The hydrolysis of cellulose part II. Acid sensitive linkages in egyptian cotton

It has been shown that a hydrolytic study of the kinetics of chain degradation can be used to detect the presence of acid‐labile linkages in cellulose, provided that the amount of ordered or crystalline material in the sample is first reduced by a treatment involving regeneration from alkaline solutions. The results for Egyptian cotton regenerated from benzyl trimethyl ammonium hydroxide in the absence of oxygen show that only a very small fraction of acid‐labile linkages—less than one per 2900 glucose residues—can be present in the original chain molecules. It is possible that even this small amount is produced during the alkali treatment. Thus weak bonds of the types proposed by Schulz and Pacsu are definitely absent. Cotton regenerated from cuprammonium and cupriethylenediamine solutions, however, does contain randomly distributed linkages which are approximately 10,000 times more sensitive to acids than the normal glycosidic type. These appear to be formed from a limited number of special sites in the chain molecules, by oxidation in alkaline solution. Assuming the value of P̄n for undegraded cotton to be 2900, the amount of these extranormal linkages is one per 660 glucose residues.