Acid-mediated production of hydroxymethylfurfural from raw plant biomass with high inulin in an ionic liquid

Chicory roots were introduced for the direct synthesis of hydroxymethylfurfural (HMF), a platform chemical using HCl and the ionic liquid, 1-octyl-3-methylimidazolium chloride ([OMIM]Cl). HCl played an important role in the hydrolysis of chicory sugar polymers. The highest inulin conversion (60.6 ± 4.4% dwt) occurred with 0.3 M HCl. Increasing HCl concentration up to 1.5 M did not improve inulin conversion. Negligible inulin hydrolysis was found in the absence of HCl. The highest HMF yield (50.9 ± 5.4% dwt) was obtained in a reaction mixture containing 50% of the reaction solvent ([OMIM]Cl + ethyl acetate) and 50% of the root extract prepared in 0.3 M HCl solution. Increasing the HCl concentration resulted in a decrease in HMF yield. The addition of CrCl2 catalyst decreased HMF yields by an average of 25%. The highest productivity of HMF was achieved in the reaction mixture containing 50% reaction solvent (an admix of 80% [OMIM]Cl + 20% ethyl acetate) and 50% chicory root extract prepared from 20% (w/v) root biomass concentration.