A study of anhydrocelluloses – Is a cellulose structure with residues in a 1C4-conformation more prone to hydrolysis?

Abstract

A study of the effect of introduction of 3,6-anhydroglucose residues in the cellulose structure on glycoside hydrolysis rate was performed. A cellotetrose with an 3,6-anhydroglucose as the third residue was synthesised. Acidic hydrolysis of this tetrasaccharide showed that hydrolysis of the 3,6-anhydro-β-D-glucoside linkage was 31.400 times faster than hydrolysis of cellobiose. A series of different 3,6-anhydrocelluloses with different degree of substitution were prepared by tosylation of cellulose with varying amounts of tosyl chloride in dimethylacetamide and subsequent treatment with sodium hydroxide. Anhydrocelluloses with degrees of substitution of 0.02, 0.07, 0.31 and 0.74 were obtained. The anhydrocelluloses were subjected to acidic hydrolysis in 2.0 M aqueous HCl and the rate of hydrolysis monitored by ion chromatography analysis of the amount of glucose and/or cellobiose formed. All 3,6-anhydrocelluloses hydrolyzed with a faster rate than cellulose, but the anhydrocellulose with a low degree of substitution (ds = 0.07) hydrolyzed fastest which was 90 times faster than cellulose.