Complete chemical hydrolysis of cellulose into fermentable sugars via ionic liquids and antisolvent pretreatments

This work describes a relatively simple methodology for efficiently deconstructing cellulose into monomeric glucose, which is more easily transformed into a variety of platform molecules for the production of chemicals and fuels. The approach undertaken here first involves the dissolution of cellulose in an ionic liquid (IL), followed by a second reconstruction step aided by an antisolvent. The regenerated cellulose exhibited strong structural and morphological changes, as revealed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses. These changes dramatically affect the hydrolytic reactivity of the cellulose with dilute mineral acids. As a consequence, the glucose yield obtained from the deconstructed-reconstructed cellulose was substantially higher than that achieved via hydrolysis of the starting cellulose. Factors that affect the hydrolysis reaction include the type of cellulose substrate, the type of IL used in the pretreatment and the type of acid used in the hydrolysis step. The best results were obtained by treating the cellulose with IL and using phosphotungstic acid (0.067 mol/L) as a catalyst at 413 K. Under these conditions, the conversion of cellulose was almost complete (> 99 %), with a glucose yield of 87 % after only 5 h of reaction.Comunidad de Madrid (Spain) S2009/ENE-1743CSIC (Spain) 201180E038Peer reviewe