Bromoethane
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| Names | |||
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| Preferred IUPAC name
Bromoethane[2] | |||
| Other names | |||
| Identifiers | |||
3D model (JSmol)
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| 1209224 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| ECHA InfoCard | 100.000.751 | ||
| EC Number |
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| KEGG | |||
| MeSH | bromoethane | ||
PubChem CID
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| RTECS number |
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| UNII | |||
| UN number | 1891 | ||
CompTox Dashboard (EPA)
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| Properties | |||
| C2H5Br | |||
| Molar mass | 108.966 g·mol−1 | ||
| Appearance | Colorless 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) | ||
Henry's law
constant (kH) |
1.3 μmol Pa−1 kg−1 | ||
| -54.70·10−6 cm3/mol | |||
Refractive index (nD)
|
1.4225 | ||
| Viscosity | 402 Pa.s (at 20 °C) | ||
| Thermochemistry | |||
Heat capacity (C)
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105.8 J K−1 mol−1 | ||
Std enthalpy of
formation (ΔfH⦵298) |
−97.6–93.4 kJ mol−1 | ||
| Hazards | |||
| GHS labelling: | |||
  
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| Danger | |||
| H225, H302, H332, H351 | |||
| P210, P281 | |||
| NFPA 704 (fire diamond) | |||
| 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): | |||
LD50 (median dose)
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1.35 g kg−1 (oral, rat) | ||
LC50 (median concentration)
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26,980 ppm (rat, 1 hr) 16,230 ppm (mouse, 1 hr) 4681 ppm (rat) 2723 ppm (mouse)[3] | ||
LCLo (lowest published)
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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)
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TWA 200 ppm (890 mg/m3)[1] | ||
REL (Recommended)
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None established[1] | ||
IDLH (Immediate danger)
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2000 ppm[1] | ||
| 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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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.
Preparation
[edit]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
[edit]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
[edit]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
[edit]- ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0265". National Institute for Occupational Safety and Health (NIOSH).
- ^ "bromoethane - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification. Retrieved 15 June 2012.
- ^ a b "Ethyl bromide". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^ Oliver Kamm & C. S. Marvel (1941). "Alkyl and alkylene bromides". Organic Syntheses; Collected Volumes, vol. 1, p. 25.
- ^ Makosza, M.; Jonczyk, A. "Phase-Transfer Alkylation of Nitriles: 2-Phenylbutyronitrile". Organic Syntheses. 55: 91; Collected Volumes, vol. 6, p. 897.
- ^ Petit, Y.; Larchevêque, M. "Ethyl Glycidate from (S)-Serine: Ethyl (R)-(+)-2,3-Epoxypropanoate". Organic Syntheses. 75: 37; Collected Volumes, vol. 10, p. 401.
- ^ E. Brand; Brand, F. C. "Guanidodacetic Acid". Organic Syntheses. 22: 440; Collected Volumes, vol. 3.
- ^ Brasen, W. R; Hauser, C. R. "o-Methylethylbenzyl Alcohol". Organic Syntheses. 34: 58; Collected Volumes, vol. 4, p. 582.