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Titolo:
The effect of crystallite size on the activity and selectivity of the reaction of ethanol and 2-propanol over SAPO-34
Autore:
Dahl, IM; Wendelbo, R; Andersen, A; Akporiaye, D; Mostad, H; Fuglerud, T;
Indirizzi:
SINTEF Appl Chem, N-0314 Oslo, Norway SINTEF Appl Chem Oslo Norway N-0314 INTEF Appl Chem, N-0314 Oslo, Norway Norsk Hydro AS, N-3901 Porsgrunn, Norway Norsk Hydro AS Porsgrunn NorwayN-3901 ydro AS, N-3901 Porsgrunn, Norway
Titolo Testata:
MICROPOROUS AND MESOPOROUS MATERIALS
fascicolo: 1-2, volume: 29, anno: 1999,
pagine: 159 - 171
SICI:
1387-1811(199906)29:1-2<159:TEOCSO>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
SILICOALUMINOPHOSPHATE MOLECULAR-SIEVES; LIGHT OLEFINS; METHANOL; CONVERSION; CATALYST; HYDROCARBONS; PERFORMANCE; CO;
Keywords:
CHA; crystal size; MTO; SAPO;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
19
Recensione:
Indirizzi per estratti:
Indirizzo: Dahl, IM SINTEF Appl Chem, POB 124,Blindern, N-0314 Oslo, Norway SINTEF Appl Chem POB 124,Blindern Oslo Norway N-0314 slo, Norway
Citazione:
I.M. Dahl et al., "The effect of crystallite size on the activity and selectivity of the reaction of ethanol and 2-propanol over SAPO-34", MICROP M M, 29(1-2), 1999, pp. 159-171

Abstract

SAPO-34 was prepared according to a standardised recipe and separated intodifferent crystal size fractions by sedimentation in water. Three fractions with mean crystal diameters of about 0.25, 0.5 and 2.5 mu m were obtained, and are referred to as the fine, medium and coarse fractions, respectively. The fractions were analysed for their chemical composition (microprobe),crystallinity and phase purity (XRD), crystal size and shape (SEM and TEM), micropore volume and total surface area (BET N-2 adsorption), Si distribution and content (Si-29 NMR), acidity (NH3 TPD), and adsorption properties for propane. Ethanol and 2-propanol were reacted over the different size fractions at 400 degrees C. Both alcohols very rapidly dehydrated to ethene and propene, respectively, and the consecutive reactions of these olefins under MTO-like conditions were investigated. Propene reacted primarily to ethene and linear butanes, These reactions were found to be diffusion-limited at particle sizes >2 mu m and to have an effectiveness factor close to 1 for particle sizes <0.2 mu m. The deactivation of the catalyst proceeded in amanner consistent with further diffusional barriers being created rather than just the loss of active sites. Ethene was virtually non-reactive over virgin SAPO-34. After activation of the catalyst with a propene pulse, however, ethene conversion was achieved. This indicates that ethene alone is notable to form stable and reactive carbocation intermediates, but that it reacts with such ions once they have been formed. The reactions of ethene were found not to be diffusion-limited at particle sizes <25 mu m. (C) 1999 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 15/07/20 alle ore 04:54:28