One-pot depolymerization of cellulose into glucose and levulinic acid by heteropolyacid ionic liquid catalysis

A series of heteropolyacid (HPA) ionic liquids [C4H6N2(CH2)3SO3H]3−nHnPW12O40 ([MIMPSH]nH3−nPW12O40, n = 1, 2 3, abbreviated as [MIMPSH]nH3−nPW) was used to catalyze one-pot depolymerization of cellulose into glucose. Their performances were much better than those of the previously reported HPAs, such as H3PW12O40, Cs2.5H0.5PW12O40. Besides cellulose, the HPA ionic liquids were able to catalyze the conversion of sucrose and starch into glucose. In addition, one-pot synthesis of levulinic acid (LA) directly from cellulose was realized using these HPA ionic liquid catalysts in a water–methyl isobutyl ketone (MIBK) biphasic system. The separation of the products and catalysts was easy, and the retrieved [MIMPSH]nH3−nPW could be repeatedly used without appreciable loss of performance.