Mechanism and Kinetics of the Photocatalyzed Oxidation of p-Phenylenediamines by Peroxydisulfate in the Presence of Tri-2,2'-bipyridylylruthenium(II)

Article abstract of DOI:10.1021/j100062a026

The autocatalytic oxidation of p-phenylenediamines with peroxydisulfate can be strongly enhanced by irradiation in the presence of tri-2.2'-bipyridylylruthenium(II).Ru(bpy)₃²⁺ acts as photosensitizer and photocatalyst.First, Ru(bpy)₃³⁺ is formed by quenching excited Ru^*(bpy)₃²⁺ with S2O8^2-.Then the ruthenium(III) complex oxidizes p-phenylenediamine.The resulting Ru(bpy)₃²⁺ can start the cycle again.The photocatalytic oxidation of N,N-diethyl-p-phenylenediamine as well as the dark reactions were studied with stopped-flow techniques.The mechanism of this complex reaction is discussed in detail.