OF THE SO-CALLED EL^OMARGARIC ACID. S 



of the Other double bond no definite conclusion can be drawn 

 at present ; but in view of the fact that many unsaturated acids, 

 which give azelaic acid C02H(CH2)7C02H, on oxidation, such 

 for example as oleic acid and stearolic acid, contain the group 

 =CH(CH2)7C02H or =C(CH2)7C02H, it appears probable that it is 

 on that side of the middle double bond which is further removed 

 from the carboxyl group. The result of the action of aniline upon 

 elœomargaric acid, as described further on, favours this view. 



Experimental. 



Oxidation of elœomargario acid ivith potassium 2^6'ï"ffïcinff(f'nate. 



Following the method of oxidation described by Doebxer 

 (loc. cit.), 10 gr. of elaeomargaric acid was dissolved in caustic 

 potash suflScient for its neutralisation, diluted with water to 2 

 litres, and cooled to 2-3°. To this solution, 18 gr. of potassium 

 permanganate dissolved in 2 litres of water and cooled to 2-3° 

 was gradually added. After standing for 3 hours the precipitate 

 of manganese dioxide was filtered off, and the filtrate concentrated 

 to è litre and acidified with hydrochloric acid, when a brown 

 percipitate was formed, which was collected and recrystallised 

 several times from alcohol. In this manner, a white crystalline 

 substance of m. p. 130° was obtained, which, from the deter- 

 mination of the acid equivalent by means of standard baryta 

 water, proved to be dihydroxystearic acid. 



The filtrate from the impure dihydroxystearic acid was 

 rendered slightly alkaline w'ith ammonia, and calcium chloride 

 added, when a white precipitate was formed. This apparently 

 consisted of calcium oxalate, and no tartaric acid could be 

 detected. 



