Trace metal ion catalysis; kinetics and mechanism of oxidation of metol by hydrogen peroxide in the presence of iron(III) sulphate in acid perchlorate

Abstract

The kinetics of oxidation of N-methyl-p-aminophenol (metol) by H20 2 in the presence of trace levels ofFe m have been studied in an HC104 medium. The reaction mechanism is complex and the catalytic role of Fe nl in the sulphato form is indicated. The following rate law accounts for the experimental observations: --d[HzO2]/dt = /<;in 4-K 1 K2 [metol] [H202] [Fe 3 +] (k 1 + kzl-metol] ) 1 + Kl[metol] + K~K2Emetol] [H202]where kiun is the initial rate for the uncatalysed reaction. The equilibrium constants K1 and K 2 are the formation constants for the complexes [Fe(metol)l 3+ and [Fe-(metol)(H202)] 3 +, respectively. The catalytic role of Fem is explained by considering a ternary complex in the transition state.

Experimental and Computational Kinetic Assessment of Ruthenium (III) Catalyzed Oxidation of Paracetamol by Hexacyanoferrate(III): A Mechanistic Pathway

“…HCF (III) is a potent one‐electron oxidant and has redox potential of 0.36 V. It can act as a proton or electron abstracting reagent in oxidation reactions. Many redox reactions have been carried out using HCF (III) in alkaline media with or without catalysts, such as those of sulfanilic acid, [18] crotyl alcohol, [19] formazans, [20] ascorbic acid, [21,22] and Tellurium (IV) [23] . HCF (III) has also been employed for the oxidimetric determination of both inorganic and organic compounds in both acidic and alkaline media [2,24] .…”