Question

Anisole on reaction with HI produces only phenol and methyl iodide. Give reason?

Answer 1

Phenyl methyl ether or anisole $\left({\mathrm{CH}}_3{\mathrm{OC}}_6{\mathrm{H}}_5\right)$ reacts with Hydrogen iodide (HI) to give phenol and Methyl iodide $\left({\mathrm{CH}}_3\mathrm{I}\right)$

• Hydrogen iodide $\left(\mathrm{HI}\right)$ consists of a proton $\left({\mathrm{H}}^{+}\right)$and Iodide ion $\left({\mathrm{I}}^{-}\right)$.

Reaction mechanism:

Step-1: Acceptance of proton by Oxygen

As oxygen is electronegative, it will accept the proton resulting in a positive charge on oxygen.

Step-2: Cleavage of bond

There are two possibilities of bond cleavage.

• O and C bond of Phenyl group
• O and C bond of Methyl group

O and C bond of Phenyl group has double bond character due to resonance with the phenyl group.

Due to the double bond character the O and C bond has more strength and difficult to cleave. So O and C bond of methyl group cleaves and phenol and methyl iodide is formed.