Lubomír Hnědkovský

Excess molar volumes of binary liquid mixtures of “an oxygenated compound, or cyclopentane, or pentane + 1-bromo-1-chloro-2,2,2-trifluoroethane (halothane)’ at 298.15 K

Excess molar volumes of methanol +, propanol-2-ol +, propan-2-one +, methyl acetate +, tetrahydrofuran +, diethyl ether +, cyclopentane +, and pentane + 1-bromo-1-chloro-2,2,2-trifluoroethane (halothane) at 298.15 K are reported. Tilting dilution dilatometers were used to measure the excess volumes. The results indicate, in view of the structure of halothane and some other results from the literature, hydrogen-bond-like interactions of halothane with oxygenated compounds.

Partial molar volumes of organic solutes in water. IX. m-Aminophenol and benzonitrile at temperatures from 298 K to 573 K and o-cyanophenol at temperatures from 298 K to 498 K and at pressures up to 30 MPa

Density data for dilute aqueous solutions of 3-amino-1-hydroxybenzene (m-aminophenol), cyanobenzene (benzonitrile), and 2-cyano-1-hydroxybenzene (o-cyanophenol, o-hydroxybenzonitrile) are presented together with partial molar volumes at infinite dilution calculated from the experimental data. The measurements were performed at temperatures from T=298.15 K up to either T=573.15 K (m-aminophenol, benzonitrile) or T=498.15 K (o-cyanophenol) and at either atmospheric pressure, or at pressures close to the saturated vapor pressure of water, and also at p=30 MPa. The data were obtained using a high-temperature high-pressure flow vibrating-tube densimeter for measurements at elevated pressures and a commercial vibrating-tube cell DMA 602HT for measurements at atmospheric pressure.

Group Contributions for an Estimation of Partial Molar Volumes at Infinite Dilution for Aqueous Organic Solutes at Extended Ranges of Temperature and Pressure

Experimental data on the partial molar volume at infinite dilution in water for two groups of organic solutes (derivatives of benzene and aliphatic hydroxyl derivatives) measured using a vibrating-tube densimeter in the temperature and pressure ranges 298 to 573 K and 0.1 to 30 MPa are summarized. Smoothed values of partial molar volume as a function of temperature and pressure are employed for the evaluation of group and structural contributions. The contributions are used to estimate the partial molar volumes at infinite dilution in water for various solutes. The average deviation between partial molar volumes calculated from the contributions and the experimental data employed for the evaluation of the contributions is less than 1 cm3ċmol−1 in most cases. Predictions of partial molar volumes of solutes not included in the evaluation of the contributions are performed and results are compared with experimental data.

Partial molar volumes of organic solutes in water. VIII. Nitrobenzene and nitrophenols at T=298 K to T=573 K and pressures up to 30 MPa

Density data for dilute aqueous solutions of nitrobenzene and three isomeric nitrophenols (2-, 3-, or 4-nitro-1-hydroxybenzene) are presented together with partial molar volumes at infinite dilution calculated from the experimental data. The measurements were performed at T=298.15 K up to either T=573.15 K (nitrobenzene, m-nitrophenol) or T=548.15 K (p-nitrophenol) or T=523.15 K (o-nitrophenol) and at either atmospheric pressure, or at pressures close to the saturated vapor pressure of water, and also at p=30 MPa. The data were obtained using a high-temperature high-pressure flow vibrating-tube densimeter for measurements at elevated pressures and a commercial vibrating-tube cell DMA 602HT for measurements at atmospheric pressure.

(Vapour + liquid) equilibria, limiting activity coefficients, and excess molar volumes of {1-bromo-1-chloro-2,2,2-trifluoroethane (halothane) + tetrachloromethane or trichloromethane or 1,1,1-trichloroethane}

The thermodynamic behaviour of {1-bromo-1-chloro-2,2,2-trifluoroethane (halothane) + tetrachloromethane or trichloromethane or 1,1,1-trichloroethane} has been investigated. Excess molar volumes were determined at 298.15 K with a tilting dilution dilatometer, vapour-liquid equilibria were measured at 318.15 K by a dynamic method, and limiting activity coefficients were determined by comparative ebulliometry. The results obtained for the (vapour + liquid) equilibria were verified by effective statistical procedures and used to calculate excess Gibbs molar energies. The unknown second cross virial coefficients were calculated on the basis of redundant information provided by complete results for the (vapour + liquid) equilibria. The results support the hypothesis of weak solvation effects in (halothane + trichloromethane or 1,1,1-trichloroethane).

Excess molar volumes of (trifluoroethanoic acid+propanoic acid) at 298.15 and 318.15 K; an unusual composition dependence

Excess molar volumes VmE(T = 298.15 and 318.15 K, x), measured with a tilting dilution dilatometer, are reported for {(1−x)CH3CH2CO2H+xCF3CO2H}(l). The excess volumes are negative over the entire composition range with negative derivatives with respect to temperature. An outstanding feature of the results is the fact that the curve of excess volume against mole fraction exhibits one maximum and two minima at each temperature. Partial molar volumes, evaluated from a polynomial fitted to the results, are graphically presented as well.

On a temperature dependence of the van der Waals volume parameter in cubic equations of state

A dependence of the van der Waals volume parameter on temperature in cubic equations of state is analysed from the point of view of a consistency in the description of the compressed liquid region. The analysis shows that there may be a region in a PϱT space where the thermal pressure coefficient and the isobaric thermal expansion coefficient are negative if the van der Waals volume parameter decreases with increasing temperature. The results of the analysis are illustrated with a volume-translation method, which is the special case of the temperature dependence of the van der Waals volume parameter.

A simple method for evaluation of parameters of the Bender equation of state from experimental data

A simple numerical method for evaluation of parameters (constants) of Bender equation of state for pure fluids is proposed. The minimisation of the objective function leads to a set of linear equations. The method employs experimental data on state behaviour (p–ρ–T) of fluid phases, vapour–liquid equilibrium data (saturated vapour pressures and orthobaric densities), second virial coefficients, and the coordinates of the gas–liquid critical point. Results of the tests using data for two fluids (methane and n-pentane) are presented.