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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.

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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
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.
Funding AgencyGrant Number
Department of Energy (DOE)DE-FG02-05ER15696
Subject Keywords:Zeolite delamination; Epoxidation catalysis; Co-structure directing agent
Record Number:CaltechAUTHORS:20210322-094336661
Persistent URL:
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, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108501
Deposited By: Tony Diaz
Deposited On:24 Mar 2021 19:20
Last Modified:08 Apr 2021 15:05

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