CHEMISTRY 203 



R, a few of the most simple and important 

 divisions are as follows : — 



Alcohols, primary RCH 2 OH 



Alcohols, secondary R 2 CHOH 



Alcohols, tertiary R 3 COH 



Aldehydes R CHO 



Ketones R 2 CO 



Acids RCOOH 



Esters RCOOR 



Ethers ROR 



By the introduction of oxygen into the 

 molecule any complex hydrocarbon may be 

 converted into a great number of substances, 

 and even in simple cases such derivatives 

 are not few. In the accompanying formulas 

 I have gathered together the possible hydro- 

 carbons containing three carbon atoms (ex- 

 cluding ring compounds), and their possible 

 oxygen derivatives, most of which are capa- 

 ble of existence as substances of varying 

 stability, many of them being in fact well- 

 known common substances like lactic acid, 

 glycerine, propionic acid, propyl alcohol, two 

 of the simplest sugars, etc. 



