The work discussed the role of cobalt and manganese complexes in the liquid-phase catalytic benzylic oxidation in polar and apolar media. Evidence that hydrocarbon is involved during oxidation with the transition metal ion is presented. It is supposed that reaction acceleration caused by bromide salts is due to the increase in the rate of the electron transfer and no initiation by bromine atoms exist. The reasons for different product selectivity in the presence of cobalt and manganese are explained and the synergistic effects of mixed catalysts are discussed. Thus cobalt is active in the oxidation of hydrocarbons and alcohols, while manganese is active in oxidation of carbonyl compounds. These assumptions allowed to build a system of differential rate equations.

A practical model was developed for liquid-phase Mn 3+catalysed oxidation of ethyl benzene by O 2 . The model describes time profiles of concentrations of ethyl benzene and two intermediate oxidation products (methyl phenyl carbinol and acetophenone). The kinetic model of acetophenone oxidation to benzoic acid was also obtained. The influence of the main products of the ethyl benzene oxidation on the reaction kinetics is discussed. It was established that the addition of ethyl benzene hydroperoxide does not affect the reaction rate; the addition of methyl phenyl carbinol inhibits the reaction. The addition of acetophenone promotes the reaction and neutralises the inhibiting effect of methyl phenyl carbinol. The proposed reaction mechanism includes free-radical ethyl benzene oxidation. The process is initiated by the acetophenone interaction with Mn 3+ ion, and the chain is propagated due to the hydroperoxide interaction with ethyl benzene. The chain termination is quadratic. The length of the oxidation chain was calculated. The inhibition is caused by the manganese bonding to form an inactive complex. The obtained system of differential rate equations adequately describes the process.

The liquid-phase oxidation of ethyl benzene by O2 catalysed by manganese stearate (MnSt2) in a stirred batch reactor has been studied. The main reaction products are ethyl benzene hydroperoxide, methyl phenyl carbinole, and acetophenone. It was established that the reaction includes four basic macro-stages:  an induction period, a period of accelerated ethyl benzene consumption, a period of slowing-down, and an inhibition step. It was shown that the initial rate of the second step is described by the equation r 0 = k[EB]0 . The observed experimental data allowed the supposition that the reaction proceeds by the radical-chain mechanism with participation of hydroperoxide radicals. The overall process is possibly initiated by Mn3+ ions.

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