TY - JOUR
T1 - Binary mixtures of ionic liquids-DMSO as solvents for the dissolution and derivatization of cellulose
T2 - Effects of alkyl and alkoxy side chains
AU - Ferreira, Daniela C.
AU - Oliveira, Mayara L.
AU - Bioni, Thais A.
AU - Nawaz, Haq
AU - King, Alistair W.T.
AU - Kilpeläinen, Ilkka
AU - Hummel, Michael
AU - Sixta, Herbert
AU - El Seoud, Omar A.
N1 - Funding Information:
D. C. Ferreira thanks FIPT for PDCE fellowship for her stay at Aalto University. M. L. Oliveira, T. A. Bioni and H. Nawaz thanks FIPT, Capes, and FAPESP, respectively for their fellowships. O. A. El Seoud thanks CNPq for research productivity fellowships (grant 307022/2014-5 ) and FAPESP for financial support ( 2014/22136-4 ). H. Sixta and M. Hummel wish to thank Tekes – the Finnish Funding Agency for Innovation - and Finnish Bioeconomy Cluster FIBIC Ltd for funding.
Publisher Copyright:
© 2019
PY - 2019/5/15
Y1 - 2019/5/15
N2 - 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 of the imidazolium ring due to intramolecular hydrogen bonding. Using the corresponding ILs with C2–CH 3 instead of C2–H, 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.
AB - 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 of the imidazolium ring due to intramolecular hydrogen bonding. Using the corresponding ILs with C2–CH 3 instead of C2–H, 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.
KW - Biopolymer derivatization
KW - Cellulose dissolution
KW - Cellulose esters
KW - Ionic liquid-DMSO
KW - Solvatochromism
UR - http://www.scopus.com/inward/record.url?scp=85061769510&partnerID=8YFLogxK
U2 - 10.1016/j.carbpol.2019.02.024
DO - 10.1016/j.carbpol.2019.02.024
M3 - Article
C2 - 30832848
AN - SCOPUS:85061769510
SN - 0144-8617
VL - 212
SP - 206
EP - 214
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
ER -