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26
requiring pressurization to liquid natural gas. Polymer resins however are
very easy to transport. Thus a facility, even in a remote location, with the
ability to generate polymer resins from natural gas would tap a relatively
unused source of fossil fuels. Full realization of these technologies
industrially could transform the manner in which chemicals and polymers are
produced worldwide.
2.2. Current Chemical Production
2.2.1. Plastics
Plastics are part of everyday life in current society with uses in
electronics, automobiles, household items, and product packaging to name
just a few. In the last 30 years, worldwide plastic production has nearly
quadrupled with close to 250 million tons produced annually.1 The primary
plastics used in these products are polyethylene-based (coded as numbers 1
and 2) and polypropene-based (number 5) plastics. Polyethylene-based
plastics are used extensively, primarily for soda bottles and milk jugs, while
polypropene-based plastics are typically food packaging containers and
medical supplies. The plastic monomers ethylene and propene are
predominately obtained as the light fractions in petroleum refining thus
directly linking plastics to petroleum. As demand for plastic products
increases and availability of crude oil decreases, an alternative means to
produce the monomers is not just desirable, but required.
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 37 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 26 requiring pressurization to liquid natural gas. Polymer resins however are very easy to transport. Thus a facility, even in a remote location, with the ability to generate polymer resins from natural gas would tap a relatively unused source of fossil fuels. Full realization of these technologies industrially could transform the manner in which chemicals and polymers are produced worldwide. 2.2. Current Chemical Production 2.2.1. Plastics Plastics are part of everyday life in current society with uses in electronics, automobiles, household items, and product packaging to name just a few. In the last 30 years, worldwide plastic production has nearly quadrupled with close to 250 million tons produced annually.1 The primary plastics used in these products are polyethylene-based (coded as numbers 1 and 2) and polypropene-based (number 5) plastics. Polyethylene-based plastics are used extensively, primarily for soda bottles and milk jugs, while polypropene-based plastics are typically food packaging containers and medical supplies. The plastic monomers ethylene and propene are predominately obtained as the light fractions in petroleum refining thus directly linking plastics to petroleum. As demand for plastic products increases and availability of crude oil decreases, an alternative means to produce the monomers is not just desirable, but required. |
