Environmentally green approach to synthesize azo dyes based on 1-naphthol using nano BF3·SiO2 under solvent-free conditions

摘要

A series of azo dyes were efficiently synthesized by mixing aromatic amines and NaNO2 in the presence of nano silica supported boron trifluoride (nano BF3·SiO2) and then diazo coupling with 1-naphthol under solvent-free conditions at room temperature. The present methodology has proven to be simple, rapid, environmentally benign, green, and cost-effective compared with previous synthetic methods. Also, by using this procedure, aryl diazonium salts supported on nano BF3·SiO2 were very stable to be kept at room temperature for several months without any special conditions.