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27
2.2.2. Methanol
The process used to produce methanol is a well-understood, mature
technology utilizing synthesis gas (syn-gas), a mixture of carbon monoxide
and hydrogen.2 The syn-gas, generated by steam reforming of natural gas,
is reacted over a copper catalyst with a high selectivity for methanol
generation.3 Worldwide methanol production is nearly 12 billion gallons, with
roughly 10% produced in the United States.4
The major use of methanol is in synthesis of other chemicals,
particularly formaldehyde, acetic acid, and methyl tert-butyl ether (MTBE).4
Formaldehyde is used to produce other chemicals as well as a resin in the
production of wood products like plywood. Acetic acid is used in the
manufacturing of PETE, a common plastic used for beverage bottles. MTBE
is a fuel additive that enhances gasoline octane rating and helps gasoline
burn for completely. Unfortunately, MTBE easily contaminates ground water,
with high concentrations rendering it undrinkable. Several countries
including the United States, have phased out use of MTBE in gasoline in
favor of other oxygenates like ethanol.
Methanol supply and demand has been consistent for many years;
however, demand has decreased over the last decade. Elimination of MTBE
is a large part of the decrease, but an overall reduction in building projects
required less wood products thus less formaldehyde production. The current
oversupply of methanol would promote adoption of MTH technologies.
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 38 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 27 2.2.2. Methanol The process used to produce methanol is a well-understood, mature technology utilizing synthesis gas (syn-gas), a mixture of carbon monoxide and hydrogen.2 The syn-gas, generated by steam reforming of natural gas, is reacted over a copper catalyst with a high selectivity for methanol generation.3 Worldwide methanol production is nearly 12 billion gallons, with roughly 10% produced in the United States.4 The major use of methanol is in synthesis of other chemicals, particularly formaldehyde, acetic acid, and methyl tert-butyl ether (MTBE).4 Formaldehyde is used to produce other chemicals as well as a resin in the production of wood products like plywood. Acetic acid is used in the manufacturing of PETE, a common plastic used for beverage bottles. MTBE is a fuel additive that enhances gasoline octane rating and helps gasoline burn for completely. Unfortunately, MTBE easily contaminates ground water, with high concentrations rendering it undrinkable. Several countries including the United States, have phased out use of MTBE in gasoline in favor of other oxygenates like ethanol. Methanol supply and demand has been consistent for many years; however, demand has decreased over the last decade. Elimination of MTBE is a large part of the decrease, but an overall reduction in building projects required less wood products thus less formaldehyde production. The current oversupply of methanol would promote adoption of MTH technologies. |
