Deep processing of hemicelluloses to high value-added products and hydrolysis of arabinogalactan on the Al-Zr-SBA-15 solid catalysts

Abstract

Catalysts were developed for the depolymerization of plant polysaccharides based on mesoporous mesostructured silica SBA-15 doped with Al and Zr oxides to enhance acidity. The catalysts were studied by a set of physicochemical methods (X-ray diffraction (XRD), low-temperature adsorption—desorption of N₂, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), magic angle spinning (MAS) NMR spectroscopy, IR spectroscopy, and point of zero charge (pzc) determination, as well as tested during arabinogalactan depolymerization to high value-added products. The catalyst acidity is the parameter predetermining its activity in the depolymerization. The acidity of the catalysts with the combined doping of SBA-15 with Al and Zr oxides is higher than the one with the individual doping. The maximum yield of monomeric products on 2.5Al-5Zr-SBA-15 is 61.2 wt.% (4 h). Arabinose (4.6 wt.%), galactose (45.2 wt.%), furfural (3.0 wt.%), and 5-hydroxymethylfurfural (16.2 wt.%) are observed among the major products.