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Titolo:
NO reduction over La2O3 using methanol
Autore:
Toops, TJ; Walters, AB; Vannice, MA;
Indirizzi:
Penn State Univ, Dept Chem Engn, Fenske Lab 107, University Pk, PA 16802 USA Penn State Univ University Pk PA USA 16802 7, University Pk, PA 16802 USA Adv Energy Res, Austin, TX 78727 USA Adv Energy Res Austin TX USA 78727Adv Energy Res, Austin, TX 78727 USA
Titolo Testata:
CATALYSIS LETTERS
fascicolo: 2-4, volume: 64, anno: 2000,
pagine: 65 - 75
SICI:
1011-372X(2000)64:2-4<65:NROLUM>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
SELECTIVE CATALYTIC REDUCTION; NITRIC-OXIDE; FORMALDEHYDE OXIDATION; NITROGEN MONOXIDE; DECOMPOSITION; ALUMINA; CH4; EMISSIONS; KINETICS; SR/LA2O3;
Keywords:
NO reduction; CH3OH; La2O3; methyl nitrite; kinetics;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Engineering, Computing & Technology
Citazioni:
35
Recensione:
Indirizzi per estratti:
Indirizzo: Vannice, MA Penn State Univ, Dept Chem Engn, Fenske Lab 107, University Pk, PA 16802 USA Penn State Univ University Pk PA USA 16802 y Pk, PA 16802 USA
Citazione:
T.J. Toops et al., "NO reduction over La2O3 using methanol", CATAL LETT, 64(2-4), 2000, pp. 65-75

Abstract

Nitric oxide (NO) reduction by methanol was studied over La2O3 in the presence and absence of oxygen. In the absence of O-2, CH3OH reduced NO to bothN2O and N-2, with selectivity to dinitrogen formation decreasing from around 85% at 623 K to 50-70% at 723 K. With 1% O-2 in the feed, rates were 4-8times higher, but the selectivity to N-2 dropped from 50% at 623 K to 10% at 723 K. The specific activities with La2O3 for this reaction were higher than those for other reductants; for example, at 773 K with hydrogen a specific activity of 35 mu mol NO/s m(2) was obtained whereas that for methanolwas 600 mu mol NO/s m(2). The Arrhenius plots were linear under differential reaction conditions, and the apparent activation energy was consistentlynear 14 kcal/mol with CH3OH. Linear partial pressure dependencies based ona power rate law were obtained and showed a near-zero order in CH3OH and anear-first order in H-2. In the absence of O-2, a Langmuir-Hinshelwood type model assuming a surface reaction between adsorbed CH3OH and adsorbed NO as the slow step satisfactorily fitted the data, and the model invoking twotypes of sites provided the best fit and gave thermodynamically consistentrate constants. In the presence of O-2 a homogeneous gas-phase reaction between O-2, NO, and CH3OH occurred to yield methyl nitrite. This reaction converted more than 30% of the methanol at 300 K and continued to occur up totemperatures where methanol was fully oxidized. Quantitative kinetic studies of the heterogeneous reaction with O-2 present were significantly complicated by this homogeneous reaction.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 08/08/20 alle ore 18:29:26