Photocatalytic Oxidation of Toluene to Benzaldehyde
and the small value of k6 (<1 M-1 s-1 28
make this path slow,
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)
but possibly still competitive with the bimolecular self-reactions
of the low concentrations of the radicals. The failure to observe
the hydroperoxide suggests either that reaction 6 is unimportant
or that the hydroperoxide is converted rapidly to PhCHO. The
latter process may be catalyzed by the uranium species present
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as judged by the derived value of kH, which assumes that only
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event.
We also consider a reaction of PhCH2OO• with UO2+, as we
proposed recently11 for several alkylperoxy radicals. The
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2+
regenerates UO2
.
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PhCH2OO• + UO2+ f PhCH2OOUO2
+8
H
+
2+
PhCHO + H2O + UO2 (7)
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At the present time the data are insufficient to select any one
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The results of a cursory study of the oxidation of other
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alkylperoxy radicals.31
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Acknowledgment. We thank Drs. J. H. Espenson, G. A.
Russell, P. J. Hansen, and W.-D. Wang for helpful discussions,
and Mr. Z. Zhu for assistance with some GC-MS experiments.
This work was supported by the U.S. Department of Energy,
Office of Basic Energy Sciences, Division of Chemical Sciences,
under Contract W-7405-Eng-82. An Ames Laboratory Directed
Research and Development Grant is gratefully acknowledged.
References and Notes
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(1) (a) Shilov, A. E. ActiVation of Saturated Hydrocarbons by
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Boston/Lancaster, 1984. (b) The ActiVation of Dioxygen and Homogeneous
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