Diethyl ether

Structural formula
General
Surname	Diethyl ether
other names	Ethoxyethane ( IUPAC ) Ether ether Diethyl ether Et 2 O EtOEt R-610 3-oxapentane
Molecular formula	C 4 H 10 O
Brief description	colorless, easily mobile, sweet-smelling liquid
External identifiers / databases
CAS number 60-29-7 EC number 200-467-2 ECHA InfoCard 100,000,425 PubChem 3283 Wikidata Q202218
Drug information
ATC code	N01 AA01
Drug class	narcotic Dissociative
properties
Molar mass	74.12 g mol −1
Physical state	liquid
density	0.71 g cm −3 (20 ° C)
Melting point	−116 ° C
boiling point	35 ° C 34.6 ° C
Vapor pressure	586 h Pa (20 ° C) 859 hPa (30 ° C) 1223 hPa (40 ° C) 1698 hPa (50 ° C)
solubility	poor in water (69 g l −1 at 20 ° C) miscible with ethanol , well in acetone , methanol , chloroform , petroleum ether and concentrated aqueous hydrochloric acid
Dipole moment	1.098 (1) D (3.7 x 10 -30  C  ·  m )
Refractive index	1.3526 (20 ° C)
safety instructions
Please note the exemption from the labeling requirement for drugs, medical devices, cosmetics, food and animal feed GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 224-302-336 EUH: 019-066 P: 210-240-403 + 235
MAK	DFG / Switzerland: 400 ml m −3 or 1200 mg m −3
Toxicological data	1250 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Diethyl ether is the most important representatives of the organic chemical compound class of ether and is therefore often referred to simply as ether (standard language and in the older scientific literature ether called). Because it is made from ethanol and sulfuric acid, a historical name is sulfur ether, although diethyl ether does not contain sulfur.

The first production is attributed to Valerius Cordus (1535), from the conversion of alcohol with sulfuric acid, rediscovered around 1730 by August Sigmund Frobenius in London. As he wrote in 1540, Paracelsus is said to have recognized the anesthetic effect of ether in animal experiments. The first use for modern anesthesia was in 1842 by Crawford W. Long .

Manufacturing

Diethyl ether can be prepared from ethanol and concentrated sulfuric acid with elimination of water, the alcohol being added in portions to the sulfuric acid and the product being separated off from the reaction mixture by distillation. During this acidic etherification , ethylsulfuric acid is first formed in a condensation reaction :

${\displaystyle \mathrm {H_{3}C{-}CH_{2}{-}OH\!\ +\!\ HO{-}SO_{2}{-}OH} }$

${\displaystyle \mathrm {\longrightarrow \!\ H_{3}C{-}CH_{2}{-}O{-}SO_{2}{-}OH+H_{2}O} }$

The alkyl sulfate reacts with ethanol to form diethyl ether, the sulfuric acid is released again:

${\displaystyle \mathrm {H_{3}C{-}CH_{2}{-}O{-}SO_{2}{-}OH\!\ +\!\ H_{3}C{-}CH_{2}{-}OH} }$

${\displaystyle \mathrm {\longrightarrow \!\ H_{3}C{-}CH_{2}{-}O{-}CH_{2}{-}CH_{3}\!\ +\!\ H_{2}SO_{4}} }$

The main source of diethyl ether today is the synthesis of ethanol from ethene , in which diethyl ether occurs as a by-product. In the first step, ethyl sulfuric acid is also formed here:

${\displaystyle \mathrm {H_{2}C{=}CH_{2}\!\ +\!\ H_{2}SO_{4}\!\ \longrightarrow \!\ H_{3}C{-}CH_{2}{-}O{-}SO_{2}{-}OH} }$

Hydrolysis of the intermediate product leads to ethanol, some of the ethanol reacts - as in the synthesis from ethanol above - with ethylsulfuric acid to form diethyl ether.

properties

Chemical and physical properties

Diethyl ether is a colorless, volatile and extremely flammable liquid at room temperature, but apart from that it is very inert. Its vapors are heavier than air. However , when exposed to light in the presence of atmospheric oxygen , organic peroxides are formed , which can easily and explosively decompose. That is why ether is kept in dark bottles. To avoid a build-up of peroxides, diethyl ether can be stored over potassium hydroxide . The peroxides then form sparingly soluble potassium peroxides. However, before use ( distillation ), the presence of peroxides must be checked.

Safety-related parameters

Diethyl ether forms highly flammable vapor-air mixtures. The compound has a flash point of −40 ° C. The explosion range is between 1.7% by volume (50 g / m ³ ) as the lower explosion limit (LEL) and 39.2% by volume (1210 g / m ³ ) as the upper explosion limit (UEL). According to the vapor pressure function, there is a lower explosion point of −45 ° C. The maximum explosion pressure is 10 bar. The limit gap width was determined to be 0.87 mm. This results in an assignment to explosion group IIB. With a minimum ignition energy of 0.19 mJ, vapor-air mixtures are extremely ignitable. The ignition temperature is 175 ° C. The substance therefore falls into temperature class T4.

Physiological properties

Inhaling the vapors in small doses causes intoxicating states with strong emotional excitement, altered awareness and confused, psychotic-seeming thought processes. Very unpleasant, sometimes traumatizing anxiety states are also not uncommon. At higher doses, the consumer enters an apathetic state in which he is no longer responsive (narcotization). Side effects of consumption are irritated mucous membranes when sniffing and inflammation of the gastric mucosa when drinking.

When inhaled, diethyl ether is quickly absorbed in the body and around 90 percent of it is excreted unchanged in the air. Diethyl ether that is not excreted is converted to hydroxy diethyl ether by a cytochrome P450 -dependent monooxygenase and then to ethanal and ethanol with the aid of dealkylation .

use

Use in medicine

Diethyl ether was previously widely used as a tonic ( Hoffmann's drops ) and, since 1846, it has also been used routinely as an anesthetic during anesthesia in the context of surgical interventions. The first documented ether anesthesia was performed shortly after William E. Clarke (* 1818) in Rochester / NY for the treatment of a carious tooth of the patient Hobbie by the dentist Elija Pope for the first time (before 1842?) Carried out an ether anesthesia, Crawford Williamson Long on March 30, 1842. (However, this application was not published until December 1849). That is why March 30th has been celebrated annually as Doctor's Day in the USA since 1991 . A few years later, on October 16, 1846, the first public ether anesthesia was performed by William Thomas Green Morton in the Massachusetts General Hospital in Boston. With October 16, 1846 (Ether Day) , modern anesthesia has an “official date of birth”. The discovery of the narcotic properties revolutionized medicine and especially surgery. Instead of patients who were only insufficiently anesthetized with spirits such as whiskey or opiates, as before , it was now possible to operate on unconscious patients much more easily and, above all, without pain, with much more time.

The Würzburg surgical assistant doctor and later ophthalmologist Robert Ritter von Welz , who researched the effects of ether as an anesthetic as early as January 1847, also used diethyl ether inhalation to alleviate shortness of breath in a dying tuberculosis patient. Welz describes it as follows: “With him I succeeded in transforming the agony, which had increased to the most terrible fear for lack of air, into a serene and painless state by inhaling ether for twenty minutes. During this inhalation the dying person was not only attacked by a cough, but on the contrary was able to draw deeper inspiration and expectorate the purulent mucus rattling in the bronchial trunks. Soon afterwards he passed away fully conscious, but surrounded by cheerful pictures [...]. ”In 1847, aether was used by the obstetrician Walter Channing (1786–1876) to treat cramps in pregnant women .

The highly volatile ether was first administered via an inhalation system - as described by Robert Ritter von Welz - the liquid ether was absorbed by a sponge and then fed to the patient via a hose. From 1908, the French pediatric surgeon and orthopedic surgeon Louis Ombrédanne (1871–1956) introduced another anesthetic system, the further development of which led to the emergence of closed anesthetic systems - for the first time in 1923 by Ralph Milton Waters (1883–1979). The Schimmelbusch mask, introduced especially for hygienic reasons , in which ether is dripped onto a cloth, was another way of administering the anesthetic.

Due to its long decay time, frequent, unpleasant after-effects (including vomiting, restlessness) and the risk of explosion when ether-air mixtures are formed, diethyl ether is nowadays generally used. d. Usually no longer used for anesthesia. For example, in the 1930s at the Charité, when using an incandescent cautery, ether vapors ignited during the operation of a twelve-year-old boy and an oxygen bottle burst as a result , killing the young patient and injuring several people. Another medical field of application of diethyl ether (as a non-polar solvent) is its function as a solubilizer in the production of tinctures etc., the active ingredients of which are difficult or impossible to dissolve in more polar solvents such as alcohol or glycerine , e.g. B. in the production of Arningscher tincture .

Use in chemistry

Diethyl ether is one of the most important solvents in preparative chemistry because of its low reactivity and its large liquid range. In particular, reactions with metal organyls such as Grignard compounds are carried out in anhydrous ether. Diethyl ether can also be used for liquid-liquid extraction . The use as a solvent in industrial processes is declining. In the meantime, methyl tert-butyl ether (MTBE) is being used more and more frequently , in which the formation of explosive peroxides is excluded, but which nevertheless shows very similar properties.

Use as an intoxicant

Diethyl ether is also consumed as an intoxicant . From the mid to late 19th century, diethyl ether was the most widely used intoxicant in Ireland due to high alcohol prices and was sold in stores. The ether was drunk together with water. The use of diethyl ether decreased from 1890, when it was classified as a poison and was only allowed for sale to chemists or pharmacists. In addition to Ireland, ether drinking was also widespread in Scotland , Russia and Norway . In France , ether was drunk with cognac , in Michigan (USA) with whiskey .

Other uses

Diethyl ether is used, among other things, as a starter spray for starting internal combustion engines.

Risk assessment

In 2017, diethyl ether was included in the EU's ongoing action plan ( CoRAP ) in accordance with Regulation (EC) No. 1907/2006 (REACH) as part of substance evaluation . The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. Diethyl ether ingestion was driven by concerns about consumer use , environmental exposure , high (aggregated) tonnage, other hazard-related concerns and widespread use, as well as the potential dangers of carcinogenic, mutagenic and reproductive properties. The re-evaluation is to be carried out by France from 2020 .

Historical literature

• Victor Nicolaus Kronser: The sulfur ether. Its chemical preparation, properties and use, along with detailed reports of the first and most interesting experiments in Vienna, among others, experiments made with it during operations and in various cases of illness, as well as their course and follow-up treatment. Jasper, Hügel & Manz, Vienna 1847 ( urn : nbn: de: hbz: 061: 2-7479 ).
• Matthew Turner: An account of the extraordinary medical fluid, called aether. London (J. Wilkie) 1843. Full text in Project Gutenberg ( currently not generally available for users from Germany )

Web links

Wiktionary: Diethylether  - explanations of meanings, word origins, synonyms, translations

• Diethyl ether data sheet (PDF) from Merck , accessed on January 19, 2011.

Individual evidence

1. ↑ ^{a b c} Entry on diethyl ether. In: Römpp Online . Georg Thieme Verlag, accessed on December 9, 2014.
2. ↑ ^{a b c d e f g h i j k l m n o} Entry for CAS no. 60-29-7 in the GESTIS substance database of the IFA , accessed on November 13, 2017(JavaScript required) .
3. ^ Siegfried Hauptmann : Organic Chemistry , 2nd revised edition, VEB Deutscher Verlag für Grundstoffindustrie, Leipzig, 1985, p. 340, ISBN 3-342-00280-8 .
4. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Dipole Moments, pp. 9-54.
5. ↑ Specifications for "Diethylether pure Ph. Eur." From the manufacturer AppliChem, accessed on February 19, 2016.
6. ↑ Entry on diethyl ether in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
7. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 60-29-7 or diethyl ether ), accessed on November 2, 2015.
8. ↑ Frobenius: An Account of a Spiritus Vini Æthereus, together with Several Experiments Tried Therewith: By Dr. Frobenius, FRS In: Philosophical Transactions of the Royal Society of London. 36, 1729-1730, pp. 283-289, doi : 10.1098 / rstl.1729.0045 .
9. ↑ Saarland University Hospital: History of Anesthesia .
10. ↑ Christoph Weißer: Aether anesthesia. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 16.
11. ^ ^{A b c d e} E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.
12. ↑ CP Chengelis, RA Neal: microsomal metabolism of diethyl ether. In: Biochemical pharmacology. Volume 29, Number 2, February 1980, pp. 247-248, PMID 6767481 .
13. ^ Richard J. Kitz, Leroy D. Vandam: A History and the Scope of Anesthetic Practice. In: Ronald D. Miller (Ed.): Anesthesia. 3 volumes, Churchill Livingstone, New York / Edinburgh / London / Melbourne 1981, 2nd edition ibid. 1986, ISBN 0-443-08328-2 , Volume 1, pp. 3–25, here: p. 6.
14. ↑ Christoph Weißer: Äthernarkose In: Werner E. Gerabek u. a. (Ed.): Encyclopedia of medical history. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , p. 16.
15. ^ Crawford W. Long: An Account of the First Use of Sulphuric Ether by Inhalation as an Anesthetic in Surgical Operations. In: Southern Medical and Surgical Journal. New Series, Volume 5, No. 12, (December) 1849, pp. 705-713 (the text is complete in Boland (1950), pp. 35-39, and in Albert Faulconer, Thomas Edward Keys (1965), p . 310-316, reprinted).
16. ^ The dentist who invented anesthesia , Süddeutsche Zeitung, September 13, 2016.
17. ^ Christoph Weißer: First Würzburg ether anesthesia in 1847 by Robert Ritter von Welz (1814–1878). In: Würzburger medical history reports 17, 1998, pp. 7-20.
18. ↑ Robert Ritter von Welz : The inhalation of the ether vapors in their various modes of action with practical instructions for those who use this means. Edited according to my own experience. Voigt & Mocker, Würzburg 1847, p. 21.
19. ↑ Horst Kremling : On the history of the gestosis. In: Würzburger medical history reports 17, 1998, pp. 261–274; here: p. 268.
20. ↑ Christoph Weißer: Ombrédanne, Louis. In: Werner E. Gerabek, Bernhard D. Haage, Gundolf Keil, Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte . De Gruyter, Berlin 2005, ISBN 3-11-015714-4 , p. 1069.
21. ↑ Christoph Weißer: Anesthesia. In: Werner E. Gerabek et al. (Ed.): Enzyklopädie Medizingeschichte . 2005, p. 54 f.
22. ^ Ferdinand Sauerbruch , Hans Rudolf Berndorff : That was my life. Kindler & Schiermeyer, Bad Wörishofen 1951; cited: Licensed edition for Bertelsmann-Lesering, Gütersloh 1956, p. 366.
23. ^ Robert A. Strickland: Ether Drinking in Ireland. In: Mayo Clinic Proceedings. 71, 1996, p. 1015, doi : 10.1016 / S0025-6196 (11) 63779-8 .
24. ↑ Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): Diethyl ether , accessed on March 26, 2019.

This article is about a health issue. It is not used for self-diagnosis and does not replace a diagnosis by a doctor. Please note the information on health issues !