A new model is developed for determination of the Soret coefficient and the enthalpy of transport for weak (pK ∼ 4-5) 1:1 type electrolytes in aqueous solutions. In the model the effects of both the thermal diffusion and the shift of the dissociation equilibrium with temperature and concentration are taken into account. The Soret coefficients of normal carboxylic acids - and also those of the ionic and molecular species separately - were calculated from the single ionic enthalpy of transport of the acidic anion. The results of calculations show that the differences between the enthalpies of transport of the ionic and molecular species are nearly identical with the enthalpies of dissociation. Furthermore, the values of the Soret coefficients increase linearly with the logarithm of the carbon number of the acid.
|Number of pages||7|
|Journal||Magyar Kemiai Folyoirat, Kemiai Kozlemenyek|
|Publication status||Published - Aug 1 1998|
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