abstract
Deep eutectic solvents (DES) have been proposed as phase-forming compounds of aqueous biphasic systems (ABS). However, due to DES nature and the high water content of the ABS, their nature and behavior remains controversial. To foster the understanding of DES-based ABS, the present work uses the relative hydrophilicity of the hydrogen bond donor (HBD) as a descriptor to clarify its role on ABS formation and phase properties. Dipotassium phosphate (K2HPO4)-based ABS phase diagrams composed of cholinium chloride (N111(2OH)Cl), as hydrogen bond acceptor (HBA), and several HBD (alcohols and sugars) were compared in molality units and the saturation solubility point for each binodal curve determined. The results here reported establish the HBD role as function of its relative hydrophilicity: very hydrophilic HBD act only as an adjuvant in the formation of ABS; HBD of intermediate hydrophilicity influence the ABS formation; while the most hydrophobic HBD tend to form organic-aqueous two-phase systems, where the HBA acts as an adjuvant to the system. (C) 2019 Elsevier B.V. All rights reserved.
keywords
2-PHASE SYSTEMS; IONIC-LIQUID; EXTRACTION; TERNARY; SALTS
subject category
Thermodynamics; Chemistry; Engineering
authors
Farias, FO; Pereira, JFB; Coutinho, JAP; Igarashi-Mafra, L; Mafra, MR
our authors
Jorge Fernando Brandão Pereira
PhD Studentacknowledgements
F. O. Farias acknowledges CAPES and Fundacao Araucaria for the post-doctoral fellowship (88887.354435/2019-00). M. R. Mafra, and L. Igarashi-Mafra is grateful to the Brazilian National Council for Scientific and Technological Development (CNPq -Grant 310182/2018-2 and 308517/2018-0, respectively). J. F. B. Pereira acknowledges the support of FAPESP through the projects 2014/16424-7 and 2018/50009-8. This work was partly developed in the scope of the project CICECO Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2019) financed by national funds through the FCT/MCTES (PIDDAC) and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement.