QUANTITATIVE DETERMINATION OF MIXTURES OF ALKYL ETHERS OF D-GLUCOSE .2. STRUCTURAL STUDIES OF PARTIALLY METHYLATED COTTON CELLULOSE

The distribution of methoxyl groups in repeatedly methylated cotton cellulose is in agreement with the suggestion that the elementary fibril is the basic structural element and suggests that a simple model for these elementary fibrils would have an average cross-section of 8 × 10 cellulose chains. The dimensions of such a cross-section are approximately 40 × 50 Å and agree closely with electron-microscopical observations. This fibril has a surface in which all of the readily accessible hydroxyl groups lie. Methylation of these hydroxyl groups is quite rapid, but the methylation of hydroxyl groups below this surface takes place at a lower rate. The slower reaction proceeds with little change in methoxyl group distribution, other than the appearance of tri-substituted d-glucose units at a rate similar to that of the disappearance of d-glucose; it is suggested that this stage of the reaction occurs with an advancing zone of methylation passing through ordered material. Evidence has also been obtained for aggregation of the elementary fibrils. © 1969.