Kinetics and mechanism of alkane hydroperoxidation with tert-butyl hydroperoxide catalysed by a vanadate anion

Abstract

tert-Butyl hydroperoxide oxidizes alkanes in acetonitrile at 60 °C if the soluble vanadium(V) salt, n-Bu₄NVO₃, is used as a catalyst. Alkyl hydroperoxides are formed as main products which decompose during the course of the reaction to produce the more stable corresponding alcohols and ketones. Turnover numbers (i.e. numbers of moles of products per one mole of a catalyst) attained 250. The kinetics and selectivity of the reaction have been studied. The mechanism proposed involves the formation of a complex between the V^V species and t-BuOOH (K₅ was estimated to be 5 dm³ mol⁻¹) followed by decomposition of this complex (k₆ = 0.2 s⁻¹). The generated V^IV species reacts with another t-BuOOH molecule to produce an active t-BuO˙ radical which attacks the hydrocarbon.