Bromoethane

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Bromoethane
Skeletal formula of bromoethane
Skeletal formula of bromoethane with all explicit hydrogens added
Ball and stick model of bromoethane
Spacefill model of bromoethane
Names
IUPAC name
Bromoethane[2]
Other names
Ethyl bromide[1]
Monobromoethane[1]
Identifiers
3D model (Jmol)
1209224
ChemSpider
ECHA InfoCard 100.000.751
EC Number 200-825-8
KEGG
MeSH bromoethane
RTECS number KH6475000
UN number 1891
Properties
C2H5Br
Molar mass 108.97 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)
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 pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark 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)
GHS signal word DANGER
H225, H302, H332, H351
P210, P281
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform 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 −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]
US health exposure limits (NIOSH):
PEL (Permissible)
TWA 200 ppm (890 mg/m3)[1]
REL (Recommended)
None established[1]
IDLH (Immediate danger)
2000 ppm[1]
Related compounds
Related alkanes
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

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 odour.

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 HBr 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]

Halocarbons in general are potentially dangerous alkylating agents. Bromides are better alkylating agents than chlorides, thus exposure to EtBr should be minimized. EtBr is classified by the State of California as carcinogenic and a reproductive toxin.

References[edit]

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

External links[edit]