Methods of Preparation - From Hydrocarbons (II)

Description:

Sandmeyer’s Reaction

The reaction involves two steps −

• Formation of diazonium salt.
• Reaction of diazonium salt with Cu₂X₂ (X = Cl, Br)

Diazonium salt is prepared by reacting a primary aromatic amine with sodium nitrite in cold mineral acid.

Mechanism − NaNO₂ + HCl → HNO₂ + NaCl

Diazonium salt freshly prepared now reacts with cuprous halide to give corresponding aryl halide.

Note − Aryl iodide can be obtained directly by shaking diazonium salt with KI.