| Bromoethane | |
|---|---|
 |
 |
| Other names | Ethyl bromide |
| Identifiers | |
| CAS number | 74-96-4  |
| RTECS number | KH6475000 |
| SMILES |
CCBr
|
| Properties | |
| Molecular formula | C2H5Br |
| Molar mass | 108.97 g mol−1 |
| Appearance | Colorless liquid |
| Density | 1.47 g/mL |
| Melting point |
-119 °C, 154 K, -182 °F |
| Boiling point |
38.4 °C, 312 K, 101 °F |
| Solubility in water | 0.91 g/100 mL (20 °C) |
| Viscosity | 0.402 cP at 20 °C |
| Hazards | |
| EU classification | Flammable (F) Carc. Cat. 3 Harmful (Xn) |
| R-phrases | R11 R20/22 R40 |
| S-phrases | (S2) S36/37 |
| NFPA 704 |
 1
2
0
|
| Flash point | −20 °C |
| Autoignition temperature |
511 °C |
| Explosive limits | 6.8–11% |
| Related compounds | |
| Related haloalkanes | bromomethane Chloroethane Iodoethane |
| (what is this?) (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
|
| Infobox references | |
Bromoethane, also known as ethyl bromide, is a chemical compound of the haloalkanes group. It is abbreviated by chemists as EtBr. This volatile compound has an ether-like odour.
Contents |
Preparation
The preparation of EtBr stands as a model for the synthesis of alkyl bromides in general. It is usually prepared by the addition of HBr to ethylene:
- H2C=CH2 + HBr → H3C-CH2Br
Ethyl bromide is inexpensive and would rarely be prepared in the laboratory. A laboratory synthesis include the 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.[1]
Uses
In organic synthesis, EtBr is the synthetic equivalent of the ethyl carbocation (Et+) synthon.[2] In reality, such a cation is not actually formed. For example, carboxylates salts are converted to ethyl esters,[3] carbanions to ethylated derivatives, thiourea into ethylisothiouronium salts,[4] and amines into ethylamines.[5]
Safety
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
- ^ Oliver Kamm and C. S. Marvel (1941), "Alkyl and alkylene bromides", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0025; Coll. Vol. 1: 25
- ^ Makosza, M.; Jonczyk, A., "Phase-Transfer Alkylation of Nitriles: 2-Phenylbutyronitrile", Org. Synth. 55: 91, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv6p0897; Coll. Vol. 6: 897
- ^ Petit, Y.; Larchevêque, M., "Ethyl Glycidate from (S)-Serine: Ethyl (R)-(+)-2,3-Epoxypropanoate", Org. Synth. 75: 37, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=v75p0037; Coll. Vol. 10: 401
- ^ E. Brand, E.; Brand, F. C., "Guanidodacetic Acid", Org. Synth. 22: 440, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv3p0440; Coll. Vol. 3
- ^ Brasen, W. R; Hauser, C. R., "o-Methylethylbenzyl Alcohol", Org. Synth. 34: 58, http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv4p0582; Coll. Vol. 4: 582
External links
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