Anodically generated manganese(III) acetate for the oxidation of ? ? amino acids in aqueous acetic acid: A kinetic study

Abstract

Manganese(III) acetate was prepared by the oxidation of manganese(II) acetate in aqueous acetic acid by electrolytic method. The anodically generated Mn(III) species was characterised by spectroscopic and redox potential studies. Conditions for the study of kinetics of Oxidation ofα-amino acids by Mn(III) in aqueous acetic acid was investigated. Plots of log[Mn(III)] versus time for the first order process, or Mn(III) versus time for zero order process were nonlinear. The rate constants computed from [Mn(III)](1/2) versus time plots were independent of [Mn(III)]0 indicating that the reaction goes through competitive zero and first order path-ways in [Mn(III)]0. The kinetic order in [amino acid], [H(+)] and [Mn(II)] were found out. Effect of added anions like CH3COO(-), F(-), Cl(-) and ClO 4 (-) were investigated. Evidence for the transient existence of the free radical reaction intermediate is given. Dependence of reaction rate on temperature is explained and activation parameters computed from Arrhenius and Eyring plots. A mechanism consistent with the observed results is proposed and discussed.

Oxidation of L‐amino acids by metal ion (Mn3+) in sulfuric acid medium: Effect of nucleophilicity and hydrophobicity on reaction rate

“…Several studies have been reported on the kinetics of oxidation of AAs by various oxidants in different media [3,4]. Most of the previous kinetic investigations provide information about reaction mechanism, thermodynamic parameters, activation parameters [5], and oxidative reaction products.…”

Manganese(III) Oxidation of Alanine in Aqueous Ethanoic Acid Medium: A Kinetic and Mechanistic Study

“…[1,2] There are several reports of oxidation of various substrates by Mn(III) in acid solutions containing such salts as perchlorate, sulfate, acetate, and pyrophosphate. [7][8][9][10][11][12][13] A study of the kinetics and mechanism of oxidation of DL-Ala by Mn(III) in aqueous acetic acid solutions is reported here.…”

Manganese(III) Oxidation of L-Methionine in Aqueous Acetic Acid Medium: A Kinetic and Mechanistic Study

“…[1,2] There are several reports of oxidation of various substrates by Mn(III) in perchlorate, sulfate, acetate and pyrophosphate media. [7][8][9][10][11][12][13][14] Non-sulfur containing amino acids and amines usually undergo oxidation via deamination to the corresponding aldehydes. Since sulfur is a preferred site of oxidation, amino acids such as Met undergo oxidation to the corresponding sulfoxide or sulfone.…”