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SM ISO690:2012 MANUCHAROVA, Lorietta, BAKHTCHADJIAN, Robert, TAVADYAN, Levon. Anchored dioxo-mo-complex as photocatalyst in oxidation of halogen derivatives of aromatic hydrocarbons. In: Ecological and environmental chemistry : - 2017, Ed. 6, 2-3 martie 2017, Chișinău. Chisinau, Republic of Moldova: Academy of Sciences of Moldova, 2017, Ediția 6, p. 134. |
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Ecological and environmental chemistry Ediția 6, 2017 |
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Conferința "Ecological and environmental chemistry 2017" 6, Chișinău, Moldova, 2-3 martie 2017 | ||||||
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Pag. 134-134 | ||||||
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Wide use of chlorinated derivatives of mono and polycyclic hydrocarbons in different areas, including chemical industry, causes serious ecological and environmental problems. Selective oxidation and oxidative destruction of them are suitable ways for their neutralization. In our work a new selective catalyst by the application of transition metal dioxo-complex, anchored on photosensitive material, were proposed in these aims. Particularly, it has been investigated catalytic properties of the fully characterized dioxo-Mo(VI)-dichloro[4,4′-dicarboxylato-2,2′-bipyridine] complex, anchored on the TiO2 in oxidation and oxidative destruction of cloroehylbezene, dichlorodiphenylmethane, dichlorodiphenyltrichloroethane (DDT) with dioxygen under UV-irradiation, in a suspension of acetonitrile, in “mild” reaction conditions. Catalytic action of heterogeneous dioxo-Mo-complexes is based on the redox properties of Mo-active centers (MoVI ⇆ MoIV). The oxidative and reductive stages of reaction, composing a catalytic cycle, were separated temporally in experimental conditions. It was shown that the main primary reaction in the first stage is selective oxo-atom transfer from Mo-complex to the benzylic carbon of hydrocarbon by the formation of corresponding alcohols under UV irradiation, while the re-oxidation of catalyst (MoIV →MoVI) by dioxygen may occur in the dark. Particularly, the catalyst exhibits exceptional activity in selective oxidation of DDT to dicofol, in our knowledge, practically unavailable by direct oxidation with oxygen in other pathways. For instance, 35% of DDT may be transformed to dicofol by the 21% yield in several catalytic cycles. The probable mechanism of the selective oxidation and further oxidative destruction of the chlorinated derivatives of mentioned hydrocarbons under reaction conditions has been discussed. It has been hypothesized that the acceleration of reaction in second and further catalytic cycles may take place by the formation of oxo-peroxo-Mo(VI) moieties in the first stage of the catalytic cycle. |
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