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

Abstract

AbstractThe ruthenium (III) catalyzed redox reaction of paracetamol with hexacyanoferrate (III) in an acidic medium has been investigated. The reaction shows fractional order dependence respecting paracetamol and first‐order dependence respecting the oxidant and ruthenium (III). It is enhanced by medium according to the equation kobs=a+b[H+]. The activation and thermodynamic parameters of the reaction have been estimated using the Arrhenius and Eyring equations. The oxidation product of paracetamol has been identified as quinone oxime through spectral analysis. Furthermore, the reaction has been examined in nine various organic solvents, and the solvents effect has been investigated by Taft's and Swain's multiparametric equations. The rate constants have been found to correlate well with Kamlet‐Taft's solvatochromic parameters (α, β, π*). The reaction constants have been found to be negative, suggesting that the reactivity is influenced mainly by the solute‐solvent interactions. On the basis of kinetic results, a plausible reaction mechanism has been proposed. The proposed mechanism is reinforced by additional evidence from density functional theory (DFT) computations conducted at b3lyp/6‐311*G (d,p) level, which demonstrate that the activation energy barriers align with the reactivity trend observed in the kinetics experiments. Therefore, these computational results provide further support for the proposed mechanism.