Kinetics of xylan hydrolysis using an acetic and formic acid-based organosolv pretreatment

This study aimed at understanding the kinetics of xylan hydrolysis during an acetic and formic acid-based organosolv pretreatment of wheat straw, and determining the factors that govern xylose degradation. The reaction mechanism and kinetics were investigated, covering the reaction conditions: 95–105 °C, 1–4 h, with a fixed acetic acid/formic acid/water ratio. The experimental data were successfully fitted to a first-order monophasic model which suggested that xylan dissolution occurred in three stages and tended towards a limit value dependent on the temperature. Xylose oligomers were included in the model as reaction intermediates and their hydrolysis into xylose has been associated to the rate determining step. Furfural production has been slowed down with the optimization of the combined effect of process temperature and time, while maintaining a good recovery of xylan, a sufficient dissolution of lignin (more than 60% and 80% respectively) and a very low degradation rate of cellulose. © 2021 Elsevier Ltd