Mechanism of catalytic decomposition of pentachlorophenol by a highly recyclable heterogeneous SiO(2)-[Fe-porphyrin] catalyst

 
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2010 (EN)
Mechanism of catalytic decomposition of pentachlorophenol by a highly recyclable heterogeneous SiO(2)-[Fe-porphyrin] catalyst (EN)

Christoforidis, K. C. (EN)

Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας (EL)
Christoforidis, K. C. (EN)

A novel heterogenized FeR(4)P-SiO(2) shows enhanced catalytic efficiency for PCP conversion vs. the homogeneous FeR(4)P catalyst. The heterogenized FeR(4)P-SiO(2) catalyst is highly recyclable in the presence of imidazole in solution. EPR and DR-UV-Vis data provide direct evidence that high-valent iron species [R(4)P(+center dot)Fe(IV)=O] are formed in the heterogenized FeR(4)P-SiO(2) system. The electron spin density of the al, cation radical (Por(+center dot)) is mainly localised on the tetrapyrole frame, and this results in the observed weak magnetic coupling between the S = 1 oxo-ferryl moiety (Fe(IV)=O) and the S = 1/2 porphyrin cation radical (Por(+center dot)). A catalytic cycle mechanism is suggested. Accordingly, the reduction in [R(4)P(+center dot)Fe(IV)=O] can proceed via a substrate molecule, in a one electron-transfer, thus producing [R(4)PFe(IV)] plus a radical entity derived from the substrate. Then, a second electron-transfer to [R(4)PFe(IV)] leads to the regeneration of the initial R(4)PFe(III) state. This second electron can originate from either a substrate molecule or a radical substrate species. (C) 2009 Elsevier Inc. All rights reserved. (EN)

heterogeneous catalyst (EN)

Πανεπιστήμιο Ιωαννίνων (EL)
University of Ioannina (EN)

Journal of Catalysis (EN)

English

2010

<Go to ISI>://000275966100019

Elsevier (EN)



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