Kinetics of Oxidation of Aromatic Amines by Iron(III)-2,2'-Bipyridyl Complex

Department of Chemistry, Andhra University, Waltair

Manuscript received 19 October 1978, revised 3 July 1979, accepted 18 October 2979

Kinetics of oxidation of \(p\)-toluidine, \(m\)-toluidine and \(p\)-chloroaniline by iron(III)- 2,2'-bipyridyl complex have been investigated spectrophotometrically. The reaction obeys first order kinetics both in iron(HI) and the amine. A plot of 1/k₁ versus 1/[2,2'-bipyridylp]² is a straight line leaving a positive intercept on the 1/k₁-axis in each case, showing that 1 : 2 complex of iron(III) and 2,2'-bipyridyl is the active oxidizing species. Hydrogen ion was found to inhibit the reaction. A plot of 1/(k [H⁺]) versus [H⁺]² was found to be a straight line, making a positive intercept on the 1/k₁-axis. Bisulphate ion has also been found to inhibit the reaction. The equilibrium constant of the complex formation and the activation parameters were evaluated. A suitable mechanism has been proposed.