Difference between revisions of "Diethyl ether"
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Revision as of 18:52, 16 June 2019
Diethyl ether distilled from starting fluid
| IUPAC name
| Other names
3-Oxapentane; Diethyl oxide; Dether; Ethyl ether; Ethyl oxide; Ethoxyethane; Solvent ether; Sweet oil of vitriol
|Molar mass||74.12 g/mol|
|Appearance||Colorless volatile liquid|
|Melting point||−116.3 °C (−177.3 °F; 156.8 K)|
|Boiling point||34.6 °C (94.3 °F; 307.8 K)|
|6.9 g/100 ml (20 °C)|
|Solubility|| Miscible with ethanol, methanol, hexane, hydrocarbons|
Immiscible with dimethyl sulfoxide
|Vapor pressure||440 mmHg (20 °C)|
|Viscosity||0.224 cP (25 °C)|
Std enthalpy of
|-271.2 ± 1.9 kJ/mol|
|Safety data sheet||Sigma-Aldrich|
|Flash point||−45 °C|
|Lethal dose or concentration (LD, LC):|
LD50 (Median dose)
| 73,000 ppm (rat, 2 hr)|
6500 ppm (mouse, 1.65 hr)
| Dimethyl ether|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Diethyl ether is an organic compound with the chemical formula (C2H5)2O. It is a volatile colorless liquid at room temperature and is most commonly used in the lab as a nonpolar solvent. It is one of the most common ethers.
Diethyl ether is commonly used as an extraction solvent, though it is rather expensive for use as such. It is often used as a solvent in Grignard reactions, however it must be dried and distilled over elemental sodium immediately prior to use. As with all ethers, it may hydrolyze to ethanol in contact with extremely strong bases. Hydroiodic acid will cleave ethers.
Diethyl ether is a colorless liquid which is less dense than water. It is slightly soluble in water, and will dissolve an even lower amount of water. Diethyl ether is extremely volatile and thus, due to its nervous system depression effects, large amounts should only be used outside or in a fume hood. The volatility of diethyl ether and its reputation for high flammability make it one of the riskier solvents to make use of. It has a distinctive, sweet smell characteristic of ethers.
Diethyl ether is fairly widely available from chemical suppliers, however it is usually very expensive. If reasonably pure but not reagent grade ether is acceptable, it can easily be distilled from many engine starter fluids found at automotive stores, gas stations, and department stores. It is often found alongside isomers of heptane, methylcyclohexane, and other hydrocarbons, but the very low boiling point of diethyl ether makes it easy to isolate.
Attention: do not spray the content of the can into a flask! This way, a lot of ether is lost (sciencemadness user Ave369 only distilled 50 ml of diethyl ether from a can of Quick-Start emptied that way). Penetrate the can accurately, let all the propellant gas out, then pour the content out.
A good tip is to cool the can in a freezer first, to limit the evaporation of the fluid, then carefully inject the chilled fluid in the distillation flask using the can's long straw or another plastic straw, if the can doesn't come with one.
Some types of starting fluid also have other impurities, like aldehydes, which usually come from the manufacturing process. They cannot be removed via distillation, but can be condensed by adding an alkali metal (like sodium) or a base (sodium hydroxide). After the whole solid polymerized, you should distill the product once more (you may filter the liquid if you desire), and this step should give you a much purer product.
Diethyl ether is fairly easily prepared from concentrated sulfuric acid and azeotropic ethanol (though anhydrous works better), with the ether being distilled off. A way to remove water is necessary for driving the reaction to completion, as the continual generation of water as a byproduct slows the reaction down. Care must be taken in this preparation, however, due to diethyl ether's incredibly high flammability and low flash point. Any distillation involving diethyl ether should not be walked away from. Boiling ether to dryness can cause explosions if sensitive peroxides are contained within, but this can be avoided by the addition of a small amount of higher-boiling solvent to the diethyl ether prior to distilling, such as mineral oil or glycerol. This additional solvent will be left behind post-distillation to solvate any peroxides and reduce their danger. This reaction must be performed between 135 °C and 150 °C to maintain an acceptable ether formation rate and reduce the production of ethylene gas.
- Destruction of Styrofoam on contact
- Organic extractions
- Solvent for Grignard reactions and Grignard reagents
Diethyl ether is highly flammable and can easily be ignited by electrical devices such as light switches, or hot surfaces such as hot plates. Diethyl ether vapors are also denser than air, and thus pool on the ground where hot surfaces are more likely to be present. Diethyl ether is also a slight nervous system depressant, however it does not present a significant health risk. It has narcotic properties and has been known to cause temporary dependence, condition sometimes referred to as etheromania.
Diethyl ether is best stored in narrow neck reagent glass bottles. Diethyl ether will slowly form explosive peroxides in storage, though addition of a small amount of butylated hydroxytoluene (BHT) or storage over sodium hydroxide will prevent this. Care must be taken not to distill ether to dryness due to the trace amounts of peroxides formed over time. Iron, copper, ferrous salts, and sulfites are known to inhibit the formation of peroxides.
Diethyl ether can be safely burned, unless it has peroxides. If the ether tests positive for peroxides but there is no precipitate in the ether, it's possible to neutralize the dissolved peroxides. Reducing agents, like ferrous sulfate, sodium bisulfite or metabisulfite added in excess can be used to neutralize the peroxides. After neutralization, the ether should be tested again for peroxides and if none are present, it can be safely burned.
If it's an old bottle, which has visible peroxide in the solution, or if very old, is very likely to have peroxides on the cap, DO NOT OPEN THE BOTTLE! Instead take it to a remote of special area and safely detonate it. The latter may or may not require professional help, depending on the severity of the case.