Kinetics and mechanism of oxidation of neutral α -amino acids by sodium N-chloro-p-toluenesulfonamide in acid medium

✍ Scribed by K. S. Rangappa; K. Manjunathaswamy; M. P. Raghavendra; N. M. Made Gowda

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 166 KB
• Volume: 34
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.10011

✦ Synopsis

Abstract

Kinetics of oxidation of α ‐amino acids, glycine, valine, alanine, and phenylalanine, by sodium N‐chloro‐p‐toluenesulfonamide or chloramine‐T (CAT) has been investigated in HClO~4~ medium at 30°C. The rate shows first‐order dependence on both CAT and amino acid concentrations and an inverse first‐order on [H^+^]. The variation of ionic strength and the addition of p‐toluenesulfonamide and Cl^−^ ion had no effect on the reaction rate. Decrease of dielectric constant of the medium by increasing the MeOH content decreased the rate. Rate studies in D~2~O medium showed the inverse solvent‐isotope effect of k~D~~2~O/k~H~~2~O=0.50. Proton‐inventory studies were carried out using H~2~O–D~2~O mixtures. The activation parameters have been computed. The proposed mechanism and the derived rate law are consistent with the observed kinetic data. An isokinetic relationship is observed with β=323 K, indicating enthalpy as a controlling factor. The rate of oxidation increases in the following order: Gly < Val < Phe < Ala. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 49–55, 2002