Question

The yield of chlorobenzene obtained by reaction of phenols with $P{Cl}_5$ is less, due to the formation of :

• A. o-chlorophenol
• B. p-chlorophenol
• C. phosphorus oxychloride
• D. triphenyl phosphate

Answer 1

The correct option is D triphenyl phosphate

The $(-OH)$ group on phenol unlike that of alcohol, is difficult to replace by a halogen, e.g., halogen acids have no action, and $P{X}_3$ yields only phosphorous esters.

Phenol reacts with $P{Cl}_5$ or $P{Br}_5$, when the $(-OH)$ group of phenol is replaced by a halogen atom. The yield of chloro or bromo benzene is small the main product is triphenyl phosphate ${\left(PhO\right)}_{3}P=O$ or ${Ph}_3{PO}_4$.

Phenol further reacts with $PO{Cl}_3$ to give ${Ph}_3{PO}_4$.

Option D is correct.