title: Promotion or suppression of glucose isomerization in subcritical aqueous straight- and branched-chain alcohols.
abstract: The influence of water-miscible alcohols (methanol, 1-propanol, 2-propanol, and t-butyl alcohol) on the isomerization of glucose to fructose and mannose was investigated under subcritical aqueous conditions (180-200 °C). Primary and secondary alcohols promoted the conversion and isomerization of glucose to afford fructose and mannose with high and low selectivity, respectively. On the other hand, the decomposition (side-reaction) of glucose was suppressed in the presence of the primary and secondary alcohols compared with that in subcritical water. The yield of fructose increased with increasing concentration of the primary and secondary alcohols, and the species of the primary and secondary alcohols tested had little effect on the isomerization behavior of glucose. In contrast, the isomerization of glucose was suppressed in subcritical aqueous t-butyl alcohol. Both the conversion of glucose and the yield of fructose decreased with increasing concentration of t-butyl alcohol. In addition, mannose was not detected in reactions using subcritical aqueous t-butyl alcohol.
authors.affiliation: a Division of Food Science and Biotechnology, Graduate School of Agriculture , Kyoto University , Kyoto , Japan.
authors.forename: Da-Ming
authors.initials: DM
authors.lastname: Gao
authors.forename: Takashi
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Shuji
authors.initials: S
authors.lastname: Adachi
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D005947:Glucose / Q000737:chemistry*; D007536:Isomerism; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D000438:Alcohols; D014867:Water; D005947:Glucose
keywords: fructose; glucose; isomerization; mannose; subcritical aqueous ethanol