The Catalytic Performance Of Acidic Ionic Liquids And Their Structure-catalytic Activity Relationships

SO3H-functionalized ionic liquids (ILs) are typical strong Bronsted acids, which exhibited great potential for the replacement of conventional homogeneous/heterogeneous acidic catalysts which corrodibility and environmental pollution, such as H2SO4, HF. Because of their excellent acidity and easily to be separated, it has a widely used prospect in the development of green chemistry and the field of cleaning process research. However, SO3H-functionalized ionic liquids haven’t been applied in low polar compound catalytic conversion, the application was limited, and their rational synthesis for specific catalytic reaction have not achieved up to now.In order to expand the application of the SO3H-functinoal ILs, and then assist in their rational synthesis for specific catalytic reaction, it is necessary to explore the effect of acidity and immiscibility of SO3H-functinoal ILs on their catalytic performance. In this parper, ILs were synthesized by using N-methylimidazole,1-(trimethylsilyl)imidazole,1,3-propyl sultone and1,4-Butanesultone as the source, their acidity and immiscibility were characterized by NMR、UV and IC, and then the relationships of acidity and immiscibility with their catalytic performance were investigated.First, the SO3H-functinoal ILs were applied the esterification of glycerol with acetic acid and the synthesis of methacrylate, the results indicated that more than90%of conversion of glycerol was obtained and the ionic liquids can be reused at least five times without any obvious decrease in catalytic activity; and the ILs and the polymerization inhibition can be reused in the same time on the synthesis of methacrylate.We also investigated the catalytic ability of SO3H-functinoal ILs in the liquid-liquid phase acetylation of thiophene, the results revealed that the catalytic performance was dependent on the synergistic effect of the acidity of the ILs and their immiscibility with reactants. This work will further assist in rational synthesis of Brosted-acidic ILs for specific catalytic reaction.