THE PROBABLE IDENTITY OF α- AND β-LINOLEIC ACIDS

Abstract

Preliminary to a study of the glycerides of cottonseed oil, it was found necessary to prepare pure linoleic acid for the synthesis of certain glycerides.The only method available for the preparation of this acid in the quantity and degree of purity desired involved the bromination of free acids of an oil rich in linolcic acid and subsequent reduction of the crystalline tetrabromostearic acid with zinc.However, some doubts have been expressed as to whether linoleic acid thus prepared is identical with the natural acid in the oil, since it has been repeatedly noted that, besides the crystalline bromide, a liquid bromine addition compound is formed.This observation led Bedford (1) to suggest that two isomeric linoleic acids existed.To differentiate the two forms, he designated as a-' the crystalline bromide and its regenerated linoleic acid; as /3-, the liquid bromide and its regenerated linoleic acid.Although this suggestion has been given support and credence by some authors, others have held the opinion that only one geometrical configuration of linoleic acid exists.If the latter view is correct, the a-and /3-tetrabromides must be regarded aa racemic isomers, which upon reduction with zinc should regenerate the same linoleic acid.