Conversion of Monosaccharides into Aromatic Compounds over a Charcoal-supported Platinum Catalyst in High-temperature Water

Abstract

In the present study, we conducted the conversion of monosaccharides to aromatic compounds over a charcoal-supported platinum catalyst in high-temperature water and investigated the effects of the reaction conditions and monosaccharide type on the yields of aromatic compounds. Conversion of glucose (C6), xylose (C5), and glyceraldehyde (C3) at 573 K gave total yields of aromatic compounds of glucose (3.1 %) > xylose (2.4 %) > glyceraldehyde (2.1 %) in order of decreasing carbon number. We concluded that these low yields were the result of slow carbon–carbon bond formation, which is required for formation of aromatic compounds from these monosaccharides. In contrast, conversion of the monosaccharides at 673 K gave comparable yields of aromatic compounds at around 4 %, indicating that carbon number had no effect at higher temperature. To investigate the reaction pathway from monosaccharides to aromatic compounds, we also converted various monosaccharide derivatives. The yields of aromatic compounds from sugar alcohols, which do not have formyl groups, were much lower than those from the parent monosaccharides, indicating that the formyl groups in the monosaccharides are essential for the formation of aromatic compounds.