Dehydration of pentose to furfural catalyzed by formic acid – Kinetics and application to real biomass hydrolysates

Abstract

This paper investigates the kinetics of xylose and real biomass hydrolysate conversion into furfural catalyzed by formic acid through batch experiments. The kinetic experiments were conducted across temperatures ranging from 140 °C to 200 °C using various concentrations of formic acid solution (5–20 wt%) and xylose concentrations varying from 0.062 mol/L to 0.2 mol/L. Three common reaction mechanisms were examined, and their results were compared with previous studies. Among these mechanisms, the model 3 which incorporated the formation of an intermediate followed by its cross-polymerization with furfural, exhibited the most favorable performance, with coefficient of determination values surpassing 95 %. Furthermore, the study demonstrated the reliability of kinetic modeling for raw biomass hydrolysate, with minimal deviation between experimental and predicted values. Optimal conditions resulted in the highest furfural yield of 58 % with a xylose concentration of 0.062 mol/L. Similarly, under identical conditions, birchwood and oat spelts xylans yielded maximum furfural yields of 63 % and 51 %, respectively. Moreover, hydrolysates from oil palm empty fruit bunch and fir wood exhibited the best furfural yields of 62 % and 57 %, respectively, along with an equal 5-HMF yield of 32 %. The results indicated that the developed model exhibited a high level of accuracy in predicting maximum yields with a relative deviation of less than 10 %.