Physico-chemical characterization of aqueous solutions of superbase ionic liquids with cellulose dissolution capability


Superbase-based ionic liquids 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-enium acetate, [mTBDH][OAc], and 5-methyl-1,5,7-triaza-bicyclo[4.3.0]non-6-enium acetate, [mTBNH][OAc], are good candidates to produce high performance cellulose fibres while presenting much easy spinnability and good recyclability, than the state-of-the-art ionic liquids. Nevertheless, the recovery of the IL from the aqueous spinning bath and its purification, which are both an economical and environmental necessity, are important aspects that are still not solved. Aiming to gather knowledge to recover and recycle superbase-ILs, the main goal of this work is the physicochemical characterization of the binary systems water + [mTBDH][OAc] or [mTBNH][OAc]. Measurements performed include solid-liquid equilibria, vapor-liquid equilibria, water activity, Kamlet -Taft solvatochromic parameters, densities, and viscosities. An experimental screening on possible hydrophobic extractants for the recuperation of the ionic liquids from aqueous solution was performed. Using butanol, an extraction efficiency of 37% for [mTBDH][OAc] was achieved. Better extraction efficiencies were achieved with chlorinated solvents, however, they seem to react with the ILs anion. (C) 2022 Elsevier B.V. All rights reserved.



subject category

Thermodynamics; Chemistry; Engineering


Martins, MAR; Sosa, FHB; Kilpelainen, I; Coutinho, JAP

our authors


This work was developed within the scope of the GRETE project funded from the Bio-Based Industries Joint Undertaking under the European Union's Horizon 2020 research and innovation program under grant agreement No 837527 -GRETE -H2020-BBI-JTI-2018. Additionally, this work was developed within the scope of the project CICECO Aveiro Institute of Materials, UIDB/50011/2020 &UIDP/50011/2020, financed by national funds through the Foundation for Science and Technology/MCTES, and National NMR Network, funded within the framework of the National Program for Scientific Re-equipment, contract REDE/1517/RMN/2005 with funds from POCI 2010 (FEDER) and FCT.

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