Electron spin resonance studies. Part 61. The generation and reactions of the t-butoxyl radical in aqueous solution

Abstract

The t-butoxyl radical has been generated in aqueous solution from the reaction between Ti^III and Bu^tOOH in a flow system. Evidence is presented which indicates that, although the fragmentation of Bu^tO· to Me· and acetone is rapid under these conditions (k > 10⁶ dm³ mol^–1 s^–1), competing addition reactions (e.g. to vinyl ethers, furan) and abstraction reactions (with alcohols) can be characterized. Bu^tO· is shown to be electrophilic, like ·OH, in its reactions, but with prop-2-en-1-ol, unlike ·OH, it undergoes abstraction rather than addition. Changes in the behaviour of t-butoxyl at very low pH are attributed to the formation and reaction of the protonated counterpart Bu^tOH⁺˙.