Excess Molar Volumes Of Mixtures Research Articles

Thermodynamic properties of binary mixtures of methyl acetate and some selected ketonesat varying compositions and temperatures

Density and viscosity measurements of binary mixtures of methyl acetate with propanone, butan-2-one and pentan-2-one were carried out at varying compositions (0 to 1) of methyl acetate and temperatures of 25, 30, 35 and 40◦C. The experimental data obtained were correlated with the Redlich-Kister polynomial equation from where excess molar volumes (VE ), excess viscosities (ηE), excess Gibbs free energies of activation for viscous flow (ΔG*E ), fitting coefficients and standard deviations of the mixtures were calculated. The ηE values were positive for mixtures of butan-2-one and pentan-2-one at all compositions and temperatures but gradually decrease with increasing composition and temperature. The mixtures of methyl acetate with propanone showed negative values of excess viscosity at all compositions of methyl acetate. The negative values are observed to be directly proportional to temperature. The values of VE for mixtures of methyl acetate + propanone system display positive deviations at lower compositions (0-0.4) and negative for higher mole fractions. The excess molar volumes of mixtures of butan-2-one and pentan-2-one are negative at the studied compositions and temperatures with a minimum at 0.3 composition and subsequent gradual decrease in negativity with increasing composition. The excess Gibbs free energy of activation for viscous flow (ΔG*E ) are positive at all compositions and temperatures and reaches a maximum at 0.3 composition above which it decreases. These results have been interpreted on the basis of the type and nature of interactions as well as differences in molecular architecture between the solvent mixtures.

An Investigation of the Properties of Binary and Ternary Mixtures Containing Morpholine

The densities of binary and ternary mixtures of morpholine with dimethyl sulfoxide and N-methyl-2-pyrrolidone are experimentally studied at 293.15 K and atmospheric pressure, density deviations and excess molar volumes of mixtures are calculated from experimental data, concentration dependences for binary systems are described by the Redlich–Kister polynomial, and density isoline diagrams of the morpholine–dimethyl sulfoxide–N-methyl-2-pyrrolidone system are plotted.

Thermodynamic study of binary mixtures of propilophenone + 2-propanol, 2-butanol, 2-pentanol, or 2-hexanol at temperatures of 293.15 to 323.15 K: Modeling by Prigogine-Flory-Patterson theory

In the present work, the density and viscosity of binary mixtures of propiophenone (PP) + 2-propanol, PP + 2-butanol, PP + 2-pentanol, or PP + 2-hehanol were measured over all composition range and in the temperature range of 293.15 to 323.15 K at ambient pressure (0.1 MPa). Using the experimental data of density and viscosity, the excess molar volume and viscosity deviation were calculated and correlated by applying the Redlich-Kister equation. The results show that the excess molar volume of all mixtures is negative over the entire composition range at all temperatures and become more negative with increasing temperature. Also, the viscosity deviation of all mixtures is negative over the whole composition range at all temperatures and become less negative with increasing temperature. The excess molar volumes of mixtures were correlated by using Prigogine-Flory-Patterson (PFP) theory and the agreement between the calculated values with experimental data is good.

Densities and excess molar volumes of mixtures containing diesel, biodiesel and alkanols at temperatures from 288.15 to 313.15 K

The present work is focusing on the synthesization and physico-chemical properties of Jatropha curcas biodiesel with diesel and alcohols. The densities of binary diesel (2) + 1-alkanols (C 3 or C 4 ) (3) and ternary Jatropha curcas biodiesel (1) + diesel (2) + 1-alkanols (C 3 or C 4 ) (3) blends have been reported over full range of composition at temperatures within range 288.15 to 313.15 K. Also densities of Jatropha curcas biodiesel (1) + diesel or 1-alkanols (C 3 or C 4 ) (2) blends have been measured at 313.15 K. Excess molar volumes, V E , V 123 E of binary and ternary blends were calculated from the measured data and the derived properties were correlated to composition using Redlich–Kister equation. A reasonable agreement was found between the measured and estimated values. Further, densities and excess molar volumes data were reasoned to discuss molecular interactions taking into consideration effect of composition and temperature.

Selection and characterization of non-ideal ionic liquids mixtures to be used in CO2 capture

Due to the costs involved, the capture of CO2 in post-combustion is not currently seen as economically viable. Aiming at changing the perception of post-combustion CO2 from a costly and non-profitable process to a valuable commodity and fostering the development of the next-generation of technologies, novel solvents and their mixtures have been investigated. In this work, mixtures of non-volatile ionic liquids were screened by COSMO-RS aiming to find mixtures with positive excess volumes that could present an increased CO2 capture by physical sorption. The most promising mixtures identified by COSMO-RS, [C4C1im][DMP] or [C4C1im][NTf2] + carboxylate-based protic ILs were characterized through the measurement of their thermophysical properties, namely density and viscosity. Both properties were measured for pure ILs and their binary mixtures at different temperatures and compositions. The temperature dependence of density of pure ILs was described using the Gardas and Coutinho model while viscosity was accurately described using the Vogel−Tammann−Fulcher equation. The Redlich-Kister equation was used to predict the excess molar volumes and the non-ideality of the mixtures’ viscosity was assessed using the Grunberg and Nissan mixing law. The excess molar volumes for mixtures containing [C4C1im][DMP] show large positive values all over the range of compositions and temperatures, making them good candidates for CO2 capture. To the best of our knowledge, the excess molar volumes obtained in this work were the highest reported so far. COSMO-RS was able to correctly predict the trend of the experimental excess molar volumes for these mixtures. Regarding viscosity, mixtures of [C4C1im][DMP] with the carboxylate-based protic ILs led to the desired viscosity decrease compared to the pure aprotic IL, and large deviations from ideality were observed. The mixing of ILs is thus an efficient way to fine-tune the properties, in this case decreasing the viscosity while increasing the sorption capacity.

Densities and Viscosities at 293.15–373.15 K, Speeds of Sound and Bulk Moduli at 293.15–333.15 K, Surface Tensions, and Flash Points of Binary Mixtures of n-Hexadecane and Alkylbenzenes at 0.1 MPa

The viscosities and densities (293.15–373.15 K), speeds of sound (293.15–333.15 K), surface tensions (room temperature), and flash points were measured for binary mixtures of n-hexadecane and alkylbenzenes (hexylbenzene, octylbenzene, dodecylbenzene), which are components of diesel fuel. Increasing the temperature decreased densities, and excess molar volumes of mixtures were higher for hexylbenzene mixtures than for octylbenzene mixtures and insignificantly different from zero for dodecylbenzene mixtures. The decrease in excess molar volume with increasing alkyl chain length is consistent with other binary mixtures of n-hexadecane and alkylbenzenes. Increasing the temperature decreased viscosities, and the McAllister three-body model successfully modeled viscosity with the compound in the mixture with the highest individual viscosity having the largest fitted interaction parameter. Mixture flashpoints, speed of sounds, bulk moduli, and surface tensions fell between the pure component values. For n-hexade...

Excess Molar Volumes for Three- and Four-Component Mixtures Simulating the Binary Mixture (Cyclohexane + Hexadecane)

Excess molar volumes of mixtures of cyclohexane and pseudocyclohexane (an equimolar mixture of cyclopentane + cycloheptane) with hexadecane and various pseudohexadecanes (equimolar mixtures of tetradecane + octadecane, decane + docosane, or octane + tetracosane) have been measured at 313.15 K. The results for the multicomponent mixtures are compared with those for the binary mixtures and they show that n-alkanes obey, not quite within experimental uncertainty, an extended principle of congruence with cyclohexane as the other component, whereas mixtures of pseudocyclohexane with hexadecane do not obey the extended principle.

Measurement and correlation of excess molar volumes for mixtures of 1-propanol and aromatic hydrocarbons

Excess molar volumes (V m E ) have been measured at 303.15 K for 1-propanol+benzene or toluene or o- or m- or p-xylene mixtures using V-shape dilatometer. The V m E values, for an equimolar composition, vary in the order: benzene>toluene∼m-xylene>o-xylene>p-xylene. The V m E data have been used to calculate partial molar volumes, excess partial molar volumes, and apparent molar volumes of 1-propanol and aromatic hydrocarbons over the entire range of composition. The excess volume data have also been interpreted in terms of graph-theoretical approach and Prigogine-Flory-Patterson theory (PFP). While PFP theory fails to predict the V m E values for systems with s-shaped V m E versus x1 graph, the V m E values calculated by graph theory compare reasonably well with the corresponding experimental values. This graph theory analysis has further yielded information about the state of aggregation of pure components as well as of the mixtures.

Excess molar volumes of binary mixtures of aliphatic alcohols (C 1–C 5) with Nitromethane over the temperature range 293.15 to 308.15 K: Application of the ERAS model and cubic EOS

Densities were measured for the binary mixtures of methanol, ethanol, 1-propanol, 1-butanol with nitromethane at temperatures (293.15, 298.15, 303.15 and 308.15) K and for 1-pentanol with nitromethane at temperatures (303.15 and 308.15) K and atmospheric pressure. Densities were determined using a vibrating-tube densimeter. Excess molar volumes as a function of mole fraction were derived, and the computed results were fitted to the Redlich–Kister equation. Excess molar volumes of mixtures studied were consistently described by the ERAS model. Also The Peng–Robinson–Stryjek–Vera (PRSV) equation of state was applied, in combination with simple mixing rules.

Compressibility of ethylene glycol-dimethyl sulfoxide mixtures over the pressure range 0.1–100 MPa at 308.15 K

Compressibility coefficients k were measured for binary ethylene glycol (EG)-dimethyl sulfoxide (DMSO) mixtures over the whole composition range at pressures of 0.1–100 MPa and temperature 308.15 K. Excess molar volumes of mixtures, partial molar volumes of EG and DMSO, and changes in the excess molar Gibbs energy were calculated. The concentration dependences of compressibility factors k passed a minimum at pressures of ∼10 MPa. The k coefficient increased as the pressure grew, and the dependence became linear. The composition dependences of the specific volumes of mixtures passed minima at x ∼ 0.5 as the pressure increased (x is the mole fraction of dimethyl sulfoxide). The excess molar volumes were negative (EG-DMSO mixtures formed with compression). Changes in the excess molar Gibbs energy characterized the stabilizing action of pressure on the EG-DMSO system.

Densities and excess molar volumes for mixtures of methanol with other alcohols at temperatures (288.15–313.15 K)

Densities have been measured for the binary mixtures of methanol with ethanol, isomers of propanol and butanol over the entire composition range at 288.15, 293.15, 298.15, 303.15, 308.15, 313.15 K. The density data have been used to calculate the molar volumes, thermal expansion coefficients and their excess values. The excess parameters have been fitted to the Redlich–Kister polynomial equation. The values of the molar volumes, excess molar volumes, thermal expansion coefficients and excess thermal expansion coefficients have been analyzed as a function of the mole fraction and the carbon chain length.

Excess Molar Enthalpies and Excess Molar Volumes for Mixtures of 1,3-Dimethyl-2-imidazolidinone and an Alkanol at T = 298.15 K

Excess molar enthalpies, , and excess molar volumes, , of the mixtures {(1,3-dimethyl-2-imidazolidinone (DMI) + methanol, ethanol, 1-propanol, 2-propanol, or 1-butanol} for the whole range of compositions have been measured at T = 298.15 K. The excess molar enthalpy values ranged from a minimum of −410 J mol-1 for the mixture (DMI + methanol) to a maximum of +650 J mol-1 for the mixture (DMI + 2-propanol). The excess molar volumes are negative for all the mixtures studied and ranged from − 0.83 cm3 mol-1 to − 0.20 cm3 mol-1. The Redlich−Kister polynomial was used to correlate both the excess molar enthalpy and excess molar volume data. The NRTL and UNIQUAC models were used to correlate the enthalpy of mixing data. Both the NRTL and UNIQUAC models correlate the data equally well. The results are discussed in terms of the ease of hydrogen bond formation between the proton of the alkanol and the O atom of 1,3-dimethyl-2-imidazolidinone and are compared with related systems found in the literature.

Excess molar enthalpies and excess molar volumes of mixtures containingN-methyl-2-pyrrolidinone and an aromatic hydrocarbon atT = 298.15 K andp = 0.101325 MPa

Excess molar enthalpies and excess molar volumes at T= 298.15 K andp= 0.101325 MPa are reported for (N -methyl-2-pyrrolidinone + benzene, or methyl benzene, or 1,2-dimethyl benzene, or 1,3-dimethyl benzene, or 1,4-dimethyl benzene, or 1,3,5-trimethyl benzene, or ethyl benzene). The excess enthalpy ranges from a minimum of −546 J · mol−1for benzene to a maximum of 336 J · mol−1for 1,3,5-trimethyl benzene. The excess molar volumes are negative for all the mixtures. The Redlich–Kister equation was fitted to the data, and the ERAS model was used to correlate the data. The experimental results were interpreted in terms of associative and dissociative effects.

Excess Enthalpies and Volumes for Mixtures of (Acetonitrile + a Carboxylic Acid) at 298.15 K

Excess molar enthalpies and excess molar volumes for mixtures of (acetonitrile + acetic acid or propanoic acid or butanoic acid or 2-methylpropanoic acid or pentanoic acid or 3-methylbutanoic acid) at 298.15 K are presented. The excess molar enthalpy values are found to be positive for all six systems, whereas the excess molar volumes are found to be negative. The excess molar enthalpy values are correlated by the UNIQUAC and NRTL models and also by the Redlich Kister polynomial.

Excess Molar Volumes of Mixtures of Hexane + Natural Oils from 298.15 to 313.15 K

Excess molar volume data for mixtures containing hexane with three edible oils: olive, corn, and pip of grape have been determined from density measurements at various temperatures between 298.15 and 313.15 K using a vibrating tube densimeter. Results have been correlated by the Redlich−Kister equation. Systems showed negative deviations from ideality in the whole composition range.

Temperature dependence of the volumetric properties of binary mixtures containing oxaalkane + c-hexane

Excess molar volumes of mixtures of 2,5-dioxahexane + c-hexane, 2,5,8-trioxanonane + c-hexane, 2,5,8,11-tetraoxadodecane + c-hexane, and 2,5,8,11,14-pentaoxapentadecane + c-hexane were determined from density measurements at 283.15, 288.15, 298.15, and 308.15 K. These results allowed the following mixing quantities to be reported in the range of concentration: α, (δVE/δT)P, and (δHE/δP)T, at 298.15 K. The values obtained were then compared with the values calculated by using the Flory theory and the Nitta–Chao theory of liquid mixtures.

Correlation of Excess Molar Volumes of Mixtures by Means of PRSV Eos Coupled with Mixing Rule Containing Regular Solution and Residual Excess Free Energy (KTK).

Correlation of Excess Molar Volumes of Mixtures by Means of PRSV Eos Coupled with Mixing Rule Containing Regular Solution and Residual Excess Free Energy (KTK).

Temperature dependence of the volumetric properties of binary mixtures containing alcohols (1-propanol, 1-pentanol, 1-heptanol) + heptane

Excess molar volumes of mixtures of heptane + 1-propanol, 1-pentanol, or 1-heptanol were determined from density measurements at 278.15, 288.15, 298.15, and 308.15 K. From these results ([delta]V[sup E]/[delta]T)[sub P] and ([delta]H[sup E]/[delta]P)[sub T] at 298.15 K were calculated. The results were compared with the values calculated using the Nitta-Chao theory of liquid mixtures.

Temperature dependence of the volumetric properties of binary mixtures containing oxaalkane +n-heptane

Excess molar volumes of mixtures of n-heptane + 2,5-dioxahexane and n-heptane + 2,5,8-trioxanonane were determined from density measurentents at 5, 15, 25 and 35°C. These results allowed the following mixing quantities to be reported in all range of concentrations: α, (δvE/δT)P and (δhE/δP)T, at 25°C. The obtained values were then compared with the calculated values by using the Flory theory and the Nitta-Chao theory of liquid mixtures. The results are discussed in terms of order or disorder creation.

Excess molar enthalpies and excess molar volumes of mixtures of cycloalkanes and pseudo-cycloalkanes

Excess molar enthalpies and volumes were measured at atmospheric pressure and at 298.15 K for three-component systems. A pseudo-cycloalkane of carbon number m was mixed with a cycloalkane of carbon number m over the whole composition range. The values of m ranged from 6 to 8. The results were used to test the principle of congruence.