Heteropoly Acid-Based Ionic Liquid Catalyzes Cellulose into Levulinic Acid in a Bi-Phase Solvent System

Graphical Three kinds of heteropoly acid-based ionic liquids with different Hammett acidity were prepared for the catalytic conversion of cellulose to levulinic acid, and the effects of different solvent systems on the catalytic reactions were investigated. The results showed that higher Hammett acidity was beneficial to increase the yield of levulinic acid, and GVL/H 2 O bi-phase solvent system was helpful to extract the product to the organic phase and promote the formation of levulinic acid. Levulinic acid is an important chemical intermediate, which has many applications in organic synthesis, industry, agriculture, and medicine. In this word, three kinds of heteropoly acid based ionic liquids ([IMPS]H 2 PW 12 O 40 、[PyPS] H 2 PW 12 O 40 [TEAPS] H 2 PW 12 O 40) were used to catalyze the one-pot conversion of cellulose to levulinic acid. [IMPS]H 2 PW 12 O 40 has the highest catalytic activity due to its strong Hammett acidity ( H 0 ). In addition, the effect of biphasic solvent systems on the conversion of cellulose to levulinic acid was also studied. The results showed that the GVL/H 2 O system could effectively promote the conversion of cellulose and increase the yield of levulinic acid. The yield of levulinic acid could reach 52.6% and the conversion rate of cellulose was 91.2% at 180 °C for 180 min under the GVL/H 2 O volume ratio of 1:1 with [IMPS]H 2 PW 12 O 40 as a catalyst at 1 Mpa N 2 and cellulose as raw material. And [IMPS]H 2 PW 12 O 40 can be recycled up to five times without significant performance loss. This study provides a promising method for efficiently converting cellulose and other biomass resources to levulinic acid extraction.