Cleaner reactive dyeing of ramie fiber using ethyl acetate–liquid ammonia medium

Liquid-ammonia (LA) dyeing is a promising, resource-efficient route for cellulosic coloration; however, its industrial adoption is hindered by poor dye exhaustion and fixation. We report an LA–ethyl acetate (EtOAc) co-solvent system for dyeing ramie with Reactive Red 195 that overcomes these bottlenecks. A Taguchi L₉ orthogonal design identified an optimal liquor ratio of 20:1, 30 % (v/v) EtOAc, 8 % o.m.f. of dye, and a 160 s dyeing time, yielding a maximum color strength (K/S) of 19.3. Subsequent fixation in an oil-in-water emulsion increased the fixation efficiency to 89.9 %, while preserving wash, fade, and stain fastness ratings of 4–5. Structural analysis confirmed the coexistence of cellulose I and III, accompanied by an enlarged amorphous fraction, which correlates with enhanced tensile properties. Reactive Red 195 exhibited minimal hydrolysis in the LA–EtOAc medium, enabling complete bath recycling and virtually zero liquid discharge. These findings provide a viable framework for scaling LA-based reactive dyeing with reduced environmental footprint and improved product performance. • A novel sustainable approach was delivered to improve the reactive dye exhaustion on Ramie fiber. • The dyeing performance was significantly accelerated in the presence of EtOAc+LA. • The dyeing parameters were statistically tuned using the well-known Taguchi robust method. • The molecular structure of reactive dye was stable throughout the dyeing process.