Micellar Effect on the Oxidation of L-sorbose by Imidazolium Fluorochromate in the Presence of Sodium Dodecyl Sulfate in a 50% (v/v) Aqueous Acetic Acid Medium—a Kinetic and Mechanistic Study

The present work examined the micellar effect of sodium dodecyl sulfate (SDS) on the kinetics of L-sorbose by imidazolium fluorochromate (IFC) oxidant in a 50% (v/v) aqueous acetic acid (AcOH) medium with a consistent ionic strength under the conditions [L-sorbose] \( \gg \) [IFC] at 303 K. Perchloric acid was used as the reaction mixture’s primary source of hydrogen ions. The reaction depicted a unit-order dependence on [IFC], [L-sorbose], and [HClO₄]. The effect of sodium perchlorate salt and acrylonitrile were also studied. The oxidation rates decreased with an increase in the dielectric value (D) of the reaction medium, and the outcomes were in accordance with the Amis (\(\log {{k}_{1}}\) and 1/D) and Kirkwood plots (\(\log {{k}_{1}}\) and (D – 1)/(2D + 1)). The reaction showed significant catalysis even before reaching the critical micelle concentration (CMC). However, the observed rate constants stabilized at higher SDS concentrations exceeding the CMC. Piszkiewicz’s cooperativity model was employed to describe the surfactant catalysis. The binding constant (K_D), rate constants, cooperativity index (n), and various thermodynamic parameters in the presence of SDS were evaluated. The products were identified as the lactone of C₅-aldonic acid and formaldehyde. Based on the observed findings, a theoretical mechanistic pathway was suggested.