Agieienko, Vira and Harifi-Mood, Ali Reza and Buchner, Richard (2021) Cooperative dynamics and speciation in deep eutectic solvent plus DMSO mixtures. JOURNAL OF MOLECULAR LIQUIDS, 331: 115790. ISSN 0167-7322, 1873-3166
Full text not available from this repository. (Request a copy)Abstract
Dielectric relaxation (DR) spectra within the frequency range of 0.05 <= nu/GHz <= 89 were measured at T = 308.15 K to reveal structure and dynamics of mixtures of deep eutectic solvents (DESs) with dimethylsulfoxide (DMSO). Studied DESs were reline, glyceline and ethaline, ie. 1:2 molar ratio mixtures of choline chloride (ChCl) and the hydrogen bond donors (HBDs) urea, glycerol and ethylene glycol. The obtained DR spectra were best fit by a superposition of relaxations associated with the reorientation of dipolar DES components and individual DMSO molecules. In contrast to previously studied mixtures of glyceline and reline with water, the analysis of the obtained relaxation amplitudes revealed that the present DES/DMSO systems cannot be simply regarded as mixtures of individual Ch(+), Cl-, HBD and DMSO units over the entire mixture range. Instead, a significant amount of ChCl contact ion pairs (CIPs) is formed at moderate DES concentrations. Due to their high dipole moment these CIPs cause pronounced maxima at ChCl:HBD:DMSO ratios of similar to 1 : 2 : 9 in the static permittivity of the mixtures. Pronounced solute-solvent interactions slow down the rotational motion of solvating DMSO molecules. At infinite dilution the derived total effective solvation numbers, Z(t), extrapolate to similar to 8 - 9 DMSO per ethaline, similar to 16 per glyceline and similar to 7 - 8 per reline unit but numbers decrease rapidly with rising DES mole fraction. For the latter two DESs Zt could be split into ChCl and HBD contributions. Finally, careful analysis of the relaxation times provided evidence for pronounced micro-heterogeneity of the studied mixtures. (C) 2021 Elsevier B.V. All rights reserved.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | CHOLINE CHLORIDE; DIELECTRIC-RELAXATION; ETHYLENE-GLYCOL; IONIC LIQUIDS; ELECTRICAL-CONDUCTIVITY; VIBRATIONAL ANALYSIS; DIMETHYL-SULFOXIDE; CARBOXYLIC-ACIDS; BINARY-MIXTURES; VISCOSITY; Dielectric relaxation spectroscopy; Deep eutectic solvents; Dimethylsulfoxide; Solvation; Ion association; Micro-heterogeneity |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > PD Dr. Richard Buchner |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 16 Sep 2022 06:20 |
| Last Modified: | 16 Sep 2022 06:20 |
| URI: | https://pred.uni-regensburg.de/id/eprint/47488 |
Actions (login required)
 |
View Item |
