Silicon semiconductor-assisted Bronsted acid-catalyzed dehydration: Highly selective synthesis of 5-hydroxymethylfurfural from fructose under visible light irradiation

Semiconductor materials are used to promote Bronsted acid-catalyzed dehydration of fructose to 5-hydroxymethylfurfural (HMF) under visible light irradiation. In the proposed reaction system the semiconductors convert light to heat, transferring chemical energy to the substrates. We found that silicon was a more suitable semiconductor for the conversion of fructose to HMF compared with alpha-Fe2O3, WO3, and TiO2. Remarkably, a silicon semiconductor coated with silanol groups (Si-OH) affords HMF in almost quantitative yield (97%) even at 80 degrees C. This result suggests that the Si-OH catalyst provides energy selectively to the starting material fructose and not to desired product HMF, preventing side-reactions. (C) 2013 Elsevier B.V. All rights reserved.