Question

How will you convert chlorobenzene into the following? (Write chemical equations only) (i) Benzene
(ii) Phenol
(iii) Toluene
(iv) Aniline
(v) Diphenyl

Hint:

Remember: Hydrolysis gives phenol, reduction gives benzene, Friedel–Crafts gives toluene, ammonolysis gives aniline, and Ullmann reaction gives diphenyl.

Answer 1

(i) Chlorobenzene to Benzene:
By reduction with Ni/Alkali.
\[ C_6H_5Cl + 2[H] \; \xrightarrow{Ni/NaOH} \; C_6H_6 + HCl \] (ii) Chlorobenzene to Phenol:
By hydrolysis under high temperature and pressure.
\[ C_6H_5Cl + NaOH \; \xrightarrow{623K, \; 300 atm} \; C_6H_5OH + NaCl \] (iii) Chlorobenzene to Toluene:
Through Friedel–Crafts alkylation.
\[ C_6H_5Cl + CH_3Cl \; \xrightarrow{AlCl_3} \; C_6H_5CH_3 + HCl \] (iv) Chlorobenzene to Aniline:
Via nitration followed by reduction.
\[ C_6H_5Cl \; \xrightarrow{HNO_3/H_2SO_4} \; o\!-\!& \!p\!-\!ClC_6H_4NO_2 \] \[ ClC_6H_4NO_2 \; \xrightarrow{Sn/HCl} \; ClC_6H_4NH_2 \] Then by Sandmeyer reaction: \[ C_6H_5Cl \; \xrightarrow{NH_3/Cu_2O} \; C_6H_5NH_2 \] (v) Chlorobenzene to Diphenyl:
Through Ullmann reaction.
\[ 2C_6H_5Cl + 2Na \; \xrightarrow{Cu, \; \Delta} \; C_6H_5\!-\!C_6H_5 + 2NaCl \] Conclusion:
Chlorobenzene undergoes reduction, hydrolysis, substitution, or coupling reactions under suitable conditions to give benzene, phenol, toluene, aniline, and diphenyl.