|Title||Iron(II) Catalysis in Oxidation of Hydrocarbons with Ozone in Acetonitrile|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||Bataineh, H, Pestovsky, O, Bakac, A|
|Type of Article||Article|
|Keywords||acid, alcohol, alkaline aqueous-solutions, atom transfer, catalysis, hydrogen-peroxide, hydroxyl radicals, ion, iron, kinetics, mechanism, o-center-dot, oxidation, ozone, reactivity, superoxide|
95%), whereas the uncatalyzed reaction generates a 1:1 mixture of benzaldehyde and benzoic acid. Similarly, aliphatic alcohols are oxidized to aldehydes/ketones, cyclobutanol to cyclobutanone, and diethyl ether to a 1:1 mixture of ethanol and acetaldehyde. The kinetics of oxidation of alcohols and diethyl ether are first-order in [Fe(CH3CN)(6)(2+)] and [O-3] and independent of [substrate] at concentrations greater than similar to 5 mM. In this regime, the rate constant for all of the alcohols is approximately the same, k(cat) = (8 +/- 1) x 104 M-1 s(-1), and that for (C2H5)(2)O is (5 +/- 0.5) x 104 M-1 s(-1). In the absence of substrate, Fe(CH3CN)(6)(2+) reacts with O-3 with k(Fe) = (9.3 +/- 0.3) x 104 M-1 s(-1). The similarity between the rate constants k(Fe) and k(cat) strongly argues for Fe(CH3CN)(6) (2+)/O-3 reaction as rate-determining in catalytic oxidation. The active oxidant produced in Fe(CH3CN)(6) (2+)/O-3 reaction is suggested to be an Fe(IV) species in analogy with a related intermediate in aqueous solutions. This assignment is supported by the similarity in kinetic isotope effects and relative reactivities of the two species toward substrates.
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