abstract
Although highly relevant to a priori select adequate solvents for a given application, the determination of the hydrogen-bond acidity or proton donor ability of aqueous solutions of ionic liquids is a difficult task due to the poor solubility of the commonly used probes in aqueous media. In this work, we demonstrate the applicability of the pyridine-N-oxide probe to determine the hydrogen-bond acidity of both neat ionic liquids and their aqueous solutions, based on C-13 NMR chemical shifts, and the suitability of these values to appraise the ability of ionic liquids to form aqueous two-phase systems.
keywords
SOLVATOCHROMIC COMPARISON METHOD; PYRIDINE-N-OXIDE; BIPHASIC SYSTEMS; EXTENDED SCALE; PI-STAR; SOLVENTS; EXTRACTION; PARAMETERS; BEHAVIOR; POLARITY
subject category
Chemistry; Physics
authors
Madeira, PP; Passos, H; Gomes, J; Coutinho, JAP; Freire, MG
our authors
Helena Passos
Researcher
João Manuel Costa Araújo Pereira Coutinho
Vice-Director
Mara Guadalupe Freire Martins
Research Coordinator
Pedro António Palma Madeira
ResearcherProjects
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Igy Technology: A Purication Platform using Ionic-Liquid-Based Aqueous Biphasic Systems (IGYPURTECH)
acknowledgements
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. The authors also acknowledge FCT for the doctoral grant SFRH/BD/85248/2012 of H. Passos, and post-doctoral fellowship SFRH/BPD/111113/2015 of P. P. Madeira. M. G. Freire acknowledges the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 337753.