Fractionation of Wood Polymers by Carboxymethylation-Influence of Reaction Conditions

This study has shown that the reaction conditions had a significant influence on the carboxymethylation (CM) of wood in terms of the formation of water-soluble materials, which was significantly higher from a hardwood (aspen) as compared to a softwood (spruce) sample under similar conditions. The water-soluble material was derived mainly from the hemicelluloses and cellulose components and contained less than 10% of residual lignin. Among the solvents examined, 2-propanol and an acetone/ethanol (7:3) mixture were more effective than others. The CM of wood polymers was considerably affected by the chemical charges of alkalis and monochloroacetic acid. Also, a hot water pre-extraction of wood samples significantly enhanced the reactivity of the cellulose component and would facilitate the preparation of the carboxymethy-cellulose (CMC).