The combination of ferrous salts with hydrogen peroxide in aqueous media produces hydroxyl radical, which is highly reactive and in the presence of organic substrates produces a wide range of hydrox-ylated products. Stable solutions of superoxide ion can be prepared in anhydrous dipolar aprotic solvents by the electrolytic controlled-potential reduction of dioxygen. The most convenient solvents are dimethyl sulfoxide, dimethylformamide, acetonitrile, or pyridine, and tetralkylammonium Perchlorates or tetrafluoroborates are appropriate inert supporting electrolytes. There have been many investigations and reviews of the reactivity of activated oxygen species with organic substrates. The electrochemical reduction of hydrogen peroxide in pyridine at a platinum electrode yields superoxide ion as the major product. Perhaps the best known and most commonly used method for the generation of hydroxyl radical is the reaction of ferrous ion with hydrogen peroxide in the Fenton process.