THE SEPARATION OF ISOLINOLEIC ACID FROM HYDROGENATED LINSEED OIL BY CHROMATOGRAPHIC METHODS

When linseed oil or other oils containing linolenic acid are hydrogenated, an isomeric linoleic acid (isolinoleic acid) is formed. Its concentration increases to a maximum, then decreases as hydrogenation proceeds. In view of the possible relationship of this acid to "flavor reversion", its separation in pure form has been investigated. Concentrates of isolinoleic acid or its methyl ester were obtained from partially hydrogenated linseed oil by crystallizing a large proportion of the more saturated acids or methyl esters from a solvent at low temperatures. Further fractionation of such concentrates by chromatographic methods was investigated. Silica gel was found to be better for the purpose than either activated alumina or activated carbon. Methyl isolinoleate was adsorbed more firmly on the silica gel than the less unsaturated esters, which were eluted by means of large volumes of hexane. Subsequent elution with chloroform removed the methyl isolinoleate.