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Catalysis by framework zinc in silica-based molecular sieves

Orazov, Marat and Davis, Mark E. (2016) Catalysis by framework zinc in silica-based molecular sieves. Chemical Science, 7 (3). pp. 2264-2274. ISSN 2041-6520. PMCID PMC5977500. doi:10.1039/C5SC03889H. https://resolver.caltech.edu/CaltechAUTHORS:20160119-110838113

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Abstract

Microporous and mesoporous zincosilicates (e.g., CIT-6, VPI-8, Zn-MFI, and Zn-MCM-41) synthesized in the presence of alkali cations contain two broad types of Zn sites: one that is a dication analog of the monocation ion-exchangeable Al-site in aluminosilicates, while the other resembles isolated Zn sites on amorphous silica. The ratio of these sites varies, depending on the synthesis conditions of the zincosilicate. Post-synthetic strategies based on ion-exchange can alter the site distribution towards either population. Furthermore, post-synthetic introduction of isolated Zn sites of the latter type is possible for materials possessing silanol nests. Both types of sites behave as Lewis acid centers in probe-molecule IR spectroscopy, but have very different catalytic properties. Due to the unusually high adsorption energies of Lewis bases on such materials, Lewis acid catalysis is difficult at low temperatures and in solvents bearing Lewis basic functionality. However, at high temperatures, in hydrocarbon solvents, CIT-6 (Zn-beta) is able to selectively catalyze the Lewis-acid-catalyzed Diels–Alder cycloaddition–dehydration reactions of ethylene with methyl 5-(methoxymethyl)furan-2-carboxylate, a furan that can be derived quantitatively by partial oxidation of biomass-based 5-hydroxymethylfurfural. Additionally, zinc in silica-based molecular sieves is shown here to enable chemistries previously not accessible with framework Sn-, Ti- and Zr-based Lewis acid sites, e.g., the direct production of dimethyl terephthalate by Diels–Alder cycloaddition–dehydration reactions of ethylene and the dimethyl ester of furan-2,5-dicarboxilic acid.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1039/C5SC03889H DOIArticle
http://pubs.rsc.org/en/content/articlelanding/2016/sc/c5sc03889hPublisherArticle
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5977500PubMed CentralArticle
ORCID:
AuthorORCID
Davis, Mark E.0000-0001-8294-1477
Additional Information:© 2016 The Royal Society of Chemistry. Received 14th October 2015. Accepted 4th January 2016. First published online 04 Jan 2016. This work was financially supported as part of the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DESC0001004. M. O. acknowledges funding from the National Science Foundation Graduate Research Fellowship Program under Grant DGE-1144469. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. We thank Dr Stacey I. Zones (Chevron Energy Technology Company) for supplying the structure directing agent used in the synthesis of SSZ-33 and for helpful discussions, Dr Mona Shahgholi (Caltech) for the use of GC-MS, and Dr Joshua Pacheco and Dr Mark Deimund for helpful discussions regarding the technical aspects of Diels–Alder reactions and CIT-6 synthesis, respectively. All publication charges for this article have been paid for by the Royal Society of Chemistry.
Funders:
Funding AgencyGrant Number
Department of Energy (DOEDE-SC0001004
NSF Graduate Research FellowshipDGE-1144469
Royal Society of ChemistryUNSPECIFIED
Issue or Number:3
PubMed Central ID:PMC5977500
DOI:10.1039/C5SC03889H
Record Number:CaltechAUTHORS:20160119-110838113
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20160119-110838113
Official Citation:Catalysis by framework zinc in silica-based molecular sieves Marat Orazov and Mark E. Davis Chem. Sci., 2016, 7, 2264-2274 DOI: 10.1039/C5SC03889H DOI: 10.1039/C5SC03889H First published online : 04 Jan 2016
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63765
Collection:CaltechAUTHORS
Deposited By:INVALID USER
Deposited On:19 Jan 2016 22:33
Last Modified:13 May 2022 00:22

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