Large Zeolite H-ZSM-5 Crystals as Models for the Methanol-to-Hydrocarbons Process: Bridging the Gap between Single-Particle Examination and Bulk Catalyst Analysis

Autor:	Hofmann, J.P., Mores, D., Aramburo, L.R., Teketel, S., Rohnke, M., Janek, J., Olsbye, U., Weckhuysen, B.M., Inorganic Chemistry and Catalysis, Sub Inorganic Chemistry and Catalysis
Přispěvatelé:	Sub Inorganic Chemistry and Catalysis, Faculteit Betawetenschappen
Jazyk:	angličtina
Rok vydání:	2013
Předmět:	chemistry.chemical_classification Heterogeneous catalysis Tof-sims Chemistry Organic Chemistry Analytical chemistry Methanol-to-hydrocarbons General Chemistry Coke Catalysis chemistry.chemical_compound Hydrocarbon Chemical engineering Zeolites Methanol ZSM-5 Zeolite Inert gas Microspectroscopy
Zdroj:	Chemistry-A European Journal, 19(26), 8533. Wiley
ISSN:	1521-3765
DOI:	10.1002/chem.201203351
Popis:	The catalytic, deactivation, and regeneration characteristics of large coffin-shaped H-ZSM-5 crystals were investigated during the methanolto- hydrocarbons (MTH) reaction at 350 and 500 8C. Online gas-phase effluent analysis and examination of retained material thereof were used to explore the bulk properties of large coffin-shaped zeolite H-ZSM-5 crystals in a fixed-bed reactor to introduce them as model catalysts for the MTH reaction. These findings were related to observations made at the individual particle level by using polarization-dependent UV-visible microspectroscopy and mass spectrometric techniques after reaction in an in situ microspectroscopy reaction cell. Excellent agreement between the spectroscopic mea- ACHTUNGTRENUNGsurements and the analysis of hydrocarbon deposits by means of retained hydrocarbon analysis and time-of-flight secondary-ion mass spectrometry of spent catalyst materials was observed. The obtained data reveal a shift towards more condensed coke deposits on the outer zeolite surface at higher reaction temperatures. Zeolites in the fixed-bed reactor setup underwent more coke deposition than those reacted in the in situ microspectroscopy reaction cell. Regeneration studies of the large zeolite crystals were performed by oxidation in O2/inert gas mixtures at 550 8C. UV-visible microspectroscopic measurements using the oligomerization of styrene derivatives as probe reaction indicated that the fraction of strong acid sites decreased during regeneration. This change was accompanied by a slight decrease in the initial conversion obtained after regeneration. H-ZSM-5 deactivated more rapidly at higher reaction temperature.
Databáze:	OpenAIRE
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