Synthesis of azo disperse dyes containing pyridine ring for dyeing polyester and polyacrylic fibres

Abstract

Purpose – The purpose of this paper is to discuss the synthesis of new azo disperse dyes containing pyridine ring for dyeing acetate polyester and other fibres. Design/methodology/approach – Cycloaddition reaction of 3-formylchromone (Compound 1) with ethyl vinyl ether (Compound 2) afforded 3-ethoxy-4,4a-dihyro-3H,10H-pyrano[4,3-b]chromen-10-one (Compound 3). Reaction of 3 with aqueous ammonium sulphite in ethanol furnishes 3-(2-hydroxybenzoyl)pyridine (Compound 5). Compound 5 was fully characterised by spectroscopic techniques. Ten arylazo derivatives of Compound 6 have been prepared for use as dyestuffs. The effect of the nature and orientation of substituents in the diazonium component on the colour of azo dyes is discussed. Dyeing performance of the dyes on different fibres has also been assessed. Findings – Most of the dyes showed good affinity to polyester fibres. On the other hand, polyacrylic fibres were only stained to weak shades. Originality/value – No details regarding the synthesis and dyeing performance of such dyes are reported before in the literature.