Question

Write the chemical equation for the preparation of Aniline and write the chemical equation of its reaction with the following:

Hint:

In organic chemistry, the reaction of an amine with chloroform and KOH is a classic test for amines, known as the carbylamine reaction.

Answer 1

Preparation of Aniline:
Aniline can be prepared by reducing nitrobenzene with hydrogen in the presence of a palladium catalyst or using iron and hydrochloric acid: \[ \text{C}_6\text{H}_5\text{NO}_2 + 3\text{H}_2 \xrightarrow{\text{Pd/C}} \text{C}_6\text{H}_5\text{NH}_2 + 2\text{H}_2\text{O} \] Alternatively, it can be prepared from chlorobenzene using a reaction with ammonia under high temperature and pressure: \[ \text{C}_6\text{H}_5\text{Cl} + \text{NH}_3 \xrightarrow{\text{High Temp.}} \text{C}_6\text{H}_5\text{NH}_2 + \text{HCl} \] (A) Reaction with CHCl₃ in presence of KOH:
When aniline reacts with chloroform (CHCl₃) in the presence of potassium hydroxide (KOH), it undergoes a reaction known as the carbylamine reaction, forming an isocyanide (or isocyanide group): \[ \text{C}_6\text{H}_5\text{NH}_2 + \text{CHCl}_3 + \text{KOH} \rightarrow \text{C}_6\text{H}_5\text{NC} + \text{KCl} + \text{H}_2\text{O} \] (B) Reaction with C₂H₅MgBr (Grignard reagent):
Aniline reacts with Grignard reagents like ethylmagnesium bromide (C₂H₅MgBr) to form a secondary amine: \[ \text{C}_6\text{H}_5\text{NH}_2 + \text{C}_2\text{H}_5\text{MgBr} \rightarrow \text{C}_6\text{H}_5\text{NH}(\text{C}_2\text{H}_5) + \text{Mg(OH)Br} \] (C) Reaction with Bromine water:
Aniline reacts with bromine water to form 2,4,6-tribromoaniline: \[ \text{C}_6\text{H}_5\text{NH}_2 + 3\text{Br}_2 + 3\text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_2\text{Br}_3\text{NH}_2 + 3\text{HBr} \] (D) Reaction with NaNO₂ and HCl (273-278 K):
Aniline reacts with sodium nitrite (NaNO₂) and hydrochloric acid (HCl) at low temperatures (273-278 K) to form diazonium salt, which is an important intermediate in many reactions: \[ \text{C}_6\text{H}_5\text{NH}_2 + \text{NaNO}_2 + \text{HCl} \xrightarrow{273-278K} \text{C}_6\text{H}_5\text{N}_2\text{Cl} + \text{NaCl} + \text{H}_2\text{O} \] Final Answer: The preparation of aniline and its reactions with various reagents are shown above. Correct Answer: Chemical equations for each reaction are shown above.