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Skeletal formula
Ball-and-stick model
style="background: #F8EABA; text-align: center;" colspan="2" | Identifiers
CAS number 17455-13-9 YesY
PubChem 28557
ChemSpider 26563
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style="background: #F8EABA; text-align: center;" colspan="2" | Properties
Molecular formula C12H24O6
Molar mass 264.122 g/mol
Density 1.237 g/cm³
Melting point

37-40 °C

Boiling point

116 °C (0.2 Torr)

style="background: #F8EABA; text-align: center;" colspan="2" | Related compounds
Related compounds Dibenzo-18-crown-6
 YesY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

18-Crown-6 is an organic compound with the formula [C2H4O]6 and the IUPAC name of 1,4,7,10,13,16-hexaoxacyclooctadecane. The compound is a crown ether. Crown ethers coordinate some metal cations in their central cavity; 18-crown-6 displays a particular affinity for potassium cations. The synthesis of the crown ethers led to the Nobel Prize in Chemistry to Charles J. Pedersen.


This compound can be prepared by a modified Williamson ether synthesis[1] as well as the oligomerization of ethylene oxide in the presence of a templating cation.

It can be purified by distillation, where its tendency to supercool becomes evident. 18-Crown-6 can also be purified by precipitation with acetonitrile, with which it initially forms an insoluble complex. The acetonitrile may be removed in vacuo to obtain the desired compound.[1] Rigorously dry material can be made by dissolving the compound in THF followed by the addition of NaK to give [K(18-crown-6)]Na, an alkalide salt.


Crown ethers are useful as phase transfer catalysts.[2] In the presence of 18-crown-6 potassium permanganate dissolves in benzene, although this application is eclipsed by the use of quaternary ammonium/phosphonium salts.

18-crown-6 coordinating a potassium ion

Using 18-crown-6, potassium acetate is a more powerful nucleophile in organic solvents.

Related compounds

A related and generally superior complexant for alkali metal cations is dibenzo-18-crown-6.



  1. 1.0 1.1 George W. Gokel, Donald J. Cram, Charles L. Liotta, Henry P. Harris, and Fred L. Cook (1988), "18-Crown-6", Org. Synth. ; Coll. Vol., 6: 301  Missing or empty |title= (help)
  2. Liotta, C. L.; Berknerin, J. "18-Crown-6" in Encyclopedia of Reagents for Organic Synthesis (Ed: L. Paquette) 2004, J. Wiley & Sons, New York. doi:10.1002/047084289X.rc261

External links

fi:18-kruunu-6 pt:18-Coroa-6 uk:18-Краун-6 zh:18-冠-6