tert-Butyl methyl ether
tert-Butyl methyl ether Chemical Properties
- Melting point:
- -110 °C
- Boiling point:
- 55-56 °C(lit.)
- vapor density
- 3.1 (vs air)
- vapor pressure
- 4.05 psi ( 20 °C)
- refractive index
- Flash point:
- -27 °F
- storage temp.
- Powder or Needles
- Specific Gravity
- APHA: ≤10
- Relative polarity
- Characteristic ethereal odor
- explosive limit
- Water Solubility
- 51 g/L (20 ºC)
- λ: 210 nm Amax: 1.0
λ: 225 nm Amax: 0.50
λ: 250 nm Amax: 0.10
λ: 300-400 nm Amax: 0.005
- Stable, but may form explosive peroxides in contact with air. Extremely flammable - note low flash point. Incompatible with strong oxidizing agents.
- CAS DataBase Reference
- 1634-04-4(CAS DataBase Reference)
- 3 (Vol. 73) 1999
- NIST Chemistry Reference
- Propane, 2-methoxy-2-methyl-(1634-04-4)
- EPA Substance Registry System
- Methyl tert-butyl ether (1634-04-4)
- Hazard Codes
- Risk Statements
- Safety Statements
- UN 2398 3/PG 2
- WGK Germany
- Autoignition Temperature
- 705 °F
- HS Code
- 2909 19 90
- Hazardous Substances Data
- 1634-04-4(Hazardous Substances Data)
- . LC50 in mice (15 min): 1.6 mmol/liter of atmosphere (Marsh)
tert-Butyl methyl ether Usage And Synthesis
Methyl tert-butyl ether (MTBE), also known as tert-butyl methyl ether, a colorless liquid, is an aliphatic ether and volatile organic compound (VOC). It is moderately soluble in water and very soluble in some organic solvents such as alcohol and diethylether (ATSDR, 1996). It is a flammable liquid with a characteristic odor.
Methyl Tertiary Butyl Ether (MTBE) was first commercially produced in Italy in 1973 for use as an octane enhancer in gasoline. U.S. production of MTBE started in 1979 after Atlantic Richfield Co. (ARCO) was granted a waiver by the U.S. Environmental Protection Agency (EPA) that allowed MTBE to be blended up to 7 vol % in U.S. unleaded gasoline. The use of other aliphatic ethers was allowed when the U.S. EPA issued its “substantially similar” definition for unleaded gasoline specifications in 1981. Under this definition, any aliphatic ether or ether mixture could be blended in unleaded gasoline as long as the total oxygen contribution from the ethers does not exceed 2.0% oxygen by weight in the gasoline. This allowed MTBE to be blended up to approximately 11 vol % in gasoline.
Methyl tert-butyl ether (MTBE) is a synthetic chemical with synonyms methyl tertiary-butyl ether, tert-butyl methyl ether, tertiary-butyl methyl ether, methyl-1,1-dimethylethyl ether, 2-methoxy-2-methylpropane, 2-methyl-2-methoxypropane, methyl t-butyl ether, and MTBE. It was primarily used as a gasoline additive in unleaded gasoline in the United States prior to 2005, in the manufacture of isobutene, and as a chromatographic eluent especially in high pressure liquid chromatography (ATSDR, 1996; HSDB, 2012). It is also a pharmaceutical agent and can be injected into the gallbladder to dissolve gallstones (ATSDR, 1996). As a result of its manufacture and use, MTBE may be released into the environment through various waste streams directly (IPCS, 1998; HSDB, 2012).
The predominant use for MTBE in the United States was as an oxygenate in unleaded gasoline promoting more complete burning of gasoline. Reformulated fuel with MTBE was widely used in the United States between 1992 and 2005 to meet the 1990 Clean Air Act Amendments (CAAA) requirements for reducing carbon monoxide (CO) and ozone (O3) levels.
Methyl tert-butyl ether is used as a gasoline additive. Octane booster in gasoline.Nearly all methyl tert-butyl ether produced in the United States is used as an additive in unleaded gasoline to increase octane levels and reduce carbon monoxide emissions.
Chromatographic eluent especially in HPLC. Suitable for pesticide residue analysis.
ChEBI: An ether having methyl and tert-butyl as the two alkyl components.
tert-butyl methyl ether can be prepared by the reaction of potassium tert-butoxide and bromomethane.
A colorless liquid with a distinctive anesthetic-like odor. Vapors are heavier than air and narcotic. Boiling point 131°F. Flash point 18°F. Less dense than water and miscible in water. Used as a octane booster in gasoline.
Air & Water Reactions
Highly flammable. Oxidizes readily in air to form unstable peroxides that may explode spontaneously [Bretherick 1979. p.151-154, 164]. A mixture of liquid air and diethyl ether exploded spontaneously [MCA Case History 616. 1960].
Ethers, such as tert-Butyl methyl ether, can act as bases. They form salts with strong acids and addition complexes with Lewis acids. The complex between diethyl ether and boron trifluoride is an example. Ethers may react violently with strong oxidizing agents. In other reactions, which typically involve the breaking of the carbon-oxygen bond, ethers are relatively inert.
Slightly toxic by ingestion and inhalation. Flammable when exposed to heat or flame. Upper respiratory tract irritant and kidney damage. Questionable carcinogen.
INHALATION: May cause dizziness or suffocation. Contact may irritate or burn eyes or skin. May be harmful if swallowed.
Methyl tert-butyl ether (MTBE) is used as an octane enhancer in gasoline. EPA regulations allow up to 2.7 wt.% oxygen in gasoline which allows 15 vol.% MTBE in gasoline. Other alkyl ethers can also be blended into gasoline up to the 2.7 wt% oxygen requirement. The stability of MTBE to oxidation and peroxide formation gives this unsymmetrical ether an advantage over other ethers in various extraction and reaction solvent applications.
Poison by intravenous route. Slightly toxic by ingestion and inhalation. Flammable when exposed to heat or flame. When heated to decomposition it emits acrid smoke and irritating fumes. See also ETHERS.
Used as an organic solvent; as an octane booster in unleaded gasolines; in making other chemicals; and in medicine to dissolve gall stones
Basis of determination of carcinogenicity of
chemical compounds. There is general agreement among
experts in chemical carcinogenesis that a substance that
causes cancer in significant numbers of experimental animals in well-conducted assays poses a presumptive carcinogenic
risk to humans, even in the absence of confirmatory epidemiological
data. This principle is accepted by scientific
and medical experts throughout the world and has served
for many years as the basis for sound public health policy
and regulatory action on carcinogens. For example, the
International Agency for Research on Cancer (IARC) of
the World Health Organization in its Supplement 7 of the
Ntp criteria for listing chemicals as “reasonably anticipated to be a human carcinogen”.
Evidence of MTBE as a potential human carcinogen. Evidence from three separate animal bioassay studies (two different species of rats and in mice) demonstrates that chronic exposure to MTBE by either oral or inhalation route of exposure causes cancers in animals.
tert-Butyl Methyl Ether can be released during manufacturing or blending with gasoline; during the storage, distribution, and transfer of MTBE-blended gasoline; and from spills or leaks or fugitive emissions at automotive service stations (U.S. EPA, 1994a). Vapor emissions from MTBE-blended gasoline may also contribute to atmospheric levels (U.S. EPA, 1988). It is not expected to persist in the atmosphere because it undergoes destruction from reactions with hydroxyl radicals. A total atmospheric lifetime for MTBE of approximately 3 and 6.1 days has been reported in polluted urban air and in nonpolluted rural air, respectively (U.S. EPA, 1993a). Based upon its vapor pressure and Henry s law constant, MTBE is highly volatile and would be expected to evaporate rapidly from soil surfaces or water. It may be fairly persistent when introduced into subsurface soils or to groundwater since volatilization to the atmosphere is reduced or eliminated. It does not readily degrade in surface waters due to hydrolysis or other abiotic processes. It is also resistant to biodegradation (U.S. EPA, 1993a). It is usually removed from surface waters very rapidly because of its high volatility. If released as part of a gasoline mixture from leaking underground storage tanks, its relatively high water solubility combined with little tendency to sorb to soil particles encourages migration to local groundwater supplies (U.S. EPA, 1993a).
UN2398 Methyl tert-butyl ether, Hazard Class: 3; Labels: 3-Flammable liquid.
Purify as for n-butyl methyl ether. [Beilstein 1 IV 1615.]
May form explosive mixture with air. May be able to form unstable peroxides. Much less likely to form peroxides than other ethers. Incompatible with strong acids. Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides. May accumulate static electrical charges, and cause ignition of its vapors.
Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed.
tert-Butyl methyl ether Preparation Products And Raw materials
- Isopropyl ether
- Isopropyl alcohol
- Bensulfuron methyl
- TERT-AMYL METHYL ETHER
- tert-Butyl ethyl ether
- METHYL N-PROPYL ETHER
- Methyl bromide
- tert-Butyl peroxyacetate
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