Document Detail


Staining of Fluid-Catalytic-Cracking Catalysts: Localising Brønsted Acidity within a Single Catalyst Particle.
MedLine Citation:
PMID:  22161809     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
A time-resolved in situ micro-spectroscopic approach has been used to investigate the Brønsted acidic properties of fluid-catalytic-cracking (FCC) catalysts at the single particle level by applying the acid-catalysed styrene oligomerisation probe reaction. The reactivity of individual FCC components (zeolite, clay, alumina and silica) was monitored by UV/Vis micro-spectroscopy and showed that only clay and zeolites (Y and ZSM-5) contain Brønsted acid sites that are strong enough to catalyse the conversion of 4-fluorostyrene into carbocationic species. By applying the same approach to complete FCC catalyst particles, it has been found that the fingerprint of the zeolitic UV/Vis spectra is clearly recognisable. This almost exclusive zeolitic activity is confirmed by the fact that hardly any reactivity is observed for FCC particles that contain no zeolite. Confocal fluorescence microscopy images of FCC catalyst particles reveal inhomogeneously distributed micron-sized zeolite domains with a highly fluorescent signal upon reaction. By examining laboratory deactivated FCC catalyst particles in a statistical approach, a clear trend of decreasing fluorescence intensity, and thus Brønsted acidity, of the zeolite domains is observed with increasing severity of the deactivation method. By comparing the average fluorescence intensities obtained with two styrenes that differ in reactivity, it has been found that the Brønsted acid site strength within FCC catalyst particles containing ZSM-5 is more uniform than within those containing zeolite Y, as confirmed with temperature-programmed desorption of ammonia.
Authors:
Inge L C Buurmans; Javier Ruiz-Martínez; Sanne L van Leeuwen; David van der Beek; Jaap A Bergwerff; William V Knowles; Eelco T C Vogt; Bert M Weckhuysen
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-12-9
Journal Detail:
Title:  Chemistry (Weinheim an der Bergstrasse, Germany)     Volume:  -     ISSN:  1521-3765     ISO Abbreviation:  -     Publication Date:  2011 Dec 
Date Detail:
Created Date:  2011-12-13     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9513783     Medline TA:  Chemistry     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Affiliation:
Inorganic Chemistry and Catalysis Group, Department of Chemistry, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht (The Netherlands), Fax: (+31) 30-251-1027.
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