Arabinogalactan hydrolysis and hydrolytic hydrogenation using functionalized carbon materials

Larix Sibirica Arabinogalactan Hydrolysis over Zr-SBA-15; Depolymerization Insight

Arabinogalactan depolymerization over solid Zr-containing SBA-15-based catalyst was studied via HPLC, GPC, and theoretical modeling. Arabinogalactans (AG) are hemicelluloses mainly present in larch wood species, which can be extracted on an industrial scale. The application of solid acid catalysts in the processes of hemicellulose conversion can exclude serious drawbacks such as equipment corrosion, etc. Characterization of 5%Zr-SBA-15 confirmed the successful formation of the mesoporous structure inherent to SBA-15 with fine Zr distribution and strong acidic properties (XRD, XPS, FTIR, pH_pzc). Carrying out the process at 130 °C allowed us to achieve total products yield of up to 59 wt%, which is represented mainly by galactose (51 wt%) and minor (less than 9 wt%) presence of arabinose, furfural, 5-HMF, and levulinic acid. The temperature increases up to 150 °C resulted in a total product yield drop down to 37 wt%, making temperature elevation above 130 °C obsolete. According to the theoretical investigations, arabinogalactan depolymerization follows the primary cleavage of the β(1→3) bonds between the D-galactose units of the main chain, which is also confirmed by GPC.

Combination of Autohydrolysis and Catalytic Hydrolysis of Biomass for the Production of Hemicellulose Oligosaccharides and Sugars

Three different types of biomass sourced from forestry waste (eucalyptus residues), agricultural waste (wheat straw), and energy crop (miscanthus) were used as starting materials to produce hemicellulosic sugars, furans (furfural and hydroxymethylfurfural), and oligosaccharides. A two-step hybrid process was implemented; biomass was first autohydrolysed without any additive to extract hemicelluloses and dissolve it in water. Then, the hydrolysate was treated with a solid acid catalyst, TiO2-WOx, in order to achieve hydrolysis and produce monomeric sugars and furans. This article investigates the role of the biomass type, autohydrolysis experimental conditions, polymerisation degree and composition of hemicelluloses on the performance of the process coupling autohydrolysis and catalytic hydrolysis. The highest global yields of both oligosaccharides and monomeric sugars were obtained from Eucalyptus (37% and 18%, respectively).

Catalytic Upgrading of Biomass-Derived Sugars with Acidic Nanoporous Materials: Structural Role in Carbon-Chain Length Variation

Shifting from petroleum-based resources to inedible biomass for the production of valuable chemicals and fuels is one of the significant aspects in sustainable chemistry for realizing the sustainable development of our society. Various renowned biobased platform molecules, such as 5-hydroxymethylfurfural, furfural, levulinic acid, and lactic acid, are successfully accessible from the transformation of biobased sugars. To achieve the specific reaction routes, heterogeneous nanoporous acidic materials have served as promising catalysts for the conversion of bio-sugars in the past decade. This Review summarizes advances in various nanoporous acidic materials for bio-sugar conversion, in which the number of carbon atoms is variable and controllable with the assistance of the switchable structure of nanoporous materials. The major focus of this Review is on possible reaction pathways/mechanisms and the relationships between catalyst structure and catalytic performance. Moreover, representative examples of catalytic upgrading of biobased platform molecules to biochemicals and fuels through selective C-C cleavage and coupling strategies over nanoporous acidic materials are also discussed.

A one-pot method for the enhanced production of xylitol directly from hemicellulose (corncob xylan)

An efficient one-pot reaction system for converting hemicellulose (corncob xylan) into xylitol was developed by using a heterogeneous catalyst and water as solvent, without the presence of any acids.