Synthesis and investigation of dyeing properties of 8-hydroxyquinoline-based azo dyes

A facile and well-known synthetic strategy has been used to prepare two novel 8-hydroxyquinoline-based azo dyes to apply as a disperse dye to polyester fabric. In this method, 8-hydroxyquinoline possessing a “privileged structure” which is made up of two rings, a phenol ring fused with pyridine ring, has been coupled with diazonium salt obtained from 2-amino-6-nitrotoluene (Dye-I) and with the diazonium salt obtained from 4-chloro-aniline (Dye-II). The structure of the dyes has been confirmed using nuclear magnetic resonance spectroscopy, Fourier-transform infrared spectroscopy, and elemental analysis. As-synthesized dyes are used as disperse to polyester fabric, and the dyed samples were characterized for color fastness to washing, light, rubbing, and perspiration. The fastness testing results indicate that the dyes have a good affinity to PET fabric as the dyed PET fabrics have moderate to excellent fastness to washing and light and very good fastness to rubbing and perspiration. The dyeing property of 8-hydroxyquinoline-based dyes is very promising and can be considered as the potential candidate to meet the actual demand of PET fabric dyeing in the textile industry.