362 



Journal of Agricultural Research 



Vol. XIII, No. 7 



Fittig (1-5) has shown that unsaturated acids with the double bond 

 in jSt, or 9-10 position, as in oleic acid, may undergo intramolecular 

 changes on boihng with caustic alkali, forming an a-i3, or 2-3 acid, which 

 on fusion with alkali, according to Varrentrapp (9, p. 209-215) and Moli- 

 nari (6, p. 293), splits into acetic and another saturated acid. 



CH3.(CH2)7.CH : CH.(CH2)7.COOH=CH3.(CH2)h.CH : CH.COOH 



9-10 oleic acid a-/? or 2-3 oleic acid. 



CH3.(CH2)h.CH : CH.COOH+2 KOH=CH3.(CH2)h.COOK+CH3COOK+H2 



palmitate acetate. 



Schrauth (7) confirmed the reaction and claimed further that in general 

 for each double bond two carbon atoms are split off in the form of acetic 

 acid. Different authorities (5, p. 353-354) have shown that the unsatu- 

 rated (liquid) acids of olive oil consist principally of oleic acid with a 

 smaller amount of linolic acid. 



After considering the high content of unsaturated acids and their 

 possible decomposition as described, one might suggest as a tentative 

 hypothesis that the increase in saponification number was due to the 

 formation of a a-^, or 2-3 acid, from the action of air or more effectively 

 from air-light, which on boiling with alcoholic potash broke down into 

 acetic and palmitic acids. Either oleic or linolic acid might be affected, 

 although the latter is unquestionably less stable and therefore more 

 likely to undergo molecular change. Both oleic and linolic acids, on 

 breaking down into acetic and palmitic acids, double their alkali-con- 

 suming power; therefore, the increase in saponification number would 

 be directly proportional to the amount of acid affected. The statement 

 made by Schrauth that one molecule of acetic acid splits off for each 

 double bond, appeared untenable for linolic acid in this connection. The 

 neutralization number of oleic acid is 198.709 and of linolic acid 200.138. 

 Assuming that a-/3, or 2-3 oleic acid and linolic acid, after molecular 

 rearrangement have no appreciable iodin numbers, as determined by 

 Wijs solution, the writers obtained the following results for the sixth 

 year of the experiment (Table VII) : 



Table VII. — Character of the decomposition of the olive oil {1916) 



Series. 



Conditions of the experiment. 



Air 



Air-light 



Air-moisture 



Air-light-moisture 



Increase 



in sa- 

 ponifica- 

 tion 

 number. 



4.72 

 13-04 



4-13 

 13.21 



Equiva- 

 lent 



to oleic 

 acid. 



Per cent. 



2-375 

 6.562 

 2. 078 

 6.648 



Equiva- 

 lent 

 loss in 

 iodin 

 niunber. 



2-135 



5-976 



Equiva- 

 lent to 

 linolic 

 acid. 



Per cent. 



2-358 

 6.516 

 2. 064 



6. 600 



Equiva- 

 lent 

 loss in 

 iodin 

 number. 



Actual 



loss in 



iodin 



number.' 



4.270 

 II. 800 



3-738 

 11.952 



3-85 



3-99 

 11.68 



1 See Table VIII. 



