Question

Give the equations of reactions for the preparation of: (any three) (a) Phenol from chlorobenzene
(b) Salicyaldehyde from phenol
(c) 2-Methoxyacetophenone from anisole

Hint:

- Phenol preparation via Wurtz-Fittig reaction involves nucleophilic substitution and hydrolysis. - Salicyaldehyde is obtained by the haloform reaction, a method of introducing an aldehyde group. - Acetylation of anisole forms 2-methoxyacetophenone through electrophilic substitution with acetyl chloride. - Nitration of phenol using conc. HNO\(_3\) introduces nitro groups and leads to picric acid.

Answer 1

(a)
The Wurtz-Fittig reaction is employed. Chlorobenzene (C\(_6\)H\(_5\)Cl) undergoes nucleophilic substitution with NaOH at high temperature and pressure (623K, 300 atm), followed by acidic hydrolysis, yielding phenol.

(b) Salicylaldehyde from phenol

(b) Phenol (C\(_6\)H\(_5\)OH) undergoes the haloform reaction with CHCl\(_3\) and NaOH, producing a salicylic acid intermediate. Acid hydrolysis then yields salicylaldehyde.

(c)
Anisole (C\(_6\)H\(_5\)OCH\(_3\)) reacts with acetyl chloride (CH\(_3\)COCl) in the presence of anhydrous AlCl\(_3\) to produce 2-methoxyacetophenone.

(d) Picric acid from phenol
Phenol is nitrated with concentrated nitric acid (HNO\(_3\)) to yield picric acid (2,4,6-trinitrophenol).