Primary and secondary alcohols are easily oxidized by a variety of reagents, including
chromium oxides, permanganate, nitric acid, and even household bleach (NaOCl, sodium
hypochlorite). The choice of reagent depends on the amount and value of the alcohol. We
use cheap oxidants for large-scale oxidations of simple, inexpensive alcohols. We use the
most effective and selective reagents, regardless of cost, for delicate and valuable alcohols.
Many of the traditional oxidants are based on chromium(VI) compounds. These chromium
reagents are highly toxic, and they are difficult to dispose of properly. Chemists are gradually
moving to less toxic oxidants. We will cover the traditional chromium reagents and
their uses, and then we will survey the more environmentally friendly alternatives.
Although this may seem like a bewildering array of oxidizing agents, all of them
have an element (Cr, Cl, I, or S) in a high oxidation state bonded to oxygen. Moreover,
they follow similar mechanisms, as illustrated by the reaction of hypochlorous acid
(HOCl, from household bleach), with a secondary alcohol: