Insights into Hydrothermal Decomposition of Cellobiose in Gamma-Valerolactone/Water Mixtures

This study provides new insights into the solvent effect of gamma-valerolactone (GVL) during hydrothermal decomposition of cellobiose at 150-200 degrees C in GVL/water mixtures. It was found that GVL addition (even at a small concentration of 0.03%) strongly suppresses the isomerization reaction, which is the dominant primary reaction of cellobiose decomposition in water. In GVL/water mixtures, the selectivity of primary hydrolysis reaction rapidly increases from similar to 10% to similar to 80% when the GVL concentration increases from 0 to 10%. Due to the enhanced hydrolysis reaction in GVL/water mixtures, this study achieves a maximal glucose yield of similar to 66%, which is the highest glucose yield reported so far from cellobiose decomposition under acid-free conditions. The results clearly demonstrate that, in comparison to water only, GVL/water solvent is a promising reaction medium for glucose recovery under acid-free conditions, obviously due to the significantly enhanced hydrolysis reaction and suppressed isomerization reaction in GVL/water mixtures.