Kinetics And Mechanism Of Oxidation Of Amine Compounds By Potassium Ferrate (Ⅵ)

In this paper the kinetics of oxidation of amine compounds by potassium ferrate(VI)have been studied spectrophotometrically under alkaling condition. Throughout theexperiments, optimal conditions for running the reaction were determined, the effects ofreductant concentration, alkalinity and temperature on reaction rate (kobs) were summed up,from which the activation center was deduced, and a plausible reaction mechanism was putforward. The rate constants of the speed control step under different temperatures and theactivation parameters at298.2K were calculated. The theoretical value of rate constants fit thetest value very well which proves the veracity of the mechanism.The results show first order dependence on potassium ferrate (VI) and on each reductant.The observed rate constant (kobs) decreases with the increase of [OH-], and the reaction ratehas a negative fraction order with respect to [OH-], which indicates that there is a balance of[OH-] generation before the speed-control step. Meanwhile, we find that the main existedform of potassium ferrate is FeO42-in alkaline medium, and the concentration of HFeO4-isvery small. However, it is easy for HFeO4-to form a six-membered ring complex with thereductant in the presence of a hydrogen atom. The formed complex has higher activitytowards anion. Therefore, we consider the reaction takes place through HFeO4-, and theresults deduced tested the theory.With the help of unceasing research on transition metal complexes with unusualoxidation states, scientists found that they have vast application prospects, of which Fe (VI) isthe most important, for it plays a tremendous role in wastewater treatment. Therefore, to studyits kinetics and mechanism in redox reactions is imperative. The study of reaction mechanismin this paper provides an effective theoretical basis for reaction kinetics, and can serve as areference value to the development of coordination chemistry theory.