(Solid + liquid) phase equilibria of binary mixtures containing N-methyl-2-pyrrolidinone and ethers at atmospheric pressure

Solid–liquid equilibria (SLE), have been measured from 270 K to the boiling temperature of the solvent for 10 binary mixtures of N-methyl-2-pyrrolidinone, with ethers (dipropyl ether, dibutyl ether, dipentyl ether, methyl 1,1-dimethylethyl ether, methyl 1,1-dimethylpropyl ether, ethyl 1,1-dimethylpropyl ether, 1,4-dioxane, tetrahydrofuran, tetrahydropyran, 18-crown-6) using a dynamic method. The solubility of N-methyl-2-pyrrolidinone in ethers is lower than in alcohols and generally decreases with an increase of the number of carbon atoms of ether chain. The highest intermolecular solute–solvent interaction is observed for the cyclic ethers and for methyl 1,1-dimethylethyl ether.Experimental solubility results are compared with values calculated by means of the Wilson, UNIQUAC ASM and two NRTL equations utilizing parameters derived from SLE results. The existence of a solid–solid first-order phase transition in 18-crown-6 ether has been taken into consideration in the calculations. The correlation of the solubility data has been obtained with the average root-mean-square deviation of temperature σ_T = 0.9 K with UNIQUAC ASM and two NRTL equations and 0.6 K with the Wilson equation.     

(Solid + liquid) equilibria of (nalkanes + ethyl 1,1-dimethylpropyl ether)

(Solid  +  liquid) equilibria (s.l.e.) have been measured atT >  280 K for (octadecane, or nonadecane, or eicosane, or heneicosane, or docosane, or tricosane, or tetracosane, or hexacosane, or heptacosane, or octacosane  +  ethyl 1,1-dimethylpropyl ether ETAE). The experimental results are compared with values calculated by means of the Wilson, UNIQUAC and NRTL equations utilizing parameters derived from the experimental s.l.e. The existence of a (solid  +  solid) first-order phase transition in hydrocarbons has been taken into consideration in the solubility calculations. The solubility of hydrocarbons in branched-chain ethers is lower than that in n -alkanes but higher than that in cycloalkanes, branched alkanes, 1-alcohols andtert -alcohols. The best correlation of the solubility data has been obtained by the NRTL equation where the average root-mean-square deviation of the solubility temperatures is 0.36 K.     

(Solid + liquid) phase equilibria of binary mixtures containing N-methyl-2-pyrrolidinone and alcohol at atmospheric pressure

The (solid + liquid) equilibria of {N-methyl-2-pyrrolidinone + 1-propanol, or 2-propanol, or 1-butanol, or 2-methyl-1-propanol, or 2-methyl-2-propanol, or 1-pentanol} has been measured by a dynamic method. The experimental results have been correlated using the Wilson, UNIQUAC ASM and two modified NRTL equations. The root-mean-square deviations of the solubility temperatures for all the calculated values vary from (0.5 to 2.1) K and depend on the particular equation used. The specific interaction between the carbonyl group of the NMP molecule and the alcohol has been discussed.     

Solid–liquid equilibria for systems containing 1-butyl-3-methylimidazolium chloride

The solubility of 1-butyl-3-methylimidazolium chloride [C₄mim][Cl] in alcohols {ethanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol, 1-dodecanol, 2-butanol, 2-methyl-2-propanol (tert-butanol)} has been measured by a dynamic method from 270 K to the melting point of the ionic liquid or to the boiling point of the solvent. The melting point, enthalpy of fusion, and the temperature of the glass phase transition were determined by differential scanning calorimetry.The solubility data were correlated by means of the Wilson, UNIQUAC ASM and modified NRTL1 equations utilizing parameters derived from the solid–liquid equilibrium data. The root-mean-square deviations of the solubility temperatures for all calculated data were higher than 0.9 K and depended on the particular equation used.     

Evaluation of the polysubstituted pyridinium ionic liquid [hmmpy][Ntf2] as a suitable solvent for desulfurization: Phase equilibria

Suitability of a pyridinium ionic liquid as a solvent in desulfurization has been analyzed. (Liquid + liquid) equilibria for ternary systems composed by 1-hexyl-3,5-dimethyl pyridinium {bis[trifluoromethylsulfonyl]imide, thiophene, and three hydrocarbons representative of fuel (n-heptane, 2,2,4 trimethylpentane, and toluene) have been determined at T = 298.15 K and atmospheric pressure. High solubility of thiophene in the ionic liquid and also of toluene have been found, being this solvent practically immiscible with 2,2,4 trimethylpentane and heptane. Equilibrium data of these systems have been well correlated with UNIQUAC equations finding the highest deviations for the ternary system involving toluene. NRTL model drove to worse results being considered as not suitable model to correlate the experimental results.     

Solubility of tridecanedioic acid in pure solvent systems: An experimental and computational study

Solubility has been extensively investigated by the phase equilibria approach at the mesoscale level, but its origin on the molecular and electronic levels is poorly understood. This study explored the solubility behaviour of crystalline solid in selected pure solvents with various functional groups by using both phase equilibria and molecular modelling methods. The model compound tridecanedioic acid (TDDA) solubility in methanol, ethanol, acetic acid, acetone, and ethyl acetate was determined from T = (283.15 to 323.15) K by a static method. It was found that almost all solutions studied exhibit non-ideal behaviour and deviate positively from Raoult’s law indicating the important role of homo-molecules interactions. Thermodynamic analyses of solution suggest that both enthalpy and entropy of solution govern the dissolution process. Computational studies on solubility behaviour were performed by using both density functional theory (DFT) calculations and molecular dynamic (MD) simulations. The results conclude that the (solute + solvent) interaction is not the only factor determining solubility, and (solvent + solvent) interaction also plays an important role. The simulated results are found to be qualitatively consistent with experimental values. Finally, solubility values were correlated by the empirically modified Apelblat equation and two local composition models of Wilson and NRTL.     

Solubility measurement and modelling of 1,8-dinitronaphthalene in nine organic solvents from T = (273.15 to 308.15) K and mixing properties of solutions

The solubility of 1,8-dinitronaphthalene in acetonitrile, methanol, ethanol, trichloromethane, isopropanol, acetone, toluene, ethyl acetate and butyl alcohol were obtained experimentally at temperatures ranging from (273.15 to 308.15) K under 0.1 MPa by using a gravimetric method. The solubility of 1,8-dinitronaphthalene in those solvents increases with an increase in temperature. The solubility values decrease according to the following order: acetone > (acetonitrile, ethyl acetate) > trichloromethane > toluene > methanol > ethanol > isopropanol > butyl alcohol. Three models, the modified Apelblat equation, Wilson and NRTL were used to correlate the solubility of 1,8-dinitronaphthalene in the solvents studied. The calculated solubility by the modified Apelblat equation provides better agreement than those evaluated by the other two models. The regressed results via the three models are all acceptable for the solubility of 1,8-dinitronaphthalene in the selected solvents. Furthermore, the mixing Gibbs energy, mixing enthalpy, and mixing entropy for per 1 mol of mixture of 1,8-dinitronaphthalene and solvents were calculated based on the Wilson model. The dissolution process of 1,8-dinitronaphthalene in the selected solvents is spontaneous and exothermic.     

Phase diagrams of binary systems containing n-alkanes,or cyclohexane,or 1-alkanols and 2,3-pentanedione at atmospheric and high pressure

Phase equilibria, for the binary systems {n-alkanes (tridecane, octadecane, or eicosane), or cyclohexane, or 1-alkanol (1-hexadecanol, or 1-octadecanol, or 1-eicosanol) + 2,3-pentanedione} have been determined using a cryometric dynamic method at atmospheric pressure. The influence of pressure on liquidus curve up to 800 MPa was determined for (tridecane, or cyclohexane + 2,3-pentanedione) systems. A thermostated apparatus for the measurements of transition pressures from the liquid to the solid state in two component isothermal solutions (pressometry) was used. The freezing and melting temperatures at a constant composition increase monotonously with pressure. The high-pressure experimental results obtained at isothermal conditions (p–x) were interpolated to well known T–x diagrams.Immiscibility in the liquid phase was observed only for the n-alkanes mixtures. The solubility decreases with an increase of the number of carbon atoms in the n-alkane, or 1-alkanol chain. The higher intermolecular solute–solvent interaction was observed for the 1-alkanols.Experimental solubility results are compared with values calculated by means of the NRTL equation (n-alkanes) and the NRTL and UNIQUAC ASM equations utilizing parameters derived from SLE and LLE results. The existence of a solid–solid first-order phase transition in tridecane, eicosane and 1-alkanols has been taken into consideration in the calculations. The correlation of the solubility data has been obtained with the average root-mean-square deviation of temperature σ < 1.0 K with both equations. The pressure–temperature–composition relation of the high-pressure (solid + liquid) phase equilibria, was satisfactorily presented by the polynomial.     

Heterogeneous catalytic ozonation process for removal of 4-chloro-2-nitrophenol from aqueous solutions

This research investigated the efficiency of nanosized ZnO in the catalytic ozonation of 4-chloro-2-nitrophenol and determined the effect of pH on heterogeneous catalytic ozonation. Use of ozone with ZnO catalyst leads to conversion of 98.7% of 4-chloro-2-nitrophenol during 5 min. In addition, it was found that in ZnO catalytic ozonation, the degradation efficiency of 4-chloro-2-nitrophenol was higher at low pH conditions (pH 3.0) than high pH (pH 7–9). This result was not in accordance with ozonation alone, following which higher pH had positive effect on the degradation of 4-chloro-2-nitrophenol. During the catalytic ozonation of 4-chloro-2-nitrophenol, an increase of nitrate ions in water sample solution was observed. At pH = 3, the concentration of nitrate formed during nano-ZnO catalytic ozonation was 7.08 mg L⁻¹ and the amount of total organic carbon was 54.9% after 30 min.     

QSAR studies of some side chain modified 7-chloro-4-aminoquinolines as antimalarial agents

The quantitative structure–activity relationship (QSAR) analyses were carried out for a series of new side chain modified 4-amino-7-chloroquinolines to find out the structural requirements of their antimalarial activities against both chloroquine sensitive (HB3) and resistant (Dd2) Plasmodium falciparum strain. The statistically significant best 2D QSAR models for Dd2, having correlation coefficient (r²) = 0.9188 and cross validated squared correlation coefficient (q²) = 0.8349 with external predictive ability (pred_r²) = 0.7258 and for HB3, having r² = 0.9024, q² = 0.8089 and pred_r² = 0.7463 were developed by multiple linear regression coupled with genetic algorithm (GA–MLR) and stepwise (SW–MLR) forward algorithm, respectively. The results of the present study may be useful on the designing of more potent analogues as antimalarial agents.     

Investigation of sodium 4-nitrotoluene-2-sulfonate solubility in aqueous organic solutions

The solubility of sodium 4-nitrotoluene-2-sulfonate (NTSNa) in binary solvent mixtures (methanol + water), (ethanol + water), and (2-methoxyethanol + water) was investigated over the temperature range from (288 to 344) K. The mole fraction of water in solvent mixtures ranged from 0 to 0.8. The solubility data are described by the electrolyte non-random two-liquid (E-NRTL) model. The E-NRTL binary interaction parameters are expressed as a function of temperature, and were obtained from the experimental data. The root-mean-square deviations of solubility temperature varied from (0.20 to 1.35) K.     

Phase equilibria study of the binary systems (1-butyl-3-methylimidazolium tosylate ionic liquid + water,or organic solvent)

(Solid + liquid) phase equilibria (SLE) and (liquid + liquid) phase equilibria (LLE) for the binary systems: ionic liquid (IL) 1-butyl-3-methylimidazolim tosylate (p-toluenesulfonate) {[BMIM][TOS] + water, an alcohol (ethanol, or 1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol), or n-hexane, or an aromatic hydrocarbons (benzene, or toluene, or ethylbenzene, or propylbenzene, or thiophene)} have been determined at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (230 to 340) K. For the binary systems containing water, or an alcohol, simple eutectic diagrams were observed with complete miscibility in the liquid phase. As usual, with increasing chain length of the alcohol the solubility decreases. In the case of mixtures {IL + n-hexane, or benzene, or alkylbenzene, or thiophene} the eutectic systems with mutual immiscibility in the liquid phase with an upper critical solution temperature (UCST) were detected. The basic thermal properties of the pure IL, i.e. melting and glass-transition temperatures, as well as the enthalpy of fusion have been measured using a differential scanning microcalorimetry technique (DSC). Density at high temperatures was determined and extrapolated to 298.15 K. Well-known UNIQUAC, Wilson and NRTL equations have been used to correlate experimental SLE data sets for alcohols and water. For the systems containing immiscibility gaps {IL + n-hexane, or benzene, or alkylbenzene, or thiophene}, parameters of the LLE correlation equation have been derived using only the NRTL equation.     

(Vapour + liquid) equilibria,densities, excess molar volumes,refractive indices,speed of sound for (methanol + allyl acetate) and (vinyl acetate + allyl acetate)

Isobaric (vapour  +  liquid) equilibria were determined atp =  101.3 kPa for {methanol  +  allyl acetate (3-acetoxy-1-propene)} and {vinyl acetate (1-acetoxyethylene)  +  allyl acetate}. The thermodynamic consistency of the experimental data was determined with a modified Dechema test. The activity coefficients were correlated with Margules, van Laar, NRTL, UNIQUAC, Wilson and ASOG. Densities, excess molar volumes, refractive indices, speed sounds and changes of refractive index and speed sound on mixing have been determined at 298.15 K and the results fitted to Redlich–Kister polynomials. Allyl acetate can be a possible solvent for extractive distillation.     

Solubility of hyperbranched polymer,Boltorn W-3000, in alcohols,ethers and hydrocarbons

(Solid/liquid + liquid) phase diagrams at ambient pressure have been determined for the hyperbranched polymer, Boltorn W3000 with alcohols (methanol, ethanol, 1-propanol, 1-hexanol, 1-decanol), or with ethers (tert-butyl methyl ether, tert-butyl ethyl ether), or with hydrocarbons (n-hexane, n-heptane, benzene, toluene) by a dynamic method from T = 240 K to the boiling temperature of the solvent. (Solid + liquid) phase equilibria with immiscibility in the liquid phase were detected for B-W3000 with the alcohols and aliphatic hydrocarbons. The upper critical solution temperatures, UCSTs, were measured for (B-W3000 + 1-hexanol and 1-decanol) systems. The experimental results of (solid + liquid) phase equilibria have been correlated using NRTL equation.     

Extraction of propylbenzene or butylbenzene from dodecane using 4-methyl-N-butylpyridinium tetrafluoroborate, [mebupy][BF4], as an ionic liquid at different temperatures

Equilibrium tie line data have been determined for the two ternary liquid systems, namely {dodecane + propylbenzene + [mebupy][BF₄]} and {dodecane + butylbenzene + [mebupy][BF₄]} at temperatures (313, 323, and 333) K and atmospheric pressure. The effects of temperature and solvent to feed ratio upon solubility, selectivity, and distribution coefficient were investigated experimentally. The reliability of the experimental data was tested using the Othmer–Tobias correlation. The experimental results were regressed to estimate the interaction parameters between each of the three pairs of components for the UNIQUAC and the NRTL models as a function of temperature. In addition, the LLE data were also correlated with the UNIQUAC and NRTL models in a satisfactory manner.     

Measurement and correlation of the solubility of genistin in eleven organic solvents from T = (283.2 to 323.2) K

The solubilities of genistin in pure solvents including tetrahydrofuran, acetone, ethyl acetate, acetonitrile, isopropanol, n-butyl alcohol, methanol, cyclohexane, n-hexane, chloroform and ethanol were determined by the high performance liquid chromatography (HPLC) analysis method at T = (283.2, 293.2, 303.2, 313.2 and 323.2) K. The fusion enthalpy of genistin was estimated by the group contribution method. The solubility data of genistin were correlated by the simplified thermodynamic model, the modified Apelblat model, λh model and NRTL (Non-Random Two-Liquid) model. The calculated values by all models were in good agreement with the experimental values and however, the NRTL model could give better correlation results than other three models.     

Solubility of ethyl-(2-hydroxyethyl)-dimethylammonium bromide in alcohols (C2–C12)

The solubilities of a novel third generation of the precursor of ionic liquids, named ethyl-(2-hydroxyethyl)-dimethylammonium bromide, C₂Br, in alcohols {ethanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol, 1-dodecanol, 2-butanol, 2-methyl-2-propanol (tert-butyl alcohol)} have been measured by a dynamic method from 240 to 440 K.The solubility of ethyl-(2-hydroxyethyl)-dimethylammonium bromide in primary alcohols decreases with an increase of the molecular weight of the alcohol from C₂ to C₁₂. The differences in solubilities between the primary and secondary alcohols are not significant. The solubility of C₂Br in tert-butyl alcohol is much lower than in 1-butanol and 2-butanol.The data were correlated by means of the UNIQUAC ASM, NRTL1 and NRTL2 equations, utilizing parameters derived from the (solid + liquid) equilibrium (SLE) data. The root-mean-square deviations of the solubility temperatures for all calculated data are from 2.36 to 7.17 K and depend on the particular equation used. In the calculations, the existence of a solid–solid first-order phase transition in pure C₂Br has also been taken into account.     

Investigation of 1-(2-carboxyethyl)-3-methylimidazolium chloride[HOOCEMIM][Cl] ionic liquid effect on water activity and solubility of l-serine at T = 298.15 K

Water activity measurements by the isopiestic method have been carried out on the aqueous ternary system of {l-serine + 1-(2-carboxyethyl)-3-methylimidazolium chloride[HOOCEMIM][Cl]} ionic liquid and the aqueous binary system of IL at T = 298.15 K and atmospheric pressure. The data obtained were used to calculate the vapor pressure and osmotic coefficient of solution as a function of concentration. The experimental results for the activity of water were accurately correlated with segment-based local composition models of modified NRTL and UNIQUAC. The fitting quality of the above models has been favorably compared with the NRTL and Wilson models. From these data, the corresponding activity coefficients have been calculated. For the same system, the solubility of the l-serine at various [HOOCEMIM][Cl] ionic liquid concentrations was measured at T = 298.15 K using the gravimetric method. A chemical model was employed to describe the dissociation equilibria of all amino acid species with hydrogen ions in water. Moreover, for l-serine, the chemical model indicated that the formation of cations is insignificant in the [HOOCEMIM][Cl] solution. Also the above local composition models were used to predict the solubility of l-serine in aqueous IL solutions. To provide information regarding (solute + solute) interactions, transfer Gibbs free energies (ΔG_tr) of amino acid from water to aqueous IL solutions have been determined.     

Thermodynamics of fuels with a bio-synthetic component (IV): (Vapor + liquid) equilibrium data for the ternary mixture (ethyl 1,1-dimethylethyl ether + 1-hexene + toluene) at T = 313.15 K

The paper reports experimental p–x data for the ternary system (ethyl 1,1-dimethylethyl ether + 1-hexene + toluene) at T = 313.15 K. The ether, synthesized from ethanol of biological origin, increases the interest of this compound as an additive for gasolines. An isothermal total pressure cell was used for the measurements. Data reduction by Barker’s method provides correlations for G^E, using Wilson, NRTL, UNIQUAC models and the Wohl expansion for the ternary system and the calculation of the vapor phase composition. Good results are obtained for the correlation by all the models.     

Experimental and correlational study of phase equilibria in aqueous mixtures of phosphoric acid with aromatic hydrocarbons at various temperatures

Experimental solubility and tie-line data were obtained for (water + phosphoric acid + ethyl benzene or cumene) ternary systems at T = (298.15, 308.15 and 318.15) K and P = 101.32 kPa. The experimental tie-line values were correlated using the thermodynamic models of UNIQUAC and NRTL. The quality of the experimental results was determined through the Othmer–Tobias and Hand plots. Distribution coefficients and separation factors were evaluated over the immiscibility regions. The influence of temperature on biphasic region is found to be negligible.