Kinetics and mechanism of pyrogallol autoxidation

The kinetics of pyrogallol autooxidation has been studied by single-sweep oscillopolarography in Tris-HCl buffer soluton in the pH range 7.20 similar to 9.10. The reaction was first order to pyrogallol in the presence of excess dissolved O-2, The focus was put on pyrogallol autooxidation with products of semiquinone free radical and active oxygen. A mechanism was presented which explains the increase in rate with increasing pH by postulating that H2PYR- has a greater reactivity with dissolved O-2 than H3PYR. The derived rate law is in good agreement with the experimental observations, The paper also presented a new assay for superoxide dismutase and antioxidant activity of pharmaceuticals.