Effect of surfactant micellization on the oxidation of mercaptobenzothiazole by bioinorganic molybdenum complex

Abstract

A spectrophotometric routine was used to study the effect of surfactant micellization on the oxidation of mercaptobenzothiazole (MBTZ) by bioinorganic molybdenum complex at 301 K and an absorption maxima of 560 nm. It follows an acid dependent oxidative pathway that is medium-sensitive. Charge distribution from the reaction species contributes to the redox retardation, resulting in a downturned primary salt effect with an unenhanced reaction rate. Alteration of the reaction medium with ethanol led to a lowering of oxidation time as the charge catalysis was promoted by a drop in the system permittivity. Likewise, the micellization of cetyltrimethylammonium bromide in the system increased the oxidation rate of the MBTZ due to the high impact of hydrophobic and ion interaction between the micelle and substrates. First order reaction kinetics was observed in the concentration of the redox partners and a 2:2 (complex: MBTZ) stoichiometry was obtained with the involvement of benzothiazyl radical, which resulted in the formation of benzothiazyl disulphide and a Mo2+ deactivated complex. The occurrence of counterion catalysis is pronounced in the reaction system. The standard enthalpy (31.52 ± 0.11 kJ mol−1) and Gibbs energy (74.54 ± 0.13) kJ mol−1 suggest that the process is endothermic dependent. The investigation of surfactant micellization effect on the reaction medium was quantitatively ascertained from the Piszkiewicz model of the complex interaction sequence.

Keywords

• Oxidation
• Micellization
• Binding affinity
• Kinetic model
• Molybdenum