CELLULOSE 21 r 



diluted, a gelatinous hydrate is precipitated ; this substance 

 is known as amyloid, since it resembles starch in giving a blue 

 colour with iodine. The same substance is formed by the 

 action of chlorzinc iodide, the reaction being used as a test 

 for cellulose. 



Cellulose on hydrolysis yields glucose only. Several claims 

 to have effected the quantitative conversion of cellulose into 

 glucose were made on the basis of observations of the change in 

 optical activity, but the first to obtain an approximately 

 quantitative yield of crystalline glucose from cellulose was 

 Monier Williams * who left the cellulose in contact with 72 

 per cent sulphuric acid for a week and then after dilution 

 boiled the mixture for fifteen hours. 



The combined action of glacial acetic acid and acetic anhy- 

 dride in the presence of concentrated sulphuric acid or zinc 

 chloride converts cellulose into acetyl cellulose, which is insol- 

 uble in water but soluble in several organic solvents. Acetyl 

 cellulose is also used in the manufacture of artificial silk. 



Cellobiose,f C12H22O11, is a disaccharide obtained in the 

 form of its acetate by acting on cellulose with acetic anhy- 

 dride and concentrated sulphuric acid. It stands in the same 

 relation to cellulose as does maltose to starch. 



3. Oxidizing Agents. — Dilute solutions of alkaline hypo- 

 chlorites have very little action on typical cellulose, and can 

 therefore be employed for bleaching this material ; with con- 

 centrated solutions of hypochlorites, however, a general decom- 

 position ensues. As already mentioned, nitric acid (sp. gr. 

 1-25) at 180° converts cellulose into a series of oxidation 

 products known as oxycellulose, and similar substances are 

 produced by the action of other oxidizing agents, such as 

 chromic acid, potassium chlorate in the presence of hydro- 

 chloric acid, etc. 



Oxygen containing 2 per cent of ozone at once attacks 

 dry cotton with the formation of a cellulose peroxide % and an 

 acid substance ; the latter, when boiled with water, dissolves, 



* Monier Williams : " J. Chem. Soc," 1921, II9» 803. 

 I Skraup and Konig : " Ber. deut. chem. Gesells.," 1901. 34, 1115 ; 

 Schliemann : " Annalen," 191 1, 378, 366. 



JDoree: " J. Chem. Soc," 1913, 103, 1347. 



14* 



