Some hemicellulose extraction methods

Abstract

Pretreatment of willow sawdust with ethanolic solutions of alkali either (a) alone or (b) in alternation with chlorination allows extraction of hemicelluloses by boiling water or 1% Na2SO3 soln. Extraction after the 2 types of pretreatment follows different courses, (b) removing material of higher furfuraldehyde yield than (a). Completeness of extraction of hemicelluloses varies with the intensity of pretreatment, and does not run parallel with the degree of delignification. A clear differentiation of encrusting and cellulosan hemicelluloses is not possible by these methods of extraction, each class showing graded ease with which it is rendered water-soluble; there is considerable overlap around the end-point of chlorina-tion-cellulose prepn.