Diethyl ether

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Diethyl ether
Skeletal formula
Ball-and-stick model
Diethyl Ether Electron Rendering
Identifiers
CAS number 60-29-7 YesY
PubChem 3283
ChemSpider 3168 YesY
UNII 0F5N573A2Y YesY
KEGG D01772 YesY
ChEBI CHEBI:35702 YesY
ChEMBL CHEMBL16264 YesY
RTECS number KI5775000
ATC code N01AA01
Jmol-3D images Image 1
Properties
Molecular formula C4H10O
Molar mass 74.12 g mol−1
Appearance Colorless liquid
Density 0.7134 g/cm3, liquid
Melting point −116.3 °C, 156.9 K, −177.3 °F
Boiling point 34.6 °C, 307.8 K, 94.3 °F
Solubility in water 69 g/L (20 °C)
Refractive index (nD) 1.353 (20 °C)
Viscosity 0.224 cP (25 °C)
Structure
Dipole moment 1.15 D (gas)
Thermochemistry
Specific
heat capacity
C
172.5 J/mol·K
Std molar
entropy
So298
253.5 J/mol·K
Std enthalpy of
formation
ΔfHo298
-271.2 ± 1.9 kJ/mol
Std enthalpy of
combustion
ΔcHo298
-2732.1 ± 1.9 kJ/mol
Hazards
MSDS External MSDS
R-phrases R12 R19 R20/22 R66 R67
S-phrases S9 S16 S29 S33
Main hazards Extremely Flammable, harmful to skin
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point −45 °C[1]
Autoignition temperature 160 °C[1]
Explosive limits 1.9-48.0% [2]
Related compounds
Related Ethers Dimethyl ether
Methoxypropane
Related compounds Diethyl sulfide
Butanols (isomer)
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Diethyl ether, also known as ethyl ether, sulfuric ether, simply ether, or ethoxyethane, is an organic compound in the ether class with the formula (C
2
H
5
)
2
O
. It is a colorless, highly volatile flammable liquid. It is commonly used as a solvent and was once used as a general anesthetic. It has narcotic properties and has been known to cause temporary DSM-IV dependance, the only symptom of which is the will to do more, sometimes referred to as etheromania.

History[edit]

The compound may have been created by either Jābir ibn Hayyān in the 8th century[3] or Raymundus Lullus in 1275,[3][4] although there is no contemporary evidence of this. It was first synthesized 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 and sulfuric acid (then known as oil of vitriol) — and noted some of its medicinal properties.[3] At about the same time, Paracelsus discovered ether's analgesic properties in chickens.[3] The name ether was given to the substance in 1729 by August Sigmund Frobenius.[5]

Applications[edit]

It is particularly important as a solvent in the production of cellulose plastics such as cellulose acetate.[6]

As a fuel[edit]

Diethyl ether has a high cetane number of 85-96 and is used as a starting fluid, in combination with petroleum distillates for gasoline and diesel engines[7] because of its high volatility and low flash point. For the same reason it is also used as a component of the fuel mixture for carbureted compression ignition model engines.

Laboratory uses[edit]

Diethyl ether is a common laboratory solvent. It has limited solubility in water (6.05 g/100 mL at 25 °C.) [8] and dissolves 1.5 g/100 mL water at 25 °C.[9] Therefore, it is commonly used for liquid-liquid extraction. When used with an aqueous solution, the organic layer is on top as the diethyl ether has a lower density than the water. It is also a common solvent for the Grignard reaction 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.[10]

Anesthetic use[edit]

Panel from monument in Boston commemorating Morton's demonstration of ether's anesthetic use.

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, M.D., 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 numerous occasions before 1846.[11] British doctors were aware of the anesthetic properties of ether as early as 1840 where it was widely prescribed in conjunction with opium.[12] Diethyl ether was formerly sometimes used in place of chloroform because it had a higher therapeutic index, that is, a larger difference between the recommended dosage and a toxic overdose.[13] Because of its associations with Boston, the use of ether became known as the "Yankee Dodge."

Diethyl ether depresses the myocardium and increases tracheobronchial secretions.[14]

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.

Today, 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 also fluorinated hydrocarbons.[15] Diethyl ether was found to have undesirable side effects, such as post-anesthetic nausea and vomiting. Modern anesthetic agents reduce these side effects.[11]

Medical use[edit]

It was once used in pharmaceuticals. A mixture of alcohol and ether was known as "Spirit of ether" or Hoffman's Drops. In the United States, it was removed from Pharmacopeia prior to June 1917.[16]

Recreational use[edit]

The anesthetic 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 pass out 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 15-20ml of ether, depending on body weight and physical condition. Ether causes a very long excitation stage prior to blacking out.

In the 19th century and early 20th century ether drinking was popular among Polish peasants.[17] It is a traditional and still relatively popular recreational drug among Lemkos.[18] It is usually consumed in a small quantity (kropka, or "dot") poured over milk, water with sugar or orange juice in a shot glass.

Metabolism[edit]

A cytochrome P450 enzyme is proposed to metabolize diethyl ether.[19]

Diethyl ether inhibits alcohol dehydrogenase, and thus slows the metabolism of ethanol .[20] It also inhibits metabolism of other drugs requiring oxidative metabolism. For example diazepam requires hepatic oxidization whereas its oxidized metabolite oxazepam does not.[21]

Production[edit]

Most diethyl ether is produced as a byproduct of the vapor-phase hydration of ethylene to make ethanol. This process uses solid-supported phosphoric acid catalysts and can be adjusted to make more ether if the need arises.[6] Vapor-phase dehydration of ethanol over some alumina catalysts can give diethyl ether yields of up to 95%.[22]

Diethyl ether can be prepared both in laboratories and on an industrial scale by the acid ether synthesis.[23] Ethanol is mixed with a strong acid, typically sulfuric acid, H2SO4. The acid dissociates in the aqueous environment producing hydronium ions, H3O+. A hydrogen ion protonates the electronegative oxygen atom of the ethanol, giving the ethanol molecule a positive charge:

CH3CH2OH + H3O+ → CH3CH2OH2+ + H2O

A nucleophilic oxygen atom of unprotonated ethanol displaces a water molecule from the protonated (electrophilic) ethanol molecule, producing water, a hydrogen ion and diethyl ether.

CH3CH2OH2+ + CH3CH2OH → H2O + H+ + CH3CH2OCH2CH3

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, in which an alkoxide (produced by dissolving an alkali metal in the alcohol to be used) performs a nucleophilic substitution upon an alkyl halide.

Safety and stability[edit]

Diethyl ether is extremely flammable and may be explosive.[24]

Since ether is heavier than air it can collect low to the ground and the vapour may travel considerable distances to ignition sources, which need not be an open flame, but may be a hot plate, steam pipe, heater etc.[24] Vapour may 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 160 °C (320 °F). A common practice in chemical labs is to use steam (thus limiting the temperature to 100 °C (212 °F) ) when ether must be heated or distilled. The diffusion of diethyl ether in air is 0.918·10−5 m2/s (298K, 101.325 kPa).[citation needed]

Ether is sensitive to light and air, tending to form explosive peroxides.[24] Ether peroxides are higher boiling than ether and are contact explosives when dry.[24] 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 and benzophenone, or by passing through a column of activated alumina.[25]

References[edit]

  1. ^ a b "Ethyl Ether MSDS". J.T. Baker. Retrieved 2010-06-24. 
  2. ^ Carl L. Yaws, Chemical Properties Handbook, McGraw-Hill, New York, 1999, page 567
  3. ^ a b c d Toski, Judith A; Bacon, Douglas R; Calverley, Rod K (2001). "The history of Anesthesiology". In: Barash, Paul G; Cullen, Bruce F; Stoelting, Robert K. Clinical Anesthesia (4 ed.) (Lippincott Williams & Wilkins). p. 3. ISBN 978-0-7817-2268-1. 
  4. ^ Hademenos, George J.; Murphree, Shaun; Zahler, Kathy; Warner, Jennifer M. (2008-11-12). McGraw-Hill's PCAT. McGraw-Hill. p. 39. ISBN 978-0-07-160045-3. Retrieved 2011-05-25. 
  5. ^ Dr. Frobenius (1729) "An account of a spiritus vini æthereus, together with several experiments tried therewith," Philosophical Transactions of the Royal Society (London), 36 : 283-289.
  6. ^ a b "Ethers, by Lawrence Karas and W. J. Piel". Kirk‑Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 2004. 
  7. ^ "Extra Strength Starting Fluid: How it Works". Valvovine. Archived from the original on 2007-09-27. Retrieved 2007-09-05. 
  8. ^ The Merck Index, 10th Edition, Martha Windholz, editor, Merck & Co., Inc, Rahway, NJ, 1983, page 551
  9. ^ H. H. Rowley, Wm. R. Reed (1951). "Solubility of Water in Diethyl Ether at 25 °". J. Am. Chem. Soc. 73 (6): 2960–2960. doi:10.1021/ja01150a531. 
  10. ^ Microsoft Word - RedListE2007.doc
  11. ^ a b Hill, John W. and Kolb, Doris K. Chemistry for changing times: 10th edition. Page 257. Pearson: Prentice Hall. Upper saddle river, New Jersey. 2004.
  12. ^ Grattan, N. Treatment of Uterine Haemorrhage. Provincial Medicine and Surgical Journal. Vol. 1, No. 6 (Nov. 7, 1840), p. 107.
  13. ^ Calderone, F.A. (1935). J. Pharmacology Experimental Therapeutics 55 (1): 24–39 Jpet.aspetjournals.org http://jpet.aspetjournals.org/cgi/reprint/55/1/24.pdf Jpet.aspetjournals.org |url= missing title (help). 
  14. ^ Ether and its effects in Anesthesia. 
  15. ^ Morgan, G. Edward, Jr. et al. "Clinical Anesthesiology" 3rd Ed, p. 3. New York: Mc Graw-Hill. 2002
  16. ^ The National druggist, Volume 47, June 1917, pp.220
  17. ^ Zandberg, Adrian (2010). "Short Article "Villages … Reek of Ether Vapours": Ether Drinking in Silesia before 1939". Medical History 54 (3): 387–396. doi:10.1017/s002572730000466x. PMC 2890321. PMID 20592886. 
  18. ^ Kaszycki, Nestor (2006-08-30). "Łemkowska Watra w Żdyni 2006 – pilnowanie ognia pamięci". Histmag.org – historia od podszewki (in Polish). Kraków, Poland: i-Press. Retrieved 2009-11-25. "Dawniej eteru używało się w lecznictwie do narkozy, ponieważ ma właściwości halucynogenne, a już kilka kropel inhalacji wystarczyło do silnego znieczulenia pacjenta. Jednak eter, jak każda ciecz, może teoretycznie być napojem. Łemkowie tę teorię praktykują. Mimo to, nazywanie skroplonego eteru – „kropki” – ich „napojem narodowym” byłoby przesadą. Chociaż stanowi to pewną część mitu „bycia Łemkiem”." 
  19. ^ 109. Aspergillus flavus mutant strain 241, blocked in aflatoxin biosynthesis, does not accumulate aflR transcript. Matthew P. Brown and Gary A. Payne, North Carolina State University, Raleigh, NC 27695 fgsc.net
  20. ^ P. T. Normann, A. Ripel and J. Morland (1987). "Diethyl Ether Inhibits Ethanol Metabolism in Vivo by Interaction with Alcohol Dehydrogenase". Alcoholism: Clinical and Experimental Research 11 (2): 163–166. doi:10.1111/j.1530-0277.1987.tb01282.x. PMID 3296835. 
  21. ^ Larry K. Keefer, William A. Garland, Neil F. Oldfield, James E. Swagzdis, and Bruce A. Mico (1985). "Inhibition of N-Nitrosodimethylamine Metabolism in Rats by Ether Anesthesia". Cancer Research 45 (11 Pt 1): 5457–60. PMID 4053020. 
  22. ^ Ethyl Ether, Chem. Economics Handbook. Menlo Park, Calif: SRI International. 1991. 
  23. ^ Cohen, Julius Berend (1920). A Class-book of Organic Chemistry, Volume 1. London: Macmillan and Co. p. 39. 
  24. ^ a b c d http://www.chem.purdue.edu/chemsafety/safetyclass/SDS/GHS-Et2O.pdf
  25. ^ W. L. F. Armarego and C. L. L. Chai (2003). Purification of laboratory chemicals. Boston: Butterworth-Heinemann. ISBN 978-0-7506-7571-0. 

External links[edit]