Synthesis and efficient dyeing of anthraquinone derivatives on polyester fabric with supercritical carbon dioxide

Two series of anthraquinone dye derivatives [CNU-1 to CNU-7 and CNU-8 to CNU-10] have been successfully synthesized from commercially inexpensive and readily available starting materials by using simple and convenient methods. All synthesized anthraquinone dyes were characterized by 1H NMR, 13C NMR, and UV–Vis spectroscopy and HRMS. The UV–Vis spectra of the dyes indicated that the absorption wavelengths of dyes were approximately 590–655 nm, which indicated that these are blue dyes. Polyester fabrics were dyed with these compounds using supercritical carbon dioxide as a green medium. All the compounds displayed deep color shades and excellent dye fixation even at low concentrations (0.5%). In the fastness experiments, compounds CNU-1 to CNU-10 all exhibited excellent results in washing (4–5), sweat (4–5) and lightfastness [CNU-1 to 7 (4–5), CNU-8 to 10 (2–3)]. Hence, our results revealed that these types of anthraquinone dyes are commercially most acceptable, and they practically exhibited satisfactory color uniformity.