Isobaric Thermal Expansion Research Articles

Density and refractive index measurements of transition-temperature mixture (deep eutectic analogues) based on potassium carbonate with dual hydrogen bond donors for CO2 capture

The transition-temperature mixture (TTM) is a new type of solvent and is known as a tuneable solvent similar to deep eutectic solvent (DES). The new type of solvent called ternary transition-temperature mixture (TTTM) was prepared to use for CO2 capture purposes. In this work, TTMs and TTTMs were prepared with potassium carbonate (PC) as a hydrogen bond acceptor (HBA) and three hydrogen bond donors (HBDs) such as glycerol (GL), ethylene glycol (EG) and 2-amino-2-methyl-1-3-propanediol (AMPD) known as a hindered amine (HA). Binary TTMs were PC-GL with mole ratios 1:10 and 1:16 and PC-EG with the same mole ratios. TTTMs were prepared by adding AMPD in binary TTMs such as PC-GL-AMPD 1:16:1 and PC-EG-AMPD 1:10:1. The experimental density and refractive index of all mixtures were measured at temperatures from 293.15 K to 343.15 K with an interval of 5 K. The effect of temperature, mole ratio, molar massand alkyl chain length on the properties was investigated. The molar volumes and isobaric thermal expansion were calculated using experimental density data. The experimental refractive index values were used to derive the specific refraction, molar refraction, free molar volume, electronic polarization and polarizability at several temperatures.

Exploring molecular interactions of binary mixture (dimethyl carbonate + benzyl benzoate): Measurements and correlation

To explore the type of interaction and its behavior with temperature in the binary mixture (dimethyl carbonate+benzyl benzoate), the density (ρ) and speed of sound (u) are measured for the whole mole fraction range at various temperatures T=(308.15, 313.15 and 318.15) K and at atmospheric pressure. Sign with magnitude of computed excess molar volume (VmE) was examined and detailed analysis elucidated not only prevalence of strong molecular interactions between molecules in study but also its variation with temperature. Further, strong interactions are well supported by partial and their excess partial molar volume (V¯m,V¯mE,V¯mE,∞). Furthermore, relative association (RA), Lennard-Jones repulsive power (n), excess isentropic compressibility (κsE), partial and their excess partial molar isentropic compressibility(K¯m, K¯mE), excess values of isobaric thermal expansion coefficient (αPE), isentropic compressibility (κsE), isothermal compressibility (kTE), intermolecular free length (LfE), acoustic impedance (ZE), surface tension (σSE), ultrasonic speed (uE) were evaluated and confirmed the conclusions made for VmE. By Redlich-Kister equation, coefficients with standard deviations are computed to excess parameters. VmE is correlated by Prigogine–Flory–Patterson (PFP) and Topology theories at 308.15K. Extended Langmuir model is examined for influence of the bulk mole fraction on surface tension. At T=308.15K, different derivatives of thermodynamic potentials, densities through Soave-Redlich-Kwong (SRK)/Peng-Robinson (PR) cubic equation of states, excess chemical potential and theoretical speeds using semi-empirical equations are evaluated. Using Hartmann–Balizar and Ballou non-linear equations, cohesive energy (ΔA), van der Wall's constants (a, b), distance of closest approach (d) are estimated through Sehgal's equations at all temperatures.

High pressure densities of two nanostructured liquids based on the bis(trifluoromethylsulfonyl)imide anion from (278 to 398) K and up to 120 MPa

In this article the volumetric behaviour of the nanostructured liquids, butyltrimethylammonium bis(trifluoromethylsulfonyl)imide and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, is reported. Density was measured in the temperature range (278.15–398.15) K up to 120 MPa with a high pressure densimeter based on the vibrating tube principle. Experimental densities were correlated as a function of temperature and pressure by means of the Tammann-Tait equation obtaining standard deviations lower than 3.5 × 10−4 g·cm−3. In addition, the isobaric thermal expansivity and the isothermal compressibility have been calculated from the Tait-like correlation. Furthermore, two group contribution methods proposed by Gardas and Coutinho and by Jacquemin et al. were applied to these fluids to analyse their prediction abilities for the high-pressure density.

Thermodynamic properties and sPC-SAFT modeling of 2-ethoxyethanol, 2-propoxyethanol and 2-butoxyethanol from T = (293.15–413.15) K and pressure up to 30 MPa

New experimental PρT data of three glycols ethers, namely, 2-ethoxyethanol, 2-propoxyethanol and 2-butoxyethanol were measured in a wide range of temperatures (293.15–413.15) K and pressures (0.1–30) MPa with a vibrating-tube densimeter. The experimental PρT data were correlated with the modified Tait equation. The study is completed with modeling in terms of the simplified perturbed-chain statistical associating fluid theory (sPC-SAFT) equation of state. The pure compound parameters of the sPC-SAFT equation are generally determined by fitting the equation to experimental saturated vapor pressure and liquid density data. In this work, by simultaneously minimizing the total objective function of temperature, pressure and density new correlation were developed to estimate the sPC-SAFT equation parameters with two association scheme for three glycols ethers including, 2-ethoxyethanol, 2-propoxyethanol and 2-butoxyethanol by using PρT data and with a fitting AAD% of 0.17 on average. The validity of the parameters and the employed association scheme were tested by the evaluation of densities and derivative properties such as isobaric thermal expansion coefficients, αP, isothermal compressibility, κΤ, isobaric heat capacities, CP, and speed of sound, u. All correlated/predicted results were compared with the modified Tait equation and experimental literature data. The obtained results showed that the sPC-SAFT equation of state, along with the proposed correlations, presents good results for modeling these glycols ethers.

Density, excess and limiting properties of (water and deep eutectic solvent) systems at temperatures from 293.15 K to 343.15 K

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, DES namely allyltriphenyl phosphonium bromide-diethylene glycol (ATPPB-DEG) was prepared by using three molar ratios of 1:4, 1:10 and 1:16 salt to HBD. The volumetric properties of aqueous DESs, such as density, molar volume, isobaric thermal expansion, apparent molar volume and apparent molar expansibility were reported at several temperatures from 293.15 to 343.15K. A mathematical equation, so-called Jouyban–Acree model (JAM), was used to correlate the experimental density and molar volume data of aqueous solution of DESs with respect to the concentration and temperature. The results disclosed that this model is an accurate and reliable model for the prediction of aqueous DES properties. The excess properties, such as excess molar volume and excess isobaric thermal expansion were reported and fitted to two different equations. In order to calculate the limiting apparent molar volume values, the apparent molar volume values were fitted into a Redlich–Mayer equation. By applying the Hepler equation, it was found that DESs with molar ratios of 1:4 and 1:10 are as structure-maker solutes, while the DES 1:16 is a structure-breaking solute in aqueous solutions at different temperatures.

Modeling Thermodynamic Properties of Propane or Tetrahydrofuran Mixed with Carbon Dioxide or Methane in Structure-II Clathrate Hydrates

A sound knowledge of thermodynamic properties of sII hydrates is of great importance to understand the stability of sII gas hydrates in petroleum pipelines and in natural settings. Here, we report direct molecular dynamics (MD) simulations of the thermal expansion coefficient, the compressibility, and the specific heat capacity of C3H8, or tetrahydrofuran (THF), in mixtures of CH4 or CO2, in sII hydrates under a wide, relevant range of pressure and temperature conditions. The simulations were started with guest molecules positioned at the cage center of the hydrate. Annealing simulations were additionally performed for hydrates with THF. For the isobaric thermal expansion coefficient, an effective correction method was used to modify the lattice parameters, and the corrected lattice parameters were subsequently used to obtain thermal expansion coefficients in good agreement with experimental measurements. The simulations indicated that the isothermal expansion coefficient and the specific heat capacity of...

Experimental and prediction of volumetric properties of aqueous solution of (allyltriphenylPhosphonium bromide—Triethylene glycol) deep eutectic solvents

Deep eutectic solvents (DESs) are derived from two or more salts as the hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs). In this work, DES namely allyltriphenylphosphonium bromide- triethylene glycol (ATPPB-TEG) was prepared by using three molar ratios; i.e.,1:4, 1:10, and 1:16 of salt to HBDs. The volumetric properties of aqueous mixture of DESs, such as density, molar volume, isobaric thermal expansion, apparent molar volume and apparent molar expansibility were reported at several temperatures from 293.15 to 343.15K. A mathematical equation, namely Jouyban–Acree model (JAM), was used to correlate the experimental density and molar volume data. Furthermore, in order to calculate the limiting apparent molar volume values, the apparent molar volume values were fitted into a Redlich–Mayer equation. By applying Hepler equation, it was found that DESs 1:4 and 1:10 are as structure-maker solutes, while DES 1:16 is a structure-breaking solute in aqueous solutions.

Quasiharmonic analysis of protein energy landscapes from pressure-temperature molecular dynamics simulations

Positional fluctuations of an atom in a protein can be described as motion in an effective local energy minimum created by the surrounding protein atoms. The dependence of atomic fluctuations on both temperature (T) and pressure (P) has been used to probe the nature of these minima, which are generally described as harmonic in experiments such as x-ray crystallography and neutron scattering. Here, a quasiharmonic analysis method is presented in which the P-T dependence of atomic fluctuations is in terms of an intrinsic isobaric thermal expansivity αP and an intrinsic isothermal compressibility κT. The method is tested on previously reported mean-square displacements from P-T molecular dynamics simulations of lysozyme, which were interpreted to have a pressure-independent dynamical transition Tg near 200 K and a change in the pressure dependence near 480 MPa. Our quasiharmonic analysis of the same data shows that the P-T dependence can be described in terms of αP and κT where below Tg, the temperature dependence is frozen at the Tg value. In addition, the purported transition at 480 MPa is reinterpreted as a consequence of the pressure dependence of Tg and the quasiharmonic frequencies. The former also indicates that barrier heights between substates are pressure dependent in these data. Furthermore, the insights gained from this quasiharmonic analysis, which was of the energy landscape near the native state of a protein, suggest that similar analyses of other simulations may be useful in understanding such phenomena as pressure-induced protein unfolding.

High Pressure Volumetric Properties of the Binary Mixtures Di-isopropyl Ether + 2,2,4-Trimethylpentane

New experimental density data for binary mixtures of di-isopropyl ether + 2,2,4-trimethylpentane over the full composition range are reported between 293.15 K and 393.15 K, and for pressures from 0.1 MPa up to 140 MPa. To perform these measurements, a vibrating tube densitometer was used and calibrated with an uncertainty of 3.5 × 10–4 g·cm–3. The experimental density data were fitted with a Tait-like equation. From experimental data, excess volumes have been calculated as well as the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.

Atomistic insights into the thermodynamics, structure, and dynamics of ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate via molecular dynamics study

Molecular dynamics (MD) simulations were performed to compute the properties of the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate, [hmim][PF6], at three different temperatures (298, 323, and 348K) and atmospheric pressure. Thermodynamic, structural, and dynamical properties, such as average density, isobaric thermal expansion coefficient, isothermal compressibility factor, radial distribution function (RDF), spatial distribution function (SDF), mean square displacement (MSD) and velocity autocorrelation function (VACF) were computed and interpreted. The ionic self-diffusion coefficients were calculated using both the Einstein and Green–Kubo formulas and it was found that the cation diffuses faster than the anion and contributes more in the electric current. The ionic self-diffusion coefficients obtained from the Green–Kubo method agreed reasonably well with the experimental data in compared to the Einstein method. Also, the self-diffusion coefficients obtained from the two methods were used to calculate the ionic conductivity from the Nernst–Einstein equation. The effects of the system size and simulation run-time on determining diffusivity using the Einstein method were also investigated. The RDFs show that anions interact preferentially with the cation ring especially in direction of the acidic hydrogen atom of the imidazolium ring. This interaction was identified as hydrogen bonding interaction and observed using SDF.

Viscosity and density measurements on liquid n-tetradecane at moderately high pressures

The main aim of the work is to study the viscosity and density of compressed normal tetradecane in the region of pressures from saturation to 10 MPa, where the available literature data are scarce. New measurements of the viscosity of n-tetradecane (n-C14) along eight isotherms in the range (283–358) K and at pressures up to 70 MPa, have been performed using the vibrating wire technique in the forced mode of operation. Density measurements have also been performed along nine isotherms in the temperature range from (283 to 373) K and pressures from (0.1 to 70) MPa. The vibrating wire viscosity results were correlated with density, using a modified hard-spheres scheme. The root mean square (rms) deviation of the data from the correlation is less than 0.32% and the maximum absolute relative deviation is less than 1.0%. The expanded uncertainty of the present viscosity data is estimated as ±1.5% at a 95% confidence level. The density results were correlated with the temperature and pressure using a modified Tait equation. The expanded uncertainty of the present density data is estimated as ±0.2% at a 95% confidence level. The isothermal compressibility and the isobaric thermal expansion were calculated by differentiation of the modified Tait equation. The uncertainties of isothermal compressibility and the isobaric thermal expansion are estimated to be less than ±1.7% and ±1.1%, respectively, at a 95% confidence level. The results are compared with the available literature data.

Thermophysical characterization of aqueous deep eutectic solvent (choline chloride/urea) solutions in full ranges of concentration at T = (293.15–323.15) K

Deep eutectic solvents (DESs) as a novel generation of green solvents have been used in several processes in academia and technology in the recent years. In this study, it was measured some thermophysical properties of aqueous solutions of the deep eutectic solvents (choline chloride/urea) in full ranges concentration of DES at T=(293.15–323.15)K. The densities, speeds of sound, refractive indices, and viscosities of the investigated systems have been measured by precise methods and those results used to calculate various thermodynamic and transport properties including the excess molar volumes (VE), the partial molar volumes (V¯m,1 and V¯m,2), the excess isobaric thermal expansions (αpE), the excess molar isentropic compressibility (κs,mE), the viscosity deviations (Δη), and the deviation of molar refraction (ΔRD). These variations of properties were discussed in terms of solute-solvent interactions occurring between the components of the solutions. Eyring theory of vicos flow is used to calculate excess activation functions (ΔG#E), ΔH#E and ΔS#E of DES solutions.

Volumetric properties of 2,5-dimethylfuran in mixtures with octane or dodecane from 293 K to 393 K and pressures up to 70 MPa

We report isothermal volumetric properties for two binary systems constituted by 2,5-dimethylfuran (x)+a linear alkane (1−x); octane and dodecane are the representative alkanes. Compressed liquid densities were obtained via oscillating period measurements in two commercial vibrating U-shaped tube densimeters. The experiments were performed within the pressure and temperature intervals from 0.1MPa to 70MPa and from 293K to 393K, respectively. Properties for these binary systems were measured at x=(0.1154, 0.2999, 0.4967, 0.6962, 0.8924) for 2,5-dimethylfuran+octane mixtures; whereas, compositions measured for 2,5-dimethylfuran+dodecane mixtures were x=(0.1995, 0.4067, 0.4972, 0.6053, 0.8045). Experimental density data were correlated by using the Tammann-Tait equation. Thermodynamic derived properties were calculated from the same equation, and their dependence on pressure, temperature and composition was discussed. These properties were isobaric thermal expansivity, isothermal compressibility, thermal pressure coefficient, internal pressure and mixing molar volume.

The reactants equation of state for the tri-amino-tri-nitro-benzene (TATB) based explosive PBX 9502

The response of high explosives (HEs), due to mechanical and/or thermal insults, is of great importance for both safety and performance. A major component of how an HE responds to these stimuli stems from its reactant equation of state (EOS). Here, the tri-amino-tri-nitro-benzene based explosive PBX 9502 is investigated by examining recent experiments. Furthermore, a complete thermal EOS is calibrated based on the functional form devised by Wescott, Stewart, and Davis [J. Appl. Phys. 98, 053514 (2005)]. It is found, by comparing to earlier calibrations, that a variety of thermodynamic data are needed to sufficiently constrain the EOS response over a wide range of thermodynamic state space. Included in the calibration presented here is the specific heat as a function of temperature, isobaric thermal expansion, and shock Hugoniot response. As validation of the resulting model, isothermal compression and isentropic compression are compared with recent experiments.

Novel halogen free hydrophobic trioctylammonium-based protic ionic liquids with carboxylate anions: Synthesis, characterization, and thermophysical properties

A three novel hydrophobic trioctylammonium-based protic ionic liquids (PILs) with 3,4-dimethylbenzoate, salicylate, and nonanedioate anions were synthesized and their structure were confirmed using nuclear magnetic resonance, elemental analysis and Fourier transform infrared spectroscopy. The three synthesized PILs were liquids at room temperature. The thermal properties were determined using thermogravimetric analyzer and differential scanning calorimetry. Density, viscosity, surface tension, and refractive index were measured for the synthesized PILs at temperature between 293.15 and 363.15K at atmospheric pressure and as expected, it was found to decrease with increasing temperature. The density measurements were correlated as a linear function of temperature, and the viscosities were fitted to a Vogel-Fulcher-Tamman equation. The density measured values were used to calculate the molar volume, molecular volume, standard entropy, lattice potential energy and the isobaric thermal expansion coefficients, whilst the surface excess energy and entropy were calculated using the measured surface tension data. The di-cationic nonanedioate PIL was found to have higher viscosity, surface tension, heat capacity and onset decomposition temperature.

Investigation of solute-solvent interactions in {1-butyl-3-methyl imidazoliumBis(trifluoromethylsulfonyl)imide + dimethylcarbonate} mixture using physicochemical properties

Physical properties, such as density (ρ), speed of sound (u) and refractive index of [Bmim][NTf2], DMC and their binary mixtures are measured over the whole composition range as a function of temperature between (303.15 and 323.15) K at atmospheric pressure. Experimental values are used to calculate excess values of molar volumes (VmE)/partial molar volumes (V‾mE)/partial molar volumes at infinite dilution (V‾mE,∞)/isentropic compressibility (κsE)/free length (LfE), speed of sound (uE) and isobaric thermal expansion coefficient (αPE) for the binary mixture. These excess properties are fitted to the Redlich-Kister equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates strong intermolecular interactions and the interaction increases with the increase in temperature. Further, through physicochemical properties, an attempt for calorimetric excess chemical potential using different equations is computed at T=308.15K. The present investigation also comprises of evaluation of the acoustic non-linearity parameter (B/A) in the mixtures and calculation of cohesive energy (ΔA), Van der Wall’s constants (a, b), distance of closest approach (d). The presence of strong interactions is further supported by IR spectroscopy and the Prigogine–Flory–Patterson (PFP) theory.

Physicochemical properties and spectral studies of the 1,3-butanediol + dimethyl sulfoxide binary system at T = (293.15–318.15) K

ABSTRACTThis work reports experimental dynamic viscosity (η) and density (ρ) for 1,3-butanediol (BTD) (1) and dimethyl sulfoxide (DMSO) (2) binary systems at T = (273.15–318.15) K and p = 0.1 MPa. From the experimental ρ and η data, the excess molar volumes () values, viscosity deviation (∆η) values, partial molar volumes ( and ) values, apparent molar volume (Vφ,1 and Vφ,2) values, excess free energies of activation () values and isobaric thermal expansion coefficient (αp) values were, respectively, obtained. After that, a Redlich–Kister equation was used to fit , ∆η and values. The mixtures exhibited positive with a maximum at x1 = 0.55, which became more pronounced after temperature increased. The obtained standard deviations (σ) values were compared with literature data and conclusion about application modus was drawn. From FTIR, UV–vis, FTIR and NMR spectral information, intermolecular interaction between BTD and DMSO was systemically explored.

Volumetric and viscometric properties of amino acids in aqueous myo-inositol solution at T = (293.15 to 323.15) K and p = 0.101 MPa

Densities and viscosities of glycine, L-alanine, L-valine, L-threonine and L-arginine in aqueous (0.1–0.5) mol·kg−1myo-inositol solutions were measured at T=(293.15, 303.15, 313.15 and 323.15) K and p=0.101MPa. The volumetric properties such as the apparent molar volume (Vφ), the limiting partial molar volume (Vφ0), the limiting partial molar volumes of transfer (ΔtrVφ0), the limiting apparent molar expansibility (E20), Hepler's constant and the isobaric thermal expansion coefficient (α2) were calculated through density. The viscometric properties such as the B-coefficient, the free energies of activation per mole of solvent (Δμ10≠) and solute (Δμ20≠) were obtained from the experimental viscosity data. The derived parameters hydration number and solvation number were also calculated through apparent molar volume and B-coefficient. From the volumetric and viscometric properties, the solute-solute and solute-solvent interactions in the studied systems were analyzed on the basis of co-sphere overlap model and transition state theory. Finally, the group contribution method was applied to calculate the contribution of (NH3+, COO−), CH2, OH and CNHNHNH2 of amino acids to Vφ0, B-coefficient and Δμ20≠.

New Experimental Data and Modeling of Glymes: Toward the Development of a Predictive Model for Polyethers

The design and optimization of industrial processes relies on the availability of robust and accurate models and equations of state (EoSs). Considering the further advancement of the use of soft-SAFT (one version of statistical associating fluid theory) EoS, toward its implementation in industrial processes, a methodology to determine the molecular model and transferable molecular parameters of glymes is discussed herein. In addition to the commonly used vapor pressure and saturated liquid densities, the description of the temperature and pressure effect is improved by including one additional density–pressure and one isothermal compressibility isotherm (both at 323 K) for the molecular parameter optimization. For the guiding of the selection and optimization of the soft-SAFT EoS molecular model and parameters, new high-pressure density data (pρT) and derived properties, such as isothermal compressibility and isobaric thermal expansion, of eight glymes (glycol ethers) have been determined in wide ranges o...

Volumetric, acoustic, optical and spectroscopic studies of binary mixtures of the ionic liquid, 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide and diethyl carbonate

ABSTRACTThe properties, density, speed of sound and refractive index of ‘IL’ [Bmim][NTf2], diethyl carbonate and their binary mixtures are measured over the whole composition range as a function of temperature between 303.15 and 323.15 K at atm. pressure. These values are used to calculate the excess molar volumes, excess partial molar volumes, partial molar volumes at infinite dilution, excess isentropic compressibility, free length, speeds of sound and isobaric thermal expansion coefficient for the mixture. Various rules were used to predict the refractive indices and the data have been compared with the experimental results. These excess properties are fitted to the Redlich–Kister type equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates strong intermolecular interactions and the interaction increases with the increase in temperature. This was further supported by IR spectroscopy. In addition, analysis of data of the mixture was done through the Prigogine–Flory–Patterson theory.