Kinetics of Oxidation of some Phenols by Iron(III)-1 ,1 0- Phenanthroline Complex

Department of Chemistry, Andhra University, Waltair

Manuscript received 17 March 1977, revised 29 August 1977 Accepted, 11 October 1977

Kinetics of oxidation of phenol, m-cresol, p-cresol, p-bromophenol, p-chlorophe­nol have been investigated spectrophotometrically at 35°. The reaction obeys first order kinetics in iron(III) ; plots of 1/k₁ versus 1/[1,10-Phenanthroline]² and 1/k₁ versus 1/[Substrate] and 1/k₁ versus [HSO^-₄]² are straight lines with positive intercepts on the 1/k₁ axis in each case. The kinetic evidence is in favour of the formation of a mixed ligand complex of iron(III) with 1,10-Phenanthroline and phenol. The reaction gave a good Hammett plot with a p⁺ value of -1.6.