Question

Write down any two methods from preparing phenol. What is the reaction of phenol with
a) Zn b) Br2 water​

Answer 1

Answer:

Preparation of phenol:

(1) From chlorobenzene (Raschig method):

Chlorobenzene is heated with steam at 698 K using calcium phosphate or silica as catalyst. Instead, the reaction can be carried out by using water in presence of copper catalyst at 673 K.

C

6

H

5

−Cl+H

2

O

Ca

3

(PO

4

)

2

698K

C

6

H

5

−OH+HCl

(2) From aniline (Diazotization):

Aniline is diazotized by treatment with nitrous acid (NaNO

2

and HCl) under ice cold conditions to form benzene diazonium chloride. This is followed by hydrolysis with dilute sulphuric acid to form phenol.

C

6

H

5

−NH

2

+HNO

2

+HCl

273-278 K

C

6

H

5

−N

2

+

Cl

−

+2H

2

O

C

6

H

5

−N

2

+

Cl

−

+H

2

O

dil sulphuric acid

C

6

H

5

−OH+N

2

↑+HCl