Reactions of Ethers
Involving the Alkyl Group

On this page we will learn two important reactions that involve the alkyl group of ether.

  1. Formation of peroxides
  2. Halogenation

Formation of peroxide

Ethers are oxidised to peroxides when exposed to air and light.

Peroxide effect in ether

These peroxides are very dangerous and cause explosion on heating. Hence, the presence of peroxide should be tested and removed before use.

Test for the presence of peroxides

Ether samples are shaken with aqueous KI. Appearance of purple or brownish colour indicates the presence of peroxide.


The reaction of ether with halogens is known as halogenation of ether. The products we get when ethers react with halogens largely depend on the condition.

For example, we get α,α'-dichlorodiethyl ether when diethyl ether reacts with Cl2 in dark.

Reaction of diethyl ether with Cl2 in dark yields alpha-alpha'-dichlorodiethyl ether

In presence of light and excess of chlorine, all the hydrogen atoms are replaced by chlorine.

Reaction of diethyl ether with Cl2 in light yields perchlorodiethyl ether