Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6493075 | Journal of Photochemistry and Photobiology A: Chemistry | 2011 | 8 Pages |
Abstract
The quenching kinetics of superoxide (O2â) in water/oil (w/o) interface region of Aerosol OT reversed micelle has been investigated with a transient absorption method. Photodecomposition of α-tocopherol by 266 nm laser light in the presence of O2 produced O2â together with the tocopheroxyl radical (Toc). The subsequent reaction between Toc and O2â occurred in the time region of 1-150 μs after the photoexcitation. There, O2â kinetics could be traced by monitoring the Toc absorption. In an Aerosol OT reversed micelle solution containing vitamin C (VC), VC would be located in water droplets inside the reversed micelle and would react with both Toc and O2â at the w/o interface around the reversed micelle. The Toc decay in the time region of 1-150 μs was accelerated by addition of VC, suggesting that the O2â quenching by VC progressed as well as the Toc quenching by VC. From a numerical simulation with treating the simultaneous rate equations for Toc concentration by Runge-Kutta method, the rate constant for the O2â quenching by VC could be estimated to be 6.9 Ã 107 Mâ1 sâ1. This value is much larger than the corresponding value reported in homogeneous water solution, suggesting that the O2â quenching by VC indeed occurred at the w/o interface of the reversed micelle.
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Authors
Keishi Ohara, Akihiro Ikeda, Shin-ichi Nagaoka,