The Oxidation of Substituted Toluenes by Cobalt(III) Acetate in Acetic Acid Solution

Abstract

The reaction products and kinetics of the oxidation of several substituted toluenes by Co111 acetate in acetic acid solution were determined. Under anaerobic conditions the substituted toluenes were first converted into benzyl acetate and subsequently into benzaldehyde. Under anaerobic and aerobic conditions the same rate equation and rate constant were found for the oxidation, but the product distribution differed strongly. The main products of the aerobic oxidation are benzaldehyde and benzoic acid, derived from the substituted toluenes used. Regeneration of Co111 acetate occurs in aerobic solutions, which leads to stationary values for the concentration ratios Coni/Co" and RCHO/RCH3. A reaction mechanism is proposed to explain the results obtained.

Conversion of Cobalt(II) Acetate into Cobalt(III) Acetate by Autoxidizing Benzaldehyde

“…The first-order rate constant has a value of 9 X 10-7 min-1 (25 °C). For autoxidations of benzaldehyde inhibited by phenols the same kinetics and the same rate constant were found (Hendriks et al, 1977). It follows therefore that Co11 acetate acts as an inhibitor for the autoxidation of benzaldehyde in the same manner as phenols.…”

“…Horizontally placed capillary tubes were filled with aerobic solutions of benzaldehyde and Co11 acetate in acetic acid (25 °C). In all cases the initial oxygen concentration (see Hendriks et al, 1977) was higher than the initial concentration of Co11 acetate to prevent a fast depletion of oxygen in the solution. At one end of the tubes a small amount of an acetic acid solution of perbenzoic acid was added, which resulted in the formation of green Com compounds in the boundary of the latter with the original solution.…”

A Kinetic Model for Toluene Oxidation Comprising Benzylperoxy Benzoate Ester as Reactive Intermediate in the Formation of Benzaldehyde

“…Perbenzoic acid can also be decomposed to benzoic acid by Co(II) through an overall reaction described by Hendriks et al (1978a), see Equation (11).…”

Kinetics of the Electrochemically Assisted Autoxidation of Toluene in Acetic Acid

“…However, the study of Hendriks et al, 9 which concerns the oxidation of 18 alkyl aromatics including toluene, deserves particular attention. The law proposed by these authors is characterized by an order of 2 with respect to the Co III concentration This law is associated with a complex reaction mechanism.…”