Binary mixtures of ionic liquids-DMSO as solvents for the dissolution and derivatization of cellulose: Effects of alkyl and alkoxy side chains

Author(s)

Ferreira, Daniela C. ^{[1, 2]} ; Oliveira, Mayara L. ^[1] ; Bioni, Thais A. ^[1] ; Nawaz, Haq ^[1] ; King, Alistair W. T. ^[3] ; Kilpelainen, Ilkka ^[3] ; Hummel, Michael ^[4] ; Sixta, Herbert ^[4] ; El Seoud, Omar A. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Chem, Prof Lineu Prestos Av 748, BR-05508000 Sao Paulo, SP - Brazil

^[2] Inst Technol Res State Sao Paulo, Prof Almeida Prado Av 532, BR-05508901 Sao Paulo, SP - Brazil

^[3] Univ Helsinki AI Virtasen Aukio 1, Dept Chem, POB 55, Helsinki 00014 - Finland

^[4] Aalto Univ, Sch Chem Engn, Dept Bioprod & Biosyst, POB 16300, FI-00076 Aalto - Finland

• Document type: Journal article
• Source: Carbohydrate Polymers; v. 212, p. 206-214, MAY 15 2019.
• Web of Science Citations: 4

Abstract

The efficiency of mixtures of ionic liquids (ILs) and molecular solvents in cellulose dissolution and derivatization depends on the structures of both components. We investigated the ILs 1-(1-butyl)-3-methylimidazolium acetate (C(4)MeImAc) and 1-(2-methoxyethyl)-3-methylimidazolium acetate (C(3)OMeImAc) and their solutions in dimethyl sulfoxide, DMSO, to assess the effect of presence of an ether linkage in the IL side-chain. Surprisingly, C(4)MeImAc-DMSO was more efficient than C(3)OMeImAc-DMSO for the dissolution and acylation of cellulose. We investigated both solvents using rheology, NMR spectroscopy, and solvatochromism. Mixtures of C(3)OMeImAc-DMSO are more viscous, less basic, and form weaker hydrogen bonds with cellobiose than C(4)MeImAc-DMSO. We attribute the lower efficiency of C(3)OMeImAc to ``deactivation{''} of the ether oxygen and C2-(H) under bar of the imidazolium ring due to intramolecular hydrogen bonding. Using the corresponding ILs with C2-(CH3) under bar instead of C2-(H) under bar, namely, 1-butyl-2,3-dimethylimidazolium acetate (C(4)Me(2)ImAc) and 1-(2-methoxyethyl)-2,3-dimethylimidazolium acetate (C(3)OMe(2)ImAc) increased the concentration of dissolved cellulose; without noticeable effect on biopolymer reactivity. (AU)

• FAPESP's process: 14/22136-4 - Use of green solvents and their mixtures for optimizing chemical processes
• Grantee: Omar Abou El Seoud
• Support Opportunities: Research Projects - Thematic Grants