Diethyl ether, or simply ether, is an
organic compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. T ...
in the
ether class with the formula , sometimes abbreviated as (see
Pseudoelement symbols). It is a colourless, highly
volatile, sweet-smelling ("ethereal odour"), extremely
flammable liquid
A flammable liquid is a liquid which can be easily ignited in air at ambient temperatures, i.e. it has a flash point at or below nominal threshold temperatures defined by a number of national and international standards organisations.
The Occupat ...
. It is commonly used as a
solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for ...
in laboratories and as a
starting fluid for some engines. It was formerly used as a
general anesthetic, until non-flammable drugs were developed, such as
halothane. It has been used as a
recreational drug to cause
intoxication.
Production
Most diethyl ether is produced as a byproduct of the vapor-phase
hydration of
ethylene to make
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
. This process uses solid-supported
phosphoric acid
Phosphoric acid (orthophosphoric acid, monophosphoric acid or phosphoric(V) acid) is a colorless, odorless phosphorus-containing solid, and inorganic compound with the chemical formula . It is commonly encountered as an 85% aqueous solution, w ...
catalysts
Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...
and can be adjusted to make more ether if the need arises.
Vapor-phase
dehydration
In physiology, dehydration is a lack of total body water, with an accompanying disruption of metabolic processes. It occurs when free water loss exceeds free water intake, usually due to exercise, disease, or high environmental temperature. Mil ...
of ethanol over some
alumina catalysts can give diethyl ether yields of up to 95%.
Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis.
Ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
is mixed with a strong acid, typically
sulfuric acid, H
2SO
4. The acid
dissociates in the aqueous environment producing
hydronium ions, H
3O
+. A hydrogen ion
protonates the
electronegative oxygen atom of the
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
, giving the ethanol molecule a positive charge:
:
A
nucleophilic
In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...
oxygen atom of unprotonated ethanol
displaces a water molecule from the protonated (
electrophilic) ethanol molecule, reforming the hydronium ion and yielding diethyl ether.
:
This reaction must be carried out at temperatures lower than 150 °C in order to ensure that an elimination product (
ethylene) is not a product of the reaction. At higher temperatures, ethanol will dehydrate to form ethylene. The reaction to make diethyl ether is reversible, so eventually an
equilibrium between reactants and products is achieved. Getting a good yield of ether requires that ether be distilled out of the reaction mixture before it reverts to ethanol, taking advantage of
Le Chatelier's principle.
Another reaction that can be used for the preparation of ethers is the
Williamson ether synthesis
The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol (alkoxide). This reaction was developed by Alexander Williamson in 1850. Typically it involves the reaction of an alkoxide io ...
, in which an
alkoxide (produced by dissolving an
alkali metal in the alcohol to be used) performs a
nucleophilic substitution
In chemistry, a nucleophilic substitution is a class of chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group within another electron-deficient molecule (known as the electrophile). The ...
upon an
alkyl halide
The haloalkanes (also known as halogenoalkanes or alkyl halides) are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely us ...
.
Uses
It is particularly important as a solvent in the production of cellulose plastics such as
cellulose acetate
In biochemistry, cellulose acetate refers to any acetate ester of cellulose, usually cellulose diacetate. It was first prepared in 1865. A bioplastic, cellulose acetate is used as a film base in photography, as a component in some coatings, and ...
.
Fuel
Diethyl ether has a high
cetane number
Cetane number (cetane rating) is an indicator of the combustion speed of diesel fuel and compression needed for ignition. It plays a similar role for diesel as octane rating does for gasoline. The CN is an important factor in determining the quali ...
of 85–96 and is used as a
starting fluid, in combination with petroleum distillates for gasoline and diesel engines because of its high volatility and low
flash point. Ether starting fluid is sold and used in countries with cold climates, as it can help with cold starting an engine at sub-zero temperatures. For the same reason it is also used as a component of the fuel mixture for
carbureted compression ignition model engines. In this way diethyl ether is very similar to one of its precursors,
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
.
Chemistry
Diethyl ether is a
hard Lewis base that reacts with a variety of Lewis acids such as
iodine,
phenol
Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula . It is a white crystalline solid that is volatile. The molecule consists of a phenyl group () bonded to a hydroxy group (). Mildly acidic, it ...
, and
trimethylaluminium, and its base parameters in the
ECW model are E
B = 1.80 and C
B = 1.63. Diethyl ether is a common laboratory
aprotic solvent. It has limited
solubility
In chemistry, solubility is the ability of a substance, the solute, to form a solution with another substance, the solvent. Insolubility is the opposite property, the inability of the solute to form such a solution.
The extent of the solub ...
in
water
Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
(6.05 g/100 ml at 25 °C
[) and dissolves 1.5 g/100 g (1.0 g/100 ml) water at 25 °C.] This, coupled with its high volatility, makes it ideal for use as the non-polar solvent in liquid-liquid extraction. When used with an aqueous solution, the diethyl ether layer is on top as it has a lower density
Density (volumetric mass density or specific mass) is the substance's mass per unit of volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' can also be used. Mathematical ...
than the water. It is also a common solvent for the Grignard reaction
The Grignard reaction () is an organometallic chemical reaction in which alkyl, allyl, vinyl, or aryl-magnesium halides (Grignard reagent) is added to a carbonyl group in an aldehyde or ketone. This reaction is important for the formation of ...
in addition to other reactions involving organometallic reagents. Due to its application in the manufacturing of illicit substances, it is listed in the Table II precursor under the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances as well as substances such as acetone
Acetone (2-propanone or dimethyl ketone), is an organic compound with the formula . It is the simplest and smallest ketone (). It is a colorless, highly volatile and flammable liquid with a characteristic pungent odour.
Acetone is miscib ...
, toluene
Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) a ...
and sulfuric acid.
Anesthesia
William T. G. Morton participated in a public demonstration of ether anesthesia on October 16, 1846, at the Ether Dome in Boston, Massachusetts. However, Crawford Williamson Long is now known to have demonstrated its use privately as a general anesthetic in surgery to officials in Georgia, as early as March 30, 1842, and Long publicly demonstrated ether's use as a surgical anesthetic on six occasions before the Boston demonstration.[Hill, John W. and Kolb, Doris K. ''Chemistry for Changing Times: 10th Edition''. p. 257. Pearson: Prentice Hall. Upper Saddle River, New Jersey. 2004.] British doctors were aware of the anesthetic properties of ether as early as 1840 where it was widely prescribed in conjunction with opium.[Grattan, N. "Treatment of Uterine Haemorrhage". ''Provincial Medicine and Surgical Journal''. Vol. 1, No. 6 (Nov. 7, 1840), p. 107.] Diethyl ether largely supplanted the use of chloroform as a general anesthetic due to ether's more favorable therapeutic index, that is, a greater difference between an effective dose and a potentially toxic dose.
Diethyl ether does not depress the myocardium but rather it stimulates the sympathetic nervous system leading to hypertension and tachycardia. It is safely used in patients with shock as it preserves the baroreceptor reflex. Its minimal effect on myocardial depression and respiratory drive, as well as its low cost and high therapeutic index allows it to see continued use in developing countries. Diethyl ether could also be mixed with other anesthetic agents such as chloroform to make C.E. mixture, or chloroform and alcohol to make A.C.E. mixture. In the 21st century, ether is rarely used. The use of flammable ether was displaced by nonflammable fluorinated hydrocarbon anesthetics. Halothane was the first such anesthetic developed and other currently used inhaled anesthetics, such as isoflurane, desflurane, and sevoflurane, are halogenated ethers.[Morgan, G. Edward, Jr. et al. (2002). ''Clinical Anesthesiology'' 3rd Ed. New York: Mc Graw-Hill. p. 3.] Diethyl ether was found to have undesirable side effects, such as post-anesthetic nausea and vomiting. Modern anesthetic agents reduce these side effects.[
Prior to 2005 it was on the ]World Health Organization's List of Essential Medicines
The WHO Model List of Essential Medicines (aka Essential Medicines List or EML), published by the World Health Organization (WHO), contains the medications considered to be most effective and safe to meet the most important needs in a health s ...
for use as an anesthetic.
Medicine
Ether was once used in pharmaceutical formulations. A mixture of alcohol and ether, one part of diethyl ether and three parts of ethanol, was known as "Spirit of ether", Hoffman's Anodyne
An anodyne is a drug used to lessen pain through reducing the sensitivity of the brain or nervous system. The term was common in medicine before the 20th century, but such drugs are now more often known as analgesics or painkillers.
The term '' ...
or Hoffman's Drops. In the United States this concoction was removed from the Pharmacopeia at some point prior to June 1917, as a study published by William Procter, Jr. in the ''American Journal of Pharmacy'' as early as 1852 showed that there were differences in formulation to be found between commercial manufacturers, between international pharmacopoeia
A pharmacopoeia, pharmacopeia, or pharmacopoea (from the obsolete typography ''pharmacopœia'', meaning "drug-making"), in its modern technical sense, is a book containing directions for the identification of compound medicines, and published by ...
, and from Hoffman's original recipe. It is also used to treat hiccups
A hiccup (scientific name ''singultus'', from a Latin word meaning "to catch one's breath while sobbing"; also spelled hiccough) is an involuntary contraction ( myoclonic jerk) of the diaphragm that may repeat several times per minute. The hi ...
through instillation into nasal cavity.
Recreation
The anesthetic and intoxicating effects of ether have made it a recreational drug. Diethyl ether in anesthetic dosage is an inhalant which has a long history of recreational use. One disadvantage is the high flammability, especially in conjunction with oxygen. One advantage is a well-defined margin between therapeutic and toxic doses, which means one would lose consciousness before dangerous levels of dissolved ether in blood would be reached. With a strong, dense smell, ether causes irritation to respiratory mucosa and is uncomfortable to breathe, and in overdose triggering salivation, vomiting, coughing or spasms. In concentrations of 3–5% in air, an anesthetic effect can slowly be achieved in 15–20 minutes of breathing approximately 15–20 ml of ether, depending on body weight and physical condition. Ether causes a very long excitation stage prior to blacking out.
The recreational use of ether also took place at organised parties in the 19th century called ether frolics, where guests were encouraged to inhale therapeutic amounts of diethyl ether or nitrous oxide
Nitrous oxide (dinitrogen oxide or dinitrogen monoxide), commonly known as laughing gas, nitrous, or nos, is a chemical compound, an oxide of nitrogen with the formula . At room temperature, it is a colourless non-flammable gas, and has ...
, producing a state of excitation. Long, as well as fellow dentists Horace Wells
Horace Wells (January 21, 1815 – January 24, 1848) was an American dentist who pioneered the use of anesthesia in dentistry, specifically the use of nitrous oxide (or laughing gas).
Early life
Wells was the first of three children of H ...
, William Edward Clarke and William T. G. Morton observed that during these gatherings, people would often experience minor injuries but appear to show no reaction to the injury, nor memory that it had happened, demonstrating ether's anaesthetic effects.
In the 19th century and early 20th century ether drinking was popular among Polish peasants. It is a traditional and still relatively popular recreational drug among Lemkos
Lemkos ( rue, Лeмкы, translit= Lemkŷ; pl, Łemkowie; uk, Лемки, translit=Lemky) are an ethnic group inhabiting the Lemko Region ( rue, Лемковина, translit=Lemkovyna; uk, Лемківщина, translit=Lemkivshchyna) of Car ...
. It is usually consumed in a small quantity ('' kropka'', or "dot") poured over milk
Milk is a white liquid food produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals (including breastfed human infants) before they are able to digest solid food. Immune factors and immune-modula ...
, sugar water, or orange juice
Orange juice is a liquid extract of the orange tree fruit, produced by squeezing or reaming oranges. It comes in several different varieties, including blood orange, navel oranges, valencia orange, clementine, and tangerine. As well as vari ...
in a shot glass
A shot glass is a glass originally designed to hold or measure spirits or liquor, which is either imbibed straight from the glass ("a shot") or poured into a cocktail ("a drink"). An alcoholic beverage served in a shot glass and typically cons ...
. As a drug, it has been known to cause psychological dependence
Psychological dependence is a cognitive disorder that involves emotional–motivational withdrawal symptoms—e.g. anxiety and anhedonia—upon cessation of prolonged drug abuse or certain repetitive behaviors. It develops through frequent exp ...
, sometimes referred to as etheromania.
Metabolism
A cytochrome P450
Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various co ...
enzyme is proposed to metabolize diethyl ether.
Diethyl ether inhibits alcohol dehydrogenase
Alcohol dehydrogenases (ADH) () are a group of dehydrogenase enzymes that occur in many organisms and facilitate the interconversion between alcohols and aldehydes or ketones with the reduction of nicotinamide adenine dinucleotide (NAD+) to NA ...
, and thus slows the metabolism of ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
. It also inhibits metabolism of other drugs requiring oxidative metabolism.
For example, diazepam
Diazepam, first marketed as Valium, is a medicine of the benzodiazepine family that acts as an anxiolytic. It is commonly used to treat a range of conditions, including anxiety, seizures, alcohol withdrawal syndrome, muscle spasms, insomnia, ...
requires hepatic oxidization whereas its oxidized metabolite oxazepam
Oxazepam is a short-to-intermediate-acting benzodiazepine. Oxazepam is used for the treatment of anxiety and insomnia and in the control of symptoms of alcohol withdrawal syndrome.
It is a metabolite of diazepam, prazepam, and temazepam, and ha ...
does not.
Safety and stability
Diethyl ether is extremely flammable and may form explosive vapour/air mixtures.
Since ether is heavier than air it can collect low to the ground and the vapour may travel considerable distances to ignition sources. Ether will ignite if exposed to an open flame, though due its high flammability, an open flame is not required for ignition. Other possible ignition sources include - but are not limited to - hot plates, steam pipes, heaters, and electrical arcs created by switches or outlets. Vapour may also be ignited by the static electricity which can build up when ether is being poured from one vessel into another. The autoignition temperature of diethyl ether is . The diffusion of diethyl ether in air is (298 K, 101.325 kPa).
Ether is sensitive to light and air, tending to form explosive peroxides. Ether peroxides have a higher boiling point than ether and are contact explosives when dry. Commercial diethyl ether is typically supplied with trace amounts of the antioxidant butylated hydroxytoluene (BHT), which reduces the formation of peroxides. Storage over sodium hydroxide precipitates the intermediate ether hydroperoxides. Water and peroxides can be removed by either distillation from sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...
and benzophenone
Benzophenone is the organic compound with the formula (C6H5)2CO, generally abbreviated Ph2CO. It is a white solid that is soluble in organic solvents. Benzophenone is a widely used building block in organic chemistry, being the parent diarylket ...
, or by passing through a column of activated alumina.
History
The compound may have been synthesised by either Jābir ibn Hayyān
Abū Mūsā Jābir ibn Ḥayyān (Arabic: , variously called al-Ṣūfī, al-Azdī, al-Kūfī, or al-Ṭūsī), died 806−816, is the purported author of an enormous number and variety of works in Arabic, often called the Jabirian corpus. The ...
in the 8th century or Ramon Llull in 1275. It was synthesised in 1540 by Valerius Cordus, who called it "sweet oil of vitriol" (''oleum dulce vitrioli'')—the name reflects the fact that it is obtained by distilling a mixture of ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an alcohol with the chemical formula . Its formula can be also written as or (an ethyl group linked to a ...
and sulfuric acid (then known as oil of vitriol)—and noted some of its medicinal properties.[ At about the same time, Paracelsus discovered the analgesic properties of the molecule in dogs.][ The name ''ether'' was given to the substance in 1729 by August Sigmund Frobenius.]
It was considered to be a sulfur compound until the idea was disproved in about 1800.
References
External links
Michael Faraday's announcement of ether as an anesthetic in 1818
* Calculation o
vapor pressure
liquid density
dynamic liquid viscosity
surface tension
of diethyl ether, ddbonline.ddbst.de
{{DEFAULTSORT:Diethyl Ether
Dialkyl ethers
General anesthetics
Dissociative drugs
Euphoriants
Fuels
Ether solvents
GABAA receptor positive allosteric modulators
NMDA receptor antagonists
Glycine receptor agonists
Symmetrical ethers
Sweet-smelling chemicals