Reaction mechanism of sugar derivatives in subcritical and supercritical water

For development of a process of recovering chemicals from biomass by using supercritical water as a reactor solvent, a mechanistic study has been conducted for the reaction of D-glucose and D-fructose in sub- and supercritical water. A series of experiments was conducted over wide ranges of reaction temperature (350 similar to 450 degreesC), pressure (25 similar to 40 MPa), and reaction times (0.02 similar to1.02 s) with a flow type rector. As a result, we found that the contribution of retro-aldol condensation became predminonant at higher temperatures, while that of dehydration reaction formation of furan derivatives) became significant at lower temperatures. In supercritical condition, retro-aldol condensation became essential for reducing reaction pressure, against the dehydration reaction.