Chinese Journal of Applied Chemistry ›› 2018, Vol. 35 ›› Issue (4): 449-456.DOI: 10.11944/j.issn.1000-0518.2018.04.170108

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Dissolution of Cellulose in Carboxylate-Based Task-Specific Ionic Liquids

Hao MA,Chunyan LIAO,Meilin FAN,Xue'en LIU,Junjiang TENG(),Ning LI   

  1. College of Chemical Engineering,Guangdong University of Petrochemical Technology,Maoming,Guangdong 525000,China
  • Accepted:2014-08-08 Published:2018-03-30 Online:2018-04-02
  • Contact: Junjiang TENG
  • Supported by:
    Supported by the Talent Introduction Program of Guangdong University of Petrochemical Technology(No.2016rc06), the Ordinary University Innovation Project of Guangdong Province, China(No.2015KTSCX091), the Students Innovation and Entrepreneurship Training Program of Guangdong University of Petrochemical Technology(No.2016pyA006)

Abstract:

Carboxylate-based task-specific ionic liquids(ILs), viz., 1,3-dimethylimidazolium acetate([C1mim][CH3COO]) and 1,3-dimethylimidazolium hydroxylcarboxylate([C1mim][HOCH2COO]), have been synthesized, and used as the solvents for cellulose dissolution. The results show that the structure of anions has a significant influence on cellulose dissolution; and at 120 ℃, the solubility of cellulose in [C1mim][CH3COO] and [C1mim][HOCH2COO] can reach up to 19.7% and 21.2%, respectively. The structure and thermal stability of pristine and regenerated celluloses were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction(XRD), and thermogravimetry analysis(TGA) methods. These results demonstrate that the two ionic liquids are the direct solvent for cellulose, and also indicate that the transformation from cellulose I to amorphous cellulose occurrs after the dissolution and regeneration processes in ionic liquids. Moreover, further analysis on the degree of polymerization(DP) of regenerated cellulose shows that the dissolution temperature and time have the negative effect on cellulose DP; and higher dissolution temperature or longer dissolution time affords the lower DP of regenerated cellulose. These results may serve as guidance for developing new cellulose solvent systems in the future.

Key words: ionic liquid, cellulose, carboxylate, dissolution, regeneration