Hemicellulose preparation and chlorination cellulose

Abstract

The results presented are based on an examination of mahogany and willow sawdusts. Treatment of woods with boiling alcoholic-NaOH results in considerable destruction of furfuraldehyde-yielding material. The extent of the destruction varies with the type of wood. Extraction of hemicelluloses by this reagent decreases with increasing alcohol conc. and substantially stops when this reaches 70%. Such hot extraction favors the removal of non-pentosan, apparently from the cellulosan fraction, whereas extraction with 4% NaOH in the cold favors the dissolution of para-xylan. Thus, hemicellulose preparations obtained by the usual methods are mixtures, derived partly from the incomplete extraction of encrusting hemicelluloses of the cell-wall and partly from the cellulosan, including glucosan and para-xylan. The proportions of these constituents present in a hemicellulose from any source will depend on the nature of the plant material treated, the method of extraction, and the susceptibility of the individual components to destruction under the conditions of extraction used.