The Jones Reagent is a solution of chromium trioxide in diluted sulfuric acid that can be used safely for oxidations of organic substrates in acetone. The reagent can also be prepared from sodium dichromate and potassium dichromate. Jones Reagent is especially suitable for the oxidation of secondary alcohols to ketones and of primary alcohols to carboxylic acids and in a few cases to aldehydes (Jones Oxidation). Some alternative chromium reagents allow the selective preparation of aldehydes, such as PCC and PDC.
Although the reagent is very acidic, the substrate in acetone is essentially titrated with the oxidant solution and only very acid-sensitive groups are incompatible. For example esters, even tert-butyl esters, remain unchanged. The concentration of sulfuric acid can be decreased to minimize side reactions, although the oxidation power decreases too.
A full review of chromium-based reagents can be found in the book written by Tojo and Fernández (Oxidation of Alcohols to Aldehydes and Ketones, Springer Berlin, 2006, 1-97.).
Attention: Chromium (VI) compounds are toxic and must be handled with care.