A comparative analysis of the kinetic oxidation of maltose by n- bromosaccharin in aqueous acetic acid with and without ctab

The kinetics of maltose oxidation by N-bromosaccharin (NBSA) was investigated in aqueous acetic acid medium under acidic conditions, with and without cetyltrimethylammonium bromide (CTAB), a cationic surfactant. Additionally, the Piszkiewicz model was utilized to elucidate the micellar effect. The reaction was studied at a constant ionic strength of 0.1 mol dm-3 (maintained using sodium perchlorate) and at a temperature range of 313.15-343.15 K. Under pseudo-first-order conditions ((maltose) ≫ (NBSA)), the reaction followed first-order kinetics with respect to (NBSA) and showed a fractional-order dependence on (maltose). Reactions were conducted in 10% v/v, 20% v/v and 30% v/v acetic acid-water mixtures, and the pH was maintained using perchloric acid. The rate increased with rising acetic acid content, indicating enhanced reactivity of protonated oxidant species. In the absence of CTAB, the oxidation proceeded at a moderate rate, while the addition of CTAB (0–5 × 10⁻3 mol dm⁻³) led to a significant enhancement, confirming micellar catalysis. A break in the plot of rate constant versus (CTAB) corresponded to the critical micelle concentration (CMC), indicating the transition to micelle-assisted oxidation. Under various thermal conditions the Arrhenius activation energy along with various thermodynamic activation characteristics are evaluated. A mechanistic pathway is proposed involving the electrophilic attack of NBSA on maltose, facilitated by the microenvironment of the CTAB micelles. The study demonstrates that CTAB significantly enhances the oxidation rate by modifying the reaction pathway, which underscores the utility of surfactant systems in tuning the kinetics of carbohydrate oxidation.