Thermophysical properties of biodiesel and related systems: (Liquid + liquid) equilibrium data for soybean biodiesel

This work reports (liquid + liquid) equilibrium (LLE) data for the systems of interest in soybean biodiesel production. Numerical data for LLE were obtained for binary, ternary and quaternary systems comprising fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAEE) from soybean oil, water, glycerol, methanol, and ethanol at temperatures of (303.15, 318.15, and 333.15) K. Quantification of compounds in equilibrium in both phases was determined by analytical methods whereas solubility curves (binodal) were obtained by the cloud-point method. For all systems investigated, good alignments were obtained between phase compositions and the initial as well as overall compositions hence indicating low deviations from the mass balance. Experimental results were correlated using the UNIQUAC model with satisfactory agreement between experiment and theory.     

Thermophysical properties of biodiesel and related systems: (Liquid + liquid) equilibrium data for castor oil biodiesel

This work reports new liquid–liquid solubility values (binodal curves) as well as (liquid + liquid) equilibrium data for, ternary and quaternary systems containing fatty acid methyl esters (FAME) and fatty acid ethyl esters (FAEE) from castor oil, water, glycerol, methanol and anhydrous ethanol at T = (303.15, 318.15, and 333.15) K. Solubility curves (binodal) were also obtained by the cloud-point method for binary systems containing FAME, FAEE, water, or glycerol. All results obtained can be considered of good quality. The experimental values were correlated using the UNIQUAC model, whose results presented good performance and satisfactory fitting of equilibrium values.     

Thermophysical properties of biodiesel and related systems: Low-pressure vapour–liquid equilibrium of methyl/ethyl Jatropha curcas biodiesel

Biodiesel production from non-edible oils has been considered in recent years due to their economic, politics and environmental aspects. Vapour–liquid equilibrium data for the pseudo-binary and pseudo-ternary systems involving fatty acid methyl/ethyl esters from Jatropha curcas oil were determined over the pressure range from (6.7 to 66.7) kPa in an Othmer-type ebulliometer. All systems presented non-ideal behaviour and positive deviations from Raoult’s law. It was observed that the addition of up to 10 wt.% of alcohol (methanol or ethanol) promoted a significant decrease in the boiling point temperatures for the evaluated systems. The UNIQUAC model was used to correlate the experimental values, with good agreement between experiment and model results.     

Binodal curve measurements for (water + propionic acid + dichloromethane) ternary system by cloud point method

The binodal (solubility) curves and tie line data for ternary systems of (water + propionic acid + dichloromethane) at 91.3 kPa and T = (277.15, 284.15, and 294.15) K are reported. The binodal curve results were determined by cloud point measurements method. A simple titration method has been used for determining of the concentration of propionic acid in the both liquid phases at equilibrium. The results obtained were successfully correlated with the UNIQUAC activity coefficient model. The deviations between experimental and calculated compositions in both phases for the ternary system using this model are reported. The partition coefficients of propionic acid and the selectivity factor of dichloromethane for extracting of propionic acid from water were calculated and are reported. The phase diagrams for the ternary system studied including both the experimental and correlated tie lines are presented.     

(Liquid + liquid) equilibria of (water + butyric acid + esters) ternary systems

(Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for mixtures of {water (1) + butyric acid (2) + ethyl propionate or dimethyl phthalate or dibutyl phthalate (3)} at T = 298.15 K and (101.3 ± 0.7) kPa. The relative mutual solubility of the butyric acid is higher in the layers of esters than in the aqueous layer. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

(Liquid + liquid) equilibria of (water + butyric acid + dibasic esters) ternary systems

(Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for mixtures of {water (1) + butyric acid (2) + dimethyl succinate or dimethyl glutarate or dimethyl adipate (3)} at T = 298.15 K and p = (101.3 ± 0.7) kPa. The relative mutual solubility of the butyric acid is higher in the dibasic esters layers than in the aqueous layer. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

(Liquid + liquid) equilibria of (water + propionic acid + dibasic esters) ternary systems

(Liquid + liquid) equilibrium (LLE) data for the solubility curves and tie-line compositions were examined for mixtures of {water (1) + propionic acid (2) + dimethyl succinate or dimethyl glutarate or dimethyl adipate (3)} at T = 298.15 K and atmospheric pressure, (101.3 ± 0.7) kPa. The relative mutual solubility of the propionic acid is higher in the dibasic esters phases than in the aqueous phase. The reliability of the experimental tie-line data were confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC and modified UNIFAC methods. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

(Liquid + liquid) equilibria of (water + propionic acid + diethyl succinate or diethyl glutarate or diethyl adipate) ternary systems

(Liquid + liquid) equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for {water (1) + propionic acid (2) + diethyl succinate or diethyl glutarate or diethyl adipate (3)} at T = 298.15 K and 101.3 ± 0.7 kPa. The relative mutual solubility of the propionic acid is higher in the dibasic esters layers than in the aqueous layers. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems was predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

Isobaric (vapour + liquid) equilibria for N-formylmorpholine with ethylbenzene,n-butylbenzene,iso-propylbenzene and 1,2,4-trimethylbenzene at 101.33 kPa

The isobaric (vapour + liquid) equilibrium (VLE) of N-formylmorpholine with aromatics (ethylbenzene, n-butylbenzene, isopropylbenzene, 1,2,4-trimethylbenzene) at 101.33 kPa was investigated. The experimental VLE data for the four binary systems were tested and verified to be thermodynamically consistent by the Herington analysis method. At the same time, the non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models were used to correlate the experimental data with temperature-independent parameters. The average absolute deviations of the temperature correlated by NRTL model and UNIQUAC model for all the systems are below 0.62 K and the average absolute deviations for the vapour phase compositions are all below 0.083. In addition, the UNIFAC (Do) group contribution model was used to correlate and estimate the VLE data. The N-formylmorpholine was treated as a group (NFM). The group interaction parameters for CH₂-NFM, ACH-NFM and ACCH₂-NFM were regressed. The UNIFAC (Do) model can correlate the experimental data well. The group interaction parameters were used to estimate VLE data of the (o-xylene + N-formylmorpholine), (m-xylene + N-formylmorpholine) and (p-xylene + N-formylmorpholine) binary systems. The estimated data fit well with the literature data. The average absolute deviations of the temperature for N-formylmorpholine with (o-xylene, m-xylene, p-xylene) are 1.67 K, 1.77 K and 1.35 K, respectively, and the average absolute deviations for the vapour phase compositions of o-xylene, m-xylene and p-xylene are 0.0133, 0.0057 and 0.0059, respectively.     

Densities,viscosities, refractive indices,and surface tensions for binary and ternary mixtures of 2-propanol,tetrahydropyran, and 2,2,4-trimethylpentane

Densities, viscosities, refractive indices, and surface tensions of the ternary system (2-propanol + tetrahydropyran + 2,2,4-trimethylpentane) at T = 303.15 K and its constituent binary systems (2-propanol + tetrahydropyran, 2-propanol + 2,2,4-trimethylpentane, and tetrahydropyran + 2,2,4-trimethylpentane) at T = (293.15, 303.15, 313.15, and 323.15) K were measured at atmospheric pressure. Densities were determined using a vibrating-tube densimeter. Viscosities were measured with an automatic microviscometer based on the rolling-ball principle. Refractive indexes were measured using a digital Abbe-type refractometer. Surface tensions were determined by the Wilhelmy-plate method. From these data, excess molar volumes, deviations in viscosity, deviations in refractive index, and deviations in surface tension were calculated. The results for the binary and ternary systems were fitted to the Redlich–Kister equation and the variable-degree polynomials in terms of compositions, respectively. The experimental and calculated quantities are used to study the nature of mixing behaviour between mixture components.     

(Liquid + liquid) equilibria of (water + lactic acid + alcohol) ternary systems

(Liquid + liquid) equilibrium (LLE) measurements of the solubility (binodal) curves and tie-line end compositions were carried out for {water (1) + lactic acid (2) + octanol, or nonanol, or decanol (3)} at T = 298.15 K and 101.3 ± 0.7 kPa. The relative mutual solubility of lactic acid is higher in the water layers than in the organic layers. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE results for the ternary systems were predicted by UNIFAC method. Distribution coefficients and separation factors were evaluated for the immiscibility region.     

Temperature and composition dependence of the density and viscosity of binary mixtures of (hyperbranched polymer,B-U3000 + 1-alcohol,or ether)

Density and viscosity were determined for binary mixtures of {hyperbranched polymer, a fatty acid modified dendritic polymer Boltorn U3000 (B-U3000) + 1-alcohol (1-butanol, 1-hexanol, and 1-octanol)} at T = (298.15, 308.15, 318.15, 328.15, and 338.15) K and of {B-U3000 + tert-butyl-methylether (MTBE)} at T = (298.15, 308.15, and 318.15) K and ambient pressure. The temperature dependence of density and viscosity for these systems can be described by linear regression and by the Vogel–Fucher–Tammann equation, respectively. Excess volumes were discussed in a function of mass fractions. Viscosity deviations were calculated and correlated by the Redlich–Kister polynomial expansions using also the mass fractions. The polynomial correlations describe the variation of viscosity with composition. A qualitative discussion on these quantities in terms of molecular interactions is reported.     

(Liquid + liquid) equilibria of (sulfolane + benzene + n-hexane), (N-formylmorpholine + benzene + n-hexane), and (sulfolane + N-formylmorpholine + benzene + n-hexane) at temperatures ranging from (298.15 to 318.15) K: Experimental results and correlation

The experimental (liquid + liquid) equilibrium (LLE) properties for two ternary systems containing (N-formylmorpholine + benzene + n-hexane), (sulfolane + benzene + n-hexane) and a quaternary mixed solvent system (sulfolane + N-formylmorpholine + benzene + n-hexane) were measured at temperature ranging from (298.15 to 318.15) K and at an atmospheric pressure. The experimental distribution coefficients and selectivity factors are presented to evaluate the efficiency of the solvents for extraction of benzene from n-hexane. The LLE results obtained indicate that increasing temperature decreases selectivity for all solvents. The LLE results for the systems studied were used to obtain binary interaction parameters in the UNIQUAC model by minimizing the root mean square deviations (RMSD) between the experimental and calculated results. Using the interaction parameters obtained, the phase equilibria in the systems were calculated and plotted. The calculated compositions based on the UNIQUAC model were found to be in good agreement with the experimental values. The result of the RMSD obtained by comparing the calculated and experimental two-phase compositions is 0.0163 for (N-formylmorpholine + benzene + n-hexane) system and is 0.0120 for (sulfolane + benzene + n-hexane) system.     

Volumetric properties,viscosities and refractive indices of binary liquid mixtures of tetrafluoroborate-based ionic liquids with methanol at several temperatures

Densities, speeds of sound, viscosities and refractive indices of two binary systems 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF₄] + methanol and 1-ethyl-3-methylimidazolium tetrafluoroborate [emim][BF₄] + methanol, as well as of all pure components, have been measured covering the whole range of compositions at T = (278.15 to 318.15) K and p = 101 kPa. From this data, excess molar volumes, excess isentropic compressibilities, viscosity deviations and refractive index deviations were calculated and fitted to extended versions of the Redlich–Kister equation. Estimated coefficients of these equations taking into account the dependence on composition and temperature simultaneously were also presented.     

(Liquid + liquid) equilibrium data for the ternary systems (cycloalkane + ethylbenzene + 1-ethyl-3-methylimidazolim ethylsulfate) at T = 298.15 K and atmospheric pressure

In this paper, (liquid + liquid) equilibrium (LLE) data for the ternary systems (cyclohexane, or cyclooctane, or methylcyclohexane + ethylbenzene + 1-ethyl-3-methylimidazolium ethylsulfate) have been determined experimentally at T = 298.15 K and atmospheric pressure. The solubility curves and the tie-line compositions of the conjugate phases were obtained by means of density. The degree of consistency of the tie-lines was tested using the Othmer–Tobias equation, and the Non-Random Two-Liquid (NRTL) and the Universal Quasi-Chemical (UNIQUAC) models were used to correlate the phase equilibrium in the systems. Selectivity and solute distribution ratio were evaluated for the immiscible region.     

(Liquid + liquid) equilibria for mixtures of (ethylene glycol + benzene + cyclohexane) at temperatures (298.15, 308.15, and 318.15) K

Experimental (liquid + liquid) equilibrium (LLE) data for a ternary system containing (ethylene glycol + benzene + cyclohexane) were determined at temperatures (298.15, 308.15, and 318.15) K and at atmospheric pressure. The experimental distribution coefficients and selectivity factors are presented to evaluate the efficiency of the solvent for extraction of benzene from cyclohexane. The effect of temperature in extraction of benzene from the (benzene + cyclohexane) mixture indicated that at lower temperatures the selectivity (S) is higher, but the distribution coefficient (K) is rather lower. The LLE results for the system studied were used to obtain binary interaction parameters in the UNIQUAC and NRTL models by minimizing the root mean square deviations (RMSD) between the experimental results and calculated results. Using the interaction parameters obtained, the phase equilibria in the systems were calculated and plotted. The NRTL model fits the (liquid + liquid) equilibrium data of the mixture studied slightly better. The root mean square deviations (RMSDs) obtained comparing calculated and experimental two-phase compositions are 0.92% for the NRTL model and 0.95% for the UNIQUAC model.     

Phase separation in aqueous two-phase systems containing poly(ethylene glycol) and magnesium sulphate at different temperatures

New experimental (liquid + liquid) equilibrium data have been determined for aqueous systems containing poly(ethylene glycol) of nominal molar mass 10,000 and magnesium sulphate at T = (295.15, 301.15, 305.15, and 311.15) K. The effect of temperature on the liquid compositions of coexisting phases is discussed. The experimental (liquid + liquid) equilibrium data of the systems were correlated by non-random two-liquid (NRTL) activity coefficient model. The interaction parameters of the NRTL activity coefficient model are obtained and reported. The calculated root mean square deviations (RMSD) showed that NRTL activity coefficient model can be used satisfactorily to correlate the (liquid + liquid) equilibrium data in aqueous solution of the {poly(ethylene glycol) + magnesium sulphate} system.     

Excess molar enthalpies of binary systems containing 2-octanone,hexanoic acid,or octanoic acid at T = 298.15 K

An isothermal titration calorimeter was used to measure the excess molar enthalpies (H^E) of six binary systems at T = 298.15 K under atmospheric pressure. The systems investigated include (1-hexanol + 2-octanone), (1-octanol + 2-octanone), (1-hexanol + octanoic acid), (1-hexanol + hexanoic acid), {N,N-dimethylformamide (DMF) + hexanoic acid}, and {dimethyl sulfoxide (DMSO) + hexanoic acid}. The values of excess molar enthalpies are all positive except for the DMSO- and the DMF-containing systems. In the 1-hexanol with hexanoic acid or octanoic acid systems, the maximum values of H^E are located around the mole fraction of 0.4 of 1-hexanol, but the H^E vary nearly symmetrically with composition for other four systems. In addition to the modified Redlich–Kister and the NRTL models, the Peng–Robinson (PR) and the Patel–Teja (PT) equations of state were used to correlate the excess molar enthalpy data. The modified Redlich–Kister equation correlates the H^E data to within about experimental uncertainty. The calculated results from the PR and the PT are comparable. It is indicated that the overall average absolute relative deviations (AARD) of the excess enthalpy calculations are reduced from 18.8% and 18.8% to 6.6% and 7.0%, respectively, as the second adjustable binary interaction parameter, k_bij, is added in the PR and the PT equations. Also, the NRTL model correlates the H^E data to an overall AARD of 10.8% by using two adjustable model parameters.     

Densities and derived thermodynamic properties of binary (alkanol + boldine) mixtures in the compressed liquid region

In this work, densities of two binary systems of {alkanol (ethanol and 1-propanol) + boldine} are measured at temperatures from (313 to 363) K and pressures up to 20 MPa using an Anton Paar vibrating tube densimeter. Each (alkanol + boldine) system was prepared at five diluted compositions with respect to the alkaloid. These are (x₂ = 0.0012, 0.0074, 0.0136, 0.0196, 0.0267) and (x₂ = 0.0018, 0.0046, 0.0077, 0.0112, 0.0142) mixed in ethanol and 1-propanol, respectively. Experimental densities are correlated using an empirical 6-parameter equation with deviations within 0.04%. Extrapolated densities at atmospheric pressure agree with the literature data. Isobaric expansivity, isothermal compressibility, thermal pressure coefficient, and internal pressure have been calculated.     

(Liquid + liquid) equilibrium of {water + phenol + (1-butanol,or 2-butanol,or tert-butanol)} systems

(Liquid + liquid) equilibrium (LLE) and binodal curve data were determined for the systems (water + phenol + tert-butanol) at T = 298.15 K, (water + phenol + 2-butanol) and (water + phenol + 1-butanol) at T = 298.15 K and T = 313.15 K by the combined techniques of densimetry and refractometry. Type I curve (for tert-butanol) and Type II curves (for 1- and 2-butanol) were found. The data were correlated with the NRTL model and the parameters estimated present root mean square deviations below 2% for the system with tert-butanol and lower than 0.8% for the other systems.