28 THE CHEMISTRY OF CATTLE FEEDING 



e.g. acetic acid, have practically no effect upon it. On heating 

 in sealed tubes with acetic anhydride and sodium acetate, it 

 yields a tetracetate, (C 2 H 3 O 2 ) 4 C 6 H 6 O. This marks the limit 

 of acetylation, and it indicates the presence of four hydroxyls 

 in the C 6 H 10 O 5 group. The formula may therefore be written, 

 provisionally, as C 6 H 6 O(OH) 4 . 



Nitrates, hydrogen sulphates, and other esters can also 

 be prepared. Cellulose trinitrate, C 6 H 7 O 2 (N0 3 ) 3 , is a highly 

 explosive compound. It is often (wrongly) called " tri-nitro- 

 cellulose," or " gun cotton." The hydrogen sulphate, 

 C 6 H 8 O 3 (SO 4 H) 2 , is very unstable. It is produced only by 

 the action of concentrated acid which rapidly resolves the 

 compound into dextrine, and this into dextrose, which is then 

 dehydrated and charred. 



All the esters are easily saponified. On addition of water 

 a highly hydrated form of cellulose is precipitated as a colloidal 

 jelly containing an indefinite amount of water. (Cf. hydrates 

 of silica, alumina, etc.). 



More dilute nitric acid, sp. gr. 1*2, converts cotton into 

 a compound called oxycellulose, which, on analysis, is found 

 to correspond to the formula, C 18 H 26 O 16 . Comparing this 

 with 3(C 6 H 10 O 5 ) C 18 H 30 O 15 , it will be seen that oxy- 

 cellulose contains more .oxygen and less hydrogen in pro- 

 portion to carbon than the original compound. Oxycellulose 

 is a definite compound and forms a trinitrate, C 18 H 23 Oi 3 (NO 3 ) 3 . 

 It appears, therefore, that either the molecule of the original 

 cotton contains 18 atoms of carbon if not, the C 6 H 10 O 5 

 groups have been condensed or a more complex molecule 

 has been broken down. Other reagents, e.g. chlorine, chromic 

 acid, and permanganate of potash, also convert cotton into 

 oxycellulose. When oxycellulose is distilled with hydrochloric 

 acid, sp. gr. ro6, it yields furfural. 



X C.(CHO).CH 



\ I 



\CH CH 



Dilute alkalis have little or no effect upon cotton, but 

 more concentrated solutions combine with it, forming alkali 



