Celluronic acids

It is possible to oxidize all the CH2OH groups to carboxylic groups, if the conditions of reaction are sufficiently severe, when the content of COOH may reach 25%. The product obtained in this way is a polyanhydroglucuronic add, known as carboxycellulose or celluronic acid. When half the CH2OH groups present in the cellulose are oxidized, a product with a 13% COOH content is obtained, soluble in dilute solutions of caustic soda, ammonia and sodium carbonate. Celluronic acid can form esters with nitric acid. The properties of these esters will be discussed later. 

Celluronic acid nitrates (carboxycelluloses nitrates). Celluronic acid obtained by treating cellulose with nitrogen dioxide may then be esterified by means of nitric acid. 

To characterize the properties of the product obtained by esterifying celluronic acid with nitric acid, Rogovin, Treyvas and Shorygina [64] have reported the following numerical data, collected in Table 86. 

In order to explain the low solubility of celluronic acid nitrates Rogovin et al. 

To explain the appreciable solubility of the product, Rogovin et al. suggest that the carboxylic groups of alginic acid are probably internally esterified with hydroxyl groups. Thus (as with pectic acid nitrates, see above) no cross-links can be formed of the type assumed by the same authors to exist in celluronic acids and in celluronic acid nitrates (see below). 

Celluronic acid produced by treating cellulose with nitrogen tetroxide may then be esterified by means of nitric acid. It has been found that even in. the presence of small number of carboxylic groups a considerable change in the properties of the nitric esters is brought about, as compared with cellulose. 

The result of nitrating celluronic acid (after Rogovin, Treyvas, Shorygina [4])... 

Kenyon and coworkers found that celluronic acids are degraded in alkaline solution to generate acidity, and suggested that this alkali-lability is due to the presence of small proportions of ketonic groups in these products. They postulated that the ketone groups enolize in alkali, the enediols then split, and adjacent glycosidic links hydrolyze in such a way as to initiate an extensive alkaline degradation. 

Nitration with mixtures of nitric and phosphoric acids Nitration with mixtures of nitric and acetic acid (or acetic anhydride) Nitration in mixtures and solutions including inactive substances Nitration with nitric acid in the presence of inorganic salts Nitration with nitrogen oxides Celluronic acid nitrates (carboxycelluloses nitrates)... 

Celluronic acid (carboxyccllulosc) nitrates DiaUehydc cellulose niiraic Copolymers of nitrcxellulosc Niifosiarch... 

Cellulosic acid, SCI. Celluronic acid. Oxidized cellulose. Monocarboxycellulose. Polyanhydroglucuronic acid [9032-53-5]... 

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