Synthesis and characterization of analogues of glycine-betaine ionic liquids and their use in the formation of aqueous biphasic systems
authors Pereira, MM; Pedro, SN; Gomes, J; Sintra, TE; Ventura, SPM; Coutinho, JAP; Freire, MG; Mohamadou, A
nationality International
journal FLUID PHASE EQUILIBRIA
author keywords Ionic liquids; Analogues of glycine-betaine; Thermal properties; Ecotoxicity; Allvibrio fischeri; Aqueous biphasic systems; Phase diagram
keywords ENHANCED EXTRACTION; CATION; PHOSPHONIUM; TOXICITY; PRETREATMENT; SOLVENTS; RECOVERY; REMOVAL; BIOMASS; STRESS
abstract A series of novel analogues of glycine-betaine ionic liquids (AGB-ILs), viz. 1-(4-ethoxy-4-oxobutyl)-1-methylpyrrolidin-1-ium, N,N,N-tri(n-butyl)(4-ethoxy-4-oxobutyl)-1-phosphonium and N,N,N-tri-alkyl(4-ethoxy-4-oxobutyl)-1-aminium cations with ethyl, n-propyl and n-butyl alkyl chains, combined with the bromide anion, have been synthesized and characterized. Their synthesis and characterization by spectroscopic methods and elemental analysis is here reported. These ILs were further characterized in what concerns their thermal properties and ecotoxicity against Allvibrio fischeri, and compared with degrees the commercial tetra(n-butyl)ammonium and tetra(n-butyl)phosphonium bromide. The novel AGB-ILs described in this work have low melting points, below 100 degrees C, display high degradation temperatures (180-310 degrees C), and low toxicity as shown by being harmless or practically harmless towards the marine bacteria Allvibrio fischeri. Finally, the ability of the synthesized AGB-ILs to form aqueous biphasic systems with potassium citrate/citric acid (at pH 7) was evaluated, and the respective ternary phase diagrams were determined. It is shown that the increase of the cation alkyl chain length facilitates the creation of ABS, and that phosphonium-based ILs present a slightly better separation performance in presence of aqueous solutions of the citrate-based salt. (C) 2019 Elsevier B.V. All rights reserved.
publisher ELSEVIER SCIENCE BV
issn 0378-3812
year published 2019
volume 494
beginning page 239
ending page 245
digital object identifier (doi) 10.1016/j.fluid.2019.05.001
web of science category Thermodynamics; Chemistry, Physical; Engineering, Chemical
subject category Thermodynamics; Chemistry; Engineering
unique article identifier WOS:000472690200021

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