MECHANISM OF CATALYTIC-OXIDATION OF SO2 BY OXYGEN IN THE PRESENCE OF CO(II) AND MN(III) PORPHYRINS

The formation of preliminarily reduced complexes between oxygen and metalloporphyrins (M(n+p)) has been detected by impulse radiolysis and electrochemical and spectroscopic procedures. Transfer processes of electrons inside these complexes accompanied by the formation of oxy-complexes M(n-l)+p... O2, super-oxy-complexes M(n+p)...O2-/., and peroxy-complexes M(n+1)+P...O2(2-) have been studied. The reaction capacity of the recorded complex in relation to the substrate (SO2) was studied. It has been shown that the substrate is oxidized according to two concurrent mechanisms: interaction with the peroxy-complex and a chain mechanism. It has been established that catalytic processes can occur in the system. The functions of the catalyst (Mn+p) include the specialized reduction of molecular oxygen to a peroxide ion O2(2-) and the regeneration of the active forms of the substrate, which are able to initiate autocatalytic processes.