Anion exchange resins chromic acid

Chromic acid also becomes a selective oxidant for die piqiaration of aldehydes and ketones whmi it is siq XHted on an anion exchange resin (Ambeilyst A-26 TaUe 16). The reaction appears to be gmeral and h lhly tolonnt of a wide range of solvoits, unlike many resin-based oxidations where the availability of the oxidant is critically dependent upon the nature of the solvent... 

The first regeneration of the strong base anion exchange resin with a near stoichiometric quantity of sodium hydroxide converts the loaded dichromate form of the resin to the chromate form whereafter it is able to efficiently take up chromic acid again. The anion column effiuent of sodium chromate may be cation exchanged across a strong acid resin in the hydrogen form to recover chromic acid ... 

Cainelli, G., Cardillo, G., Orena, M., Sandri, S. Polymer supported reagents. Chromic acid on anion exchange resins. A simple and practical oxidation of alcohols to aldehydes and ketones. J. Am. Chem. Soc. 1976, 98, 6737-6738. 

Chromic acid has been bound to commercial anion exchange resins as the CrO H" form by Cainelli et al. (23). This polymeric species was shown to be quite effective in the oxidation of primary and secondary alcohols to aldehydes and ketones in high yield. Overoxidation of aldehydes did not occur. 

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