Modeling xylan solubilization during autohydrolysis of sugar maple wood meal: Reaction kinetics

The objective of this work was to study the kinetics of hemicelluloses extraction during hydrothermal pretreatment of sugar maple wood meal. Pretreatment was conducted in a batch reactor at 145-185°C with reaction times up to 8 h and with liquor to solid ratio of 20:1. Under these conditions, hemicelluloses were selectively solubilized and little degradation (approximately 6-9% of the initial amount) of cellulose and lignin was observed. A kinetic model was developed. It was supposed that there are no diffusion limitations and that the reaction rate constants have first-order kinetics with Arrhenius-type temperature dependence. The model proposes the formation of xylose directly from wood xylan as well as from xylooligomers formed in the liquid phase by the hydrolysis of xylan. The model is able to correlate satisfactorily experimentally measured yields of residual xylan, xylooligomers, xylose, and furfural obtained during the pretreatment.