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Si-MFI Crystallization Using a "Dimer" and "Trimer" of TPA Studied with Small-Angle X-ray Scattering

de Moor, Peter-Paul E. A. and Beelen, Theo P. M. and van Santen, Rutger A. and Beck, Larry W. and Davis, Mark E. (2000) Si-MFI Crystallization Using a "Dimer" and "Trimer" of TPA Studied with Small-Angle X-ray Scattering. Journal of Physical Chemistry B, 104 (32). pp. 7600-7611. ISSN 1520-6106. https://resolver.caltech.edu/CaltechAUTHORS:20170419-111654124

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Abstract

The formation and consumption of precursors and the crystallization of Si-MFI using bis(tripropylammonium) hexamethylene dihydroxide (“dimer” of tetrapropylammonium cation, TPA) and bis(tripropylammonium-N-N‘-hexamethylene)-N‘ ‘,N‘ ‘-dipropylammonium trihydroxide (“trimer” of TPA) as structure-directing agents have been investigated in situ using simultaneous, time-resolved, SAXS and WAXS and using USAXS. The formation of 2.8-nm-sized primary units is observed upon dissolution of the silica source, which is in agreement with results from earlier studies on systems with the TPA cation as a structure-directing agent. Aggregation of these nanometer-scale primary units to 10−15-nm-sized particles is found to be an essential step in nucleation of the zeolite. Crystal growth occurs via the addition of the primary units to the growing crystal. Although the size of the primary units for MFI is independent of the structure-directing agent used, the organic species does have a pronounced influence on the crystal growth step and, therefore, on the crystal growth rate, size, and morphology. The results presented here confirm a common mechanism proposed for organic-mediated crystallization of high-silica zeolites.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jp0006476DOIArticle
http://pubs.acs.org/doi/abs/10.1021/jp0006476PublisherArticle
Additional Information:© 2000 American Chemical Society. Received: February 18, 2000; In Final Form: May 18, 2000. Publication Date (Web): July 22, 2000.
Issue or Number:32
Record Number:CaltechAUTHORS:20170419-111654124
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170419-111654124
Official Citation:Si-MFI Crystallization Using a “Dimer” and “Trimer” of TPA Studied with Small-Angle X-ray Scattering Peter-Paul E. A. de Moor, Theo P. M. Beelen, Rutger A. van Santen, Larry W. Beck, and Mark E. Davis The Journal of Physical Chemistry B 2000 104 (32), 7600-7611 DOI: 10.1021/jp0006476
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76683
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:19 Apr 2017 18:25
Last Modified:03 Oct 2019 17:04

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