Raskola L. Reactions of ozone decomposition by porous carrier supported complexes of Co(II), Cu(II), and Mn(II)

Subject of Study: ozone in the reactions of its low-temperature decomposition by porous carrier supported complexes of Co(II), Cu(II), and Mn(II). Objective of Study: The objective of study is the ascertainment of relationship between the composition of oxide carrier supported complexes of Co(II), Cu(II), and Mn(II) and their reactivity in the low-temperature ozone decomposition. Research Methods: kinetic, adsorption, and spectral (EPR and ESDR). Theoretical and Practical Results and Novelty: It is possible to use the ozone decomposition regularities revealed and the methods developed for the prediction of effects of a Men+ nature, of thermodynamic activities of ligands and water, and of a carrier nature on the composition and reactivity of complexes of Co(II), Cu(II), and Mn(II) choosing efficient supported metal-complex catalysts for redox reaction where ozone is a reactant. The values of both successive stability constants and partial kinetic constants obtained for immobilized and impregnated MeXj2-j/SiO2 complexes can be used as reference ones. The distribution diagrams calculated for SiO2-supported chloride complexes of Co(II), Cu(II), and Mn(II) can be used for the identification of composition for complexes of the metals supported on other oxide carriers. A catalyst of MnCl2/AC composition has been developed for the equipment of both light-weight cartridge respirators and apparatuses for sanitary air cleaning. First, some analogies in properties of silica-supported and dissolved metal complexes as to the ozone decomposition reaction as well as some correlations between stability and reactivity of the impregnated MeClj2-j/SiO2 complexes have been ascertained. As is shown, MeXj2-j/SiO2 complexes prepared by both adsorption and impregnation methods can be the catalysts for the low-temperature ozone decomposition at the defined [Me2+]/[O3] and [Me2+]/[X-] ratios. In case of the impregnated MeXj2-j/SiO2 complexes, the reaction stoichiometry becomes different with an increase in the [Me2+]/[O3] ratio. Mechanisms of ozone decomposition by the immobilized and impregnated MeXj2-j/SiO2 complexes have been suggested. They contain the following stages: the intraspheric Me(II) oxidation by ozone, the chain-radical reaction with participation of OH radicals, and the reduction of oxidized forms of the complexes. Kinetic equations describing initial stages of the Me(II) oxidation by ozone have been proposed. As is shown, activated charcoals generate OH radicals in process of their interaction with ozone and, thereby, improve catalytic properties of MeCl2/AC complexes. The catalytic activity of the latter increases in the order: CoCl2<CuCl2<MnCl2. Degree of inculcation: The data obtained in the work are applied to the educational process in Department of Inorganic Chemistry and Chemical Ecology. They are used in special course "Ecological Catalysis" in its topic "Physicochemical Principles of Air Purification to Remove Ozone". Scope of Application: Inorganic chemistry.