Giuseppe Petrella

Solute-Solvent interactions in water-rich mixtures. II. Ionic conductances in water-dimethylsulfoxide mixtures at 25°C

Conductances of sodium bromide, iodide, and perchlorate, potassium chloride, and tetraphenylboride (BPh4−) as well as triisoamyl-n-butylammonium iodide (i-Am3BuNI) have been measured in aqueous mixtures containing up to 20 mole percent dimethylsulfoxide (DMSO) at 25°C. Experimental data were analyzed by the 1965 Fuoss-Onsager-Skinner (FOS) equation. Single-ion limiting equivalent conductances were calculated by assuming that λ0 (i−Am3BuN+=λ0 (BPh4−). The variations of the limiting ionic Walden products are discussed on the basis of acid-base type interactions for cations, and on the basis of structural effects for anions.

Excess volumes and viscosity of water—sulfolane mixtures at 30, 40 and 50°C

Abstract Densities and viscosities of water—sulfolane mixtures have been measured at 30, 40 and 50°C over the whole mole fraction range. From density data apparent molar volumes of both components and deviations from ideal volumes of mixing have been evaluated at the three temperatures. From viscosity data activation parameters of viscous flow have been computed. Data obtained seem to confirm that sulfolane acts as a structure-breaker to water even at low concentrations.

Volumes and heat capacities of binary liquid mixtures of water—sulfolane and water—hexamethylphosphotriamide

Abstract Density and heat capacity measurements of water—sulfolane mixtures at 303.15 K and water—hexamethylphosphotriamide mixtures at 298.15 K have been performed over the whole composition range. Molar, excess, apparent molar volumes and heat capacities were calculated for the two systems. The trends of these functions are discussed in terms of specific interactions between the components of the solvent mixtures and the changes caused by the organic solvents on the water structure.

Solute—Solvent interactions in water-rich mixtures. I. Ionic conductances in water—Acetonitrile mixtures at 25°C

Conductance measurements oni-Am3BuNI (TABI), NaBPh4, NaI, NaBr, NaCl, and KCl are reported for aqueous mixtures containing up to 20 mole% acetonitrile at 25°C. Experimental data were analyzed by the 1965 Fuoss-Onsager-Skinner equation. Limiting ionic equivalent conductances in water-acetonitrile mixtures were calculated assuming that the contribution to the limiting conductance foriAm3BuNBPh4 is the same for both ions involved. The trends observed for the limiting ionic conductance-viscosity products for several ions in these water-rich solvents are discussed in terms of structural effects and ion-solvent interaction.

Ionic conductances in water-sulfolane mixtures at 30°C

AbstractConductances of solutions of triisoamyl-n-butylammonium (iAm3BuN+) iodide and sodium tetraphenylboride, iodide, and bromide have been measured in water-sulfolane mixtures at 30°C. Experimental data were analyzed by the 1965 Fuoss-Onsager-Skinner equations. The limiting equivalent conductances of triisoamyl-n-butylammonium tetraphenylboride (iAm3BuNBPh4) in each solvent mixture were obtained by the equation

Ionic enthalpies of transfer from water to water-sulfolane mixtures

\Lambda _0 (iAm_3 BuNBPh_4 ) = \Lambda _0 ({\text{i}}Am_3 BuNI) + \Lambda _0 (NaBPh_4 ) - \Lambda _0 (NaI)

Walden product, ion-solvent interactions and solvent structure in water-rich mixtures ionic conductances in water-sulfolane, water-acetonitrile and water-dimethylsulfoxide

Limiting ionic equivalent conductances in water-sulfolane mixtures were calculated on the assumption thatι0(iAm3BuNBPh4)/2λ0(iAm3BuN+)=λ0(BPh-4). The variations of the limiting ionic Walden product with solvent composition are discussed with respect to current information concerning solvent structural effects and ion-solvent interaction.

Interaction potentials and collisional (V, T) transfer in HeN2 and ArN2 gaseous mixtures

Abstract The rotational-sudden approximation (IOSA) has been applied to He-HF scattering at intermediate energies by using an ab initio computed potential-energy surface which explicitly included the dependence on the internal molecular coordinate. The vibrational degree of freedom has therefore been treated exactly by solving the coupled radial equations that were obtained after expanding the target vibrations over a large number of HO wavefunctions. The radial behaviour of the computed coupling matrix elements between lower-lying target states is analyzed at various relative orientations of the atom-to-target vector with respect to the molecular bond. The present results clearly show that the coupling strength and range can be directly related to the specific anisotropic behaviour of the potential surface and to the varying efficiency of (V, T) coupling as the He atom probes different molecular regions. The computed relaxation times are compared with experiments at various temperatures and with previous calculations performed via different surfaces and dynamical models and show satisfactory agreement with observations, thus markedly improving the quality of earlier computed cross sections.