Work

Obtaining bio-additives using free and supported ionic liquids: the case study of furfural acetalization with either ethylene glycol or glycerol

Year: 2026

Type: article

Abstract: This work presents the results of the acetalization reaction between furfural and polyols (ethylene glycol or glycerol), employing an ionic liquid, 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate, [C4SO3Hmim][HSO4], as a catalyst. Two series of catalysts were prepared and characterized. These catalysts were supported on silica gel 60 and on SBA-15 mesoporous silica, with variable IL loading (10 - 50 wt%). All of them showed good activity in the formation of the desired cyclic ethers, 2-(furan-2-yl)-1,3-dioxolane and the cis-trans (2-(furan-2-yl)-1,3-dioxolan-4-yl) methanol and cis-trans (2-(furan-2-yl)-1,3-dioxan-5-ol isomers. Furthermore, the activity exhibited by some of these catalysts surpassed that of the unsupported IL. The catalyst SBAIL30 was the most active, with a cyclic acetal yield of 51%. This particular sample is characterized by its elevated number of strong acid sites, a property that is supported by the results of the XPS analysis. These strong acid sites are believed to be derived from the presence of sulfonic groups within the IL. The use of heterogeneous catalysts had a significantly impact on the stereochemistry of the reaction. While the 6-membered ring is the most thermodynamically stable product, SILx and SBAILx catalysts were found to favor the formation of the 5-membered ring in a higher proportion than that found in the reaction performed in the absence of catalyst.

Source: Biomass and Bioenergy

DOI: 10.1016/j.biombioe.2026.109743