Abstract
THE British Cotton Industry Research Association has recently issued two memoirs (reprinted in the Journal of the Textile, Institute, vol. 20, T. 373, 1929; and vol. 21, T. 225, 1930) in which S. M. Neale describes some work on the physical chemistry of cellulose. Regarding cellulose as a linked series of glucose residues with −OH and −O-groups as reacting points, it is shown that the behaviour in alkaline solutions can be explained by treating the −OH groups as sources of potential acidity, with their capacity for liberating hydrion governed by the law of mass action, so that an average dissociation constant can be assumed for the primary acid ionisation of cellulose in any state of complexity. In developing this idea it is necessary to employ the Donnan equation of membrane equilibrium to allow for the fact that the assumed cellulose ion is coherent and unable to diffuse. By assuming an approximate value of 2 × 10−14 for the dissociation constant it is possible to calculate approximately the osmotic swelling pressure of cellulose in solutions of caustic soda of any concentration. The calculated osmotic pressure curve is strikingly similar to the curve obtained by plotting the imbibition of water by regenerated cellulose (cellophane sheet) against the concentration of alkali in which it is placed, while the amounts of alkali taken up are shown to be consistent with the stoichiometric conversion of cellulose into the mono-sodium salt at high alkali concentrations, when allowance is made for the alkali imbibed in accordance with the Donnan equation.
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Cellulose and Sodium Hydroxide. Nature 126, 151 (1930). https://doi.org/10.1038/126151a0
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DOI: https://doi.org/10.1038/126151a0