OXIDATION PRODUCTS OF ALCOHOLS 45 



Phenyl Hydrazones. — An exactly analogous reaction takes 

 place with a benzene derivative known as phenyl hydrazine 

 which has the formula H2N — NH — CgHb. The reaction is : 



/H /H 



CH3-C = (O+HsjN-NH-CeHs^- CH3-C = N-NH-C6Hs+H20 



Aldehyde Phenyl hydrazine Phenyl hydrazone 



The product is known as a phenyl hydrazone. 



Both of these last reactions are due to the presence in alde- 

 hydes of the group — C = O called the carhonyl group. This 

 group is characteristic of aldehydes and ketones, the latter being 

 very similar to the aldehydes. In aldehydes the carbonyl car- 

 bon has one valence satisfied by a carbon radical, the other by 

 hydrogen. In ketones both are satisfied by radicals. 



H CH3 



CH3-C=0 CH3-C = 



Aldehydes Ketones 



(Acetaldehyde) (Acetone) 



This will be sufficient reference to ketones as we shall wish 

 simply to understand them as a class. 



The hydrogen cyanide, hydroxyl amine and phenyl hydrazine 

 reactions just discussed are of especial importance in connec- 

 tion with the study of the carbohydrates and will be referred 

 to again when we consider these compounds. 



EXPERIMENT STUDY X 

 Aldehydes 



(i) Formaldehyde, {a) Place 5.0 c.c. of methyl alcohol in a large 

 test tube. Heat a spiral coil of copper wire red-hot, and without 

 cooling drop it carefully into the tube of alcohol. When the flame 

 dies out notice the odor of formaldehyde in the tube. 



{b) Observe general properties of formalin, which is a 40 per cent 

 water solution of formaldehyde. 



(c) (Do this in a hood.) To about 5.0 g. of potassium perman- 

 ganate in a beaker add 5-10 c.c. formalin. Note odor of formalde- 



