Controlling Factors in the Rates of Oxidation of Anilines and Phenols by Triplet Methylene Blue in Aqueous Solution

Citations Over TimeTop 10% of 2015 papers

Abstract

Anilines and phenols are structurally similar compound classes that both are susceptible to oxidation by excited state triplet sensitizers but undergo oxidation by different mechanisms. To gain an understanding of the factors that control the rate of oxidation of anilines and phenols by triplet excited states, a kinetic study was performed on the oxidation of substituted anilines and phenols by methylene blue. The rate constants of one-electron transfer from anilines to triplet state methylene blue and their dependence on the reaction free energy are well fit to a Sandros-Boltzmann model. The observed rate constants are also well modeled when aniline oxidation potentials derived computationally are used. For phenols, the proton-coupled electron transfer rate constants were found to correlate primarily with O-H bond dissociation free energy and secondarily with phenol pKa. Rate constants for phenols could be modeled using computed bond dissociation free energies. These results provide a basis for predicting aniline and phenol oxidation rates, which could be valuable, for example, in assessing the likely persistence and fate of aniline- and phenol-based aqueous environmental pollutants.

Related Papers

• → Biodegradation Kinetics of Phenols in an Aerobic Biofilm at Low Concentrations(1991)27 cited
• → Bioconsumption of phenols from effluents(1998)
• Determination of Trace Amount of Phenol and Aniline by Fluorescence Spectrophotometry in Natural Water(2011)
• Wet Air Oxidation of Phenol,Nitrobenzene and Aniline in Wasterwater(2004)
• SIMULTANEOUS SEPERATION AND CONCENTRATION FOR MICRO PHENOL AND ANILINE BY DISTILLATION WITH ADDING SALTS(2000)