Dehydration of C6-monosaccharides to 5-hydroxymethylfurfural in dimethyl sulfoxide using sulfonic acid heterogeneous catalysts

Abstract

The use of sulfonic acid-functionalized heterogeneous catalysts in conjunction with the use of dimethyl sulfoxide (DMSO) as solvent in the catalytic dehydration of C6 monosaccharides into 5-hydroxymethylfurfural (HMF) has been shown as an interesting alternative route for the production of this platform molecule. Amberlyst-70 was selected as the most active catalyst, ascribing its higher catalytic performance to its higher concentration of sulfonic acid sites, as compared with the rest of the evaluated catalysts. Starting from fructose, the use of Amberlyst-70 led to 93 mol% yield to HMF after just 1h. For glucose, a much more difficult reaction, reaction conditions (time, temperature and catalyst loading) where optimized for Amberlyst-70 via response surface methodology leading to a maximum HMF yield of 33 mol% at 147ºC, 23 wt% catalyst loading based on glucose loading and 24h. Noticeably, DMSO promotes the dehydration of glucose into anhydroglucose, which acts as a reservoir of substrate facilitating the production of HMF, since it reduces the extent of side-reactions. A study of catalyst¿s reuse, without regeneration treatment, evidenced a gradual decay in catalytic activity, though not very significant.