Methods for the Selective Oxidation of Cellulose: Preparation of 2,3-Dicarboxycellulose and 6-Carboxycellulose
article
Three methods for the selective oxidation of cellulose are described. The classical method consists of consecutive oxidation with sodium periodate, leading to 2,3-dialdehyde cellulose and sodium chlorite, giving 2,3-dicarboxy cellulose. This material, which is obtained in high yield and has a high carboxylate content (7.6 mmol COONa/g; 90% of the theoretical value), has a very good calcium sequestering capacity. The second method is by oxidation of the substrate, dissolved in concentrated phosphoric acid with nitrite/nitrate, leading to the selective oxidation of the substrate at the 6-position of the glucose unit. Generally, the yields are higher than 80%, and the degree of oxidation is 80-90%. However, the reaction is not completely specific, since some oxidation at the secondary hydroxylic groups occurs. Borohydride reduction of the product restores the diol configuration and also ß-elimination is avoided and thereby depolymerization. Oxidation with sodium hypochlorite and bromide as a catalyst and TEMPO as a mediator appears also to be applicable to cellulose. Selectivity of oxidation at the 6-CH2OH group is somewhat lower than that obtained earlier for glucans like starch and pullulan. Products with a degree of oxidation of 80% are obtained in 90% yield or higher.
TNO Identifier
234810
ISSN
00976156
Source
ACS Symposium Series, 688, pp. 73-82.
Pages
73-82
Files
To receive the publication files, please send an e-mail request to TNO Repository.