RESUMEN
Hydrophobic nindigo dyes were designed and successfully synthesized from indigo by reacting with substituted anilines in a simple route. Four nindigo dyes were fruitfully analyzed by 1H NMR 13C NMR, electronic and mass spectrometry. Here, we have firstly introduced these nindigo dyes into dyeing area for the dyeing of unmodified polypropylene fiber in aqueous medium. Dyeing experiments has been performed by using didodecyldimethylammonium bromide dispersing agent to make dye-dispersant complex for enhancing the dispersion of dyes. All the dyes were displayed profound blue color hue on polypropylene. The dyeing efficiency and dye fixation order of the nindigo dyes are 3d > 3c ≥ 3b > 3a. Compound 3d having higher the hydrophobic character (logP â 7.04), so greater the dye ability on the polypropylene fiber and exhibiting deep coloration.
