Photoassist-phosphorylated TiO2 as a catalyst for direct formation of 5-(hydroxymethyl)furfural from glucose.

Photo-assisted phosphorylation of an anatase TiO2 catalyst was examined to improve its catalytic performance for the direct production of 5-(hydroxymethyl)furfural (HMF), a versatile chemical platform, from glucose. In phosphorylation based on simple esterification between phosphoric acid and surface OH groups on anatase TiO2 with water-tolerant Lewis acid sites, the density of phosphates immobilized on TiO2 is limited to 2 phosphates nm-2, which limits selective HMF production. Phosphorylation of the TiO2 surface under fluorescent light irradiation increases the surface phosphate density to 50%, which is higher than the conventional limit, thus preventing the adsorption of hydrophilic glucose molecules on TiO2 and resulting in a more selective HMF production over photoassist-phosphorylated TiO2.