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Steam-dealuminated, OSDA-free RHO and KFI-type zeolites as catalysts for the methanol-to-olefins reaction

Ji, Yuewei and Birmingham, John and Deimund, Mark A. and Brand, Stephen K. and Davis, Mark E. (2016) Steam-dealuminated, OSDA-free RHO and KFI-type zeolites as catalysts for the methanol-to-olefins reaction. Microporous and Mesoporous Materials, 232 . pp. 126-137. ISSN 1387-1811. http://resolver.caltech.edu/CaltechAUTHORS:20160627-084015068

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Abstract

RHO and KFI-type zeolites are synthesized in the absence of organic structure-directing agents (OSDAs), post-synthetically dealuminated via high temperature (600–800 °C) steam treatments, and evaluated as catalysts for converting methanol-to-light olefins (MTO). The proton forms of the as-made zeolites deactivate rapidly when tested for the MTO reaction (conducted at 400 °C and atmospheric pressure) due to their high aluminum content. Steam treatments lead to improvements in olefin selectivities and catalyst lifetimes with samples steamed at 600 °C giving the best combination of lifetime and olefin selectivity. Zeolite characterizations by ^(27)Al NMR, ^(29)Si NMR and argon physisorption indicate that the steam treatments extract framework aluminum, leading to reductions in the total number of Brønsted acid sites and the creation of mesopores that can facilitate transport of reactants. Poisoning of the acid sites external to the 8MR pores of the zeolites by treatments with trimethylphosphite results in longer catalyst lifetimes but do not affect the observed olefin selectivities, suggesting that olefins do not undergo secondary dimerization or methylation reactions at these sites.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.micromeso.2016.06.012DOIArticle
http://www.sciencedirect.com/science/article/pii/S1387181116302062PublisherArticle
Additional Information:© 2016 Elsevier Inc. Received 11 May 2016; Received in revised form 8 June 2016; Accepted 9 June 2016; Available online 11 June 2016. We would like to thank the Dow Chemical Company for financial support of this work (227027AJ).
Funders:
Funding AgencyGrant Number
Dow Chemical Company227027AJ
Subject Keywords:Methanol-to-olefins; RHO; KFI; Steaming; Phosphorous modification
Record Number:CaltechAUTHORS:20160627-084015068
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160627-084015068
Official Citation:Yuewei Ji, John Birmingham, Mark A. Deimund, Stephen K. Brand, Mark E. Davis, Steam-dealuminated, OSDA-free RHO and KFI-type zeolites as catalysts for the methanol-to-olefins reaction, Microporous and Mesoporous Materials, Volume 232, 15 September 2016, Pages 126-137, ISSN 1387-1811, http://dx.doi.org/10.1016/j.micromeso.2016.06.012. (http://www.sciencedirect.com/science/article/pii/S1387181116302062)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68675
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:30 Jun 2016 16:31
Last Modified:30 Jun 2016 16:31

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