The oxidation of 2,4,6-trichlorophenol (TCP) to 2,6-dichloro-1,4-benzoquinone (DCQ) by hydrogen peroxide using iron(III) meso-tetra(4-sulfonatophenyl) porphine chloride, Fe(TPPS)Cl, as a catalyst was studied with stopped-flow UV-vis spectrophotometry and potentiometry using a chloride ion selective electrode. The observations are interpreted by a three-step kinetic model: the initial reaction of the catalyst with the oxidant (Fe(TPPS)+ + H2O2 → Cat′) produces an active intermediate, which oxidizes the substrate (Cat′ + TCP → Fe(TPPS)+ + DCQ + Cl-) in the second step. The third step is the transformation of the catalyst into a much less active form (Cat′ → Cat″) and is responsible for the unusual kinetic phenomena observed in the system.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry