Peroxy Acid Oxidations. I. A Kinetic and Mechanistic Study of Oxidation of Acetylacetone by Peroxomonophosphoric Acid and Hydrogen Peroxide in Alkaline Medium

Article abstract of DOI:10.1246/bcsj.60.3391

The kinetics of oxidation of acetylacetone by peroxomonophosphoric acid and hydrogen peroxide have been investigated in the pH range 8-13.7.The oxidations by peroxomonophosphoric acid at 308 K and I=0.6 mol dm^-3 follow the rate expressions, (i) in the pH range 8-10.63, where k₁=1.96 dm³ mol^-1 s^-1 and k₂=0.177 dm³ mol^-1 s^-1, and (ii) in the pH range 11.5-13.7, where k₃=30.4 dm³ mol^-1 s^-1 and k₆ ca. 0.The rate law for hydrogen peroxide oxidations in the pH range 9.2-13 at 308 K and I=0.1 mol dm^-3 is given by, the k₇ and k₁₀ values being 0.393 dm³ mol^-1 s^-1 and 0.143 x 10^-2 dm³ mol^-1 s^-1 respectively.A and A^- represent the diketo and enol form of acetylacetone respectively.The kinetic data and activation parameters are consistent with nucleophilic attack by peroxo species on both diketo and enol form of acetylacetone followed by oxygen-oxygen bond fission.