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.     

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.     

Solubility of carbon dioxide in aqueous solutions containing sodium acetate or ammonium acetate at temperatures from 313 to 433 K and pressures up to 10 MPa

The solubility of carbon dioxide was measured in aqueous solutions containing the single salts sodium acetate and ammonium acetate corresponding to salt molalities in the liquid phase of about 4 mol/kg and 6 mol/kg in the temperature range from 313 K to 433 K at total pressures up to 10 MPa. Pitzer's semiempirical model for the excess Gibbs energy of aqueous electrolyte solutions is used to correlate the new data. Experimental results are reported and compared to correlations.     

Solubility of oxygen in aqueous sodium carbonate solution at pressures up to 10 MPa

The solubilities of oxygen in 0.2, 0.5, 0.7 and 1.0 M Na₂CO₃ solution have been measured at 300.15 K and under pressures up to 10 MPa using a magnetically stirred autoclave and a direct sampling technique. The accuracy of apparatus was verified by duplicating the solubility of oxygen in pure water in literature. The experimental data of the solubility of oxygen in aqueous sodium carbonate solution were shown that the solubility of oxygen increases with increasing pressure and decreases with increasing salt concentration due to salting-out effect. The experimentally measured data were satisfactorily compared with the predicted values by our model based on non-primitive mean spherical approximation (MSA) and perturbation theory.     

Hydrogen adsorption on microporous materials at ambient temperatures and pressures up to 50 MPa

High surface area microporous adsorbents are often proposed as potential hydrogen storage materials, although typically at 77?K and less than 5?MPa. In this study, we focus on conditions more suitable for automotive applications by investigating the storage capacities of microporous materials at 298?K and at pressures up to 50?MPa. In an effort to derive trends within and across material classes, we examined a wide range of materials with varying microstructures including the activated carbons AX-21, KUA-5, and MSC-30; a zeolite templated carbon; a hypercrosslinked polymer; and the Metal Organic Frameworks MOF-177, IRMOF-20, MIL-53, ZIF-8, and Cu₃(btc)₂. The peak excess adsorption of these materials ranged from 0.8–1.8?wt.%, although many did not reach their maximum capacity even at high pressures. However, the total volumetric storage gains over compressed hydrogen gas were quite low and, in many cases, negative. In addressing ambient temperature adsorption at significantly higher pressures than previously reported, our data confirms and extends the range of validity of several existing DFT calculations. Furthermore, our data suggest that, for both activated carbons and MOFs, factors other than specific surface area govern ambient temperature adsorption capacity. Contrary to some reports, the high fractions of sub-nanometer pores in some of the investigated MOFs did not appear to enhance the excess adsorption even at high pressures. For on-board applications with ambient temperature storage, significant enhancements to the attractive force at the materials’ surface are required, beyond merely increasing specific surface area, or for MOFs, tuning of pore sizes.     

Partial molar volumes of organic solutes in water. VI.o-Chlorophenol andp-chlorophenol at temperatures from 298 K to 573 K and pressures up to 30 MPa

Density data for dilute aqueous solutions of two isomeric chlorohydroxybenzenes (chlorophenols) obtained in the temperature range 298.15 K to 573.15 K and at either atmospheric pressure, or at pressures close to the saturated vapour pressure of water, and at pressures up to 30 MPa are presented together with partial molar volumes calculated from the experimental data. The data were obtained using either a high-temperature and high-pressure flow vibrating-tube densimeter for measurements at elevated pressures or a commercial vibrating-tube cell DMA 602HT for measurements at atmospheric pressure.     

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.     

Solubility of Itaconic Acid in Aqueous Ethanol Mixtures from 278.15 K to 333.15 K

Data on corresponding solid?Cliquid equilibrium of itaconic acid in binary aqueous ethanol solutions are essential for industrial design and further theoretical studies. Using the analytical stirred-flask method, the solubility of itaconic acid in pure water solvent and mixed solvents were measured over the temperature range from 278.15 to 333.15 K at atmospheric pressure. The effect of solvent composition and temperature on the solubility is discussed. The solubility data were correlated with the Combined Nearly Ideal Binary Solvent/Redlich (CNIBS/R-K) model. The solubility measured in this study can be used for the itaconic acid purification or optical resolution by the preferential crystallization procedure.     

Compressed liquid densities of 1-butanol and 2-butanol at temperatures from 313 K to 363 K and pressures up to 25 MPa

(p, ρ, T) properties were determined in liquid phase for 1-butanol and 2-butanol at temperatures from 313 K to 363 K and pressures up to 25 MPa using a vibrating tube densimeter. The uncertainty is estimated to be lower than ±0.2 kg · m⁻³ for the experimental densities. Nitrogen and water were used as reference fluids for the calibration of the vibrating tube densimeter. Experimental densities of 1-butanol and 2-butanol were correlated with a short empirical equation 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 were reported. Published densities of 1-butanol and 2-butanol are compared with values calculated with the BWRS EoS using the parameters obtained in this work. The experimental data determined here are also compared with available correlations for 1-butanol and 2-butanol.     

Partial molar volumes of organic solutes in water. X. Benzene and toluene at temperatures from (298 to 573) K and at pressures up to 30 MPa

Density data for dilute aqueous solutions of benzene and toluene are presented together with partial molar volumes at infinite dilution calculated from the experimental data. The measurements were performed at temperatures from (298.15 to 573.15) K and at pressures close to the saturated vapor pressure of water, at 30 MPa and at pressures between these limits. The data were obtained using a high-temperature high-pressure flow vibrating-tube densimeter.     

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.     

Solubility study of methane,carbon dioxide and nitrogen in ethylene glycol at elevated temperatures and pressures

An experimental apparatus was built for measuring the gas solubility at high temperature and pressure. An auxiliary system was developed to keep the system pressure constant while the liquid samples are withdrawn. Solubility of methane, carbon dioxide and nitrogen in ethylene glycol (EG) was determined experimentally at temperatures of 323.15, 373.15 and 398.15 K and pressures up to 40 MPa. SRK equation of state was used to calculate the phase equilibria for those polar asymmetric systems.     

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.     

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.     

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.