Isobaric Expansion Research Articles

Temperature and concentration dependence of volumetric properties of (tetrahydrofuran + methyl acrylate, or + ethyl acrylate, or + n-butyl acrylate, or + tert-butyl acrylate) binary mixtures

The densities, ρ of binary mixtures of tetrahydrofuran (THF) with methyl acrylate (MA), ethyl acrylate (EA), n-butyl acrylate (n-BA) and tert-butyl acrylate (t-BA) over the entire composition range including those of pure liquids, were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15, 318.15)K and atmospheric pressure. From the experimental results, the excess molar volume, VmE, excess molar isobaric expansion, Ep,mE, partial molar volumes, V‾m,1 and V‾m,2, excess partial molar volume, V‾m,1E and V‾m,2E, excess partial molar isobaric expansions, E‾p,m,1E and E‾p,m,2E over the whole composition range; partial molar volumes, V‾m,1° and V‾m,2°, and excess partial molar volumes, V‾m,1°E and V‾m,2°E of the components at infinite dilution have been calculated. The variations of these volumetric properties with composition and temperature are discussed in terms of the molecular interactions prevailing in these mixtures. It is observed that the THF-acrylate interactions in these mixtures follow the order: MA>EA>n-BA>t-BA. The values of VmE were also calculated theoretically by using Prigogine-Flory-Patterson (PFP) theory and the results were found in good agreement with the experimental findings.

Thermophysical study of 2-acetylthiophene: Experimental and modelled results

Several thermophysical properties have been studied for 2-acetylthiophene: (i) vapour pressure was determined at temperatures within 336.16–445.02 K; (ii) density, speed of sound, static permittivity, refractive index, surface tension, and kinematic viscosity were measured at p = 0.1 MPa and at temperatures from 278.15 K (or 283.15 K for the refractive index) to 338.15 K; (iii) volumetric properties were also determined at temperatures in the (283.15–338.15) K range and at pressures up to 65.0 MPa. From these experimental values, different derivative properties have been calculated such as enthalpy of vaporization, isobaric expansibility, isothermal and isentropic compressibility, dipole moment, entropy and enthalpy of surface formation, and dynamic viscosity. All experimental properties were correlated and the results were explained through the intermolecular interactions. Moreover PC-SAFT EoS was used to model the thermodynamic behaviour of the compound. Finally, this EoS combined with the Density Gradient Theory allowed obtaining the influence parameter for the surface tension of 2-acetylthiophene.

Determination of the thermodynamic properties of water from the speed of sound

Thermodynamic properties of compressed liquids may be obtained from measurements of the speed of sound by means of thermodynamic integration subject to initial values of density and isobaric specific heat capacity along a single low-pressure isobar. In this paper, we present an analysis of the errors in the derived properties arising from perturbations in both the speed-of-sound surface and the initial values. These errors are described in first order by a pair of partial differential equations that we integrate for the example case of water with various scenarios for the errors in the sound speed and the initial values. The analysis shows that errors in either the speed of sound or the initial values of density that are rapidly oscillating functions of temperature have a disproportionately large influence on the derived properties, especially at low temperatures. In view of this, we have obtained a more accurate empirical representation of the recent experimental speed-of-sound data for water [Lin and Trusler, J. Chem. Phys. 136, (2012) 094511] and use this in a new thermodynamic integration to obtain derived properties including density, isobaric heat capacity and isobaric thermal expansivity at temperatures between (253.15 and 473.15) K at pressures up to 400MPa. The densities obtained in this way are in very close agreement with those reported by Lin and Trusler, but the isobaric specific heat capacity and the isobaric expansivity both differ significantly in the extremes of low temperatures and high pressures.

Synthesis and thermophysical properties of pyrrolidonium based ionic liquids and their binary mixtures with water and DMSO at T = (293.15 to 333.15) K

In this work, two pyrrolidonium based ionic liquids namely N-methyl pyrrolidonium bisulfate ([NMP][HSO4]) and pyrrolidonium bisulfate ([PY][HSO4]) were synthesized and characterized by 1H NMR spectroscopy technique. The experimental density, speed of sound, viscosity and conductivity have been measured in the temperature range of (293.15–333.15) K and at 0.1MPa pressure. From the experimental data, derived thermodynamic properties such as molecular volume, standard entropy, crystal energy, isobaric expansion coefficient, molecular free length and molar conductivity have been calculated. Empirical equations, Newton–Laplace equation, Vogel–Tammann–Fulcher equation and Walden equation were presented to understand the nature of the pure ionic liquids. Further, experimental measurements for density and speed of sound of binary mixtures of [PY][HSO4] with water and/or DMSO were studied as a function of IL concentration at various temperatures and apparent molar properties were calculated using Redlich-Mayer equation. Finally, experimental and derived thermodynamic properties were explored to understand the intermolecular interactions of studied systems.

A Review and Extension of Existing Consistency Tests for PVT Data From a Laboratory

SummaryAny calculation of the phase behavior of a reservoir fluid from the reservoir to the refinery requires prior knowledge of the fluid's physical properties. Because the necessary pressure–volume–temperature (PVT) experiments are not free of systematic and random errors, the engineer involved in using fluid models is advised to check the fluid properties determined by the laboratory before application in their simulation models. This paper is designed to provide a guideline for how to obtain reliable and consistent PVT data from a laboratory. In addition, it reviews and extends existing consistency checks with a critical focus on the Y-function. Its applicability is limited to the two-phase region of a reservoir fluid. As it turns out, the Y-function can be applied not only to the constant-composition experiment (CCE) of black oil (BO), but also for the same experiment with a gas-condensate (GC). Furthermore, we show that the Y-function is a useful tool for the evaluation of the differential-liberation experiment (DLE, BO) and the constant-volume depletion (CVD, GC). In all these cases, the shape of this function is close to a straight line. After the Y-function is properly set up, it is possible to estimate the quality of the CCE and the DLE for the BO case and CCE and CVD for the GC. The second part of the review is devoted to explaining the role of the solution gas in BO, because both the formation volume factor (FVF) Bo and the oil viscosity μo are affected by the amount of solution gas. Helpful functions for estimates and consistency checks are given. In addition, estimates for the isothermal compressibility and the isobaric expansion of oil are presented.

Densities and Apparent Molar Volumes of Aqueous Solutions of Li2SO4 and LiCF3SO3 at Temperatures from 293 to 343 K

Densities of aqueous solutions of lithium sulfate (Li2SO4) and lithium trifluoromethanesulfonate (LiCF3SO3) at solute molalities ranging from 0.05 to 2.7 or 9.6 mol·kg–1, respectively, have been measured by vibrating-tube densimetry over the temperature range 293.15 ≤ T/K ≤ 343.15 at 0.1 MPa pressure. The apparent molar volumes (Vϕ) of Li2SO4(aq) and LiCF3SO3(aq) derived from these data were fitted using an extended Redlich–Rosenfeld–Meyer equation. The Vϕ values for the two systems exhibit quite different dependences on concentration and temperature, as do the isobaric expansibilities. A combination of the present and literature data reveals that the densities for Li2SO4(aq) given in standard compilations are unreliable at low concentrations. Comparison of the present results with literature data for related salts shows that Vϕ(LinX) and Vϕ(NanX) exhibit a crossover at ≈0.5 mol·kg–1 for both systems, similar to those observed previously for other lithium and sodium salts. Consideration of an appropriate ...

Effect of tetrabutylammonium hydrogen sulphate on the Solution thermodynamics of thiamine hydrochloride in aqueous solutions

The densities and viscosities of thiamine hydrochloride (vitamin-B1) in aqueous tetrabutylammonium hydrogen sulphate (Bu4NHSO4) solutions with several molal concentrations (mBu4NHSO4=0.000, 0.005, 0.010, 0.015 and 0.020mol⋅kg‐1) of Bu4NHSO4 were determined at T=(298.15, 308.15 and 318.15) K under atmospheric pressure. Using experimental data apparent molar volume (φV), standard partial molar volume (φV0), the slope (SV), standard isobaric partial molar expansibility (φE0) and its temperature dependence(∂φE0/∂T)P, the viscosity B-coefficient and solvation number (Sn), etc., were determined. Viscosity B-coefficients were further utilized to obtain the free energies of activation of viscous flow per mole of the solvents (Δμ10≠) and of the solute (Δμ20≠). Effects of molality, solute structure and temperature on all these parameters were analyzed in term of ion-ion and ion-solvent interactions; results revealed that the solutions are characterized predominantly by ion-solvent interactions and thiamine hydrochloride behaves as a long-range structure maker.

Densities at high pressures and derived properties of thiophenes

This contribution reports the densities in wide temperature (from 283.15 to 338.15K) and pressure (from 0.1 to 65.0MPa) ranges of four members of the thiophene family (thiophene, 2-methylthiophene, 3-methylthiophene and 2,5-dimethylthiophene). These densities have been satisfactorily correlated by means of the TRIDEN equation. From these data, several derived properties as isobaric expansibility, isothermal compressibility, and internal pressure have been estimated. Using all these properties, interesting information about molecular organization can be deduced.

Standard volumetric characteristics of N-dimethyl-substituted bicyclic bisureas (glycolurils) in water at T = (278.15 to 318.15) K and p ~ 0.1 MPa

Densities of aqueous solutions of achiral cis-dimethylglycoluril (2,8-DMGU) and chiral (in the racemic form) trans-dimethylglycoluril (2,6-DMGU) were measured using a hermetically sealed vibrating-tube densimeter, with an uncertainty of ~1×10−5g∙cm−3, at T=(278.15, 288.15, 298.15, 308.15, and 318.15) K and p=(99.6±0.4) kPa. The solution molality was ranged from (0.037 to 0.396) mol·kg−1 for aqueous 2,6-DMGU and from (0.046 to 0.202) mol·kg−1 for aqueous 2,8-DEGU. The standard (at infinite dilution) molar volumes and isobaric molar expansibilities for the specified N-dimethyl-substituted heterocyclic compounds in water were computed and discussed in comparison with previously derived results for the equimolecular 2,4-dimethylglycoluril (2,4-DMGU) whose isomeric molecules contain simultaneously both the unsubstituted and fully methylated five-membered rings. It was established that the compared glycoluril-derivatives are the prevailingly structure-breaking solutes in water despite of presence of two methyl groups in each of heterocyclic molecules. In other words, the hydrophobic hydration effect is being less pronounced than the hydrophilic hydration or H-bonding effect (via amide and carbonyl groups). The temperature-dependent behavior of packing-related hydration effects was described taking into account the structural (stereochemical) features of a solute molecule.

Temperature and composition dependences of volumetric properties of (water + 1,2-propanediol) binary system

The experimental data on the density of aqueous solutions of 1,2-propanediol over the whole concentration range are performed at different temperatures (278.15, 288.15, 298.15, 308.15, 323.15 and 333.15) K and atmospheric pressure. The density was measured also for the diluted solutions at temperatures from 274.15 to 283.15K with 1K step for examination of 1,2-propanediol influence on the temperature of maximal density (TMD) of water. The apparent molar volume of the mixture components, Vφ,i, the partial molar volumes, Vi, and the partial molar isobaric expansions, Ep,i, were calculated depending on concentration and temperature. The following volumetric parameters were determined for infinite diluted solutions: the partial molar volumes of the mixture components, Vi∞, and the partial molar isobaric expansions, EP,i∞. The results obtained were discussed in terms of solute-solvent and solute-solute interactions. The literature data on the above volume properties of (water+1,2-propanediol) mixture were reviewed. The character of disturbing influence of 1,2-propanediol on the structure of water was established using different approaches to analysis of the volumetric properties. It was shown that the criteria of hydrophobicity examined resulted in contradictory conclusions. Therefore those criteria are to be considered simultaneously for drawing reasonable conclusions.

On the compressibility of liquid metals

The adiabatic compressibilities κS of 64 liquid metallic elements at their melting points were obtained from the densities ρ and speeds of sound u reported in the literature. The isothermal compressibilities were obtained from the κS values by means of the molar volumes V, isobaric expansibilities αP, and isobaric molar heat capacities CP from the literature. The ratios γ=κT/κS=CP/CV yielded the isochoric molar heat capacities CV. The products κTσ, using surface tension data from the literature, were calculated and shown to diminish linearly with increasing cohesive energy densities.

Some thermophysical properties of methanol and aqueous methanol mixtures at sub- and supercritical conditions

Expressions for the composition dependence of the critical constants of mixtures or water and methanol are presented as are expressions of the vapor pressure, the molar enthalpy of vaporization, and the molar volume of methanol along its saturation curve. The internal pressure of saturated methanol is compared with it cohesive energy density, reflecting the diminishing strength of its intermolecular hydrogen bonding as the temperature is increased. Thermophysical properties (molar volumes, isobaric expansibilities, isothermal compressibilities, and internal pressures) of mixtures of methanol and water at subcritical temperatures at saturation and at the fixed pressures of 7 and 20MPa have been calculated and are presented in a table. The self- and mutual association of water and methanol in their mixtures at sub-critical temperatures is examined.

Volume properties of liquid mixture of {water (1) + ethylenediamine (2)} over the temperature range from 274.15 to 333.15 K at atmospheric pressure

The density of {water (1)+ethylenediamine (2)} binary mixture was measured over the whole concentration range at temperatures from 274.15 to 333.15K and at atmospheric pressure. The experimental values were used to calculate a whole number of the mixture parameters such as the excess molar volumes, molar isobaric expansions, apparent and partial molar volumes, partial molar isobaric expansions, limiting partial molar volumes and limiting partial molar isobaric expansions both of water and ethylenediamine. The extremal dependence of the partial molar volumes of the mixture components was observed; the mixture excess molar volumes were negative at all temperatures and depended weakly on temperature. The concentration dependences of the partial molar volumes of the mixture components were very similar to the dependences for aqueous mixtures of the nonelectrolytes with hydrophobic properties. The mixture molar isobaric expansion increased with ethylenediamine concentration over the whole concentration range. The concentration dependences of partial molar isobaric expansions of both water and ethylenediamine were rather complex and correlated with the mixture melting diagram.

Solution properties and taste behavior of lactose monohydrate in aqueous ascorbic acid solutions at different temperatures: Volumetric and rheological approach

The densities and viscosities of lactose monohydrate in aqueous ascorbic acid solutions with several molal concentrations m=(0.00–0.08)molkg−1 of ascorbic acid were determined at T=(298.15–318.15)K and pressure p=101kPa. Using experimental data apparent molar volume (ϕV), standard partial molar volume (ϕV0), the slope (SV∗), apparent specific volumes (ϕVsp), standard isobaric partial molar expansibility (ϕE0) and its temperature dependence (∂ϕE0/∂T)P, the viscosity B-coefficient and solvation number (Sn) were determined. Viscosity B-coefficients were further employed to obtain the free energies of activation of viscous flow per mole of the solvents (Δμ10≠) and of the solute (Δμ20≠). Effects of molality, solute structure and temperature and taste behavior were analyzed in terms of solute-solute and solute-solvent interactions; results revealed that the solutions are characterized predominantly by solute-solvent interactions and lactose monohydrate behaves as a long-range structure maker.

Densities and Viscosities of Polyhydroxy Solutes in Aqueous Tetraethylammonium Bromide Solutions at Different Temperatures

Infinite-dilution standard partial molar volumes, V2°, and the Jones–Dole viscosity B-coefficients of some saccharides and their polyols, (−)-d-arabinose, (+)-d-arabitol, (+)-d-xylose, xylitol, (−)-l-sorbose, d-sorbitol, (+)-d-galactose, galactitol, (+)-d-glucose, and (+)-d-maltose monohydrate, have been obtained in aqueous (0.05, 0.5, 1.0, and 2.0) mol·kg–1 tetraethylammonium bromide (Et4NBr) solutions from apparent molar volumes, V2,ϕ, and relative viscosities, ηr data, respectively, at (288.15, 298.15, 308.15, and 318.15) K under atmospheric pressure, p = 0.1 MPa. The corresponding transfer parameters (ΔtV2° and ΔtB) along with isobaric expansion coefficients, (∂V2°/∂T)P, their second-order derivatives (∂2V2°/∂T2)P, pair (VAB, ηAB), and triplet (VABB, ηABB) volumetric, and rheological interaction coefficients have been determined, because these parameters are sensitive to structural changes occurring in solutions due to temperature and concentration changes. Pentoses, hexoses, and their polyols exhibit...

Thermophysical properties of the thiophene family

In this contribution, we have studied the thermophysical properties of three members of the thiophene family (thiophene, 2-methylthiophene, and 2,5-dimethylthiophene) at atmospheric pressure in a wide temperature range. Density, speed of sound, dynamic viscosity, surface tension, and static permittivity have been determined from T = 278.15 to T = 338.15 K at atmospheric pressure, while the refractive index has been obtained under atmospheric pressure in a temperature range from 283.15 to 338.15 K. Vapour pressures of these compounds have been also measured. Finally, several useful properties like isobaric expansibility, isentropic compressibility, molar refraction, and dipolar moment have been calculated from the experimental data.

Thermophysical properties of seawater: A review and new correlations that include pressure dependence

In a previous paper, the authors have given correlations for seawater thermophysical properties as functions of temperature and salinity, but only for near atmospheric pressures. Seawater reverse osmosis (SWRO) systems operate routinely at pressures of 6MPa or more; however, experimental data for seawater properties at elevated pressures (P=0.1–12MPa) are limited to a salinity of 56g/kg. To accurately model and design SWRO and thermal desalination systems, a reliable method of estimating the effect of pressure on seawater properties is required. In this work, we present this method and new correlations for seawater thermophysical properties that are valid within the range: t=0–120°C, S=0–120g/kg, and P=0–12MPa. Seawater isothermal compressibility data, available until a salinity of 56g/kg, were used to develop a correlation for compressibility that is extrapolated to 160g/kg. Thermodynamic identities were then used to develop accurate pressure dependent correlations for seawater: density, isobaric expansivity, specific heat capacity, enthalpy, entropy and Gibbs energy. New correlations were proposed for seawater: vapor pressure, thermal conductivity and activity of water. Recent work on seawater surface tension and osmotic coefficient were reviewed. Uncertainty bounds were calculated for each correlation.

Volumetric and viscometric studies of nicotinic acid in aqueous solutions of sodium malonate at T = (298.15–318.15) K

Densities and viscosities for the solutions of nicotinic acid in aqueous sodium malonate solutions with several molalities (msodium malonate=0.000, 0.005, 0.010, 0.015 and 0.020mol·kg-1) of sodium malonate were determined at T=(298.15–318.15)K and at pressure p=101kPa. Apparent molar volume (ϕV standard partial molar volume (ϕV0 the slope (SV∗), standard isobaric partial molar expansibility (ϕE0) and its temperature dependence (∂ϕE0/∂T)P, the viscosity B-coefficient and solvation number (Sn), etc., were determined. Using the experimental data viscosity B-coefficients were further utilized to obtain the free energies of activation of viscous flow per mole of the solvents (Δμ10≠) and of the solute (Δμ20≠). Effects of molality, solute structure and temperature on all these parameters were analyzed in term of ion–ion and ion–solvent interactions; results revealed that the solutions are characterized predominantly by ion–solvent interactions and nicotinic acid behaves as a long-range structure maker.

Experimental and modeled volumetric behavior of linear and branched ethers

Ethers are known to be suitable octane enhancers for gasoline whose combustion process is optimized in direct-ignition spark-ignition engines, where the fuel is directly injected in the chamber at pressures up to 20 MPa. To know and predict the thermodynamic behavior of the fluid will be very convenient to study these processes. In this work, we report density experimental data for nine linear and branched ethers (butyl methyl, methyl tert-butyl, butyl ethyl, ethyl tert-butyl, dipropyl, diisopropyl, dibutyl, dipentyl, and diisopentyl) in the pressure and temperature range from 0.1 to 65 MPa and from 283.15 to 333.15 K (for methyl tert-butyl ether the temperature range was 283.15–323.15 K). From our measurements, we studied the effect of temperature and pressure on density by calculating isobaric expansibility and isothermal compressibility. Other properties such as internal pressure and solubility parameter, which describe the degree of cohesion of the molecules, were obtained. We compared the experimental and calculated data with the literature and a good agreement is found. Finally, we modeled the phase and volumetric behavior using two Equations of State: PC-SAFT and CPA. The needed parameters were obtained from literature or by fitting of their vapor liquid equilibrium and density data; several linear correlations for these parameters were found. Both EoS provided similar deviations in the density but PC-SAFT predicted better than CPA the phase equilibrium (saturation pressure and density) and the solubility parameter.

Transition in fluctuation behaviour of normal liquids under high pressures

We explore the behaviour of the inverse reduced density fluctuations and the isobaric expansion coefficient using α,ω-dibromoalkanes as an example. Two different states are revealed far from the critical point: the region of exponentially decaying fluctuations near the coexistence curve and the state with longer correlations under sufficiently high pressures. The crossing of the isotherms of the isobaric expansion coefficient occurs within the PVT range of the mentioned transition. We discuss the interplay of this crossing with the changes in molecular packing structure connected with the analysed function of the density, which represents inverse reduced volume fluctuations.