Structure of Simpler Organic Compounds. 99 



sented by the above formulae, form a very important class 

 of compounds. Where R x R" and R w represent complex 

 radicles that is, when glycerol has undergone condensa- 

 tion with acids of high molecular weights, such as palmitic, 

 stearic acids, etc. the substances known as the fats and 

 fatty oils are produced. The chemistry of these sub- 

 stances will be discussed in detail later. 



To summarize, the esters are substances produced by 

 the condensation of alcohol with acids, of which the most 

 important class, as far as the subject of this book is con- 

 cerned, are those formed by condensation of the alcohols 

 with the organic (carboxylic) acids. In this case the 

 effect of mixing alcohols and acids may be represented by 

 the general equation 



ROH + R'-COOH 7 * H 2 + RO-CO-R' 



The process, known as esterification, is a reversible one, 

 and only proceeds to completion (or towards completion) 

 in the presence of a reagent which withdraws water from 

 the sphere of action. The esters are neutral substances, 

 which are readily hydrolyzed by alkalis in accordance 

 with the equation 



R-0 CO R' + NaOH = R'.CO-ONa + R OH 



This process is generally known as " saponification." 

 In the case of alcohols containing more than one hydroxyl 

 group, one or more of such groups can take part in ester 

 formation. In the case of glycerol, when ester formation 

 has taken place between the three hydroxyl groups and 

 higher fatty acids, the fats and fatty oils are obtained, 

 which on hydrolysis with caustic alkalis give rise to 

 glycerol and alkali salts of the fatty acids, which are 

 generally known as the soaps. 



