Mutual diffusion in binary mixtures of ionic liquids and molecular liquids by dynamic light scattering (DLS)

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autor(en): Rausch MH, Lehmann J, Leipertz A, Fröba AP
Zeitschrift: Physical Chemistry Chemical Physics
Verlag: Royal Society of Chemistry
Jahr der Veröffentlichung: 2011
Band: 13
Seitenbereich: 9525-9533
ISSN: 1463-9076
eISSN: 1463-9084
Sprache: Englisch


Abstract


The present study shows that dynamic light scattering (DLS) is capable of measuring mutual diffusion coefficients for binary mixtures of ionic liquids (ILs) with different molecular liquids over the complete composition range. Evidence is given that the light scattering signals are related to true molecular binary diffusion. The method stands out due to its ability to work non-invasively in macroscopic thermodynamic equilibrium with reasonable accuracy and within convenient measurement periods. Compared with other techniques, mixtures with distinctly higher viscosities can be probed. For exemplary binary mixtures of 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO(4)]) with acetone, acetonitrile, dichloromethane, ethanol, or water as well as of 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO(3)]) with acetone, water, or methanol, mutual diffusivity data were measured over a wide range of composition at a temperature of 293.15 K. In general, the mutual diffusivity increases with increasing mole fraction of the molecular liquid and similarities to aqueous solutions of classical inorganic salts can be found. The characteristic behavior of the mutual diffusion coefficients is influenced by the nature of the chosen molecular liquid. For IL water mixtures, low light scattering intensities were observed despite the large refractive index difference of the pure components. The reason for this behavior may be the existence of water clusters in the mixtures. Additional measurements for IL acetone mixtures at temperatures ranging from 278.15 K to 323.15 K showed that the temperature dependence of the mutual diffusivity can be represented by Arrhenius functions and is increasing for decreasing mole fractions of acetone.



FAU-Autoren / FAU-Herausgeber

Fröba, Andreas Paul Prof. Dr.-Ing.
Professur für Advanced Optical Technologies - Thermophysical Properties
Leipertz, Alfred Prof. Dr.-Ing.
Lehrstuhl für Technische Thermodynamik
Rausch, Michael Heinrich Dr.-Ing.
Lehrstuhl für Technische Thermodynamik


Zitierweisen

APA:
Rausch, M.H., Lehmann, J., Leipertz, A., & Fröba, A.P. (2011). Mutual diffusion in binary mixtures of ionic liquids and molecular liquids by dynamic light scattering (DLS). Physical Chemistry Chemical Physics, 13, 9525-9533. https://dx.doi.org/10.1039/c1cp20208a

MLA:
Rausch, Michael Heinrich, et al. "Mutual diffusion in binary mixtures of ionic liquids and molecular liquids by dynamic light scattering (DLS)." Physical Chemistry Chemical Physics 13 (2011): 9525-9533.

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Zuletzt aktualisiert 2018-13-07 um 09:23