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Further studies on the isomerization of polyunsaturated fatty acids by potassium tertiary butoxide
Author(s) -
Sreenivasan B. S.,
Brown J. B.
Publication year - 1958
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/bf02672660
Subject(s) - polyunsaturated fatty acid , chemistry , isomerization , potassium , linolenic acid , linseed oil , organic chemistry , linoleic acid , fatty acid , catalysis
Summary A temperature and time study revealed that the best conditions for the isomerization and estimation of polyunsaturated acids are heating in a sealed tube for 2 hrs. at 140° with potassium‐t‐butoxide in t‐butanol. Under these conditions conjugation of linolenic and arachidonic acids appears to have attained completion. With linoliec acid a higher degree of conjugation than by other methods and a shift of peak to lower wavelength (231–232 mμ) are observed. Extinction coefficients obtained by this method for isomerized pure linoleic (k 232 , 98.0) and linolenic (k 268 , 138.4) acids are the highest so far reported. Ultraviolet and infrared examination of the conjugated trienes isolated from isomerized linolenic acid concentrate showed that, under these conditions, trienes similar to both alpha‐ and beta‐eleostearic acids are produced. Analyses of samples of oils for component polyunsaturated acids, by this method, compare well with those by other methods. The presence of small amounts of a tetraenoic acid in linseed oil is noted.