22 Cellulose 



saponified and removed in solution in the alkaline lye. The 

 oxidation processes which follow viz. treatment with the 

 hypochlorites, permanganates, &c. in dilute solution although 

 they may be regarded as the bleaching processes proper, really 

 accomplish very little beyond removing residues or by-products 

 of the alkaline treatment. It is also evident that resistance to 

 alkaline treatment is a very important condition in the every- 

 day uses of cellulose textiles. 



H. Tauss has recently investigated the action of alkaline 

 solutions upon various celluloses at high temperatures (J. Soc. 

 Chem. Ind. 1889, 913; 1890, 883). Purified cotton cellulose, 

 digested with solutions of sodium hydrate of 3 p.ct. Na 2 O three 

 times in succession, is attacked and converted into soluble 

 products in the following proportions, increasing with the temper- 

 ature at which digested : 



I atm. pressure .... I2'l p.ct. 

 5 .... 15-4 



10 .... 20-3 



Strong aqueous solution of ammonia is without sensible action 

 on cellulose until a very high temperature is reached. At 200 

 combination ensues, and the entrance of the NH. 2 residue into the 

 cellulose molecule is evidenced by the increased attraction of the 

 product for colouring matters, approximating to that of the animal 

 fibres. (L. Vignon.) 



We have mentioned that digestion with 3 p.ct. solutions of soda 

 (Na. 2 O) at high temperatures produces a certain conversion of 

 cellulose into soluble substances. Solutions of 8 p.ct. (Na 2 O) 

 strength have been found to give the following results (Tauss, 

 loc. tit.} : 



I atm. pressure . . . 22-0 p.ct. dissolved 

 5 ... 58-0 



10 ... 59'0 



In connection with these observations it is to be noted that a 

 process of estimating the cellulose in compound celluloses (wood) 

 has recently been proposed (Lange, Zeitschr. f. Physiol. Chem. 14), 

 jmd adopted by other observers, based upon the action of strong' 



