Experimental Density Data Research Articles

Excess properties and isothermal vapour-liquid equilibrium data for the ((toluene + pyridine)) system from 343 K to 383 K

Isothermal vapour-liquid equilibrium (VLE) data for the ((toluene + pyridine)) system has been measured at four temperatures from approximately 343 K to 383 K, using a dynamic-analytic apparatus. The densities of ((toluene + pyridine)) mixtures were also measured from 298 K to 363 K using an Anton Paar DMA-5000 densitometer. The vapour-liquid phase equilibrium data were modelled by the γ-Φ approach and the Non-Random Two-Liquid and UNIQUAC activity coefficient models. The consistency of the experimental isothermal VLE data were checked by the area and point tests. The experimental density data were modelled using an 8-parameter empirical correlation which allowed for the simultaneous representation of temperature and liquid composition. The experimental data were used to determine the excess properties for volume, Gibbs energy, enthalpy and entropy. The excess volume was modelled using Redlich-Kister polynomials.

Studies on Bed Density in a Gas-Vibro Fluidized Bed for Coal Cleaning.

Dry coal beneficiation has played a vital role during the initial stage of coal cleaning in recent years. Successful utilization of a gas–solid fluidized bed for >6 mm coal cleaning motivates scholars to explore the possibility of fine coal cleaning using dry beneficiation methods. In this study, pulsed flow was introduced into a fluidized bed to optimize bubble behavior, thus improving the density stability. The equation of minimum fluidization velocity (Umfp) in a gas-vibro fluidized bed for coal preparation was investigated theoretically. An equation has been proposed for predicting Umfp while considering changes in the friction coefficient (Cf) in the gas-vibro fluidized bed. Based on two-phase theory, the correlation of bed density was determined by analyzing the bubble behavior in the gas-vibro fluidized bed. The theoretical bed density was then compared with experimental data of the bed density and separation density. The predicted bed density in monodisperse and binary dense medium systems was found to be consistent with the experimental results. Overall, the equation of bed density is suitable for estimating the separation density in the gas-vibro fluidized bed.

Acid-catalysed Al2O3 sol and its gel material: influence of HNO3 content and stability

A series of Al2O3 sols were prepared by HNO3 catalysis of aluminum isopropoxide (AIP), using different molar ratios of HNO3/AIP (nH). The changes in sol densities, viscosities, refractive indices, stability and particle sizes were reported. Derived properties such as Gibbs energies (ΔG*) and the reaction rate constant (k) have been calculated from the experimental density and viscosity data. The phase-chemical structures of Al2O3 materials were characterized using Fourier transform infrared (FTIR) and X-ray diffraction (XRD) measurement. The results show that, when the molar ratio of HNO3/AIP is 0.25, the prepared Al2O3 sol was transparent, uniform and stable, and the sol average particle size gets the minimum. The chemical structure of the non-calcined Al2O3 gel material is dominated by Al–O–H and Al–O bonds. After calcination at 350 °C, the Al–O–H bond will break and is transformed into Al–O bonds, and the phase structure is changed from γ-AlOOH to γ-Al2O3.

Thermodynamic characterization of deep eutectic solvents at high pressures

Despite the large spectrum of applications being reported for DESs over the last decade, their thermodynamic characterization is often neglected, hindering a better understanding of their nature, and the development of accurate and robust thermodynamic models to describe them, essential for the conceptual and design stages of new industrial processes.This work aims at decreasing such a gap in literature by reporting new experimental density and viscosity data in wide temperature and pressure ranges for the three archetypal DESs of cholinium chloride, as hydrogen bond acceptor, combined with either ethylene glycol, glycerol, or urea, as hydrogen bond donor. The experimental data measured in this work were then correlated using the Perturbed Chain - Statistical Associating Fluid Theory equation of state coupled with the Free Volume Theory to assess the performance of existing coarse-grained models when applied to the description of DESs. The modelling results obtained highlight the limitation of the existing models, since a correct prediction of DES density could not be achieved, reinforcing the need for viable alternative approaches for the development of coarse-grained models that are appropriate for the thermodynamic modelling of DESs.

Solubility and Liquid Density of Ammonia/Athabasca Bitumen Mixtures at Temperatures up to 463 K: Measurements and Modeling

We report the experimental data of ammonia solubility in Athabasca bitumen measured at different temperatures and pressures ranging from 348 to 463 K and 1 to 4 MPa, respectively. The liquid-phase density of ammonia-saturated bitumen was measured for the samples that were taken during solubility measurements. The experimental data for ammonia solubility in bitumen were modeled using the Peng–Robinson equation of state. The volume-shift parameters of ammonia were tuned to represent the experimental density data of ammonia-saturated bitumen with an average absolute relative deviation percent (AARD%) of 0.218%. Also, tuning the binary interaction coefficient between ammonia and bitumen allowed the prediction of solubility data with an AARD of 8.537%. The data and the tuned model find applications in the reservoir modeling of solvent-aided thermal recovery of bitumen and heavy oil.

Investigation of the Constitutive Model of W/PMMA Composite Microcellular Foams.

Investigating the constitutive relationship of a material can provide better understanding of the mechanical properties of a material and has an irreplaceable effect on optimizing the performance of a material. This paper investigated a constitutive model for tungsten/polymethyl-methacrylate (W/PMMA) composite microcellular foams prepared by using melt mixing and supercritical carbon dioxide foaming. The stress-strain relationships of these foams with different W contents were measured under static compression. The elastic modulus and compressive strength values of the foams were remarkably greater than those of the pure PMMA foams: at a W content of 20 wt %, these values were increased by 269.1% and 123.9%, respectively. Based on the Maxwell constitutive model, the relevant coefficients were fitted according to the experimental data of different relative densities and W contents in quasi-static compression. According to the numerical relationships between the relevant coefficients and the relative densities and W contents, the quasi-static mechanical constitutive model of W/PMMA composite microcellular foams with W contents of 0~60 wt % and relative densities of 0.15~0.55 were predicted. This study provided basic data for the optimal design of the W/PMMA composite microcellular foams and proposed a method for investigating the mechanical properties of composite microcellular foam materials.

Thermophysical characterization of sorbitol and 1–ethyl–3–methylimidazolium acetate mixtures

In this study, the solubility of a sugar alcohol (sorbitol) in 1–ethyl–3–methylimidazolium acetate was measured experimentally at various temperatures. Excess Gibbs energy models were utilized for modeling of solubility. Additionally, the thermophysical properties including density and viscosity of the binary mixtures of ionic liquid and sorbitol were measured. With the application of experimental data the apparent molar volumes at infinite dilution Vϕ0, the apparent molar isobaric expansibility Eϕ0 and Hepler's constants were calculated. It was found that sorbitol behaves as structure-breaker in the ionic liquid. Moreover, the applicability of local composition models for correlation of the experimental solubility and density data was further investigated. Additionally, Arrhenius–Andrade and Vogel–Tamman–Fulcher equations were applied for correlation of the viscosity measurements.

Тhermodynamic properties of isobutane/mineral compressor oil and isobutane/mineral compressor oil/fullerenes C60 solutions

In present study a new experimental data for the saturated liquid density and saturated vapor pressure along the boiling line for the solutions of the ”natural” refrigerant isobutane (R600a) with mineral compressor oil and solutions of R600a/compressor oil/fullerenes C60 is presented. Moreover, a new experimental data on the specific isobaric heat capacity, enthalpy and entropy along the boiling line for the R600a/compressor oil solutions is reported. Experimental data of the two-phase isochoric heat capacity was obtained for different compressor oil fraction in the refrigerant in the temperature range from 260 to 330 K. Obtained information was used to calculate the caloric properties of the R600a/compressor oil solutions. In addition, an influence of fullerene C60 on the specific isobaric heat capacity of mineral oil was examined. The measurements of the heat capacity for the R600a/compressor oil solutions, pure compressor oil and compressor oil containing fullerenes C60 were performed using an experimental setup that implements a direct heating method in adiabatic calorimeter. In addition, the heat capacity of oil and oil containing fullerenes C60 have been measured using differential scanning calorimetry. Finally, the heat capacity increase for the compressor oil with the additives of 0.0020 kg kg−1 of fullerenes C60 was observed.

Thermodynamic, DFT and molecular dynamics studies of intermolecular interactions between 2-methoxyaniline and N- substituted amide mixtures

Abstract The experimental data of density(ρ) and speed of the sound(u) of 2-methoxyaniline and N-alkyl amides binary liquid mixtures have been evaluated at temperatures T = (303.15 to 318.15) K. Values of excess molar volume ( V m E ), excess isentropic compressibility ( k s E ), excess partial molar volumes ( V ¯ m , 1 E , V ¯ m , 2 E ) , and excess partial molar volumes at infinite dilution ( V ¯ m , 1 E , ∞ , V ¯ m , 2 E , ∞ ) over the whole composition range have been calculated by using the density and the speed of sound measurements. The calculated excess parameters were used to discuss the intermolecular interactions. A quantum mechanical approach was performed in gas phase and classical molecular dynamic simulations were done in liquid phase to study the intermolecular interactions in self and cross-associated complexes. The details of experimental, quantum mechanical and classical molecular dynamic methods are used to investigate the formation of a hydrogen-bonded network between 2-methoxyaniline and N-alkyl amide mixtures.

Measurements and modeling of the density of rocket propellant RP-2 at temperatures to 573 K and pressures to 100 MPa

Liquid rocket propellants are subject to wide ranges of temperature and pressure when flowing through high performance liquid rocket engines. For example, as rocket propellant (RP) is used for regenerative cooling, near-wall fluid temperatures can exceed 700 K. The pressure can reach as high as 100 MPa when exiting the fuel pump. Therefore, accurate thermophysical property data, particularly density, are needed to accurately model the flow in rocket engines using computational fluid dynamics (CFD) and other engineering design tools. In this work, we report the density of two RP-2 samples at temperatures to 573 K and pressures to 100 MPa. A high-temperature, high-pressure (HTHP) variable-volume, windowed densimeter is used to determine the density. The experimental density data are satisfactorily correlated by the modified Tait equation that provides a means for interpolating the density within the experimental conditions investigated in this study. The HTHP perturbed-chain statistical associating fluid theory (PC-SAFT), Peng-Robinson (PR), and HTHP volume-translated PR equations of state are used to model RP-2 density over the entire temperature and pressure ranges.

Investigation of Physico-chemical Properties for the 1-Butyl-3-methylimidazolium Tetrafluoroborate ([Bmim][BF4])–Diethylenetriamine (DETA) System for CO2 Capture

This paper presents the experimental values of densities, viscosities and refractive indices for 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4])–diethylenetriamine (DETA) mixtures over the entire composition range and temperature range 298.15–333.15 K. The physico-chemical properties such as excess molar volume, partial molar volume, partial molar volume at infinite dilution, apparent molar volume, apparent molar volume at infinite dilution, isobaric thermal expansion coefficient and excess isobaric thermal expansion coefficient were calculated from the experimental density data. The excess Gibbs energy and excess entropy of flow were determined from the viscosity data using Eyring’s theory of rate process. The specific interactions between molecules in mixtures were explained by analyzing the behavior of the thermodynamic excess/deviation properties. To determine the correlating accurately with the utilized models including the Redlich–Kister, modified Graber, Lorentz–Lorenz and McAllister equations, the adjustable parameters and standard deviations were determined. Moreover, the qualitative analysis of these properties was further legitimized with Fourier-transform infrared (FTIR) spectroscopic studies.

Effects of Polygonum cuspidatum on expression of IL-6, IL-2 and AMPK in synovial membrane of collagen induced arthritis rats

To investigate the nature and class of association forces between the pure liquids and their liquid mixtures, we have been analyzed with excess thermodynamic properties, spectroscopic and computational techniques. Although, the thermodynamic parameters such as excess volume (VE), isentropic compressibility (ks) and excess isentropic compressibility (ksE) have been calculated using the experimental data of density (ρ) and speeds of sound (u) of o-cresol with 1-alkanols (C3–C8) namely, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol and 1-octanol at different temperatures from 25 to 40 °C with interval of 5 °C and at 0.1 MPa. The calculated excess and deviation functions have been fitted to the Redlich-Kister polynomial equation and the results have been analyzed in terms of molecular interactions and structural effects. However, the FT-IR data strongly supports the presence of intra- and inter molecular interactions between component molecules in the liquid mixtures through changing the stretching vibrational frequency of various functional groups of pure liquids. In addition, the hydrogen bonding features between o-cresol with different 1-alkanols were examined by using a molecular modeling program with the help of density functional theory (DFT - B3LYP), the optimized geometries, bond characteristics, natural bond orbital (NBO) and interaction energies of pure components and their complexes have been analyzed theoretically to recognize the nature and strength of interactions between o-cresol and 1-alkanols.

Development of Generalized Correlations for Thermophysical Properties of Light Hydrocarbon Solvents (C1–C5)/Bitumen Systems Using Genetic Programming

Accurate modeling of thermophysical properties of solvent/bitumen mixtures is critical for proper design and implementation of thermal- and solvent-based bitumen recovery processes. In this study, three generalized correlations were developed for prediction of solubility, density, and viscosity of light hydrocarbon/bitumen mixtures. The generalized correlations were developed using symbolic regression based on genetic programming and employing a 10-year set of comprehensive phase behavior experimental studies conducted under the SHARP research program on solvent-aided thermal recovery of bitumen. The data set comprised Surmont, JACOS, Mackay River, and Cold Lake bitumen samples and five light hydrocarbon solvents including methane, ethane, propane, n-butane, and n-pentane. The developed correlations are valid for gaseous solvents. Finally, the developed correlations for solubility, density, and viscosity were validated against a large data set of experimental measurements collected from the literature. The validation demonstrates that the developed correlations are able to accurately predict the available experimental data of solubility, density, and viscosity reported in the literature.

Thermophysical study of binary mixtures of 1-butyl-3-methylimidazolium nitrate ionic liquid + alcohols at different temperatures

New experimental data of density and viscosity for the binary mixtures of 1-butyl-3-methylimidazolium nitrate ([Bmim][NO3]) with + 2-propanol, 2-butanol and 2-pentanol are reported over the entire range of mole fraction at T = (293.15–323.15) K. To elucidate possible intermolecular interactions between the chemical species present in solutions, the excess molar volume, VmE thermal expansion coefficient, α excess thermal expansion coefficient, αE the isothermal coefficient of excess molar enthalpy, ∂HmE/∂PT,x partial molar volume, Vi¯ and deviation in viscosity, Δη were calculated. The excess molar volume of the binary mixture is negative over the entire mole fraction range and becomes more negative with increase in the temperature. Deviation in the viscosity is negative over the whole range of composition and decreases with increasing temperature. The obtained excess molar volume and deviation in viscosity were fitted to the Redlich–Kister polynomial equation. The experimental results have been discussed regarding molecular interactions and the formation of complex between unlike molecules. Influences of temperature and carbon chain length of alcohols were discussed.

Liquid Phase Density, Sound Speed, and Vapor Pressure of Linear Alkanes Using the Mattedi–Tavares–Castier Equation of State

This work assesses the ability of the Mattedi–Tavares–Castier (MTC) equation of state (EOS) in representing the liquid phase density, sound speed, and vapor pressure of linear alkanes (C6–C20). It is found that its deviations from experimental data for liquid phase density, liquid phase sound speed, and vapor pressure are similar to, yet slightly higher than, those of the PC-SAFT EOS for the same compounds. Using only experimental data points at reduced pressures smaller than 20 for parameter fitting, a condition observed in most commercial chemical processes, leads to smaller deviations from the experimental values. Adopting for the lattice cell volume the value of 15 cm3/mol, which is the molar volume of the methylene group in the lattice-based UNIQUAC model, all the adjustable MTC EOS parameters follow regular trends with respect to the number of carbon atoms in the linear alkane chains. These parameters could be fitted to empirical expressions. When used, they produce deviations in pure-component liquid phase density, liquid phase sound speed, and vapor pressure equal to 0.6, 2.8, and 9.8%, respectively. The results for binary mixtures are generally in good agreement with the experimental data.

Comments on “Investigation of diverse interactions of amino acids (Asp and Glu) in aqueous dopamine hydrochloride with the manifestation of the catecholamine molecule recognition tool in solution phase”

A polemic is given regarding several of the calculated numerical values in the published paper. The authors' calculated apparent molal volumes for aspartic acid and glutamic acid dissolved in aqueous-dopamine hydrochloride cannot be obtained from the experimental density data and amino acid molalities given in the published paper. Differences in calculated values are much more evident at low amino acid concentrations.

PρT measurements and modelling of (n-decane + m-xylene) mixtures from 293.15 K to 363.15 K at pressures up to 60 MPa

In this work, the experimental measurements for liquid densities of n-decane and m-xylene binary mixtures were performed over the entire composition range with a high-pressure vibrating-tube densimeter. The range of temperatures for the present measurements was from 293.15 K to 363.15 K and the pressures were up to 60 MPa. The combined expanded uncertainty of the density measurements is estimated to be 0.001ρ with 0.95 confidence. Experimental density values were correlated by the modified Tammann-Tait equation. The simplified Perturbed Associating Fluid Theory (sPC-SAFT) and Cubic Plus Associated (CPA) equations of state (EoS) were applied to predict the densities of n-decane and m-xylene and their mixtures. Reasonably results were observed between the experimental data and calculated results for the two equations, and the deviation is less than 0.48% and 0.89% with sPC-SAFT and CPA EoS, respectively. In addition, excess molar volumes were determined from the experimental density data as well as from sPC-SAFT and CPA models. The effects of pressure and temperature on the excess molar volume were also discussed.

Thermophysical Properties of the Medium-Chain 1-Alkyl Halides in a Wide Range of Conditions: New Experimental Data and Predictions of CP-PC-SAFT and FT-EOS

This study reports experimental density and sound velocity data of 1-chloroheptane and 1-iodoheptane at 291.45 ≤ T ≤ 413.15 K and 1 ≤ P ≤ 1961 bar along with the atmospheric pressure liquid densiti...

Physicochemical approach to study the solute-solute and solute-solvent interactions of drug Levofloxacin hemihydrate in aqueous sorbitol solutions at different temperatures: Volumetric, acoustic and conductance studies

The interactions of third generation fluoroquinolone antibiotic drug Levofloxacin hemihydrate (LFH) with the naturally occurring polyol i.e. sorbitol as a function of temperature have been investigated by volumetric, acoustic and conductance methods. Densities, speeds of sound and conductance values of LFH (0.001–0.01 mol·kg−1) in water and aqueous sorbitol (0.002, 0.004 and 0.006 mol·kg−1) have been measured at different temperatures (300.15, 305.15, 310.15 and 315.15 K). The experimental density data was used to calculate apparent molar volume (ΦV), limiting apparent molar volume (ΦVo), Masson's coefficient (SV), partial molar expansibilities (ΦE0), transfer volume ΔtrΦVo and Hepler's constant ∂2ΦVo∂T2. From speed of sound data parameters like isentropic compression (βS), intermolecular free length (Lf), specific acoustic impedance (Z) and molar compressibility (W) were calculated. From conductance data specific conductance (Ҡ), molar conductance (Λm), limiting molar conductance (Λmo), Walden product (Λmoηo), dissociation constant (Kc) and activation energy (Ea) were calculated. The derived data has been discussed in terms of solute-solute and solute-solvent interactions. The positive values of ∂2ΦV0∂T2 and positive temperature coefficient of Walden product Λmoηo suggests that LFH acts as structure-maker in water and aqueous sorbitol systems.

Density and Derived Properties of Binary Mixtures Containing {2-(Dimethylamino)ethyl Methacrylate + Alcohols} at Temperatures from T = (293.15 to 313.15) K and Pressures of up to 35 MPa

In this study, experimental density data (ρ) for binary liquid mixtures containing {2-(dimethylamino)ethyl methacrylate (DMAEMA) + methanol, or + ethanol, or + 1-propanol, or + 1-butanol, or + 1-pentanol} have been measured over the entire composition range at temperatures from T = (293.15 to 313.15) K and pressures of up to 35 MPa. Density measurements were obtained using an Anton Paar DMA 4500 vibrating-tube densimeter coupled to an external Anton Paar DMA HP high-pressure measuring cell. The experimental results for density have been fit to the Tait–Tammann equation and used to calculate the isothermal compressibility (κT), the thermal expansion coefficient (αp), and the internal pressure (π). The excess molar volume (VmE) values have still been calculated and used to test the applicability of the extended real associated solution model (ERAS model) and the Prigogine–Flory–Patterson theory (PFP Theory). The thermodynamic results suggest that structural and chemical effects must outweigh physical effects.