Duality on the oxidation of (phenylthio)acetic acids by vanadium (V) and iron (III)
The kinetics of oxidation of (phenylthio)acetic acid and few para-substituted (phenylthio)acetic acids by vanadium(V) and iron(III) have been studied in acid medium. In both the cases , the order in substrate and oxidant is one each. Both the reactions are catalysed by hydrogen ions and follow a free radical path. A high negative ρ value (-3.64) is obtained in the case of vanadium(V) oxidation and the product is the corresponding diphenyldisulphide. The ρ value obtained in the iron(III) oxidation is -1.22 and the identified product is its sulphoxide. On the basis of the kinetic results suitable mechanisms have been proposed and discussed.
Karunakaran,Gurumurthy,Elango
p. 984 - 986
(2007/10/03)
Kinetics of Oxidation of Thallium(I) by Hexacyanoferrate(III) in Acid Medium in Presence of Chloride Ions
The kinetics of title reaction in the presence of chloride is studied as a function of acid concentration and the rate is found to be proportional to the Hammett acidity function, - H0.The orders with respect to hexacyanoferrate(III), total thallium and hydrogen ion are all unity.Neutral salts exert no influence on the reaction rate but a decrease in the dielectric constant of the medium is found to cause an increase in the rate.A probable mechanism to explain the observed kinetics is proposed and it involves chloride complexes of thallium(I) in the rate-determining step.
Sriramam, K.,Sarma, B. S. R.,Kalidas, K.,Ravindranath, P.,Rao, R. Panduranga