Alkali-stable solid state fluorescent pyrazolo/pyrrolinone disperse dyes: Synthesis and application for dyeing polyester fabric

Six novel fluorescent disperse dyes were synthesized by diazo-coupling reaction. As dye intermediates, two diazo components having 5-amino-4-arylazo-3-methyl-1H-pyrazoles moieties were initially prepared, diazotized and coupled with three pyrrolinone esters (PES) derivatives to give azo-hydrazone pyrazolo/pyrrolinone derivatives. The dye structures were confirmed by FTIR, (HNMR)-H-1, mass spectroscopy and elemental analysis. The absorption spectra of the prepared dyes and its solvatochromic behavior were investigated. These dyes displayed significant emission spectra in polycrystalline (powder) form, but no fluorescence observed in solution. The dyes were applied on polyester fabric using conventional high temperature exhaustion dyeing method, exhibited high tinctorial strength and bright fluorescent orange to reddish violet colors on polyester fabric with dyeing stability under acidic, neutral and alkaline pH. The relationship among different dyeing pH and color difference effects for dyed fabrics were studied. It was found that disperse dyes containing phenylazo-pyrazolone structure showed better dyeing performance and alkali-stable dyeing properties on polyester fabrics than those containing nitrophenol derivatives. The color fastness to washing, perspiration, sublimation and light fastness were also investigated. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, six novel fluorescent disperse dyes were synthesized and their absorption spectra, dyeing performance, and color fastness were investigated. It was found that dyes containing phenylazo-pyrazolone structure showed better dyeing performance and dyeing stability on polyester fabrics.