Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2017.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2017
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| Online Access: | http://hdl.handle.net/1721.1/111405 |
| _version_ | 1826208696693161984 |
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| author | Lewis, Jennifer Danielle |
| author2 | Yuriy Román-Leshkov. |
| author_facet | Yuriy Román-Leshkov. Lewis, Jennifer Danielle |
| author_sort | Lewis, Jennifer Danielle |
| collection | MIT |
| description | Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2017. |
| first_indexed | 2024-09-23T14:10:22Z |
| format | Thesis |
| id | mit-1721.1/111405 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T14:10:22Z |
| publishDate | 2017 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/1114052019-04-10T22:52:13Z Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites Lewis, Jennifer Danielle Yuriy Román-Leshkov. Massachusetts Institute of Technology. Department of Chemical Engineering. Massachusetts Institute of Technology. Department of Chemical Engineering. Chemical Engineering. Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemical Engineering, 2017. Vita. Page 203 blank. Cataloged from PDF version of thesis. Includes bibliographical references (pages 181-198). Zeolites containing Sn, Ti, Zr, or Hf heteroatoms are versatile catalysts for the activation and conversion of oxygenated molecules owing to the unique Lewis acid character of their tetrahedral metal sites. Through fluoride-mediated synthesis, hydrophobic Lewis acid zeolites can behave as water-tolerant catalysts, which has resulted in a recent surge of experimental and computational studies in the field of biomass conversion. However, many open questions still surround these materials, especially relating to the nature of their active sites. This thesis reports on studies that aim to understand the reactivity, deactivation, and active site speciation for Lewis acid zeolites. First, Hf-, Zr- and Sn-Beta zeolites are shown to effectively catalyze the coupled transfer hydrogenation and etherification of 5-(hydroxymethyl)-furfural with primary and secondary alcohols into 2,5-bis(alkoxymethyl) furans, thus making it possible to generate renewable fuel additives without the use of external hydrogen sources or precious metals. Continuous flow experiments reveal nonuniform changes in the relative deactivation rates of the transfer hydrogenation and etherification reactions. "9Sn and 29Si magic-angle spinning nuclear magnetic resonance (NMR) studies show that this deactivation can be attributed to changes in the local environment of the metal sites. Next, Lewis acid zeolites are shown to catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through a-proton abstraction. These Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions, enabling synthesis of unsaturated dicarboxylic acid esters via aldol condensation of keto esters. Finally, Lewis acid zeolite active sites are characterized by adsorbing trimethylphosphine oxide (TMPO) and recording quantitative 31P solid-state NMR spectra of the TMPO probe molecule. The 31P spectra provide active site concentrations that can be correlated to catalytic activity. Overall, the method developed can be used to characterize and quantify the active sites of low-defect Lewis acidic zeolites regardless of heteroatom identity. by Jennifer Danielle Lewis. Ph. D. 2017-09-15T15:32:43Z 2017-09-15T15:32:43Z 2017 2017 Thesis http://hdl.handle.net/1721.1/111405 1003291989 eng MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 203 pages application/pdf Massachusetts Institute of Technology |
| spellingShingle | Chemical Engineering. Lewis, Jennifer Danielle Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites |
| title | Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites |
| title_full | Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites |
| title_fullStr | Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites |
| title_full_unstemmed | Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites |
| title_short | Cooperative activation of biomass-derived oxygenates with Lewis acid zeolites |
| title_sort | cooperative activation of biomass derived oxygenates with lewis acid zeolites |
| topic | Chemical Engineering. |
| url | http://hdl.handle.net/1721.1/111405 |
| work_keys_str_mv | AT lewisjenniferdanielle cooperativeactivationofbiomassderivedoxygenateswithlewisacidzeolites |