Standard enthalpy of transfer

We shall discuss now the variation of the three main thermodynamic functions with solvent composition for the case of n-Bu4NBr-water-acetone system and shall extend this discussion to the n-Bu4NBr-water-THF system. Figure 4 and Table IV present the results obtained. The figure was constructed as follows first the standard enthalpy of transfer AH°t, obtained by Ahluwalia and co-workers (12) from pure water to Z2 = 0.30, was used in order to get the standard entropy of transfer function from the relation ... 

As indicated by Eq. 6-9, the standard enthalpy of transfer of a compound i from water to air is given by ... 

Table 6.3 Experimental Standard Enthalpies of Vaporization (AvapH,) and Standard Enthalpies of Transfer from Water to Air (Aaw//,) of Selected Organic Compounds at 25 °C ... 

Extensive data also exist for the enthalpy of transfer of 1-1 electrolytes from water to non-aqueous solvents. These data are obtained in calorimetric experiments in which the enthalpy of solution is measured as a function of electrolyte concentration. The value of the enthalpy of solution per mole at infinite dilution is obtained by extrapolation. The enthalpy of transfer is defined in the same way as the Gibbs energy of transfer according to process (4.8.4). Thus, the standard enthalpy of transfer is given by... 

Methods for obtaining individual contributions to the enthalpy of solvation were discussed above. For the most part, identical procedures have been used to obtain the individual ionic contributions to the standard enthalpy of transfer. Appendix 2.11.15 lists these individual A/f°(ion) values. These data are based on the following methods ... 

Standard Enthalpies of Transfer of Ions, A/f(°(ion)/kcaI mol, from Water to Organic Solvents ... 

Equation (91) allows the evaluation of the molar standard enthalpy of transfer. For example (173), for CjqEg in water-hexane (Fig. 14), a linear relationship exists between... 

Figure 14 Logarithm of the partition coefficients of CjQEg in water/hexane vs. the inverse of temperature. The slope of the straight hne represents the standard enthalpy of transfer.

Yq surface tension of the pure solvent r = r F2 total adsorption 5 relative oscillation amplitude AHj molar standard enthalpy of transfer Anp density difference Sjj dilational elasticity dilational viscosity rig shear viscosity relative area change X=k/xn dimensionless rate constant interfacial chemical potential n = Yq-y surface tension co, co2 partial molar areas in - 27if circular frequency... 

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