1,2-Dibromoethane
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Names | |||
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IUPAC name
1,2-Dibromoethane[1]
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Other names | |||
Identifiers | |||
3D model (JSmol)
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Abbreviations | EDB[citation needed] | ||
605266 | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.003.132 | ||
EC Number |
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KEGG | |||
MeSH | Ethylene+Dibromide | ||
PubChem CID
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RTECS number |
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UNII | |||
UN number | 1605 | ||
CompTox Dashboard (EPA)
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Properties | |||
C2H4Br2 | |||
Molar mass | 187.862 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 | ||
Henry's law
constant (kH) |
14 μmol Pa kg−1 | ||
Refractive index (nD)
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1.539 | ||
Thermochemistry | |||
Heat capacity (C)
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134.7 J K−1 mol−1 | ||
Std molar
entropy (S⦵298) |
223.30 J K−1 mol−1 | ||
Std enthalpy of
combustion (ΔcH⦵298) |
−1.2419–−1.2387 MJ mol−1 | ||
Hazards | |||
Occupational safety and health (OHS/OSH): | |||
Main hazards
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carcinogen[2] | ||
GHS labelling: | |||
Danger | |||
H301, H311, H315, H319, H331, H335, H350, H411 | |||
P261, P273, P280, P301+P310, P305+P351+P338 | |||
NFPA 704 (fire diamond) | |||
Flash point | > 104 °C (219 °F; 377 K) | ||
Lethal dose or concentration (LD, LC): | |||
LD50 (median dose)
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LC50 (median concentration)
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1831 ppm (rat, 30 min) 691 ppm (rat, 1 hr)[3] | ||
LCLo (lowest published)
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200 ppm (rat, 8 hr) 400 ppm (guinea pig, 3 hr)[3] | ||
NIOSH (US health exposure limits): | |||
PEL (Permissible)
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TWA 20 ppm C 30 ppm 50 ppm [5-minute maximum peak][2] | ||
REL (Recommended)
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Ca TWA 0.045 ppm C 0.13 ppm [15-minute][2] | ||
IDLH (Immediate danger)
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Ca [100 ppm][2] | ||
Related compounds | |||
Related alkanes
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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 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
- ^ a b "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 657. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
- ^ a b c d e f g h NIOSH Pocket Guide to Chemical Hazards. "#0270". National Institute for Occupational Safety and Health (NIOSH).
- ^ a b "Ethylene dibromide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^ a b c Dagani, M. J.; Barda, H. J.; Benya, T. J.; Sanders, D. C. "Bromine Compounds". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a04_405. ISBN 978-3527306732.
- ^ Seyferth, D. (2003). "The Rise and Fall of Tetraethyllead. 2". Organometallics. 22 (25): 5154–5178. doi:10.1021/om030621b.
- ^ a b "Toxicological Profile for 1,2-Dibromoethane" (PDF). Archived from the original (PDF) on 2009-11-22. Retrieved 2009-11-22.
- ^ Maynard, G. D. (2004). "1,2-Dibromoethane". In L. Paquette (ed.). Encyclopedia of Reagents for Organic Synthesis. New York: J. Wiley & Sons. doi:10.1002/047084289 (inactive 2018-08-27).
{{cite encyclopedia}}
: CS1 maint: DOI inactive as of August 2018 (link) - ^ http://www.atsdr.cdc.gov/mmg/mmg.asp?id=1062&tid=131
- ^ "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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