Delamination of Layered Zeolite Precursors under Mild Conditions: Synthesis of UCB-1 via Fluoride/Chloride Anion-Promoted Exfoliation
Abstract
New material UCB-1 is synthesized via the delamination of zeolite precursor MCM-22 (P) at pH 9 using an aqueous solution of cetyltrimethylammonium bromide, tetrabutylammonium fluoride, and tetrabutylammonium chloride at 353 K. Characterization by powder X-ray diffraction, transmission electron microscopy, and nitrogen physisorption at 77 K indicates the same degree of delamination in UCB-1 as previously reported for delaminated zeolite precursors, which require a pH of greater than 13.5 and sonication in order to achieve exfoliation. UCB-1 consists of a high degree of structural integrity via ^(29)Si MAS NMR and Fourier transform infrared spectroscopies, and no detectable formation of amorphous silica phase via transmission electron microscopy. Porosimetry measurements demonstrate a lack of hysteresis in the N_2 adsorption/desorption isotherms and macroporosity in UCB-1. The new method is generalizable to a variety of Si:Al ratios and leads to delaminated zeolite precursor materials lacking amorphization.
Additional Information
© 2011 American Chemical Society. Received: December 10, 2010. Article ASAP February 22, 2011. Published In Issue March 16, 2011. We acknowledge Prof. Enrique Iglesia for generosity in resources and for useful discussion about porosity in these types of materials, Dr. Alexander Kuperman at Chevron for helpful discussion regarding delamination mechanism, and Dr. Anja Rumplecker for assistance in the syntheses of MCM-22 (P) and ITQ-2 zeolites. We are grateful to the Management and Transfer of Hydrogen via Catalysis Program funded by Chevron Corporation for financial support. The NMR facility at Caltech is supported by the National Science Foundation (NSF) under the Grant Number 9724240 and partially supported by the MRSEC program of NSF under Award Number DMR-520565.Attached Files
Supplemental Material - ja111147z_si_001.pdf
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Additional details
- Eprint ID
- 23234
- Resolver ID
- CaltechAUTHORS:20110404-110402712
- Chevron Corporation
- DMR-9724240
- NSF
- DMR-520565
- NSF
- Created
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2011-06-23Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field