Immobilization of ionic liquid on hybrid MCM-41 system for the chemical fixation of carbon dioxide on cyclic carbonate

Ionic liquids (ILs) on ordered mesoporous materials are very useful and effective for chemical fixations of CO2, which is a vital step in the production of cyclic carbonates. In the present study, generation of ionic liquids on chloropropyl containing MCM-41 (CP-MS41) via the immobilization of trialkylamines (R4Cl-MS41) was attempted. The first step was a simple condensation under basic conditions yielding CP-MS41 leading sequentially to R4Cl-MS41. A wide variety of CP-MS41 by manipulating the TEOS to 3-chloropropyltriethoxysilane (ClPTES) ratios were synthesized and characterized by a number of physico-chemical measurements such as XRD, BET, FT-IR, CP 13C, 29Si MAS-NMR and TG/DTG. 29Si MAS-NMR and FT-IR spectra reveal adduct formation of ionic liquids with the chloropropyl groups tethered to the silica surface. The amount of ClPTES incorporated in the silica framework increased with the ClPTES concentration in the synthesis gel, while the ordering of the mesoporous structure gradually decreased. The activities of immobilized ionic liquids (IILs) show the reusability and superior activity of IILs having amines with lower alkyl chain lengths.