| Revision as of 16:52, 22 September 2011 editCheMoBot (talk | contribs)Bots141,565 edits Updating {{chembox}} (no changed fields - added verified revid - updated 'DrugBank_Ref', 'UNII_Ref', 'ChEMBL_Ref') per Chem/Drugbox validation (report errors or bugs)← Previous edit |
Latest revision as of 15:50, 19 January 2025 edit undoMinusBot (talk | contribs)Bots3,739 editsm Proper minus signs and other cleanup. Report bugs, errors, and suggestions at User talk:MinusBotTag: AWB |
| (233 intermediate revisions by more than 100 users not shown) |
| Line 1: |
Line 1: |
|
{{DISPLAYTITLE:Methyl ''tert''-butyl ether}} |
|
{{DISPLAYTITLE:Methyl ''tert''-butyl ether}} |
|
{{chembox |
|
{{chembox |
|
|
| Watchedfields = changed |
|
| verifiedrevid = 448762960 |
|
|
|
| verifiedrevid = 451874187 |
|
| Name = Methyl ''tert''-butyl ether |
|
|
|
| Name = {{nobr|Methyl ''tert''-butyl ether}} |
|
| ImageFileL1 = MTBE-2D-skeletal.png |
|
|
|
| ImageFile = MTBE-2D.svg |
|
| ImageSizeL1 = 120px |
|
|
|
| ImageSize = 150 |
|
| ImageNameL1 = Skeletal formula |
|
|
|
| ImageClass = skin-invert |
|
| ImageFileR1 = Methyl-tert-butyl-ether-3D-balls.png |
|
|
|
| ImageAlt = Skeletal formula of MTBE |
|
| ImageSizeR1 = 120px |
|
|
|
| ImageFile1 = Methyl tert-butyl ether 3D ball.png |
|
| ImageNameR1 = Ball-and-stick model |
|
|
|
| ImageSize1 = 150 |
|
| IUPACName = 2-Methoxy-2-methylpropane |
|
|
|
| ImageAlt1 = Ball-and-stick model of the MTBE molecule |
|
| OtherNames = Methyl ''tertiary''-butyl ether<br />Methyl ''tert''-butyl ether<br />Methyl ''t''-butyl ether<br />MTBE<br />''tert''-Butyl methyl ether<br />tBME<br />''tert''-BuOMe |
|
|
|
| PIN = 2-Methoxy-2-methylpropane |
|
| Section1 = {{Chembox Identifiers |
|
|
|
| OtherNames = {{ubl|Methyl ''tertiary''-butyl ether|Methyl ''t''-butyl ether|MTBE|''tert''-Butyl methyl ether|tBME|''tert''-BuOMe}} |
|
|
| Section1 = {{Chembox Identifiers |
|
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
|
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} |
|
| ChemSpiderID = 14672 |
|
| ChemSpiderID = 14672 |
| Line 25: |
Line 27: |
|
| CASNo_Ref = {{cascite|correct|CAS}} |
|
| CASNo_Ref = {{cascite|correct|CAS}} |
|
| CASNo = 1634-04-4 |
|
| CASNo = 1634-04-4 |
|
|
| UNII_Ref = {{fdacite|correct|FDA}} |
|
|
| UNII = 29I4YB3S89 |
|
| ChEBI_Ref = {{ebicite|correct|EBI}} |
|
| ChEBI_Ref = {{ebicite|correct|EBI}} |
|
| ChEBI = 27642 |
|
| ChEBI = 27642 |
|
| SMILES = O(C(C)(C)C)C |
|
| SMILES = O(C(C)(C)C)C |
|
}} |
|
}} |
|
| Section2 = {{Chembox Properties |
|
| Section2 = {{Chembox Properties |
|
| Formula = C<sub>5</sub>H<sub>12</sub>O |
|
| C=5|H=12|O=1 |
|
| MolarMass = 88.15 g/mol |
|
| Density = 0.7404 g/cm<sup>3</sup> |
|
|
| Appearance = colourless liquid |
|
| Density = 0.7404 g/cm³ |
|
|
|
| VaporPressure = 27kPa (20ºC) |
|
| MeltingPtC = -109 |
|
|
|
| Viscosity = 3.4·10<sup>−4</sup> Pa·s (at 25ºC) |
|
| BoilingPtC = 55.2 |
|
|
|
| MeltingPtC = -108.6 |
|
|
| BoilingPtC = 55.5 |
|
|
| Solubility = 26 g/L (20 °C)<ref name=GESTIS>{{GESTIS|ZVG=40480|Name=Methyl tert-butyl ether}}</ref> |
|
}} |
|
}} |
|
| Section7 = {{Chembox Hazards |
|
| Section7 = {{Chembox Hazards |
|
| FlashPt = -10 °C |
|
| NFPA-H = 2 |
|
| NFPA-H = 1 |
|
| NFPA-F = 3 |
|
| NFPA-F = 3 |
|
| NFPA-I = 0 |
|
| NFPA-R = |
|
| FlashPtC = -32.78 |
|
|
| AutoignitionPtC = 435 |
|
}} |
|
}} |
|
}} |
|
}} |
|
|
|
|
|
'''Methyl ''tert''-butyl ether''', also known as '''methyl tertiary butyl ether''' and '''MTBE''', is an ] with molecular formula (CH<sub>3</sub>)<sub>3</sub>COCH<sub>3</sub>. MTBE is a volatile, flammable, and colorless liquid that is ] with water. It has a minty odor vaguely reminiscent of ], leading to unpleasant taste and odor in water. MTBE is a ] additive, used as an ] to raise the ]. Its use is controversial in the US and declining in that country in part because of its occurrence in ] and legislation favoring ethanol. Worldwide production of MTBE has been constant at about 18 million tons/y (2005) owing to growth in Asian markets which are less subject to ethanol subsidies.<ref>M. Winterberg, E. Schulte-Korne, U. Peters, F. Nierlich "Methyl Tert-Butyl Ether" in Ullmann's Encyclopedia of Industrial Chemistry, 2010, Wiley-VCH, Weinheim. {{DOI|10.1002/14356007.a16_543.pub2}}</ref> |
|
'''Methyl ''tert''-butyl ether''' ('''MTBE'''), also known as '''''tert''-butyl methyl ether''', is an ] with a structural formula (CH<sub>3</sub>)<sub>3</sub>COCH<sub>3</sub>. MTBE is a volatile, flammable, and colorless liquid that is sparingly soluble in water.<ref name=GESTIS /> Primarily used as a fuel additive, MTBE is blended into ] to increase its ] and ], and reduce unwanted ].<ref>{{Cite web |title=Methyl tertiary butyl ether prices, markets & analysis |url=https://www.icis.com/explore/commodities/chemicals/methyl-tertiary-butyl-ether/ |access-date=2020-06-28 |website=ICIS Explore |language=en-US}}</ref><ref>{{Cite web |title=Oxygenates |url=https://www.api.org:443/oil-and-natural-gas/environment/clean-water/ground-water/oxygenates |access-date=2020-06-28 |website=www.api.org |language=en}}</ref> |
|
|
|
|
|
==Production and properties== |
|
==Production and properties== |
|
|
MTBE is manufactured via the ] of ] and ]. Methanol is primarily derived from ],<ref>{{Cite web |title=How is Methanol Produced |url=https://www.methanol.org/methanol-production/ |access-date=2020-06-29 |website=METHANOL INSTITUTE |language=en-US}}</ref> where ] converts the various light hydrocarbons in natural gas (primarily methane) into carbon monoxide and hydrogen.<ref>{{Cite journal |last1=Anzelmo |first1=Bryce |last2=Wilcox |first2=Jennifer |last3=Liguori |first3=Simona |title=Hydrogen production via natural gas steam reforming in a Pd-Au membrane reactor. Investigation of reaction temperature and GHSV effects and long-term stability |url=https://users.wpi.edu/~jlwilcox/documents/bryce_hpv.pdf |journal=Journal of Membrane Science |pages=25–32 }}{{Dead link|date=October 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> The resulting gases then further react in the presence of a catalyst to form methanol.<ref>{{Cite web |title=methanol {{!}} Properties, Production, Uses, & Poisoning |url=https://www.britannica.com/science/methanol |access-date=2020-06-29 |website=Encyclopedia Britannica|language=en}}</ref> Isobutylene can be produced through a variety of methods. ] can be isomerized into ] which can be dehydrogenated to isobutylene.<ref>{{Cite web |title=Methyl Tertiary Butyl Ether (MTBE) Production and Manufacturing Process |url=https://www.icis.com/explore/resources/news/2007/11/05/9076055/methyl-tertiary-butyl-ether-mtbe-production-and-manufacturing-process |access-date=2020-06-29 |website=ICIS Explore |language=en-US}}</ref> In the Halcon process, ''t''-Butyl hydroperoxide derived from isobutane oxygenation is treated with ] to produce ] and ]. The ''t''-butanol can be dehydrated to isobutylene. |
|
MTBE is manufactured via the ] of ] and ]. Methanol is derived from natural gas, and isobutylene is derived from ] obtained from ] or ], thus MTBE is derived from fossil fuels. In the United States, it was produced in very large quantities (more than {{convert|200000|oilbbl|m3}} per day in 1999) during its use as a fuel additive. |
|
|
|
|
|
|
MTBE production across the globe has been steady because of its positive impact on engine performance.<ref name="Ullmann2">Werner Dabelstein, Arno Reglitzky, Andrea Schütze and Klaus Reders "Automotive Fuels" in ''Ullmann's Encyclopedia of Industrial Chemistry'' 2007, Wiley-VCH, Weinheim. {{doi|10.1002/14356007.a16_719.pub2}}</ref> The global demand has been mainly driven by growing Asian markets.<ref>{{Cite book |last=Elvers |first=Barbara |url=https://books.google.com/books?id=CN4_EAAAQBAJ&pg=PA419 |title=Handbook of Fuels: Energy Sources for Transportation |last2=Schütze |first2=Andrea |date=2021-12-20 |publisher=John Wiley & Sons |isbn=978-3-527-33385-1 |language=en}}</ref> Chinese capacity grew from ~18 million metric tons in 2017<ref>{{Cite web |last=Huang |first=Winnie |title=OUTLOOK '18: China biofuel promotion may hit domestic MTBE market |url=https://www.icis.com/explore/resources/news/2018/01/02/10178676/outlook-18-china-biofuel-promotion-may-hit-domestic-mtbe-market/ |access-date=2025-01-08 |website=ICIS Explore |language=en-US}}</ref> to ~22 millions in 2023, with actual production standing at ~16 millions in the same year.<ref>{{Cite web |title=SunSirs: China MTBE Market is on the Rise in 2023, What is the trend in 2024? |url=https://www.sunsirs.com/uk/detail_news-16659.html |access-date=2025-01-08 |website=www.sunsirs.com}}</ref> |
|
|
|
|
|
===US perspective=== |
|
|
Under pressure from the bioethanol lobby,<ref name="Ullmann2"/> production of MTBE in the U.S. peaked in 1999 at 260,000 barrels per day<ref name=":0">{{Cite web |title=The United States continues to export MTBE, mainly to Mexico, Chile, and Venezuela - Today in Energy - U.S. Energy Information Administration (EIA)|url=https://www.eia.gov/todayinenergy/detail.php?id=36614 |access-date=2020-06-28 |website=www.eia.gov}}</ref> before dropping down due to ] to about 50,000 barrels per day and holding steady,<ref>{{Cite web |title=United States {{!}} Methyl Tertiary Butyl Ether (MTBE): Production {{!}} Economic Indicators |url=https://www.ceicdata.com/en/united-states/production/methyl-tertiary-butyl-ether-mtbe-production |access-date=2020-06-28 |website=www.ceicdata.com}}</ref> mostly for the export market. After the purchase of ],<ref>{{Cite web |title=Aramco completes its acquisition of a 70% stake in SABIC from the Public Investment Fund (PIF) |url=https://www.saudiaramco.com/en/news-media/news/2020/saudi-aramco-completes-acquisition-of-70-percent-stake-in-sabic |access-date=2020-06-29 |website=www.saudiaramco.com |date=17 June 2020 |language=en}}</ref><ref>{{Cite news |date=2020-06-14 |title=Saudi Aramco buys SABIC shares on market as it completes acquisition |language=en |work=Reuters |url=https://www.reuters.com/article/us-saudi-sabic-deals-idUSKBN23L0EQ |access-date=2020-06-29}}</ref> oil giant ] is now considered to be the world's largest producer<ref>{{Cite web |title=Saudi Aramco to have largest MTBE capacity in Middle East and Asia |url=https://www.nsenergybusiness.com/news/saudi-aramco-mtbe-capacity-middle-east-asia/ |access-date=2020-06-29 |language=en-US}}</ref> with an estimated production capacity of 2.37 million metric tons per year (mt/yr).<ref>{{Cite web |date=2019-04-09 |title=Saudi Aramco's MTBE trading volume likely to rise after Sabic purchase {{!}} S&P Global Platts |url=https://www.spglobal.com/platts/en/market-insights/latest-news/oil/040919-saudi-aramcos-mtbe-trading-volume-likely-to-rise-after-sabic-purchase |access-date=2020-06-29 |website=www.spglobal.com |language=en}}</ref> Worldwide production capacity of MTBE in 2018 was estimated to be 35 million metric tons.<ref>{{Cite web |title=MTBE annual production capacity globally 2023 |url=https://www.statista.com/statistics/1067431/mtbe-production-capacity-globally/ |access-date=2020-06-28 |website=Statista |language=en}}</ref> |
|
|
|
|
|
==Uses== |
|
==Uses== |
|
MTBE is almost exclusively used as a fuel component in fuel for ] engines. It is one of a group of chemicals commonly known as ]s because they raise the ] content of gasoline. |
|
MTBE is used as a fuel component in fuel for ] engines. It is one of a group of chemicals commonly known as ]s because they raise the ] content of gasoline. |
|
|
|
|
|
===As anti-knocking agent=== |
|
===As anti-knocking agent=== |
|
In the US it has been used in gasoline at low levels since 1979 to replace ] and to increase its ] helping prevent ]. Oxygenates help gasoline burn more completely, ] from pre-1984 motor vehicles; dilutes or displaces gasoline components such as aromatics (e.g., ]) and sulfur; and optimizes the oxidation during combustion. Most refiners chose MTBE over other oxygenates primarily for its blending characteristics and low cost. |
|
In the U.S. MTBE has been used in gasoline at low levels since 1979, replacing ] (TEL) as an antiknock (octane rating) additive to prevent ].<ref>{{Cite web |title=Overview {{!}} Methyl Tertiary Butyl Ether (MTBE) {{!}} US EPA |url=https://archive.epa.gov/mtbe/web/html/faq.html |access-date=2021-04-07 |website=archive.epa.gov |language=en}}</ref> Oxygenates also help gasoline burn more completely, ]. Oxygenates also dilute or displace gasoline components such as aromatics (e.g., ]). Before the introduction of other oxygenates and octane enhancers, refiners chose MTBE for its blending characteristics and low cost. |
|
|
|
|
|
====Alternatives to MTBE as an anti-knock agent==== |
|
===Alternatives to MTBE as an anti-knock agent=== |
|
Other compounds are available as additives for gasoline including ] and some ethers such as ] (TAME). |
|
Other oxygenates are available as additives for gasoline including ] and other ethers such as ]. |
|
|
|
|
|
Ethanol has been advertised as a safe alternative by the agricultural interest groups in the USA and Europe. Its lack of toxicity is not different from MTBE, but as a polar solvent, it drives off nonpolar hydrocarbons from the gasoline, a problem that MTBE does not cause. Some volatile hydrocarbons in gasoline vapors are ]s, and gasoline vapors produce ]. Ethanol's higher cost requires government intervention in the form of subsidies or mandated usage to be competitive. In 2003, California was the first U.S. state to start replacing MTBE with ethanol. Several other states started switching soon thereafter. |
|
Ethanol has been advertised as a safe alternative by agricultural and other interest groups in the U.S. and Europe. In 2003, California was the first U.S. state to start replacing MTBE with ethanol. |
|
|
|
|
|
|
An alternative to ethanol is ETBE, which is manufactured from ethanol and isobutene. Its performance as an additive is similar to MTBE, but due to the higher price of ethanol compared to methanol, it is more expensive. |
|
Advocates of both sides of the debate in the United States sometimes claim that gasoline manufacturers have been forced to add MTBE to gasoline by law. It might be more correct to say they have been induced to do so, although any ] would fulfill the law. |
|
|
|
|
|
|
|
Higher quality gasoline is also an alternative, so that additives such as MTBE are unnecessary. ] itself is used. MTBE plants can be retrofitted to produce iso-octane from isobutylene.<ref name=nesteengineering>{{cite web |url=http://www.nesteengineering.com/default.asp?path=111,360,362,477 |title= NExOCTANE™ - Neste Jacobs |website=www.nesteengineering.com |archive-url=https://web.archive.org/web/20060106041047/http://www.nesteengineering.com/default.asp?path=111%2C360%2C362%2C477 |archive-date=January 6, 2006}}</ref><ref name=halliburton>{{Cite web |url=http://www.halliburton.com/kbr/hydroChem/petroChem/nexoctane.jsp |title=KBR - NExOCTANE™ |access-date=2006-01-31 |archive-url=https://web.archive.org/web/20060106003915/http://www.halliburton.com/kbr/hydroChem/petroChem/nexoctane.jsp |archive-date=2006-01-06 |url-status=dead }}</ref> |
|
An alternative to straight ethanol is the related ether ], which is manufactured from ethanol and isobutene. Its performance as an additive is similar to MTBE, but due to the higher price of ethanol compared to methanol, it is more expensive. |
|
|
|
|
|
|
Higher quality gasoline is also an alternative, i.e., so that additives such as MTBE are unnecessary. ] itself is used. MTBE plants can be retrofitted to produce iso-octane from isobutylene.<ref name="http://www.nesteengineering.com/default.asp?path=111,360,362,477"></ref><sup>,</sup><ref name="http://www.halliburton.com/kbr/hydroChem/petroChem/nexoctane.jsp"></ref> |
|
|
===As a solvent=== |
|
===As a solvent=== |
|
|
MTBE is sometimes used as a solvent,<ref>{{cite journal |doi = 10.1194/jlr.D700041-JLR200 |doi-access=free |pmid = 18281723 |title = Lipid extraction by methyl-tert-butyl ether for high-throughput lipidomics |journal = ]| volume = 49 |issue = 5 |pages = 1137–1146 |year = 2008 |last1 = Matyash |first1 = V. |last2 = Liebisch |first2 = G. |last3 = Kurzchalia |first3 = T. V. |last4 = Shevchenko |first4 = A. |last5 = Schwudke |first5 = D. |pmc = 2311442}}</ref><ref>{{Cite journal |title = Sorption of methanol, dimethyl carbonate, methyl acetate, and acetone vapors in CTA and PTMSP: General findings from the GAB Analysis |journal = ] |date = 2016-03-01 |issn = 1099-0488 |pages = 561–569 |volume = 54 |issue = 5 |doi = 10.1002/polb.23945 |language = en |first1 = Ondřej |last1 = Vopička |first2 = Kryštof |last2 = Pilnáček |first3 = Petr |last3 = Číhal |first4 = Karel |last4 = Friess |bibcode = 2016JPoSB..54..561V}}</ref><ref>{{Cite journal |title = Sorption of vapour mixtures of methanol and dimethyl carbonate in PTMSP: Cooperative and competitive sorption in one system |journal = ] |date = 2016-02-01 |pages = 243–250 |volume = 75 |doi = 10.1016/j.eurpolymj.2015.12.015 |first1 = Ondřej |last1 = Vopička |first2 = Daniel |last2 = Radotínský |first3 = Karel |last3 = Friess}}</ref> although it is used less commonly than diethyl ether. Although an ether, MTBE is a poor ] and does not support formation of ]s. It is also unstable toward strong acids. It reacts dangerously with ].<ref>{{cite web |url=http://www.crhf.org.uk/incident09.html |title=Interaction between bromine and tert-butyl methyl ether |publisher=UK Chemical Reaction Hazards Forum |access-date=13 May 2010 |archive-url=https://web.archive.org/web/20110313064840/http://www.crhf.org.uk/incident09.html |archive-date=13 March 2011}}</ref> |
|
As a solvent, MTBE possesses one distinct advantage over most ethers - it has a reduced tendency to form explosive ]s. Opened bottles of ] or ] can build up dangerous levels of these peroxides in months, whereas samples of MTBE are usually safe for years (but they should still be tested periodically). For this reason (as well as its higher boiling point), MTBE is used as a solvent extensively in industry, where safety concerns and regulations make working with diethyl ether, THF, or other ethers much more difficult and expensive. However, despite the popularity of MTBE in industrial settings, it is rarely used as a solvent in academia with some exceptions.<ref>http://www.jlr.org/cgi/content/abstract/D700041-JLR200v1</ref> |
|
|
|
|
|
|
MTBE forms ]s with water (52.6 °C; 96.5% MTBE).<ref>http://www.zeon.co.jp/business_e/enterprise/spechemi/cpme_tec_sup_e_200906.pdf Zeon Corportation]</ref> and methanol (51.3 °C; 68.6% MTBE).<ref>CRC Handbook of Chemistry and Physics, 90th edition</ref> |
|
MTBE forms ]s with water (52.6 °C; 96.5% MTBE)<ref name=":1"> {{webarchive |url=https://web.archive.org/web/20110722102229/http://www.zeon.co.jp/business_e/enterprise/spechemi/cpme_tec_sup_e_200906.pdf |date=2011-07-22 }}</ref> and methanol (51.3 °C; 68.6% MTBE).<ref>'']'', 90th edition</ref> The solubility of water in MTBE is reported to be 1.5 g/100g at 23 °C.<ref name=":1" /> |
|
|
|
|
|
|
In an investigational medical procedure called contact dissolution therapy, MTBE is injected directly into the gallbladder to dissolve cholesterol ]. Due to concerns of MTBE toxicity and potentially serious side effects in the event of solvent draining into the ], and the advent of ] techniques, this procedure is considered obsolete.<ref>{{cite journal |vauthors=Schoenfield LJ, Marks JW |title=Oral and contact dissolution of gallstones |journal=] |volume=165 |issue=4 |pages=427–30 |year=1993 |pmid=8480875 |doi=10.1016/S0002-9610(05)80934-1 }}</ref><ref>{{cite news |url = https://www.nytimes.com/health/guides/disease/gallstones/treatment.html |title = Health Guide: Gallstones |newspaper = New York Times}}</ref><ref>https://www.aetna.com/cpb/medical/data/500_599/0509.html | access-date = June 3, 2024</ref> |
|
Although an ether, MTBE is a poor ] and does not support formation of ]s. It is also unstable toward strong acids. It reacts dangerously with ].<ref>{{cite web|url=http://www.crhf.org.uk/incident09.html|title=Interaction between bromine and tert-butyl methyl ether|accessdate=13 May 2010}}</ref></blockquote> |
|
|
|
|
|
|
MTBE is used in organic chemistry as a relatively inexpensive solvent with properties comparable to diethyl ether, but with a higher boiling point and less solubility in water. As a solvent, MTBE has one distinct advantage over most ethers - it has a much lower tendency to form explosive organic peroxides. It is widely used as a solvent in industry where, for safety and regulatory reasons, handling diethyl ether or other ethers is much more difficult and expensive. MTBE as a solvent is used in the oil refining industry as a method for dewaxing waxy petroleum fractions. |
|
|
|
|
|
==Persistence and pervasiveness in the environment== |
|
==Persistence and pervasiveness in the environment== |
|
MTBE gives water an unpleasant taste at very low concentrations, and thus can render large quantities of groundwater non-potable. MTBE is often introduced into water-supply aquifers by leaking ]s (USTs) at gasoline stations or by gasoline containing MTBE spilled onto the ground. The higher water solubility and persistence of MTBE cause it to travel faster and farther than many other components of gasoline when released into an aquifer.<ref>http://www.handpmg.com/lustline31-mtbe-or-benzene.htm</ref><ref></ref> |
|
MTBE gives water an unpleasant taste at very low concentrations. MTBE often is introduced into water-supply ]s by leaking ]s (USTs) at gasoline stations or spills of gasoline. The higher water solubility and persistence of MTBE cause it to travel faster and farther than many other components of gasoline when released into an aquifer.<ref> {{webarchive |url=https://web.archive.org/web/20080229160231/http://www.swrcb.ca.gov/rwqcb2/download/WMI%202004%20Executive%20Summary.pdf |date=2008-02-29 }}</ref> |
|
|
|
|
|
MTBE is biodegraded by the action of bacteria. In the proper type of ], such as a ] bioreactor, MTBE can be rapidly and economically removed from water to undetectable levels. Activated carbon produced from coconut shells and optimized for MTBE adsorption can also reduce MTBE to undetectable levels.<ref name="Carbon: Optimized Activated Carbons for MTBE Removal in POU/POE Systems"> </ref> |
|
MTBE is biodegraded by the action of bacteria. In the proper type of ], such as a ] bioreactor, MTBE may be removed rapidly and economically from water to undetectable levels. ] produced from coconut shells and optimized for MTBE adsorption may reduce MTBE to undetectable levels,<ref name="Carbon: Optimized Activated Carbons for MTBE Removal in POU/POE Systems"> {{webarchive |url=https://web.archive.org/web/20110728081446/http://www.wcponline.com/pdf/spotlight.pdf |date=2011-07-28 }}</ref> although this level of reduction is likely to occur only in the most ideal circumstances. There are currently no known published cases of any in-situ treatment method that has been capable of reducing contaminant concentrations to baseline (pre-development) conditions within the aquifer soil matrix. |
|
|
|
|
|
|
According to the ] (IARC), a branch of the ], MTBE is not classified as a human ]. MTBE may be tasted in water at concentrations of 5–15 μg/L (5-15ppb).<ref>{{cite journal |journal = Environ Sci Pollut Res Int |year = 2005 |volume = 12 |issue = 6 |pages = 381–6 |title = Biotic and abiotic transformations of methyl tertiary butyl ether (MTBE) |vauthors = Fischer A, Oehm C, Selle M, Werner P |pmid = 16305145 |doi = 10.1065/espr2005.08.277 |s2cid = 97168152}}</ref> |
|
==Health risks== |
|
|
According to the ], a cancer research agency of the ], MTBE is not classified as a human ]. MTBE can be tasted in water at concentrations of 5 – 15 µg/l.<ref>{{cite journal |
|
|
| journal = Environ Sci Pollut Res Int |
|
|
| year = 2005 |
|
|
| volume = 12 |
|
|
| issue = 6 |
|
|
| pages = 381–6. |
|
|
| title = Biotic and abiotic transformations of methyl tertiary butyl ether (MTBE) |
|
|
| author = Fischer A, Oehm C, Selle M, Werner P. |
|
|
| pmid = 16305145 |
|
|
| doi = 10.1065/espr2005.08.277}}</ref> |
|
|
|
|
|
|
|
==Regulation and litigation in the U.S.== |
|
As of 2007, researchers have limited data about the health effects of ingestion of MTBE. The ] (EPA) has concluded that available data are inadequate to quantify health risks of MTBE at low exposure levels in drinking water, but that the data support the conclusion that MTBE is a potential human ] at high doses.<ref name="http://www.epa.gov/mtbe/faq.htm#concerns"></ref> |
|
|
|
{{main|MTBE controversy}} |
|
|
|
|
|
|
===Restrictions on MTBE manufacturing and use=== |
|
==Legislation and litigation in the U.S.== |
|
|
|
The ], as approved by the U.S. House of Representatives, did not include a provision for shielding MTBE manufacturers from ] lawsuits. This provision was first proposed in 2003 and had been thought by some to be a priority of ] and Rep. ], then chairman of the Energy and Commerce Committee.<ref> {{webarchive|url=https://web.archive.org/web/20050422043436/http://www.cnn.com/2005/POLITICS/04/21/energy.bill.mtbe.ap/ |date=2005-04-22 }}</ref> This bill did include a provision that gave MTBE makers, including some major ], $2 billion in transition assistance while MTBE was phased out over the following nine years.<ref>{{Cite web | url=https://www.nbcnews.com/id/wbna7574562 |title = House approves $12 billion energy package|website = ]|date = 2005-04-22}}</ref> Due to opposition in the Senate,<ref>Charles Babington, House Again Passes GOP Energy Measures, Washington Post, June 16, 2004, at A4 (House passes Energy Bill, but Senate opponents of MTBE provision in House Bill have the votes to prevent its enactment).</ref> the conference report dropped all MTBE provisions. The final bill was signed into law by President ].<ref>United States. Energy Policy Act of 2005. {{uspl|109|58}}. Approved 2005-08-08.</ref> The lack of MTBE liability protection is resulting in a switchover to the use of ethanol as a gasoline additive. |
|
{{main|Methyl tert-butyl ether controversy}} |
|
|
MTBE removal from groundwater and ] in the U.S. is estimated to cost from $1 ]<ref></ref> to $30 billion,<ref></ref> including removing the compound from aquifers and municipal water supplies and replacing leaky underground oil tanks. In one case, the cost to oil companies to clean up the MTBE in wells belonging to Santa Monica is estimated to exceed $200 million.<ref></ref> In another case, the City of New York estimated a $250 million cost for cleanup of a single wellfield in Queens, NY.<ref>{{cite news| url=http://www.nytimes.com/2009/10/20/science/earth/20exxon.html | work=The New York Times | title=City Awarded $105 Million in Exxon Mobil Lawsuit | first=Mireya | last=Navarro | date=2009-10-20 | accessdate=2010-05-12}}</ref> |
|
|
|
|
|
|
|
===Cleanup costs and litigation=== |
|
MTBE is banned in the US states of ] and ]. MTBE consumption, banned the chemical starting January 1, 2004, and as of September 2005, twenty-five states had signed legislation banning MTBE. (A table of state by state information, as of 2002, is available at the ] website.<ref></ref>) |
|
|
|
MTBE removal from groundwater and ] in the U.S. was estimated to cost from $1 ]<ref>{{cite web |url=http://www.sigma.org/wr/reports/05/050523.html |title=MTBE Cleanup Estimates |author=<!--Not stated--> |date=2005-05-23 |website=SIGMA Weekly Report |publisher=Society of Independent Gasoline Marketers of America (SIGMA) |location=Fairfax, VA |archive-url=https://web.archive.org/web/20091009071418/http://www.sigma.org/wr/reports/05/050523.html |archive-date=2009-10-09}}</ref> to US$30 ],<ref>{{cite web |url=http://www.mtbe-eresource.com/liu.cfm |title=Long Island Utility Fighting to Defeat MTBE Safe Harbor |author=<!--Not stated--> |date=2004-03-16 |website=The MTBE e-Resource |publisher=Napoli Bern, LLP |location=New York, NY |archive-url=https://web.archive.org/web/20071020072714/http://www.mtbe-eresource.com/liu.cfm |archive-date=2007-10-20}}</ref> including removing the compound from aquifers and municipal water supplies and replacing leaky underground oil tanks. In one case, the cost to oil companies to clean up the MTBE in wells belonging to the city of ] was estimated to exceed $200 million.<ref>{{cite web |url=http://www.ens-newswire.com/ens/feb2005/2005-02-17-09.html |title=Oil Companies Pay Santa Monica MTBE Cleanup Costs |author=<!--Not stated--> |date=2005-02-17 |website=Environment News Service |publisher=Ecology Prime Media, Inc.}}</ref> In another case, ] estimated a $250 million cost for cleanup of a single wellfield in the borough of ] in 2009.<ref>{{cite news| url=https://www.nytimes.com/2009/10/20/science/earth/20exxon.html |work=The New York Times |title=City Awarded $105 Million in Exxon Mobil Lawsuit |first=Mireya |last=Navarro |date=2009-10-20 | access-date=2010-05-12}}</ref> In 2013 a jury awarded the State of ] $236 million in damages in order to treat groundwater contaminated by MTBE.<ref>{{cite news |url=https://www.bloomberg.com/news/2013-04-09/exxon-mobile-is-found-neligent-in-new-hampshire-mtbe-use.html |work=Bloomberg |title=Exxon Mobil is Found Negligent in New Hampshire MTBE Use |first=Sarah |last=Earle |date=2013-04-09}}</ref> |
|
|
|
|
|
|
Many lawsuits are still pending regarding MTBE contamination of public and private drinking water supplies. |
|
In 2000, the U.S. EPA drafted plans to phase out the use of MTBE nationwide over four years. |
|
|
As of fall 2006, hundreds of lawsuits are still pending regarding MTBE contamination of public and private drinking water supplies. |
|
|
|
|
|
|
|
===Drinking water regulations=== |
|
The ], passed in the U.S. House of Representative, did not include a provision for shielding MTBE manufacturers from ] lawsuits. This provision was first proposed in 2003 and had been thought by some to be a priority of ] and Rep. ], then chairman of the Energy and Commerce Committee.<ref></ref> This bill did include a provision that gives MTBE makers, including some major ], $2 billion in transition assistance as MTBE is phased out over the next nine years.<ref></ref> Due to opposition in the Senate,<ref>Charles Babington, House Again Passes GOP Energy Measures, Washington Post, June 16, 2004, at A4 (House passes Energy Bill, but Senate opponents of MTBE provision in House Bill have the votes to prevent its enactment).</ref> the conference report dropped all MTBE provisions. The final bill was passed by both houses and signed into law by President Bush.<ref></ref> The lack of MTBE liability protection is resulting in a switchover to the use of ethanol as a gasoline additive. Some traders and consumer advocates are blaming this for an increase in gasoline prices.<ref></ref> |
|
|
|
EPA first listed MTBE in 1998 as a candidate for development of a national ] (MCL) standard in drinking water.<ref>EPA (1998-03-02). "Announcement of the Drinking Water Contaminant Candidate List." ''Federal Register'', {{usfr|63|10274}}</ref> The agency listed MTBE on its ] in 2022 but has not announced whether it will develop an MCL.<ref>EPA (2022-11-14). "Drinking Water Contaminant Candidate List 5―Final." ''Federal Register,'' {{USFR|87|68060}}</ref> |
|
|
EPA uses toxicity data in developing MCLs for ]s.<ref>{{cite web |url=https://www.epa.gov/dwregdev/how-epa-regulates-drinking-water-contaminants |title=How EPA Regulates Drinking Water Contaminants |author=<!--Not stated--> |date=2017-05-03 |publisher=EPA}}</ref> |
|
|
|
|
|
|
California established a state-level MCL for MTBE, 13 micrograms per liter, in 2000.<ref>{{cite web |url=https://www.waterboards.ca.gov/drinking_water/certlic/drinkingwater/MTBE.html |title=MTBE: Regulations and Drinking Water Monitoring Results |author=<!--Not stated--> |date=2014-08-04 |publisher=California State Water Resources Control Board |location=Sacramento, CA}}</ref> |
|
The U.S. EPA currently lists MTBE as a candidate for a maximum contaminant level (]) in drinking water.<ref name="epa"></ref> MCLs are determined by the EPA using ] data. |
|
|
|
|
|
|
==See also== |
|
==See also== |
|
*] (ETBE) |
|
*] (CPME) |
|
*] (TAME) |
|
*] |
|
|
*] |
|
|
*] (TAME) |
|
|
|
|
|
==References== |
|
==References== |
| Line 112: |
Line 120: |
|
|
|
|
|
==External links== |
|
==External links== |
|
* |
|
* |
|
* |
|
* |
|
* from ] |
|
|
* |
|
|
* |
|
|
* |
|
|
* |
|
|
* |
|
|
* |
|
|
* |
|
|
* |
|
|
|
|
|
|
{{motor fuel}} |
|
{{motor fuel}} |
| Line 128: |
Line 127: |
|
{{DEFAULTSORT:Methyl Tert-Butyl Ether}} |
|
{{DEFAULTSORT:Methyl Tert-Butyl Ether}} |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
] |
|
|
] |
|
] |
|
] |
|
] |
|
|
] |
|
|
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|
|
] |
|