CONSTITUTION OF CELLULOSE 159 



3. The fact that on destructive distillation it yields acetic 

 acid and methyl alcohol points to the presence in the molecule 

 of a CH 2 CO grouping. 



4. It is a very stable substance, which resists alkalis, 

 oxidizing agents, and, to some extent, acetylation, except in 

 the presence of a condensing agent, such as zinc choride or 

 sulphuric acid. 



5. With strong acids it yields esters, e.g. nitrates, acetates, 

 and benzoates. 



6. It undergoes the thio-carbonate reaction by treating 

 alkali cellulose with carbon disulphide, when a change, which 

 may be represented by the following equation, takes place : 



/OR 

 RONa + CS a = CS/ 



^SNa 

 Various alternative structural formulae have been suggested. 



CH --- COH CO CHOH CH CHOH 



^\ ^\ ^\ I I 



CHOH CHOH CHOH CHOH CHOH CHOH V V 



CHOH CH ~ CH 



CHOH CHOH CHOH CHOH ' C 



HOH CHOH 



CH CH 2 



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



O CH CHOH 



JO CHOH 

 H 2 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 : 



I. That the highest nitrate obtainable from a cellulose 

 molecule containing six carbon atoms is a trinitrate.il 



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



f Green and Perkin : id., 1906, 8l, 811. 



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



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



|| 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 



