Hydrolysis of Anhydrosugars over a Solid Acid Catalyst for Saccharification of Cellulose via Pyrolysis

Glucose is a key compound for future biomass-based energy and chemical industry. An availability of glucose from abundant lignocellulosic biomass is limited because of a slow reaction rate and costly feed materials in a conventional enzymatic hydrolysis of cellulose. The present work investigated the production of glucose with hydrolysis of anhydrosugars produced by cellulose pyrolysis that is a fast reaction with no requirement for other chemicals to feed. A commercially available solid acid was employed as the hydrolysis catalyst for enabling a direct use of glucose aqueous solution without posttreatment such as separation. The experiments using a model anhydrosugar, levoglucosan (LGA), as feedstock revealed a selective activity of the catalyst to produce glucose even at the high concentration of 2.7 M and the catalytic stability in 15 h run of the reaction using a continuous flow reactor. The catalyst worked for the reaction with a cellulose-derived bio-oil as the feedstock to selectively produce glucose mainly from LGA. However, the activity gradually decreased due to deposition of carbonaceous materials from compounds other than LGA over the catalyst, indicating a necessity for eliminating those compounds before the hydrolysis.