This study aims to explore a rapid, less expensive, clean and environmentally friendly approach to the synthesis of disperse dyes based on 4-substituted benzenesulfonamide derivatives and evaluate their uses as colorants for dying and printing on polyester fabric.
The disperse dyes were created by dissolving solution of the diazonium salt of a 4-substituted benzenesulfonamide derivative 1 reaction with N’-(2-bromobenzylidene)-2-cyanoacetohydrazide in 25 mL of ethanol was added to the diazonium salt. The reaction mixture was then stirred in an ice bath for 2 h. Thus, developing less hazardous synthetic methods for organic reactions is one of the objectives in current research. The chemical structure of the produced dye was studied using elemental analysis, Fourier-transform infrared spectroscopy, 1H NMR and 13C NMR spectroscopic analytical methods. Quantum chemical calculations were performed using the time-dependent density function theory (TD-DFT)-B3LYP method and a 6-311G(d) basis set.
By varying the dyeing parameters, such as pH (2–8), shade (2–6%), duration (10–30 min) and temperature (100–130 °C), a comparative examination of various colorimetric and color strength (K/S) properties of polyester fabric dye using two new dispersion dyes was carried out. Higher K/S ratios were attained by polyester fabrics treated with dispersed dyes after longer dyeing times) and higher temperatures. The resulting hues were reddish-brown, yellowish-brown, beige and dark brown. According to TD-DFT calculation, dye 2 exhibits more energy changes than dye 3, indicating strong binding interactions. However, because of its higher hardness and electronegativity, dye 3 is more stable. In contrast to dye 3, dye 2 exhibits increased reactivity due to its greater softness and lesser hardness. These variations draw attention to the unique qualities of the two colors. It was also noticed that dye 2 is more efficient than dye 3 in the printing ink characterization according to their results based on lightfastness, washing, alkali respiration and crock fastness.
The produced disperse dyes (2 and 3) have the potential to be promising colorants in a variety of applications, such as coloring and printing. Synthetic dyes are often a great choice for printing and dyeing polyester textiles. They also provide a workable way to provide polyester textiles with a range of hues.
