Effect of different halide types on HMF synthesis from kudzu extract in ionic liquid

An eco-beneficial strategy for the production of hydroxymethylfurfural (HMF) was developed using kudzu root extract as a sustainable biomass material and the physicochemical properties of the extract characterized using FESEM, XRD, and FT-IR. The visual image of the kudzu extract and the XRD analysis revealed that the molecular structure of the extract is amorphous and its major composition would be starch. The FT-IR analysis showed 6 characteristic vibration modes contributing to starch and other sugars. The halide ligands of different types significantly affected the synthesis of HMF. The exceptional promotion effect on HMF synthesis was achieved by fluorine ligand of the chromium-based metal catalyst. The most effective stoichiometry ratio of catalyst-to-feed biomass for the synthesis of HMF from kudzu root extract was found at its ratio value of 0.2. The most optimal extraction condition for HMF synthesis from the kudzu extract occurred at 0.3 M HCl. The highest HMF production (34.8 ± 4.8 dwt%) was obtained in the reaction mixture containing 40% (w/v) ionic liquid, 10% (v/v) ethyl acetate, 1% (w/v) halide catalyst, and 50% (v/v) of 0.3 M HCl extract by undergoing the reaction at 130 °C for 12 h.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Kudzu extract was used to synthesize HMF in ionic liquid using metal halide catalysts. ► FESEM and XRD showed that the major feed material for HMF synthesis would be starch. ► Six characteristic vibration modes were identified by FT-IR. ► The HMF synthesis was significantly affected by halide ligands in metal catalysis. ► Optimal extraction and stoichiometry value occurred at 0.3 M HCl and 0.2, respectively.