|Molecular formula||C 4 H 10 O|
colorless, easily mobile, sweet-smelling liquid
|External identifiers / databases|
|Molar mass||74.12 g mol −1|
0.71 g cm −3 (20 ° C)
−116 ° C
1.3526 (20 ° C)
DFG / Switzerland: 400 ml m −3 or 1200 mg m −3
|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 .
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 :
The alkyl sulfate reacts with ethanol to form diethyl ether, the sulfuric acid is released again:
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:
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.
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.
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.
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 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 .
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 .
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