Catalytic oxidation of 2-mercaptoethanol by cobalt(II)-phthalocyanine complexes intercalated in layered double hydroxides Original Research Article

Complexes of cobalt(II)-2,9,16,23-phthalocyanine tetracar☐ylic acid and cobalt(II)-2,9,16,23-phthalocyanine tetrasulfonic acid were intercalated into the interlayer space of hydrotalcite by anion exchange. Intercalation compounds of various concentrations of the cobalt phthalocyanine complexes were prepared in this way. The distribution of the complexes in hydrotalcite was studied by means of electron spin resonance spectroscopy. The intercalation compounds were used as catalysts for 2-mercaptoethanol oxidation in aqueous solution. The catalyst effectiveness decreased upon increasing the concentration of the intercalated cobalt phthalocyanine complexes. Aggregation and crystallization of the phthalocyanine molecules on the hydrotalcite surface and formation of low active μ-peroxo complexes between closely ion-exchanged complexes resulted in a decrease in the turnover frequency of the oxidation.