Oxycellulose acidic

Another important characteristic of oxycellu-lose is the presence of —COOH groups, which may be detd by measuring the amt of C02 evolved when oxycellulose is distilled with 12% hydrochloric acid. While, according to Marsh Wood (Ref 6) and Dorep (Ref 7), the amt of —COOH contained in oxycellulose is between 0.3 and 1.3%,... 

C3 H, 04 mw 104.06. One of the products of the alkaline saponification of NC and nitro-oxycellulose (Ref 1). Berl and Smith (Ref 3) obtained it, calling it oxypyruvic acid, by the alkaline hydrolysis, not only of NC, but also of nitrates of glucose and levulose... 

As shown experimentally by Piest [75], cotton which was subjected to various operations, e.g. bleaching, treatment with alkalis or acids, strong heating prior to nitration furnishes nitrocellulose solutions of low viscosity. At the same time an increase in the solubility of the nitrocotton was also observed. This is evidence that the cellulose molecules are shortened and their content of terminal group is increased. A certain proportion of hydrocellulose and oxycellulose may result. The total effect is to bring about an increase in the reductive properties of the cellulose, i.e. an increase of the copper number. 

In concentrated nitric acid, sp. gr. 1.52, it dissolves on warming (80 to 90°C). As the result of the prolonged action of more dilute nitric add, specific gravity 1.41, a partial denitration and formation of oxycellulose occurs. 

In this book, he emphasized the importance of the microscopic and the submicroscopic structure of fibrous high polymers. The reactions of cellulose with water, aqueous alkalis, organic bases, ammonia, and strong salt solutions were all stressed. Special attention was given to various types of cellulose esters, to cellulose xanthate, and to the cellulose ethers. The oxidation of cellulose under a variety of conditions was described, as were the hydrolysis reactions. The latter included discussions on reversion and on the kinetics of acid hydrolysis. It is interesting to note that Heuser, who earlier had criticized the terms hydrocellulose and oxycellulose, and had... 

The methyl ester of oxycellulose, produced by alkaline permanganate oxidation of cuprammonium cellulose followed by treatment with diazomethane, has been reacted with protein by the azide method [34]. Acidic oxyce]]uloses are aiso able to react with alcohols and amines, including proteins, to form esters or amide derivatives. 

When cellulose is exposed to the unlimited supply of oxygen present as 21% of the air, unstable peroxide radicals form. In the autocatalytic reaction of cellulose oxidation, decomposition of peroxide forms cellulose radicals that react with oxygen to form R02- radicals. These radicals attack other cellulose molecules to form oxycelluloses (carbonyl, aldehyde, and carboxyl acid groups) along with more cellulose free radicals (34). 

Linen cellulose hydrolyzes at the acetal link. In acidic or neutral conditions, reducing oxycellulose is formed in alkaline conditions, a nonreducing oxycellulose is formed. The new end groups produced, then, are aldehydic in the first case and carboxylic in the second case. Hydrolysis and oxidation are nonuniform amorphous areas are attacked first (10). 

That carboxylic acid groups on the cellulosic chain play a minor role in the decay of the material is not surprising. As Davidson and Standing (10) and Davidson and Nevell (11) showed, acidic oxycelluloses are unstable because the carboxylic acids are converted to water-soluble, low molecular weight species. Thus, in old cellulosic textiles, the acidic species are removed from the fabric upon washing, and deacidification is not necessary. Kerr et al. (12) and more recently Hackney and Hedley (13) have provided independent evidence of the correctness of this view. Paper that has been subjected to sulfite pulping or that contains alum or rosin, which may form acids, responds well to deacidification because the additives are being neutralized. 

Norris and Resch determined furfural yields from uronic acids, under the conditions normally used for pentosan determination, and obtained about 37 to 44% of the theoretical yield of furfural. In later work, the effect of various furfural-yielding substances on one another was ascertained, and a standardized procedure was developed for analysis of the types of mixtures commonly met with in cell-wall chemistry. Apparently, the yield of furfural from uronic acids and polyuronides varies with the proportion of these substances present, and with their ratio to other sugars. From oxycellulose, TJnruh and Kenyon obtained furfural yields of 18 to 20 % of the theoretical on the basis of carboxyl content. Wise and Ratliff, however, in summative analysis of wood, used a correction based on the assumption that the uronic acids present evolve 35% of the theoretical amount of furfural. 

The reaction of oxycelluloses with hydroxylamine hydrochloride and determination of the freed acid, or of the nitrogen content of the product, has been used as a measure of the aldehyde content. Other methods for this determination are reduction with sodium borohydride or oxidation with chlorous acid. Strole has compared the hydroxylamine and borohy-dride methods and has shown that they give similar results. Oxidation with alkaline hypoiodite is not reliable for aldehyde-content determinations be-... 

Davidson prepared nitrate esters from oxycellulose and noticed that, above about 2 % D.O., the products were insoluble in acetone this observation has been confirmed. The explanation put forward to account for the diminished solubility was that formation of hemiacetal cross-links occurred in the presence of anhydrous, strong acids. An alternative explanation is that the cross-links were already present in the oxycellulose and that... 

Several theories have been proposed for the alkaline degradation of oxycelluloses of these theories, two have predominated. Pacsu considered oxycellulose to be a hydroxyketene acetal (120) degradation of such a compound would give glycolic acid and n-erythrose as the primary products. 

However, Head showed that glyoxal is produced by the treatment of both oxycellulose and periodate-oxidized methyl fl-cellobioside (121) with alkali. The other theory was that of Haskins and Hogshead, based on the p-alkoxycarbonyl elimination mechanism of Isbell for the formation of saccharinic acids on treatment of sugars with alkali. They suggested that fission of the C5—O bond would yield glyoxal and n-erythrose. Recent work has indicated that the degradation is, indeed, based on a jS-alkoxycarbonyl elimination, but the products are different from those postulated above. 

An interesting observation was made by Davidson and Nevell when studying the cuprammonium fluidity of oxycelluloses partially oxidized with chlorous acid, namely, that the more-easily oxidized aldehyde group contributed more to the alkali lability. This is, in fact, further evidence for the existence of the hemiacetal with a six-membered ring (113) this has a i9-alkoxycarbonyl group and, from the work of Jayme and Maris, contains the more-easily oxidized aldehyde group. 

Much work has been performed on oxycelluloses in an effort to lessen their alkali-lability. Reduction, " oxidation with chlorous acid, "" 180,206 reaction with diazomethane """ have been found to be effective. 

The uses of periodate-oxidized carbohydrates are thus far confined to uses for oxycelluloses and, more particularly, oxystarches ( dialdehyde starches ). Following the development of the electrolytic regenerative process for periodic acid, oxystarch has been produced commercially in the United States by the Miles Chemical Company of Elkhart, Indiana. 

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