Structure of Simpler Organic Compounds. 83 



The general properties of the aldehydes may be sum- 

 marized as follows : 



They are obtained by the oxidation of primary alcohols 

 to which they stand in a definite genetic relationship. 

 Into these substances they can be reconverted by treatment 

 with nascent hydrogen. They are readily oxidized, and 

 therefore act as " reducing agents" yielding, with suitable 

 reagents, "fatty" acids containing the same number of 

 carbon atoms. On treatment with phosphorus penta- 

 chloride they yield dichloro derivatives, with two chlorine 

 atoms attached to the same carbon atom. They yield 

 characteristic addition products with sodium bisulphite, 

 ammonia, and hydrocyanic acid, and with alcohol a series 

 of products known as the acetals. Finally, they enter into 

 characteristic reactions with the substances phenylhy- 

 drazine, hydroxylamine, and semicarbazide to form pro- 

 ducts which serve to characterize them. Their constitution 

 is represented by the general formula R C = 0. 



V 



Part V. The Ketones. 



The ketones are produced from the secondary alcohols 

 by oxidation in a way similar to that in which the alde- 

 hydes are produced from primary alcohols. The formation 

 can be represented by the general equation 



R'v R v 



2 >CHOH+0 2 = 2 >CO + 2H 2 

 R/ R'/ 



where R or R' may be the same or different alkyl radicles. 

 As an example of this reaction, the production of the 

 simplest member of the class, namely, acetone, from iso- 

 propyl alcohol, may be quoted 



CH 3X CH 3X 



2 )CHOH + 2 = >CO + 2H 3 

 CH/ CH/ 



