Nano Silica Phosphoric Acid: A Highly Efficient 3 and Heterogeneous catalyst for Synthesis of Azo Dyes Based 4 on 1- and 2-Naphthol at Room Temperature

چکیده مقاله

Diazotization of aromatic amines with sodium 10 nitrite, nano silica phosphoric acid (nano-SPA) at room 11 temperature and diazo coupling with 1- or 2-naphthol has developed a mild and convenient method for the synthesis of azo dyes. The properties of SPA nano parti- 12 cles was characterized by scanning electron microscope, 13 transmission electron microscope and X-ray diffraction, 14 and the structure of final azo compounds was verified by 15 FT-IR and 1H NMR. The ensuing aryl diazonium salts 16 supported on nano-SPA, were sufficiently stable to be kept 17 at room temperature in the dry state.