CLASSIFICATION AND STRUCTURE OF FATTY ACIDS 23 



acid not possessed by linolenic acid. The structural formula for elaeo- 

 stearic acid was a matter of dispute until Boeseken and Ravenswaay^^-''^ 

 showed that it contains three ethylenic linkages, as ^vas indicated by the 

 high molecular refraction and the fact that it reacts with more than two 

 molecules of hydrogen. These workers indicated that the acid is 9,11,13- 

 octadecatrienoic acid, which is represented by the formula, CH3(CH2)3CH:- 

 CHCH : CHCH : CH(CH2)7COOH. This structure was later confirmed by 

 Eibner and Rossmann.^^ 



Elaeostearic acid makes up over 94% of the total fatty acids in Florida 

 tung oil,^^ while values of 74.5 to 76.7% have been reported for China tung 

 Qi|57,5s j^jj(^ 70.5% for Japanese tung oil.^^ It is also a major component 

 of bagilumbang {Aleurites trisperma) nut oil,^" and essang {Ricinodendron 

 africanum Miiller) seed oil.®^ Elaeostearic acid is not a normal constituent 

 of animal fats. However, when it is fed to animals, it may be stored in the 

 depot fats, where it has been identified by its spectroscopic absorption. 

 Appai'ently, the positions of the double bonds cannot be caused to shift to 

 those of linolenic acid in the animal body, since elaeostearic acid, in con- 

 tradistinction to linolenic acid, is entirely ineffective as a source of the es- 

 sential fatty acids.^- 



Eight geometrical isomers are possible in the case of elaeostearic acid, as 

 is the case with linolenic acid. However, the natural compound, a-elaeo- 

 stearic acid, has in all probability an a\l-cis configuration.^^ Although most 

 of the mono- and polyethenoid acids are liquid, the two common isomers of 

 elaeostearic acid (a and /3) are solids melting at 48-49°C. and 71 °C., re- 

 spectively. The higher melting point over that of linolenic acid, which 

 melts at — 11°C., has been attributed to the arrangement of the double 

 bonds in conjugated position. /3-Elaeostearic acid is a natural cis-trans 

 isomer. Although the a-isomer can be easily converted to the /3-form by 

 light, heat, or such catalysts as iodine or sulfur, the opposite change can- 

 not be effected. 



" J. Boeseken and H. .J. Ravenswaay, Rec. trav. chim., 44, 241-243 (1925). 



^^ J. Boeseken and H. .J. Ravenswaay, Verslag. Akad. Wetenschap. Amsterdam, 34, 

 204-207 (1925); Proc. Acad. Sci. Amsterdam, ;?<§, "386-389 (1925). 



« A. Eibner and E. Rossmann, Chem. Umschau, 35, 197-198 (1928); Chem. Abstr., 22, 

 4839 (1928); cited by A. W. Ralston, Fatty Acids and Their Derivatives, Wiley, New York, 

 1948, p. 138. 



5« R. S, McKinney and G. S. Jamieson, Oil & Soap, 12, 92-93 (1935). 



" A. Steger and J. Van Loon, /. Soc. Chem. Ind., 47, 361-363T (1928). 



58 H, P. Kaufmann and J. Baltes, Ber., 69, 2676-2679 (1936). 



59 R. S. McKinney and G. S. Jamieson, Oil & Soap, I4, 2-3 (1937); Chem.. Abst., 31, 

 1641 (1937). 



«o G. S. Jamieson and R. S. McKinney, Oil & Soap, 12, 146-148 (1935). 

 8' A. Steger and J. Van Loon, Rec. trav. chim., 54, 988-994 (1935). 

 «2 G. O. Burr, M. M. Burr, and E. S. Miller, J. Biol. Chem., 97, 1-9 (1932). 

 "E. Rossmann, Chem. Umschau, 39, 220-224 (1932): Chejn. Abst., 27, 702-703 

 (1933). 



