Diethyl ether
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| Diethyl ether | |
|---|---|
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| General | |
| Systematic name | ethoxyethane 3-oxapentane |
| Other names | diethyl ether ethyl ether ethyl oxide |
| Molecular formula | C4H10O C2H5OC2H5 |
| SMILES | CCOCC |
| Molar mass | 74.12 g/mol |
| Appearance | clear, colorless liquid |
| CAS number | [60-29-7] |
| Properties | |
| Density and phase | 0.7134 g/cm3, liquid |
| Solubility in water | 6.9 g/100 ml (20 °C) |
| Melting point | −116.3 °C (156.85 K) |
| Boiling point | 34.6 °C (307.75 K) |
| Acidity (pKa) | ? |
| Basicity (pKb) | ? |
| Viscosity | 0.224 cP at 25 °C |
| Structure | |
| Molecular shape | ? |
| Dipole moment | 1.15 D (gas) |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Extremely Flammable (F+), Irritant (Xi) |
| NFPA 704 |
4
2
1
|
| Flash point | -45 °C |
| Autoignition temperature |
170 °C |
| R/S statement | R12 R19 R22 R66 R67 S9 S16 S29 S33 |
| RTECS number | KI5775000 |
| Supplementary data page | |
| Structure and properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data | UV, IR, NMR, MS |
| Related compounds | |
| Related Ethers | Dimethyl ether Methoxypropane |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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- This article is about the chemical compound. For other uses, see aether.
Diethyl ether, also known as ether and ethoxyethane, is a clear, colorless, and highly flammable liquid with a low boiling point and a characteristic smell. Diethyl ether has the formula CH3-CH2-O-CH2-CH3. It is used as a common solvent and has been used as a general anesthetic. Diethyl ether has a high cetane number of 85 - 96 and is used as a starting fluid for diesel and gasoline engines. Ether is sparingly soluble in water (6.9 g/100 ml).
Contents |
[edit] History
Alchemist Raymundus Lullus is credited with discovering the compound in 1275, although there is no contemporary evidence of this. It was first synthesized in 1540 by Valerius Cordus, who called it "oil of sweet vitriol" (oleum dulci vitrioli)—the name was due to the fact that it was originally discovered by distilling a mixture of ethanol and sulfuric acid (then known as oil of vitriol)—and noted some of its medicinal properties. At about the same time, Theophrastus Bombastus von Hohenheim, better known as Paracelsus, discovered ether's analgesic properties. The name ether was given to the substance in 1730 by A.S.Frobenius.
[edit] Anesthetic use
The American doctor Crawford Williamson Long, M.D., was the first surgeon to use it as a general anesthetic, on March 30, 1842. William T.G. Morton is credited with the first public demonstration of ether anesthesia on October 16, 1846 at the Ether Dome in Boston, Massachusetts. The use of flammable ether waned as nonflammable anesthetic agents such as halothane became available.
Because of its high volatility, low ignition point, and tendency to form explosive peroxides, diethyl ether must be used with care in laboratory settings.
Ether may be used to anesthetize ticks before removing them from an animal or a person's body. The anesthesia relaxes the tick and prevents it from maintaining its mouthpart under the skin.
[edit] Recreational use
The anesthetic effects of ether have made it a recreational drug, although not a popular one. Diethyl ether is not as toxic as other solvents used as recreational drugs (see volatile substance abuse).
Ether, mixed with ethanol, was marketed in the 19th century as a cure-all and recreational drug, during one of Western society's temperance movements. At the time, it was considered improper for women to consume alcoholic beverages at social functions, and sometimes ether-containing drugs would be consumed instead. A cough medicine called Hoffmann's Drops was marketed at the time as one of these drugs, and contained both ether and alcohol in its capsules. [1] Ether tends to be difficult to consume alone, and thus was often mixed with drugs like ethanol for recreational use. Ethyl ether is listed as a Table II precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances[2].
Due to its immiscibility with water and the fact that non-polar organic compounds are highly soluble in it, ether is also used in the production of freebase cocaine.
[edit] Synthesis
Diethyl ether is typically prepared both in laboratories and on an industrial scale by the acid ether synthesis. Ethyl alcohol is mixed with a strong dehydrating acid, typically sulfuric acid, H2SO4. The acid releases hydrogen ions into solution at very high concentrations. Some of these ions, as H+, will seek out the relatively electronegative oxygen atoms on the ethyl alcohol molecules, creating a form of protonated ethanol with a positive charge:
CH3-CH2-OH + H+ --> CH3-CH2-OH2+
This species is highly electron-deficcent (electrophillic) and positively charged, so it will attract non-protonated ethanol molecules, which contain the nucleophilic hydroxyl group. The resulting attack will result in the production of diethyl ether and water:
CH3-CH2-OH2+ + CH3-CH2-OH --> H2O + H+ + CH3-CH2-O-CH2-CH3
Because the alcohol group is not a terribly good nucleophile (being uncharged), this reaction goes to equilibrium. In order to produce significant amounts of diethyl ether, distillation must be used to remove the low-boiling ether and drive the reaction forward. When performing this synthesis, it is advisible to use electric heating rather than an open-flame burner, as this will reduce (but by no means eliminate) the risk of fire. Also, note that the addition of sulfuric acid to the ethyl alcohol will release a great deal of heat, especially if the ethyl alcohol contains traces of water. Performing this addition carefully in an ice bath will prevent ether from boiling out prematurely.
[edit] Precautions
Diethyl ether is highly flammable. Its vapors are denser than air and will accumulate if proper ventilation is not present. Simple static electricity will ignite ether vapors. Diethyl ether vapors ignite explosively, and should only be used inside a fume hood.
Additionally, diethyl ether is prone to peroxide formation, and can form explosive diethyl ether peroxide. Ether peroxides are higher boiling and are contact explosives when dry. Ether should never be distilled to dryness, as the risk of explosion increases dramatically. Diethyl ether is typically supplied with BHT (2,6-di-tert-butyl-4-methylphenol), which reduces the formation of peroxides. Bottles older than 3 months should be routinely tested for peroxides. An iron wire, releasing Fe(III) ions catalyzing the peroxide decomposition, was often added to bottles with diethyl ether as a preventive measure, however, Fe(III) ions also strongly enhance peroxide formation. Storage over NaOH precipitates the intermediate ether hydroperoxides.
[edit] External links
| General anesthetics (N01A) | |
|---|---|
| Barbiturates | Hexobarbital, Methohexital, Narcobarbital, Thiopental |
| Ethers | Diethyl ether,Desflurane, Enflurane, Isoflurane, Methoxyflurane, Methoxypropane, Sevoflurane, Vinyl ether |
| Haloalkanes | Chloroform, Halothane, Trichloroethylene |
| Opioids | Alfentanil, Anileridine, Fentanyl, Phenoperidine, Remifentanil, Sufentanil |
| Others | Alfaxalone, Droperidol, Esketamine, Etomidate, Hydroxybutyric acid, Ketamine, Minaxolone, Nitrous oxide, Propanidid, Propofol, Xenon |
