Preparation of Aromatic Nitriles from Aromatic Primary Amines using Tetracyanonickelate (II)

Abstract

The reaction of tetracyanonickelate (II) ion with benzenediazonium chloride, which gives benzonitrile, has been studied in order to disclose the stoichiometric relationship and optimum conditions. The results obtained are summarized as follows.
1) In the presence of sodium carbonate or sodium phosphate, it is possible to use four moles of benzenediazonium salt against one mole of sodium tetracyanonickelate (II). The reaction equation is such as given in the following.
4C₆H₅N₂^⊕·BF₄^_??_+ Na₂ [Ni (CN) ₄] + Na₂CO₃ → 4C₆H₅CN + 4N₂ + 4NaBF₄ + NiCO₃
2) The yield of benzonitrile considerably varies with the pH of the reaction solution. The optimum pH is ca. 10.
3) The reaction is inhibited by free cyanide ion.
Proper conditions thus obtained with benzenediazonium salt have been applied to formation of nitriles from thirteen aromatic diazonium salts.