Hsu, Hui-WenHui-WenHsuSHIH-HUANG TUNGRU-JONG JENG2026-02-052026-02-052025-12https://www.scopus.com/record/display.uri?eid=2-s2.0-105025676028&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/735814Ionic liquids (ILs) are promising sustainable solvents for cellulose processing owing to their high solubility, thermal stability, and recyclability. However, conventional imidazolium-based ILs, such as 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), are prone to C2-position side reactions and exhibit limited recyclability, which significantly constrains their industrial applicability. This study introduces a viable IL, 1-isopropyl-3-methylimidazolium dimethylphosphate ([iPMIM]DMP), featuring dual innovation: a branched isopropyl cation that enhances cellulose solubility through steric effects, and a low-pKa dimethylphosphate anion that suppresses side reactions and improves recyclability. Synthesized via a simple one-step route, [iPMIM]DMP exhibits excellent thermal stability, high cellulose solubility, and favorable rheological properties suitable for dry-jet wet spinning. Regenerated fibers prepared from paper-grade pulp show a tenacity of 36.90 cN/tex, comparable to industrial N-methylmorpholine N-oxide (NMMO)-based fibers. Moreover, [iPMIM]DMP can be efficiently recovered and reused over three dissolution–spinning cycles without performance loss, demonstrating strong chemical robustness. This work provides a practical and sustainable approach for recyclable ILs in cellulose fiber production.falseDialkylimidazolium dimethylphosphateDry-jet wet spinningIonic liquid (IL)RecyclingRegenerated cellulose filamentjournal article10.1016/j.scp.2025.1022672-s2.0-105025676028