PROPERTIES OF CELLULOSE HYDROXAMIC ACID DERIVATIVE AND ITS METAL-CHELATING COMPLEXES

Abstract

Hydroxamic acid derivatives were prepared from dialdehyde celluloses obtained by periodate oxidation of cellulose according to an improved method for the preparation described by Gal'braikh and Rogovin (Vysokomol, Soedin., 5, 693 (1963)). Mild oxidation of the dialdehyde celluloses with acidified sodium chlorite led to 2, 3-dicarboxy celluloses, which gave the dimethyl esters by treatment at room temperature under the presence of large amounts of methanol containing 0.06-0.1N hydrogen chloride without causing degradation by methanolysis. The esters were converted into the corresponding hydroxamic acid derivatives by the action of an absolute methanol solution of hydroxylamine adjusted at pH 9.2-3 by newly prepared sodium ethylate. The hydroxamic acid derivatives were found to be isolated in a yield of more than 80% as sticky massive solid from the reaction mixture by shaking with a mixture of EtOH:H₂O (80:20 v/v). The formation of the hydroxamic acid derivatives was confirmed by analyses of the nitrogen content and the characteristic coloration with ferric chloride solution. Some properties of the metal chelating complexes of hydroxamic acid derivatives prepared were investigated. The hydroxamic acid derivatives formed chelating complexes of colored precipitates with copper or ferric ion, but the chelating complexes formed by such ions as cobalt, nickel and zinc gave no precipitate. After uptake of metallic ions by the hydroxamic acid derivatives from the mixture, the contents of metallic ions remaining in the supernatant separated by centrifugation were determined by the chelatometric titration method. By this determination, it was proved that the hydroxamic acid derivatives had a high ability to take up such specific ions as ferric or copper ion preferencially from their mixture with other kinds of metallic ions. This findings suggests that the hydroxamic acid derivatives from cellulose may be useful as a material for recovery of the specific ions.