Carbylamine reaction

Both aliphatic and aromatic PRIMARY amines, when heated together with chloroform (CHCl3) in the presence of a base, give a distinctively foul- or offensive-smelling product, generically called an alkyl or aryl ISOCYANIDE (also called a CARBYLAMINE) -- and this reaction, precisely because it is given ONLY by primary amines, doubles as a genuine chemical TEST specifically for primary amines: secondary and tertiary amines simply do NOT give this test (they lack the N-H hydrogens the mechanism needs). Written as a general equation: R-NH2 + CHCl3 + 3 KOH, heat, gives R-NC (the alkyl/aryl isocyanide) + 3 KCl + 3 H2O -- the base (KOH) here is needed both to gene …