Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

With a view to assess the effect of acetates of the groups Ia and IIon the activity of cobalt bromide catalyst, oxidation of mesitylene and pseudo-cumene in a temperature range of 90 to °C has been investigated. At 100°C the acetate anions retarded the oxidation in the initial stage and increased selectivity of the oxidation of mesitylene to 3,5-dimethylbenzaldehyde, which intermediate was formed to a concentration of 42 mol%. The presence of acetates also affected distribution of isomers of aromatic dicarboxylic acids and the contents of aldehydo acids. The resultant effect of the simultaneous presence of acetate anions and nitrogen compounds on the activity of cobalt bromide catalysts depended on the nitrogen compound; with aminoacetic acid and hexamethylenediamine the oxidation rate and yields of aromatic acids were markedly increased. As conductance measurements indicated, the presence of acetates enhanced the formation of ionic forms of the complexes.