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Densities, Viscosities and Speeds of Sound of Binary Mixtures of Stereoisomeric Decalins

Siporska A., Szydłowski L.

Polish Journal of Chemistry

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2007

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Vol. 81, nr 4

599-605

EN

Densities, viscosities and speeds of sound for the binary mixture of cis- and transdecalins have been measured over the whole composition range at 293.15 K and 305.15 K. The limiting partial volumes, excess volumes, deviations in viscosity and isentropic compressibilitywere calculated. It appeared that the mixture of stereoisomeric decalins is characterized by a moderate excess volume and relatively small deviations in viscosity and isentropic compressibility. The results were fitted to the Redlich – Kister equation.

2

Influence of H/D Isotope Substitutio on Physicochemical Properties of Aqueous Solutions of Urea and Thiourea

Jelińska-Kazimierczuk M., Szydłowski J.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 1

115-125

EN

The influence of the H/D isotope substitution on excess volumes, partial molar volumes, viscosity and ultrasound speed in aqueous solutions of urea and thiourea are studied at 20 C. The excess volume of the solutions studied is relatively small - however, it is negative in urea and positive in thiourea solutions. On the other hand, the deuteration affects the excess volume in both solutions in the same way: deuterated systems show smaller deviation from additivity than regular ones. The speed of sound in the systems studied increases monotonously with concentration, but its isotope effect decreases as the concentration increases. The curves of viscosity are monotonous too, but isotope effect of kinematic viscosity is practically the same in the whole concentration range studied. The present results for urea and thiourea aqueous solutions are compared with those previously obtained for amide-water systems.

3

Effects of hydrophobic and hydrophilic hydration on the compressibility, volume and viscosity of mixtures of water with ß-picoline

Marczak W., Ernst S.

Bulletin of the Polish Academy of Sciences. Chemistry

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1998

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Vol. 46, No. 4

375-395

EN

The speed of ultrasound in and the density of mixtures of water with ,ß-picoline were measured in the whole concentration range and within the temperature limits 293 = 298 K. The viscosities of those mixtures were measured at 293 K. The molar compressibility, molar volume and the corresponding excess and partial functions as well as the coefficients of the adiabatic compressibility and the excess activation energy of viscous flow were calculated. The results were discussed in terms of hydrophobic and hydrophilic molecular interactions. The hydrophobic hydration becomes evident in the thermodynamic properties of dilute aqueous solutions in that most probably labile semiclathrate structures, resembling cubic II solid clathrates (symmetry group Fd3m) but with guest molecules hydrogenbonded to the water host lattice, arise. With increasing concentration of the organic component the shortage of water leads to a gradual decay of the water polyhedra around the picoline molecules and hydrophilic hydration becomes predominant.