Mariola Tkaczyk

Effect of non-electrolyte properties on the enthalpic interaction coefficients for NaCl/Nal–non-electrolyte pairs in water. Dissolution enthalpies of NaCl and Nal in aqueous solutions of butan-2-one and 1,2-dimethoxyethane at 25 °C

Dissolution enthalpies of NaCl and Nal in aqueous solutions of butan-2-one and 1,2-dimethoxyethane have been measured and appropriate enthalpic pair interaction coefficients, hxy(electrolyte–non-electrolyte) in water have been determined. These results along with the other data concerning the NaCl–non-electrolyte and Nal–non-electrolyte pairs taken from our earlier reports and from the literature, were analysed with respect to the effect of the non-electrolyte properties on variations of the hxy values in water. The hxy coefficients for both NaCl–nonelectrolyte and Nal–non-electrolyte systems are linearly correlated with the heat capacity of the non-electrolyte interaction with solvent water.The group contributions illustrating the interactions between the electrolyte (NaCl or Nal) and CH2, OH, O, CO, ‘Pep’ and ‘iPep’ groups in the non-electrolyte molecules were calculated and discussed from the viewpoint of a competition between the solute–solute and solute–solvent interactions.The analysed enthalpic pair interaction coefficients are well correlated through the multiparameter equation of the Abraham–Kamlet–Taft type.

Thermochemical properties of electrolyte solutions in 2-alkoxyethanol–water mixtures

Dissolution enthalpies for NaCl in mixtures of water with 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol at 298.15 K and for Nal in mixtures of water with 2-butoxyethanol at 298.15 K and 308.15 K have been measured. The standard solution enthalpies ΔsH° of the salts go through a maximum within the range of high water content. The position and the height of the maximum depend both on the nature of the salt and the size of the 2-alkoxyethanol molecule. It was conclued that 2-alkoxyethanols in water are hydrophobically hydrated and that their hydration shell is weaker than that of alkanols. The mixtures of water with 2-alkoxyethanols, when used as solvents for the electrolytes, exhibit some similarities in thermochemical properties both to water–alkanol mixtures and to mixtures of water with some aprotic solvents.

Thermochemical properties of NaI solutions in water―2-methoxyethanol and water―2-ethoxyethanol mixtures. The temperature dependence of enthalpic pair interaction coefficients in water solution

Abstract Enthalpies of solution of NaI in mixtures of water with 2-methoxyethanol and 2-ethoxyethanol (known as cellosolves) at 298.15, 308.15 and 318.15 K were measured. The enthalpies of solution in all investigated systems pass through a maximum in the water-rich region. This extremum is lower and flatter than that observed in water-unsubstituted alkanol mixtures. The enthalpic pair interaction coefficients h xy [(Na + +I − )-cellosolve] were calculated and compared with appropriate data for (Na + +I − )-alkanol pairs. The group additivity concept was used for the analysis of h xy coefficients calculated at 308.15 K, and the influence of the temperature change on the group contributions was discussed.

Conductivity study of NaCl and NaI solutions in water — 2-butoxyethanol mixtures at 298.15K. The effect of ion pairing on the standard dissolution enthalpies of NaCl and NaI

Abstract The electric conductivity of NaCl and NaI in water — 2-butoxyethanol mixtures was measured at 298.15K and analysed using Fuoss — Justice equation. For the both salts, the limiting molar conductance decreases and the equilibrium constant of ion-pair formation increases along with increase of 2-butoxyethanol content. The standard dissolution enthalpies of NaCl and NaI in water — 2-butoxyethanol mixtures were recalculated taking into account the ion — association process. The electric permittivity for mixtures of water with 2-butoxyethanol was measured over the whole composition range within 288.15 – 308.15K. The Kirkwood correlation factor for investigated mixtures was calculated.

Heat of solution of cholesterol and its interactions with different solvents: a calorimetric study

Abstract The values of the standard enthalpy of solution of cholesterol (Δ H s XXX ) in twelve solvents of various polarities and with different proton-acceptor and proton-donor properties were measured by calorimetry. The enthalpies of the cholesterol interaction and solvation in these media relative to cyclohexane were evaluated. Among the discussed factors affecting the solute-solvent interaction (dispersion, dipole and donor-acceptor interactions), the dispersion forces characterised by the Hildebrand solubility parameter was found to play a considerable role.

Enthalpies of dilution and solution of succinic, malonic, and glutaric acids in water at 298.15 K

Abstract Molar enthalpies of dilution of succinic acid in water at 298.15 K were measured by a “long-jump” method. Enthalpies of solution of three organic acids (malonic, succinic, and glutaric acid) in water at 298.15 K were measured. The molar enthalpies of solution extrapolated to infinite dilution are: malonic acid, Δ sol H m ∞ = 20.96 kJ · mol −1 ; succinic acid, Δ sol H m ∞ = 29.08 kJ · mol −1 ; glutaric acid, Δ sol H m ∞ = 24.98 kJ · mol −1 .

Enthalpies of solution of NaI and CsI in N,N-dimethylacetamide-water mixtures at 298.15 K

Abstract The enthalpies of solution Δ H s of NaI and CsI in N , N -dimethylacetamide-water mixtures at 298.15 K were measured. The standard enthalpies of solution of NaI determined in this study were compared with analogous functions for the systems containing formamide and N , N -dimethylformamide. The effect of cation size on the transfer enthalpy was analysed.

Calorimetric investigations of NaCl, NaI and urea solutions in water—1,2-dimethoxyethane mixtures

Abstract Enthalpies of solution Δ sol H ⊖ of NaI, NaCl and urea in water—1,2-dimethoxyethane (DME) mixtures at 25°C were measured. The enthalpies of solution for NaCl, NaI and urea exhibit a maximum within the water-rich region. NaI and urea show a minimum in the range of high DME content. The maxima are apparently due to the hydrophobic hydration of DME molecules. The minima can be explained as a result of competition between water and DME molecules in the solute solvation shell.

Phase Behavior and Heat Capacity of {DPnP + Water} Mixtures at the Temperature Range of 273.15–338.15 K

The differential scanning calorimetry method (DSC) was used to examine the miscibility in the dipropylene glycol propyl ether (DPnP)

The enthalpy of solution of sodium, potassium and caesium chlorides in propionic acid-water mixtures at 298.15 K

Abstract The enthalpies of solution of NaCl, KCl and CsCl in mixtures of water with propionic acid at 298.15 K were measured. The enthalpic pair interaction coefficients hxy (salt-propionic acid) and the group shares for the interactions of NaCl and KCl with carboxylic group were calculated.