Homogeneous catalysis of n-propyl mercaptan oxidation with a cobalt tetraphenylporphyrin complex

A kinetic study of the oxidation of n -propyl mercaptan (PrSH) with chloridotetraphenylporphyrinatocobalt(III) in the absence of oxygen has been performed. The activation parameters of this reaction have been found to be close to those of the oxidation step of the Co(II) complex, and the structure of the transition state has been hypothesized. A stepwise mechanism of PrSH oxidation in the presence of Co complexes is proposed, comprising the sequential oxidation of PrSH with cobalt(III) tetraphenylporphyrinate and the oxidation of the resulting Co(II) complex with oxygen. The adequacy of the proposed scheme has been kinetically substantiated using the experimental data.