Preparation Of Catalyst Supported Acid Ionic Liquids And Its Application In Cycloaddition Reaction

Ionic liquids are salts at room temperature which are composed of anions andcations. They are important solvents and catalysts in modern chemical industry. In thecycloaddition reaction, they performed highly catalytic activity. The cycloadditionreaction is a typical green chemical and atom economy reaction, and one of the mainmethods to produce carbonates. But the traditional ionic liquids have manyshortcomings, e.g. the high usage, the high price, and inconvenience of reuse.Developing new kinds of catalysts supported ionic liquids have being received moreand more attention.In this paper, polyethylene glycol （PEG） was different composition was used as apolymer support to load ionic liquids by anions methods. The catalyst structures wereconfirmed by FT-IR, EA and13C NMR, etc. The PEG supported ionic liquids wereused as catalysts in the coupling reaction of propylene oxide （PO） and CO2. It wasfound that PEG₄₀₀-MIM-HSO₄was the most efficient catalyst. The optimal conditionwas that:1g PO,6mmol%catalyst,3.0MPa,120℃,4h. The conversion of PO was95%and the selectivity of propylene carbonate （PC） reached to as high as99%. ThePEG-supported ionic liquids had good cycle performance.The inorganic silica supported acidic ionic liquids were also synthesized. Thematerial structures were confirmed by BET, FT-IR, EA and13C NMR, etc. In thecycloaddition reaction, the result was found that, the conversion of PO was more than95%with all the silica supported ionic liquids as the catalysts, but the selectivity ofPC was lower than that of PEG-supported catalyst. When [Smim]HSO₄was taken asthe catalyst, the selectivity of PC was the highest,90.6%. The catalyst system couldperform highly catalytic activity even under the low pressure （1.0MPa）. The catalystcould be recycled and reused for six times, without any significant loss of catalyticactivity.The mesoporous material SBA-15supported weak acidic ionic liquids weresynthesized. The structures of catalysts were confirmed by XRD, SEM, TEM, BET,FT-IR, EA and13C NMR, etc. SBA-15supported ionic liquids were used as catalystsin the cycloaddition reaction. It was found that, the catalyst SBA-15-OH performed the best catalytic activity. It was ascribed to the uniform hexagonal channels and thehydrogen bonding of the ionic liquid. The conversion of PO was99%and theselectivity of PC was99%. At the while, the catalyst could be recycled and reused forseven times without any significant loss of catalytic activity.