Ethers

Ether is the anhydride of alcohol. R – O – R'

General molecular formula of ether: CnH2n+2O 

Ethers are classified into two types based on the nature of alkyl groups:

  1. Symmetrical ethers (or) simple ethers: R = R', so R – O – R
  2. Unsymmetrical ethers (or) mixed ethers:  R ≠ R', so R – O – R'

Isomerism by Ethers

Ethers will exhibit metamerism, functional isomerism and chain isomerism.

Diethyl ether (sulphuric ether)

Preparation

1. Dehydration

a) By the dehydration of ethyl alcohol in the presence of conc. H2SO4 at 140°C.

b) By the dehydration of ethyl alcohol in presence of anhydrous alumina at 250°C.

2. From ethyl chloride: By the reaction of ethyl chloride with dry silver oxide.

3. Williamson’s synthesis: Alkyl halides react with sodium alkoxides to produce ethers. This method is suitable for the preparation of both simple and mixed ethers. 

Chemical Reactions

Ethers are chemically inert because O is flanked in between two bulky alkyl groups. Therefore, ethers are not easily oxidisable and they will not decolourise permanganate or dichromate.