The liquid structure of a representative of the first water-in-salt (WiS) Natural Deep Eutectic Solvents (NADES), hereinafter indicated as aquoline, a mixture of choline chloride (ChCl) and water with molar ratio 1:3.33, is ex- plored at ambient conditions. Using Molecular Dynamics (MD) simulation tools, we extract structural informa- tion at atomistic level on the nature of inter-correlations between the different moieties. Despite being a very fluid liquid, with much lower viscosity than other common ChCl-based DES, aquoline turns out to be very struc- tured. Computed X-ray and neutron weighted scattering patterns (the latter also on selectively deuterated mix- tures) highlight the existence of mesoscopic organization that is rationalised in terms of choline vs. water/ chloride structural alternation. The study shows that choline cations are highly coordinating the surrounding en- vironment: strong hydrogen bonding mediated correlations between the hydroxyl group and water or chloride are detected. In addition, the ammonium group drives the formation of a complex solvating environment, with water, chloride and hydroxyl moieties approaching it, between the hindering methyl groups. Strong hydrogen- bonding interactions between water molecules and between water and anions are detected and, while water cannot create a bulk water-like environment around itself, its network with neighbour water or anions develops long chains across the bulk phase. This is a first study that will be extended based on complementary experimen- tal work as a function of water content and temperature/pressure, to explore structural and dynamic properties of this class of materials.

Triolo, A., Lo Celso, F., Brehm, M., Di Lisio, V., Russina, O. (2021). Liquid structure of a choline chloride-water natural deep eutectic solvent: A molecular dynamics characterization. JOURNAL OF MOLECULAR LIQUIDS, 331 [10.1016/j.molliq.2021.115750].

Liquid structure of a choline chloride-water natural deep eutectic solvent: A molecular dynamics characterization

Lo Celso, Fabrizio
Membro del Collaboration Group
;
2021-03-30

Abstract

The liquid structure of a representative of the first water-in-salt (WiS) Natural Deep Eutectic Solvents (NADES), hereinafter indicated as aquoline, a mixture of choline chloride (ChCl) and water with molar ratio 1:3.33, is ex- plored at ambient conditions. Using Molecular Dynamics (MD) simulation tools, we extract structural informa- tion at atomistic level on the nature of inter-correlations between the different moieties. Despite being a very fluid liquid, with much lower viscosity than other common ChCl-based DES, aquoline turns out to be very struc- tured. Computed X-ray and neutron weighted scattering patterns (the latter also on selectively deuterated mix- tures) highlight the existence of mesoscopic organization that is rationalised in terms of choline vs. water/ chloride structural alternation. The study shows that choline cations are highly coordinating the surrounding en- vironment: strong hydrogen bonding mediated correlations between the hydroxyl group and water or chloride are detected. In addition, the ammonium group drives the formation of a complex solvating environment, with water, chloride and hydroxyl moieties approaching it, between the hindering methyl groups. Strong hydrogen- bonding interactions between water molecules and between water and anions are detected and, while water cannot create a bulk water-like environment around itself, its network with neighbour water or anions develops long chains across the bulk phase. This is a first study that will be extended based on complementary experimen- tal work as a function of water content and temperature/pressure, to explore structural and dynamic properties of this class of materials.
30-mar-2021
Settore CHIM/02 - Chimica Fisica
Triolo, A., Lo Celso, F., Brehm, M., Di Lisio, V., Russina, O. (2021). Liquid structure of a choline chloride-water natural deep eutectic solvent: A molecular dynamics characterization. JOURNAL OF MOLECULAR LIQUIDS, 331 [10.1016/j.molliq.2021.115750].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10447/511347
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