Nafion chromium oxidants

Chromium(III) and cerium(IV) impregnated Nafion K (a perfluorinated sulfonic acid resin) were used as catalysts f°r the themoselective oxidation of a variety of alcohols using TBHP or NaBr03 as tlie oxy9en donor A e.g. 

To overcome the problems of toxicity and work-up associated with many inorganic oxidants, it would be advantageous to develop a catalytic supported oxidant. Towards this aim, chromium(III)-impregnated Nafion 511 (NAFK) has been used as a catalytic oxidant in the presence of t-butyl hydix)peroxide. This reagent gives good yields of ketones (80-100%), but unfortunately oxidation of primary alcohols leads to the formation of complex mixtures. 

Recently it has been reported that Nafion exchanged with Cr(III) or Ce(IV) provides useful catalysts for the oxidation of alcohols using t-butylhydroperoxide [139]. The exchange of protons was not quantitative but the residual content may well be inaccessible. The chromium based system yielded ketones cleanly ( 80%) from secondary alcohols, while... 

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