7.2 Reactions in which Nitrogen Eliminated

7.2.1 Replacement by Hydroxyl

Diazonium salt on warming in water gives phenol via SN₁ mechanism. The reaction is generally performed in acidic solution to preserve phenol in its unionized form.

7.2.2 Replacement by Halogen

7.2.2.1 Schiemann Reaction

Treatment of an aqueous solution of diazonium salt with fluoroboric acid under cold conditions gives diazonium fluoroborate as precipitate, which could be dried and gently heated to afford the flurobenzene by decomposition. The reaction involves SN₁ mechanism.