Application of modified clays in diazotization and azo coupling reactions in water

Diazotization and diazo coupling reaction of a series of aromatic amines and activated aromatic compounds over eco-friendly modified clay catalysts are described. The reaction was catalyzed by modified montmorillonite K-10 including Cu2+, Fe3+, and Zn2+ metal ions. The versatility of this method was checked by using various amines and phenols, which showed reasonable yields of products. These inexpensive, noncorrosive and reusable catalysts were found to exhibit bifunctional catalytic properties for diazotization and diazo coupling reactions. The catalysts could be reused several times without significant loss of their catalytic reactivity.