ordered mesostructure. Aluminium was efficiently introduced into the framework of the mesostructure, generating Lewis and Brönsted acid sites. N-methylimidazole ionic liquid groups were covalently grafted onto the surface of mesoporous materials. The as-synthesized bifunctional MCM-41 showed good catalytic performance in the coupling reaction of CO2 and propylene oxide.