Oxidation of catecholamines on chitosan-immobilized Co(II) salen complexes

L-Adrenaline and 3,4-dihydroxyphenylalanine (dopa) oxidation by molecular oxygen in the presence of the Co(II) complex of bis(salicylideneethylene diamine) (CoSalen) immobilized on unmodified chitosan and chitosan modified by 4-pyridinecarboxaldehyde is studied in aqueous solutions under mild conditions. The catalysts prepared are selective with respect to oxidation of the chosen substrates. Preparation of binary composite egg-shell systems, with a thin film of low-loaded CoSalen-chitosan supported on macroporous SiO₂ makes it possible to increase sufficiently the specific surface area and the efficiency of the catalyst.