Multifunctional Task‐Specific Ionic Liquids on Solid Supports: A Dual Function as Brønsted Catalyst and Solid Solvent for HMF Production from Fructose

A novel supported ionic liquid phase (SILP) incorporating both dimethylsulfoxide (DMSO) and sulfonic acid (SO3H) moieties is reported. This SILP significantly enhances the gram-scale dehydration of fructose-to HMF when utilized with deep eutectic solvents (DES). The SILP, acting as a solid solvent, effectively mimics the beneficial role of DMSO, leading to improved HMF yields and reduced humin formation.

For the first time, supported ionic liquid polymers (SILPs) incorporating sulfone and dimethyl sulfoxide units are synthesized and tested as bifunctional heterogeneous materials in the valorization of biomass-derived sugars (fructose and glucose). These catalysts exhibit remarkable efficiency in fructose dehydration, yielding 5-hydroxymethylfurfural (HMF) at gram scale. The optimal ratio of sulfone to dimethyl sulfoxide groups is determined to be critical for reaction selectivity. The synergistic effect of these functional groups significantly enhanced HMF production at gram scale, outperforming conventional homogeneous acid catalysts like HCl in both efficiency and recyclability. Moreover, the system demonstrates exceptional performance when using deep eutectic solvents, highlighting its versatility in HMF synthesis. The selected material is also active in the synthesis of HMF or levulinic acid from glucose in a biphasic system. DFT calculations elucidated the reaction mechanism, revealing the cooperative role of the dimethyl sulfoxide cosolvent and the Brønsted acid sites within the SILPs.

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