Products of stoichiometry of reaction of vitamin E with alkylperoxy radicals

Winterle, John S.; Dulin, David; Mill, Theodore

doi:10.1021/jo00177a021

Cited by 71 publications

(31 citation statements)

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“…2C). The quinones may consist of dimers or spirodimers [7,35]. The bands at 1655 and 1598 cm À1 are consistent with the formation of a spirodimer in tetradecane, similar to that formed in melt processing of vitamin E stabilised HDPE [7].…”

Section: Discussionsupporting

confidence: 65%

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Antioxidant effectiveness of vitamin E in HDPE and tetradecane at 32°C

Mallégol

Carlsson

Deschênes

2001

Polymer Degradation and Stability

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Vitamin E was found to be a very effective antioxidant both in a model, liquid alkane, (teradecane) and in HDPE when oxidations at close to room temperature were initiated with g-radiation. FTIR was used to follow changes in vitamin E in oxidising tetradecane and HDPE, even at very low concentrations of the antioxidant. Formation of isolated hydroperoxide groups as a direct result of the vitamin E-peroxyl radical reaction were clearly visible. Quinone products from vitamin E were formed during g-irradiation, but different quinones were formed depending on the vitamin E concentrations. Vitamin E quite effectively retarded the oxidation of HDPE during g-irradiation and so should be useful in polyethylene intended for radiation sterilisation, as packaging materials or medical devices. Crown

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Section: Discussionsupporting

confidence: 65%

“…1B and C), with formation of quinone products around 1684 cm À1 being more important in the 2% vitamin E solution. It is known that higher concentrations of vitamin E lead to increased concentrations of a-tocopherylquinone and the spirodimer [35].…”

Section: Discussionmentioning

confidence: 99%

Antioxidant effectiveness of vitamin E in HDPE and tetradecane at 32°C

Mallégol

Carlsson

Deschênes

2001

Polymer Degradation and Stability

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“…Alternately, the reactive tert-butoxyl can abstract hydrogen directly from the para methyl, a known reaction 30 . Some general trends were recognized and indicate how the product distribution depends on steric hindrance in the antioxidant 31 . If the antioxidant has bulky R groups (e.g.…”

Section: Reaction Products Of Antioxidants: α-Tocmentioning

confidence: 99%

Phenols as Antioxidants

Ross

Barclay

Vinqvist

2009

Patai's Chemistry of Functional Groups

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“…Each molecule of o!-tocopherol consumes thus two lipid free radicals and terminates the free-radical chain reaction. To elucidate the free-radical scavenging mechanism of tocopherols, the reaction products of tocopherols with lipid free radicals have been investigated (Winterle et al, 1984;Ham & Liebler, 1995, 1997Liebler et al, 1990Liebler et al, , 1991Liebler & Burr, 1992;Matsuo et a/, 1989;Yamauchi et al, 1989Yamauchi et al, , 1990aYamauchi et al, , 1990bYamauchi et al, , 1990cYamauchi et al, , 1993Yamauchi et al, , 1994Yamauchi et al, , 1995a). …”

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confidence: 99%

Vitamin E: Mechanism of Its Antioxidant Activity.

Yamauchi

1997

FSTI

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The antioxidant activity of vitamin E (a-tocopherol) during the peroxidation of unsaturated lipids has been reviewed based on its reaction products. Free-radical scavenging reactions of a-tocopherol take place via the a-tocopheroxyl radical as an intermediate. If a suitable free radical is present, a non-radical product can be formed from the coupling of the free radical with the a-tocopheroxyl radical. The reaction products of a-tocopherol with lipid-peroxyl radicals are 8a-(lipid-dioxy)-a-tocopherones which are hydrolyzed to a-tocopherylquinone. If the supply of oxygen is insufficient, a-tocopherol can trap the carbon-centered radicals of lipids to form 6-0-(lipidalkyl)-a-tocopherols. On the other hand, the dimer and trimer of a-tocopherol is formed by the bimolecular self-reaction of the a-tocopheroxyl radical in a reaction mixture containing a large amount of a-tocopherol. The other product-forming pathway yields isomeric epoxy-a-tocopherylquinones and their precursors, epoxyhydroperoxy-a-tocopherones, but the mechanism of this pathway remains unknown. The reaction products of other vitamin E compounds (7-and 6-tocopherols) during lipid peroxidation are almost the same as those formed from the a-tocopherol. The tocopheroxyl radicals of 7-and 6-tocopherols prefer to react with each other to form dimeric products that are still effective as antioxidants.

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Products of stoichiometry of reaction of vitamin E with alkylperoxy radicals

Cited by 71 publications

References 0 publications

Antioxidant effectiveness of vitamin E in HDPE and tetradecane at 32°C

Antioxidant effectiveness of vitamin E in HDPE and tetradecane at 32°C

Phenols as Antioxidants

Vitamin E: Mechanism of Its Antioxidant Activity.

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