42 FATS, OILS, AND WAXES 



chemical constitution in so far as they are esters, but they 

 differ in the nature of their alcohol constituent which is not 

 glycerol but is usually a monohydric alcohol such as cetyl 

 alcohol Cic.HaaOH, carnaubyl alcohol C24H4gOH, pisangceryl 

 alcohol C24H49OH, ceryl alcohol CjisHj^gOH, myricyl alcohol 

 CggHjijOH, cholesterol or phytosterol. 



In addition to the acids already mentioned as occurring in 

 fats, the following are also met with in waxes in the form of 

 esters : ficocerylic acid CigHo.-.Oj, carnaubic acid Co4H4gO,^, and 

 pisangcerylic acid C24H4j^02, as well as acids belonging to 

 series of the general formula CnH2n_202 and CnH2n03. 



The term wax used in the chemical sense has reference 

 only to the chemical composition of these substances, regardless 

 of their physical state of aggregation, and consequently both 

 liquid and solid waxes are known. 



Waxes of the former class are, however, only known in 

 the animal kingdom, they are ordinary sperm oil and arctic 

 sperm oil. 



Among the better-known vegetable waxes may be men- 

 tioned : — 



{a) Carnauba Wax obtained from Coper nicia cerifera ; this 

 wax contains ceryl and myricyl alcohols, and two acids, 

 cerotic acid Co,;Hj^o02, and carnaubic acid C24H4J-O2, together 

 with a hydroxy-acid of the formula C21H42O3. 



{h) Pisang Wax obtained from the leaves of Cera musae is 

 the pisangceryl ester of pisangcerylic acid. 



The following are some of the more important waxes of 

 animal origin : — 



Wool wax, better known as wool fat or lanolin (which is 

 rich in cholesterol), beeswax, spermaceti, and Chinese insect 



PHYSICAL AND CHEMICAL PROPERTIES OF WAXES. 



Waxes are soluble in all the ordinary fat solvents such as 

 benzene, ether, chloroform, etc., though they are rather less 

 .soluble than the fats. 



Being free from glycerides the waxes, when heated, give 

 no smell of acrolein ; they do not become rancid like the fats, 

 and are less easily hydrolysed, but they can be decompo.sed 

 by prolonged heating with alcoholic potash. 



