On the density and viscosity of (water + dimethylsulphoxide) binary mixtures

Density and viscosity of (water + dimethylsulphoxide) were measured precisely over the whole composition range at T = (298.15, 303.15, 308.15, 313.15, and 318.15) K. Differences between values from different authors are clarified and more reliable partial molar volumes are obtained.     

Excess molar enthalpies of {diethyl oxalate + (methanol, + ethanol, + 1-propanol,and + 2-propanol)} at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa

A flow-mixing isothermal microcalorimeter was used to measure excess molar enthalpies for four binary systems of {diethyl oxalate + (methanol, + ethanol, + 1-propanol, and + 2-propanol)} at T = (288.2, 298.2, 313.2, and 328.2) K and p = 101.3 kPa. The densities of the diethyl oxalate at different temperature were measured by using a vibrating-tube densimeter. All systems exhibit endothermic behaviour over the whole composition range, which means that the rupture of interactions is energetically the main effect. The excess molar enthalpies increase with temperature and the molecular size of the alcohols. The experimental results were correlated by using the Redlich–Kister equation and two local-composition models (NRTL and UNIQUAC).     

Measurements and modeling for the density of 2-methoxy-2,4,4-trimethylpentane,HE for (methanol + 2-methoxy-2,4,4-trimethylpentane), LLE for (water + 2-methoxy-2,4,4-trimethylpentane) and LLE for (water + methanol + 2-methoxy-2,4,4-trimethylpentane)

Oxygenates are used in gasoline to increase the octane number and reduce carbon monoxide emission. 2-methoxy-2,4,4-trimethylpentane (TOME) is a tertiary ether which can potentially be used in addition with current oxygenates. This compound can be produced by etherification of diisobutylene with methanol. During the etherification, water is formed due to the dehydration of methanol. The appearance of water can cause (liquid + liquid) phase split in the production process. In this work, several physical properties of systems containing water, methanol and TOME are studied for the first time. The liquid density of 2-methoxy-2,4,4-trimethylpentane is presented from T = (298.15 to 408.16) K. Excess enthalpies are reported for the binary system of (methanol + 2-methoxy-2,4,4-trimethylpentane) at (T = 298.15 K). The (liquid + liquid) equilibrium (LLE) for (water + 2-methoxy-2,4,4-trimethylpentane) from T = (283.15 to 318.15) K is determined. The LLE is also reported for the ternary system of (water + methanol + 2-methoxy-2,4,4-trimethylpentane) at T = (283.15 and 298.15) K. The UNIQUAC parameters were regressed to model VLE, excess enthalpy and LLE for the binary and ternary data with one set of parameters.     

Physico-chemical and excess properties of the binary mixtures of methylcyclohexane + ethanol, + propan-1-ol, + propan-2-ol, + butan-1-ol, + 2-methyl-1-propanol,or 3-methyl-1-butanol at T = (298.15, 303.15, and 308.15) K

Physico-chemical properties viz., density, viscosity, and refractive index at temperatures = (298.15, 303.15, and 308.15) K and the speed of sound at T = 298.15 K are measured for the binary mixtures of methylcyclohexane with ethanol, propan1-ol, propan-2-ol, butan-1-ol, 2-methyl-1-propanol, and 3-methyl-1-butanol over the entire range of mixture composition. From these data, excess molar volume, deviations in viscosity, molar refraction, speed of sound, and isentropic compressibility have been calculated. These results are fitted to the polynomial equation to derive the coefficients and standard errors. The experimental and calculated quantities are used to study the nature of mixing behaviours between the mixture components.     

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.     

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.     

(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.     

Measurements and modeling of LLE and HE for (methanol + 2,4,4-trimethyl-1-pentene), and LLE for (water + methanol + 2,4,4-trimethyl-1-pentene)

Excess enthalpy (H^E) for the binary system of (methanol + 2,4,4-trimethyl-1-pentene) (TMP-1) is reported at T = 298.15 K and 101 kPa. (Liquid + liquid) equilibrium (LLE) for the same system is measured at atmospheric pressure (101 kPa). LLE for ternary system of (water + methanol + 2,4,4-trimethyl-1-pentene) is measured at T = (283 and 298) K.The parameters of Non-Random Two-Liquid (NRTL) model were regressed for the system of (methanol + TMP-1) using H^E and LLE from this work combined with isobaric (101 kPa) and isothermal (T = 331 K) VLE data from literature. The NRTL parameters for the binary system of (water + TMP-1) were fitted to a binary LLE data set from literature. NRTL parameters for the binary system of (water + methanol) were taken from ASPEN PLUS. The LLE for the ternary system was modeled by the three binary NRTL interaction parameters systems. The binary and ternary models were compared against the measured data.     

Volumetric behavior of the ternary system (methyl tert-butyl ether + methylbenzene + butan-1-ol) and its binary sub-system (methyl tert-butyl ether + butan-1-ol) within the temperature range (298.15 to 328.15) K

Values of the density and speed of sound were measured for the ternary system (methyl tert-butyl ether + methylbenzene + butan-1-ol) within the temperature range (298.15 to 328.15) K at atmospheric pressure by a vibrating-tube densimeter DSA 5000. Two binary sub-systems were studied and published previously while the binary sub-system (methyl tert-butyl ether + butan-1-ol) is a new study in this work. Excess molar volume, adiabatic compressibility, and isobaric thermal expansivity were calculated from the experimental values of density and speed of sound. The excess quantities were correlated using the Redlich–Kister equation. The experimental excess molar volumes were analyzed by means of both the Extended Real Associated Solution (ERAS) model and the Peng–Robinson equation of state. The novelty of this work is the qualitative prediction of ternary excess molar volumes for the system containing auto-associative compound and two compounds that can hetero-associate. The combination of the ERAS model and Peng–Robinson equation of state could help to qualitatively estimate the real behavior of the studied systems because the experimental results lie between these two predictions.     

Excess molar volumes,and excess molar enthalpies of (N-methyl-2-pyrrolidinone + an ether ) at the temperature 298.15 K

Excess molar volumes V_m^E have been calculated from measured density values over the whole composition range at T =  298.15 K and atmospheric pressure for six { N -methyl-2-pyrrolidinone  +  1,1-dimethylethyl methyl ether, or dipropyl ether, or 1,1-dimethylpropyl methyl ether, or diisopropyl ether, or dibutyl ether, or dipentyl ether}. Excess molar enthalpiesH_m^E were also measured for five { N -methyl-2-pyrrolidinone  +  1,1-dimethylethyl methyl ether, or dipropyl ether, or 1,1-dimethylpropyl methyl ether, or diisopropyl ether, or dibutyl ether} at T =  298.15 K and atmospheric pressure. The results are discussed in terms of intermolecular associations. The experimental results have been correlated with the UNIQUAC and NRTL equations.     

Application of the PFV EoS correlation to excess molar volumes of (1-ethyl-3-methylimidazolium ethylsulfate + alkanols) at different temperatures

The experimental densities for the binary systems of an ionic liquid and an alkanol {1-ethyl-3-methylimidazolium ethylsulfate [EMIM]⁺ [EtSO₄]^? + methanol or 1-propanol or 2-propanol} were determined at T = (298.15, 303.15, and 313.15) K. The excess molar volumes for the above systems were then calculated from the experimental density values for each temperature. The Redlich–Kister smoothing polynomial was used to fit the experimental results and the partial molar volumes were determined from the Redlich–Kister coefficients. For all the systems studied, the excess molar volume results were negative over the entire composition range for all the temperatures. The excess molar volumes were correlated with the pentic four parameter virial (PFV) equation of state (EoS) model.     

Density and activity of pertechnetic acid aqueous solutions at T = 298.15 K

The previous isopiestic investigations of HTcO₄ aqueous solutions at T = 298.15 K are believed to be unreliable, because of the formation of a ternary mixture at high molality. Consequently, published isopiestic molalities for aqueous HTcO₄ solutions at T = 298.15 K were completed and corrected. Binary data (variation of the osmotic coefficient and activity coefficient of the electrolyte in solution in the water) at T = 298.15 K for pertechnetic acid HTcO₄ were determined by direct water activity measurements. These measurements extend from molality m = 1.4 mol · kg⁻¹ to m = 8.32 mol · kg⁻¹. The variation of the osmotic coefficient of this acid in water is represented mathematically. Density variations at T = 298.15 K are also established and used to express the activity coefficient values on both the molar and molal concentration scale. The density law leads to the partial molar volume variations for aqueous HTcO₄ solutions at T = 298.15 K, which are compared with published data.     

(Liquid + liquid) equilibria for (water + 1-propanol + diisopropyl ether + octane,or methylbenzene,or heptane) systems at T = 298.15 K

(Liquid + liquid) equilibria (LLE) data were presented for one ternary system of {water + octane + diisopropyl ether (DIPE)} and three quaternary systems of (water + 1-propanol + DIPE + octane, or methylbenzene, or heptane) at T = 298.15 K and p = 100 kPa. The experimental LLE data were correlated with the modified and extended UNIQUAC models. Distribution coefficients were derived from the experimental LLE data to evaluate the solubility behavior of components in organic and aqueous phases.     

Thermodynamics of the ternary systems: (water + glycine,l-alanine and l-serine + di-ammonium hydrogen citrate) from volumetric,compressibility, and (vapour + liquid) equilibria measurements

The apparent molar volumes and isentropic compressibility of glycine, l-alanine and l-serine in water and in aqueous solutions of (0.500 and 1.00) mol · kg^?1 di-ammonium hydrogen citrate {(NH₄)₂HCit} and those of (NH₄)₂HCit in water have been obtained over the (288.15 to 313.15) K temperature range at 5 K intervals at atmospheric pressure from measurements of density and ultrasonic velocity. The apparent molar volume and isentropic compressibility values at infinite dilution of the investigated amino acids have been obtained and their variations with temperature and their transfer properties from water to aqueous solutions of (NH₄)₂HCit have also been obtained. The results have been interpreted in terms of the hydration of the amino acids. In the second part of this work, water activity measurements by the isopiestic method have been carried out on the aqueous solutions of {glycine + (NH₄)₂HCit}, {alanine + (NH₄)₂HCit}, and {serine + (NH₄)₂HCit} at T = 298.15 K at atmospheric pressure. From these measurements, values of vapour pressure, osmotic coefficient, activity coefficient and Gibbs free energy were obtained. The effect of the type of amino acids on the (vapour + liquid) equilibrium of the systems investigated has been studied. The experimental water activities have been correlated successfully with the segment-based local composition Wilson model. Furthermore, the thermodynamic behaviour of the ternary solutions investigated has been studied by using the semi-ideal hydration model and the linear concentration relations have been tested by comparing with the isopiestic measurements for the studied systems at T = 298.15 K.     

Excess molar volumes and isentropic compressibility of binary systems {trioctylmethylammonium bis(trifluoromethysulfonyl)imide + methanol or ethanol or 1-propanol} at different temperatures

This paper reports measurements of densities for the binary systems of an ionic liquid and an alkanol at T = (298.15, 303.15, and 313.15) K. The IL is trioctylmethylammonium bis(trifluoromethylsulfonyl)imide [OMA]⁺[Tf₂N]^? and the alkanols are methanol, or ethanol, or 1-propanol. The speed of sound at T = 298.15 K for the same binary systems was also measured. The excess molar volumes and the isentropic compressibilities for the above systems were then calculated from the experimental densities and the speed of sound, respectively. Redlich–Kister smoothing polynomial equation was used to fit the excess molar volume and the deviation in isentropic compressibility data. The partial molar volumes were determined from the Redlich–Kister coefficients. For all the systems studied, the excess molar volumes have both negative and positive values, while the deviations in isentropic compressibility are negative over the entire composition range.     

Excess molar volumes and partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and p = 0.1 MPa

The excess molar volumes and the partial molar volumes for (propionitrile + an alkanol) at T = 298.15 K and at atmospheric pressure are reported. The hydrogen bonding between the OH⋯NC groups are discussed in terms of the chain length of the alkanol. The alkanols studied are (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 1-pentanol).The excess molar volume data was fitted to the Redlich–Kister equation The partial molar volumes were calculated from the Redlich–Kister coefficients.     

Contribution to study of the thermodynamics properties of mixtures containing 2-methoxy-2-methylpropane,alkanol, alkane

Excess molar enthalpies for the ternary system {x₁ 2-methoxy-2-methylpropane (MTBE) + x₂ 1-pentanol + (1 − x₁ − x₂) hexane} and the involved binary mixture {x 1-pentanol + (1 − x) hexane}, have been measured at T = 298.15 K and atmospheric pressure over the whole composition range. We are not aware of the existence of previous experimental measurement of the excess enthalpy for the ternary mixture under study in the literature currently available. Values of the excess molar enthalpies were measured using a Calvet microcalorimeter. The results were fitted by means of different variable degree polynomials. The ternary contribution to the excess enthalpy was correlated with the equation due to Verdes et al. (2004), and the equation proposed by Myers–Scott (1963) was used to fit the experimental binary mixture measured in this work. Smooth representations of the results are presented and used to construct constant excess molar enthalpy contours on Roozeboom diagrams. The excess molar enthalpies for the binary and ternary system are positive over the whole range of composition. The binary mixture {x 1-pentanol + (1 − x) hexane} is asymmetric, with its maximum displace toward a high mole fraction of decane. The ternary contribution is also positive with the exception of a range located around the rich compositions of 1-pentanol, and the representation is asymmetric.Additionally, the group contribution model of the UNIFAC model, in the versions of Larsen et al. (1987) [18] and Gmehling et al. (1993) [19] was used to estimate values of binary and ternary excess enthalpy. The experimental results were used to test the predictive capability of several empirical expressions for estimating ternary properties from binary results.     

Excess enthalpies of ternary mixtures of (oxygenated additives + aromatic hydrocarbon) mixtures in fuels and bio-fuels: (Dibutyl-ether + 1-propanol + benzene), or toluene,at T = (298.15 and 313.15) K

New experimental excess molar enthalpy data of the ternary systems (dibutyl ether + 1-propanol + benzene, or toluene), and the corresponding binary systems at T = (298.15 and 313.15) K at atmospheric pressure are reported. A quasi-isothermal flow calorimeter has been used to make the measurements. All the binary and ternary systems show endothermic character at both temperatures. The experimental data for the systems have been fitted using the Redlich–Kister rational equation. Considerations with respect the intermolecular interactions amongst ether, alcohol and hydrocarbon compounds are presented.     

Volumetric properties of ternary (IL + 2-propanol or 1-butanol or 2-butanol + ethyl acetate) systems and binary (IL + 2-propanol or 1-butanol or 2-butanol) and (1-butanol or 2-butanol + ethyl acetate) systems

The experimental densities for the binary or ternary systems were determined at T = (298.15, 303.15, and 313.15) K. The ionic liquid methyl trioctylammonium bis(trifluoromethylsulfonyl)imide ([MOA]⁺[Tf₂N]⁻) was used for three of the five binary systems studied. The binary systems were ([MOA]⁺[Tf₂N]⁻ + 2-propanol or 1-butanol or 2-butanol) and (1-butanol or 2-butanol + ethyl acetate). The ternary systems were {methyl trioctylammonium bis(trifluoromethylsulfonyl)imide + 2-propanol or 1-butanol or 2-butanol + ethyl acetate}. The binary and ternary excess molar volumes for the above systems were calculated from the experimental density values for each temperature. The Redlich–Kister smoothing polynomial was fitted to the binary excess molar volume data. Virial-Based Mixing Rules were used to correlate the binary excess molar volume data. The binary excess molar volume results showed both negative and positive values over the entire composition range for all the temperatures.The ternary excess molar volume data were successfully correlated with the Cibulka equation using the Redlich–Kister binary parameters.     

The effect of temperature and molar mass on the (liquid + liquid) equilibria of (poly ethylene glycol dimethyl ether + di-sodium hydrogen citrate + water) systems: Experimental and correlation

The (liquid + liquid) equilibrium for the {polyethylene glycol dimethyl ether 2000 (PEGDME₂₀₀₀) + di-sodium hydrogen citrate + H₂O} system was studied at T = (298.15, 308.15 and 318.15) K and atmospheric pressure (≈85 kPa). The free energies, enthalpies and entropies of cloud points were calculated in order to investigate the driving force formation of this two-phase system. To investigate the effect of molar mass of the polymer on the binodals and tie-lines, similar measurements were also made at T = 298.15 K on this two-phase system consisting of the PEGDME with molar masses of 500 and 250 g ⋅ mol⁻¹. The effective excluded volume model was used for representation of the phase-forming ability in PEGDME systems. An empirical and the Merchuck equations with the temperature dependency were used to correlate the binodal curves. The Othmer–Tobias and Bancraft and Setschenow equations, the osmotic virial and the extended NRTL models were used to fit the tie-line data.