Methyl tert-butyl ether
| Methyl tert-butyl ether | |
|---|---|
| |
| General | |
| Other names |
Methyl tertiary-butyl ether |
| Molecular formula | C5H12O |
| SMILES | CC(C)(C)OC |
| Molar mass | Molar mass::88.15 g/mol |
| Appearance | Colorless liquid |
| CAS number | CAS number::1634-04-4 |
| Properties | |
| Density and phase | Density::0.7404 g/cm³ |
| Solubility in water | g/100 ml (20°C) |
| Melting point | Melting point::-109°C |
| Boiling point | Boiling point::55.2°C |
| MSDS | Material Safety Data Sheet |
| Main hazards | Flammable |
| NFPA 704 |
3
2
0
|
| Flash point | -10°C |
| RTECS number | KN4730200 |
| Related compounds | |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Disclaimer and references | |
Methyl tert-butyl ether is a flammable liquid with a distinctive, unpleasant odor. It was made in the 80's by blending isobutylene and methanol and other assorted chemicals and it is used as an additive in gasoline. MTBE is not used as much as it has previously has been for it has been detected in 10% of the U.S. drinking water. Since it is hazards' by direct smell, contact or indigestion some states have recently banned MTBE.[1]
Properties
MTBE is a colorless liquid with a vapor pressure of 245 mm Hg at 25 °C at STP but has a distinctive anesthetic-like odor. Its molecular formula is CH3OC(CH3)3. It is highly flammable at temperatures between 28°C and 30°C. Oxidizes readily in air to form unstable peroxides that may explode spontaneously. In most cases of a fire with MTBE it normally could not be put out with one fire hose since it has the capability to blend with water so it must be drenched with streams of water to put it out.[2]
MTBE is also called tert-butyl methyl ether. It has a log octanol/water partition coefficient (log Kow) of 1.24 and its molecular weight is 88.15 g/mol. At 52.6 °C with water it forms azeotropes and methanol 51.3 °C.[3]
Occurrences
Methyl tert-butyl ether is not a natural chemical. MTBE is made by blending chemicals like isobutylene(One of the four isomers of butene, which are hydrocarbons) and methanol(which is the simplest alcohols). MTBE was produced with almost 200,000 barrels per day. But since 2006 most states stopped the use of MTBE as an oxygenate for it seeps into groundwater. The only way it stays in its liquid form is when it mixes with ground water for when it is exposed to the atmosphere it immediately evaporates. Other wise it is completely harmless.[4]
Uses
Since 1979, MTBE was used as a gasoline additive in unleaded gasoline, since tetra-ethyl lead was more of an engine knocker MTBE helps and prevents this from happening. By upsurging the octane levels it decreases the carbon monoxide emissions in the engine. Years ago it was used to produce isobutene.[5] In medical practices it is use for a solvent in the dissolution in gallstones. Even the sewage industry uses MTBE for leachates.[6]But since 1999 some states drasticaly reduced the use of MTBE because it can seep down into the groundwater and contaminate it.
MTBE is used as a solvent for anything. It has replaced most ether for it has a much lower tendency to form explosive organic peroxides. Opened bottles of diethyl ether or THF can build up dangerous amounts of these types of peroxides within a few months. As MTBE is safer for years(for it has a much higher boiling point) it's mainly used as a solvent in industry but rarely in academia for it has a much lower cost than diethyl ether, THF, or other ethers. It is rarwly used as a solvent for literature synthetic procedures.[7]
Health Hazards
Exposure to MTBE are attributed to breathing exhaust fumes, exposure to gasoline, etc. Even in small amounts one may receive headaches, throat irritation, or mental confusion. MTBE has no evidence to cause cancer, but, on rats for a very long period of time, it is known to cause kidney damage. There is no test to determine if one has been exposed to MTBE but traces of butyl alcohol have known to be found in one's blood or breath after 1 to 2 days after exposure. Also the EPA has commented that to protect children it is recommended that drinking water levels of MTBE not exceed 4 milligrams per liter of water (4 mg/L).[8]
First Aid
If MTBE is to be in contact with any of the following:
Inhaled: Remove the source of contamination, send patient to get fresh air and immediately see a doctor certified in this type of incident.
Skin Contact: Wash with lukewarm water that is gently flowing for twenty minutes or until is it completely removed. Remove all contaminated clothing and seek medical help. If you wish dispose or reuse clothing you must first decontaminate the clothing.
Eye Contact: Rinse with gently flowing lukewarm water while holding eyelid open for five minutes or until chemical is removed.
Ingested: Do not supply indigestion treatment if patient is losing consciousness or is convulsing. Make the person rinse their mouth and make sure they Do not induce vomit have them drink 8 to 10 oz's of water. Then seek medical attention immediately.[9]
Environmental Risks
It is expected that MTBE is to break down when exposed to the air. When it is mixed with normal water instead of ground water it slowly dissolves but, if it does go to ground water it only mixes. Since 199 it is known that 5-10% of community drinking water was contaminated with MTBE. MTBE is considered to be a human carcinogen. [10]
References
- Agency for Research on Cancer
- Basic Info
- Technology Transfer Network Air Toxics Web Site
- ToxFAQs
- CHEMINFO
- All you need to know
- for Toxic Substances and Disease Registry
- protection
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