Molecular Moieties Having Pyrene and Carboxylic Acid for the Hydrolysis of Cellulose

Hydrolysis of cellulose to glucose is a challenging and crucial step in the field of biomass conversion to fuels and value-added chemicals. Despite the abundance of cellulose, its recalcitrant crystalline structure presents a challenge for its depolymerization to smaller molecules. Conventional heterogeneous catalysts are unable to access glycosidic bonds in cellulose, necessitating cost-consuming pretreatments such as ball-milling. Here, we report a novel approach based on heterogeneous molecular moieties that adsorb on the cellulose surface and hydrolyze cellulose. Three compounds featuring an adsorption domain in the form of a pyrene moiety and vicinal carboxylic acids as an active site were synthesized and tested. By harnessing the cellulose-binding properties of pyrene and the weak acidic functional groups for hydrolysis, these compounds demonstrated enhanced rates of hydrolysis without the need for pretreatment. Glucose yield was increased at a mild temperature of 150 °C in water in the presence of molecular compounds. This work shows a new design idea that can overcome the issues associated with solid acid catalysts for the hydrolysis of crystalline cellulose.