Alcohol, Phenols and Ethers

Williamson ether synthesis An $\mathrm{S}_{\mathrm{N}} 2$ reaction between an alkoxide and an alkyl halide. Williamson synthesis work best with $2^{\circ}$ and $3^{\circ}$. If often gives E2 elimination product.

In o-nitrophenol, hydrogen of $ \mathrm{O}-\mathrm{H} $ group and oxygen of nitro group form intramolecular hydrogen bonding producing a six membered ring structure while in $ m $-nitrophenol, $ p $-nitrophenol and phenol, intermolecular hydrogen bonding are present.

The structure is,

Cyclohexanol on reaction with H₂SO₄ and heating gives cyclohexene as follows

Methyl alcohol can be distinguished from ethyl alcohol by iodoform test as follows by using sodium hydroxide and iodine.

${C_2}{H_5}OH\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Iodoform\,test}^{NaOH/{I_2}}} CH{I_3}$ (yellow ppt.)

$C{H_3}OH\buildrel {NaOH/{I_2}} \over \longrightarrow $ No. ppt.

Phenol on reaction with chloroform an KOH gives salicylaldehyde, which with 50% KOH solution undergoes Cannizzaro's reaction.