From Wikipedia, the không tính phí encyclopedia
Bạn đang xem: etilen br2
|Preferred IUPAC name
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||187.862 g·mol−1|
|Density||2.18 g mL−1|
|Melting point||9.4 to tát 10.2 °C; 48.8 to tát 50.3 °F; 282.5 to tát 283.3 K|
|Boiling point||129 to tát 133 °C; 264 to tát 271 °F; 402 to tát 406 K|
Solubility in water
|0.4% (20 °C)|
|Vapor pressure||1.56 kPa|
|14 μmol Pa kg−1|
Refractive index (nD)
Heat capacity (C)
|134.7 J K−1 mol−1|
|223.30 J K−1 mol−1|
Std enthalpy of
|−1.2419–−1.2387 MJ mol−1|
|Occupational safety and health (OHS/OSH):|
Xem thêm: sinh tháng 1 là cung gì
|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)
LC50 (median concentration)
|1831 ppm (rat, 30 min)|
691 ppm (rat, 1 hr)
LCLo (lowest published)
|200 ppm (rat, 8 hr)|
400 ppm (guinea pig, 3 hr)
|NIOSH (US health exposure limits):|
|TWA đôi mươi ppm C 30 ppm 50 ppm [5-minute maximum peak]|
|Ca TWA 0.045 ppm C 0.13 ppm [15-minute]|
IDLH (Immediate danger)
|Ca [100 ppm]|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
verify (what is ?)
1,2-Dibromoethane, also known as ethylene dibromide (EDB), is an organobromine compound with the chemical formula C
2. Although trace amounts occur naturally in the ocean, where it is probably formed by algae and kelp, it is mainly synthetic. It is a dense colorless liquid with a faint, sweet odor, detectable at 10 ppm, and is a widely used and sometimes-controversial fumigant. The combustion of 1,2-dibromoethane produces hydrogen bromide gas that is significantly corrosive.
Preparation and use
It is produced by the reaction of ethylene gas with bromine, in a classic halogen addition reaction:
- CH2=CH2 + Br2 → BrCH2–CH2Br
Historically, 1,2-dibromoethane was used as a component in anti-knock additives in leaded fuels. It reacts with lead residues to tát generate volatile lead bromides, thereby preventing fouling of the engine with lead deposits.
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). Most of these uses have been stopped in the U.S. It continues to tát be used as a fumigant for treatment of logs for termites and beetles, and for control of moths in beehives.
1,2-Dibromoethane has wider applications in the preparation of other organic compounds including those carrying modified diazocine rings and vinyl bromide that is a precursor to tát some fire retardants.
In organic synthesis, 1,2-dibromoethane is used as a source of bromine to tát brominate carbanions and to tát activate magnesium for certain Grignard reagents. In the latter process, 1,2-dibromoethane reacts with magnesium, producing ethene and magnesium bromide, and exposes a freshly etched portion of magnesium to tát the substrate.
1,2-Dibromoethane causes changes in the metabolism and severe destruction of living tissues. The known empirical LD50 values for 1,2-dibromoethane are 140 mg kg−1 (oral, rat), and 300.0 mg kg−1 (dermal, rabbit). 1,2-Dibromoethane is a known carcinogen, with pre-1977 exposure levels ranking it as the most carcinogenic substance on the HERP Index.
The effects on people of breathing high levels are not known, but animal studies with short-term exposures to tát 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 tát cause birth defects in humans. Swallowing has caused death at 40ml doses.
Xem thêm: hai đứa trẻ thạch lam
- ^ a b "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. năm trước. 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 tát Chemical Hazards. "#0270". National Institute for Occupational Safety and Health (NIOSH).
- ^ a b "Ethylene dibromide". Immediately Dangerous to tát 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.
- ^ a b c "Safety Data Sheet for CAS-No.:106-93-4 Ethylene dibromide".
- ^ "Preparation and purification of 1,2-dibromoethane" (PDF). Synlett. 28: 49–51. 2017.
- ^ 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.
- ^ Hamada, Y.; Mukai. S. (1996). "Synthesis of ethano-Tröger's base, configurationally stable substitute of Tröger's base". Tetrahedron Asymmetry. 7 (9): 2671–2674. doi:10.1016/0957-4166(96)00343-6.
- ^ Maynard, G. D. (2004). "1,2-Dibromoethane". In Paquette, L. (ed.). Encyclopedia of Reagents for Organic Synthesis. New York: J. Wiley & Sons. doi:10.1002/047084289X.rd039. ISBN 0471936235.
- ^ "Ranking Possible Cancer Hazards from Rodent Carcinogens" (PDF). Archived from the original (PDF) on 2019-06-29.
- ^ "Toxic Substances Portal – 1,2-Dibromoethane".
- National Pollutant Inventory 1,2-Dibromoethane Fact Sheet
- Congressional Research Service (CRS) Reports regarding Ethylene Dibromide
- ATSDR ToxFAQs
- CDC – NIOSH Pocket Guide to tát Chemical Hazards