Pure Component Data Research Articles

Interfacial properties of selected binary mixtures containing n-alkanes

We report the correlation and prediction of the subcritical vapour–liquid interfacial properties of three asymmetric binary mixtures composed of long n-alkanes in equilibria with a smaller solvent: hexane + decane, carbon dioxide + decane, and ethane + eicosane. The interfacial region is described by the complementary use of the Square Gradient Theory (SGT) and molecular dynamics (MD) simulations that allow the prediction of both the macroscopic and molecular level properties of the binary fluid mixtures. Calculations with SGT rely on the description of the vapour–liquid equilibria (VLE) by means of the Statistical Associated Fluid Theory (SAFT) equation of state. MD simulations are performed in the canonical ensemble using united-atom potentials to probe coexisting phases and the accompanying interface simultaneously. In addition to the phase equilibrium compositions and interfacial tensions, other interfacial properties, such as concentration profiles along the interfacial region, surface activities, and relative Gibbs adsorption isotherms at the interfaces have been obtained from a combination of SGT and MD. The entropy and surface enthalpy change of surface formation are also calculated for the case of ethane + eicosane mixture, where we report three different isothermal conditions. While pure component data are used to fit model parameters, mixture results are predictions. When possible, results are compared to available experimental data and quantitative agreement is observed throughout. The particularly high excess adsorption in the interface of the smaller solvents, CO 2 and ethane, is noted.

First-Principles Predictions of Vapor−Liquid Equilibria for Pure and Mixture Fluids from the Combined Use of Cubic Equations of State and Solvation Calculations

A novel approach combining first-principles solvation calculations and cubic equations of state is proposed for the prediction of phase equilibria of both pure and mixture fluids. The temperature and composition dependence of the energy parameter, a(T,x), in the EOS is determined from the attractive contribution to the solvation free energy. The volume parameter, b(x), is estimated to be the mole-fraction-weighted average volume of the molecular solvation cavity. This approach does not require the input of any experimental data (e.g., critical properties or acentric factor) for pure components and does not presume any composition dependence of the energy parameter. The Peng−Robinson EOS combined with a solvation model based on COSMO-SAC calculations, denoted as PR+COSMOSAC, is used to illustrate the applicability of this approach. It is found that the relative error from PR+COSMOSAC is 48% in vapor pressure, 21% in liquid density at the normal boiling point, 10% in critical pressure, 4% in critical temper...

Recommended NRTL Model Parameters by Simultaneous Correlation of VLE, Infinite Dilution Activity Coefficients and Excess Enthalpy Data

This paper deals with the determination of recommended temperature dependent NRTL parameters by simultaneous correlation of VLE-, γ ∞-, and hE data from the Dortmund Data Bank (DDB) using an interactive program package. Correlation results for selected mixtures are discussed in detail. The program package RECVAL is directly interfaced to the Dortmund Data Bank, makes extensive use of graphics for data representation and may be extended for the correlation and prediction of further mixture or pure component data. To ensure rapid conversion in case of a large amount of data, simultaneous convergence of the outer parameter fitting loop and the inner phase equilibrium iterations is employed. Recommended temperature dependent NRTL parameters have been determined for 133 binary systems. These parameters have been obtained by a simultaneous fit to VLE-, γ ∞-, and hE-data stored in DDB.

The Soave, Twu and Boston–Mathias alpha functions in cubic equations of state: Part I. Theoretical analysis of their variations according to temperature

A theoretical analysis of the strengths and weaknesses of the Soave, Twu and Boston–Mathias attractive terms was performed with the Redlich–Kwong EoS. Special attention was paid to the variations of the alpha functions and their first and second derivatives with respect to temperature. Contrary to the Soave function, abnormal behaviors of the derived Twu and Boston–Mathias functions were evidenced in the temperature range commonly covered by industrial applications. The unsuccessful variations of the derived alpha functions observed with these two last models strengthen the interest of the Soave equation for the modeling of derived thermodynamic properties. The accuracy of pure component data modeling by means of the cubic equation of state is discussed in a second part.

A generalisation of the SAFT- [formula omitted] group contribution method for groups comprising multiple spherical segments

A new group contribution (GC) approach based on the statistical associating fluid theory (SAFT- γ ) has recently been proposed [A. Lymperiadis, C. S. Adjiman, A. Galindo, G. Jackson, J. Chem. Phys. 127 (2007) 234903]. In this continuum equation of state GC approach, the molecules are formed from fused heteronuclear spherical segments each of which represents a distinct chemical functional group. The different segments are characterised by size and attractive energy (well-depth and range) parameters, and a shape-factor parameter which describes the contribution that each segment makes to the overall molecular properties. In addition a number of bonding sites are included on a given segment to deal with association interactions where appropriate; the association between sites introduces two additional energy and range parameters. Our heteronuclear molecular models are thus fundamentally different from the homonuclear models employed with other GC versions of SAFT in which the GC concept is introduced to obtain average molecular parameters. In the current work, we generalise the SAFT- γ equation of state to treat chemical groups which are represented by more than a single spherical segment. This allows for a good description of the properties of large functional groups such as carboxyl and carbonyl groups. The original parameter table for the CH 3, CH 2, CH 3CH, ACH (where AC denotes an aromatic carbon), ACCH 2, CH 2 , CH and OH groups is now extended to include the C O, COOH, and NH 2 groups by examining the vapour–liquid equilibria (VLE) of pure 2-ketones, carboxylic acids, and primary amines. It is demonstrated that the proposed theory provides an excellent description of the vapour–liquid equilibria for all of the chemical families considered, and that the new group parameters can be used in a predictive fashion to model the phase behaviour of larger compounds not included in the estimation database. One of the principal advantages of the SAFT- γ formalism is that the binary interaction parameters between groups of different types can be estimated from pure component data alone. This is particularly useful in describing the properties of fluid mixtures. The adequacy of the method in predicting the VLE is assessed for selected binary mixtures of associating and non-associating compounds. A strict test of any GC method is its ability to capture both vapour–liquid and liquid–liquid equilibria (LLE) with the same set of group parameters. It is very gratifying to find that with SAFT- γ one is able to reproduce the VLE and LLE behaviour for several mixtures simultaneously, for example, n- hexane + propanone , and n- pentane + polyethylene .

Microphase Separation and Morphology of the Real Polymer System by Dynamic Density Functional Theory, Based on the Equation of State

Microphase separation and morphology evolution of polystyrene and polybutadiene blends are quantitatively studied by the dynamic density functional theory that is based on the equation of state (EOS-based DDFT). The structure parameters of coarse-grained beads are regressed from the experimental pressure−volume−temperature data of pure components. The comparisons between simulated and experimental results are presented as illustrations. Notably, in the region near the critical composition, the deviation of the order−disorder transition temperature between simulation and experiment is <10 °C. Considering the fact that EOS-based DDFT is a unique simulation method that can predict the morphologies of blends in the different temperatures and compositions and match the simulated and experimental results in the same time, which is beyond the capabilities of the phase equilibrium theory and other simulation methods, such a deviation is obvious, but definitely acceptable. The factors that affect the accuracy of t...

Adsorption Equilibrium and Kinetics of Microorganisms on Single-Wall Carbon Nanotubes

Adsorption equilibrium and kinetics of pure and mixed cultures of Escherichia coli and Staphylococcus aureus on single-walled carbon nanotubes (CNT) aggregates were studied in an effort to develop CNT-based biosensors for quick detection of these bacteria in water. Batch experiments were carried out to measure the adsorption kinetics and equilibrium of pure and mixed culture of E. coli and S. aureus on the CNT aggregates at ambient temperature and various culture concentrations. The CNT aggregates can adsorb significant amounts of E. coli and S. aureus bacteria with different size and shape characteristics. The smaller size S. aureus has a five to ten times faster diffusion rate than E. coli and about 100 times higher adsorption affinity with the carbon nanotube aggregates. Freundlich adsorption model correlates well both the pure component and mixture adsorption equilibrium data. It is quite possible the CNT aggregates have separate adsorption sites for both E. coli and S. aureus. The combined high adsorption affinity and fast adsorption kinetics for S. aureus suggest that even unmodified single-wall carbon nanotubes can selectively differentiate S. aureus and E. coli in water. Transmission electron microscopic analysis qualitatively confirmed the adsorption results and provides direct visualization of the adsorbed bacteria on carbon nanotube aggregates. Both bacteria form biofilms on carbon nanotube aggregates and have a strong tendency to connect with each other rather than with the carbon surface.

Segregation effects in adsorption of CO 2-containing mixtures and their consequences for separation selectivities in cage-type zeolites

For separation of CO 2 from gaseous mixtures with CH 4, N 2, or Ar, cage-type zeolites such as DDR, CHA, LTA, and ERI are of practical interest. These zeolites consist of cages separated by narrow windows and the selectivity of separation of CO 2 is dictated by both adsorption and diffusion characteristics. For adsorption of CO 2/CH 4 mixtures, Grand Canonical Monte Carlo (GCMC) simulations show that the window regions of cage-type zeolites have a significantly higher proportion of CO 2 than within the cages. Due to the segregated nature of mixture adsorption, the ideal adsorbed solution theory is unable to predict the mixture loadings accurately. For adsorption of CO 2/N 2, CO 2/Ar, and N 2/CH 4 segregation effects are also present but their impact is far less severe than for CO 2/CH 4 mixtures. For CO 2-bearing mixtures, the preponderance of CO 2 in the window regions has important consequences for mixture diffusion. Molecular dynamics (MD) simulations for self-diffusion in binary mixtures demonstrate that the CO 2 slows down the partner molecules far more than anticipated by the Maxwell–Stefan diffusion theory using pure component data inputs. The GCMC and MD simulation results also lead to the conclusion that DDR and CHA yield the highest permeation selectivities for membrane-based separation of CO 2/CH 4, CO 2/N 2, and CO 2/Ar mixtures. For N 2/CH 4 separation, DDR and ERI are the best choices.

Application of perturbed chain equation-of-state to solid–liquid equilibria: II. Binary mixtures

A perturbed chain equation-of-state was extended to the solid–fluid equilibria (SFE) of a binary mixture of chain molecules. A volume fraction-based mixing rule was applied to combine pure component segment size, chain length, and interaction energy parameters to form parameters that characterize the binary fluid–solid system. The solid–fluid equilibria (SFE) of n-alkane mixtures were correlated well with the model using only minor reliance on one binary interaction parameter. Values of the binary parameter correlated smoothly with difference in carbon number of the mixture components demonstrating potential of the model to be able to predict multi-component SFE from pure component data alone.

New Equation of State for Polymer Solutions Based on the Statistical Associating Fluid Theory (SAFT)−Dimer Equation for Hard-Chain Molecules

The dimer-chain term proposed by Ghonasgi and Chapman [J. Chem. Phys. 1994, 100, 6633−6639], which accounts for the chain connectivity, is used in conjunction with the perturbed-chain dispersion term proposed by Gross and Sadowski [Ind. Eng. Chem. Res. 2001, 40, 1244−1260] to form a new equation of state (EOS) for polyatomic fluids. The new EOS is applied to the homologous series of n-alkanes, mixtures of long- and short-chain alkanes, and polymers. The predictive and extrapolative capabilities of the model are demonstrated through comparisons with experimental data for pure components and mixtures. The new EOS provides an accurate description of liquid densities over the entire range of temperature, including the critical region. The predictions for mixtures of long- and short-chain alkanes are in excellent agreement with experimental data without using a binary interaction parameter. The description of the phase behavior of polymer solutions is improved, in comparison to perturbed-chain−statistical associating fluid theory (PC−SAFT) predictions, especially at high polymer concentrations.

Fundamental PVT Calculations for Associated and Gas/Condensate Natural-Gas Systems

SummaryProblems with existing procedures used to estimate gas pressure/volume/temperature (PVT) properties are identified. The situation is reviewed, and methods are proposed to alleviate these problems. Natural gases are derived from two basic sources: associated gas, which is liberated from oil, and gas condensates, where hydrocarbon liquid, if present, is vaporized in the gas phase. The two gases are fundamentally different in that a high-gravity associated gas is typically rich in ethane through pentane, while gas condensates are rich in heptanes-plus. Additionally, either type of gas may contain nonhydrocarbon impurities such as hydrogen sulfide, carbon dioxide, and nitrogen. Failure to distinguish properly between the two types of gases can result in calculation errors in excess of those allowable for technical work. Sutton (1985) investigated high-gravity gas/condensate gases and developed methods for estimating pseudocritical properties that resulted in more-accurate Z factors. The method is suitable for all light natural gases and the heavier gas/condensate gases. It should not be used for high-gravity hydrocarbon gases that do not contain a significant heptanes-plus component. The original Sutton database of gas/condensate PVT properties has been expanded to 2,264 gas compositions with more than 10,000 gas-compressibility-factor measurements. A database of associated-gas compositions containing more than 3,200 compositions has been created to evaluate suitable methods for estimating PVT properties for this category of gas. Pure-component data for methane (CH4), methane-propane, methane-n-butane, methane-n-decane, and methane-propane-n-decane have been compiled to determine the suitability of the derived methods. The Wichert (1970) database of sour-gas-compressibility factors has been supplemented with additional field and pure-component data to investigate suitable adjustments to pseudocritical properties that ensure accurate estimates of compressibility factors. Mathematical representations of compressibility-factor charts commonly used by the engineering community and methods used by the geophysics community are investigated. Generally, these representations/methods are robust and have been found suitable for ranges beyond those recommended originally. Natural-gas viscosity, typically estimated through correlation, has been found to be inadequate for high-gravity gas condensates, requiring revised procedures for accurate calculations.

Weighted-Power-Mean Mixture Model: Application to Multicomponent Liquid Viscosity

A multicomponent mixture may be viewed conceptually as a hypothetical collection of fluid clusters. In this context a mixture model is defined by prescriptions for (a) estimating fluid cluster properties and (b) combining them to yield an overall mixture property. A particularly flexible form is obtained using composition-weighted power means with the weighting based on global mole fractions. It predicts multicomponent properties from knowledge of pure component and binary mixture data. The classic quadratic Scheffé rational polynomials and the Wilson models are special cases. The model also generates a cubic Scheffé form for which ternary and higher coefficients can be expressed in terms of binary interactions. The binary-correlative and multicomponent-predictive capabilities of the model were evaluated for isothermal liquid viscosity data. A revised empirical mixing rule for liquid viscosity is proposed for systems where the constituent binaries show either convex or concave composition dependence.

Modeling of critical lines and regions for binary and ternary mixtures using non-cubic and cubic equations of state

In this work, two non-cubic equations of state, Perturbed Chain Statistical Association Fluid Theory (PC-SAFT) and Simplified Perturbed Hard Chain Theory (SPHCT) were used to predict critical lines and regions for several binary and ternary systems, by fitting one binary interaction parameter ( κ ij ) for each binary system. Results were compared with experimental critical data, which included inorganic gases, hydrocarbons (light and heavy paraffins, non-saturated olefins and aromatics), alcohols, carbon monoxide and carbon dioxide. These experimental data covered wide ranges of temperatures and pressures which are commonly used in industry. For comparison, the data were also modeled using two cubic equations of state: the well-known Peng–Robinson equation (PR) and the Patel–Teja–Valderrama equation (PTV). PC-SAFT and SPHCT pure-component parameters were obtained by regression, adjusting pure-component data such as vapor pressure and saturated liquid molar volume (taken from DIPPR 1.2.0). Excellent results were obtained with the PC-SAFT EoS, while the SPHCT, PR and PTV EoS did not have a good performance. The Heidemann and Khalil algorithm, with two nested single-variable iteration loops (an internal loop for volume and an external loop for temperature), was used for locating a single liquid–liquid or vapor–liquid critical point.

Monte Carlo Simulation of Carboxylic Acid Phase Equilibria

Configurational-bias Monte Carlo simulations were carried out in the Gibbs ensemble to generate phase equilibrium data for several carboxylic acids. Pure component coexistence densities and saturated vapor pressures were determined for acetic acid, propanoic acid, 2-methylpropanoic acid, and pentanoic acid, and binary vapor-liquid equilibrium (VLE) data for the propanoic acid + pentanoic acid and 2-methylpropanoic acid + pentanoic acid systems. The TraPPE-UA force field was used, as it has recently been extended to include parameters for carboxylic acids. To simulate the branched compound 2-methylpropanoic acid, certain minor assumptions were necessary regarding angle and torsion terms involving the -CH- pseudo-atom, since parameters for these terms do not exist in the TraPPE-UA force field. The pure component data showed good agreement with the available experimental data, particularly with regard to the saturated liquid densities (mean absolute errors were less than 1.1%). On average, the predicted critical temperature and density were within 1% of the experimental values. All of the binary simulations showed good agreement with the experimental x-y data. However, the TraPPE-UA force field predicts saturated vapor pressures of pure components that are larger than the experimental values, and consequently the P-x-y and T-x-y data of the binary systems also deviate from the measured data.

( p, v, T, x) Measurements of {(1 − x)H 2O + xC 2H 5OH} mixtures in the near-critical and supercritical regions

A constant-volume piezometer immersed in a precision thermostat was used to measure the ( p, v, T, x) relationship of three aqueous ethanol mixtures (0.2, 0.5, and 0.8) mole fraction of ethanol in the temperature range from (423.15 to 673.15) K, and at pressures between (0.9 and 51) MPa. This range includes the near-critical and supercritical regions. The measurements were performed in both one- and two-phase regions including the (vapour + liquid) coexistence curve. The total uncertainty of measurements of density, 0.15%, pressure, 0.05%, temperature, 15 mK, and composition, 0.05%. Isochoric and isothermal intersections with the phase boundary were performed to obtain the values of bubble and dew point pressures and densities. The values of the critical parameters ( T C, p C, and ρ C) were extracted from the measured ( p, v, T, x) relations in the critical region. Excess V m E , apparent ϕ V , and partial V ¯ 2 ∞ molar volumes were derived using the measured values of density for the mixtures and pure components data. For the water’s critical isotherm-isochore ( T = 647.1 K and 322.0 kg · m −3), the measurements were performed for very dilute mixtures to estimate accurately the values of the Krichevskii parameter. The value of the Krichevskii parameter was also calculated by using the critical-curves data for the mixture and vapour pressure data for the pure solvent (H 2O). The derived value of the Krichevskii parameter was used to analyze the critical behaviour of the thermodynamic and structural properties of the (H 2O + C 2H 5OH) mixture in terms of the principle of isomorphism of critical phenomena in binary mixtures. The values of the characteristic parameters ( K 1, K 2), temperatures ( τ 1, τ 2), and the characteristic density differences (Δ ρ 1, Δ ρ 2) were estimated for the (H 2O + C 2H 5OH) mixture by using the critical-curve data and the theory of isomorphism of the critical phenomena in binary mixtures.

Viscosities and Refractive Indices of Binary Mixtures of Dimethylsulphoxide with Some Aromatic Hydrocarbons at Different Temperatures: An Experimental and Theoretical Study

The viscosities, η, and refractive indices, n, of pure dimethylsulphoxide (DMSO), benzene, toluene, o-xylene, m-xylene, p-xylene and mesitylene, and those of their 54 binary mixtures, with DMSO as common component, covering the whole composition range have been measured at 298.15, 303.15, 308.15, 313.15, and 318.15 K. From the experimental data, the deviations in viscosity, Δη and deviations in molar refraction, ΔRm have been calculated. The variation of these parameters with composition and temperature of the mixtures have been discussed in terms of molecular interaction in these mixtures. The effect of the number and position of the methyl groups in these aromatic hydrocarbons on molecular interactions in these mixtures has also been discussed. The free energies, ΔG*, enthalpies, ΔH* and entropies, ΔS* of activation of viscous flow have also been obtained by using Eyring viscosity equation. The ΔH* values were found independent of temperature. The dependence of these thermodynamic parameters on composition of the mixtures has been discussed. Further, the viscosities and refractive indices of these binary mixtures were calculated theoretically from pure component data by using various empirical and semi-empirical relations and the results were compared with the experimental findings.

Adsorption Equilibria of Butan-1-ol, Toluene and Water Vapour onto Sorbonorit 4 Activated Carbon and the Co-Adsorption of Organic Compounds and Water Vapour onto SKT Activated Carbon

The results of both experimental and theoretical investigations are presented. The results of experimental investigations of adsorption equilibria for the pure components butan-1-ol, toluene and water vapour onto Sorbonorit 4 activated carbon are first reported, with measurements having been undertaken using a dynamic gravimetric method. The results for butan-1-ol and toluene were correlated using the Langmuir, Freundlich, Redlich–Peterson, Toth and Dubinin–Astakhov models, while the results for water vapour were correlated using the equations of Dubinin and Serpinsky and of Barton and Barton and co-workers. A simple model enabling the prediction of the adsorption equilibria of butan-1-ol/water vapour and toluene/water vapour mixtures on SKT activated carbon is then presented. Such predictions were made on the basis of data for the pure components, with the equilibrium data for both pure components and mixtures being taken from the literature. The model, which is simple to simulate and verify using experimental data, is based on the Polanyi theory and the Dubinin–Astakhov isotherm equation. With this model, fairly good agreement was observed between predicted and experimental binary mixture adsorption data for the systems examined.

Modeling the thermodynamic behavior of poly(lactide-co-glycolide) + supercritical fluid mixtures with equations of state

In this work, the thermodynamic behavior of binary systems composed by one commercial biodegradable copolymer [poly( d, l-lactide-co-glycolide)] and supercritical fluids, SCF, (dimethyl ether, carbon dioxide, chlorodifluoromethane and trifluoromethane) was studied. The perturbed chain-SAFT (PC-SAFT) and the Sanchez–Lacombe (SL) non-cubic equations of state (EoS) were used to model the fluid–liquid equilibrium (FLE) for these binary systems, by fitting one temperature-dependent binary interaction parameter. For comparison, the same data were also modeled by using the traditional Peng–Robinson (PR) cubic EoS. The three PC-SAFT and SL pure-component parameters and two PR pure-component parameters were regressed by fitting pure-component data (liquid pressure–volume–temperature, PVT, data for copolymer and saturated liquid vapor pressure and molar volume for SCF). Liquid PVT data of PLAG copolymers were estimated by using a group contribution method, taken from literature. The estimation of pure-component and binary interaction parameters was performed by using the modified maximum likelihood method with an objective function that includes the cloud point pressure. An excellent agreement was obtained with the PC-SAFT EoS, while the performance of the SL and PR EoS were less satisfactory.

Chemometric model for simultaneous spectrophotometric estimation of phenobarbitone and phenytoin sodium in tablets using back-propagation neural network

A chemometric model for the simultaneous estimation of phenobarbitone and phenytoin sodium anticonvulsant tablets using the back-propagation neural network calibration has been presented. The use of calibration datasets constructed from the spectral data of pure components is proposed. The calibration sets were designed such that the concentrations were orthogonal and span the possible mixture space fairly evenly. Spectra of phenobarbitone and phenytoin sodium were recorded at several concentrations within their linear range and used to compute the calibration mixture between wavelengths 220 and 260 nm at an interval of 1 nm. The back-propagation neural network model was optimized using three different sets of calibration and monitoring data for the number of hidden sigmoid neurons. The calibration model was thoroughly evaluated at several concentration levels using spectra obtained for 95 synthetic binary mixtures prepared using orthogonal designs. The optimized model showed sufficient robustness even when the calibration sets were constructed from different sets of pure spectra of components. Although the components showed complete spectral overlap, the model could accurately estimate the drugs, with satisfactory precision and accuracy, in tablet dosage with no interference from excipients, as indicated by the recovery study results.

Modeling the phase behavior of commercial biodegradable polymers and copolymer in supercritical fluids

Biodegradable polymers have received much attention as materials for reducing environmental problems caused by conventional plastic wastes. In this work, the thermodynamic behavior of binary and ternary systems composed by commercial biodegradable polymers and high-pressure fluids [poly( d, l-lactide) + dimethyl ether, poly( d, l-lactide) + carbon dioxide, poly( d, l-lactide) + chlorodifluoromethane, poly( d, l-lactide) + difluoromethane, poly( d, l-lactide) + trifluoromethane, poly( d, l-lactide) + 1,1,1,2-tetrafluoroethane, poly(butylene succinate) + carbon dioxide and poly( d, l-lactide) + dimethyl ether + carbon dioxide] and binary systems formed by commercial biodegradable copolymers and supercritical fluids [poly(butylene succinate-co-butylene adipate) + carbon dioxide] were studied. The Perturbed Chain-SAFT (PC-SAFT) and the Sanchez–Lacombe (SL) non-cubic EoS were used to model the liquid–fluid equilibrium (LFE) for these binary systems, by fitting one temperature-dependent binary interaction parameter. For comparison, the same data were also modeled by using the traditional Peng–Robinson (PR) cubic EoS. The three pure-component parameters of PC-SAFT and SL EoS and two pure-component of PR EoS were regressed by fitting pure-component data (liquid pressure–volume–temperature data for polymers and copolymer and vapor pressure and saturated liquid molar volume for fluids). The estimation of pure-component and binary interaction parameters was performed by using the modified maximum likelihood method with an objective function that includes the cloud point pressure. An excellent agreement was obtained with the PC-SAFT EoS, while the performance of the SL and PR EoS was less satisfactory.