Physicochemical characteristics of polysaccharides from catalytic and noncatalytic acetic acid-peroxide delignification of larch wood

The composition and physicochemical characteristics of polysaccharides extracted from spent liquors of catalytic and noncatalytic delignification of larch wood in the acetic acid-hydrogen peroxide medium were studied. The following were used as catalysts: (NH4)6Mo7O24, MnSO4, TiO2, and ZnSO4. The structure of polysaccharides was identified by FTIR and NMR spectroscopy. Their composition was established using gas chromatography, and the physicochemical characteristics were studied using gel permeation chromatography, scanning electron microscopy, thermogravimetric analysis, gas adsorption, and elemental analysis. It was shown that in the process of oxidative delignification, a significant amount of hemicelluloses and arabinogalactan passes into the spent liquor. The yield of polysaccharides was up to 16.9 wt%. Polysaccharides had a weight-average molecular weight of up to 22.9 kDa and a narrow molecular weight distribution.