Synthesis and properties of acid dyes derived from 7-amino-1hydroxynaphthalene-3-sulphonic acid

The paper concerns the synthesis of red acid dyes derived from gamma-acid and containing one sulphonamide group in the dye molecule. These dyes are designed for dyeing polyamide and wool fibres from weakly acidic dyebaths. The dyes were examined in respect of their application, fastness and spectroscopic characteristics. It was found that the sulphonamide group and substituents present at its nitrogen atom influenced the properties of these dyes.