title: Binder Effects in SiO2- and Al2O3-Bound Zeolite ZSM-5-Based Extrudates as Studied by Microspectroscopy.
abstract: Microspectroscopic methods were explored to investigate binder effects occurring in ZSM-5-containing SiO2- and Al2O3-bound millimetre-sized extrudates. Using thiophene as a selective probe for Brønsted acidity, coupled with time-resolved in situ UV/Vis and confocal fluorescence microspectroscopy, variations in reactivity and selectivity between the two distinct binder types were established. It was found that aluminium migration occurs in ZSM-5-containing Al2O3-bound extrudates, forming additional Brønsted acid sites. These sites strongly influence the oligomer selectivity, favouring the formation of thiol-like species (i.e., ring-opened species) in contrast to higher oligomers, predominantly formed on SiO2-bound ZSM-5-containing extrudates. Not only were the location and distribution of these oligomers visualised by 3 D analysis, it was also observed that more conjugated species appeared to grow off the surface of the zeolite ZSM-5 crystals (containing less conjugated species) into the surrounding binder material. Furthermore, a higher binder content resulted in an increasing overall reactivity owing to the greater number of stored thiophene monomers available per Brønsted acid site.
authors.affiliation: Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht (The Netherlands).
authors.forename: Gareth T
authors.initials: GT
authors.lastname: Whiting
authors.affiliation: Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht (The Netherlands).
authors.forename: Florian
authors.initials: F
authors.lastname: Meirer
authors.affiliation: ExxonMobil Process Technology, ExxonMobil Research and Engineering Company, 1545 Route 22 East, Annandale, NJ 08801 (USA).
authors.forename: Machteld M
authors.initials: MM
authors.lastname: Mertens
authors.affiliation: ExxonMobil Chemical Europe, Inc. European Technology Centre, Hermeslaan 2, B-1831, Machelen (Belgium).
authors.forename: Anton-Jan
authors.initials: AJ
authors.lastname: Bons
authors.affiliation: Corporate Strategic Research, ExxonMobil Research and Engineering Company, 1545 Route 22 East Annandale, NJ 08801 (USA).
authors.forename: Brian M
authors.initials: BM
authors.lastname: Weiss
authors.affiliation: Corporate Strategic Research, ExxonMobil Research and Engineering Company, 1545 Route 22 East Annandale, NJ 08801 (USA).
authors.forename: Paul A
authors.initials: PA
authors.lastname: Stevens
authors.affiliation: ExxonMobil Chemical Europe, Inc. European Technology Centre, Hermeslaan 2, B-1831, Machelen (Belgium).
authors.forename: Emiel
authors.initials: E
authors.lastname: de Smit
authors.affiliation: Inorganic Chemistry and Catalysis Group, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG, Utrecht (The Netherlands).
authors.forename: Bert M
authors.initials: BM
authors.lastname: Weckhuysen
keywords: acidity; fluorescence spectroscopy; microporous materials; sulfur heterocycles; zeolites