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Substitution of Cetyltrimethylammonium for OSDA Cations During B-SSZ-70 Zeotype Synthesis and Its Influence on Delamination

Ramamurthy, Maya and Grosso-Giordano, Nicolás A. and Hwang, Son-Jong and Xu, Le and Xie, Dan and Mishra, Manish and Okrut, Alexander and Zones, Stacey and Katz, Alexander (2021) Substitution of Cetyltrimethylammonium for OSDA Cations During B-SSZ-70 Zeotype Synthesis and Its Influence on Delamination. Microporous and Mesoporous Materials, 319 . Art. No. 111042. ISSN 1387-1811. doi:10.1016/j.micromeso.2021.111042. https://resolver.caltech.edu/CaltechAUTHORS:20210322-094336661

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Abstract

We investigated the substitution of structure-directing agent diisobutylimidazolium hydroxide with cetyltrimethylammonium hydroxide (CTA⁺OH⁻) surfactant in the synthesis gel of layered-zeotype-precursor B-SSZ-70(P). At low substitution levels, CTA⁺ interacts with the external-zeotype surface, where it assembles. At higher surfactant amounts, CTA⁺ intercalation occurs, leading to swelling of the precursor material, as evidenced by powder X-ray diffraction. Characterization of adsorbed CTA⁺ cations by ¹³C MAS NMR spectroscopy demonstrates unique broad resonances in the intercalated layers, which represent a more rigid environment than in the external-surface assemblies. At still higher CTA⁺ substitution levels in the synthesis gel, we observe the formation of amorphous mesoporous silica. We attempted to delaminate materials synthesized with varying CTA⁺ substitution levels using mild conditions, in which the conventional sonication step is replaced with an easy-to-scale high-shear mixing, and in which the use of halide reagents, which are corrosive and have been required in the past, is also avoided. Our data demonstrate that synthesis of a swollen material per se is not essential as an intermediate for delamination, and that layered zeolite precursor swelling can actually undermine zeolite delamination. Our results instead point to the CTA⁺ external-surface assemblies as facilitating ease of SSZ-70 delamination under these mild conditions. When calcined and functionalized with grafted titanium centers, the delaminated materials are highly active and selective olefin epoxidation catalysts with organic hydroperoxides, showing a 40% higher epoxide conversion than a catalyst prepared from conventional B-SSZ-70.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.micromeso.2021.111042DOIArticle
ORCID:
AuthorORCID
Ramamurthy, Maya0000-0003-2882-9024
Grosso-Giordano, Nicolás A.0000-0002-0912-366X
Hwang, Son-Jong0000-0002-3210-466X
Xu, Le0000-0002-9727-7713
Xie, Dan0000-0003-2467-976X
Okrut, Alexander0000-0002-0689-4346
Katz, Alexander0000-0003-3487-7049
Additional Information:© 2021 Elsevier Inc. Received 6 January 2021, Revised 8 March 2021, Accepted 12 March 2021, Available online 18 March 2021. The authors gratefully acknowledge funding from the National Science Foundation Small Business Innovation Research Program (NSF-SBIR, Award No. 1746827) for materials synthesis,the U.S. Department of Energy (DE-FG02-05ER15696) for the catalysis portion of this work, and the Chevron Corporation Transfer of Hydrogen via Catalysis Program for materials characterization. CRediT authorship contribution statement: Maya Ramamurthy: Investigation, Visualization, Writing – original draft, Writing – review & editing. Nicolás A. Grosso-Giordano: Investigation. Son-Jong Hwang: Investigation. Le Xu: Investigation, Writing – review & editing. Dan Xie: Investigation. Manish Mishra: Investigation. Alexander Okrut: Investigation, Visualization, Writing – review & editing. Stacey Zones: Writing – review & editing, Conceptualization, Supervision. Alexander Katz: Conceptualization, Supervision, Writing – review & editing. The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Funders:
Funding AgencyGrant Number
NSFIIP-1746827
Department of Energy (DOE)DE-FG02-05ER15696
Subject Keywords:Zeolite delamination; Epoxidation catalysis; Co-structure directing agent
DOI:10.1016/j.micromeso.2021.111042
Record Number:CaltechAUTHORS:20210322-094336661
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20210322-094336661
Official Citation:Maya Ramamurthy, Nicolás A. Grosso-Giordano, Son-Jong Hwang, Le Xu, Dan Xie, Manish Mishra, Alexander Okrut, Stacey Zones, Alexander Katz, Substitution of Cetyltrimethylammonium for OSDA Cations During B-SSZ-70 Zeotype Synthesis and Its Influence on Delamination, Microporous and Mesoporous Materials, Volume 319, 2021, 111042, ISSN 1387-1811, https://doi.org/10.1016/j.micromeso.2021.111042. (https://www.sciencedirect.com/science/article/pii/S1387181121001682)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108501
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:24 Mar 2021 19:20
Last Modified:08 Apr 2021 15:05

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