DERIVATIVES OF ALCOHOLS AND ACIDS 57 



as they are present in exceedingly small amounts. Esters that 

 have been prepared synthetically from some of the middle 

 members of the acid and alcohol series do, however, possess the 

 odors of certain fruits, and on that account are prepared and 

 used as artificial fruit flavors or fruit essences. Some of these 

 are as follows : 



Ethyl butyrate. Pineapple essence ; 



Iso-amyl-iso valerate, Apple essence ; 

 Amyl butyrate, Apricot essence ; 



Iso-amyl-acetate, Pear essence ; 

 etc. 



Fats, Oils and Waxes 



These important plant and animal substances are all true 

 esters of alcohols and organic acids. 



Waxes. — The waxes are esters of monohydroxy alcohols, 

 similar to ethyl alcohol but containing a larger number of car- 

 bon atoms. Beeswax, for example, is composed mostly of the 

 ester of myricyl alcohol, CsoHeiOH, and palmitic acid, 

 C15H31COOH, i.e. myricyl palmitate, C15H31COOC30H61. 

 Spermaceti, a wax obtained from the head of the sperm whale, 

 is mostly the ester of cetyl alcohol, C16H33OH, and palmitic acid, 

 i.e. cetyl palmitate, C15H31COOC16H33. 



Fats and Oils. — The fats and oils of vegetable or animal 

 origin are true fats and oils as distinguished from numerous 

 compounds commonly termed oils, e.g. petroleum oil, oil of 

 turpentine, oil of hitter almonds, etc. They are composed of 

 mixtures of esters of the trihydroxy alcohol, glycerol and numer- 

 ous acids, mostly the monobasic acids of the parafl&n series of 

 hydrocarbons, which have been given previously. The acids 

 which are most common as constituents of fats and oils are, 

 butyric, capric, lauric, myristic, palmitic, stearic and arachidic. 

 This explains the designation of this series of acids as the fatty 

 acids. The names given to these acids indicate their natural 

 source in plants or animals : 



