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Hydrogenation of linolenate. VII. Separation and identification of isomeric dienes and monoenes
Author(s) -
Sreenivasan B.,
Nowakowska Janina,
Jones E. P.,
Selke E.,
Scholfield C. R.,
Dutton H. J.
Publication year - 1963
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/bf02654738
Subject(s) - chemistry , double bond , cis–trans isomerism , crystallization , countercurrent distribution , isomerization , linolenate , organic chemistry , fatty acid , chromatography , catalysis
Isomeric dienes and monoenes produced by partial hydrogenation of linolenic acid have been separated by the combined use of low‐temp crystallization and countercurrent distribution. Cis, trans dienes have been separated from cis, cis dienes. Cis, cis conjugatable dienes have been partially separated from cis,cis nonconjugatable dienes. Dienes with one trans double bond were separated by gas chromatography into two groups: cis, trans and trans, cis . Individual positional isomers could not be separated. Cis ‐9 monoene was separated from cis ‐12, cis ‐15, and trans monoenes by low‐temp crystallization. Countercurrent distribution at 3,000 transfers only partially separated this mixture of cis ‐12, cis ‐15, and trans monoenes. The double bond in both cis and trans monoenes was found in all carbon positions, 7 through 16, showing for the first time that the 15, 16 bond of linolenic acid had moved away from the carboxyl. The major cis bonds remained at carbons 9, 12, and 15. Combination of countercurrent distribution fractions has produced samples containing 95% cis, cis dienes; 90% cis, trans or trans, cis dienes; 95% cis monoenes; and 90% trans monoenes.