Cationic Surfactant-Based Catalysis on the Oxidation of Glutamic Acid by Bis-(2-pyridinealdoximato)dioxomolydate(IV) Complex

Abstract

A spectrophotometric routine was used to study the cationic surfactant-based catalysis on the oxidation of glutamic acid (GTA) by bis-(2-pyridinealdoximato)dioxomolybdate(IV) complex at 302 K and an absorption maxima of 560 nm. It follows an acid independent oxidative pathway that is medium-sensitive. Charge density from the reaction species contributes to the redox acceleration, resulting in an upturned primary salt effect with an enhanced reaction rate. Modifying reaction medium with ethanol led to a rise in the oxidation time as the charge catalysis was unsupported by a drop in the system permittivity. Likewise, the inclusion of cetyltrimethylammonium bromide in the system increased the oxidation rate of the GTA due to the high impact of hydrophobic and ion interaction between the micelle and substrates. First order reaction kinetics was observed in the redox partners’ concentration. A 1:1 (complex:GTA) stoichiometry was obtained with the involvement of aldehyde succinic radical, resulting in succinic acid and a Mo2+ deactivated complex. The occurrence of counterion catalysis is pronounced in the reaction system. The standard enthalpy (24.98 ± 0.03 kJ mol−1) and Gibbs energy (79.32 ± 0.05 kJ mol−1) suggest that the process is energy demanding. The investigation of surfactant-based catalysis in the reaction system was quantitatively ascertained from the Piszkiewicz model of the complex interaction sequence. Graphical Abstract: [Figure not available: see fulltext.]