23.6 Ethers – Structure and Naming

With the general formula ROR ′, an ether may be considered a derivative of water in which both hydrogen atoms are replaced by alkyl or aryl groups (aryl means aromatic). It may also be considered a derivative of an alcohol ( ROH ) in which the hydrogen atom of the OH group is replaced by a second alkyl or aryl group (Figure 23.6a.).

Naming Ethers

The IUPAC naming process of naming ethers involves separately naming each of the two groups attached to the oxygen atom.

1. The group that has the longest continuous carbon chain is considered the parent chain and is named accordingly. (For example, if the longest chain consists of 3 carbons, the parent chain would be propane).
2. The group attached to the oxygen that has the shorter chain is named as an alkoxy group, which replaces the “ane” ending with “oxy”. For example, a one carbon chain would go from methane to methoxy.
3. Remaining substituents are numbered and named as in previous sections.

Example 23.6a

What is the IUPAC name for each ether?

Solution:

1. There is a two carbon group and a three carbon group on either side of the oxygen. The parent chain is based on the longer group (3 carbons = propane) and the alkoxy group is the shorter chain (2 carbons = ethoxy). The compound’s name would be ethoxypropane.
2. There is a six carbon group and a four carbon group on either side of the oxygen. The parent chain is based on the longer group (6 carbons = hexane) and the alkoxy group is the shorter chain (4 carbons = butoxy). The compound’s name would be butoxyhexane.

Exercise 23.6a

What is the IUPAC name for each ether?

1. CH₃CH₂CH₂CH₂OCH₂CH₂CH₂CH₃

Check Your Answers: [1]

Simple ethers also have common names, formed from the names of the groups attached to oxygen atom, followed by the generic name ether. If both groups are the same, the group name should be preceded by the prefix di-.

Example 23.6b

What is the common name for each ether?

Solutions:

1. methyl propyl ether
2. dimethyl ether
3. diethyl ether

Exercise 23.6b

What is the common name of this ether?

subscript 2 group. The C H subscript 2 group is bonded up and to the right to a C H subscript 3 group." width="325" height="62" />

Check Your Answer: [2]

Source: Exercise 23.6b is adapted from General Chemistry 1 & 2 , CC BY 4.0 .

Physical Properties

Ether molecules have no hydrogen atom on the oxygen atom (that is, no OH group). Therefore, there is no intermolecular hydrogen bonding between ether molecules. As a result, ethers have quite low boiling points for a given molar mass. In fact, ethers have boiling points about the same as those of alkanes of comparable molar mass and much lower than those of the corresponding alcohols (Table 23.6a.).

Ether molecules do have an oxygen atom, however, and engage in hydrogen bonding with water molecules. Consequently, an ether has about the same solubility in water as the alcohol that is isomeric with it. For example, dimethyl ether and ethanol (both having the molecular formula C₂H₆O) are completely soluble in water, whereas diethyl ether and 1-butanol (both C₄H₁₀O) are barely soluble in water (8 g/100 mL of water).

Spotlight on Everyday Chemistry: General Anesthetics

A general anesthetic acts on the brain to produce unconsciousness and a general insensitivity to feeling or pain. Diethyl ether or ethoxyethane (CH₃CH₂OCH₂CH₃) was the first general anesthetic to be used. Diethyl ether is a colourless, volatile liquid that is highly flammable.

Diethyl ether is relatively safe because there is a fairly wide gap between the dose that produces an effective level of anesthesia and the lethal dose. However, because it is highly flammable and has the added disadvantage of causing nausea, it has been replaced by newer inhalant anesthetics, including the fluorine-containing compounds halothane, enflurane, and isoflurane (Figure 23.6c.). Unfortunately, the safety of these compounds for operating room personnel has been questioned. For example, female operating room workers exposed to halothane suffer a higher rate of miscarriages than women in the general population.

Ethers are produced from alcohols as previously described in this chapter. Figure 23.6d. shows an example of ether production.

around the red H atom in the first molecule, the plus sign, and the red H and O atoms in the second molecule. To the right o the second molecule there is an arrow labeled H subscript 2 S O subscript 4 above and Greek capital delta below. The arrow is labeled, “sulfuric acid.” The resulting molecules are a C atom bonded with three H atoms and a second C atom. The second C atom is bonded to two H atoms and a red O atom. The red O atom has two sets of electron dots. The O atom is bonded to a third C atom which is bonded to two H atoms and a fourth C atom. The fourth C atom is bonded to three H atoms. This molecule is labeled, “diethyl ether.” There is a plus sign and a red H O H." width="1300" height="194" />

Spotlight on Everyday Chemistry: Foxgloves

Foxgloves are poisonous. The large biological molecules contained in the flowers have many ether functional groups. Read more about the chemistry of foxgloves in Infographic 23.6a.

Link to Enhanced Learning

For more support with naming ethers and their properties, see Ether naming and introduction (video) | Khan Academy.

Attribution & References

Except where otherwise noted, this page is written and adapted by David Wegman and Samantha Sullivan Sauer from

• “ 14.8: Ethers ” In Basics of General, Organic, and Biological Chemistry (Ball et al.) by David W. Ball, John W. Hill, and Rhonda J. Scott via LibreTexts, licensed under CC BY-NC-SA 4.0 . / A derivative of Introduction to Chemistry: GOB (v. 1.0),CC BY-NC 3.0
• “18.2 Alcohols and Ethers” In General Chemistry 1 & 2 by Rice University, a derivative of Chemistry (Open Stax) by Paul Flowers, Klaus Theopold, Richard Langley & William R. Robinson and is licensed under CC BY 4.0. ​Access for free at Chemistry (OpenStax)

organic compound with an oxygen atom that is bonded to two carbon atoms

License

Organic and Biochemistry Supplement to Enhanced Introductory College Chemistry Copyright © 2024 by Gregory Anderson; Caryn Fahey; Adrienne Richards; Samantha Sullivan Sauer; David Wegman; and Jen Booth is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.