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25
Chapter 2: Methanol-to-Olefin Catalysis
2.1. Methanol-to-Hydrocarbons Catalysis
Methanol-to-hydrocarbons (MTH) catalysis encompasses all the
processes utilizing methanol as a feedstock to generate hydrocarbon
products. The field of MTH was first developed as a means to make high-octane
gasoline from coal, but over time the process was refined to produce
other desirable products such as olefins necessary for plastic production.
Scheme 2.1 illustrates the progression involved in MTH catalyses.
Scheme 2.1. Methanol-to-Hydrocarbon Overview
Methanol can be made from natural gas in a process described in
Section 2.2.2. Natural gas is plentiful in many parts of the world, making it a
cost-effective starting material; however transporting the gas is difficult,
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 36 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 25 Chapter 2: Methanol-to-Olefin Catalysis 2.1. Methanol-to-Hydrocarbons Catalysis Methanol-to-hydrocarbons (MTH) catalysis encompasses all the processes utilizing methanol as a feedstock to generate hydrocarbon products. The field of MTH was first developed as a means to make high-octane gasoline from coal, but over time the process was refined to produce other desirable products such as olefins necessary for plastic production. Scheme 2.1 illustrates the progression involved in MTH catalyses. Scheme 2.1. Methanol-to-Hydrocarbon Overview Methanol can be made from natural gas in a process described in Section 2.2.2. Natural gas is plentiful in many parts of the world, making it a cost-effective starting material; however transporting the gas is difficult, |
