Thermally Triggered Phase Separation of Organic Electrolyte-Cellulose Solutions

Organic electrolyte solutions (OES)—binary mixtures of an ionic liquid (IL) with a neutral polar aprotic co‐solvent—are being recognized as excellent candidate solvents for the dissolution, derivatization, and sustainable processing of cellulose. These solutions exhibit the beneficially combined pro...

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Bibliographic Details
Published in:ChemSusChem 2016-12, Vol.9 (23), p.3324-3329
Main Authors: de Oliveira, Heitor F. N., Clough, Matthew T., Rinaldi, Roberto
Format: Article
Language:English
Subjects:
Acetates
Cellulose
Cellulose - chemistry
Cellulose - isolation & purification
Design for recycling
Dissolution
Electrolytes
Enrichment
Imidazoles
ionic liquids
Ionic Liquids - chemistry
organic electrolytes
Phase separation
Recycling
Solubility
Solutions - chemistry
Solvents
Solvents - chemistry
Sustainability
Temperature
thermodynamics
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Summary:Organic electrolyte solutions (OES)—binary mixtures of an ionic liquid (IL) with a neutral polar aprotic co‐solvent—are being recognized as excellent candidate solvents for the dissolution, derivatization, and sustainable processing of cellulose. These solutions exhibit the beneficially combined properties of rapid‐to‐instantaneous cellulose dissolution, raised thermal stability, and reduced viscosity, compared to cellulose solutions in the parent ILs. Herein, we report the reversible, thermally triggered phase separation of cellulose solutions in 1‐ethyl‐3‐methylimidazolium acetate with 1,3‐dimethyl‐2‐imidazolidinone. In these solutions, cellulose drives the process of phase separation, resulting in a lower, IL‐rich layer in which the biopolymer is segregated. In turn, the upper phase is enriched in the neutral co‐solvent. We show that the temperature of phase separation can be fine‐tuned by modification of mole fractions of IL, co‐solvent, and cellulose. This finding holds promise for the design of strategies for separation and solvent recycling in cellulose chemistry. Some like it cold: Ternary mixtures of 1‐ethyl‐3‐methylimidazolium acetate, 1,3‐dimethyl‐2‐imidazolidinone, and cellulose exhibit unexpected reversible, tunable, and thermally triggered liquid–liquid phase‐separation behavior. This could open up new horizons for applications in cellulose derivatization to high‐value‐added products that currently are performed in environmentally unfriendly solvents.
ISSN:1864-5631
1864-564X
DOI:10.1002/cssc.201601108