Małgorzata Jóźwiak

Heat of solution of 15-crown-5 ether in the mixtures of water with DMSO, DMF, DMA and HMPA at 298.15K

Abstract Enthalpies of solution of 15-crown-5 ether in dimethylsulfoxide-water, N,N-dimethylformamide-water, N,N-dimethylacetamide-water, and hexamethylphosphoramide-water systems have been measured at 298.15K. The plot of enthalpy of solution of 15C5 in these mixtures exhibits maximum at xw ≈ 0.5 for DMSO and DMA, xw ≈ 0.4 for DMF, xw ≈ 0.7 for HMPA, respectively. The results were discussed on the basis of the “cage model” of hydrophobic hydration.

Thermochemical behaviour of crown ethers in the mixtures of water with organic solvents. Part III. Hydrophobic hydration and preferential solvation of crown ethers in water-amide mixtures at 298.15 K

Enthalpies of solution of 15-crown-5 (15C5) and benzo-15-crown-5 ether (B15C5) in the mixture of water with formamide (F) and N-methylformamide (NMF) have been measured at 298.15 K. The values of standard enthalpies of solution of 15C5 are negative and those of B15C5 are positive in the mixtures. The results of calorimetric measurements of dissolution enthalpies of 15C5 and B15C5 in the mixture of water and organic solvents at 298.15 K are discussed with regard to the intermolecular interactions that occur in the solution. Considering the properties and molecular structure of the examined crown ethers, particular attention is given to the hydrophobic hydration and preferential solvation of solute in the mixed solvents. The preferential solvation in the examined systems was analysed using the Covington model developed by Balk and Somsen. The relative importance of the solvation mechanism appeared to depend on co-solvent properties.

Thermochemical behaviour of crown ethers in the mixtures of water with organic solvents.: Part V. Enthalpy of solution of 12-crown-4 and 18-crown-6 ethers in the mixtures of water with dimethylsulfoxide or N,N-dimethylformamide at 298.15 K

Abstract The enthalpy of solution of crown ethers (12-crown-4 and 18-crown-6 ethers) in the mixtures of water with dimethylsulfoxide or N,N -dimethylformamide has been measured within the whole mole fraction range at 298.15 K. The plots of enthalpy of solution of 12-crown-4 ether in these mixtures exhibit a maximum at x w ≈0.5 for 12C4 and that for 18C6 at x w ≈0.4. The results were compared with the standard enthalpies of solution of 15-crown-5 and benzo-15-crown-5 ethers in the same mixtures at 298.15 K. The molar enthalpy of hydrophobic hydration, Hb(W), per one -CH 2 CH 2 O-group in 12-crown-4, 15-crown-5 and 18-crown-6 ethers in water was calculated and it is equal to (−12 ± 2) kJ mol −1 .

Calorimetric investigations of solutions of CsI, NaBPh4 and Ph4PCl in the HMPT–water system at 298.15 K

The enthalpies of solution of CsI, NaBPh4 and Ph4PCl in hexamethyl-phosphoramide (HMPT)–water mixtures have been measured at 298.15 K. Standard enthalpies of solution were calculated. Enthalpies of transfer from water to the mixed solvent were divided into ionic contributions for BPh–4, Ph4P+, Cs+, K+, Na+, I– and Cl– employing the assumption: ΔH°tr(Ph4P+)=ΔH°tr(BPh–4).

Thermodynamics of interactions of Na+ ion with 15-crown-5 ether in the mixtures of water with dimethylsulfoxide at 298.15 K

Standard enthalpies of solution of crown ether (15-crown-5 ether) in the dimethylsulfoxide-water-sodium iodide system have been measured at 298.15 K. The equilibrium constants of complex formation of 15-crown-5 with sodium iodide have been determined by the 13C NMR chemical shift of 15-crown-5 ether and by conductivity measurements at various molar ratios of 15-crown-5 ether and sodium iodide in the mixtures of water with dimethylsulfoxide at 298.15 K. The thermodynamic functions of 15-crown-5 ether complex formation with sodium iodide were calculated. The linear enthalpy-entropy relationship for complex formation was discussed. The enthalpies of transfer of the complex from pure dimethylsulfoxide to the examined mixtures were calculated and discussed.

Complex Formation of Crown Ethers with Cations in Water–Organic Solvent Mixtures. III. Thermodynamics of Interaction Between Na+ Ion with 15-Crown-5 Ether in Water–Acetonitrile Mixtures at 25°C

Enthalpies of solution of 15-crown-5 ether in the acetonitrile–water–sodium iodide system have been measured at 25°C. The equilibrium constants of complex formation of 15C5 with sodium iodide have been determined by molar conductance at various mole ratios 15C5 to sodium iodide in mixtures of water with acetonitrile at 25°C. The thermodynamic functions for complexation of the crown ether with Na+ were calculated. From the result, the standard Gibbs energies of complex formation as a function of the normalized Lewis acidity parameters ENT and enthalpy of solvation of 15C5 in the mixtures of water with acetonitrile have been analyzed. The enthalpies of transfer of the 15C5 complex with sodium iodide from pure acetonitrile to the mixtures studied were calculated and discussed.

Calorimetric investigations of solutions of NaI, KI, NaCl, KCl, and C6H5NH2 in [xPO“N(CH3)2’3 + (1 − x)H2O] at 298.15 K

Abstract Enthalpies of solution of NaI, KI, NaCl, KCl, and C6H5NH2 in [x PO“N(CH 3 ) 2 ’ 3 + (1 − x) H 2 O ] were measured at 298.15 K. Standard enthalpies of solution were calculated. They have maxima at x = 0.015 for NaI and KI, at x = 0.100 for NaCl and KCl, and at x = 0.045 for C6H5NH2. The results obtained experimentally are discussed against the background of the relevant literature.

Some remarks concerning hydrophobic effects parameters

Abstract The enthalpies of NaBPh 4 solution in binary mixtures of water with glycerol and acetonitrile were measured at 25°C. Some functions and parameters which can serve as measures of the hydrophobic effects were compared quantitatively with the semi-theoretical Kessler criterion (∂ B 22 /∂ P ) T .

Enthalpies of transfer of several ions from water to water-n-propanol mixtures at 298.15 K

Abstract Measurements were made of the dissolution heats of NaBPh 4 and Ph 4 PCl in water- n -propanol mixtures over the whole range of compositions. Assuming the equality of Δ H tr + ⊖ (Ph 4 P + ) and Δ H tr + ⊖ (BPh − 4 ), the transfer enthalpies of several ions from water to water- n -propanol mixtures at 298.15 K were calculated.

Complex Formation of Crown Ethers with Cations in Water–Organic Solvent Mixtures. Part IV. Thermodynamics of Interaction of Na+ Ion with Benzo-15-crown-5 Ether in the Mixtures of Water with Acetonitrile at 298.15 K

The equilibrium constants of complex formation of benzo-15-crown-5 ether with sodium ion have been determined by molar conductance at various molar ratios of benzo- 15-crown-5 ether and sodium iodide in mixtures of water with acetonitrile at 298.15 K. The thermodynamic quantities of complex formation of benzo-15-crown-5 ether with sodium cation are calculated. The enthalpy of solvation of benzo-15-crown-5 ether and sodium ion complex is discussed together with solvation enthalpies of the cation and ligand. The contribution of the benzene ring to the thermodynamic properties of complex formation and to the enthalpy of solvation of the crown ether/ Na+ complex in the mixtures of water with acetonitrile are analyzed and discussed.