Question

Name a method for preparing both symmetric and unsymmetrical ethers in the laboratory.

Answer 1

Preparations of ethers by Williamson synthesis:Williamson synthesis is an important method for the preparation of symmetrical and asymmetrical ethers in laboratories.In this method, an alkyl halide is reacted with sodium alkoxide which leads to the formation of ether. The reaction generally follows SN2 mechanism for primary alcohol.
$R-X+R^{\prime }-\stackrel{-}{\underset{..}{\ddot{O}}}\stackrel{+}{Na}\to R-\underset{..}{\ddot{O}}-R^{\prime }+NaX$
As we know alkoxides are strong bases and they can react with alkyl halides leading to elimination reactions. Williamson synthesis exhibits higher productivity in case of primary alkyl halides. In case of secondary alkyl halides, elimination competes with substitution whereas, we observe the formation of elimination product only in case of tertiary alkyl halides.