LIGNIN-CARBOHYDRATE BONDS IN A RESIDUAL SODA SPRUCE PULP LIGNIN

The behaviour of lignin-polysaccharide complex of spruce wood in soda pulping was studied by the characterization of lignin-saccharide fract ions isolated from a series of soda pulps. The dioxane pulp lignins co ntain 8-14% of carbohydrates in which glucose was the predominant comp onent. Its content increased with increasing degree of delignification indicating the formation of secondary lignin-carbohydrate linkage. Bo th glycosidic and ether type of bond between residual lignin and cellu lose in pulp was proved by methylation analysis of the pulp dioxane li gnin.