| Autor: |
Rangappa, K., Anitha, N., Made Gowda, N. |
| Předmět: |
|
| Zdroj: |
Synthesis & Reactivity in Inorganic & Metal-Organic Chemistry; Sep2001, Vol. 31 Issue 8, p1499, 20p |
| Abstrakt: |
The kinetics of the Ru(III) catalysed oxidation of six derivatives of phenethyl alcohol (X-C6H4-CH2CH2OH where XH, Cl, Br, CH3, OCH3 or NO2) by manganese(III) sulfate, in sulfuric acid solution at 30°C, were followed spectrophotometrically at λmax =500 nm. The rate shows a first-order dependence on [Mn(III)] and Michaelis-Menten kinetics was observed with the substrate. The rate was of fractional-order in [Ru(III)]. Hammett acidity function (H0) has been invoked to explain the retardation of the rate by acid. Bunnett plots indicated the absence of water molecule participation in the rate-limiting step. Variation of the ionic strength and the dielectric constant and the addition of the reaction product Mn(II) and anions such as C1-, SO2+4, and F- have no effect on the rate. The solvent isotope effect k(H2O)/k(D2O) =1.38 was observed. Proton inventory studies were made in H2O-D2O mixtures. A linear free energy relationship was observed when the results were analyzed by Hammett and Okamoto-Brown equations. Activation parameters were computed. A mechanism consistent with the observed kinetics has been proposed. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
