ISOLATION AND CHARACTERIZATION OF A CELLULOSE FROM THE INNER BARK OF WHITE BIRCH ( BETULA PAPYRIFERA )

Abstract

A pectic acid, a 4-O-methylglucuronoxylan, and a cellulose have been isolated from the inner bark of white birch (Betulapapyrifera), in addition to minor amounts of other polysaccharides. The cellulose, which comprised 28% of the bark, yielded only D-glucose on hydrolysis, had a number-average degree of polymerization of 315 and, on methylation and hydrolysis, gave 2,3,6-tri-O-methyl-D-glucose and 2,3,4,6-tetra-O-methyl-D-glucose in a mole ratio of 59:1. The O-methylcellulose had a degree of polymerization of 125, thus suggesting the possibility of branching. Direct nitration of the bark gave a nitrate in a yield corresponding to 28% cellulose in the bark. Light-scattering measurements on this derivative indicated a weight-average degree of polymerization of 7500. While the low intrinsic viscosity of this nitrate did not exclude the possibility of branching, further evidence is needed to establish the linear or non-linear nature of birch bark cellulose.