Compressed liquid densities and excess molar volumes for (CO2 + 1-pentanol) binary system at temperatures from 313 to 363 K and pressures up to 25 MPa

Measurements of compressed liquid densities for 1-pentanol and for {CO₂ (1) + 1-pentanol (2)} system were carried out at temperatures from 313 K to 363 K and pressures up to 25 MPa. Densities were measured for binary mixtures at 10 different compositions, x₁ = 0.0816, 0.1347, 0.3624, 0.4651, 0.6054, 0.7274, 0.8067, 0.8573, 0.9216, and 0.9757. A vibrating tube densimeter was used to perform density measurements using two reference calibration fluids. The uncertainty is estimated to be better than ±0.2 kg · m^?3 for the experimental density measurements. For each mixture and for 1-pentanol, the experimental densities were correlated using an explicit volume equation of six parameters and an 11-parameter equation of state (EoS). Excess molar volumes were determined for the (CO₂ + 1-pentanol) system using 1-pentanol densities calculated from the 11-parameter EoS and CO₂ densities calculated from a multiparameter reference EoS.     

Densities and derived thermodynamic properties of 1-heptanol and 2-heptanol at temperatures from 313 K to 363 K and pressures up to 22 MPa

Experimental densities were determined in liquid phase for 1-heptanol and 2-heptanol at temperatures from 313 K to 363 K and pressures up to 22 MPa using a vibrating tube densimeter. Water and nitrogen were used as reference fluids for the calibration of the vibrating tube densimeter. The uncertainties of the experimental measurements in the whole range of reported data are estimated to be ±0.03 K for temperature, ±0.008 MPa for pressure, and ±0.20 kg · m^?3 for density. The experimental data are correlated using a short empirical equation of six parameters and the 11-parameter Benedict–Webb–Rubin–Starling equation of state (BWRS EoS) using a least square optimization. Statistical values to evaluate the different correlations are reported. Published density data of 1-heptanol are compared with values calculated with the 6-parameter equation using the parameters obtained in this work. The experimental data determined here are also compared with an available correlation for 1-heptanol. Densities of 2-heptanol at high pressure were not found in the literature and the data reported here represent the first set of data reported in the literature. Isothermal compressibilities and isobaric thermal expansivity are calculated using the 6-parameter equation for both alcohols within uncertainties estimated to be ±0.025 Gpa^?1 and ±4 × 10^?7 K^?1, respectively.     

Density measurements of liquid 2-propanol at temperatures between (280 and 393) K and at pressures up to 10 MPa

Liquid densities for 2-propanol have been measured at T = (280, 300, 325, 350, 375, and 393) K from about atmospheric pressure up to 10 MPa using a vibrating tube densimeter. The period of vibration has been converted into density using the Forced Path Mechanical Calibration method. The R134a has been used as reference fluid for T ? 350 K and water for T > 350 K. The uncertainty of the measurements is lower than ±0.05%. The measured liquid densities have been correlated with a Starling BWR equation with an overall AAD of 0.025%. The same BWR equation agrees within an AAD lower than 0.2% with the experimental values available in the literature over the same temperature and pressure range.     

Viscosity of aqueous Na2SO4 solutions at temperatures from 298 to 573 K and at pressures up to 40 MPa

Viscosities of nine (1.5, 3, 5, 7, 10, 15, 20, 23, and 26) mass% of aqueous Na₂SO₄ solutions have been measured in the liquid phase with a capillary flow technique. Measurements were made at five isobars 0.1, 10, 20, 30, and 40 MPa. The range of temperatures was from 298.15 to 573.5 K. The total uncertainty of viscosity, pressure, temperature, and concentration measurements was estimated to be less than 1.5%, 0.05%, 15 mK, and 0.015%, respectively. The reliability and accuracy of the experimental method was confirmed with measurements on pure water for four selected isobars 5, 10, 20, and 40 MPa and at temperatures between 296.7 and 573.7 K. The experimental and calculated values from IAPWS (International Association for the Properties of Water and Steam) formulation for the viscosity of pure water show excellent agreement within their experimental uncertainty (AAD = 0.41%). The temperature, pressure, and concentration dependences of the relative viscosity (η/η₀) where η₀ is the viscosity of pure water are studied. The values of the viscosity A-, B-, and D-coefficients of the extended Jones–Dole equation for the relative viscosity (η/η₀) of aqueous Na₂SO₄ solutions as a function of temperature are studied. The maximum of the B-coefficient near the 323 K isotherm has been found. The behavior of the concentration dependence of the relative viscosity of aqueous Na₂SO₄ solutions is discussed in terms of the modern theory of transport phenomena in electrolyte solutions. The derived values of the viscosity A- and B-coefficients were compared with the results predicted by Falkenhagen–Dole theory of electrolyte solutions and calculated with the ionic B-coefficient data. Different theoretical models for the viscosity of electrolyte solutions were stringently tested with new accurate measurements on aqueous Na₂SO₄. The quality and predictive capability of the various models was studied. The measured values of viscosity were directly compared with the data reported in the literature by other authors.     

Liquid density of biofuel mixtures: (Dibutyl ether + 1-butanol) system at pressures up to 140 MPa and temperatures from (293.15 to 393.15) K

This work reports new experimental density data (445 points) for binary mixtures of (dibutyl ether + 1-butanol) over the composition range (five compositions; 0.15 ? dibutyl ether mole fraction x ? 0.85), from (293.15 to 393.15) K (every 20 K), and for 15 pressures from (0.1 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 a Tait-like equation with low standard deviations. Excess volumes have been calculated from the experimental data and fitted by the Redlich–Kister equation. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.     

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 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 HFE-7200 and HFE-7500 from T = (283 to 363) K at pressures up to 100 MPa

The liquid densities of HFE-7200 (1-ethoxy-1,1,2,2,3,3,4,4,4-nonafluorobutane, CAS Registry Number: 163702-05-4) and HFE-7500 (3-ethoxyperfluoro(2-methylhexane), CAS Registry Number: 297730-93-9) have been measured over the temperature range from (283 to 363) K and pressures up to 100 MPa by using a high pressure vibrating-tube densimeter. R134a has been used as a reference fluid to validate the densimeter. The uncertainty of each obtained datum was estimated, and the maximum expanded uncertainty with a level of confidence of 0.95 (k = 2) of density measurement for HFE-7200 and HFE-7500 were 0.04% and 0.03%, respectively. The measured liquid densities were correlated with the modified Tait equation and the maximum deviation is less than 0.03%. The isothermal compressibility and isobaric thermal expansivity were also calculated.     

Compressed liquid densities of ethane-propane mixtures between 10 and 49°C at pressures up to 9.6 MPa

Densities of compressed liquid ethane-propane mixtures are reported at five temperatures between 10.00 ad 48.90°C. For each isotherm the data cover eight compositions ranging between 30 and 95 mol% ethane at pressures up to 9.65 MPa. The excess volumes derived from the data are negative, extremely dependent on temperature and pressure, and can represent up to a 50% correction to the ideal mixture volume.     

Compressed liquid densities for the (n-heptane + n-decane) and (n-octane + n-decane) systems from T = (313 to 363) K

Densities (p, ρ, T, x₁) of two binary n-alkane systems are reported from T = (313 to 363) K in the compressed liquid phase up to 25 MPa over the whole range of composition. The binary mixtures {x₁n-heptane + (1 ? x₁)n-decane} and {x₁n-octane + (1 ? x₁)n-decane} were prepared at compositions of (x₁ = 0.0531, 0.2594, 0.5219, 0.777, 0.952), and (x₁ = 0.0616, 0.2801, 0.5314, 0.7736, 0.9623), respectively. A measuring system based on a vibrating tube densimeter, DMA HPM from Anton Paar with data acquisition system was developed in order to obtain experimental densities. Water and nitrogen were used as reference fluids to calibrate the densimeter. Experimental methodology was checked by comparing the n-heptane and n-decane densities against multi-parameter equations proposed in the literature. Differences between both sets of data show a maximum deviation of 0.07%. Excess molar volumes, isothermal compressibility and isobaric thermal expansivity were computed from experimental densities.     

Thermodynamic properties of mixtures of N-methyl-2-pyrrolidinone and methanol at temperatures between 298.15 K and 343.15 K and pressures up to 60 MPa

We report measurements of the speed of sound in mixtures of N-methyl-2-pyrrolidinone and methanol at temperatures between 298.15 K and 343.15 K and at pressures up to 60 MPa. The measurements were made using a dual path pulse-echo apparatus operating at a frequency of 5 MHz. We have also measured the isobaric specific heat capacity of each mixture as a function of temperature at ambient pressure, by means of a Setaram DSC III microcalorimeter. The experimental results have been combined with literature data for the density of the same mixtures as a functions of temperature at ambient pressure to obtain the density, isobaric specific heat capacity, and other thermodynamic properties at temperatures between 298.15 K and 343.15 K and at pressures up to 60 MPa. Detailed comparisons with the literature data are presented.     

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.     

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.     

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.     

(P, Vm, T) Measurements of (octane + 1-chlorohexane) at temperatures from 298.15 K to 328.15 K and at pressures up to 40 MPa

Densities were measured for the liquid octane and 1-chlorohexane, and for nine of their mixtures at four temperatures between 298.15 K and 328.15 K and at pressures up to 40 MPa. An apparatus for density measurements of liquids and liquid mixtures whose main part is a high-pressure vibrating-tube densimeter working in a static mode was used for the measurement. The density data were fitted to the Tait equation and the isothermal compressibilities were calculated with the aid of this equation. Excess molar volumes were also computed from the densities and fitted to the Redlich–Kister equation.     

Measurements of the viscosity of carbon dioxide at temperatures from (253.15 to 473.15) K with pressures up to 1.2 MPa

The viscosity of carbon dioxide was measured over the temperature range T = (253.15 to 473.15) K with pressures up to 1.2 MPa utilizing a new rotating-body viscometer. The relative expanded combined uncertainty (k = 2) in viscosity (including uncertainties of temperature and pressure) was (0.20 to 0.41)%. The instrument was specifically designed for measurements at low gas densities and enables measurements of the dynamic viscosity at temperatures between T = 253.15 K and T = 473.15 K with pressures up to 2 MPa. For carbon dioxide, the fluid specific measuring range with regard to pressure was limited to 1.2 MPa due to the formation of disturbing vortices inside the measuring cell at higher pressures. The model function for the viscosity measurement was extended in such a way that the dynamic viscosity was measured relative to helium. Therefore, the influence of the geometry of the concentric cylindrical system inside the measuring cell became almost negligible. Moreover, a systematic offset resulting from a small but inevitable eccentricity of the cylindrical system was compensated for. The residual damping, usually measured in vacuum, was calibrated in the entire temperature range using viscosity values of helium, neon and argon calculated ab initio; at T = 298.15 K recommended reference values were used. A viscosity dependent offset of the measured viscosities, which was observed in previously published data, did not occur when using the calibrated residual damping. The new carbon dioxide results were compared to other experimental literature data and to the correlation, which is currently considered the reference for viscosities of carbon dioxide.