Synthesis, characterization and sorption studies of B-naphthol azo dyes on wool fabric

A new nano silicagel supported by thionyl chloride as a solid acid was synthesized and used to increase the production yield of dye to affect the efficient diazotization of arylamines. The obtained diazonium salts were then coupled, using standard experimental procedures, in order for to anilines and naphthols to afford the requisite azo dyes in good yield. The diazotization and subsequent azo-coupling generated the related azo dyes at low temperature in short reaction times with no use of dense liquid acids. Structures of the dyes were fully characterized by spectroscopic techniques (UV, IR, 1H and 13C NMR). In addition, the adsorption properties of the synthesized dyes on wool fabric were also determined. The adsorption isotherm was tested by fitting the adsorption data with Langmuir and Freundlich isotherms. The results indicate that the Langmuir model appears to fit the adsorption better than the Freundlich model.