Selective Hydrolysis of Cellulose and Polysaccharides into Sugars by Catalytic Hydrothermal Method Using Sulfonated Activated-carbon

Mildly hydrothermal reaction using solid acid catalysts for cellulose hydrolysis into glucose has potential abilities to be one of the key technologies for a future sustainable society using cellulose biomass. Among the solid acid catalysts tested, such as H-form zeolite catalysts and sulfated and sulfonated catalysts, sulfonated activated-carbon (AC-SO3H) catalyst showed remarkably high yield of glucose in the hydrolysis of cellulose with beta-1,4-glycosidic bonds under hydrothermal conditions at temperatures around 423 K. The AC-SO3H catalyst with hydrothermal pre-treatment had excellent catalytic properties attributed to the high hydrothermal stability and the strong acid sites of the sulfo functional groups and the activated carbon surfaces for polysaccharide adsorption. A bifunctional sulfonated activated-carbon supported platinum (Pt/AC-SO3H) was prepared by impregnation of platinum on activated carbon (AC) and sulfonation of the prepared Pt/AC. Gluconic acid was produced from polysaccharides, such as starch and cellobiose, in water at 393 K under air by a one-pot process using the Pt/AC-SO3H catalyst.