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115
Figure 4.8. MTO with formaldehyde on various topologies. The GC-FID
chromatograms from the reaction of a solution of 18 moles of methanol with
1 mole of 1,3,5-trioxane (6 mole methanol to 1 mole formaldehyde) after 5
minutes time on stream are provided for 200 mg of a) H-Ferrierite (FER), b)
H-Beta (*BEA), and c) H-Mordenite (MOR), each if which was combined with
silicon carbide as described in Section 4.3.2. The methanol-aldehyde
solution was introduced into the reactor with a syringe pump with a methanol
flow rate of WHSV = 4 hr-1 and 648 K under 50 sccm of flowing helium.
Object Description
| Title | Modification of methanol-to-olefin hydrocarbon pool species by oxygenates on acidic zeolites |
| Author | Hayman, Miranda Jeanette |
| Author email | mirandah@usc.edu; mirandahayman@gmail.com |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Chemistry |
| School | College of Letters, Arts and Sciences |
| Date defended/completed | 2011-02-11 |
| Date submitted | 2011 |
| Restricted until | Unrestricted |
| Date published | 2011-04-26 |
| Advisor (committee chair) | Haw, James F. |
| Advisor (committee member) |
Flood, Thomas C. Jessen, Kristian |
| Abstract | The mechanism of methanol-to-olefin (MTO) catalysis employs organic reaction centers, both aromatic and olefinic, to generate olefins on acid zeolites. Generally, propene is the favored MTO olefin on most zeolite catalysts, but ethylene is a more desirable olefin due to its prevalence in consumer plastics. Much research has been conducted to alter the MTO product selectivities to favor ethylene. This focus of this dissertation is selective modification of the olefinic reaction centers, converting them into aromatic reaction centers known to be responsible for the majority of ethylene production.; Formaldehyde reactivity was studied on HSAPO-34, and found to react with propene through a Prins reaction to form butadiene, which readily cyclized to aromatic species. Evidence of formaldehyde formation was observed from methanol oxidation on the stainless-steel surface of the reactor tubing. This reaction was then studied in HZSM-5 where olefinic reaction centers dominate the hydrocarbon pool. The olefinic reaction centers were converted to aromatic species, and a significant increase in ethylene selectivity was observed. Other oxygenated species, such as acetaldehyde, were also studied in conjunction with methanol on HZSM-5 and an improvement in ethylene selectivity was noted. The consequence of the increased ethylene selectivity however was an increase in the rate of deactivation due to the accelerated formation of aromatic species. |
| Keyword | MTO; methanol-to-olefins; zeolite; heterogeneous catalysis; hydrocarbon pool; HZSM-5 |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m3780 |
| Contributing entity | University of Southern California |
| Rights | Hayman, Miranda Jeanette |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-Hayman-4358 |
| Archival file | uscthesesreloadpub_Volume23/etd-Hayman-4358.pdf |
Description
| Title | Page 126 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 115 Figure 4.8. MTO with formaldehyde on various topologies. The GC-FID chromatograms from the reaction of a solution of 18 moles of methanol with 1 mole of 1,3,5-trioxane (6 mole methanol to 1 mole formaldehyde) after 5 minutes time on stream are provided for 200 mg of a) H-Ferrierite (FER), b) H-Beta (*BEA), and c) H-Mordenite (MOR), each if which was combined with silicon carbide as described in Section 4.3.2. The methanol-aldehyde solution was introduced into the reactor with a syringe pump with a methanol flow rate of WHSV = 4 hr-1 and 648 K under 50 sccm of flowing helium. |
