Arendiazonium salts are important intermediaries in the substituted aromatic compound synthesis due to the possibility of replacing the diazo group (N2+) by a substitution reaction.
Also these salts can undergo coupling reaction with aromatic activated nuclei to produce azocompoun of shining colours. These compounds are very useful in dye and pigments industry and those derivate from b-naphthol has been widely used in the generation of nanocircuits and data storage processes.
Generally, the synthesis of these salts involves acid medium and is associated with large volumes of hazardous and colored aqueous waste. The release of this sewage in natural environments is very problematic to aquatic life and mutagenic to human, and end of pipe treatments techniques don?t provide a complete solution to the problem.
A synthetic alternative to obtain nitrogen dioxide is the use of different metallic nitrates in presence with halogenides.