Schiemann_reaction
Balz–Schiemann reaction
Chemical reaction in which an aromatic amine is transformed in aryl fluoride via a diazonium
The Balz–Schiemann reaction (also called the Schiemann reaction) is a chemical reaction in which a primary aromatic amine is transformed to an aryl fluoride via a diazonium tetrafluoroborate intermediate.[1][2][3] This reaction is a traditional route to fluorobenzene and some related derivatives,[4] including 4-fluorobenzoic acid.[5]
The reaction is conceptually similar to the Sandmeyer reaction, which converts diazonium salts to other aryl halides (ArCl, ArBr).[6] However, while the Sandmeyer reaction involves a copper reagent/catalyst and radical intermediates,[7] the thermal decomposition of the diazonium tetrafluoroborate proceeds without a promoter and is believed to generate highly unstable aryl cations (Ar+), which abstract F− from BF4− to give the fluoroarene (ArF), along with boron trifluoride as the byproduct. Also Nitrogen is the by product.