Sulphonic Acid-Functionalized Polymeric Ionic Liquids Catalyzed Conversion of Carbohydrates into Levulinic Acid in One-Pot Reaction

Graphical Polymeric ionic liquids for conversion of cellulose into levulinic acid : A high levulinic acid yield of 79.4 % was achieved when used cellulose as substrates and sulphonic acid-functionalized polymeric ionic liquids as catalyst. Sulphonic acid-functionalized polymeric ionic liquids (PILs) were synthesized and applied into catalytic conversion of cellulose into levulinic acid (LA). The structure, thermal stability, and Hammett acidity function (H 0 ) of PILs were characterized and all were more thermostable than those of small-molecular ionic liquids (IL). At the optimum reaction conditions, the LA yield was maximized to 79.4 % by catalyst [Pim]CH 3 SO 3 . More importantly, catalyst [Pim]CH 3 SO 3 performed well in other biomass conversion, such as cellobiose, starch and rice husk. The product LA can be easily extracted by methyl isobutyl ketone from the reaction mixture. The PILs with high catalytic activity were easily recycled with an LA yield up to 68.9 % even after five cycles. These sufficient PILs will offer new approaches for transforming biomass to platform chemicals.