I40 THE CARBOHYDRATES 



alkali cellulose with carbon disulphide, when a change, which 

 may be represented by the following equation, takes place : — 



/OR 

 RONa + CSa = CSC^ 



Various alternative structural formulae have been suggested. 

 CH COH CO CHOH— CH— CHOH 



CHOH CHOH CHOH CHOH CHOH CHOH 



c!hOH tnOH CHOH tnOH °' CHOH CHOH CHOH-CH-CH, 



COH ■""" CH CHj 



Cross and Bevan's formulae.* Green's formula. f 



O CH— CHOH 



I I 



O CHOH 



iH. J 



CHa— CH— CHOH 

 Vignon's formula.^ 



Green § is of opinion that although cellulose is a colloid 

 it does not follow that it has a high molecular weight. He 

 considers that his formula well explains the following facts 

 among others : — 



1. That the highest nitrate obtainable from a cellulose 

 molecule containing six carbon atoms is a trinitrate.il 



2. That the highest acetate obtainable from a cellulose 

 molecule containing six carbon atoms is a tri-acetate. 



3. That cellulose does not react with phenylhydrazine, but 

 on hydrolysis readily yields carbonyl groups which are able 

 to react. The formula and its arguments are, however, not 

 accepted by Cross and Bevan.lF 



Dreaper regards cellulose as a typical colloid, and, as a 



* Cross and Bevan : " J. Cham. Soc," 1901, 79, 366. 



t Green and Perkin : " J. Chem. Soc," 1906, 81, 811. 



X Vignon : " Bull. Soc. Chim.," 1899, 21, 599. 



§ Green : " Zeit. f. Farb. u. Textil Chemie," 1904, 3, 97, 309. 



II It should be clearly understood that by the nitration of cellulose it is pos- 

 sible to obtain a whole series of esters, representing different degrees of nitration. 

 These various compounds may be described as mono-, di-, tri-, etc., up to 

 deka , or possibly dodeka-nitrates of a cellulose molecule containing twenty-four 

 carbon atoms. What is commonly called cellulose hexanitrate, the substance 

 employed in the manufacture of gun-cotton is calculated on a Cjj molecule, 

 which, therefore, corresponds to a trinitrate of a Cg molecule. 



1[ Cross and Bevan : "Zeit. f. Farb. u. Textil Chemie," 1904, 3, 197. 



