Molar Isobaric Thermal Expansion Research Articles

Thermodynamic properties of {glycerol (1) + tert-butanol (2)} mixtures at temperatures from 278 K to 323 K and pressures up to 100 MPa

In the present study the densities at atmospheric pressure and the compression coefficients of a binary liquid mixture {glycerol (1) + tert-butanol (2)} were measured within the temperature range from 278.15 K to 323.15 K (278.15, 288.15, 288.15, 308.15 and 323.15) and pressures up to 100 MPa (10, 25, 50, 75 and 100). Due to the limited solubility of tert-butanol in glycerol and the transition of the mixture to the solid phase the measurements at 278.15 K and 100 MPa were carried out up tox2 = 0.45 (x2 is the mole fraction of tert–butanol). The excess molar volumes, molar isothermal compression, molar isobaric thermal expansion, isochoric coefficient of thermal pressure mixtures, as well as the partial molar volumes of the mixture components, including their limit values, were calculated. The excess molar volume values at 323.15 K (the only temperature at which the compression was measured over the entire composition range) were found to be negative. The partial molar volume of glycerol (GL) at 323.15 K was characterized by the presence of a baric inversion region. The limiting partial molar volume of GL was shown to decrease in its own environment as the pressure rose and to increase in the TBA environment. The molar isothermal compression of the mixture varied depending on the composition without extremes, and the partial molar isothermal compression of GL had negative values. The molar isobaric thermal expansion of the mixture in the area of small tert-butanol (TBA) additives changed slightly at low temperatures and pressures and the increase in both the pressure and the temperature led to dispersion of their concentration dependences. The isochoric coefficient of thermal pressure decreased with an increase in x2, forming a small plateau at small TBA additions. The results obtained were discussed from the perspective of solute–solvent and solute–solute interactions.

Density, viscosity, refractive index and molecular interaction of polyethylene glycol 400 + 1,3-propanediamine deep eutectic solvent for CO2 capture

A new deep eutectic solvent (DES) was obtained using polyethylene glycol 400 (PEG400) as the H bond donor (HBD) and 1,3-propanediamine (PDA) as the H bond acceptor (HBA). Meanwhile, density(ρ), viscosity (η) and refractive index (nD) of (PEG400 + PDA) DES at T = (293.15 to 318.15) K with the step size of 5 K were measured under atmospheric pressure. Through the measured base data, excess molar volume (VmE), excess refractive index (nDE), viscosity deviation (Δη), deviation in molar refraction (ΔRM), refractive index deviation(ΔnD), excess Gibbs energy of activation of viscous flow (ΔG∗E), partial molar volume (V1¯ and V2¯), apparent molar volume (Vφ,1 and Vφ,2), molar isobaric thermal expansion (Ep,m) and thermal expansion coefficient (αρ), were systematically calculated and analyzed, and the Redlich-Kister (R-K) equation was used for fitting VmE, nDE, ΔRM, Δη, ΔnD, and ΔG∗E. In addition, several theoretical mixing rules related to refractive index were evaluated and compared with the experimental data. The results showed that there was a specific intermolecular hydrogen bonding interaction in (PEG400 + PDA) DES, which was systemically discussed on the basis of UV–vis, FLS, FTIR and Raman spectral technologies. At the molar fraction with the strongest intermolecular force, the maximum solubility of CO2 per 1 mol PDA was 0.99 mol CO2 at 150 mL/min CO2 flow rate.

Density, viscosity, surface tension, and spectral analysis of polyethylene glycol 300 + 1,2-Propylenediaminebinary liquid mixture

At T = 293.15 ∼ 318.15 K, the density (ρ), viscosity (η), and surface tension (γ) data of polyethylene glycol 300 (PEG300) and 1,2-propane diamine (1,2-PDA) binary liquid mixture in the entire composition range were systemically measured. Meanwhile, the influence of different temperatures on the physical properties of the binary liquid mixture was deeply discussed. The values of ρ and η of PEG300 were compared with the reported values of ρ and η of different linear alcohols under the same experimental conditions. It was found that the values of ρ and η of linear alcohols were related to the number of carbon chains. Under isothermal conditions, the values of ρ and η increased with the number of carbon chains. After that, excess molar volume (VmE), excess viscosity (ηE), surface tension deviation (Δγ), excess Gibbs energy of activation of viscous flow (ΔG∗E), and molar isobaric thermal expansion (Ep,m) of PEG (1) + 1,2-PDA (2) binary mixture were calculated. The η values were fitted with four semi-empirical formulas, and the VmE, ηE, and Δγ values were fitted with Redlich-Kister (R-K) equation. IR, UV, FLS, and Raman spectral technologies were used to further prove the interaction among different molecules of the liquid mixture.

Liquid phase PVTx properties of {water (1) + 1,3-dimethylurea (2)} mixtures at temperatures from 278.15 to 323.15 K and pressures to 100 MPa

In this study, the compression coefficients k=ΔV/Vo of the binary mixture {water (1) + 1,3-dimethylurea (2)} were measured within the temperature range from 278.15 K to 323.15 K (278.15, 288.15, 288.15, 308.15, 323.15), the pressure range from 10 to 100 MPa (10, 25, 50, 75 and 100) and the composition range up to x2 = 0.19364 (1,3-dimethylurea mole fraction). The molar isothermal compression, KT,m, molar isobaric thermal expansion, EP,m, isochoric coefficient of thermal pressure, βV, and the internal pressure of the mixture, Pint, were calculated. It was demonstrated that the concentration dependences (on the mole fraction of 1,3-dimethylurea (1,3-DMU)) of the molar isothermal compressions of the mixture at low pressures and low temperatures are characterized by a minimum at x2≈0.06 ÷ 0.07, which levels out both with increase in pressure and with increase in temperature. The molar isobaric thermal expansion of the mixture increases with an increase in the 1,3-DMU concentration for all state parameters. At low temperatures, the concentration dependences of the molar expansion are characterized by the presence of a pressure inversion zone. The concentration dependences of the isochoric coefficient of thermal pressure of the mixture indicate the hydrophobic properties of the 1,3-DMU molecule become stronger at high pressures. The obtained results are discussed in terms of solute–solvent and solute–solute interactions.

The density, viscosity, speed of sound, excess properties of binary mixtures of linear polydimethylsiloxane and various alkanes at temperatures in the range (288.15–328.15) K

This article describes the binary system composed of linear polydimethylsiloxane (PDMS) and diesel fuel main components n-decane, n-dodecane, n-tridecane and n-tetradecane at atmospheric pressure, and the density, viscosity and speed of sound were measured at 288.15 K, 298.15 K, 308.15 K, 318.15 K and 328.15 K, respectively. Their excess molar volume (VmE), excess viscosity (ηE), excess molar Gibbs free energy (ΔGEm), molar isobaric thermal expansion (EP,m) and excess molar isentropic compressibility (κEs,m) were calculated. The influence of the intermolecular force, steric hindrance, molecular stacking and other factors on the excessive properties of the binary system solution was discussed. The results indicate that with an increase in carbon chain length, the excess molar volume, excess viscosity, molar isobaric thermal expansion and excess molar isentropic compressibility increased and excess molar Gibbs free energy decreased, which probably ascribe to the increase in steric effect and the stronger interactions between homo-molecular than those of hetero-molecular interactions between PDMS and long-chain alkane molecules.

Volumetric properties (water + 1,3-dimethylurea) mixture over the temperature range from 274.15 to 333.15 K at the ambient pressure – comparison with other methyl substituted analogues

Measurements of the binary mixture {water (1) + 1,3-dimethylurea (2)} density within the temperature range of 274.15 to 333.15 K were performed within a wide range of compositions at the atmospheric pressure by using the density gauge with a U-shaped vibrating tube. There are calculated apparent and partial molar volumes of water and 1,3-dimethylurea (1,3-DMU) in the mixture, limiting (standard) partial molar volumes of 1,3-DMU in water, molar isobaric thermal expansion of the mixture and molar isobaric thermal expansion of 1,3-DMU at infinite dilution. It is shown that concentration dependences of partial molar volumes of the water and 1,3-DMU are characterized by the presence of extremums thus revealing manifestation of hydrophobic nature of the 1,3-dimethylurea molecule. Limiting partial molar volumes of 1,3-DMU increase with the increase of the temperature. Increasing both the temperature and the concentration of 1,3-DMU lids to the increasing of the molar isobaric expansion of the mixture. The obtained results are discussed in terms of the solute – solvent and solute – solute interactions. A comparison of the obtained characteristics with similar characteristics of the urea, N-methylurea and tetramethylurea is performed.

Densities and thermal expansions of (water + tetrahydrofuran) mixtures within the temperature range from (274.15 to 333.15) K at atmospheric pressure

The mixture {water (1) + tetrahydrofuran (2)} densities have been measured over the whole composition range at temperatures between (274.15 and 333.15 K) and atmospheric pressure using the vibration type densimeter. Values of excess molar volume and molar isobaric thermal expansion of the mixture as well as apparent/partial molar volumes (down at infinite dilution) for water and tetrahydrofuran (THF) have been calculated. It is shown that the formation of the water + THF mixture occurs with decreasing its volume under all the temperatures. Concentration dependences of partial molar volumes of water and THF are characterized by the presence of extreme regions. Standard (limiting) partial molar volumes of water and THF increase as the temperature is rising. Increase in both temperature and THF content influence on the value of molar isobaric expansion of the mixture in the same way.

The (p-Vm-T-x) properties of {water (1) + acetamide (2)} mixtures in the range 278.15–323.15 K and 0.10–100 MPa

The density ρ at atmospheric pressure and compression ratios k=ΔV/Vo of the {water (1) + acetamide (2)} mixture in the range of temperature from 278.15 K to 323.15 K (278.15, 288.15, 298.15, 308.15, 323.15), pressures from 10 to 100 MPa (10, 25, 50, 75 and 100) and in a wide range of compositions (maximum mole fraction of acetamide (AA) x2 = 0.3875) were measured in the work. The partial molar volumes of both components V¯1 and V¯2 in the mixture, molar isothermal compression KT,m, molar isobaric thermal expansion EP,m, isochoric coefficient of thermal pressure βV, and internal pressure of the mixture Pint were calculated. The volume characteristics for an infinitely dilute AA solution in water: limiting partial molar volumes V¯2∞, limiting partial molar isothermal compression K¯T,2∞, and limiting partial molar isobar expansion E¯P,2∞ were calculated. The obtained results are discussed from the standpoint of interactions of solute-solvent and solute-solute. The obtained results are discussed in terms of solute-solvent and solute-solute interactions.

Volumetric properties of the water + tetramethylurea mixture over the temperature range from 274.15 to 333.15 K at atmospheric pressure

The densities of the binary mixture {water (1) + tetramethylurea (2)} have been measured in the entire composition range in the temperature range from 274.15 K to 333.15 K at atmosphere pressure. Excess molar volumes and molar isobaric thermal expansions of the mixture, apparent and partial molar volumes, partial molar isobaric expansions of water and tetramethylurea (TMU), including their limiting values, are calculated. It is shown that the formation of the water + tetramethylurea mixture occurs with a decrease in the volume of the mixture at all temperatures, and the partial molar volumes of water and TMU increase with increasing temperature. The temperature dependences of the limiting partial molar isobaric thermal expansions of both components are characterized by the presence of the extremum. The obtained results are discussed in terms of solute-solvent and solute-solute interactions.

Effect of high pressure and temperature on the volume properties of the liquid-phase mixture of {water (1) + formamide (2)}

Compression, k = Δv/vo, was measured for the {water (1) + formamide (2)} binary mixture within the whole range of the component ratio at temperatures from 278.15 K to 323.15 K and pressure up to 100 MPa. Molar isothermal compressions, molar isobaric thermal expansions, isochoric coefficient of thermal pressure and internal pressure were calculated. Concentration dependences (from formamide content) of molar isothermal compressions for water + formamide mixtures at low pressure and temperature (close to 278.15 K) were featured with the minimum at x2 ≈ 0.1, which was smoothed over with both pressure and temperature increase. Molar isobaric thermal expansions of the mixture increased with the increase of formamide content in it at all state parameters; pressure increase resulted in temperature inversion in its concentration dependence, which shifted to the area of lower formamide (FA) concentration with the pressure increase. Isochoric coefficient of thermal pressure of the mixture drastically increased in the area of small FA additions. The temperature effect on the thermal pressure coefficient was opposite in the mixtures with high water and high formamide content. Calculated values for pure components were also compared.

Density and volumetric properties of the aqueous solutions of urea at temperatures from T = (278 to 333) K and pressures up to 100 MPa

Abstract This paper highlights the values of densities of aqueous solutions of urea in the concentration range m (from 0.1809 to 12.801) mol·kg−1 at T = (278.15, 288.15, 298.15, 308.15, 323.15 and 333.15) K and at p = (0.101, 10, 25, 50, 75 and 100) MPa. The densities were also measured for dilute aqueous solutions m (from 0.093 to 2.505) mol·kg−1 with temperature from 274.15 to 283.15 K, with increment of 1 K at atmospheric pressure, in order to study the effect of urea on the temperature of the maximum water density. Volumetric properties calculated from the density, such as apparent molar volumes of urea, Vɸ,2, molar isothermal compressions, KT,m, and molar isobaric thermal expansions, EP,m, of solution are considered depending on concentration, temperature and pressure. Also, certain volumetric characteristics for infinitely diluted urea in water were obtained: the limiting partial molar volumes, V 2 ∞ ; limiting partial molar isothermal compressions, K T , 2 ∞ ; and limiting partial molar isobaric thermal expansions, E P , 2 ∞ . Obtained results are discussed from the standpoint of solute – solute and solute – solvent interactions. With the help of various approaches based on volumetric characteristics, the character of the disturbing effect of urea on the water structure was described.

Densities and Volumetric Properties of Aqueous Solutions of {Water (1) + N-Methylurea (2)} Mixtures at Temperatures of 274.15–333.15 K and at Pressures up to 100 MPa

Densities of the mixture {water (1) + N- methylurea (2)} in the concentration range to mole fraction x2 = 0.07071 (or to the solution molality concentration m2 = 4.22335 mol·kg–1) at atmospheric pressure in the temperature range from 274.15 to 333.15 K and compression k = ΔV/V0 at pressures to 100 MPa (10, 25, 50, 75, and 100) in the temperature range from 278.15 to 323.15 K (278.15, 288.15, 288.15, 308.15, 323.15) in the same concentration range were calculated in this study. The apparent molar volumes of N-methylurea Vϕ,2 and the partial molar volumes of both components V̅1 and V̅2 in the mixture, molar isothermal compressibilities KT,m, molar isobaric thermal expansions EP,m, and isochoric coefficients of thermal pressure β of the mixture were calculated. Moreover, volumetric measures for the infinitely dilute solution of N-methylurea solution were calculated: limiting partial molar volumes V̅2∞, the limiting partial molar isothermal compressibilities K̅T,2∞, and the limiting partial molar isobaric thermal expansions E̅P,2∞. The results obtained are discussed from the point of view of solute–solvent and solute–solute interactions.

Densities and Molar Isobaric Thermal Expansions of the Water + Formamide Mixture over the Temperature Range from 274.15 to 333.15 K at Atmospheric Pressure

The density of the {water (1) + formamide (2)} mixture has been measured over the whole composition range at temperatures from 274.15 to 333.15 K at atmospheric pressure using the vibration densimeter. The volumetric parameters of the mixture, such as the excess molar volume, molar isobaric thermal expansions, and apparent and partial molar volumes of water and formamide, as well as their limiting values, have been calculated. It was shown that the mixture formation resulted in the volume decrease at all temperatures, and the largest absolute value of the excess molar volume corresponded to the mixture composition of 2H2O-FA. The limiting partial molar volumes of water and formamide increased with the temperature rise. At a temperature of about 323 K the limiting partial molar volume of water became larger than its own molar volume.

Excess Volume of the 1-Propanol + 1-Alkene Systems in Terms of an Equation of State with Association

The measurements of excess molar volume VE at 298.15 K for binary mixtures formed by 1-propanol with 1-alkene (C6, C7) and excess molar volume VE at (288.15, 298.15, and 308.15) K with 1-decene are reported. For the 1-decene system, the excess molar isobaric thermal expansion APE at 298.15 K is estimated. These data together with VE and APE at 298.15 K for 1-propanol with 1-octene published previously (Treszczanowicz et al. J. Solution Chem. 2002, 31, 455−466 and 2004, 33, 275−285) are discussed and interpreted in terms of the Treszczanowicz and Benson (TB) model adapted for mixtures of self-associated component and active solvent. The model contains the Flory equation of state (EOS) combined with the association model proposed by Treszczanowicz and Kehiaian. The Flory EOS interaction interchange parameter is described in terms of the Kehiaian group contribution method taking into account the OH···π interactions and nonspecific interactions. The model predicts qualitatively well the shape of the VE and th...

Temperature dependence of the excess molar volume of 1-hexanol + 1-alkene systems in terms of an association and equation of state model

Excess molar volumes V E measured at 288.15 and 308.15 K for (1-hexanol + 1-hexene), (1-hexanol + 1-octene) and (1-hexanol + 1-decene) systems are reported. The data and the measurements reported before at 298.15 K for this series of mixtures were used to estimate the excess molar isobaric thermal expansion A p E = ( ∂ V E / ∂ T ) p and the partial molar excess isobaric thermal expansions A p , i E of the components at 298.15 K. The A p E as a function of concentration, changes from positive–negative for the systems formed by short-chain 1-alkenes like 1-hexene to positive for 1-decene over the whole concentration range. The modified Treszczanowicz and Benson model (TB) is applied to interpret and to predict changes in the size and shape of the A p E and A p , i E curves. The model predicts qualitatively well the changes of the A p E and A p , i E values in the series of mixtures as a superposition of the contributions due to self-association of alkanol, free volume, OH⋯π interactions and residual van der Waals interactions. These contributions to the properties investigated are estimated and discussed in the series of mixtures. The results obtained are compared with those for 1-alkanol + n-alkane systems.

Prediction of temperature dependence of the excess volume: (∂ VE/∂ T) p and (∂ 2VE/∂ T2) p for 1-alkanol + an alkane binary systems in terms of an associated mixture model

The predictive ability of the model proposed by Treszczanowicz and Benson [Fluid Phase Equilib. 23 (1985) 117] is tested for temperature dependence of the excess volume: excess molar isobaric thermal expansion defined as A p E=( ∂V E/ ∂T) p and ( ∂ 2 V E/ ∂T 2) p for binary systems formed by an 1-alkanol (from C 2 to C 12) and an alkane (from C 4 to C 14) for all available literature data. The model equations for these properties are expressed as sums of the three contributions: self-association described by athermal associated mixture model and free volume and non-specific interactions described by Flory equation of state. The model correctly predicts A p E and sign of temperature derivative ( ∂ 2 V E/ ∂T 2) p for regarded class of mixtures. Moreover, the model predicts complex shape of the A p E curve and its temperature changes for diluted 1-decanol in n-hexane solutions.