Assessing cellulose dissolution efficiency in solvent systems based on a robust experimental quantification protocol and enthalpy data.
In: Holzforschung: International Journal of the Biology, Chemistry, Physics, & Technology of Wood, Jg. 73 (2019-12-01), Heft 12, S. 1103-1112
academicJournal
Zugriff:
Dissolution of microcrystalline cellulose (MCC) in pure ionic liquids (ILs) and IL/dimethyl sulfoxide (DMSO) mixtures (mole fraction χDMSO = 0.2–0.9) was quantified using a specially constructed mechanical stirring system that allows reproducible agitation speed; temperature control, and minimum solution-air contact. The electrolytes employed were: 1-(n-butyl)-3-methylimidazolium acetate (C4MeIm AcO), 1-(methoxyethyl)-3-methylimidazolium acetate (C3OMeIm AcO), 1,8-diazabicyclo[5.4.0]undec-7-enium acetate (DBU AcO), tetramethylguanidinium acetate (TMG AcO), and tetra(n-butyl)ammonium fluoride hydrate (TBAF·xH2O). The effects on MCC dissolution of IL/DMSO composition, and temperature (50, 70°C) were studied. C4MeIm AcO and C4MeIm AcO/DMSO were more efficient solvents than their C3OMeIm AcO counterparts, due to "deactivation" of the ether oxygen of C3OMeIm AcO. MCC dissolution by C4MeIm AcO/DMSO was compared with DBU AcO/DMSO, TMG AcO/DMSO at χDMSO = 0.6, and TBAF·xH2O/DMSO at χDMSO = 0.95. The relative efficiency was (solutions in DMSO): C4MeIm AcO > C3OMeIm AcO > DBU AcO > TMG AcO > TBAF·xH2O. The efficiency of C4MeIm AcO relative to C3OMeIm AcO is due to higher solution basicity. Isothermal titration calorimetry was used to study cellobiose-solvent interactions. Except for TBAF·xH2O/DMSO, these interactions are exothermic; the relative solvent efficiency increases with increasing dissolution |enthalpy|. Using the mole fraction concentration scale to report cellulose dissolution avoids possible ambiguities. [ABSTRACT FROM AUTHOR]
Titel: |
Assessing cellulose dissolution efficiency in solvent systems based on a robust experimental quantification protocol and enthalpy data.
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Autor/in / Beteiligte Person: | Kostag, Marc ; Dignani, Marcella Teixeira ; Lourenço, Matheus Costa ; Bioni, Thaís de Almeida ; El Seoud, Omar A. |
Zeitschrift: | Holzforschung: International Journal of the Biology, Chemistry, Physics, & Technology of Wood, Jg. 73 (2019-12-01), Heft 12, S. 1103-1112 |
Veröffentlichung: | 2019 |
Medientyp: | academicJournal |
ISSN: | 0018-3830 (print) |
DOI: | 10.1515/hf-2019-0086 |
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