“Complex” versus “free radical” mechanism for the catalytic decomposition of H2O2 by ferric ions

✍ Scribed by Mordechai L. Kremer

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 771 KB
• Volume: 17
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550171207

✦ Synopsis

Kinetic and spectrophotometric measurements made during the Fe3+ ion catalyzed decomposition of H,O, have been analyzed using the computer simulation method.

Improved values of the rate constants of the "complex scheme" and of the molar absorptivities of the intermediates were obtained: k,/Kw = 4.94 M-' min-',

The simulation revealed details of the reaction which were unavailable by other means and which explained several features of its kinetics. The total amount of 0, evolved in the reaction using [H,O,Ilo-' M has been calculated and found to be nearly stoichiometric. 0, evolution experiments in this region cannot, thus, distinguish between the "complex mechanism" predicting nearly stoichiometric evolution of 0, and the "free radical mechanism" predicting exactly stoichiometric amounts of 0'. There are discrepancies within the "free radical scheme" with regard to the correct values of the rate constants to fit the reactions of H,O, both with Fez' and Fe3' ions, as well as other reactions assumed to proceed via free radicals. *Walling used different numbering of the reactions of mechanism (A). Here the original numbering of Barb et al. is retained. 47, 462 (19511.