tert-Butyl ethyl ether

Description

In the 1990s, the production of other fuel oxygenates began, with the appearance of ethyl tertiary-butyl ether, CAS RN 637- 92-3 (ETBE), first produced in France in 1992, and tertiary-amyl methyl ether, CAS RN 994-05-8 (TAME). To their number others have been added, such as diisopropyl ether, CAS RN 108-20-3 (DIPE) and, most recently, tertiary-amyl ethyl ether, CAS RN 919-94-8 (TAEE), which is being produced in Germany; however, the use of these oxygenates is currently small scale. Alcohols, such as ethanol, CAS RN 64-17-5 (EtOH) and methanol, may also be used as fuel oxygenates, but methanol is not used as such, although it is used in China as a liquid fuel for passenger cars and for synthesis of dimethyl ether as an alternative to diesel fuel for trucks and buses. Ethers have the advantage over alcohols in currently designed engines because alcohols in petrol tend to make the blend very volatile and water soluble, possibly creating problems in the fueldistribution system and vehicle engine. Perhaps the larger-scale use of ethanol in fuel oxygenation is in the production of ETBE or coblending with ETBE.

Chemical properties

tert-Butyl ethyl ether is a colourless to light yellow liquid at a temperature range of -94 to 72.6 °C. It is soluble in ethanol, ethyl ether, and water. tert-Butyl ethyl ether has a strong, highly objectionable odor and taste at relatively low concentrations. This chemical is highly flammable and reacts with strong oxidizing agents. tert-Butyl ethyl ether is stable when stored at room temperature in tightly closed containers.

The Uses of tert-Butyl ethyl ether

Gasoline additive. tert-Butyl ethyl ether is synthesized from ethanol and isobutene and is used primarily as an oxygenate that is added to gasoline to improve the automobile exhaust quality by reducing the ozone and carbon monoxide emissions (HSDB, 2012). tert-Butyl ethyl ether has similar utility compared to another widely used oxygenate, methyl tertiary butyl ether (MTBE), and thus is a potential replacement for MTBE.Usage of ETBE as a fuel additive has halted in the United States, falling from 2 to 4 million barrels per month in 2005 to 0 barrels in 2006 (DOE, 2007). tert-Butyl ethyl ether continues to be used widely in Europe (EFOA, 2010). Since ETBE is used almost exclusively in fuels, contamination of groundwater as a result of spillage or leakage of the underground storage tanks is a major source of environmental release.

The Uses of tert-Butyl ethyl ether

In 2006, because of litigation and liability fears, the blending (but not the production) of MTBE into petrol in the United States was discontinued, whereas the European Union (EU) has continued its use of ethers in blending. Other global producers and consumers of fuel ether oxygenates are the Middle East, South America (excluding Brazil), Mexico, and a large portion of Asia. The current global production capacity is estimated to be approximately 18 Mton year1. The expected demand for MTBE t ETBE in Asia is 11.9 Mton. In 2010, China was the world’s largest producer of MTBE (6.8 Mton year1), yet was also importing MTBE at 740 kton in the same year. In Japan, Bio-ETBE is the biofuel of choice for petrol. It is preferred over alcohols in Japan on the basis of emission benefits, vehicle performance, and existing regulations.

The Uses of tert-Butyl ethyl ether

tert-Butyl ethyl ether is used as an oxygenate gasoline additive oxygenate during its production from crude oil. It is used as an extractant in human urine by using single-walled carbon nanotubes as an adsorbent. It plays an important role as a fuel component in petrol to enhance its octane rating.

Definition

ChEBI: Tert-butyl ethyl ether is an ether having ethyl and tert-butyl as the two alkyl components. It is used as an engine fuel additive to reduce emissions of carbon monoxide and soot. It has a role as a fuel additive. It is an ether and a volatile organic compound.

Synthesis Reference(s)

Tetrahedron Letters, 29, p. 2445, 1988 DOI: 10.1016/S0040-4039(00)87903-4

General Description

Clear light yellow liquid.

Air & Water Reactions

Highly flammable. TERT-BUTYL ETHYL ETHER may react with air to form dangerous peroxides. . Insoluble in water.

Reactivity Profile

TERT-BUTYL ETHYL ETHER can act as a base to form salts with strong acids and addition complexes with Lewis acids. May react violently with strong oxidizing agents. Relatively inert in other reactions, which typically involve the breaking of the carbon-oxygen bond.

Health Hazard

Inhalation or contact with material may irritate or burn skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution.

Fire Hazard

TERT-BUTYL ETHYL ETHER is flammable.

Flammability and Explosibility

Highly flammable

Environmental Fate

Due to the usage of Ethyl tertiary butyl ether (ETBE ) as a fuel additive, ETBE may be released into air, soil, and water. Ethyl tertiary butyl ether will exist as a vapor at 25 °C due to its vapor pressure of 124mmHg and is estimated to have a half-life of 2 days. Upon release into the soil, ETBE is anticipated to have a high mobility based on the high soil organic carbon–water partitioning coefficient of 9–160. Once in the water, ETBE is not predicted to adsorb onto suspended particles and is likely to resist biodegradation (Deeb et al., 2001). Based on the Henry’s law constant, ETBE is likely to be volatized from the surface of the water (HSDB, 2012). A volatilization halflife of 3 h to 4 days is anticipated from water solutions. A bioconcentration factor (BCF) of 9 was estimated for ETBE to accumulate in fish, suggesting a relatively low propensity for aquatic bioaccumulation (HSDB, 2012).

Purification Methods

Dry the ether with CaSO4, pass it through an alumina column, and fractionally distil it. [Beilstein 1 IV 1618.]