Arylene Azo p-Hydroxy Benzoic Acid–Formaldehyde Oligomer Dyes

A series of oligomeric azo dyes has been synthesized by coupling various aromatic diazonium salts to p-hydroxy benzoic acid–formaldehyde ( p-HBAF) oligomer. They were evaluated in terms of their softening points, yields, colour, UV–visible spectra, IR spectra and PMR spectra. Dyeing on wool and nylon resulted in yellow to red shades having moderate to good fastness to light and good to very good fastness to washing.