Thermal expansivity,volume and the effect of pressure on the isobaric heat capacity of 1-hexanamine from 0.1 to 400 MPa at 303, 353, 403 and 453 K

The thermal expansivity of 1-hexanamine has been determined as a function of pressure up to 400 MPa over the temperature range from 303 to 453 K. Measurements were performed in a pressure-scanning calorimeter by the stepwise technique. The compressibility as a function of pressure at 303 K was determined using the technique described before. The molar volume under atmospheric pressure was determined from the density measurements with a Paar instrument. From both the molar volume as a function of pressure at 303 K and the thermal expansivities the effects of pressure on the isobaric heat capacity were determined over the whole pressure and temperature range under study.

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Zusammenfassung Im Temperaturbereich 303–453 K wurde bis zu einem Druck von 400 MPa die Wärmeausdehnung von 1-Hexanamin als eine Funktion des Druckes ermittelt. Die Messungen wurden in einem Druck-Scanning Kalorimeter durch schrittweises Vorgehen ausgeführt. Unter Anwendung derselben Technik wurde bei 303 K die Kompressibilität als eine Funktion des Druckes ermittelt. Das molare Volumen bei atmosphärischem Druck wurde aus Dichtemessungen mit einem Paar-Instrument bestimmt. Aus dem molaren Volumen als eine Funktion des Druckes bei 303 K und den Wärmeausdehnungen wurde der Einfluß des Druckes auf die isobare Wärmekapazität über den gesamten untersuchten Druck- und Temperaturbereich bestimmt.

     

Thermophysical properties of 1-hexanol over the temperature range from 303 K to 503 K and at pressures from the saturation line to 400 MPa

Isobaric thermal expansivities, _P(T,p), of 1-hexanol have been measured in a pressure-controlled scanning calorimeter from just above the saturation vapour pressure to 400 Mpa at temperatures from 302.6 K to 503.15 K. The specific volume isotherm, v(T_R,p), at T_R=302.6 K has been derived from measurements of isothermal compressibilities up to 400 MPa and from the specific density at atmospheric pressure. Specific volumes, isothermal compressibilities, thermal pressure coefficients, and isobaric and isochoric heat capacities for the whole pressure and temperature range are derived from these data and from literature data on the saturation vapour pressures and on the isobaric heat capacities at atmospheric or saturation vapour pressure.     

Isobaric thermal expansivities of polyethylenes with various crystallinities over the pressure range from 0.1 to 300 MPa and over the temperature range from 303 to 393 K

A pressure-controlled scanning calorimeter (PCSC) has been applied for measuring the isobaric volume thermal expansivities (α_p) of crystalline polymers as a function of pressure up to 300 MPa at various temperatures. The measurements have been performed for several well-defined polyethylenes with various degrees of crystallinity at 302.6, 333.0, 362.6, and 393.0 K. The results are reported as values of coefficients in a correlation equation, which facilitates the use of reported data over large ranges of temperature and pressure. The general pressure-temperature behavior of α_p for all polyethylenes under study is such that α_p increases with temperature and decreases with pressure. The increase with temperature is smaller at high pressures and the isotherms of α_p have a tendency to converge at high pressures; α_p decreases linearly with the crystallinity of the polyethylene over the whole range of pressure and temperature under investigation. From the linear approximation of experimental data for polyethylenes with various crystallinities the estimated α_p for both crystal and amorphous phases of polyethylenes have been determined as a function of pressure up to 300 MPa at 302.6, 333.0, and 362.5 K. The obtained results have been compared with available literature crystallographic data and with the values derived from the Pastine theoretical equation of state for both crystalline and amorphous phases. © 1996 John Wiley & Sons, Inc.     

Thermal expansivity,volume and the effect of pressure on the isobaric heat capacity of 1-hexanamine-1 hexanol mixtures from 0.1 to 400 MPa at 303 K up to 453 K

Thermal expansivities of liquid mixtures of 1-hexanol and 1-hexanamine have been determined as a function of pressure up to 400 MPa over the temperature range from 303 to 453 K. Measurements were performed in a pressure-scanning calorimeter by the stepwise technique. Compressibilities of the mixtures under study were determined at 303 K using the technique described before. Molar volumes under atmospheric pressure were determined for each mixture from the density measurements with a Paar instrument. From both the molar volume as a function of pressure at 303 K and the thermal expansivities the effects of pressure on the isobaric heat capacity were determined over the whole pressure and temperature range under study.

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Zusammenfassung Im Temperaturbereich 303–453 K wurde der thermische Ausdehungskoeffizient flüssiger Gemische aus 1-Hexanol und 1-Aminohexan als Funktion des Druckes bis 400 MPa bestimmt. Die Messungen wurden in einem Druck-Scanningkalorimeter nach der Schritt-für-Schritt-Methode ausgeführt. Die Kompressibilität der untersuchten Gemische wurde bei 303 K mittels der bereits beschriebenen Methode bestimmt. Mittels Dichtemessungen in einem Paar-Gerät wurde für jedes Gemisch das molare Volumen bei Atmosphärendruck ermittelt. Anhand der Druckabhängigkeit des molaren Volumens bei 303 K sowie der thermischen Ausdehnungskoeffizienten wurde der Einflu\ des Druckes auf die isobare Wärmekapazität im gesamten untersuchten Druck- und Temperaturintervall bestimmt.

     

Liquid density of 1-pentanol at pressures up to 140 MPa and from 293.15 to 403.15 K

This work reports new density data (180 points) of 1-pentanol at twelve temperatures between 293.15 and 403.15 K, and pressures up to 140 MPa (every 10 MPa). A new Anton Paar vibrating-tube densimeter, calibrated with an uncertainty of ±0.5 kg m⁻³ was used to perform these measurements. The experimental density data were fitted with the Tait-like equation with low standard deviations. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.     

Liquid density of 1-butanol at pressures up to 140 MPa and from 293.15 K to 403.15 K

This work reports new density data (178 points) of 1-butanol at twelve temperatures between 293.15 and 403.15 K (every 10 K), and fifteen pressures from 0.1 up to 140 MPa (every 10 MPa). An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.5 kg m⁻³ was used to perform these measurements. The experimental density data were fitted with the Tait-like equation with low standard deviations. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.     

Liquid density of biofuel mixtures: 1-Heptanol + heptane system at pressures up to 140 MPa and temperatures from 298.15 K to 393.15 K

This work reports new experimental density data (954 points) for binary mixtures of 1-heptanol + heptane over the composition range (seven compositions; 0 ⩽ 1-heptanol mole fraction x ⩽ 1), between 298.15 and 393.15 K, and for 23 pressures from 0.1 MPa up to 140 MPa. An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.7 kg · m⁻³ was used to perform these measurements. The experimental density data were fitted with a Tait-like equation with low standard deviations. Excess volumes have been calculated from the experimental data. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation, provided as supplementary material.     

Liquid density of oxygenated additives to biofuels: 2-Butanol at pressures up to 140 MPa and temperatures from (293.15 to 393.27) K

This work reports new density data (159 points) of 2-butanol at seven temperatures between (293.15 and 393.27) K and 23 pressures from (0.1 to 140) MPa (every 5 or 10 MPa). An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.7 · 10⁻³ g · cm⁻³, was used to perform these measurements. The experimental density data were fitted with the Tait-like equation with low standard deviations. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.     

Phase equilibria of the 0.8H2O-0.2C5H12 system within the temperature range of 303–684 K at pressures up to 60 MPa

Thermodynamic properties of a binary system containing of 0.2 mass fractions of C₅H₁₂ and 0.8 mass fractions of H₂O over the density and temperature ranges 87–713.68 kg/m³ and 303–684 K at pressures up to 60 MPa were studied experimentally using the constant volume piezometer method. Phase equilibrium lines and critical points of the system were obtained.     

Measurements of (p, ρ, T) properties for isobutane in the temperature range from 280 K to 440 K at pressures up to 200 MPa

Measurements of (p, ρ, T) properties for isobutane in the compressed liquid phase have been obtained by means of a metal-bellows variable volumometer in the temperature range from 280 K to 440 K at pressures up to 200 MPa. The volume-fraction purity of isobutane used was 0.9999. The expanded uncertainties (k = 2) of temperature, pressure, and density measurements have been estimated to be less than 3 mK, 1.5 kPa (p ⩽ 7 MPa), 0.06% (7 MPa < p ⩽ 50 MPa), 0.1% (50 MPa < p ⩽ 150 MPa), and 0.2% (p > 150 MPa), and 0.11%, respectively. In region more than 100 MPa at 280 K and 440 K, the uncertainty in density measurements rise up to 0.15% and 0.23%, respectively. The differences of the present density values at the same temperature between two series of measurements, in which the sample fillings are different, are within the maximum deviation of 0.09% in density, which is enough lower than the expanded uncertainty in density. Eight (p, ρ, T) measurements at the same temperatures and pressures as the literature values have been conducted for comparison. In addition, vapour pressures were measured at T = (280, 300) K. Moreover, the comparisons of the available equations of state with the present measurements are reported.     

Density and isothermal compressibility for two trialkylimidazolium-based ionic liquids at temperatures from (278 to 398) K and up to 120 MPa

In this paper, a densimeter based on vibrating tube principle is used to determine experimentally the density of 1-butyl-2,3-dimethylimidazolium tris(pentafluoroethyl)trifluorophosphate and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide at temperatures between (278.15 and 398.15) K and at pressures up to 120 MPa. The apparatus was calibrated by using water, vacuum and bromobenzene. The Tammann–Tait equation of state was used to correlate (p, T, ρ) results with standard deviations around 2 · 10⁻⁴ g · cm⁻³. Other volumetric properties, such as isothermal compressibility and isobaric thermal expansivity, were obtained from this equation. For each ionic liquid, the α_p isotherms present a crossing point within the experimental pressure range. Besides, the effect that the C2-methylation in the imidazolium cation provokes on density values is analyzed. The prediction ability of the group contribution methods of Gardas and Coutinho and Jacquemin et al. were tested with the experimental densities.     

(p, ρ, T) Properties for n-butane in the temperature range from 280 K to 380 K at pressures up to 200 MPa

The (p, ρ, T) properties for n-butane in the compressed liquid phase were measured by means of a metal-bellows variable volumometer in the temperature range from 280 K to 380 K at pressures up to 200 MPa. The mole fraction purity of the n-butane used in the measurements was 0.9997. The expanded uncertainties (k = 2) in temperature, pressure, and density measurements have been estimated to be less than ±3 mK; 1.4 kPa (p ⩽ 7 MPa), 0.06% (7 MPa < p ⩽ 50 MPa), 0.1% (50 MPa < p ⩽ 150 MPa), and 0.2% (p > 150 MPa); and 0.09%, respectively. In the region above100 MPa at T = 280 K and T = 440 K, the uncertainty in density measurements increases from 0.09% to 0.13% and 0.22%, respectively. Eight (p, ρ, T) measurements at the same temperatures and pressures as the literature values have been conducted for comparisons. In addition, comparisons of the available equations of state with the present measurements are reported.     

Solubility of methane in octane + ethanol at temperatures from 303.15 K to 333.15 K and pressures up to 12.01 MPa

Solubility of methane in octane + ethanol was measured at temperatures ranging from 303.15 K to 333.15 K and pressures ranging from 2.60 MPa to 12.01 MPa. Experimental data were analyzed using the Soave-Redlich-Kwong equation of state with three types of mixing rules, and the estimated average deviation from the experimental solubility data was less than 3.5 %.     

Speed of sound in liquid tetrachloromethane and benzene at temperatures from 283.15 K to 333.15 K and pressures up to 30 MPa

Speeds of sound in liquid tetrachloromethane and benzene were measured at temperatures from 283.15 K to 333.15 K and pressures up to about 30 MPa. The method used was a sing-around technique employing a fixed path acoustic interferometer operated at a frequency of 2 MHz. The probable uncertainty of the present results is less than ±0.2 percent taking into account the errors of ±20 mK for the temperature, and ±(3 to 5) kPa for the pressure measurements. Measured values are fitted to a polynomial equation as functions of temperature and pressure, and the reliability of the present results is discussed in the light of a comparison with reference data reported in the literature.     

Methane and carbon dioxide solubility in 1,2-propylene glycol at temperatures ranging from 303 to 423 K and pressures up to 12 MPa

This work reports solubility data of methane and carbon dioxide in 1,2-propylene glycol and the Henry's law constant of each solute in the studied solvent at saturation pressure. The measurements were performed at 303, 323, 373, 398 and 423.15 K and pressures up to 4.5 MPa for carbon dioxide solubility and pressures up to 12.1 MPa for methane solubility. The experiments were performed in an autoclave type phase equilibrium apparatus using the total pressure method (synthetic method). All investigated systems show an increase of gas-solubility with the increase of pressure. A decrease of carbon dioxide solubility with the increase of temperature and an increase of methane solubility with the increase of temperature was observed. From the variation of solubility with temperature, partial molar enthalpy and entropy change of the solute for each mixture were calculated.     

Solubility of methane and carbon dioxide in ethylene glycol at pressures up to 14 MPa and temperatures ranging from (303 to 423) K

This work reports solubility data of methane and carbon dioxide in ethylene glycol and the Henry’s law constant of each solute in the studied solvent at saturation pressure. The measurements were performed at (303, 323, 373, 398, and 423.15) K and pressures up to 6.3 MPa for mixtures containing carbon dioxide and pressures up to 13.7 MPa for mixtures containing methane. The experiments were performed in an autoclave type phase equilibrium apparatus using the total pressure method (synthetic method). All investigated systems show an increase of gas solubility with the increase of pressure. A decrease of carbon dioxide solubility with the increase of temperature and an increase of methane solubility with the increase of temperature was observed. From the variation of solubility with temperature, the partial molar enthalpy, and entropy change are calculated.     

On the viscosity Arrhenius temperature for methanol + N,N-dimethylformamide binary mixtures over the temperature range from 303.15 to 323.15 K

Excess properties calculated from literature values of experimental density and viscosity in N,N-dimethylformamide (DMF) + methanol (Met) binary mixtures (from 303.15 to 323.15 K) can lead us to test different correlation equations as well as their corresponding derivative properties. Inspection of the Arrhenius activation energy (E_a) and the enthalpy (ΔH*) of activation of viscous flow shows very close values; here, we can define partial molar activation energies E_a1 and E_a2 for N,N-DMF and Met, respectively, along with their individual contribution separately. Correlation between the two Arrhenius parameters of viscosity in all compositions shows existence of main distinct interaction behaviours delimited by particular mole fractions in N,N-DMF. In addition, we add that correlation between Arrhenius parameters reveals interesting Arrhenius temperature that is closely related to the vaporisation temperature in the liquid vapour equilibrium, and the limiting corresponding partial molar properties can permit us to estimate the boiling points of the pure components.     

The solubility of sulfur dioxide in aqueous solutions of sodium chloride and ammonium chloride in the temperature range from 313 K to 393 K at pressures up to 3.7 MPa: experimental results and comparison with correlations

The solubility of sulfur dioxide in aqueous solutions of single solutes sodium chloride and ammonium chloride was measured using a static method at temperatures from 313 K to 393 K and total pressures up to 3.7 MPa corresponding to gas molalities of up to 10 mol/kg. Similarily to the system sulfur dioxide–water, also in systems with sodium and ammonium chloride a second (sulfur dioxide-rich) liquid phase is observed at high sulfur dioxide concentrations. A model to describe the phase equilibria is presented. Experimental results are reported and compared to correlations.