Catalytic production of sugars and lignin from agricultural residues using dilute sulfuric acid in γ-valerolactone

Highlights: • Conversion of agricultural residues to sugars and lignin using sulfuric acid. • The physicochemical properties of the biomass affect the sugars yield. • Process variables such as heating ramp have a significant effect on sugars yield. The fractionation of sugarcane bagasse, plantain peel and brewer's spent barley to glucose, xylose and lignin was studied using 0.50 and 0.05 wt% H₂SO₄ as catalyst in a mixture of 80:20 wt% GVL:H₂O. We obtained glucose and xylose cumulative yields with up to 90, 94 and 88% for sugarcane bagasse, plantain peel and brewer's spent barley, respectively. We studied the effects of the reaction conditions and physicochemical properties of the agricultural residues on the production of sugars. The production of sugars depends on the physicochemical properties of each residue. The lignin content, biomass crystallinity and ashes composition have the strongest effects on the production of sugars. The lignin can affect the accessibility to hemicellulose and cellulose during the reaction reducing the amount of sugars that can be obtained from the residue. The ashes present in the biomass may have alkaline species that can neutralize the acid catalyst reducing the rate of sugar production for a given acid concentration. The sugar production decreases as the biomass crystallinity increases.