THE LECITHINS 415 



After drying, it can be pulverized. It is an amorphous product, but can 

 be obtained in crystalline form when prepared at low temperatures. No 

 melting points are ascertainable, even in the case of pure lecithin prepara- 

 tions, since the substance becomes bro\Mi and it is impossible to determine 

 when melting has occurred. 



Lecithin is soluble in the usual fat solvents such as chloroform, diethyl 

 ether, petroleum ether, carbon disulfide, carbon tetrachloride, benzene, 

 and alcohol, but it is not soluble in methyl acetate "^-^ or acetone. The 

 precipitation by acetone is rendered more difficult when fat is present. 

 In cliloroform and diethyl ether solution, precipitation is only about 50% 

 complete with acetone. ''*' However, the precipitation can be made com- 

 plete if a little saturated magnesium chloride solution is added to the 

 acetone." Lecithin can also be thrown out of ether solution by par- 

 aldehyde. "^ 



The solubility of the synthetic distearolecithin in various solvents is 

 given in Table 2. 



Table 2 

 Solubility of Synthetic Distearolecithin in Various Solvents at Low 



Temper.^tures" 



" H. Thierfelder and E. Klenk, Chemie der Cerebroside und Phosphatide, Springer, 

 Berlin, 19-30, p. 122. 



Synthetic distearolecithin was found to dissolve in aromatic solvents as 

 well as in high-boiling hydrocarbons. It is also readily soluble at room 

 temperature in amyl alcohol, ethyl and amyl acetates, carbon disulfide, 

 pyridine, chloroform, carbon tetrachloride, and dichlorohydrin ; on heating 

 it goes into solution in methyl, ethyl, and propyl alcohols, ethylene chloride, 

 glycolchlorohydrin, and acetic acid, but it is very difficultly soluble at room 

 temperature. It also dissolves in glycerol, but, like other natural lecithins, 

 it has been found to be practically completely insoluble in diethyl ether, 

 petroleum ether (60-70°C.), and acetone. 



« E. Winterstein and O. Hiestand, Z. physiol. Chem., 54, 288-330 (1907-1908). 

 68 J. Nerking, Biochem. Z., 10, 193-203 (1908). 

 " J. Nerking, Biochem. Z., 23, 262-269 (1909). 

 « E. A. Cooper, Biochem. J., 18, 948-950 (1924). 



