Isobaric Thermal Expansion Coefficient Research Articles

Regularities of liquid potassium at different temperatures

Several new regularities in liquid potassium have been found from the existing experimental data and calculated thermodynamic properties along the isothermal lines with the equation of state (EoS) of a power law form. The quantity (Z − 1)V2 is linearly proportional to V2 with a common intersection point for all isotherms at high temperature and PintV versus V−2 is nearly linear, where Z, V and Pint are compressibility factor, molar volume and internal pressure. Both the isothermal bulk modulus and internal pressure are nearly a linear function of pressure at constant temperature. There is a linear relationship existing between the calculated reduced isothermal bulk modulus and V−2. Based on the linear isotherm regularity EoS, analytical expression of thermodynamic properties of liquid potassium can be obtained. Furthermore, we found crossing points existing in the isobaric thermal expansion coefficient and Anderson-Grüneisen parameter.

Numerical solutions of compressible convection with an infinite Prandtl number: comparison of the anelastic and anelastic liquid models with the exact equations

We developed a numerical method for the set of equations governing fully compressible convection in the limit of infinite Prandtl numbers. Reduced models have also been analysed, such as the anelastic approximation and the anelastic liquid approximation. The tests of our numerical schemes against self-consistent criteria have shown that our numerical simulations are consistent from the point of view of energy dissipation, heat transfer and entropy budget. The equation of state of an ideal gas has been considered in this work. Specific effects arising because of the compressibility of the fluid are studied, like the scaling of viscous dissipation and the scaling of the heat flux contribution due to the mechanical power exerted by viscous forces. We analysed the solutions obtained with each model (fully compressible model, anelastic and anelastic liquid approximations) in a wide range of dimensionless parameters and determined the errors induced by each approximation with respect to the fully compressible solutions. Based on a rationale on the development of the thermal boundary layers, we can explain reasonably well the differences between the fully compressible and anelastic models, in terms of both the heat transfer and viscous dissipation dependence on compressibility. This could be mostly an effect of density variations on thermal diffusivity. Based on the different forms of entropy balance between exact and anelastic models, we find that a necessary condition for convergence of the anelastic results to the exact solutions is that the product $\unicode[STIX]{x1D716}q$ must be small compared to unity, where $\unicode[STIX]{x1D716}$ is the ratio of the superadiabatic temperature difference to the adiabatic difference, and $q$ is the ratio of the superadiabatic heat flux to the heat flux conducted along the adiabat. The same condition seems also to be associated with a convergence of the computed heat fluxes. Concerning the anelastic liquid approximation, we confirm previous estimates by Anufriev et al. (Phys. Earth Planet. Inter., vol. 152, 2005, pp. 163–190) and find that its results become generally close to those of the fully compressible model when $\unicode[STIX]{x1D6FC}T{\mathcal{D}}$ is small compared to unity, where $\unicode[STIX]{x1D6FC}$ is the isobaric thermal expansion coefficient, $T$ is the temperature (here $\unicode[STIX]{x1D6FC}T=1$ for an ideal gas) and ${\mathcal{D}}$ is the dissipation number.

Anomalous and Not-So-Common Behavior in Common Ionic Liquids and Ionic Liquid-Containing Systems.

This work highlights unexpected, not so well known responses of ionic liquids and ionic liquid-containing systems, which are reported in a collective manner, as a short review. Examples include: (i) Minima in the temperature dependence of the isobaric thermal expansion coefficient of some ILs; (ii) Viscosity Minima in binary mixtures of IL + Molecular solvents; (iii) Anomalies in the surface tension within a family of ILs; (iv) The constancy among IL substitution of Cp/Vm at and around room temperature; (v) ILs as glass forming liquids; (vi) Alternate odd-even side alkyl chain length effects; (vii) Absolute negative pressures in ILs and IL-containing systems; (viii) Reversed-charged ionic liquid pairs; (ix) LCST immiscibility behavior in IL + solvent systems.

Molecular interactions between some amino acids and a pharmaceutically active ionic liquid domiphen DL-mandelic acid in aqueous medium at temperatures from 293.15 K to 313.15 K

Molecular interactions between some amino acids (glycine, l-alanine, l-valine and l-leucine) and a pharmaceutically active ionic liquid domiphen DL-mandelic acid ([DOM][MAN]) in aqueous solution at various temperatures have been studied by means of volumetric, conductivity and spectroscopy measurements. Density data were used to derive standard partial molar volume, V2,φ0 standard partial molar expansibility, Eφ0, standard transfer volume, ΔtV0, isobaric thermal expansion coefficient, α0 and hydration number, nH of amino acids. On the basis of the experimental conductivity and fluorescence spectroscopy data, the aggregation behaviour of [DOM][MAN] in aqueous amino acid solutions was investigated. Critical micelle concentration, cmc, aggregation number, Nagg, some thermodynamic functions, ΔGm0, ΔHm0, ΔSm0 and ΔCp0 of micellization for [DOM][MAN] have been obtained. Effect of concentration and temperature on the obtained parameters has been discussed. Binding constant Kb for amino acid-[DOM][MAN] complex estimated using the UV–vis spectroscopic data approved that the solute-solvent interactions were strengthened by elevating the size of alkyl part of amino acids.

An experimental investigation of molecular interactions between [Emim][triflate] ionic liquid & 2-alkoxyethanols and theoretical comparison by PFP theory

Physical properties, such as density (ρ) and speed of sound (u) of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 2-ethoxyethanol/2-propoxyethanol and their binary mixtures are measured over the whole composition range as a function of temperature between 298.15 K and 318.15 K at atmospheric pressure. Experimental values were used to calculate the excess molar volumes (VmE), excess values of partial molar volumes (V¯mE), excess values of isentropic compressibility (κsE), free length (LfE), speeds of sound (uE) and isobaric thermal expansion coefficient (αPE) for the binary mixtures. These excess properties were fitted to the Redlich-Kister type equation to obtain the binary coefficients and the standard deviations. A qualitative analysis of these parameters indicates the interaction decreases with the increase in chain length. This was further supported by Prigogine–Flory–Patterson (PFP) theory of excess molar volume.

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.

Thermodynamic and solution properties of sodium valporate in aqueous solution and its interaction with cetyl trimethylammonium bromide (CTAB)

This manuscript reports the volumetric, viscometric and aggregation properties of sodium valporate in aqueous solution. The interaction of drug with cationic surfactant (CTAB) was also studied. From volumetric study, partial molar volume, Hepler's constant, partial molar expansivity and isobaric thermal expansion coefficient were calculated while from viscometric study, the constants of Jones-Dole equation and thermodynamic parameters of viscous flow like free energy change, entropy change and enthalpy change were calculated. Critical micelle concentration of drug at four different temperatures was measured by surface tension and electrical conductivity measurements. The data was used to calculate surface excess concentration and thermodynamic parameters for the micellization process i.e. free energy of adsorption, free energy, entropy and enthalpy of micellization. Spectroscopic study of the drug/surfactant interaction was helpful to calculate partition coefficient, free energy of partition, binding constant and free energy of binding.

Thermodynamic Relations among Isotropic Material Properties in Conditions of Plane Shear Stress.

We present new general relationships among the material properties of an isotropic material kept in homogeneous stress conditions with hydrostatic pressure and plane shear. The derivation is not limited to the proximity of the zero shear-stress and -strain condition, which allows us to identify the relationship between adiabatic and isothermal shear compliances (inverse of the moduli of rigidity) along with new links, among others, between isobaric and isochoric shear thermal expansion coefficients and heat capacities at constant stress and constant shear strain. Such relationships are important for a variety of applications, including the determination of constitutive equations, the characterization of nanomaterials, and the identification of properties related to earthquakes precursors and complex media (e.g., soil) behavior. The results may be useful to investigate the behavior of materials during phase transitions involving shear or in non-homogeneous conditions within a local thermodynamic equilibrium framework.

Thermophysical Study of Binary Systems of tert-Amyl Methyl Ether with n-Hexane and m-Xylene

This work presents the experimentally determined density (ρ), viscosity (η), speed of sound (u), and surface tension (σ) data for tert-amyl methyl ether (TAME) + n-hexane and TAME + m-xylene systems at several temperatures (298.15, 308.15, 318.15, 323.15, and 328.15 K). These experimentally determined thermophysical data are utilized to compute various excess/deviation parameters such as molar volume (VE), isentropic compressibility (κsE), speed of sound (uE), deviation in viscosity (Δ ln η), isobaric thermal expansion coefficient (αPE), and surface tension (σE). The inspection of parameters response may interpret the existing specific molecular interactions as well as the mixing behavior of solutions. The critical analysis of observed parametric behavior have unveiled the strong and weak molecular interactions in TAME with m-xylene and TAME with n-hexane systems, respectively.

Investigation of thermophysical properties for aqueous blends of sarcosine with 1-(2-aminoethyl) piperazine and diethylenetriamine as solvents for CO2 absorption

The present study reports the thermophysical properties such as density and viscosity for aqueous blends of sarcosine (SAR) with 1-(2-aminoethyl) piperazine (APZ) and diethylenetriamine (DETA). The properties have been measured for various mass fractions at atmospheric pressure and temperature ranging from 298.15 to 333.15 K. The analysis of physical property data revealed that both density and viscosity increased with an increase in the mass fraction for both SAR-APZ and SAR-DETA aqueous blends. While these properties showed an opposite behavior with the rise in temperature for both the studied aqueous blends. The experimental density data were used to estimate the isobaric thermal expansion coefficient. A marginal increase and decrease were observed in the estimated isobaric thermal expansion coefficient with an increase in temperature and mass concentration respectively, for both aqueous systems. In addition, empirical correlations such as modified Graber equation and Vogel-Tamman-Fulcher equations were used to correlate the experimental density and viscosity data as a function of temperature and concentration. The correlations were found reliable for the data interpolation.

Volumetric and Optical Properties of Dimethylvinylethoxysilane with n-Alkanes (C7 to C10) at Temperatures in the Range (298.15 to 318.15) K

Densities and refractive indices are investigated for four binary mixture systems of dimethylvinylethoxysilane with n-heptane, n-octane, n-nonane and n-decane at different temperatures (298.15, 303.15, 308.15, 313.15 and 318.15 K) and atmospheric pressure. From these experimental data, the excess molar volume, isobaric coefficient of thermal expansion, deviation in refractive index, molar refraction, and deviation in the molar refraction have been calculated. The computed quantities have been fitted with the Redlich–Kister equation to derive the coefficients and estimate the standard deviations. The values of the partial excess volume at infinite dilution were calculated using the coefficients of the Redlich–Kister smoothing equation. The effects of composition and temperature on these properties are discussed.

Preparation and characterization of amine (N-methyl diethanolamine)-based transition temperature mixtures (deep eutectic analogues solvents)

In this study, three mixtures of methylyltriphenylphosphonium bromide (MTPPB) as hydrogen bond acceptor (HBA) and N-methyl diethanolamine (MDEA) as hydrogen bond donor (HBD) component was used to prepare transition temperature mixtures (TTMs) into different mole ratios of 1:7, 1:10 and 1:16 HBA/HBD. Two important physicochemical properties of TTMs such as density and refractive index were investigated at the atmospheric pressure and temperature ranges of (293.15–353.15) K and (293.15–343.15) K, respectively. The experimental density data were used to derive the molar volume, molecular volume, lattice energy and isobaric thermal expansion coefficients. With the help of experimental refractive index data, the electronic polarization, molar refraction, and free volume were calculated at the whole temperatures. Several empirical equations were used to correlate refractive indices such as an empirical equation and one-parameter equations (Dale–Gladstone, Eykman, Lorentz–Lorenz, Newton, Arago–Biot, and Oster). Finally, the response surface methodology (RSM) was applied to evaluate the effects of two main factors such as temperature and mole ratio on the density and refractive index of TTMs. The results revealed that the molar ratio has almost a higher effect on the studied properties than temperature.

Physicochemical and thermodynamic properties of the {1-alkyl-1-methylpiperidinium bromide [C1Cn=2,4PIP][Br], or 1-butylpyridinium bromide, [C4Py][Br], or tri(ethyl)butylammonium bromide [N2,2,2,4] [Br] + water} binary systems

This work is a continuation of our comprehensive study of ionic liquids, ILs (including organic salts with melting temperature above 100 °C) and their aqueous solutions as a novel alternative working pair for the absorption heat pump. A series of organic salts: 1-ethyl-1-methyl-piperidinium bromide, [C1C2PIP][Br], 1-butyl-1-methyl-piperidinium bromide, [C1C4PIP][Br], 1-butylpyridinium bromide, [C4Py][Br] and tri(ethyl)butylammonium bromide, [N2,2,2,4][Br] have been synthesized. The structures of compounds have been confirmed using NMR spectra. The basic thermal characterization of pure organic salts, including temperature and enthalpy of phase transition (Ttr, ΔtrH), temperature and enthalpy of melting (Tfus, ΔfusH) have been measured using a differential scanning microcalorimetry technique (DSC). The physico-chemical properties that are: density (ρ) and dynamic viscosity (η) of the tested binary systems have been determined at wide temperature and composition range. From experimental densities data, the apparent molar volumes (Vϕ,1) were calculated. In order to obtain limiting apparent molar volumes (Vϕ,10), the concentration dependence of apparent molar volumes was correlated with Redlich–Mayer type equation. Additionally, the limiting molar expansibilities (Eϕ0) and isobaric thermal expansion coefficients (αP) have been calculated. Temperature dependence of the dynamic viscosity has been correlated using VFT equation. The solid−liquid phase equilibria (SLE) have been determined using a dynamic method and correlated using NRTL equation. The influence of the alkyl chain length in the piperidinium cation substituent, as well as the cation structure, on investigated properties are presented and discussed.

High Pressure Volumetric Properties and Viscosity of Base Oils Used in Automotive Lubricants and Their Modeling

Temperature and pressure effects on density and viscosity are reported for six base oils consisting of four mineral oils and two synthetic oils composed of poly(α-olefins). Using a variable-volume view cell, density data were collected at 298, 323, 348, 373, and 398 K from 10 to 40 MPa. The data were then fit to the Sanchez–Lacombe equation of state and used to determine isothermal compressibility, isobaric thermal expansion coefficient, and internal pressure. Compressibility and internal pressure were found to vary based on composition, specifically with cycloalkane content. Viscosity data were collected as a function of temperature, pressure, and rotational speed using a custom-built high pressure rotational viscometer. Data were collected at 298, 323, 348, and 373 K from 10 to 40 MPa at rotational speeds of 300–800 rpm. A free-volume model was used to model the viscosity and relate the viscous effects to density.

Densities, Apparent Molar Volume, Expansivities, Hepler’s Constant, and Isobaric Thermal Expansion Coefficients of the Binary Mixtures of Piperazine with Water, Methanol, and Acetone at T = 293.15 to 328.15 K

The properties of 3 binary mixtures containing piperazine were investigated in this work. In a first step, the densities for the two binary mixtures (piperazine + methanol) and (piperazine + acetone) were measured in the temperature range of 293.15 to 328.15 K and 293.15 to 323.15 K, respectively, at atmospheric pressure by using a Rudolph research analytical density meter (DDM 2911). The concentration of piperazine in the (piperazine + methanol) mixture was varied from 0.6978 to 14.007 mol/kg, and the concentration of piperazine in the (piperazine + acetone) mixture was varied from 0.3478 to 1.8834 mol/kg. On the other hand, the density data for the (piperazine + water) mixture were taken from the literature in the temperature range of 298.15 to 328.15 K. In a second step, for the 3 investigated systems, the apparent molar volume (Vϕ) and the limiting apparent molar volume (Vϕ0) at infinite dilution were calculated using the Redlich–Mayer equation. The limiting apparent molar volumes (Vϕ0) were used to study the influence of the solute-solvent and solute-solute interactions. The temperature dependency of the apparent molar volumes was used to estimate the apparent molar expansibility, Hepler’s constant ∂2Vϕ0/∂T2P, and isobaric thermal expansion coefficients αP.

Thermo physical, optical and spectroscopic perspectives of molecular interactions in binary mixtures of Ethyl Lactate and Dimethyl Adipate at T = 303.15–318.15 K and atmospheric pressure

ABSTRACTMolecular interactions are evaluated in the binaries of Ethyl Lactate and Dimethyl Adipate using experimental values of density, ultrasonic velocity and refractive index over entire composition range as a function of temperature from 303.15 to 318.15 K at atmospheric pressure. Excess thermodynamic properties: excess molar volume, excess isentropic compressibility, excess isothermal compressibility, excess free length, excess isobaric thermal expansion coefficient, excess ultrasonic velocity and refractive index deviations are computed and fitted with Redlich-Kister polynomial equation to obtain the binary coefficients and the standard deviations. The existence of specific interactions in the mixture is revealed by excess properties, and further supported by partial molar properties. FTIR analysis ascertains the dominance of packing effect in the studied mixtures. Prediction of refractive index for the mixtures and pure components is done by several mixing rules with the estimation of relative errors. In addition, data are analysed by the Prigogine–Flory–Patterson theoretical model.

Molecular interaction studies of binary mixture formed by 2-methoxyethanol and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide-based ionic liquid

ABSTRACTPhysicochemical properties such as density (ρ), speed of sound (u) and refractive index (nD) for binary mixture of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with 2-methoxyethanol (2-ME), have been investigated over the whole composition range at different temperatures (298.15–318.15) K and ambient pressure. Additionally the excess properties such as excess molar volume (), excess molar isentropic compressibility (), excess isobaric thermal expansion coefficient (), deviation in refractive index () and partial molar quantities, have been also evaluated, simultaneously these are fitted with Redlich-Kister type equation for acquiring the binary coefficients and standard deviations. The calculated data has been interpreted in terms of various interactions and structural property between organic and ionic liquid molecules upon mixing. ATR-FTIR studies also carried out to know the microscopic interactions. The experimentally obtained excess molar volumes are further analysed with the help of Prigogine-Flory-Patterson (PFP) theory.

Temperature and concentration dependence towards physicochemical and FTIR spectral studies of glycine, L-alanine and L-valine in aqueous solutions of nortriptyline hydrochloride

Apparent and partial molar properties for glycine, L-alanine and L-valine in aqueous solutions (0.025–0.075) mol·kg−1 of drug NTPH (nortriptyline hydrochloride) have been reported in the present study at intervals of 5 K from temperature 288.15 K to 308.15 K and at experimental pressure of p=0.1 MPa. Different parameters viz. transfer partial molar properties, hydration numbers (nH), partial molar expansibility (E∅0), isobaric thermal expansion coefficient (α) and Hepler’s constant, calculated by using the experimental data of density (ρ) and ultrasonic speeds (u) predict that the solute-solvent interactions are dominating in these ternary systems. The linear variation of V∅0 with the number of carbon atoms in the alkyl chain of amino acids has been utilized to calculate the contribution of the charged end groups NH3+,COO-, (CH2) group and other alkyl chains of the amino acids to V∅0. Pair and triplet interaction coefficients determined from ΔV∅0 and ΔK∅,s0 values using McMillan-Mayer theory indicate the dominance of pairwise interactions in the studied ternary mixtures. The hydration number (nH) comes out to be positive suggesting strong dehydration effect of NTPH. FTIR spectra have been recorded for the mixtures of amino acids in aqueous solutions of NTPH. The decrease in wave number of N–H stretching band also suggests the structural changes in these systems.

BARIC DEPENDENCE OF LATTICE PROPERTIES FOR DIAMOND

Based on the pairwise interatomic potential of Mi-Lennard-Jones and the Einstein's model of crystal the state equation P(V/V0, T) and the baric dependencies of the lattice properties for diamond were obtained. The calculations were performed along two isotherms: T = 300 and 3000 K and until to P = 10000 kbar (i.e. until to the relative volume V/V0 = 0.5). The baric dependencies for the following properties were obtained: isothermal elastic modulus, isochoric and isobaric heat capacities and thermal expansion coefficient. Good agreement with experimental data was obtained.

A new insight into pure and water-saturated quaternary phosphonium-based carboxylate ionic liquids: Density, heat capacity, ionic conductivity, thermogravimetric analysis, thermal conductivity and viscosity

Abstract Ionic Liquids (ILs) are task specific materials with tunable properties which may be applied as heat transfer fluids (HTFs) due to their characteristic properties including low vapour pressure, wide liquid range and high thermal stability. This study provides an evaluation of their potential as HTFs from both their physicochemical properties as well as an economic comparison with commonly used materials. The paper presents the thermophysical properties (density, isobaric heat capacity, ionic conductivity, viscosity, thermal stability by TGA, thermal conductivity) and their thermodynamic derivatives (isobaric thermal expansion coefficient, excess molar volume, excess molar heat capacity), as well as the Walden rule of ionicity for a range of hydrophobic ILs based on the trihexyl(tetradecyl)phosphonium, ([P14,6,6,6]+), cation. The ionic liquids studied are trihexyl(tetradecyl)phosphonium acetate ([AcO]−), butanoate ([ButO]−), hexanoate ([HexO]−), octanoate ([OctO]−), and decanoate ([DecO]−), as well as their mixtures with water. It was shown that investigated systems are highly promising materials as HTFs, especially ILs + water mixtures, which may be the solution for many engineering issues.