How do I get the chemical equation of aniline to phenylisocyanide?

1 Answer
Mar 2, 2014

The chemical equation is
C₆H₅-NH₂ + 3KOH + CHCl₃ → C₆H₅-NC + 3 KCl + 3H₂O

This is the carbylamine reaction. It is a test for primary amines, because the isocyanide has a foul smell. Secondary and tertiary amines do not give a positive test.

The mechanism involves the formation of dichlorocarbene, :CCl₂.

CHCl₃ + OH⁻ → H₂O + :C⁻Cl₃

:C⁻Cl₃ → :CCl₂ + Cl⁻

R-NH₂ + :CCl₂ → RN⁺H₂-C⁻Cl₂

RN⁺H₂-C⁻Cl₂ + OH⁻→ RNH-C⁻Cl₂ + H₂O

RNH-C⁻Cl₂ + OH⁻→ R-N=C⁻Cl + H₂O + Cl⁻

R-N=C⁻Cl → R-N≡C + Cl⁻

The net ionic equation is

R-NH₂ + CHCl₃ + 3OH⁻ → R-N≡C + 3H₂O + 3Cl⁻