Solution behavior of iron(III)-N,N'-ethylene-bis-(salicylideneiminato)-chloride in aqueous methanol at 298.15, 303.15 and 313.15K

In this study partial molar volumes (?V0) and viscosity B-coefficients of iron(III)-N, N'-ethylene-bis(salicylideneiminato)-chloride, abbreviated as FeIII(salen)Cl, in different aqueous methanol solutions were determined from solution density and viscosity measurements at temperatures 298.15, 303.15, and 313.15 K under ambient pressure. Apparent molar volumes (?V) and densities (?) were used to calculate the apparent molar expansibilities (?E), the partial molar expansibilities (?E0) and the temperature dependence of the partial molar expansibilities (?E0) at constant pressure, (??E0/?T)P of FeIII(salen)Cl solutions to reveal the nature of different interactions in the ternary solutions. The transition state theory was applied to analyze the viscosity B-coefficients on the basis of the activation parameters of viscous flow. The overall results indicated strong solute-solvent interactions between FeIII(salen)Cl and the solvent molecules, preferentially with water molecules and that FeIII(salen)Cl acts as a net structure promoter in the ternary solutions. UV-VIS absorption spectra of the ternary solutions also stand in support of the results obtained.

Partial molar volumes of some dipolar ions in water at 35 °C

This work reports partial molar volumes, V0, of eight peptides and three other dipolar ions (glycine, diglycine, triglycine, dl-alanyl-dl-valine, glycyl-dl-alanine, glycyl-dl-leucine, glycyl-tyrosine dihydrate, dl-alanyl-glycyl-glycine, l-valyl-glycyl-glycine, l-lysine-l-aspartate, l-lysine-l-glutamate) in water, calculated from density data obtained at 35 °C. V0 data are interpreted in terms of solute–solvent interactions. In some cases where V0 data at 25 °C were available from the literature, a comparison indicates that partial molar volumes of these solutes at 35 °C are higher than their respective volumes at 25 °C by about 2–3 cm3 mol−1. Partial molar expansibilities, E0, were also estimated in such cases. Expansibility data appear to show a trend indicating dependence of E0 values on the chain length of the solute molecules. Some plausible modes of solute–solute interactions are also discussed. Keywords: hydration of dipolar ions, partial molar volumes of peptides, solute–solvent interactions, electrostriction, solute–solute interactions.

Volumetric studies of alcohols in water and aqueous micelle solutions of cetyltrimethylammonium bromide

The volumetric properties of 1-propanol, cyclohexanol and butoxyethanol in water and CTAB water mixtures have been studied. The apparent molar volumes of 1-propanol, cyclohexanol and butoxyethanol in water and in aqueous solutions of CTAB were determined from density data. The partial molar volumes of the alcohols in water and aqueous micelle solutions at infinite dilution, V20(mic) were obtained from apparent molar volume data and compared with the corresponding values. The standard partial molar expansibilities, E20(mic) of the solubilizates were evaluated from V20(mic) data at various temperatures. The volumetric studies of alcohols in CTAB micelles indicate that alcohols on the average are preferentially solubilized in the palisade layer of the micelle and increasing amount of each is transferred more deep into the palisade layer of the micelle with increasing surfactant concentration and temperature. The results of standard partial molar volume, V20 and standard partial molar expansibilities, E20 are reported and discussed. DOI: http://dx.doi.org/10.3329/jbcs.v24i2.9703 Journal of Bangladesh Chemical Society, Vol. 24(2), 143-157, 2011