Oxidative Hydrolysis of Cellobiose to Glucose

Abstract  

Cellobiose hydrolysis into glucose was chosen as a model system for cellulose breakdown to investigate glycosidic bond cleavage. The hydrolysis was enhanced by increased acidity in an inert gas medium, while air-assisted hydrolysis with a neutral solution achieved over 70% glucose yield. Hydrogen peroxide, as a stronger oxidant than air, converted cellobiose to carboxyl compounds, which lowered the glucose selectivity. At 150 °C, the selectivity from cellobiose to glucose was very low on porous γ-Al₂O₃ supported catalysts, even lower than without a catalyst. When the active metals were prepared on non-porous supports such as spherical alumina (α phase), the overall yield of glucose was dramatically improved at 120 °C. Similar improvements were obtained for another disaccharide model, sucrose, which achieved greater than 90% sucrose conversion with selectivity in excess of 90% at 80 °C.