Oxidation of polyalkylated aromates. I. The influence of 3,5-dimethylbenzaldehyde on oxidation of mesitylene

I t has been shown that the oxidation of mesitylene to aromatic acids with oxygen in acetic acid at 90°C catalyzed by Co(II) and bromine salts is manifested on the absorption curves of oxygen by an inflection due to a rapid oxidation of 3,5-dimethylbenzaldehyde, the content of which in the mixture is approximately 26 mole %. Under these reaction conditions the oxidation of 3,5-dimethylbenzaldehyde is influenced mainly by the presence of mesitylene and organic bromides formed during the oxidation. In the initial stage of oxidation, 3,5-dimethylbenzaldehyde added to mesitylene does not markedly accelerate the reaction rate; when added after the rapid oxidation period associated with the inflection on the absorption curve, 3,5-dimethylbenzaldehyde accelerates the reaction several times.