Disperse-reactive dyes for sustainable waterless textile dyeing: current status, challenges, and future perspectives.

Disperse-Reactive (DR) dyes represent a promising class of hybrid colorants that combine the hydrophobic characteristics of disperse dyes with reactive functional groups, offering a potential solution for sustainable dyeing of polyester/cotton blends. This review critically evaluates the reported experimental validation and theoretical potential of DR dyes across five waterless or low-water coloration platforms: supercritical carbon dioxide (SC-CO2), inkjet digital printing, solvent-assisted systems, reverse micelle methods, and ionic liquid/deep eutectic solvent (ILs/DES) systems. While SC-CO2 dyeing has been the most extensively investigated platform, with over twenty published studies demonstrating the application of various DR dyes on cotton, polyester, silk, wool, nylon, and blended fabrics, other platforms remain largely unexplored. Solvent-assisted dyeing using decamethylcyclopentasiloxane (D5) has shown preliminary promise in a single study, whereas inkjet digital printing and reverse micelle methods have only one and zero experimental reports, respectively. Notably, no experimental study has yet employed DR dyes in ILs/DES media, and their application in this context remains purely conceptual. Our comparative analysis indicates that Inkjet digital printing is mature for standard inks, but its application with DR dyes is at an early stage and the maturity of DR formulations is not established. SC-CO2 holds long-term potential, but its superiority is not established. This review identifies critical research gaps, particularly the absence of experimental studies in IL/DES and reverse micelle systems and limited validation in inkjet-related systems, and outlines a roadmap for future molecular engineering of DR dyes including optimized reactive groups, enhanced solubility in non-aqueous media, and improved fixation efficiency to bridge the gap between conceptual promise and practical industrial implementation. Collectively, these findings position DR dyes as an emerging and promising, yet experimentally under-validated, enabling chemistry for next-generation sustainable textile coloration.