MECHANISM OF INITIATION AND INHIBITION BY MN(II) IN HYDROCARBON OXIDATION IN THE PRESENCE A COBALT-MANGANESE BROMIDE CATALYST

The synergism of cobalt and magnesium salts in the oxidation of alkyla romatic hydrocarbons in the presence of a metal bromide catalyst in a solution of acetic acid was studied. For this purpose, the rate of O-2 consumption was measured simultaneously with the intensity of chemilu minescence, which accompanies the oxidation process. Mn(II) was found to initiate and inhibit the process. The function of Mn(II) as an init iator is associated with the formation of hydroperoxide ROOH by the re action of RO2. radicals with Mn2+ ions. The function of Mn(II) as an i nhibitor is associated with the formation of a carbonyl product. The r eactions of RO2. with Mn2+ occur via the formation of an intermediate complex RO2-Mn3+ with partial charge transfer. Free Mn2+ ions efficien tly deactivate the RO2-Mn3+ complex. Their stimulating effect on elect ron transfer in this complex results in the formation of a carbonyl pr oduct. Free Mn2+ ions also efficiently deactivate the RO2-Co3+ complex , which is an intermediate product in the reactions of RO2. with Co2ions. A number of kinetic parameters of the initiation and inhibition steps were estimated.