On the Nature of Active Sites in Benzene Oxidation to Phenol with N2O over H-ZSM-5 with Low Fe Concentrations

0181427 - UFCH-W 20020093 RIV US eng J - Journal Article
Kubánek, Petr - Wichterlová, Blanka - Sobalík, Zdeněk
On the Nature of Active Sites in Benzene Oxidation to Phenol with N2O over H-ZSM-5 with Low Fe Concentrations.
Journal of Catalysis. Roč. 211, č. 1 (2002), s. 109-118. ISSN 0021-9517. E-ISSN 1090-2694
R&D Projects: GA AV ČR IAA4040007
Institutional research plan: CEZ:AV0Z4040901
Keywords : H-ZSM-5 * Fe-zeolites * N2O oxidation of benzene
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 3.118, year: 2002

Selective oxidation of benzene with N2O to phenol was investigated at 350 and 450 .DEG.C on H-ZSM-5 zeolites with different Si/Al composition, concentrations of iron ranging from 30 to 2000 ppm, and with gallium (2000 ppm). Zeolites dehydrated at 480 .DEG.C, dehydroxylated at 720 .DEG.C and steamed in the temperature range from 500 to 780 .DEG.C as well as those exchanged by NaCl and treated in NaOH solution were used. IR spectra of OH groups and of adsorbed d3-acetonitrile on zeolites were employed to determine concentration of Broensted and Al-Lewis sites. ESR spectra of Fe(III) ions and IR spectra of perturbed framework T-O-T bonds due to the presence of Fe(II) ions in cationic sites of the reduced zeolites were applied to characterize location of Fe ions in zeolites. It has been shown that the rate of phenol formation correlates with the concentration of Fe in the zeolite, but is not affected by the presence of gallium.
Permanent Link: http://hdl.handle.net/11104/0077999