Synthesis of Azo Dyes Based on Naphthols, Xanthines, and Hydroxy Coumarins in the Presence of Cellulose Sulfonic Acid

This study used cellulosulfonic acid as a new catalyst for synthesizing azo dyes based on naphthol, xanthene, and hydroxycoumarin. Also, cellulosulfonic acid catalyst was recyclable and was used in five steps. The structure of the synthesized compounds was determined by comparing their physical properties with previously reported values using IR and HNMR spectroscopy data. The results showed that these synthetic reactions are elementary and produce azo dyes with good efficiencies. The advantages of the proposed method are the avoidance of environmentally harmful solvents, mild conditions, high speed and short reaction time, simplicity of working up process, high efficiency, and purity of synthesized derivatives.