Copper (II) catalysis for oxidation of L-tryptophan by hexacyanoferrate(III) in alkaline medium : a kinetic and mechanistic approach
Joint Authors
Fawzi, Ahmad
Altas, Hatim M.
Asghar, Basim H.
Source
Journal of Saudi Chemical Society
Issue
Vol. 21, Issue 8 (31 Dec. 2017), pp.887-898, 12 p.
Publisher
Publication Date
2017-12-31
Country of Publication
Saudi Arabia
No. of Pages
12
Main Subjects
Abstract EN
The catalytic effect of copper(II) catalyst on the oxidation of L-tryptophan (Trp) by hexacyanoferrate( III) (HCF), has been investigated spectrophotometrically in an aqueous alkaline medium at a constant ionic strength of 0.5 mol dm 3 and at 25 C.
The stoichiometry for both the uncatalyzed and catalyzed reactions was 1:2 (Trp:HCF).
The reactions exhibited first order kinetics with respect to [HCF] and less than unit orders with respect to [Trp] and [OH ].
The catalyzed reaction exhibited fractional-first order kinetics with respect to [CuII].
The reaction rates were found to increase as the ionic strength and dielectric constant of the reaction medium increase.
The effect of temperature on the rates of reactions has also been studied, and the activation parameters associated with the rate-determining steps of the reactions have been evaluated and discussed.
Addition of the reaction product HCF(II) to the reaction mixture did not affect the rates.
Plausible mechanistic schemes for uncatalyzed and catalyzed reactions explaining all of the observed kinetic results have been proposed.
In both cases, the final oxidation products are identified as indole-3- acetaldehyde, ammonia, and carbon dioxide.
The rate laws associated with the reactions’ mechanisms are derived.
The rate constants of the slow steps of the reactions along with the equilibrium constants are also calculated.
American Psychological Association (APA)
Asghar, Basim H.& Altas, Hatim M.& Fawzi, Ahmad. 2017. Copper (II) catalysis for oxidation of L-tryptophan by hexacyanoferrate(III) in alkaline medium : a kinetic and mechanistic approach. Journal of Saudi Chemical Society،Vol. 21, no. 8, pp.887-898.
https://search.emarefa.net/detail/BIM-781230
Modern Language Association (MLA)
Asghar, Basim H.…[et al.]. Copper (II) catalysis for oxidation of L-tryptophan by hexacyanoferrate(III) in alkaline medium : a kinetic and mechanistic approach. Journal of Saudi Chemical Society Vol. 21, no. 8 (Dec. 2017), pp.887-898.
https://search.emarefa.net/detail/BIM-781230
American Medical Association (AMA)
Asghar, Basim H.& Altas, Hatim M.& Fawzi, Ahmad. Copper (II) catalysis for oxidation of L-tryptophan by hexacyanoferrate(III) in alkaline medium : a kinetic and mechanistic approach. Journal of Saudi Chemical Society. 2017. Vol. 21, no. 8, pp.887-898.
https://search.emarefa.net/detail/BIM-781230
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references : p. 897-898
Record ID
BIM-781230