Mechanisms ruling the partition of solutes in ionic-liquid-based aqueous biphasic systems - the multiple effects of ionic liquids

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Passos, H (Author) Other; Dinis, TBV (Author) Other; Capela, EV (Author) Other; Quental, MV (Author) Other; Gomes, J (Author) Other; Resende, J (Author) Other; Madeira, PP (Author) Other; Freire, MG (Author) Other; Coutinho, JAP (Author) Other

Journal

Title: Physical Chemistry Chemical Physics

Vol. 20

Pages: 8411-8422

ISSN: 1463-9076

Publisher: Royal Society of Chemistry

Indexing

ISI Web of Knowledge - 3 Citations

Scopus - 8 Citations

Other information

Authenticus ID: P-00N-V0G

DOI: 10.1039/c8cp00383a

Abstract (EN): In the past decade, the remarkable potential of ionic-liquid-based aqueous biphasic systems (IL-based ABSs) to extract and purify a large range of valued-added biocompounds has been demonstrated. However, the translation of lab-scale experiments to an industrial scale has been precluded by a poor understanding of the molecular-level mechanisms ruling the separation or partition of target compounds between the coexisting phases. To overcome this limitation, we carried out a systematic evaluation of specific interactions, induced by ILs and several salts used as phase-forming components, and their impact on the partition of several solutes in IL-based ABSs. To this end, the physicochemical characterization of ABSs composed of imidazolium-based ILs, three salts (Na2SO4, K2CO3 and K3C6H5O7) and water was performed. The ability of the coexisting phases to participate in different solute-solvent interactions (where solvent corresponds to each ABS phase) was estimated based on the Gibbs free energy of transfer of a methylene group between the phases in equilibrium, G(CH2), and on the Kamlet-Taft parameters - dipolarity/polarizability (*), hydrogen-bonding donor acidity () and hydrogen-bonding acceptor basicity () - of the coexisting phases. Relationships between the partition coefficients, the phase properties expressed as Kamlet-Taft parameters and COSMO-RS descriptors were established, highlighting the ability of ILs to establish specific interactions with given solutes. The assembled results clearly support the idea that the partition of solutes in IL-based ABSs is due to multiple effects resulting from both global solute-solvent and specific solute-IL interactions. Solute-IL specific interactions are often dominant in IL-based ABSs, explaining the higher partition coefficients, extraction efficiencies and selectivities observed with these systems when compared to more traditional ones majorly composed of polymers.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12