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Homogenous catalytic conjugation of polyunsaturated fats by chromium carbonyls
Author(s) -
Frankel E. N.
Publication year - 1970
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/bf02541453
Subject(s) - linolenate , chemistry , conjugated system , dehydrogenation , catalysis , polyunsaturated fatty acid , chromium , medicinal chemistry , organic chemistry , yield (engineering) , fatty acid , polymer , materials science , metallurgy
Various arene‐Cr (CO) 3 complexes and Cr(CO) 6 are effective soluble catalysts for the conjugation of polyunsaturated fats. Methyl benzoate‐Cr(CO) 3 is one of the most active catalysts. The following conjugation levels were obtained: methyl linoleate, 65%; methyl linolenate, 45%; the polyunsaturates in soybean and safflower oils, 73%; and in linseed oil 48%. Conjugated dienes from linoleate were predominantly cis,trans in configuration. Their double bonds were distributed between C 5 and C 16 of the fatty acid chain. Hydrogenation and dehydrogenation are side reactions, which seem to limit the yield of conjugated dienes from methyl linoleate. A conjugation mechanism is proposed that involves allyl‐HCr(CO) 3 complexes as intermediates undergoing 1,3‐ and 1,5‐hydrogen shifts.