The conformation of the anhydrocellobiose units in cellulose I and II

Abstract

SynopsisIt is postulated from energetic considerations that the anhydrocellobiose unit in cellulose I has a conformation differing from that in cellulose 11. Conformation I has two intramolecular hydrogen bonds, while conformation I1 has only one. This difference a r k s from a different orientation of the C(6)-hydroxyl group in the two conformations. Their interconversion is shown to be dependent upon the polarity of the medium. The assignment of conformation I to cellulose I and conformation I1 to cellulose I1 and the equilibrium between them appear to be consistent with a number of experimental observations reported in the literature.