Abstract
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 0.5moldm−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.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.