1,2-Dibromoethane
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| Names | |||
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| IUPAC name
1,2-dibromoethane
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| Other names
ethylene dibromide
ethylene bromide EDB glycol bromide ethylene bromide, Bromofume (trade name), Dowfume (trade name) | |||
| Identifiers | |||
3D model (JSmol)
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| ChemSpider | |||
| ECHA InfoCard | 100.003.132 | ||
| RTECS number |
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CompTox Dashboard (EPA)
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| Properties | |||
| C2H4Br2 | |||
| Molar mass | 187.86 g/mol | ||
| Appearance | colorless liquid | ||
| Density | 2.17 g/cm³, liquid | ||
| Melting point | 9-10 °C | ||
| Boiling point | 131-132 °C | ||
| 1 part in 250 | |||
| Hazards | |||
| NFPA 704 (fire diamond) | |||
| Flash point | >104 °C | ||
| Related compounds | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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1,2-Dibromoethane, also known as ethylene dibromide (EDB), is the chemical compound with the formula BrCH2CH2Br. Although trace amounts occurs naturally in the ocean, where it is formed probably by algae and kelp, it is mainly a synthetic. This a colorless liquid with a sweet odor, detectable at 10 ppm, is a widely used and sometimes controversial fumigant.
Preparation and structure
It is manufactured by the reaction of ethylene with bromine, in a classic halogen addition reaction:
- CH2=CH2 + Br2 → BrCH2CH2Br
Uses
The once dominant use, although one that has faded, is as an additive in leaded gasoline. 1,2-Dibromoethane reacts with lead residues to generate volatile lead bromides. It has been used as a pesticide in soil, and various crops. The applications were initiated after the forced retirement of 1,2-dibromo-3-chloropropane (DBCP). Most of these uses have been stopped by in the U.S. It continues to be used a fumigant for treatment of logs for termites and beetles, control of moths in beehives, and as a preparation for dyes and waxes.[1]
1,2-Dibromoethane is used in organic synthesis as a source of bromine, e.g. to brominate carbanions and to activate magnesium for certain Grignard reagents. In the latter process, the 1,2-dibromoethane is converted to ethylene and magnesium bromide, exposing a freshly etched portion of magnesium to the substrate.[2]
Health effects
The effects on people of breathing high levels are not known, but animal studies with short-term exposures to high levels caused depression and collapse, indicating effects on the brain.[3]
Redness and inflammation, including skin blisters and mouth and stomach ulcers, can occur if large amounts are swallowed. One accidental swallowing caused death in a woman in Molokai, Hawaii[1][who?]. It is highly unlikely that there would be a risk of death to people from low-level exposure.
Although very little is known about the effects from breathing 1,2-dibromoethane over a long period of time, some male workers had reproductive effects including damage to their sperm.
In rats, death occurred from breathing high levels for a short time. Lower levels caused liver and kidney damage. When rats breathed air or ate food containing 1,2-dibromoethane for short or long periods of time, they were less fertile or had abnormal sperm.
Changes in the brain and behavior were also seen in young rats whose male parents had breathed 1,2-dibromoethane, and birth defects were observed in the young of animals that were exposed while pregnant. 1,2-Dibromoethane is not known to cause birth defects in humans.[3]
It is a known carcinogen, ranking as the top carcinogenic substance on the HERP Index.[4]
References
- ^ a b "Toxicalogical Profile for 1,2-Dibromoethane" (PDF). Retrieved 2009-11-22. Cite error: The named reference "www.atsdr.cdc.gov" was defined multiple times with different content (see the help page).
- ^ Maynard, G. D. "1,2-Dibromoethane" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. DOI: 10.1002/047084289.
- ^ a b "ToxFAQs for 1,2-Dibromoethane". Retrieved 2007-02-20.
- ^ "Ranking Possible Cancer Hazards on the HERP Index" (PDF). Retrieved 2010-10-14.