Singlet oxygen and free-radical oxidation of polydienes and related problems with stabilization: Synergistic and antagonistic effects

Rabek, Jan F.; R�nby, Bengt; Arct, J.; Liu, Rixin

doi:10.1016/0047-2670(84)87051-3

Cited by 6 publications

(3 citation statements)

References 66 publications

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“…2,2,6,6-Tetramethyl-4-piperidone hydrochloride (TMPD) was obtained from Aldrich Chemical Company Inc. (Milwaukee, WI) and used as the detection reagent of singlet oxygen. ( 13 , 14 ) Rose bengal and riboflavin were obtained from Wako Pure Chem. Ind., Ltd. (Osaka, Japan) and used as photo-sensitizers to generate singlet oxygen and superoxide anion, respectively.…”

Section: Methodsmentioning

confidence: 99%

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Scavenging rate constants of hydrophilic antioxidants against multiple reactive oxygen species

Sueishi

Hori

Ishikawa

et al. 2014

J. Clin. Biochem. Nutr.

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Scavenging rate constants of eight hydrophilic antioxidants, including caffeic acid, chlorogenic acid, genistein, glutathione, N-acetylcysteine, rutin, trolox, and uric acid against multiple ROS, namely superoxide anion, hydroxyl radical, singlet oxygen, and alkoxyl radical were determined with the electron spin resonance method. Direct flash photolysis measurement of the second-order rate constant in the reaction of alkoxyl radical plus the spin trap 5,5-dimethyl-pyrroline N-oxide made it possible to evaluate scavenging rate constants in antioxidants. The magnitudes of scavenging rate constants were notably dependent on the character of each ROS and the overall rate constants were highest in hydroxyl radical scavenging and the lowest in superoxide anion. The highest scavenging rate constant against superoxide anion was obtained by chlorogenic acid (2.9 × 105 M−1 s−1) and the lowest was by N-acetylcysteine (5.0 × 102 M−1 s−1). For singlet oxygen, the highest was by glutathione (9.4 × 108 M−1 s−1) and the lowest was by uric acid (2.3 × 106 M−1 s−1). All other numbers are listed and illustrated. Redox potential measurements of the antioxidants indicated that the antioxidants are likely to react with superoxide anion and singlet oxygen through electron transfer processes.

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Section: Methodsmentioning

confidence: 99%

“…The reaction between singlet oxygen and TMPD to form a stable nitroxide radical was utilized to quantify singlet oxygen (Scheme 3). ( 13 , 14 )…”

Section: Methodsmentioning

confidence: 99%

Scavenging rate constants of hydrophilic antioxidants against multiple reactive oxygen species

Sueishi

Hori

Ishikawa

et al. 2014

J. Clin. Biochem. Nutr.

View full text Add to dashboard Cite

show abstract

“…Peroxides can be irradiated to reduce their stability—for example, peroxides can be photosensitized to become less stable—and homolyze to alkoxy radicals . Alkoxy radicals can be used for applications as initators of polymerizations . In homogeneous solution, alkoxy radicals were shown to form by triplet energy transfer from a sensitizer to a repulsive excited state in di‐ tert ‐butyl peroxide, thereby homolyzing the OO bond.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous photocatayltic deperoxidation with UV and visible light

Walalawela

Greer

2018

J of Physical Organic Chem

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A physical-organic study is described on the photodecomposition of dicumyl peroxide co-adsorbed with the sensitizers 4,4′-dimethylbenzil or chlorin e 6 on fumed (nonporous) silica. Dicumyl peroxide was decomposed by the heterogeneous photosensitization and monitored by the desorption of products acetophenone, 2-phenylpropan-2-ol, and α-methylstyrene using proton nuclear magnetic resonance and gas chromatography-mass spectrometry. Dicumyl peroxide and sensitizer were co-adsorbed on silica in 1:4 up to 200:1 ratios, with high peroxide destabilization occurring in ratios of about 10:1. This increased photodecomposition corresponded to sensitizer-peroxide distances of 6 to 9 Å. A Dexter triplet energy transfer mechanism is proposed that explains the short sensitizer and peroxide separation distances for higher peroxide O-O bond homolysis efficiencies on silica. This biphasic (gas/ solid) system can thus serve both to destabilize and stabilize a peroxide, which may be of practical use for the delivery of alkoxy radicals for bacterial disinfection.

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Mechanism of accelerated photofading of thioether anthraquinone dyes in styrene butadiene resins

Paine

Winnik

Bocking

1988

J of Applied Polymer Sci

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SynopsisMany anthraquinone dyes fade in visible light up t o 100 times faster in styrene butadiene copolymers than in polyester resins or polystyrene. A mechanistic investigation of the photofading of 1,5-dihydroxy-2,6-diisobutyl-4-thiophenylanthraquinone has established that the dye sensitizes formation of singlet oxygen, a very reactive species, which attacks the double bonds in the styrene butadiene, resulting in extensive chain cleavage and peroxide formation. The major process is the oxidation of the polymer, and the dye fading is a minor process whereby the dye is apparently attacked by polymeric peroxides. The mechanism appears to be general for anthraquinone dyes, especially those with thioether, amino, hydroxy, or double-bond functionality. Unfortunately the fading is unaffected by most antioxidant stabilizers: the best result achieved was a doubling of half-life with 1 wt% Spinuvex A-36. This is still insufficient to give colored styrene butadiene copolymer resins the intrinsic dye stability available in other polymers, rendering styrene butadiene unsuitable for applications requiring high photostability of anthraquinone dyes.

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Singlet oxygen and free-radical oxidation of polydienes and related problems with stabilization: Synergistic and antagonistic effects

Cited by 6 publications

References 66 publications

Scavenging rate constants of hydrophilic antioxidants against multiple reactive oxygen species

Scavenging rate constants of hydrophilic antioxidants against multiple reactive oxygen species

Heterogeneous photocatayltic deperoxidation with UV and visible light

Mechanism of accelerated photofading of thioether anthraquinone dyes in styrene butadiene resins

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