Fructose Transformations in Ethanol using Carbon Supported Polyoxometalate Acidic Solids for 5‐Ethoxymethylfurfural Production

A series of carbon supported polyoxometalates have been prepared and studied as acid catalysts for the fructose dehydration. The catalytic supports, microporous activated carbon (AC, SBET=1190 m2/g) and high surface area graphite (HSAG, SBET=400 m2/g), were loaded with 15 wt% of polyoxometalates: phosphotungstic acid (TPA) or tungstosilicic acid (STA). The four resulting catalysts were tested in the fructose reaction at moderate temperature 140 °C, using water and ethanol solvents. Catalytic properties have been compared with those of an acidic resin, Amberlyst 15. As relevant findings the specific interactions of carbon supports and polyoxometalates let the inhibition of active phase lixiviation. An improved catalyst (STA‐HSAG) in terms of selectivity to valuable products (ethoxymethylfurfural and ethyl levulinate) and high specific catalytic activity using ethanol as solvent has been developed. This catalyst can be reused after regeneration by washing with organic solvents. On the path: A new acid catalyst is developed by anchoring a polymetalate to basal surfaces of graphite, with applicability for the transformation in ethanol solvent of fructose into ethoxymethylfurfural and ethyl levulinate.