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.
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
KW - OXIDATION
KW - AQUEOUS-SOLUTIONS
KW - ACETYLATION
KW - ACYLATION
KW - SOLVATOCHROMISM
KW - ACID ANHYDRIDE MIXTURES
KW - MICROWAVE-ASSISTED DERIVATIZATION
KW - DEPENDENCE
KW - DIMETHYL-SULFOXIDE
KW - CELLOBIOSE
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
AN - SCOPUS:85061769510
VL - 212
SP - 206
EP - 214
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
SN - 0144-8617
ER -