Hydrolysis of eucalyptus wood chips under hot compressed water in the presence of sulfonated carbon-based catalysts

Hydrolysis of lignocellulosic biomass to sugars and derivatives is a key step in production of biofuels and commodity chemicals in a biorefinery. In this study, catalytic hydrolysis of eucalyptus chips with solid sulfonated carbon-based catalysts prepared from three different carbon precursors (sucrose, glucose, and xylose) was studied under hot-compressed water at 150-250 degrees C with reaction time of 1-10 min. Increasing temperature up to 200 degrees C led to higher sugar yields from cellulose and hemicellulose while further increase in temperature caused higher formation of sugar degradation by-products. Sulfonated-sucrose (SO3 H-Suc) showed the greatest performance on sugar production compared to other catalysts with less formation of furans and anhydroglucose; its high catalytic activity was related to its high acid site density as proven by NH3 -TPD measurement. Size reduction and chemical pretreatment of the biomass were found to enhance the hydrolysis yield and reaction selectivity. The highest sugar yield of 40.7% comprising glucose, fructose, and xylose was achieved using 5% (w/w) SO3 H-Suc at 200 degrees C for 5 min with milled biomass (60-100 mu m) pretreated by alkaline oxidation. The work provides an alternative catalytic process for hydrolysis of lignocellulose in biomass industry. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.