Solvent Effects Of The Oxidation Of Iron (II) - Tartrate Complex By Molecular Oxygen In Aqueous Solutions Of Alcohols

Abstract

The solvent effects on the oxidation of Fe(II)-tartrate by molecular oxygen have been investigated in aqueous acidic solutions of alcohols such as methanol, ethanol, isopropanol and t-butanol. The second-order rate constant of the oxidation increases with the addition of alcohols to the aqueous solutions. The rate constant values at 27.5+ 0.1°C are 0.245 M-' sec-' in the absence of alcohols, 0.266, 0.280, 0.344 and 0.393 M-' sec-i in the presence of 10% (V/V) methanol, ethanol, isopropanol and t-butanol, respectively. The rate constant also increases with the increase of the percentage of alcohols. Activation parameters for all systems are evaluated. The effect of solvent on the oxidation of Fe(II) is understood on the basis of replacement of water molecules coordinated to Fe(II) by the alcohol molecules and that the increase of the basicity of the alcohol increases the rate of oxidation of Fe(II).