Catalytic behaviour of TiO2-ZrO2 binary oxide synthesized by sol-gel process for glucose conversion to 5-hydroxymethylfurfural

The catalytic application of as-synthesized TiO2-ZrO2 binary oxides was examined for the conversion of glucose to produce 5-hydroxymethylfurfural (HMF). Highest HMF yield (74%) at glucose concentration of 5 wt% was obtained with TiO2-ZrO2 (1/1) and Amberlyst 70 catalyst system in a water-THF biphasic reaction system. Notably, a much higher HMF yield (86%) was achieved when the organic phase of the biphasic system was replaced with dioxane. The increased product yield may be ascribed to the role of dioxane as an aqueous phase modifier that stabilizes HMF in the reactive phase as well as promotes partitioning of HMF into the extractive layer. Furthermore, the combined catalyst and biphasic solvent systems were also effective for the conversion of glucose polymers to HMF.