1. Volumetric properties of ethanol-water mixtures under high pressureAljana Petek, Darja Pečar, Valter Doleček, 2001, izvirni znanstveni članek Opis: Densities of ethanol-water mixtures have been measured using a vibrating tube densimeter and a different arrangement high-pressure experimental set-up. Measurements were carried out at 298,15 K in a pressure range from 0.1 MPa to 5MPa. Partial molar volumes, excess molar volumes and coefficients of isothermal compressibility were calculated. The molar volumes of alcohol and its partial molar volumes in mixtures with water are found to decrease monotonously with increasing pressure. Excess molar volumes are negative at all pressures. The numerical P-V relations at each composition are correlated satisfactorily as a function of pressure by the Hayward equation.
Ključne besede: chemistry, high-pressure vibrating tube densimeter, excess molar values, isothermal compressibility
Objavljeno v DKUM: 10.07.2015; Ogledov: 1507; Prenosov: 112
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2. Temperature and pressure dependence of volumetric properties for binary mixtures of n-heptane and n-octaneDarja Pečar, Valter Doleček, 2007, izvirni znanstveni članek Opis: The densities of n-heptane, n-octane and their binary mixtures were measured at 298.15, 323.15 and 348.15 K and within the pressure range 0.1 to 40 MPa using a vibrating tube densimeter. The reliability of this technique has been verified in our previous works. The partial molar volumes, excess molar volumes, isothermal compressibilities, isobaric thermal expansivities and internal pressures were calculated from the obtained densities. This study presents the dependence of densities, partial molar volumes, excess molar volumes, isothermal compressibilities, isobaric thermal expansivities and internal pressures on composition, temperature and pressure.
Ključne besede: density measurements, partial molar volume, excess molar volume, isothermal compressibility, isobaric thermal expansivity, internal pressure, n-heptane, n-octane
Objavljeno v DKUM: 10.07.2015; Ogledov: 1689; Prenosov: 128
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3. Thermodynamic properties of coenzyme Q10 in supercritical carbon dioxideDarja Pečar, Valter Doleček, 2007, izvirni znanstveni članek Opis: The densities of coenzyme Q10 in supercritical carbon dioxide were measured at 308.15, 313.15, 323.15 and 333.15 K and in the pressure range from 10 to 40 MPa with the vibrating tube densimeter. The reliability of the technique has been verified in our previous works and in the present work it was checked comparing our experimental densities of pure carbon dioxide with literature data. The partial molar volumes, isothermal compressibilities, isobaric thermal expansivities, internal pressures and cluster sizes were calculated from obtained densities.
Ključne besede: koenzim Q10, density measurements, partial molar volume, isothermal compressibility, isobaric thermal expansivity, internal pressure, supercritical carbon dioxide
Objavljeno v DKUM: 01.06.2012; Ogledov: 1927; Prenosov: 147
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4. Volumetric properties of ethanol-water mixtures under high temperatures and pressuresDarja Pečar, Valter Doleček, 2005, izvirni znanstveni članek Opis: The densities of ethanol and ethanol-water mixtures were measured with a vibrating tube densimeter at 25.0, 50.0 and 75.0°C in the pressure range from 0.10 to 40.00 MPa. Densities were correlated using an empirical model. Partial molar volumes, excess molar volumes, isothermal compressibilities, cubic expansion coefficients and internal pressures were calculated from obtained densities. This study reports the dependence of densities, partial molar volumes, excess molar volumes, isothermal compressibilities, cubic expansion coefficients and internal pressures on composition, temperature and pressure.
Ključne besede: ethanol, ethanol-water mixtures, density measurements, vibrating U tube densimeter, partial molar volumes, isothermal compressibility, isobaric expansibility, cubic expansion coefficient, internal pressure
Objavljeno v DKUM: 01.06.2012; Ogledov: 2656; Prenosov: 146
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