What question did this study set out to answer?

To examine the kinetics and mechanisms of sulfadiazine degradation using potassium permanganate in acetate buffer.

April 14, 20260 citationsOpen Access

Computational and Kinetic Study for the Degradation of Sulfadiazine Sulfa Drug by Potassium Permanganate in Acetate Buffer

Key Points

To examine the kinetics and mechanisms of sulfadiazine degradation using potassium permanganate in acetate buffer.
Controlled degradation experiments using potassium permanganate in acetate buffer across various pH levels
Kinetic assays employing titrimetric and iodometric methods to determine reaction order and rate constants
Application of Arrhenius and Eyring equations for activation parameter assessment
Use of density functional theory to validate reaction mechanisms
Sulfadiazine degradation followed an overall second-order rate law
Higher degradation rates observed at lower pH, decreasing as pH increases from 3.76 to 8.80
Activation energy calculated as 26.853 kJ mol⁻¹ with a pre-exponential factor of 7.5486
Activation parameters at 40°C found to be 24.3 kJ mol⁻¹ for enthalpy, -191 J mol⁻¹K⁻¹ for entropy, and 84.1 kJ mol⁻¹ for Gibbs free energy

Abstract

AbstractObjective: This study thoroughly examined the kinetic, reaction process, and thermodynamic parameters for the degradation of sulfadiazine (SDZ) utilizing permanganate as an oxidizing agent in acetate buffer, encompassing degradation kinetics and mechanisms. Methodology: The degradation of sulfadiazine was examined under controlled conditions using permanganate as the oxidant in acetate buffer across a wide pH range. Kinetic experiments were performed using titrimetric and iodometric methods to ascertain reaction order, rate constant, and temperature dependence. Activation parameters were assessed by employing Arrhenius and Eyring equations. Reaction pathways and DFT calculations were utilized to examine electronic properties, activation barriers, and orbital interactions to substantiate the experimentally determined mechanism. Findings: Sulfadiazine (SDZ) degradation followed an overall second-order rate law under experimental conditions. A higher sulfadiazine (SDZ) removal rate is attainable at lower pH levels, with the removal rate diminishing as pH increases from 3.76 to 8.80. The activation energy was determined to be 26.853 kJ mol−1 and the pre-exponential factor is 7.5486 by using the Arrhenius equation. According to the observed results, a mechanism of the reaction has been proposed. Activation parameters such as enthalpy, entropy, and Gibbs free energy at 40°C were determined and found to be 24.3 kJ mol⁻¹, -191 J mol⁻¹K⁻¹, and 84.1 kJ mol⁻¹, respectively. Calculations utilizing density functional theory additionally validate the proposed reaction mechanism derived from kinetic measurements. Novelty: This study reports for the first time a comprehensive kinetic–mechanistic and DFT-supported investigation of sulfadiazine oxidation by potassium permanganate in acetate buffer, establishing a non-radical, charge-controlled electron transfer pathway. Unlike conventional Advanced Oxidation Processes(AOP)-based studies focused on degradation efficiency, this work elucidates medium effects, activation parameters, and selective S–N/C–S bond cleavage through integrated experimental–computational analysis, providing a new structure–reactivity perspective on sulfonamide oxidation. Keywords: Oxidation, Sulfadiazine, Potassium Permanganate, Acetate Buffer, Computational, Kinetic

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