SO3H-functionalized ionic liquid: Efficient catalyst for bagasse liquefaction

Acidic ionic liquids were proven to be efficient bagasse liquefaction catalysts for the first time. More than 96.1% bagasse was liquefied under the optimized conditions, where 50.6% of it was selectively converted to low-boiling biochemicals. Furthermore, the catalytic activity and product distribution selectivity depend greatly on the acidic strength of IL due to the catalytic liquefaction competing efficiently with hydrolysis mechanism. [Display omitted] ► Acidic ILs as catalysts in the liquefaction of bagasse in hot compressed water. ► 96.1% Liquefaction and 50.6% selectivity for low-boiling chemicals obtained at 543K. ► Catalytic activities and selectivity depend greatly on the acidic strength of the ILs. ► ILs catalytic liquefaction competed with hydrolysis processes. ► A possible liquefaction mechanism was proposed. Liquefaction is a process for the production of biofuel or value-added biochemicals from non-food biomass. SO3H-, COOH-functionalized and HSO4-paired imidazolium ionic liquids were shown to be efficient catalysts for bagasse liquefaction in hot compressed water. Using SO3H-functionalized ionic liquid, 96.1% of bagasse was liquefied and 50.6% was selectively converted to low-boiling biochemicals at 543K. The degree of liquefaction and selectivity for low-boiling products increased and the average molecular weight of the tetrahydrofuran soluble products decreased with increasing acidic strength of ionic liquids. Analysis of products and comparative characterization of raw materials and residues suggested that both catalytic liquefaction and hydrolysis processes contribute to the high conversion of bagasse. A possible liquefaction mechanism based on the generation of 3-cyclohexyl-1-propanol, one of the main products, is proposed.