Barthel, Josef and Buchner, Richard and Wurm, B. (2002) The dynamics of liquid formamide, N-methylformamide, N,N-dimethylformamide, and N,N-dimethylacetamide. A dielectric relaxation study. Journal of Molecular Liquids 98-99, pp. 51-69.
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Dielec. relaxation was measured in liq. formamide (FA), N-methylformamide (NMF), DMF, and N,N-dimethylacetamide (DMA) 238.15-338.15 K in the frequency range from 0.2 to 89 GHz. Whereas the FA spectra can be formally fitted with a Davidson-Cole relaxation-time distribution, two relaxation process can be resolved for the other liqs. For DMF and DMA, the long relaxation time, τ1(T), follows the Vogel-Flucher-Tammann equation. For these liqs., τ1(T) probes the essentially isotropic rotational diffusion of the mol. dipole vector. For the hydrogen-bonding liqs. FA and NMF, a modified Eyring equation is more appropriate to describe τ1(T). From the parameters the av. no. of monomers in the chains of H-bonded NMF mols. is deduced, as well as the no. of hydrogen bonds which must be broken before relaxation in FA can occur. The data suggest that the obsd. high-frequency contribution in the spectra mainly reflects the onset of internal contributions.
|Institutions:||Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > PD Dr. Richard Buchner|
|Keywords:||alkylamide selfassocn d dielec spectroscopy|
|Subjects:||500 Science > 540 Chemistry & allied sciences|
|Refereed:||Yes, this version has been refereed|
|Created at the University of Regensburg:||Yes|
|Deposited On:||14 Jun 2012 13:09|
|Last Modified:||03 Jul 2012 08:43|