Excess Molar Volumes VE Research Articles

Thermodynamic and Spectroscopic Study of the Ternary System Dimethyladipate + Tetrahydrofuran +1-Butanol at T = (288.15 to 323.15) K

Experimental densities ρ, refractive indices nD, and viscosity η data of the ternary dimethyladipate + tetrahydrofuran + 1-butanol and the binary tetrahydrofuran + 1-butanol systems have been determined, while viscosities have been measured for the binary dimethyladipate + 1-butanol system. The properties ρ, nD, and η are experimentally determined at eight temperatures over the temperature range T = (288.15 to 323.15) K and at atmospheric pressure, using instruments from Anton Paar: digital vibrating tube densimeter DMA 5000, refractometer RXA 156, and SVM 3000/G2 digital Stabinger viscometer. Excess molar volumes VE, deviations of refractive indices ΔnD, and deviations of viscosities Δη were calculated from the measured data. The Redlich–Kister equation is used to correlate excess molar volumes, deviations of refractive indices, and viscosities for binary mixtures, while the Nagata–Tamura equation is applied for a ternary mixture. FT-IR studies of the binary constituents of the investigated ternary mixtu...

Effects of water on the properties of acetamide-KSCN eutectic ionic liquids at several temperatures

The effects of water on the density, conductivity and viscosity of acetamide-KSCN eutectic ionic liquid were investigated at atmospheric pressure and temperatures from 303.15 to 343.15K. The density and viscosity values decrease monotonically when the water is added and the data decrease with increasing temperature. From the experimental values, the molecular volume Vm, excess molar volumes VE and viscosity deviation Δη of acetamide-KSCN (3:1) aqueous solutions were calculated. The excess molar volumes VE and viscosity deviation Δη were both well fitted by a Redlich–Kister equation. The conductivity of the solutions increases gradually first and then decreases dramatically with increasing mole fraction of water. The mass fraction of water dependence of electrical conductivity was fitted by a line equation at salt-rich region. The speculated interactions of eutectic ionic liquid with water account for the changes of physiochemical properties.

The Effect of the Molecular Size and Shape on the Volume Behavior of Binary Liquid Mixtures. Branched and Cyclic Alkanes in Heptane at 298.15 K

Excess molar volumes VE for 40 mixtures of heptane with a liquid alkane and apparent molar volumes in heptane for eight solid alkanes have been obtained at 298.15 K. They include five linear, 30 branched-chain, and 13 cyclic alkanes. Almost all systems exhibit negative VE values. For mixtures with open chain alkanes, VE increases from C5 to C7 and then decreases. A similar trend is shown by mixtures with cycloalkanes. VE values are compared with known HE data for mixtures with heptane and tetrachloromethane. Signs and trends of VE and HE are correlated with the free volume and interactional terms of the Flory theory. The partial molar volumes at infinite dilution in heptane, V°, have also been obtained and discussed together with literature data on other hydrocarbons and polar compounds. The calculated contributions to V° by CH3, CH2, CH and C groups are compared with previously determined contributions of polar groups. The lower contributions of the latter groups are explained with the volume contraction caused by dipole-induced dipole interaction. The volume effects associated with branching and cyclization have been evaluated and compared with the corresponding effects on solvation enthalpy. The branching effect, in the order of magnitude of few cm3·mol−1, and the larger negative values of cyclization volumes, down to −24 cm3·mol−1, are discussed in terms of packing and solute–solvent interactions, in analogy to polar organic solutes either in heptane and tetrachloromethane. A negative cyclization effect is also exhibited by the solvation enthalpies.

Density and Viscosity for Binary Mixtures of Diethylene Glycol Monobutyl Ether with Monoethanolamine, Diethanolamine, and Triethanolamine from (293.15 to 333.15) K

Density and viscosity for binary mixtures of diethylene glycol monobutyl ether (DEGMBE) with monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) have been measured as a function of composition from (293.15 to 333.15) K at intervals of 10 K under ambient pressure. Densities were measured with a capillary pycnometer. Viscosities were determined using capillary viscometers of the Ubbelohde type. Excess molar volumes VE and viscosity deviations Δη were calculated from the experimental results and correlated by the Redlich–Kister type equations to derive the coefficients and standard deviations. The values of VE and Δη are both negative over the entire range of mole fraction which indicates that molecular interaction of MEA, DEA, and TEA through the hydrogen bond become weaker in the presence of DEGMBE.

Thermodynamic and Acoustic Study on Molecular Interactions in Certain Binary Liquid Systems Involving Ethyl Benzoate

Speeds of sound and density for binary mixtures of ethyl benzoate (EB) with N,N-dimethylformamide (NNDMF), N,N-dimethyl acetamide (NNDMAc), and N,N-dimethylaniline (NNDMA) were measured as a function of mole fraction at temperatures 303.15, 308.15 K, 313.15 K, and 318.15 K and atmospheric pressure. From the experimental data, adiabatic compressibility (βad), intermolecular free length (Lf), and molar volume (V) have been computed. The excess values of the above parameters were also evaluated and discussed in light of molecular interactions. Deviation in adiabatic compressibilities and excess intermolecular free length (LfE) are found to be negative over the molefraction of ethyl benzoate indicating the presence of strong interactions between the molecules. The negative excess molar volume VE values are attributed to strong dipole-dipole interactions between unlike molecules in the mixtures. The binary data of Δβad, VE, and LfE were correlated as a function of molefraction by using the Redlich-Kister equation.

Excess Molar Volumes, Excess Molar Enthalpies and Excess Isentropic Compressibilities of 1-Methyl Pyrrolidin-2-one with Water and Propanols

Excess molar volumes V E, excess molar enthalpies H E, and speeds of sound u for 1-methyl pyrrolidin-2-one (1) + water or propan-1-ol or propan-2-ol (2) binary mixtures have been measured over the entire composition range (at 308.15 K) using a dilatometer, calorimeter and interferometer. Speeds of sound data, u, of (1 + 2) binary mixtures have been utilized to determine excess isentropic compressibilities, $$ \kappa_{S}^{\text{E}} $$ . The observed V E, H E and $$ \kappa_{S}^{\text{E}} $$ data have been analyzed in terms of (1) Graph theory (which involves the topology of the constituents of mixture), and (2) the Prigogine–Flory–Patterson theory. Analysis of V E data in terms of Graph theory suggests that 1-methyl pyrrolidin-2-one, water, propan-1-ol, and propan-2-ol exist as associated molecular entities. IR studies lend additional support to the proposed molecular entities in (1 + 2) mixtures. It has been observed that V E, H E and $$ \kappa_{S}^{\text{E}} $$ values predicted by Graph theory compare well with their corresponding experimental values.

Density, conductivity, viscosity, and excess properties of (pyrrolidinium nitrate-based Protic Ionic Liquid + propylene carbonate) binary mixture

Density, ρ, viscosity, η, and conductivity, σ, measurements of binary mixtures containing the pyrrolidinium nitrate Protic Ionic Liquid (PIL) and propylene carbonate (PC), are determined at the atmospheric pressure as a function of the temperature from (283.15 to 353.15)K and within the whole composition range. The temperature dependence of both the viscosity and conductivity of each mixture exhibits a non-Arrhenius behaviour, but is correctly fitted by using the Vogel–Tamman–Fulcher (VTF) equation. In each case, the best-fit parameters, such as the pseudo activation energy, Ea∗ and ideal glass transition temperature, T0 are then extracted. The excess molar volumes VE, and viscosity deviations from the ideality, Δη, of each investigated mixture were then deduced from the experimental results, as well as, their apparent molar volumes, Vϕ, thermal expansion coefficients αp, and excess Gibbs free energies (ΔG∗E) of activation of viscous flow. The VE, αpE, Δη values are negative over the whole composition range for each studied temperature therein. According to the Walden rule, the ionicity of each mixture was then evaluated as a function of the temperature from (283.15 to 353.15)K and of the composition. Results have been then discussed in terms of molecular interactions and molecular structures in this binary mixture.

Properties of pure n-butylammonium nitrate ionic liquid and its binary mixtures of with alcohols at T = (293.15 to 313.15) K

Values of the density and viscosity of the pure ionic liquid n-butylammonium nitrate (N4NO3) and its binary mixtures with methanol, ethanol, 1-propanol, and 1-butanol were measured at temperature ranging from T=(293.15 to 313.15)K. The thermal expansion coefficient, molecular volume, standard entropy, and lattice energy of N4NO3 were deduced from the experimental density results. The temperature dependence of the viscosity of N4NO3 was fitted to the fluidity equation. Excess molar volumes VE and viscosity deviations Δη for the binary mixtures were calculated and fitted to the Redlich–Kister equation with satisfactory results. Both excess molar volumes and viscosity deviations show negative deviations for (N4NO3+alcohol) mixtures. The effect of the temperature and the size of the alcohol on the excess molar volumes and viscosity deviations are discussed and analysed. Other derived properties, such as the apparent molar volume, partial molar volume, excess partial molar volume, thermal expansion coefficient, and excess thermal expansion coefficient of the above-mentioned systems were also calculated.

The variation of viscosity, refractive indices, compressibility, intermolecular free length, and excess molar volume of the acetophenone—ethyl acetate solutions at 303.15–323.15 K

Densities, viscosities, refractive indices and ultrasonic velocities of the binary mixtures of acetophenone with ethyl acetate were measured over the entire mole fractions at 303.15, 313.15, and 323.15 K. From the experimental results, excess molar volumes VE, viscosity deviation Δη, refractive index deviation ΔnD, deviations in isentropic compressibility Δκs and excess intermolecular free length ΔLf are calculated. The viscosity values were fitted to the models of Krishnan-Laddha and McAllister. The thermophysical properties under study were fit to the Jouyban-Acree model. The excess values were correlated using Redlich-Kister polynomial equation to obtain their coefficients and standard deviations. The data obtained fitted with the values correlated by the corresponding models very well. The results are interpreted in terms of molecular interactions occurring in the solution.

Thermophysical properties of 1-hexyl-3-methylimidazolium tetrafluoroborate [hmim][BF4] + N-methyldiethanolamine (MDEA) at temperatures (303.15 to 323.15) K

Binary mixtures of 1-hexyl-3-methylimidazolium tetrafluoroborate [hmim][BF4] with N-methyldiethanolamine (MDEA) were prepared. Physical properties namely, density ρ, dynamic viscosity η and refractive index nD, of the binary mixtures were measured over a temperature range of 303.15K to 323.15K. The measured density and refractive index data were correlated as a function of concentration and temperature. Excess molar volumes VE were deduced from the experimental data. Excess molar volumes showed positive deviations over the entire range of concentrations and temperatures indicating a weak interaction between [hmim][BF4] and MDEA. Viscosity data for the binary mixtures were correlated by using the Kendall–Monroe model.

Measurements and Correlations of the Isobaric Vapor–Liquid Equilibria of Binary Mixtures and Excess Properties for Mixtures Containing an Alkyl (Methyl, Ethyl) Butanoate with an Alkane (Heptane, Nonane) at 101.3 kPa

In this work, the measurements of the isobaric vapor–liquid equilibrium (VLE) data at 101.32 kPa and the excess molar volumes (vE), obtained at 10 K intervals of temperature in the range (288.15 to 328.15) K, for four binary systems comprised of methyl or ethyl butanoate with two alkanes (heptane and nonane) are presented. The vE are positive for the four mixtures, and their variation with temperature presents a thermal coefficient (∂vE/∂T)p > 0, and the behavior of these systems is interpreted. Experimental VLE data (p,T,x,y), obtained in a small capacity ebulliometer, present a positive consistency according to the method of Fredenslund. The methyl butanoate + heptane system presents a minimum boiling-temperature azeotrope with the following coordinates at the working pressure: (x1,az = 0.404; Taz = 367.65 K). Measurements of (T,pio) are also shown for all of the compounds and were determined using the same equilibrium equipment. Experimental data are correlated with an appropriate polynomial model prop...

Effect of β-cyclodextrin on the behaviour of thermophysical and spectroscopic properties of binary mixtures of (isomeric butanediol + pyrrolidin-2-one)

Thermophysical parameters viz. excess molar volume VE, speed of sound u, viscosity η and spectroscopic parameters viz. FT-IR, 1H and 13C NMR have been measured for the ternary liquid mixtures of {isomeric butanediol (butane-1,2-diol, butane-1,3-diol, butane-1,4-diol, butane-2,3-diol)+pyrrolidin-2-one} in β-cyclodextrin over the whole composition range at T=308.15K. The deviation in the isentropic compressibility ΔκS, partial molar quantities QiE, deviation in viscosity Δη, deviation in Gibbs energy of activation for viscous flow g(x) and excess NMR chemical shift δE have been estimated and analysed. Results indicate that the position of hydroxyl groups of butanediol showed a noticeable effect on the thermophysical properties. Furthermore, the effect of addition of β-cyclodextrin caused significant changes, due to difference in the fitting of isomeric butanediol in the hydrophobic cavity of β-cyclodextrin. Particularly, visible changes in thermophysical properties of 1,4-BTD system have been observed in comparison to other isomers of BTD indicating that hydrogen bonding and affinity of fitting between (1,4-BTD and β-CD+PY) are greater than the other isomers. These results have been found to be in excellent concurrence with NMR and FT-IR studies. However, for 2,3-BTD and 1,3-BTD systems dispersion forces due to dissociation of self-associated PY and diols are predominant. The spectroscopic measurements (FT-IR, 1H and 13C NMR) confirm that the interaction between unlike molecules take place through hydroxyl groups of isomeric butanediol and carbonyl group of pyrrolidin-2-one.

Density and Viscosity of Binary Mixtures of n-Butyl Acetate with Ketones at (298.15, 303.15, 308.15, and 313.15) K

Densities and viscosities of binary mixtures of n-butyl acetate with acetophenone, cyclopentanone, cyclohexanone, and 3-pentanone were determined over the entire composition range at temperatures (298.15 to 313.15) K and at normal atmospheric pressure. From the experimental data, the excess molar volumes VE and excess free energy of activation of viscous flow ΔG*E were calculated. These results were fitted to the Redlich–Kister polynomial equation. The excess molar volumes for all of the studied systems are negative over the whole composition range and at all of the studied temperatures. The experimental mixture viscosity data have been correlated using Grunberg–Nissan, Heric (two-parameter), and McAllister (four-body) models at different temperatures.

Measurements and correlations of viscosity, conductivity and density of an hydrophobic ionic liquid (Aliquat 336) mixtures with a non-associated dipolar aprotic solvent (DMC)

Ionic liquid “Aliquat 336”, a promising electrolyte for electrochemical devices, was investigated. The transport physicochemical properties of binary mixture ionic liquid (Aliquat 336)/organic solvent (DMC) were studied. Systematical measurements of viscosities (η), conductivities (Λ) and densities (ρ) for the binary mixture, over the whole composition range and at temperature ranging from 298.15K to 318.15K, were performed. The variation tendency of viscosities/conductivities with composition of the mixtures was explained through the disruption of molecular solutes to ionic association or aggregation. Correlation between these two parameters was carried out by means of Walden product (W). A semi-empirical equation proposed by Jones and Dole was used to describe the variation of viscosity with salt concentration (C). At low concentration of Aliquat 336, molar conductivity follows the cube root law which was predicted by the quasilattice model. The two transport processes were well described by Arrhenius law. From this later, the activation energies for the viscosity (Ea,η) and conductivity (Ea,Λ) are deduced. Molecular interactions and structures of binary mixtures have been discussed from the excess molar volumes VE.

Thermophysical and spectroscopic studies of room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate in Tritons

The thermophysical properties viz. density ρ, speed of sound u, and specific conductivity κ of pure room temperature ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and its binary formulations with Triton X-45 and Triton X-100 have been studied over the entire composition range at different temperatures (293.15 to 323.15)K. Excess molar volume VE, deviation in isentropic compressibility ΔKS, partial molar excess volume ViE, deviation in partial molar isentropic compressibility ΔKS,i, deviation in specific conductivity Δκ have also been estimated and analysed. Spectroscopic properties (IR, 1H and 13C NMR) of these mixtures have been investigated in order to understand the structural and interactional behaviour of formulations studied. The magnitude of interactions between the two components increases with addition of number of oxyethylene groups in Tritons and with rise in temperature. Spectroscopic measurements indicate that interactions are mainly taking place through the five member ring of room temperature ionic liquid and six member ring of Tritons.

Properties of pure 1-methylimidazolium acetate ionic liquid and its binary mixtures with alcohols

Densities and viscosities of the pure ionic liquid 1-methylimidazolium acetate ([Mim]Ac) and its binary mixtures with methanol, ethanol, 1-propanol, and 1-butanol were measured at temperature ranging from T=(293.15 to 313.15)K. The thermal expansion coefficient, molecular volume, standard entropy, and lattice energy of [Mim]Ac were deduced from the experimental density results. A simple linear equation was used to correlate the variation of viscosity of [Mim]Ac with temperature. Excess molar volumes VE and viscosity deviations Δη for the binary mixtures at above mentioned temperature were calculated and fitted to the Redlich–Kister equation with satisfactory results. Excess molar volumes for {[Mim]Ac+1-butanol} mixture have an S shape, while those for other mixtures have a negative deviation from ideal behaviour over the entire mole fraction range. Viscosity deviations are all negative deviation for {[Mim]Ac+alcohol} mixtures. The results were interpreted in terms of interactions and structural factors of binary mixtures.

Density, Viscosity, and Refractive Index Properties for the Binary Mixtures of n-Butylammonium Acetate Ionic Liquid + Alkanols at Several Temperatures

Densities and viscosities were determined for the binary mixtures of n-butylammonium acetate ionic liquid (N4AC) with methanol, ethanol, n-propanol, and n-butanol at temperatures of (293.15, 298.15, 303.15, 308.15, and 313.15) K under atmospheric pressure. The refractive indices of the above-mentioned binary mixtures were measured at 298.15 K. Excess molar volumes VE, viscosity deviations Δη, and refractive index deviations ΔnD were obtained from the experimental data and fitted with the Redlich–Kister equation. The correlation results were in good agreement with the experimental data, and optimal fitting parameters were presented. The results were interpreted in terms of interactions and structural factors of N4AC + alkanols mixtures.

Densities, Viscosities, Refractive Indices and Sound Speeds of Acetophenone with Methylacetate at Different Temperatures

Densities, viscosities, refractive indices and ultrasonic velocities of the binary mixtures of Acetophenone with Methyl acetate were measured over the entire mole fractions at (303.15, 313.15 and 323.15) K. From these experimental results, excess molar volumes VE, viscosity deviation ∆η, refractive index deviation ∆nD, deviations in isentropic compressibility ∆Ks and excess intermolecular free length ∆Lf are calculated. The viscosity values were fitted to the models of Krishnan‐Laddha and McAllister. The thermo physical properties under study were fit to the Jouyban ‐ Acree model. The excess values were correlated using Redlich‐Kister polynomial equation to obtain their coefficients and standard deviations. It was found that in all cases, the data obtained fitted with the values correlated by the corresponding models very well. The results are interpreted in terms of molecular interactions occurring in the solution.

Thermodynamic Study of Heptane + Silicone Mixtures. Excess Volumes and Enthalpies at 298.15 K

Excess molar volumes VE and partial molar enthalpies and excess enthalpies HE of binary mixtures of heptane + linear (hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, dodecamet...

Densities, Viscosities, Speeds of Sound, FT-IR and 1H-NMR Studies of Binary Mixtures of n-Butyl Acetate with Ethanol, Propan-1-ol, Butan-1-ol and Pentan-1-ol at 298.15, 303.15, 308.15 and 313.15 K

Densities, viscosities and speeds of sound of binary mixtures of ethanol, propan-1-ol, butan-1-ol and pentane-1-ol with n-butyl acetate have been measured over the entire range of composition at temperatures of 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure. From the experimental densities, viscosities and speeds of sound, the excess molar volumes V E, deviations in viscosity Δη, and deviations in isentropic compressibility Δκ S have been calculated. The excess molar volumes and deviations in isentropic compressibility are positive for all the binary systems studied over the whole composition, while deviations in viscosities are negative for all of the binary mixtures. The excess molar volumes, deviations in viscosity, and deviations in isentropic compressibility have been fitted to a Redlich–Kister type polynomial equation. FTIR and 1H-NMR studies of these mixtures are also reported.