Abstract
The kinetics of oxidation of DL-Aspartic acid (Asp) by N-bromophthalimide (NBP) was studied in the presence of sodium dodecyl sulfate (SDS) in acidic medium at 308 K. The rate of reaction was found to have first-order dependence on [NBP], fractional order dependence on [Asp] and inverse fractional order dependence on [H+]. The addition of reduced product of the oxidant, that is, [Phthalimide] has decreased the rate of reaction. The rate of reaction increased with increase in inorganic salts concentration, whereas a change in [Cl−], ionic strength of the medium and [Hg(OAc)2] had no effect on the oxidation velocity. The rate of reaction decreased with a decrease in dielectric constant of the medium. COOH-CH2-CN was identified as the main oxidation product of the reactions. The various activation parameters have been computed. A suitable reaction mechanism consistent with the experimental findings has been proposed. The micelle-binding constant has been calculated.
Acknowledgments
Y. R. Katre and G. K. Joshi thank the University Grants Commission, New Delhi for Minor Research Project & Rajiv Gandhi National Research Fellowship, respectively.
Notes
Solution conditions: [NBP] = 1 × 10−4 mol dm−3, [Asp] = 1 × 10−3 mol dm−3, [H+] = 5 × 10−3 mol dm−3, [SDS] = 8.3 × 10−3 mol dm−3, [Hg++] = 2 × 10−4 mol dm−3, CH3COOH = 50%.
Solution conditions: [NBP] = 1 × 10−4 mol dm−3, [Asp], [Ser], and [Ala] = 1 × 10−3 mol dm−3, [Gly] = 5 × 10−4 mol dm−3, [H+] = 5 × 10−3 mol dm−3, [SDS] = 8.3 × 10−3 mol dm−3, [Hg++] = 2 × 10−4 mol dm−3, CH3COOH = 50% and (40% for [Gly]).
a Literature value for SDS at 25 °C = 8.1 × 10−3 mol dm−3. Solution conditions: [NBP] = 1 × 10−4 mol dm−3, [Asp] = 1 × 10−3 mol dm−3, [Hg++] = 2 × 10−4 mol dm−3, [H+] = 5 × 10−3 mol dm−3, [SDS] = 8.3 × 10−3 mol dm−3, [CH3COOH] = 50%.