Bromoethane

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Bromoethane
Skeletal formula of bromoethane Bromoethane.png
Skeletal formula of bromoethane
Skeletal formula of bromoethane with all explicit hydrogens added Bromethan.svg
Skeletal formula of bromoethane with all explicit hydrogens added
Ball and stick model of bromoethane Bromoethane-3D-balls.png
Ball and stick model of bromoethane
Spacefill model of bromoethane Bromoethane-3D-vdW.png
Spacefill model of bromoethane
Names
Preferred IUPAC name
Bromoethane [1]
Other names
Ethyl bromide [2]
Monobromoethane [2]
Identifiers
3D model (JSmol)
1209224
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.751 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 200-825-8
KEGG
MeSH bromoethane
PubChem CID
RTECS number
  • KH6475000
UNII
UN number 1891
  • InChI=1S/C2H5Br/c1-2-3/h2H2,1H3 Yes check.svgY
    Key: RDHPKYGYEGBMSE-UHFFFAOYSA-N Yes check.svgY
  • CCBr
Properties
C2H5Br
Molar mass 108.966 g·mol−1
AppearanceColorless liquid
Odor ether-like
Density 1.46 g mL−1
Melting point −120 to −116 °C; −184 to −177 °F; 153 to 157 K
Boiling point 38.0 to 38.8 °C; 100.3 to 101.8 °F; 311.1 to 311.9 K
1.067 g/100 mL (0 °C)
0.914 g/100 mL (20 °C)
0.896 g/100 mL (30 °C)
Solubility miscible with ethanol, ether, chloroform, organic solvents
log P 1.809
Vapor pressure 51.97 kPa (at 20 °C)
1.3 μmol Pa−1 kg−1
−54.70·10−6 cm3/mol
1.4225
Viscosity 402 Pa.s (at 20 °C)
Thermochemistry
105.8 J K−1 mol−1
−97.6–93.4 kJ mol−1
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-skull.svg GHS-pictogram-silhouette.svg
Danger
H225, H302, H332, H351
P210, P281
NFPA 704 (fire diamond)
NFPA 704.svgHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
1
0
Flash point −23 °C (−9 °F; 250 K)
511 °C (952 °F; 784 K)
Explosive limits 6.75–11.25%
Lethal dose or concentration (LD, LC):
1.35 g kg−1(oral, rat)
26,980 ppm (rat, 1 hr)
16,230 ppm (mouse, 1 hr)
4681 ppm (rat)
2723 ppm (mouse) [3]
3500 ppm (mouse)
24,000 ppm (guinea pig, 30 min)
7000 ppm (guinea pig, >4.5 hr) [3]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 200 ppm (890 mg/m3) [2]
REL (Recommended)
None established [2]
IDLH (Immediate danger)
2000 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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Bromoethane, also known as ethyl bromide, is a chemical compound of the haloalkanes group. It is abbreviated by chemists as EtBr (which is also used as an abbreviation for ethidium bromide). This volatile compound has an ether-like odor.

Contents

Preparation

The preparation of EtBr stands as a model for the synthesis of bromoalkanes in general. It is usually prepared by the addition of hydrogen bromide to ethene:

H2C=CH2 + HBr → H3C-CH2Br

Bromoethane is inexpensive and would rarely be prepared in the laboratory. A laboratory synthesis includes reacting ethanol with a mixture of hydrobromic and sulfuric acids. An alternate route involves refluxing ethanol with phosphorus and bromine; phosphorus tribromide is generated in situ. [4]

Uses

In organic synthesis, EtBr is the synthetic equivalent of the ethyl carbocation (Et+) synthon. [5] In reality, such a cation is not actually formed. For example, carboxylates salts are converted to ethyl esters, [6] carbanions to ethylated derivatives, thiourea into ethylisothiouronium salts, [7] and amines into ethylamines. [8]

Safety

Short chain monohalocarbons in general are potentially dangerous alkylating agents. Bromides are better alkylating agents than chlorides, thus exposure to them should be minimized.

References

  1. ↑ "bromoethane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification. Retrieved 15 June 2012.
  2. 1 2 3 4 5 NIOSH Pocket Guide to Chemical Hazards. "#0265". National Institute for Occupational Safety and Health (NIOSH).
  3. 1 2 "Ethyl bromide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ↑ Oliver Kamm & C. S. Marvel (1941). "Alkyl and alkylene bromides". Organic Syntheses ; Collected Volumes, vol. 1, p. 25.
  5. ↑ Makosza, M.; Jonczyk, A. "Phase-Transfer Alkylation of Nitriles: 2-Phenylbutyronitrile". Organic Syntheses . 55: 91; Collected Volumes, vol. 6, p. 897.
  6. ↑ Petit, Y.; Larchevêque, M. "Ethyl Glycidate from (S)-Serine: Ethyl (R)-(+)-2,3-Epoxypropanoate". Organic Syntheses . 75: 37; Collected Volumes, vol. 10, p. 401.
  7. ↑ E. Brand; Brand, F. C. "Guanidodacetic Acid". Organic Syntheses . 22: 440; Collected Volumes, vol. 3.
  8. ↑ Brasen, W. R; Hauser, C. R. "o-Methylethylbenzyl Alcohol". Organic Syntheses . 34: 58; Collected Volumes, vol. 4, p. 582.
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