Question

Write a note on Williamson’s synthesis. 

OR 

How are ethers prepared from Alkyl halides? 

OR 

How are simple ethers and mixed ethers prepared by Williamson’s synthesis?

Answer 1

Williamson’s synthesis : 

When an alkyl halide (R – X) is heated with sodium alkoxide (R – O – Na), an ether is obtained, this reaction is known as Williamson’s synthesis. 

This method is used to prepare simple (or symmetrical) ethers and mixed (unsymmetrical) ethers.

Sodium alkoxide is obtained by a reaction of sodium with an alcohol.

(A) Simple (Symmetrical) ether : 

When an alkyl halide and sodium alkoxide having similar alkyl groups are heated, symmetrical ether is obtained.

Sodium ethoxide on heating with ethyl bromide gives diethyl ether.

(B) Mixed (Unsymmetrical) ether : 

When an alkyl halide and sodium alkoxide or sodium phenoxide having different alkyl groups are heated, unsymmetrical ether (dialkyl ethers or alkyl aryl ether) is obtained.

Sodium ethoxide on heating with methyl bromide gives ethyl methyl ether.

Sodium phenoxide on heating with ethyl bromide gives ethyl phenyl ether.