Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
Methane partial oxidation in iron zeolites: theory versus experiment
Autore:
Knops-Gerrits, PP; Goddard, WA;
Indirizzi:
Univ Catholique Louvain, Dept Chim, Lab Inorgan Chem & Organ Mat, CMAT, B-1348 Louvain, Belgium Univ Catholique Louvain Louvain Belgium B-1348 , B-1348 Louvain, Belgium CALTECH, Beckman Inst 139 74, Mat & Proc Simulat Ctr, Pasadena, CA 91125 USA CALTECH Pasadena CA USA 91125 & Proc Simulat Ctr, Pasadena, CA 91125 USA
Titolo Testata:
JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
fascicolo: 1, volume: 166, anno: 2001,
pagine: 135 - 145
SICI:
1381-1169(20010122)166:1<135:MPOIIZ>2.0.ZU;2-E
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-DYNAMICS SIMULATIONS; N2O DECOMPOSITION; NITROUS-OXIDE; BIOMIMETIC OXIDATION; SELECTIVE OXIDATION; FEZSM-5 ZEOLITE; COMPLEXES; BENZENE; HYDROXYLATION; MONOOXYGENASE;
Keywords:
iron zeolites; methane conversion; zeolite synthesis; metal nuclearity; ab initio calculation; force field; physico-chemical characterisation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
34
Recensione:
Indirizzi per estratti:
Indirizzo: Knops-Gerrits, PP Univ Catholique Louvain, Dept Chim, Lab Inorgan Chem & Organ Mat, CMAT, Batiment Lavoisier,Pl L Pasteur 1, B-1348 Louvain, Belgium Univ Catholique Louvain Batiment Lavoisier,Pl L Pasteur 1 Louvain Belgium B-1348
Citazione:
P.P. Knops-Gerrits e W.A. Goddard, "Methane partial oxidation in iron zeolites: theory versus experiment", J MOL CAT A, 166(1), 2001, pp. 135-145

Abstract

The conversion of methane to methanol over zeolitic cr-oxygen sites has been demonstrated using Fe-ZSM-5. To discriminate between mono- and poly-nuclear active sites, we prepared the [Fe]-ZEO with iron in the ZEOlite latticevia direct synthesis and Fe, -ZEO, by dispersion of x wt.% iron on the ZEOlite. Shape-selective formation of nano-clusters of iron oxides with various sizes is realized inside the pore-sizes varying from 10.0 to 8.0 and 6.3 to 4.3 Angstrom of the CFI, MOR, MFI, and CHA zeolites. The Fe-K edge X-rayabsorption data were obtained for the Fe-CIT-5, Fe-ZSM-5, Fe-MOR and Fe-CHA zeolites containing iron clusters. In Mossbauer spectroscopy the absence and presence of a hyperfine magnetic field (HMF) for [Fe]-CIT-5 and Fe-CIT-5 are seen. The quantum mechanics calculations analyze the different environments of iron, e,g, the tetrahedral lattice occluded species, the di-nuclear sites attached to the zeolite, the nano-phase hematite sites. The molecular mechanics calculations involve a new molecular mechanics force field, the universal force field (UFF). alpha -Oxygen can be formed on di-nuclear iron rites in zeolites by N2O decomposition at elevated temperatures and is dependent on the zeolite structure utilized. Fe-chabazite (CHA), Fe-mordenite (MOR) and Fe-CIT-5 (CFI) were found to be less active than Fe-ZSM-5. A range of preparative and activation conditions were studied preceding methane conversion. Proper activation is essential to maximize catalyst actvity, e.g. pretreatment under vacuum at 800-900 degreesC, activation with N2O at 250 degreesC and reaction with methane at 20 degreesC, Extraction of methanol from the catalyst is performed with H2O Structure-activity effects are discussed. (C) 2001 Elsevier Science B.V, All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/07/20 alle ore 01:21:08