1,2-Dibromoethane

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1,2-Dibromoethane
Skeletal formula of 1,2-dibromoethane Skeletal formula of 1,2-dibromoethane with all explicit hydrogens added
Spacefill model of 1,2-dibromoethane
Identifiers
Abbreviations EDB[citation needed]
CAS number 106-93-4 YesY
PubChem 7839
ChemSpider 7551 YesY
EC number 203-444-5
UN number 1605
KEGG C11088 YesY
MeSH Ethylene+Dibromide
ChEBI CHEBI:28534 YesY
ChEMBL CHEMBL452370 YesY
RTECS number KH9275000
Beilstein Reference 605266
Jmol-3D images Image 1
Properties
Molecular formula C2H4Br2
Molar mass 187.86 g mol−1
Appearance Colorless liquid
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
log P 2.024
Vapor pressure 1.56 kPa
kH 14 μmol Pa kg−1
Refractive index (nD) 1.539
Thermochemistry
Specific
heat capacity
C
134.7 J K−1 mol−1
Std molar
entropy
So298
223.30 J K−1 mol−1
Std enthalpy of
combustion
ΔcHo298
−1.2419–−1.2387 MJ mol−1
Hazards
GHS pictograms The skull-and-crossbones pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The environment pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal word DANGER
GHS hazard statements H301, H311, H315, H319, H331, H335, H350, H411
GHS precautionary statements P261, P273, P280, P301+310, P305+351+338
EU Index 602-010-00-6
EU classification Toxic T Dangerous for the Environment (Nature) N
R-phrases R45, R23/24/25, R36/37/38, R51/53
S-phrases S45
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
Flash point >104 °C
LD50
  • 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)
Related compounds
Related alkanes
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
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.[2]

Preparation and use[edit]

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.[3]

Pesticide[edit]

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).[2] 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.[4]

Reagent[edit]

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.[2]

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.[5]

Health effects[edit]

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.[6] Swallowing has caused death at 40 mL doses[4]

It is a known carcinogen, with pre-1977 exposure levels ranking it as the most carcinogenic substance on the HERP Index.[7]

References[edit]

  1. ^ "Ethylene Dibromide - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 16 September 2004. Identification. Retrieved 19 June 2012. 
  2. ^ a b c 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 
  3. ^ Seyferth, D. (2003). "The Rise and Fall of Tetraethyllead. 2". Organometallics 22 (25): 5154–5178. doi:10.1021/om030621b. 
  4. ^ a b "Toxicological Profile for 1,2-Dibromoethane". Archived from the original on 2009-11-22. Retrieved 2009-11-22. 
  5. ^ 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. 
  6. ^ http://www.atsdr.cdc.gov/mmg/mmg.asp?id=1062&tid=131
  7. ^ "Ranking Possible Cancer Hazards on the HERP Index". Retrieved 2010-10-14. 

External links[edit]