ACTION OF CHEMICALS ON CELLULOSE 153 



anhydride in the presence of concentrated sulphuric acid or zinc 

 chloride converts cellulose into acetyl cellulose, which is insoluble 

 in water but soluble in several organic solvents. Acetyl cellu- 

 lose is also used in the manufacture of artificial silk. 



Cellobiose,* C l2 H Zyi O llt 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 ; since cellulose 

 and starch yield different disaccharides on hydrolysis, it would 

 appear that these two substances are fundamentally different 

 and that cellulose is not a higher polymer of starch. 



Cellobiose reduces Fehling's solution and gives an osazone, 

 m.p. 208-210. 



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. 

 I -25) at 1 80 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, and hydrochloric acid, etc. 

 The nature of these oxycelluloses differs somewhat according 

 to their mode of formation, but in general they are charac- 

 terized by the fact that they yield a relatively large amount ot 

 furfurol on boiling with hydrochloric acid ; they are hydro- 

 lized by boiling with milk of lime into isosaccharic and dioxy- 

 butyric acids ; they also reduce Fehling's solution, and are dyed 

 by basic dyes, such as methylene blue. f 



The fact that the cellulose obtained from esparto grass 

 and cereal straws resembles oxycellulose, in yielding a con- 

 siderable proportion of furfurol on boiling with hydrochloric 

 acid, leads to the idea that cellulose from these sources con- 

 tains oxycellulose, but whether or not such oxycelluloses are 

 actually pre-existent in the plant fibre has not yet been defi- 

 nitely established (see Lignocellulos.es). 



Oxygen containing 2 per cent of ozone at once attacks 

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



*Skraup and Konig: " Ber. deut. chem. Gesells.," 1901, 34, 1115; Schlie- 

 mann : " Annalen," 1911, 378, 366. 



fDoree: "J. Chem. Soc.," 1913, 103, 1347- 



