An Experimental and Computational Kinetic Evaluation of Silver (I)-Catalyzed Oxidation of p-Chlorophenol by Hexacyanoferrate (III): Exploring the Mechanistic Pathway

The present investigation delves into the redox reaction between p-chlorophenol (p-CP) and hexacyanoferrate (III) [HCF (III)], catalyzed by Ag (I) within an alkaline environment. Findings reveal a first-order dependence on both p-CP and the oxidant, also the reaction rate showcases a first-order respect towards Ag (I), further amplified by the medium as per the equation kobs = a + b[OH-]. Interestingly, the ionic strength remains unchanged throughout the reaction, exerting no discernible effect on the reaction rate. Evaluation of activation and thermodynamic parameters utilizes the Arrhenius and Eyring equations. Spectral analysis identifies the oxidation product of p-CP as hydroquinone. Exploration extends to various organic solvents, with their effects scrutinized through Taft's and Swain's multiparametric equations. Notably, the rate constants fall to correlate satisfactorily with Kamlet-Taft's solvatochromic parameters (α, β, π*). Building upon kinetic findings, a plausible reaction mechanism is proposed. This proposition gains substantial reinforcement from additional evidence derived through Density Functional Theory (DFT) computations conducted at the b3lyp/6-311*g (d,p) level. These computations reveal activation energy barriers consistent with observed reactivity trends in kinetics experiments, thereby solidifying support for the proposed mechanism.