NATURAL "WAXES 363 



ported in jojoba oil, which has the properties of a wax. An unsaturated 

 hydroxy dibasic acid, shellohc acid, is found in shellac' Hydroxy mono- 

 basic acids have likewise been demonstrated in some waxes, for example, 

 aleuritic acid (9,10,16-trihydroxypalmitic acid) in shellac wax. 



d. Esters in Natural Waxes. The natural waxes contain chiefly the 

 alkyl esters of the higher aliphatic alcohols or sterols, and the fatty acids. 

 However, free alcohol and free fatty acid may occur, as well as small 

 amounts of hydrocarbons. Some of the commoner esters which are 

 known to occur in natural waxes are listed in Table 10. 



(3) Properties of Natural Waxes 



The waxes are relatively inert substances which, in most cases, are solids 

 at ordinary' temperatures. Some of them, such as beeswax, have the 

 property which permits them to be cut and shaped with ease. Beeswax 

 melts at a low temperature and it mixes well with coloring matter; the 

 consistency may be varied by admixture with inert material, or with fats or 

 oils. For this reason it has found wide application in the preparation of 

 wax figures and models. 



Although waxes respond to saponification, as do other esters, the reaction 

 is generally quite sluggish. According to Chibnall and collaborators, ^^ the 

 hj^drolysis is particularly difficult in the case of insect waxes, and special 

 procedures must be applied to obtain an effective breakdown. The diffi- 

 culty is due in part to the insolubility of one of the hydrolysis products — the 

 higher alcohol — in water, so that it is hard to determine when saponifica- 

 tion has been completed. Moreover, the subsequent separation of the 

 hydrolysis products is complicated b}^ unexpected solubility relations. 

 Although the higher alcohols can be readily separated from the water- 

 soluble potassium and sodium salts of the lower fatty acids by their extrac- 

 tion with organic solvents, the separation })ecomes more difficult with the 

 higher acids, since their sodium and potassium soaps do become appreciably 

 soluble in the fat solvents."^ The sodium and potassium salts of the C26 to 

 C36 alcohols dissolve to some extent in boiling acetone, and readily in boiling 

 benzene. On the other hand, the calcium soaps of these higher acids dis- 

 solve only sparingly in boiling acetone and alcohol, while they are only 

 slighth^ soluble in boiling benzene. They are insolulile in boiling diethyl 

 ether. Chibnall and co-workers'* have de^'eloped a satisfactory method for 

 the saponification of coccerin (a wax from Coccus cacti) which involves 

 saponification in a benzene-alcohol solution of potassium hydroxide fol- 

 lowed by a second saponification, by the use of sodium ethoxide, of the 

 portion still unsaponified. 



In spite of the relative stability of the ester linkage in the waxes, they 



»2s S. H. Piper, A. C. Chibnall, and E. F. Williams, Biochem. ./., 2S, 2175-2188 (1934). 



