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Study on the effect of antioxidants in the autoxidation of methyl nonconjugated octadecadienoates
Author(s) -
Fukuzumi Kazuo,
Ikeda Nobuo
Publication year - 1969
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/bf02541209
Subject(s) - cis–trans isomerism , chemistry , induction period , autoxidation , double bond , peroxide , antioxidant , structural isomer , conjugated system , medicinal chemistry , stereochemistry , organic chemistry , polymer , catalysis
Many studies have been published on the effect of antioxidants on unsaturated fatty acid esters but the differences of the effects of antioxidants on geometric isomers have never been investigated. In this study, methyl cis ‐9, cis ‐12‐octadecadienoate and its trans isomer methyl trans ‐9, trans ‐12‐octadecadienoate were used as methyl nonconjugated dienoates, and BHA, BHT, PG, NDGA, 4,4′‐dihydroxy‐3,5,3′,5′‐tetratert‐butyl diphenyl methane, L‐thyroxine sodium salt, a ‐tocopherol and sesamol were used, as antioxidants. The differences of the effects of antioxidants on both geometric isomers were investigated by determining the induction period using the weighing method. Also determined were the infrared and ultraviolet spectra, peroxide values, conjugated diene contents, isolated trans double bond contents and molecular weights for the controls and the samples containing antioxidants. The cis,cis isomer was more easily autoxidized and had a shorter induction period than the trans,trans form. By the end of the induction period, no isolated trans double bond forms in the cis,cis isomer, but a considerable amount of isolated trans double bond decreased in the trans,trans isomer. In general, the effects of antioxidants, except NDGA, on the cis,cis isomer were larger than the trans,trans form.