Synthesis
Diazotization of aniline: : C6H5NH2 + HNO2 (from NaNO2 and HCl) + HCl → 6H5N2">6H5N2l + 2 H2O The tetrafluoroborate can be obtained from crude benzenediazonium chloride by salt metathesis using tetrafluoroboric acid. : 6H5N2">6H5N2l + HBF4 → 6H5N2">6H5N2F4 + HCl The tetrafluoroborate is more stable than the chloride.Properties
The diazo group (N2) can be replaced by many other groups, usually anions, giving a variety of substituted phenyl derivatives: :C6H5N2+ + Nu− → C6H5Nu + N2 These transformations are associated with many named reactions including the Schiemann reaction, Sandmeyer reaction, and Gomberg–Bachmann reaction. A wide range of groups that can be used to replace N2 including halide, SH−, CO2H−, OH−. Of considerable practical value in the dye industry are the diazo coupling reactions. Reaction with aniline gives 1,3-diphenyltriazene. The structure of the salt has been verified bySafety
Whereas the chloride salt is explosive, the tetrafluoroborate is readily isolated.References
{{Reflist Diazo compounds Tetrafluoroborates Phenyl compounds