Liquid phase oxidation of mesitylene to 3,5-dimethylbenzaldehyde

Liquid phase oxidation of mesitylene to 3,5-dimethylbenzaldehyde has been studied in the presence of cobalt bromide catalysts activated with triethanolamine or pyridine. The selectivity for the aldehyde is affected by the presence of the amine, by solvent, and only little by concentration of the catalyst and its components. The lower value of rate constant of the subsequent oxidation of the aldehyde, k2 = (7.66 ± 0.39) . 10-5 s-1, as compared with that of the oxidation of mesitylene, k1 = (1.66 ± 0.13) . 10-4 s-1 at 60 °C, indicates an important role of the cooxidation reactions in the process of oxidation of mesitylene, which affects the reaction selectivity.