Coefficient Of Excess Molar Enthalpy Research Articles

Application of ERAS-model and PFP theory on excess and deviation properties for binary systems of ionic liquid + amine derivatives

Thermodynamics of mixtures includes ionic liquid 2-hydroxyethylammonium propionate [2-HEAPr] + 1-propanol, 3-amino-1-propanol [AP], 1-amino-2-propanol [MIPA], and monoethanolamine [MEA] were studied. Density ρ, speed of sound u, and refractive index nD of pure and mixtures were measured at T = (298.15, 308.15, 318.15) K. Excess molar volume VmE, excess partial molar volume Vm,iE, excess thermal expansion coefficient αE, isothermal coefficient of excess molar enthalpy (∂Hm∂P)T,x, deviations in isentropic compressibility Δ ks, and refractive index Δ nD were calculated and data correlated with Redlich-Kister polynomial relation. The Prigogine-Flory-Patterson (PFP) and Extended Real Associated Solution (ERAS) models were applied to analyze intramolecular and intermolecular interactions between like and unlike molecules. The accuracy of theoretical models were found to be in agreement with empirical results. Finally, the study confirmed the structures of the ILs using FT-IR and HNMR analysis.

Experimental, theoretical and computational study of binary systems of alkanolamines and alkylamines with cyclohexanol at different temperatures

Density, ρ, speed of sound, u, and the difference in the temperature before and after the mixing process , ΔT, were measured for binary mixtures containing of cyclohexanol (CYC) + diethanolamine (DEA) or triethanolamine (TEA) or butylamine (BUT) or hexylamine (HEX) at (303.15–318.15) K except ΔT at 303.15 K. The excess molar volume, VmE, excess partial molar volume, Vm,iE, excess thermal expansion coefficient, αE, isothermal coefficient of excess molar enthalpy,(∂HmE∂P)T,x, deviation in isentropic compressibility,Δκs, excess molar enthalpy,HmE, and excess partial molar enthalpy, Hm,iE, were also calculated. The calculated data were satisfactorily correlated by Redlich – Kister equation. Some empirical models such as (Prigogine–Flory–Paterson) PFP, Wilson, (Non-Random Two Liquid) NRTL and (universal quasi chemical) UNIQUAC. Computational methods were performed using density function theory (DFT) and molecular dynamics (MD) simulation and were used to discuss and compare intramolecular and intermolecular interactions. An acceptable agreement was found between empirical and theoretical data.

Thermodynamic study of binary mixture of 2-butanol + monoethanolamine at different temperatures; PC-SAFT and ERAS models

In this paper, to study the possible intermolecular interactions in the binary mixtures 2-butanol with monoethanolamine, values of density were measured at temperatures 293.15 to 323.15 K and atmospheric pressure (P = 0.0815 MPa). From experimental densities, values of excess molar volume, VmE thermal expansion coefficient, α excess thermal expansion coefficient, αE and isothermal coefficient of excess molar enthalpy, (∂HmE/∂P)T, x were calculated. Excess molar volume is negative for the mentioned binary mixture over the whole range of concentration and becomes more negative with the increase in the temperature. ERAS model with the six adjustable parameters was used to correlate the excess molar volumes at different temperatures. Agreement between experimental data and predicted values through this model was reasonable at all temperatures. The maximum standard deviation for the mentioned binary mixture was 1%. Also, PC-SAFT model with one adjustable parameter and different schemes (2B, 3B, 4C) was applied to correlate the binary densities. A comparison among the performance of three approaches shows that the scheme 3B-2B at 293.15 K with the average absolute deviation (AAD) 1.63% has the best agreement with experimental data. When the PC-SAFT model with the prediction ability (p = 0) was implemented, the minimum of AAD increased to 4.66%.

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.

Non-ideal behavior of ethanol + amines mixtures, modeling using the Peng-Robinson and PC-SAFT equation of state

In this paper, experimental measurements of densities and viscosities of Ethanol + Diethylenetriamine (DETA) or Aminoethylethanolamine (AEEA) binary liquid mixtures are reported at temperatures of 298.15, 303.15 and 308.15K and atmospheric pressure over the whole composition range. From the experimental data, excess molar volume, excess coefficient of thermal expansion, excess partial molar volume, isothermal coefficient of excess molar enthalpy, excess Gibbs free energy of activation and excess viscosity were calculated. The sign and magnitude of excess quantities were used to discuss about the nature and strength of molecular interactions in these solutions. The obtained excess molar volumes were correlated with Redlich-Kister polynomial equation. Moreover, the measured values of densities were predicted with Peng-Robinson and PC-SAFT equation of states and the experimental values of viscosities were correlated and predicted by different semi-empirical equations.

Isobaric, isothermal theoretical investigation and examination of different prediction equations on some physicochemical properties in PEG liquid polymer system

Densities, viscosities and refractive indices of the {poly(ethylene glycol) 200+ethanol} binary liquid system were determined at three temperatures of (298.15, 303.15, and 308.15)K. From the experimental results, the excess molar volume was obtained and correlated with the Prigogine–Flory–Patterson (PFP) and Extended Real Associated Solution (ERAS) models. Several isobaric and isothermal properties consisting of the isobaric thermal expansion coefficient, excess molar isobaric expansion, excess molar isobaric heat capacity, isothermal coefficient of excess molar enthalpy, activation energy of flow, electron polarizibility, and Gibbs energy of activation were calculated from the experimental measurements. Moreover, the viscosity and refractive index values were correlated and predicted with different semi-empirical equations. To assess the validity of these proposed equations, comparisons were made between the experimental and predicted values.

Volumetric and acoustic properties of binary mixtures of cyclohexane + benzene and + benzaldehyde at (293.15–323.15) K

Densities ρ of and speeds of sound u in binary mixtures cyclohexane+benzene and+benzaldehyde have been measured over the entire range of composition at atmospheric pressure and at temperatures ranging from (293.15 to 323.15) K using an Anton-Paar DSA 5000. From these data molar isentropic compressibilities KS,m, thermal expansion coefficients αP, excess molar volumes VmE, and excess molar isentropic compressibilities KS,mE at all the temperatures, and excess thermal expansion coefficients αPE and isothermal pressure coefficient of excess molar enthalpy (∂HmE/∂P)T,x at 298.15K were calculated. The VmE for both the mixtures are positive at all temperatures and over entire range of compositions. The KS,mE are positive over entire composition for cyclohexane+benzene while KS,mE curve is S-shaped for cyclohexane+benzaldehyde. The values of αPE are negative except for cyclohexane rich region in both the mixtures. The values of all the excess functions are lower for cyclohexane+benzaldehyde as compared to cyclohexane+benzene at all the temperatures and compositions.

Experimental excess molar properties of binary mixtures of (3-amino-1-propanol + isobutanol, 2-propanol) at T = (293.15 to 333.15) K and modelling the excess molar volume by Prigogine–Flory–Patterson theory

Density and viscosity of binary mixtures of (x13-amino-1-propanol+x2isobutanol) and (x13-amino-1-propanol+x22-propanol) were measured over the entire composition range and from temperatures (293.15 to 333.15)K at ambient pressure. The excess molar volumes and viscosity deviations were calculated and correlated by the Redlich–Kister (RK) equation. The thermal expansion coefficient and its excess value, isothermal coefficient of excess molar enthalpy, and excess partial molar volumes were determined by using the experimental values of density and are described as a function of composition and temperature. The excess molar volumes are negative over the entire mole fraction range for both mixtures and increase with increasing temperature. The excess molar volumes obtained were correlated by the Prigogine–Flory–Patterson (PFP) model. The viscosity deviations of the binary mixtures are negative over the entire composition range and decrease with increasing temperature.

The excess molar properties of {x1[C6min][BF4] + x22-propanol}: Application of ERAS model

Density, ρ, and viscosity, η, of pure 1-hexyl-3-methylimidazoliumtetrafluoroborate ([C6mim][BF4]), 2-propanol, and binary mixture of {x1[C6mim][BF4]+x22-propanol} were measured at atmospheric pressure and in the temperature range of (293.15 to 333.15) K. The excess molar volume, VmE, thermal expansion coefficient, αp, excess thermal expansion coefficient, αpE, and isothermal coefficient of excess molar enthalpy (∂HmE/∂p)T, x, were calculated from the experimental values of density. The excess molar volumes are negative over the entire mole fraction range for this mixture and increase with increasing temperature. These data have been used to examine the applicability of Extended Real Associated Solution (ERAS) model in correlating the excess molar volume of the binary mixture. The viscosity values of the binary mixture were calculated via McAllister equation and the obtained results show a good agreement between the experimental and the calculated values in the whole composition range and all temperatures, so that the relative deviations are rarely more than 2%. The excess molar properties were correlated with the Redlich–Kister equation.

Measurement and modeling the excess molar properties of binary mixtures of {[C6mim][BF4] + 3-amino-1-propanol} and {[C6mim][BF4] + isobutanol}: Application of Prigogine–Flory–Patterson theory

In this work, densities, ρ, and viscosities, η, of pure 1-hexyl-3-methylimidazoliumtetrafluoro borate {[C6mim][BF4]}, 3-amino-1-propanol (AP), and isobutanol, along with their binary mixtures of {x1[C6mim][BF4]+x2AP} and {x1[C6mim][BF4]+x2isobutanol} were measured over entire composition range at ambient pressure (81.5kPa) and in the temperature range of (303.15 to 338.15)K. The excess molar volume, VmE, thermal expansion coefficient, α, and its excess value, αE, isothermal coefficient of excess molar enthalpy, (∂HmE/∂p)T,x, and viscosity deviation, Δη, for both of the mixtures were calculated from the experimental values of densities and viscosities. The values of VmE for binary mixture of {x1[C6mim][BF4]+x2AP} shows a S-shaped dependence on composition with positive values in the [C6mim][BF4] rich-region and negative values at the opposite extreme, and increase with increasing temperature. This quantity is negative for binary mixture of {x1[C6mim][BF4]+x2isobutanol} in the entire composition range and increases with increasing temperature. Viscosity deviations, Δη, are negative over the entire composition range and decrease with increasing temperature for both of the mixtures. These data were correlated by Treszczanowiczb–Benson and Redlich–Kister equations, and the fitting parameters and standard deviations were determined. The Prigogine–Flory–Patterson theory has been used to correlate the excess molar volumes of the mixtures.

Thermodynamic study of binary mixture of x1[C 6mim][BF 4] + x21-propanol: Measurements and molecular modeling

Densities, ρ, and viscosities, η, of pure 1-hexyl-3-methylimidazoliumtetrafluoro borate ([C 6mim][BF 4]) and 1-propanol, and their binary mixture { x 1[C 6mim][BF 4] + x 21-propanol} were measured at atmospheric pressure and in the temperature range of 293.15–333.15 K. The excess molar volumes, V m E , thermal expansion coefficients, α, and their excess values, α E , isothermal coefficient of excess molar enthalpy, ( ∂ H m E / ∂ p ) T , x and excess viscosities, η E , were calculated from the experimental values of densities and viscosities. The excess molar volumes of the binary mixture are negative over the entire mole fraction range and increase with increasing temperature. Excess viscosities are negative over the entire mole fraction range of the mixture and decrease with increasing temperature. The obtained excess molar volumes and excess viscosities were correlated with the Redlich–Kister equation. The experimental results have also been used to examine the applicability of Prigogine–Flory–Patterson (PFP) theory in predicting the excess molar volume of the binary mixture. It is indicated that agreement between excess molar volumes calculated via PFP theory and the experimental results is good in all temperatures.

Excess molar volume and derived thermodynamic properties of binary mixtures of 2-methyl-1-butanol and 2-ethyl-1-butanol + different ethers at the temperature range of 293.15 to 313.15 K

Densities of the binary liquid mixtures of 2-ethyl-1-butanol + dibutyl ether (DBE) or ethylene glycol mono butyl ether (EGMBE), 2-methyl-1-butanol + DBE, have been measured as a function of the composition at temperature range of 293.15 to 313.15 K and atmospheric pressure. The measurements have been carried out using an Anton Paar model DMA 4500 oscillating u-tube densitometer. The excess molar volume, V m E, the excess thermal coefficient, α E, and the isothermal expansion coefficient of excess molar enthalpy, (∂ H m E/∂ P) T,x , were calculated from the experimental densities. It is indicated that the excess molar volume is negative for 2-methyl-1-butanol + DBE over the entire mole fraction range, and decreases with increasing temperature. The V m E value is positive for the binary mixture of EGMBE + 2-ethyl-1-butanol over the entire mole fraction range, and decreases with increasing temperature. This quantity is negative for the binary mixture of 2-ethyl-1-butanol + DBE over the entire mole fraction range, and decreases with increasing temperature in the limit of pure ether and increases with increasing temperature in the limit of pure alcohol. The excess molar volumes were correlated with Redlich–Kister equation.