Question

Answer the following

Explain carbylamine reaction with suitable examples.

Answer 1

Carbylamine reaction:

i. Aliphatic or aromatic primary amines on heating with chloroform give foul (offensive) smelling products called alkyl/aryl isocyanides or carbylamines.

ii. This reaction is a test for primary amines. Secondary and tertiary amines do not give this test.

\[\ce{\underset{\text{1° Amine}}{R - NH2} + CHCl3 + 3KOH ->[\Delta] \underset{\text{Alkyl isocyanide}}{R - NC} + 3KCl + 3H2O}\]

e.g.

a.

\[\ce{\underset{\text{Ethylamine}}{CH3 - CH2} - NH2 + \underset{\text{Chloroform}}{CHCl3} + 3KOH->[\Delta] \underset{\text{Ethyl isocyanide}}{C2H5 - NC} + 3KCl + 3H2O}\]

b.

\[\ce{\underset{\text{Aniline}}{C6H5 - NH2} + \underset{\text{Chloroform}}{CHCl3} + 3KOH ->[\Delta] \underset{\text{Phenyl isocyanide}}{C6H5NC} + 3KCl + 3H2O}\]