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
RTECS number	KH9275000
SMILES	C(Br)CBr
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 (what is this?)  (verify) 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 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^[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]

References

1. ^ ^{a b} "Toxicalogical Profile for 1,2-Dibromoethane". http://www.atsdr.cdc.gov/toxprofiles/tp37.pdf. Retrieved 2009-11-22. 
2. ^ 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.
3. ^ ^{a b} "ToxFAQs for 1,2-Dibromoethane". http://www.atsdr.cdc.gov/tfacts37.html. Retrieved 2007-02-20. 

External links

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