Question

What is the reaction involved when aniline is converted into phenyl isocyanide?

Answer 1

Hint: Aniline is aromatic nitrogen containing organic compounds. It contains a phenyl ring and a $N{{H}_{2}}$ group attached to its carbon – 1. Isocyanide is a functional group containing nitrogen and carbon. The arrangement of carbon and nitrogen in isocyanide is in the order NC$\left( N\equiv C \right)$ . While in cyanide it is CN.

Complete answer:
Aniline is an organic compound containing an amine group. It has a 6- carbon atom ring on which the amine group is attached. It can be converted into phenyl isocyanide by a special reaction called carbylamine reaction, which is also a test for isocyanide.
When aliphatic or aromatic primary$1{}^\circ $amines react with chloroform in the presence of a strong alkali then a foul smelling compound that is isocyanide is formed. This reaction is known as carbylamine reaction.
It can convert aniline into phenyl isocyanide as follows:
$Ph-N{{H}_{2}}+CHC{{l}_{3}}+3KOH\to Ph-NC+3KCl+3{{H}_{2}}O$
Aniline gets converted to phenyl carbylamine or phenyl isocyanide.
Hence, aniline is converted into phenyl isocyanide by carbylamine reaction.

Additional information:
Carbylamine reaction is also called isocyanide test, as it can distinguish primary$1{}^\circ $amine from secondary $2{}^\circ $and tertiary$3{}^\circ $amines. The primary amine will make a foul smelling isocyanide compound with this reaction, so it can be distinguished from secondary and tertiary.

Note:
Amines act as Lewis bases as they have a lone pair of electrons on nitrogen atoms, but aromatic amines are less basic. Isocyanide ion $C{{N}^{-}}$ is an ambident nucleophile, which means it has the ability to attach on the carbon chain either as $\left( N\equiv C \right)$ called as isocyanide or as $\left( C\equiv N \right)$ called as cyanide.