Liquid Phase Equilibrium Research Articles

ТЕРМОДИНАМИЧЕСКИЙ РАСЧЕТ И 3D-МОДЕЛИРОВАНИЕ T-x-y И P(Se2)-T-x ДИАГРАММ В СИСТЕМЕ Сu–Pb–Se ПО ЛИКВИДУСУ PbSe

Впервые с помощью математического аппарата феноменологической термодина-мики гетерогенных равновесий и компьютерной программы OriginLab определены и 3D-мо-делированы T-x-y и P(Se2)-T-x диаграммы системы Сu–Pb–Se по поверхности кристаллизацииселенида свинца. Вычислены парциальные избыточные свободные энергии смешения свинцаи селена, давление насыщенного пара селена для жидких сплавов Сu–Pb–Se, насыщенныхселенидом свинца. Показано, что паровая фаза в основном состоит из двухатомных молекулселена Se2. Для областей ликвидуса PbSe(р-тип)-Se и PbSe(n-тип)-Pb получены следующиезависимости соответственно:lg Se p 2 (Pa) = [–1281 + 5624(1000/T) – 9190(1000/T)2 + 6648(1000/T)3 – 1797(1000/T)4] – 10.35 xCu2 ;lg Se p 2 (Pa) = [2026 – 8778(1000/T) + 14247(1000/T)2 – 10259(1000/T)3 – 2759(1000/T)4] – 8.36 xCu2 .Проведена 3D визуализацияполученных аналитических зависимостей

Determination and thermodynamic modeling of solid–liquid phase equilibrium for the 2,4,6-trimethylphenol and 2,5-dimethylphenol binary system

The solid–liquid phase equilibrium for binary system of 2,4,6-trimethylphenol (TMP) and 2,5-dimethylphenol (DMP) was built by differential scanning calorimeter under atmospheric pressure (101.3 kPa). Two thermodynamic models of Wilson and NRTL were employed to correlate and calculate the experimental data for the system. The mean-root-square error values are 0.1924 and 0.2204. The residual sums of square values are 0.4810 and 0.6315, respectively. Values $$ R^{2} $$ are all larger than 0.9995. The pure TMP, pure DMP and the mixture of them were confirmed by gas chromatography, Raman spectrometer and X-ray diffraction before and after the determination. In addition, the specific heat (Cp) of solid TMP and DMP between 285.15 and 335.15 K and liquid TMP and DMP between 353.15 and 403.15 K were determined at atmospheric pressure.

Kinetic and thermodynamic analysis for the redemption of effluents containing Solochrome Black T onto powdered activated carbon: A validation of new solid-liquid phase equilibrium model

Degeneracy of synthetic dyes by activated carbon is necessary to save environment. The present study aimed at the impact of surface modification of activated carbon with the aid of ultra sound waves to instigate surface properties, exposure time to treat an azo dye, Solochrome Black T. Interference of ultra sound waves on the surface characteristics of activated carbon by SEM-EDX, FT-IR and physical, thermal characteristics by XRD and TGA were examined. Evaluation of batch adsorption was performed by investigating the factors affecting the adsorption process (initial adsorbate concentration, pH, contact time and temperature); adsorption isotherms and kinetics. The estimated adsorption capacity of 4.0gL−1 was 106.7 (mg/g). Thermodynamic studies confessed the method of removal of dye was exothermic and spontaneous. The present adsorption system obeyed Pseudo second order kinetics (R2>0.97). Experimental data was used to validate a new solid liquid phase equilibrium model, showing the average absolute relative deviation 6.682%.

Solid–Liquid Phase Equilibrium in the Ternary System MgSO4 + MgCl2 + H2O at 263.15 K

The stable solid–liquid phase equilibrium in the ternary system MgSO4 + MgCl2 + H2O at 263.15 K was investigated with the isothermal dissolution method, and the phase diagram was plotted. Two isothermal invariant points cosaturated with MgSO4·7H2O + ice and MgCl2·6H2O + MgSO4·7H2O, three stable crystallization fields corresponding to MgCl2·6H2O (Bis), MgSO4·7H2O (Eps), and ice, and three isothermal univariant curves were determined in the ternary system. Compared to the phase equilibrium at 273.15 K, the ice crystallization region and ice–salt invariant point are found at 263.15 K. Neither solid solution nor double salts are found in the system.

Measurement and Correlation of Isobaric Vapor–Liquid Equilibrium for Binary Systems of Allyl Alcohol with Isobutyl Acetate, Butyl Acetate, and Butyl Propionate at 101.3 kPa

For separation of the azeotrope of allyl alcohol and water, three extractive agents—isobutyl acetate, butyl acetate, and butyl propionate—were selected to extract allyl alcohol from the azeotrope. To recover the extractive agents by distillation, the isobaric vapor–liquid phase equilibrium (VLE) data for allyl alcohol + isobutyl acetate, allyl alcohol + butyl acetate, and allyl alcohol + butyl propionate were measured at 101.3 kPa. With the VLE data, there is no azeotrope formed in three systems. The consistency of the measured VLE data was validated by the Herington, infinite dilution, pure component consistency, and van Ness tests. Moreover, the Wilson, UNIQUAC, and NRTL models were used to fit the measured VLE data. All of the calculated results agreed with the VLE experimental data. Meanwhile, the parameters of the Wilson, UNIQUAC, and NRTL were regressed, which can be employed for the development and optimization of the separation process. Furthermore, the VLE data were predicted by the UNIFAC model ...

Comment on “Determination and Thermodynamic Modeling of Solid–Liquid Phase Equilibrium for Esomeprazole Sodium in Monosolvents and in the (Ethanol + Ethyl Acetate) Binary Solvent Mixtures”

Errors are found in several of the mathematical representations in the published paper by Zhao and co-workers. Published curve-fit parameters for several of the modified Apelblat model representations yield back-calculated mole fraction solubilities of esomeprazole sodium that exceed unity. Mole fraction concentrations cannot exceed unity. Back-calculated mole fraction solubilities for a mathematical representation, presumably based on the Jouyban–Acree model, were also found to exceed unity.

Thermal, physicochemical and spectroscopic studies on some novel organic complexes obtained by green synthesis

The solid–liquid equilibrium phase diagram and thermochemical studies on two binary organic systems involving N-methylurea (MU) with 4-nitrophenol (NP) and 3-nitrobenzoic acid NBA were studied. Both systems show the formation of an equimolar intermolecular compound (IMC) and two eutectics (E1 and E2) one on either side of the IMC. Thermodynamic parameters such as heat of mixing, entropy of fusion, roughness parameter, interfacial energy and excess thermodynamic functions of intermolecular compounds and eutectics were calculated using the experimentally determined enthalpy of fusion by the DSC method. The spectroscopic studies, FTIR and NMR, of both the IMCs along with their parent compounds revealed the hydrogen bonding association between the parent moieties forming the complex. The findings were also confirmed by the appearance of new peaks in the powder XRD of the complexes in addition to their parent compounds.

Solid–liquid phase equilibrium and mixing thermodynamic analysis of coumarin in binary solvent mixtures

ABSTRACTThe solubility of coumarin in three aqueous solvent mixtures (methanol + water, ethanol + water and acetone + water) was experimentally determined by a gravimetric method at atmospheric pressure. The experimental solubility data were fitted using the modified Apelblat equation, non-random two-liquid (NRTL) equation, the combined nearly ideal binary solvent/Redlich–Kister equation and the Jouyban−Acree equation, respectively. All the equations were proven to be able to correlate the experimental data, and the modified Apelblat equation could obtain better correlation results than the other three models. The solubility of coumarin increases with increase in temperature. At the same temperature, the solubility increases with increase in mole fraction of organic solvents except for the ethanol–water system which shows a unimodal curve. In addition, the apparent thermodynamic properties of the mixing process were calculated based on the NRTL model and the experimental solubility data.

Vapor Liquid Phase Equilibrium for Azeotropic Isobutane + trans-1,3,3,3-Tetrafluoropropene + Trifluoroiodomethane System at Temperatures from 243.150 to 283.150 K

In this paper, the investigation on the vapor liquid phase equilibrium (VLE) of the ternary system isobutane + trans-1,3,3,3-tetrafluoropropene + trifluoroiodomethane was carried out. The measurements were performed using an apparatus based on the recirculation method at temperatures ranging from 243.150 to 283.150 K. Three models, namely PR-vdW, PR-BM, and PR-MHV2-NRTL, were employed to describe the VLE properties of the system concerned. PR-MHV2-NRTL was the best model, which gave the maximum average absolute pressure relative deviation of 0.85% and the average absolute vapor phase fraction deviation of 0.011. With the regressed binary parameters from ternary VLE data, the binary VLE were well-predicted. A maximum-point ternary azeotropic behavior was exhibited.

Evaluation and correlation of separation heptane/ethanol with ionic liquids. Ternary liquid-liquid phase equilibrium data

The objective of this work was to explore the feasibility of separation of heptane from ethanol using ammonium-based and imidazolium-based ionic liquids (ILs). With this aim, the liquid–liquid phase equilibrium (LLE) for four ternary systems of {IL (1) + ethanol (2) + heptane (3)} at temperature T = 313.15 K and pressure p = 101 kPa were determined. The synthesis of new ammonium-based ionic liquid (IL), N-benzyl-N-dimethyl-N-tetradecylammonium vannilliate, [NBz,1,1,14][Van] has been presented and used in LLE measurements. The results of selectivity of separation were compared to popular N-octyl-N-triethylammonium bis{(trifluoromethyl)sulfonyl}imide, [N8,2,2,2][NTf2], and two imidazolium-based ILs: 1-ethyl-3-methylimidazolium trifluoroacetate, [EMIM[TFA] and 1-hexyloxymethyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [C6H13OCH2MIM][NTf2]. The [EMIM[TFA] IL showed excellent results in terms of selectivity and solute distribution ratio. On the basis of the results, the intermolecular interactions of the chosen ILs and solvents were discussed. The data presented here shows that [NBz,1,1,14][Van] reveals lower selectivity for the heptane/ethanol separation than the other used ILs. It allows expanding our knowledge about nature of the [NBz,1,1,14][Van], influence of polar functional groups and alkane chain in the cation on thermodynamical properties of [NBz,1,1,14][Van]. All experimental data were well correlated with the NRTL model.

Ternary LLE measurements for the separation of hex-1-ene/hexane and cyclohexene/cyclohexane compounds with [DCA]-based ionic liquids

The objective of this work was to explore the feasibility of separation of hex-1-ene from hexane and cyclohexene from cyclohexane with new ionic liquids (ILs) with [DCA]_ anion. With this aim, the liquid–liquid phase equilibrium (LLE) for three ternary systems of {IL (1) + hex-1-ene (2) + hexane (3)} and two {IL (1) + cyclohexene (2) + cyclohexane (3)} at T = 298.15 K were determined at ambient pressure. Three new ILs have been presented and used in LLE measurements: 3-(2-methoxyethyl)-1-methylimidazolium dicyanamide, [(C2OCH3)MIM][DCA], 1-(4-methoxy-4-oxobutyl)-3-methylimidazolium dicyanamide, [(C3COOMe)MIM][DCA] and choline dicyanamide, [Chol][DCA]. The anion of the ILs was chosen after a literature analysis and measurements of activity coefficient at infinite dilution in many ILs. Chosen ILs revealed large selectivity and very low solute distribution ratio. The results of the chromatography analysis indicated that the ILs used as an entrainers were not detected in the hydrocarbon-rich layer, which is convenient, because eliminates the step needed for the separation of the solvent. The well known NRTL activity coefficient model was used to correlate the LLE data.

Liquid–liquid–solid mass transfer and phase behavior of heterogeneous etherification of glycerol with isobutene

Previous experiments observed auto‐acceleration in the etherification of glycerol with isobutene. This article engaged to uncover the reason for this phenomenon via investigating the heterogenicity, including liquid–liquid phase equilibrium and liquid–liquid–solid mass transfer, of the reaction system. Phase behavior analysis showed that the reaction mixture separates into two liquid phases during the whole course of the reaction. The produced mono ethers of glycerol thermodynamically promote the homogenization of the two liquid phases. The modeling results of liquid–liquid–solid mass transfer indicated that the resistance of mass transfer is insignificant during the reaction. The bulk compositions of the two liquid phases are very close to their corresponding equilibrium compositions. An increase of isobutene concentration in the reaction phase is believed to lead all reactions speeding up. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2526–2535, 2018

Unravelling the structural and dynamical complexity of the equilibrium liquid grain-binding layer in highly conductive organic crystalline electrolytes

A nanolayer of surface liquid phase in equilibrium with the bulk solid is responsible for the low grain boundary resistance in the solid electrolyte LiCl·DMF, as supported by a combination of experiment, theory, and modelling.

Liquid-liquid phase equilibrium and the effect of a water-soluble polymer on the interaction between droplets in water-in-oil microemulsions.

The liquid-liquid phase equilibria of {water/PEG200/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/n-decane} with the molar ratio of water to AOT being 37.9 and various concentrations cPEG of PEG in water were measured in this study. The critical exponent β corresponding to the width of the coexistence curve was determined, which showed good agreement with the 3D-Ising value and supported the proposal of the pseudo binary droplet solution for these multiple microemulsions. A previously developed thermodynamic approach based on the Carnahan-Starling-van der Waals type equation was improved and used to analyze the coexistence curve data of {water/PEG200/AOT/n-decane} microemulsions to deduce the interaction properties between droplets and further to investigate the effect of the additive PEG200 on these interactions. It was found that the addition of PEG200 into the {water/AOT/n-decane} microemulsion resulted in the decrease in the critical temperature and the interaction enthalpy and entropy. Both the interaction enthalpy and entropy decreased first, then increased with an increase of cPEG and had minimum values at cPEG = 25 g L-1, which showed the same tendency as the isothermal titration microcalorimetric results for the {water/PEG200/AOT/isooctane} microemulsion we reported very recently. The effects of the interaction enthalpy and the entropy on the phase separation and their dependences on cPEG were discussed and related to the effects of the additive on the rigidity of the interface layer of the microemulion droplet.

Electric Conductivity of Delaminated AgI + NaCl Mixture

The liquid–liquid phase equilibrium for the melted AgI + NaCl mixture was studied by the impedance method over a wide range of temperatures along the saturation line to correlate the charge transfer in two-phase ion systems with the nature of the chemical bond. The temperature dependences of the specific electric conductivity κ of the coexisting phases have opposite signs because of the superposition of the temperature and concentration factors that act in the same or opposite directions. The difference between the κ values for the equilibrium phases decreases with increasing temperature, becoming zero at 1064 K. Near the critical mixing point, the temperature dependence of the difference between the conductivities of the coexisting phases is described by the exponential equation with a critical exponent of 0.91, which is 8% smaller than that found for alkali metal halides with primarily Coulomb forces acting between the ions.

Transport properties and thermodynamic characterization of aqueous solutions of morpholinium - based ionic liquids

In this work, the systematic studies of the physical and thermodynamic properties of two binary systems involving morpholinium-based ionic liquids, that is: N-ethyl-N-methyl-morpholinium acetate, [EMMOR][AcO] and N-ethyl-N-methylmorpholinium propionate, [EMMOR][Pro] with water are reported. Synthesis of new carboxylate - based ionic liquids (ILs) were performed in our laboratory and the structures were confirmed by nuclear magnetic resonance spectroscopy, NMR and elementary analysis. Basic thermophysical properties that is: the glass transition temperature, Tg,1 and heat capacity at glass transition temperature, ΔCp(g) were determined by the differential scanning calorimetry (DSC) technique. The measurements of density, ρ and dynamic viscosity, η over the entire concentration range at temperatures from (298.15 to 348.15) K with 5K intervals have been done at pressure p=100kPa. From experimental data, excess molar volumes, VE and dynamic viscosity deviations, Δη were calculated using Redlich - Kister equation. The mutual solubility of the tested ILs with water have been determined using dynamic method. The isothermal vapor − liquid phase equilibria, VLE have been measured by an ebulliometric method within temperature range from (328.15 to 368.15) K and pressure up to 100kPa. Phase equilibrium data have been correlated using the NRTL equation. The influence of the anion structure on the presented transport and thermodynamic properties is presented and discussed.

Investigation of real gas effects on combustion and emissions in internal combustion engines and implications for development of chemical kinetics mechanisms

Real gas effects on combustion and emissions in internal combustion engines are investigated using three-dimensional computational fluid dynamics. The Peng–Robinson equation of state is implemented to describe pressure–volume–temperature relationships and to calculate thermodynamic properties and relevant partial derivatives. Four facilities are modeled, including non-reacting compression in a motoring engine, combustion in a conventional diesel combustion engine and in a reactivity controlled compression ignition engine, as well as for a non-reacting reflected wave in a shock tube. It is found that the real gas effects of gas mixtures in practical internal combustion engine operation are sensitive to the operating load and the amount of premixed fuel. Excellent agreement against experiments was found for engine simulations with the Peng–Robinson equation of state in terms of cylinder pressure and apparent heat release rate. However, discrepancies with predictions from the ideal gas law grow with increased load and larger amounts of premixed fuel. In particular, the predicted emissions of soot, NOx, CO and unburnt hydrocarbons show increasing sensitivity to real gas effects as a result of changes in combustion phasing. Fuel condensation is also modeled using a vapor–liquid phase equilibrium solver and significant dependency on the equation of state used is found. Therefore, it is recommended to include real gas effects in internal combustion engine modeling to capture combustion and emissions characteristics accurately. Additionally, the results emphasize the role of real gas effects on reaction rates. Shock tube simulations are used to demonstrate the importance of using the real gas equation of state in the interpretation of chemical kinetic measurements. Significantly different compressed gas temperatures behind the reflected shock are predicted when real gas effects are considered. This needs to be realized when developing chemical kinetic models and rate constants for engine applications from shock tube data.

Characterization of the Solid Residue and the Liquid Extract Separated by Propane-Induced Crude Oil Fractionation

Following a previously reported experimental procedure, a heavy petroleum sample was fractionated by mixing a predefined volume of oil with liquid propane above its saturation pressure at different propane/oil ratios. The separated fractions, considered two mutually saturated liquid phases in equilibrium at p and T separation conditions, were denominated solid residue and liquid extract and were characterized by chemical and spectroscopic methods including elemental compositional and SARA analyses, FTIR, and NMR. The results show that the amount yielded or produced increases for the solid residue and decreases for the liquid extract as the propane/oil ratio increases and that the four SARA components are present in both fractions, independently of the propane/oil ratio used in the fractionation process. The data also indicate that polar components are present in the liquid extract even at the highest dilutions that correspond to rather low solubility parameters. Complementary results show that after the f...

Separation of Azeotropes Hexane + Ethanol/1-Propanol by Ionic Liquid Extraction: Liquid–Liquid Phase Equilibrium Measurements and Thermodynamic Modeling

To separate the azeotropes of hexane + ethanol/1-propanol, two ionic liquids [HMIM][BF4] and [HMIM][OTf] were adopted as extractive agents. The corresponding ternary liquid–liquid equilibrium data for the mixtures of hexane + ethanol + [HMIM][BF4], hexane +1-propanol + [HMIM][BF4], and hexane +1-propanol + [HMIM][OTf] were measured at 298.15 K and 101.3 kPa. The distribution coefficient (B) and selectivity (S) were obtained to evaluate the separation performance of the selected extractants to extract ethanol/1-propanol from the azeotropes. Meanwhile, the influence of the ILs’ anions and the alcohol carbon chain length were investigated. In addition, the nonrandom two-liquid (NRTL) and universal quasichemical activity coefficient (UNIQUAC) models were adopted to correlate the ternary liquid–liquid equilibrium data, and the binary interactive parameters were regressed. Also, the calculated results of the models agreeed with the measured data. Meanwhile, the binodal curves of the ternary systems were predict...

Solid–Liquid Phase Equilibrium and Thermodynamic Properties of Olaparib in Selected Organic Solvents and (Tetrahydrofuran + MTBE, Acetonitrile + Isopropyl Alcohol) Binary Solvent Mixtures

We focused on the solubility of olaparib under atmospheric pressure in isopropyl alcohol, MTBE, acetonitrile, and tetrahydrofuran as well as in the (tetrahydrofuran + MTBE, acetonitrile + isopropyl alcohol) mixtures from 280.35–319.35 K. It is found that the solubility of olaparib and temperature were positively correlated in the range of our study. We chose the modified Apelblat equation, the Buchowski–Ksiazaczak λh equation, CNIBS/R-K equation, and the Jouyban–Acree equation to verify the thermodynamic properties of olaparib. Computational results showed that all selected equations agreed well with the experimental data, and the modified Apelblat equation gives the best correlation. We also selected two binary solvent dissolution systems, and the test found that (tetrahydrofuran + MTBE) mixtures may be a good recrystallization system. This study provides valuable data for olaparib’s production process purification.