Role of Chloride in the Ruthenium(III) catalysed Oxidation of Amino Acids by Chloramine-T in Aqueous Perchloric Acid Medium
| Main Authors: | B. THIMME GOWDA, P. RAMACHANDRA |
|---|---|
| Format: | Article Journal |
| Bahasa: | eng |
| Terbitan: |
, 1990
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| Subjects: | |
| Online Access: |
https://zenodo.org/record/6204270 |
Daftar Isi:
- Department of Post-Graduate Studies and Research in Chemistry, Mangalore University, Mangalagangothri-574 199 Manuscript received 3 July 1989, revised 29 January 1990, accepted 7 May 1990 Kinetics of RuIII catalysed oxidations of several amino acids (AA) (glycine, alanine, valine, leucine, phenylalanine and serine) by chloramine-T in the presence of chloride ion have been studied in aqueous perchloric acid medium. All the amino acids except glycine show second order kinetics in [oxidant], fractional order each in [AA], [RuIII] and [Cl- ], and inverse fractional order in [H+], as compared to the second order dependences in [oxidant], first order in [AA], fractional order in [Cl-] and inverse first order in [H+], generally observed for uncatalysed oxidations. Variations in ionic strength of the medium or the addition of the reduced product of the oxidant had no significant effect on the rates of reactions. Decrease in dielectric constant of the medium by changing the solvent composition with methanol decreased the rate in all the cases. Two-pathway mechanisms have been considered to account for the observed kinetic and other effects. The rate controlling steps have been identified and co-efficients of these steps are calculated at different temperatures by varying [AA] at each temperature. The latter constants have been used to calculate the activation parameters associated with the rate-limiting steps. The rate constants are also predicted from the rate laws as [AA], [RuIII] and [H+] are varied. The predicted values are in good agreement with the experimental constants, thus providing support to the suggested mechanisms.