Dissolution of cellulose in imidazolium-based double salt ionic liquids

M Mahbubur Rahman; M Sarwar Jahan; Md Mominul Islam; Md Abu Bin Hasan Susan

doi:10.1016/j.ijbiomac.2024.131331

Dissolution of cellulose in imidazolium-based double salt ionic liquids

Int J Biol Macromol. 2024 Apr 3;267(Pt 1):131331. doi: 10.1016/j.ijbiomac.2024.131331. Online ahead of print.

Authors

M Mahbubur Rahman¹, M Sarwar Jahan², Md Mominul Islam³, Md Abu Bin Hasan Susan⁴

Affiliations

¹ Bangladesh Council of Scientific and Industrial Research, Dr. Qudrat-i-Khuda Road, Dhaka 1205, Bangladesh; Department of Chemistry, University of Dhaka, Dhaka 1000, Bangladesh.
² Bangladesh Council of Scientific and Industrial Research, Dr. Qudrat-i-Khuda Road, Dhaka 1205, Bangladesh.
³ Department of Chemistry, University of Dhaka, Dhaka 1000, Bangladesh.
⁴ Department of Chemistry, University of Dhaka, Dhaka 1000, Bangladesh; Dhaka University Nanotechnology Center (DUNC), University of Dhaka, Dhaka 1000, Bangladesh. Electronic address: susan@du.ac.bd.

PMID: 38574918
DOI: 10.1016/j.ijbiomac.2024.131331

Abstract

The dissolution of cellulose in double salt ionic liquids (DSILs) was studied in detail and compared with the dissolution in individual constituent ionic liquids (ILs). The DSILs, [C₄mim](CH₃CO₂)_xCl_1-x (x is the mole fraction of the single component ILs), were synthesized using acetate and chloride salts of 1-butyl-3-methylimidazolium. These DSILs were then used for the investigation of the solubility of cellulose in the whole mole fraction range. Commercial cellulose (CC) powder, kraft pulp (KP), and prehydrolysis kraft pulp (PHKP) of jute were chosen as cellulose sources. The solubility of cellulose increased with an increasing temperature for [C₄mim](CH₃CO₂)_0.6Cl_0.4 and with increasing amount of [C₄mim]Cl in DSILs. The maximum solubility of CC powder was 32.8 wt% in [C₄mim](CH₃CO₂)_0.6Cl_0.4 at 100 °C, while for KP and PHKP, solubilities were 30.1 and 30.5 wt%, respectively under the identical condition. Cellulose could be regenerated from the DSILs using water as an antisolvent. Structure, morphology, and thermal stability of the regenerated cellulosic materials were analyzed. DSILs could be recycled >99 % without a discernible change in structure. This work demonstrates that DSILs display enhanced solubility over ILs system and have potential as a chemical processing methodology.

Keywords: Dissolution of cellulose; Double salt ionic liquids; Recycle and reuse.