The reductive catalytic fractionation of flax shives in the presence of bimetallic NiRu catalysts supported on oxidized carbon materials (CM) such as mesoporous Sibunit and carbon mesostructured by KAIST (CMK-3) was studied. The catalysts based on CMK-3 were characterized by a higher surface area (1216 m/g) compared to the ones based on Sibunit (315 m/g). The catalyst supported on CMK-3 (10Ni3RuC400) was characterized by a more uniform distribution of Ni particles, in contrast to the Sibunit-based catalyst (10Ni3RuS450), on the surface of which large agglomerated particles (300-400 nm) were presented.
View Article and Find Full Text PDFTo ensure the high quality of water, it is necessary to remove toxic pollutants. At present, purification of water is implemented using various sorbents. The efficient sorption materials are modified polysaccharides.
View Article and Find Full Text PDFCellulose sulfates are important biologically active substances with a wide range of useful properties. The development of new methods for the production of cellulose sulfates is an urgent task. In this work, we investigated ion-exchange resins as catalysts for the sulfation of cellulose with sulfamic acid.
View Article and Find Full Text PDFWater-soluble azo derivatives of lignin were synthesized by the azo coupling reaction using organosolv ethanol lignin and diazonium salts based on sulfanilic acid and p-nitroaniline. The structure of azo derivatives of lignin were studied by nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and gel permeation chromatography. It was found that the azobenzene bonds formed in the azo coupling reaction of macromolecules impart the photosensitive properties to the synthesized polymers via cis-trans photoisomerization of the diazobenzene group.
View Article and Find Full Text PDFArabinogalactan 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.
View Article and Find Full Text PDFIn this study, hemicelluloses of aspen wood () were obtained by oxidative delignification in an acetic acid-water-hydrogen peroxide medium at temperatures of 70-100 °C and a process time of 1-4 h. The maximum polysaccharide yield of up to 9.68 wt% was reported.
View Article and Find Full Text PDFDouble activation catalysis was experimentally observed in hydrolysis of cellobiose catalyzed simultaneously with phthalic and hydrochloric acids, confirming earlier theoretical prediction known from literature. Both acids can catalyze the reaction individually, and contribution of the double-activation pathway to the total reaction rate declines as temperature increases. In fact, above a certain temperature, the hydrolysis rate in presence of both acids becomes lower than the sum of the rates for the two acids acting individually.
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