Obtaining xylitol by hydrolysis-hydrogenation of liquors derived from sugarcane bagasse

Abstract

This work presents the study of heterogeneous catalysis of sugarcane bagasse hydrothermal treatment spent liquors using a sulfonated resin. Besides, results were compared with those obtained by a conventional route using sulfuric acid as a homogeneous catalyst. Heterogeneous catalysis is suitable for the hydrolysis of sugarcane bagasse hydrothermal liquors under mild conditions (100°C and 6 h). The obtained maximum xylose yield was 82% due to furfural formation, which causes a xylose selectivity drop. The hydrogenation of this xylose-rich liquor at 100 °C and 3 MPa of hydrogen pressure employing a supported Ni/γ-Al2O3 produced the total conversion of xylose with a selectivity towards xylitol of 100% by using a catalyst to xylose mass ratio of 0.5. Heterogeneous catalysis in a two-step route (hydrolysis and hydrogenation) constitutes an outstanding alternative to producing xylitol from sugarcane bagasse hydrothermal spent liquors since materials can be easily separated and reused in several reaction cycles.

Keywords

• sugarcane bagasse
• hydrolysis
• hydrogenation
• xylose
• xylitol