(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.     

Thermodynamics of binary mixtures containing N-methyl-2-pyrrolidinone: VLE measurements for systems with ethers—Comparison with the Mod. UNIFAC (Do) and DISQUAC models—Predictions for VLE,GmE, HmE and SLE

Isothermal vapour–liquid equilibrium data, (VLE) have been measured by an ebulliometric method for four binary mixtures of N-methyl-2-pyrrolidinone (NMP) with dipropyl ether at T = 353.15 K and T = 373.15 K, or dibutyl ether at T = 373.15 K, or methyl 1,1-dimethylethyl ether (MTBE) at T = 333.15 K, or methyl 1,1-dimethylpropyl ether (MTAE) at T = 353.15 K, in the pressure range from P = 0 kPa to P = 135 kPa.The experimental VLE results have been correlated using a three parameter Redlich–Kister expansion. All these systems present positive deviations from Raoult's law.Binary mixtures of NMP with dipropyl ether, dibutyl ether, MTBE and MTAE have been investigated in the framework of the Modified UNIFAC (Do) and DISQUAC models. The reported new interaction parameters for the NMP-group (NCO) and the ether group (O) give much better results than known from literature predictions of the thermodynamic properties, including vapour–liquid equilibrium, excess molar Gibbs energy, molar excess enthalpies and solid–liquid equilibrium. Our experimental data and literature data for binary mixtures containing NMP and ethers were compared to the results of predictions with the Mod. UNIFAC (Do) and DISQUAC models.     

(Liquid + liquid) phase equilibria of 1-alkyl-3-methylimidazolium methylsulfate with alcohols,or ethers,or ketones

Solubilities of binary mixtures that contain a room-temperature ionic liquid and an organic solvent – namely, 1,3-dimethylimidazolium methylsulfate, [mmim][CH₃SO₄], or 1-butyl-3-methylimidazolium methylsulfate, [bmim][CH₃SO₄] with an alcohol (hexan-1-ol, or octan-1-ol, or nonan-1-ol, or decan-1-ol), or an ether (dipropyl ether, or dibutyl ether, or methyl-1,1-dimethylethyl ether, or methyl-1,1-dimethylpropyl ether), or a ketone (pentan-2-one, or pentan-3-one, or hexan-2-one, or heptan-4-one, or cyclopentanone) – have been measured by a visual method from T = 270 K to the boiling temperature of the solvent. The (liquid + liquid) equilibria curves were predicted by the COSMO-RS method. For [bmim][CH₃SO₄], the COSMO-RS predictions correspond better with experimental results than do the predictions for [mmim][CH₃SO₄].Complete miscibility has been observed in the systems of [mmim][CH₃SO₄] with water and with alcohols ranging from methanol to octan-1-ol and that of [bmim][CH₃SO₄] with water and with alcohols ranging from methanol to decan-1-ol at the temperature T = 310 K.     

Excess molar enthalpies of ternary mixtures (dibutyl ether or dipropyl ether + 2,2-dimethylbutane + 2,3-dimethylbutane) at the temperature 298.15 K

Excess molar enthalpies, measured at the temperature 298.15 K and atmospheric pressure conditions by means of a flow microcalorimeter, are reported for the ternary mixtures {x₁(dibutyl ether or dipropyl ether) + x₂ 2,2-dimethylbutane + (1 ? x₁ ? x₂) 2,3-dimethylbutane}. A smooth representation of the results is described and the constant-enthalpy contours for each ternary system are displayed on the respective Roozeboom diagrams. The results serve to show that good estimates of the excess molar enthalpies of the ternary systems can be obtained from the Liebermann–Fried model by using the physical properties of the constituent pure components and the parameters determined from the binary mixtures of these components.     

The excess molar volumes and enthalpies of (N-methyl-2-pyrrolidinone + an alcohol) atT = 298.15 K and the application of the ERAS theory

Excess molar volumes V_m^EatT =  298.15 K and atmospheric pressure are reported for (N -methyl-2-pyrrolidinone  +  propan-2-ol, or butan-1-ol, or butan-2-ol, or 2-methylpropan-1-ol ). TheV_m^E have been calculated from measured values of density using the vibrating tube technique. The results are discussed in terms of the hydrogen bonding and other intermolecular association. Excess molar enthalpiesH_m^E at T =  298.15 K and atmospheric pressure are reported for (N -methyl-2-pyrrolidinone  +  propan-1-ol, or propan-2-ol, or butan-1-ol, or butan-2-ol, or 2-methylpropan-1-ol). The H_m^Ehave been obtained using flow calorimetry. The experimental results have been correlated and compared with the results from the Extended Real Associated Solution (ERAS) theory. The parameters adjusted to the mixtures properties are two cross association parameters and the interaction parameter responsible for the exchange energy of the van der Waals interactions. Self-association parameters of the alcohols and NMP are taken from the literature.     

Vapor–liquid equilibria and excess properties of octane + 1,1-dimethylpropyl methyl ether (TAME) mixtures

Vapor–liquid equilibrium (VLE) data are reported for the binary mixtures formed by octane and the branched ether 1,1-dimethylpropyl methyl ether (tert-amyl methyl ether or TAME). A Gibbs–van Ness type apparatus was used to obtain total vapor pressure measurements as a function of composition at 298.15, 308.15, 318.15 and 328.15 K. The system shows positive deviations from Raoult’s law. These VLE data are analyzed together with data previously reported for octane+TAME mixtures: VLE data at 323.15 and 423.15 K, excess enthalpy (H_m^E) data at 298.15 and 313.15 K and excess volume (V_m^E) data at 298.15 K. The UNIQUAC model, the lattice–fluid (LF) model, and the Flory theory are used to simultaneously correlate VLE and H_m^E data. The two latter models are then used to predict V_m^E data. The original UNIFAC group contribution model and the modified UNIFAC (Dortmund model) are used to predict VLE data.     

The excess molar enthalpies of (N-methyl-2-pyrrolidinone + mono-, or di-, or trichlorobenzene) atT = 298.15 K

Excess molar enthalpies H_m^EatT =  298.15 K are reported for (N -methyl-2-pyrrolidinone  +  chlorobenzene, or 1,2-dichlorobenzene, or 1,3-dichlorobenzene, or 1,2,4,-trichlorobenzene). The values ofH_m^E were obtained by using the flow calorimetric method. All the mixtures, over the whole composition range, are formed exothermically. The H_m^Eresults are discussed in terms of the NRTL and UNIQUAC models.     

Thermodynamics of isomeric hexynes + MTBE binary mixtures

The vapor pressures of liquid hex-1-yne or hex-2-yne + methyl 1,1-dimethylethyl ether (MTBE) binary mixtures and of the three pure components were measured by a static method at several temperatures between 263 and 343 K. These data were correlated with the Antoine equation. Excess molar Gibbs energies G^E were calculated for several constant temperatures, taking into account the vapor-phase imperfection in terms of the second molar virial coefficients, and were fitted to the Redlich–Kister equation. Calorimetric excess enthalpy H^E measurements, for these binary mixtures, are also reported at 298.15 K. The experimental VLE and H^E data were used, examining the binary mixtures hex-1-yne or hex-2-yne + MTBE in the framework of the DISQUAC and modified UNIFAC (Do) models. The DISQUAC calculations, reporting a new set of interaction parameters for the contact carbon–carbon triple bond/oxygen ether, is regarded as a preliminary approach.     

Volume changes on mixing perfluoroalkanes with alkanes or ethers at 298.15 K

Excess molar volumes V^E at 298.15 K have been determined by means of a vibrating-tube densimeter for binary mixtures of n-hexane with a perfluoroalkane, C₅–C₈, and of perfluorohexane with a n-alkane, C₅–C₈, or an ether (diethyl, dipropyl, dibutyl, butyl methyl, and butyl ethyl ether). The systems perfluoropentane+hexane, perfluorohexane+pentane or hexane or diethyl ether have been investigated in the entire mole fraction range, while the other mixtures only in the miscibility regions. The observed V^E values are positive (up to 5.5 cm³ mol⁻¹) and among the largest known for non-electrolyte systems. Limiting partial molar volumes, $\text{V}\text{̄}\text{°}$, have been evaluated for each component of the examined mixtures. The behaviour of $\text{V}\text{̄}\text{°}$ has been discussed in terms of the scaled particle theory (SPT) and of a simple group additivity scheme based on surface interactions. An estimate has been made of the average separation distance of solvent from solute molecules.     

The excess molar enthalpies and volumes of (N-methyl-2-pyrrolidinone + an alkan-1-ol) at T=298.15 K

The excess molar enthalpies H_m^E, for the mixtures (N-methyl-2-pyrrolidinone + ethanol, or pentan-1-ol, or hexan-1-ol, or heptan-1-ol, or octan-1-ol, or nonal-1-ol, or decan-1-ol, or undecan-1-ol) at T=298.15 K and atmospheric pressure have been obtained using flow calorimetry. Excess molar volumes at T=298.15 K and atmospheric pressure have also been determined for (N-methyl-2-pyrrolidinone + nonal-1-ol, or decan-1-ol, or undecan-1-ol) from density measurements using a vibrating tube densimeter. The experimental results have been correlated and compared with the results from the Flory–Benson–Treszczanowicz (FBT) theory and from the Extended Real Associated Solution (ERAS) model. The ERAS model accounts free volume effects according to the Flory–Patterson model and additionally association effects between the molecules involved. For the mixtures studied here the association effects arise from the self association of an alkan-1-ol molecules and also the cross-association of the proton of the alkan-1-ol with carbonyl oxygen of N-methyl-2-pyrrolidinone (NMP) molecule. The parameters adjusted to the mixtures properties are two cross-association parameters and the interaction parameter responsible for the exchange energy of the van der Waals interactions. Self-association parameters of the alcohols and NMP are taken from the literature.     

Thermodynamics of biofuels: Excess enthalpies for binary mixtures involving ethyl 1,1-dimethylethyl ether and hydrocarbons at different temperatures using a new flow calorimeter

Excess molar enthalpies for the binary systems: (ethyl 1,1-dimethylethyl ether + heptane); (ethyl 1,1-dimethylethyl ether + cyclohexane); (ethyl 1,1-dimethylethyl ether + toluene); (cyclohexane + toluene), and (toluene + heptane) have been measured at T = (298.15 and 313.15) K using a new isothermal flow calorimeter developed in the laboratory. The technique was previously checked by measuring test systems. The experimental results have been correlated with the Redlich–Kister polynomial equation. The mixing effects observed and the influence of the temperature are discussed.     

Excess molar enthalpies of the binary systems: (Dibutyl ether + isomers of pentanol) at T = (298.15 and 308.15) K

In this work, we present the experimental measurements of excess molar enthalpies for the binary systems of dibutyl ether with different isomers of pentanol: 1-pentanol, 2-pentanol, 3-pentanol, 3-methyl-2-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol and 2-methyl-2-butanol; all of them at T = (298.15 and 308.15) K and atmospheric pressure. Our goal was to determine the influence of the OH-group position on the different isomers of pentanol in the excess molar enthalpies of the binary systems studied. For this purpose we have analysed their experimental effective-reduced dipole moments. All values of excess molar enthalpies for the mixtures studied are positive whereas the results obtained for the effective-reduced dipole moments of the isomers of pentanol are similar.     

Quaternary (liquid + liquid) equilibria for (methanol + 2,2,4-trimethylpentane + toluene + 1,1-dimethylpropyl methyl ether or 1,1-dimethylethyl methyl ether) at T = 298.15 K

The experimental equilibrium tie-lines of two quaternary mixtures for (methanol + 1,1-dimethylpropyl methyl ether + toluene + 2,2,4-trimethylpentane) and (methanol + 1,1-dimethylethyl methyl ether + toluene + 2,2,4-trimethylpentane) were measured at the temperature 298.15 K and ambient pressure. The quaternary experimental results and their constituent ternaries have been satisfactorily predicted using binary parameters alone obtained by an associated-solution model that takes into account association of methanol molecules and solvation between (methanol + polar molecules) with allowance for a non-polar interaction given by an extended form of the UNIQUAC model. The results are further compared with those correlated by modified and extended forms of the UNIQUAC models that include multi-body interaction parameters in addition to binary ones.     

Excess molar enthalpies and excess molar heat capacities of (2-butanone + cyclohexane,or methylcyclohexane,or benzene,or toluene,or chlorobenzene,or cyclohexanone) atT = 298.15 K

Excess molar enthalpies of (2- butanone  +  cyclohexane, or methylcyclohexane, or toluene, or chlorobenzene, or cyclohexanone) and excess molar heat capacities of (2- butanone  +  benzene, or toluene, or chlorobenzene, or cyclohexanone) were measured atT =  298.15 K. Aliphatic systems were endothermic and the chlorobenzene system was exothermic. On the other hand, the toluene system changed sign to be S-shaped similar to the benzene system reported by Kiyohara et al. The values of excess molar enthalpies of the present mixtures were slightly larger than the corresponding mixtures of cyclohexanone already reported. Excess molar heat capacities of aromatic systems were characteristically S-shaped for the mixture containing aromatics. The values of the present mixtures were less than the corresponding mixtures of cyclohexanone. The mixture (2-butanone  +  cyclohexanone) was endothermic forH_m^E and negative for C_p,m^E.     

Excess molar enthalpies and excess molar volumes of (1,3-dimethyl-2-imidazolidinone + an aromatic hydrocarbon) atT = 298.15 K

Excess molar enthalpies H_m^Eand excess molar volumesV_m^E of (1,3-dimethyl-2-imidazolidinone  +  benzene, or methylbenzene, or 1,2-dimethylbenzene, or 1,3-dimethylbenzene, or 1,4-dimethylbenzene, or 1,3,5-trimethylbenzene, or ethylbenzene) over the whole range of compositions have been measured at T =  298.15 K. The excess molar enthalpy values were positive for five of the seven systems studied and the excess molar volume values were negative for six of the seven systems studied. The excess enthalpy ranged from a maximum of 435 J · mol ^− 1for (1,3-dimethyl-2-imidazoline  +  1,3,5-trimethylbenzene) to a minimum of  − 308 J · mol ^− 1for (1,3-dimethyl-2-imidazoline  +  benzene). The excess molar volume values ranged from a maximum of 0.95cm³mol ^− 1 for (1,3-dimethyl-2-imidazoline  +  ethylbenzene) and a minimum of  − 1.41 cm³mol ^− 1for (1,3-dimethyl-2-imidazoline  +  methylbenzene). The Redlich–Kister polynomial was used to correlate both the excess molar enthalpy and the excess molar volume data and the NRTL and UNIQUAC models were used to correlate the enthalpy of mixing data. The NRTL equation was found to be more suitable than the UNIQUAC equation for these systems. The results are discussed in terms of the polarizability of the aromatic compound and the effect of methyl substituents on the benzene ring.     

Limiting partial molar volumes of tetra-n-alkylammonium perchlorates inN,N- dimethylacetamide,triethylphosphate and dimethyl sulfoxide atT = 298.15 K

The densities of tetraalkylammonium perchlorates R₄NClO₄(R  =  methyl, or ethyl, or propyl, or butyl) and ammonium perchlorate solutions in N, N - dimethylacetamide, dimethyl sulfoxide, and triethylphosphate have been measured over the whole composition range atT =  298.15 K. From these densities, apparent and limiting partial molar volumes of the electrolytes and ions have been evaluated and used to obtain the partial molar volume for theClO₄ ⁻  anion.     

Characterization and modelling of a gasoline containing 1,1-dimethylethyl methyl ether (MTBE), diisopropyl ether (DIPE) or 1,1-dimethylpropyl methyl ether (TAME) as fuel oxygenate based on new isothermal binary vapour–liquid data

Experimental isothermal P–x data at T=313.15 K for seven binary systems (1,1-dimethylethyl methyl ether (MTBE)+2,2,4-trimethylpentane); (1,1-dimethylethyl methyl ether (MTBE)+toluene); (toluene+2,2,4-trimethylpentane); (toluene+1-hexene); (toluene+cyclohexane); (2,2,4-trimethylpentane+1-hexene) and (2,2,4-trimethylpentane+cyclohexane) are reported. Data reduction by Barker’s method provides correlations for G^E using the Margules equation, Wilson, NRTL and UNIQUAC models, which have been applied successfully. We have compared the behaviour in the vapour–liquid equilibrium of the aromatic compounds benzene and toluene and the paraffins heptane and 2,2,4-trimethylpentane. And finally we have modelled a gasoline of five components using the Wilson model, and we have compared the influence of three different ethers used as oxygenated additives in gasolines.     

The excess molar volumes of (hydrocarbon + branched chain ether) systems at 298.15 K and 308.15 K, and the application of PFP theory

The excess molar volumes, V_m^E, have been calculated from measured density values over the whole composition range at the temperatures 298.15 K and 308.15 K and under atmospheric pressure for the 12 mixtures {hydrocarbon (heptane, 2,2,4-trimethylpentane, 1-heptene or toluene) + branched chain ether (methyl 1,1-dimethylethyl ether, ethyl 1,1-dimethylethyl ether or methyl 1,1-dimethylpropyl ether)}. The excess volumes of all the mixtures except (toluene + ether) are positive over the whole composition range. The experimental results have been correlated and compared with the results from Prigogine-Flory-Patterson (PFP) theory.     

Densities,speeds of sound,and refractive indices of the ternary mixtures (toluene + methyl acetate + butyl acetate) and (toluene + methyl acetate + methyl heptanoate) at 298.15 K

Density, ρ, speed of sound, u, and refractive index, n_D, at 298.15 K and atmospheric pressure have been measured over the entire composition range for (toluene + methyl acetate + butyl acetate) and (toluene + methyl acetate + methyl heptanoate) systems. Excess molar volumes, V^E, isentropic compressibility, κ_s, isentropic compressibility deviations, Δκ_s, and changes of refractive index on mixing, Δn_D, for the above systems, have been calculated from experimental data and fitted to Cibulka, Singh et al., and Nagata and Sakura equations, standard deviations from the regression lines are shown. Geometrical solution models, Tsao and Smith, Kholer, Jacob and Fitzner, Rastogi et al. were also applied to predict ternary properties from binary contributions.     

Volumetric properties of (an organic compound + di-n-butyl ether) atT = 298.15 K

Excess molar volumes V_m^Eof {di- n -butyl ether (DBE)  +  a monofunctional organic compound} have been determined atT =  298.15 K over the whole composition range by means of a vibrating-tube densimeter. TheV_m^E values were either positive (propylamine, or butylamine, or acetone, or tetrahydrofuran  +  DBE) or negative (methanol, or butanol, or diethyl ether, or cyclopentanone, or acetonitrile  +  DBE). Markedly asymmetric V_m^Ecurves were displayed by (DBE  +  methanol) and (DBE  +  acetonitrile). Partial molar volumes __ V_m^oat infinite dilution in DBE, both from this work and the literature, were analysed in terms of an additivity scheme, and the group contributions thus obtained were discussed and compared with analogous results in water. DBE revealed a greater capability of distinguishing between polar and non-polar solutes, as well as in discriminating differently shaped molecules (unbranched, branched, cyclic). The limiting slopes of apparent excess molar volumes are evaluated and briefly discussed in terms of solute–solute and solute–solvent interactions.