1,2-Dibromoethane

1,2-Dibromoethane
Names
IUPAC name
1,2-Dibromoethane[1]
Other names
  • Ethylene dibromide[1]
  • Ethylene bromide[2]
  • Glycol bromide[2]
Identifiers
3D model (JSmol)
Abbreviations EDB
605266
ChEBI
ChemSpider
ECHA InfoCard 100.003.132
EC Number 203-444-5
KEGG
MeSH Ethylene+Dibromide
RTECS number KH9275000
UNII
UN number 1605
Properties
C2H4Br2
Molar mass 187.86 g·mol−1
Appearance Colorless liquid
Odor sweet[2]
Density 2.18 g mL−1
Melting point 9.4 to 10.2 °C; 48.8 to 50.3 °F; 282.5 to 283.3 K
Boiling point 129 to 133 °C; 264 to 271 °F; 402 to 406 K
0.4% (20 °C)[2]
log P 2.024
Vapor pressure 1.56 kPa
14 μmol Pa kg−1
1.539
Thermochemistry
134.7 J K−1 mol−1
223.30 J K−1 mol−1
−1.2419–−1.2387 MJ mol−1
Hazards
Main hazards carcinogen[2]
GHS pictograms
GHS signal word DANGER
H301, H311, H315, H319, H331, H335, H350, H411
P261, P273, P280, P301+310, P305+351+338
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
0
3
0
Flash point > 104 °C (219 °F; 377 K)
Lethal dose or concentration (LD, LC):
  • 55.0 mg kg−1 (oral, rabbit)
  • 79.0 mg kg−1 (oral, chicken)
  • 110.0 mg kg−1 (oral, guinea pig)
  • 130.0 mg kg−1 (oral, quail)
  • 300.0 mg kg−1 (dermal, rabbit)
1831 ppm (rat, 30 min)
691 ppm (rat, 1 hr)[3]
200 ppm (rat, 8 hr)
400 ppm (guinea pig, 3 hr)[3]
US health exposure limits (NIOSH):
PEL (Permissible)
 TWA 20 ppm C 30 ppm 50 ppm [5-minute maximum peak][2]
REL (Recommended)
 Ca TWA 0.045 ppm C 0.13 ppm [15-minute][2]
IDLH (Immediate danger)
 Ca [100 ppm][2]
Related compounds
Related alkanes
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.[4]

Preparation and use

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

CH2=CH2 + Br2 → BrCH2CH2Br

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.[5]

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).[4] 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.[6]

Reagent

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.[4]

In the laboratory, 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.[7]

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.[8] Swallowing has caused death at 40 mL doses[6]

It is a known carcinogen, with pre-1977 exposure levels ranking it as the most carcinogenic substance on the HERP Index.[9]

References

  1. 1 2 Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 657. ISBN 978-0-85404-182-4. doi:10.1039/9781849733069-FP001.
  2. 1 2 3 4 5 6 7 8 "NIOSH Pocket Guide to Chemical Hazards #0270". National Institute for Occupational Safety and Health (NIOSH).
  3. 1 2 "Ethylene dibromide". Immediately Dangerous to Life and Health. National Institute for Occupational Safety and Health (NIOSH).
  4. 1 2 3 Dagani, M. J.; Barda, H. J.; Benya, T. J.; Sanders, D. C. (2005), "Bromine Compounds", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a04_405
  5. ↑ Seyferth, D. (2003). "The Rise and Fall of Tetraethyllead. 2". Organometallics. 22 (25): 5154–5178. doi:10.1021/om030621b.
  6. 1 2 "Toxicological Profile for 1,2-Dibromoethane" (PDF). Archived from the original (PDF) on 2009-11-22. Retrieved 2009-11-22.
  7. ↑ Maynard, G. D. (2004). "1,2-Dibromoethane". In L. Paquette. Encyclopedia of Reagents for Organic Synthesis. New York: J. Wiley & Sons. doi:10.1002/047084289.
  8. ↑ http://www.atsdr.cdc.gov/mmg/mmg.asp?id=1062&tid=131
  9. ↑ "Ranking Possible Cancer Hazards on the HERP Index" (PDF). Archived from the original (PDF) on 2011-05-11. Retrieved 2010-10-14.
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