Water−Ethanol Mixtures at Different Compositions and Temperatures. A Dieletric Relaxation Study
| Autor: | P. Petong, R. Pottel, Udo Kaatze |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Permittivity
Ethanol 010304 chemical physics Relaxation (NMR) Analytical chemistry 02 engineering and technology Dielectric Low frequency 021001 nanoscience & nanotechnology Mole fraction 01 natural sciences Spectral line chemistry.chemical_compound Dipole chemistry 0103 physical sciences Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | The Journal of Physical Chemistry A. 104:7420-7428 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/jp001393r |
| Popis: | At eight temperatures T between 0 and 60 °C and at five mole fractions xe of ethanol (0 < xe ≤ 1) the complex (electric) permittivity of ethanol/water mixtures has been measured as a function of frequency ν between 1 MHz and 24 GHz. At 25 °C the ethanol permittivities are completed by literature data for the frequency range 200 MHz to 90 GHz. The spectra for ethanol and for the ethanol/water mixtures are compared to permittivity spectra for water which, at some temperatures, are available up to 900 GHz. All spectra of the ethanol/water system can be well represented by the assumption of two relaxation regions. The relaxation time τ1 of the dominating relaxation process varies between 4 ps (xe = 0, 60 °C) and 310 ps (xe = 1, 0 °C). The relaxation time τ2 of the second relaxation process is smaller. Evaluation of the extrapolated low frequency (“static”) permittivity yields a minium in the effective dipole orientation correlation of the ethanol/water system at 0.2 ≤ xe ≤ 0.4. In this composition range, othe... |
| Databáze: | OpenAIRE |
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