1,2-Dibromoethane

1,2-Dibromoethane
IUPAC name 1,2-dibromoethane
Other names ethylene dibromide ethylene bromide EDB glycol bromide ethylene bromide, Bromofume (trade name), Dowfume (trade name)
Identifiers
CAS number	106-93-4 Y
ChemSpider	7551 Y
KEGG	C11088 Y
ChEBI	CHEBI:28534 Y
ChEMBL	CHEMBL452370 Y
RTECS number	KH9275000
Jmol-3D images	Image 1
SMILES BrCCBr
InChI InChI=1S/C2H4Br2/c3-1-2-4/h1-2H2 Y Key: PAAZPARNPHGIKF-UHFFFAOYSA-N Y InChI=1/C2H4Br2/c3-1-2-4/h1-2H2 Key: PAAZPARNPHGIKF-UHFFFAOYAZ
Properties
Molecular formula	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
Solubility in water	1 part in 250
Hazards
R-phrases	R45, R23/24/25, R36/37/38, R51/53
S-phrases	S53, S45, S61
NFPA 704	0 3 0
Flash point	>104 °C
Related compounds
Related organobromides	bromoethane 1,1-Dibromoethane
Related compounds	1,2-dichloroethane
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

1,2-Dibromoethane, also known as ethylene dibromide (EDB), is the organobromine compound with the chemical formula (CH₂Br)₂. Although trace amounts occur naturally in the ocean, where it is formed probably by algae and kelp, it is mainly synthetic. It is a colorless liquid with a sweet odor, detectable at 10 ppm, is a widely used and sometimes-controversial fumigant.^[1]

Preparation and structure

It is produced by the reaction of ethylene with bromine, in a classic halogen addition reaction:

CH₂=CH₂ + Br₂ → BrCH₂CH₂Br

Uses

Gasoline additive

Historically, 1,2-dibromoethane was used as an anti-knock additive in leaded fuels. It reacts with lead residues to generate volatile lead bromides, thereby preventing fouling of the engine by lead oxides.^[2]

Pesticide

It has been used as a pesticide in soil and on various crops. The applications were initiated after the forced retirement of 1,2-dibromo-3-chloropropane (DBCP).^[1] Most of these uses have been stopped in the U.S. It continues to be used as a fumigant for treatment of logs for termites and beetles, for control of moths in beehives.^[3]

Reagent in organic synthesis

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.^[4]

Ethylene bromide has wider applications in the preparation of other organic compounds. It is used to make vinyl bromide, a precursor to some fire retardants.^[1]

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. 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.^[5] Swallowing has caused death at 40 mL doses^[3]

It is a known carcinogen, with pre-1977 exposure levels ranking it as the most carcinogenic substance on the HERP Index.^[6]

References

1. ^ ^{a b c} Michael J. Dagani, Henry J. Barda, Theodore J. Benya, David C. Sanders "Bromine Compounds" in Ullmann's Encyclopedia of Industrial Chemistry" Wiley-VCH, Weinheim, 2000.doi:10.1002/14356007.a04_405
2. ^ Seyferth, D. (2003). "The Rise and Fall of Tetraethyllead. 2". Organometallics 22: 5154–5178. doi:10.1021/om030621b. 
3. ^ ^{a b} "Toxicalogical Profile for 1,2-Dibromoethane". Archived from the original on 22 November 2009. http://web.archive.org/web/20091122182238/http://www.atsdr.cdc.gov/toxprofiles/tp37.pdf. Retrieved 2009-11-22. 
4. ^ 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.
5. ^ http://www.atsdr.cdc.gov/mmg/mmg.asp?id=1062&tid=131
6. ^ "Ranking Possible Cancer Hazards on the HERP Index". http://potency.lbl.gov/pdfs/herp.pdf. Retrieved 2010-10-14. 

External links

• National Pollutant Inventory 1,2-Dibromoethane Fact Sheet
• Congressional Research Service (CRS) Reports regarding Ethylene Dibromide
• ATSDR ToxFAQs