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General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Experimental measurement, Ionic liquid, Methane hydrate equilibrium, and Phase behavior modeling

In this study, the equilibrium conditions of methane hydrate is measured experimentally in the presence of 1-ethyl-3-methyl-imidazolium chloride ([EMIM]-C) and 1-hydroxylethyl-3-methyl-imidazolium chloride ([OH-C2MIM]-Cl) solutions. These two ionic liquids are chosen to study their performances as low dosage hydrate inhibitors. To study the effect of these ionic liquids on the equilibrium phase boundary of methane hydrate, several experiments are conducted in a pressure range of 4-12 MPa. In addition, the equilibrium data in [EMIM]-Cl solutions are modeled using an equation that takes into account the effects of electrolyte on the activity of water. Results show that phase boundary of methane hydrate is shifted toward lower temperature at constant pressure from 0.1 to 1.5 K in the presence of these ionic liquids. This temperature shift, however, becomes more significant at pressures higher than 70 MPa.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Heat capacity, Ionic liquids, Simple correlation, and Validation tests

Ionic liquids, owing to their unique characteristics grasp many researchers' attention in both academia and industrial fields. In this communication, the attention is focused on the heat capacity of ionic liquids, as one of the most basic and important thermophysical properties. The simple 5-term temperature dependent correlation based on basic molecular parameters is presented to predict heat capacities of ILs. A total data set of 2940 experimental data belonging to 56 ionic liquids was used to develop a general correlation. The global absolute average deviation of the model results from experimental values is 2.5%. The proposed model could be safely applied for thermodynamic and industrial applications.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Electrolyte models, LIFAC, LIQUAC, Mean activity coefficients, Salt solubility, and Thermodynamics

The reliable knowledge of the thermodynamic behavior plays a major role for the design of different industrial processes. A lot of thermodynamic models do not incorporate electrolyte solutions. For these systems special models have been published. However a lot of these models suffer from the fact that highly concentrated electrolyte solutions cannot be calculated with the desired accuracy which leads to problems when calculating, e.g. salt solubilities. In this article, a revised LIQUAC and LIFAC model is presented, which enables the user to describe mean activity coefficients, osmotic coefficients and also vapor-liquid equilibria reliably. Furthermore the prediction of salt solubilities in aqueous solutions and mixed solvents can be performed successfully. In this paper the predicted data are compared with published data stored in the Dortmund Data Bank. The improvements achieved are additionally shown by a comparison with the results of the original LIQUAC and LIFAC model.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Activity coefficients, Chemical constraints, Liquid-liquid equilibrium, Organic-electrolyte mixtures, and Phase separation algorithm

Liquid mixtures containing a variety of organic compounds, water, and dissolved electrolytes are prone to liquid-liquid phase separation, owing to non-ideal interactions between water, ions, and organic compounds. Such systems are of practical importance in the design of chemical separation processes as well as the partitioning of semivolatile species in atmospheric aerosols. In this study, a practical phase separation calculation method based on a system of nonlinear equations is presented, applicable to multicomponent systems containing inorganic ions. Expressions are derived that allow consistent use of activity coefficients defined on molality basis for ionic species in combination with mole fraction-based activity coefficients for nonelectrolyte components. Physicochemical considerations are applied together with preliminary evaluation of generated trial compositions to automatically obtain a set of feasible initial guesses. A successive substitution procedure with component-specific step length damping is then employed, followed by a rapid convergence part using a globally convergent solver for systems of nonlinear equations. We discuss several examples that demonstrate the method's remarkable level of reliability even in the case of systems showing highly non-ideal mixing behavior, and we highlight the importance of providing a good initial guess.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Critical amplitudes, Critical point, Isochoric heat capacity, Liquid-gas coexistence curve, Singular diameter, Vapor-pressure, Yan-Yang anomaly strength, and n-Butanol

The PVT and CVVT properties ofn-butanol have been measured in the near- and supercritical regions. Measurements of PVTrelation for n-butanol was made along 6 liquid and vapor near-critical isochores in the density range from (113.76 to 470.00) kg m―3 and at temperatures from (497 to 616) K and at pressures up to 10 MPa. The measurements were performed with a constant-volume piezometer technique. Caloric (CVVT) properties of n-butanol were measured along the critical isochore and coexistence curve (liquid and vapor branches) in the one- and two-phase regions. The temperatures, densities, and pressures at the liquid-gas boundary curve (PS. Ts. ps) and the critical parameters (TC = 563.05 ± 0.2 K, PC = 4.405 ± 0.01 MPa, ρC = 270.0 ± 2 kg m―3) for n-butanol were obtained using the isochoric (P―T) break-point and quasi-static thermograms (CV jumps) techniques. The expanded uncertainty of the density, pressure, and temperature measurements at the 95% confidence level with a coverage factor of k=2 is estimated to be 0.10% (at high densities) to 0.12% (at low densities), 0.0005-0.005 MPa, and 15 mK, respectively. The total experimental uncertainty of isochoric heat capacity (CV) measurements were estimated to be 2-3%. The measured Cv, PVT, saturated density (ρS. TS) and vapor-pressure (Ps. Ts) data near the critical point have been analyzed and interpreted in terms of extended scaling equations for the selected thermodynamic paths (critical isochore, critical isotherm, and coexistence curve) to accurately calculate the values of the asymptotic critical amplitudes (A±0, Γ±0, D0, B0) and to check their universal ratios. The measured saturated density data of n-butanol near the critical point were also interpreted in terms of the complete scaling theory of critical phenomena. In particularly, the contributions of the incomplete, B2t1-α, and complete scaling, B4t2β, terms on the coexistence-curve singular diameter were estimated. The values of the asymmetry parameters a3 and b2 of the coexistence curve singular diameter have been calculated. The strength of the Yang-Yang anomaly Rμ for n-butanol was estimated using asymmetry parameters a3 and the contributions of the second temperature derivatives of vapor-pressure, (d2PS/dT2), and chemical potential, (d2μ /dT2), in the singularity of two-phase isochoric heat capacity, CV2. The measured values of saturated one- (CV1', CV1) and two-phase (CV2', CV2) liquid and vapor isochoric heat capacities and saturated density data (ρS, TS) together with measured vapor-pressure (PS, TS) data were used to calculate other derived thermodynamic properties, such as KT, ΔHvap, CP, Cs, W, (∂P/∂T)V', (∂V/∂T)P', (d2PS/dT2), and (d2μ/dT2) of n-butanol at saturation near the critical point. The results were compared with the direct measurements of these properties.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Liquid-liquid equilibrium, NRTL model, Phosphoric acid, and UNIQUAC model

This study demonstrates the experimental solubility and tie-line data for (water + phosphoric acid + isoamyl acetate or methyl isoamyl ketone) ternary systems at T=(298.2, 308.2, and 318.2)K and atmospheric pressure for the first time. The concentration of each phase was determined by acidimetric titration, the Karl Fischer technique, and refractive index measurements. The experimental tie-line data were correlated using the UNIQUAC and NRTL models. The reliability of the experimental data was determined through the Othmer-Tobias and Hand plots. Distribution coefficients and separation factors were evaluated over the immiscibility regions.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, CO2 loading, MEA-MDEA aqueous solution, and Surface tension

Surface tensions of CO2 unloaded and CO2 loaded MEA-MDEA aqueous solutions were measured by using the BZY-1 surface tension meter, which employs the Wilhemy plate principle. For CO2 unloaded solutions, the temperatures ranged from 293.15 to 333.15 K, and the mass fractions of MEA (wMEA) and MDEA (wMDEA) respectively ranged from 0.05 to 0.20, and 0.05 to 0.45. For CO2 loaded solutions, the temperatures ranged from 293.15 to 323.15 K, and wMEA and wMDEA respectively ranged from 0.05 to 0.10 and 0.30 to 0.45. The uncertainty of the surface tensions is ±0.1 mN m―1. A model was proposed to correlate the surface tensions of both CO2 loaded and CO2 unloaded solutions. For CO2 unloaded MEA-MDEA solutions, with 3 adjustable parameters as input, the average relative deviation (ARD) between experiments and calculations is 1.63%. For CO2 loaded MEA-MDEA solutions, with 5 adjustable parameters as input, ARD is 1.76%. The temperature, mass fractions of amines and CO2 loading dependence of the surface tensions were demonstrated on the basis of experiments and calculations.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, 1,2-Dichloroethane, Aliphatic ethers, Cyclic ethers, Excess enthalpies, and Polyethers

Excess molar enthalpies, HE, for the binary mixtures of 1,2-dichloroethane (1,2-DCE) with diethyl ether (DEE), methyl 1,1-dimethylethyl ether (MTBE), diisopropyl ether (DIPE), 1,3-dioxolane (1,3-DIOXO),1,4-dioxane (1,4-DIOXA), tetrahydropyran (THP), ethylene glycol dimethyl ether (EGDME), diethylene glycol dimethyl ether (DEGDME), and diethylene glycol diethyl ether (DEGDEE), have been measured at 298.15 K and atmospheric pressure, using a Setaram Tian-Calvet C80 microcalorimeter. All the binary systems investigated are characterized by exothermic mixing over the entire composition range, except for 1,2-DCE + DIPE which presents a S-shape HE behavior. The experimental HE data have been fitted to the Redlich-Kister polynomial equation.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, CPA, Glycol, Methanol, Vapor-liquid equilibrium, and Vapor-liquid-liquid equilibrium

Liquid-liquid equilibria data for two binary and two ternary systems are reported in the temperature range of 303.15-323.15 K at atmospheric pressure. The binary systems measured are n-nonane + MEG and ethylbenzene+MEG and the ternary systems are n-nonane + MEG + water and ethylbenzene + MEG + water. These data are satisfactorily correlated (binaries) and predicted (ternaries) using Cubic Plus Association (CPA) equation of state (EoS). CPA is also applied to binary LLE of aromatic hydrocarbon + water and VLE of methane + methanol. Finally the distribution of water and inhibitors (methanol and MEG) in various phases is modeled using CPA. The hydrocarbon phase consists of mixture-1 (methane, ethane, n-butane) or mixture-2 (methane, ethane, propane, n-butane, n-heptane, toluene and n-decane). CPA can satisfactorily predict the water content in the gas phase of the multicomponent systems containing mixture-1 over a range of temperatures and pressures. Similarly the methanol content in the gas phase of mixture-1 + water + methanol systems is predicted satisfactorily with accuracy within experimental uncertainty. For VLLE of mixture-2 + water, mixture-2 + MEG + water and mixture-2 + methanol + water systems, the organic phase compositions are satisfactorily predicted whereas modeling results are relatively less satisfactory for the vapor phase compositions partially due to uncertainties in the experimental data.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Chemical equilibrium, Cuckoo Search, Phase equilibrium, Phase stability analysis, and Stochastic global optimization

In this study, Cuckoo Search is introduced for performing phase equilibrium and stability calculations for the first time. Cuckoo Search is a population-based method that mimics the reproduction strategy of cuckoos. This meta-heuristics have been successfully used for solving some engineering design and optimization problems with promising results. However, this emerging optimization method has not been applied in chemical engineering problems including thermodynamic calculations. This study reports the application of Cuckoo Search and its modified version for phase equilibrium and stability calculations in both reactive and non-reactive systems. Performance of this nature-inspired optimization method has been analyzed using several phase stability, phase equilibrium and reactive phase equilibrium problems. Results show that Cuckoo Search offers a reliable performance for solving these thermodynamic calculations and is better than other meta-heuristics previously applied in phase equilibrium modeling.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Compressed gas model, Polycyclic aromatic hydrocarbons, Prediction, Reference solubility, and Supercritical fluid

The solubilities of some polycyclic aromatic hydrocarbons (PAHs) in supercritical fluids were correlated and predicted using the compressed gas model and the reference solubilities. By introducing the reference solubilities, the compressed gas models combined with Peng-Robinson equation of state, Carnahan-Starling-van der Waals hard sphere equation of state and van der Waals one-parameter mixing rules can yield the overall averages of the average absolute relative deviations (AARDs) of 7.45% and 8.16% in solubility correlation for PAHs in supercritical fluids, respectively, which are much less than the values obtained using the compressed gas model combined with the corresponding equation of state and the sublimation pressures of the solutes. By introducing the reference solubilities, the calculated solubilities are not sensitive to the binary interaction parameters and the solubilities of PAHs in the corresponding supercritical fluid can be predicted with a specific binary interaction parameter. When using reference solubilities in the compressed gas model, the two equations of state provide comparable average AARDs in solubility prediction for PAHs in supercritical fluids, which are 14.00% and 14.19%, respectively. The introduction of reference solubilities into the compressed gas model provides a feasible and simple solubility prediction method for the compounds in supercritical fluids without using their sublimation pressures. Moreover, combined with the reference solubilities and the compressed gas model, the hard sphere equation of state provides a more simple method to predict the solubilities of solutes in supercritical fluids with only their solid molar volumes.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Activity coefficient model, Concentration dependent surface area parameter, Local fraction, and Quasi chemical

A new model is proposed for the calculation of activity coefficients. The proposed model is based on the quasi-chemical theory. The surface area parameters in the model depend on partner molecules and concentrations. The surface area parameters for pure components are cited from the surface area parameters of UNIQUAC model. The number of fitting parameters are three for each binary system in the model. These are q∞21 (surface area parameter of component 1 in component 2 at infinite dilution), q∞12 (surface area parameter of component 2 in component 1 at infinite dilution), and τ12 (interaction parameter) for component (1)+component (2) binary system. The activity coefficients of multi-component systems can be calculated with the binary parameters of constituting binary systems. The calculated results by the model are in good agreement with the experimental data of vapor-liquid and liquid-liquid equilibria for binary systems. The ternary liquid-liquid equilibria are calculated by using the binary parameters of constituting binary systems. The calculated results by the model are much better than those by NRTL and UNIQUAC models.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Bisphenol-A polycarbonate, COSMO-SAC, Ethylene-co-vinyl acetate, Group contribution, Molecular dynamics, Polymer, and Polyvinyl alcohol

Solubility parameters (SP) of three polymers have been estimated and compared with both experimental values. The methods employed for the estimation are: traditional group contribution procedures (Fedors and van Krevelen), molecular dynamics simulation to calculate cohesive energy density and extension of the COSMO-SAC thermodynamic model to polymer mixtures. The aim of the paper is accurately predicted polymer solubility parameters showing differences between methods. Selected polymers have been polyvinyl alcohol (PVA), ethylene-co-vinyl acetate (EVA) and bisphenol-A polycarbonate (PC).

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Ethylene, Experimental measurements, Gas hydrates, Methane, Propylene, Thermodynamic model, and Water

Light olefins such as ethylene and propylene are widely used in industry and combined with water and the correct thermodynamics conditions can form hydrates. In this paper, we report the results of new experimental measurements on the locus of incipient hydrate-liquid water-vapour curve for pure ethylene, propylene, ethylene + propylene, methane + propylene and ethylene + ethane systems. Two different thermodynamic approaches were employed to investigate the phase behaviour of pure olefins and mixed systems: the Valderama―Patel―Teja (VPT) equation of state combined with the non-density-dependent (NDD) mixing rules and the Cubic-Plus-Association equation of state. In both cases, the hydrate-forming conditions are modelled by the solid solution theory of van der Waals and Platteeuw. The parameters of the thermodynamic model were regressed using ethylene and propylene solubility in water and the hydrate dissociation point data of simple hydrates. The developed model was used to predict the hydrate dissociation conditions of the systems investigated in this work. Predictions of the developed model are validated against independent experimental data and the data generated in this work. A good agreement between predictions and experimental data is observed, supporting the reliability of the developed model.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Adaptive neuro-fuzzy model, Affine model, Asphaltene deposition, Permeability, and Pressure drop

Deposition of asphaltene is recognized as a well-known severe problem, which can significantly affect oil production and enhanced oil recovery processes through mechanism of wettability alteration and blockage. The natural mechanism is not fully comprehended until now due to impossibility to carry out actual field experiments. In this work, different flow dynamic test scenarios are organized to perform on sandstone as well as carbonate rocks to practically explore process of asphaltene deposition. Ordinary optimized methods are not applicable to asphaltene deposition due to its dependency on the involved parameters and complexity of process. The permeability impairment data is monitored through analysis of recorded pressures during the test experiments. Then, a new adaptive neuro-fuzzy inference system is developed to predict asphaltene deposition in terms of permeability (K/K0) and pressure drop (DP), considering pore volume injection (PVI) and time data as input variables. Accordingly, two adaptive neuro-fuzzy models are sequentially developed in a nonlinear affine-type configuration to investigate the effect of multiple variables and parameters on asphaltene deposition on the basis of the most recent input-output data. A series of test studies has been conducted to demonstrate the efficient capabilities of the proposed algorithm to automatically predict asphaltene deposition for different prediction horizons using the online affine-type identified models. Eventually, acceptable agreement between experimental and estimated permeability and pressure drop is investigated to demonstrate superiority of the proposed approach to monitor future asphaltene status that will be useful to prediction of field production under natural depletion process.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Alcohols, Alkanes, Ammonia, Benzene, Carbon dioxide, Critical point, Equation of state, Hydrogen fluoride, Hydrogen sulphide, Phase behaviour, Renormalisation-group, SAFT-VR, Second derivative properties, and Water

In earlier work, a methodology to couple SAFT-VR with an RG treatment (SAFT-VR + RG) for square-well chain and associating fluids was presented [E. Forte, F. Llovell, L.F. Vega, J.P.M. Trusler, A. Galindo, J. Chem. Phys. 134 (15) (2011) 154102]. The approach is based on a recursive procedure which begins with an initial free energy incorporating only contributions from short-wavelength density fluctuations, which are treated locally. The contribution from long-wavelength fluctuations is incorporated through the iterative procedure based on attractive interactions that incorporate the structure of the fluid following the ideas of perturbation theories and using a mapping that allows integration of the radial distribution function. The resulting SAFT-VR + RG theory provides an equation of state based on the classical SAFT-VR equation and yields the correct critical behaviour without the need for additional adjustable parameters. In this work, the application of this equation to real fluids is presented. The ability of the methodology to reproduce the phase behaviour close to and far from criticality solely through the standard SAFT-VR molecular parameters is demonstrated here. Molecular model parameters for a range of fluids, both non-associating and associating are presented, including the homologous series of n-alkanes, benzene, carbon dioxide, water, light alcohols, ammonia, hydrogen fluoride and hydrogen sulphide. These were determined by comparison with experimental data for vapour pressure and saturated liquid density. Furthermore, the models presented are used to predict second derivative properties for these compounds. Deviations compared with the original SAFT-VR equation are discussed in order to assess further the improvements introduced by the coupled theory to predict these properties. The critical exponents α, β, γ and δ have also been obtained for a number of these fluids and found to be in good agreement with the universal values of the three-dimensional Ising model.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Aliphatic hydrocarbon, Aromatic hydrocarbon, Cyclic voltammetry, Dynamic light scattering, and Water-oil interface

The aggregate structures and adsorption of anionic surfactant on interfacial region between water-hexane and -heptane as aliphatic hydrocarbons and -toluene as an aromatic hydrocarbon have been investigated by surface tension and conductometry at different electrolyte concentrations at different temperatures. Cyclic voltammetry and dynamic light scattering measurements have been used in order to explore the effect of aromatic hydrocarbons on the size of micellar aggregates. Also, the effect of hydrocarbons on particle size has been investigated. The presence of alkanes decreases the surface tension of water and the amount of adsorption of surfactant at interface of water-alkane, The values of free energy of adsorption are more negative than free energy of micelle formation, so in the presence of alkanes, the free energy of adsorption is affected more. In all systems and independent of the light phase, critical micelle concentration increases with rise of temperature due to breaking of water structure. Also, the results indicate a decreased adsorption with increase of temperature as molecular motions increase. However, free energy of micelle formation becomes more positive with the addition of salt.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, 2,2,4-Trimethylpentane (isooctane), 2-Methoxy-2-methylbutane (tert-amyl methyl ether), Benzene, Correlation, Density, Excess molar volume, Peng-Robinson equation, Redlich-Kister equation, and Vibrating-tube densimeter

Densities of ternary liquid mixtures composed of benzene, 2-methoxy-2-methylbutane (i.e. tert-amyl methyl ether, TAME), and 2,2,4-trimethylpentane (i.e. isooctane, 2,2,4-TMP) are measured at three temperatures 298.15 K, 308.15 K, and 318.15 K at atmospheric pressure by a vibrating-tube densimeter as well as all its binary sub-systems. Excess molar volumes of the mixtures are calculated from the experimental densities and then correlated using the Redlich-Kister equation. The determination of its adjustable parameters is made by the method of least squares. For all studied systems, the positive deviations from ideal behavior are observed at all temperatures. The excess molar volume curves of binary systems differ in the shape and temperature dependence. The experimental binary data are compared with literature data and discussed. The ternary system mentioned above is measured newly. Moreover, the experimental excess molar volumes are compared to the calculation using Peng-Robinson equation with a corrected parameter. The novelty of this work is the prediction of ternary excess molar volumes from binary parameters in Peng-Robinson equation.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, COSMO, Furan, Hexan, Molecular simulation, Monte Carlo, Phase diagram, Prediction, SAFT, and Toluene

In this paper, new experimental vapour-liquid equilibrium data of the furan+n-hexane and furan + toluene binary systems are reported. The data are determined using the ebulliometric technique. The measured data are used to assess the predictions obtained with molecular simulation, a group contribution polar PC-SAFT model and the COSMO-RS and COSMO-SAC approaches. For this purpose, new force field parameters (needed in MC-simulation) are determined for furans by fitting a limited amount of saturation data. In GC-PPC-SAFT, most of the parameters were adopted from previous studies with exception of the polar moments (dipoles are taken from experimental data). The mixtures phase diagrams are predicted (without binary parameters) at atmospheric pressure using these newly determined parameters as well as those of hexane and toluene determined in earlier studies. The predicted results are consistent with the new experimental data. Nevertheless, for the furan + n-hexane binary system, it appears that a binary interaction parameter is necessary to correctly correlate the data and to satisfactory describe the literature excess enthalpy data.

General chemistry, physical chemistry, Chimie générale, chimie physique, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Equilibres de phases, Phase equilibria, Généralités, General, Alkanone, Aromatic, DISQUAC, Interactions, Kirkwood-Buff, and Orientational effects

Linear alkanone or cyclohexanone + aromatic hydrocarbon mixtures have been studied using DIS-QUAC and the Kirkwood-Buff formalism. The aromatic compounds considered are: benzene, toluene, 1,4-dimethylbenzene, 1,2,4-trimethylbenzene and ethylbenzene. Vapour-liquid equilibria (VLE), molar excess Gibbs energies, GEm, molar excess enthalpies, HEm, and isobaric molar excess heat capacities, CEpm, of the binary systems studied are well represented by DISQUAC. There is a good agreement between experimental HEm values of related ternary mixtures, and DISQUAC predictions obtained by means of binary interaction parameters only DISQUAC improves very meaningfully UNIFAC results on HEm, CEpm, properties which are closely related to the molecular structure of the mixture components. The enthalpy (HCO-Sint) of the ketone-aromatic hydrocarbon interactions has been evaluated. These interactions become weaker when the alkanone size increases in mixtures with a given aromatic hydrocarbon, or when the aliphatic surface of the alkylbenzene is increased in systems with a given ketone. Steric effects are more relevant in 1,4-dimethylbenzene mixtures than in those with ethylbenzene. The application of the Kirkwood-Buff formalism to mixtures including toluene or ethylbenzene shows that orientational effects, related to ketone-ketone interactions, exist in solutions with the shorter 2-alkanones. Such effects are weakened when the chain length of the 2-alkanone increases. The opposite behaviour is observed when increasing the aliphatic surface of the alkylbenzene in systems with a given 2-alkanone. The cyclohexanone + benzene mixture shows a structure close to random mixing.