Solution Properties of Ternary D-Glucose + 1-Ethyl-3-methylimidazolium Ethyl Sulfate + Water Solutions at 298.15 K

The effect of an ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate ([EMIm]ESO₄), on the thermophysical properties of aqueous D-glucose solutions including density, viscosity, and electrical conductivity have been investigated at 298.15 K. Using these properties, the apparent molar volumes, V _φ , the viscosity B-coefficients and the molar conductivities, Λ _m, have been computed for the ternary D-glucose + [EMIm]ESO₄+water solutions. The V _φ values were used to calculate the standard partial molar volumes, V_f⁰V_{phi}^{0}, and transfer volumes, D_trV_f⁰Delta_{mathrm{tr}}V_{phi}^{0}, of D-glucose from water to aqueous ionic liquid solutions. These volumetric parameters, for all the solutions studied, are positive and increase monotonically with increasing the concentration of [EMIm]ESO₄. These observations have been interpreted in terms of the interactions between D-glucose and ionic liquid in the aqueous solution. The viscosity data were analyzed in terms of the Jones-Dole equation to determine the values of the viscosity B-coefficients. The calculated conductometric parameters, the limiting molar conductivities, Λ ₀, the association constants, K _a, and the Walden products, Λ ₀ η, for [EMIm]ESO₄, decrease with increasing concentration of D-glucose. This trend suggests that the ions of an ionic liquid do not have the same hydrodynamic size in the presence of D-glucose molecules (ILs) and consequently provides evidence for the dehydration effect of the ionic liquid in aqueous D-glucose solutions.     

Physical Properties of Binary Alcohol + Ionic Liquid Mixtures at Several Temperatures and Atmospheric Pressure

In this study, densities and speeds of sound were measured over the whole composition range, at T = (298.15, 303.15 and 308.15) K and p = 0.1 MPa, for the binary systems of ethanol, or 1-propanol, or 2-propanol and 1-butyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, or 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide. The density and speed of sound data were used to calculate the corresponding excess molar volumes and excess molar isentropic compressions, which were fitted with the Redlich–Kister equation. From the obtained results, a discussion was carried out in terms of interactions and structure factors in these binary mixtures.     

Physico-chemical Properties of Binary and Ternary Mixtures of Ethyl Acetate + Ethanol + 1-Butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide at 298.15 K and Atmospheric Pressure

Densities, viscosities and refractive indices have been measured at 298.15 K and atmospheric pressure for binary and ternary mixtures of ethanol, ethyl acetate and 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl) imide [C₄mim][NTF₂]. From these experimental properties, the corresponding excess properties have been calculated and adequately fitted with the Redlich-Kister polynomial equation. The adjustable parameters and standard deviations between experimental and calculated values are reported. Interest of this mixture is due to the possibility of using [C₄mim][NTF₂] as an entrainer in the extractive distillation of ethanol + ethyl acetate. These results are compared with previously determined experimental data for mixtures of ethyl acetate and/or ethanol with the ionic liquid 1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide, [C₈mim][NTF₂].     

Thermodynamic Properties of Binary Liquid Mixtures of n-Dodecane with an Alkan-1-ol or an Alkan-2-ol at 298.15 K: A Comparative Study

Experimental densities (ρ), viscosities (η), and speeds of sound (u) of the binary mixtures of n-dodecane with an alkan-1-ol (hexan-1-ol, heptan-1-ol, octan-1-ol) or an alkan-2-ol (hexan-2-ol, heptan-2-ol and octan-2-ol) were measured over the whole mixture composition range at T = 298.15 K. From these data, the excess molar volume ( $ V_{\text{m}}^{\text{E}} $ V m E ), deviations in viscosity (Δη), and excess isentropic compressibility ( $ \kappa_{S}^{\text{E}} $ κ S E ) have been calculated. The results were fitted by means of the Redlich–Kister equation, in order to estimate the binary coefficients and standard errors. Differences among these binary systems are ascribed to the different association abilities of the alkan-1-ols and alkan-2-ols. Experimental data on the constituted binaries were analyzed using McAllister’s multi-body interaction model, the Jouyban–Acree model, the Prigogine–Flory–Patterson theory, and the Bloomfield and Dewan model. The experimental and calculated quantities are used to study the nature of mixing behavior among the mixtures.     

Densities,Refractive Indices,Ultrasonic Speeds and Excess Properties of Acetonitrile + Poly(ethylene glycol) Binary Mixtures at Temperatures from 298.15 to 313.15 K

The densities, ρ, refractive indices, n _D, and ultrasonic speeds, u, of binary mixtures of acetonitrile (AN) with poly(ethylene glycol) 200 (PEG200), poly(ethylene glycol) 300 (PEG300) and poly(ethylene glycol) 400 (PEG400) were measured over the entire composition range at temperatures (298.15, 303.15, 308.15 and 313.15) K and at atmospheric pressure. From the experimental data, the excess molar volumes, \( V_{\text{m}}^{\text{E}} \) , deviations in refractive indices, \( \Delta n_{\text{D}} \) , excess molar isentropic compressibility, \( K_{{s , {\text{m}}}}^{\text{E}} \) , excess intermolecular free length, \( L_{\text{f}}^{\text{E}} \) , and excess acoustic impedance, Z ^E, have been evaluated. The partial molar volumes, \( \overline{V}_{\text{m,1}} \) and \( \overline{V}_{\text{m,2}} \) , partial molar isentropic compressibilities, \( \overline{K}_{{s , {\text{m,1}}}} \) and \( \overline{K}_{{s , {\text{m,2}}}} \) , and their excess values over whole composition range and at infinite dilution have also been calculated. The variations of these properties with composition and temperature are discussed in terms of intermolecular interactions in these mixtures. The results indicate the presence of specific interactions among the AN and PEG molecules, which follow the order PEG200 < PEG300 < PEG400.     

Excess Molar Volumes and Viscosities for Binary Mixtures of 1-Alkoxypropan-2-ols with 1-Butanol, and 2-Butanol at 298.15 K and Atmospheric Pressure

Excess molar volumes Vm^E and kinematic viscosities v have been measured as a function of composition for binary mixtures of propylene glycol monomethyl ether （1-methoxy-2-propanol）, MeOCH2CH（OH）Me, propylene glycol monoethyl ether （1-ethoxy-2-propanol）, EtOCH2CH（OH）Me, propylene glycol monopropyl ether （1-propoxy-2-propanol）, PrOCH2CH（OH）Me, propylene glycol monobutyl ether （1-butoxy-2-propanol）, BuOCH2CH（OH）Me, and propylene glycol tert-butyl ether （1-tert-butoxy-2-propanol）, t-BuOCH2CH（OH）Me with 1-butanol, and 2-butanol, at 298.15 K and atmospheric pressure. The excess molar volumes are negative across the entire range of composition for all the systems with 1-butanol, and positive for the systems 2-butanol＋ 1-methoxy-2-propanol, and ＋1-propoxy-2-propanol, negative for the systems 2-butanol＋1-butoxy-2-propanol, and change sign for the systems 2-butanol＋ 1-ethoxy-2-propanol, and ＋ 1-tert-butoxy-2-propanol. From the experimental data, the deviation in dynamic viscosity η from ∑χiηi has been calculated. Both excess molar volumes and viscosity deviations have been correlated using a Redlich-Kister type polynomial equation by the method of least-squares for the estimation of the binary coefficients and the standard errors.     

Measurements of the Molar Heat Capacities and Excess Molar Heat Capacities for Water + Organic Solvents Mixtures at 288.15 K to 303.15 K and Atmospheric Pressure

Experimental molar heat capacity data (Cp _m) and excess molar heat capacity data (Cp^E_m\mathit{Cp}^{\mathrm{E}}_{\mathrm{m}}) of binary mixtures containing water + (formamide or N,N-dimethylformamide or dimethylsulfoxide or N,N-dimethylacetamide or 1,4-dioxane) at several compositions, in the temperature range 288.15 K to 303.15 K and atmospheric pressure, have been determined using a modified 1455 PAAR solution calorimeter. The excess heat capacities are positive for aqueous solutions containing 1,4-dioxane, N,N-dimethylformamide or dimethylsulfoxide, negative for solutions containing water + formamide and show a sigmoid behavior for mixtures containing water + N,N-dimethylacetamide, over the whole composition range. The experimental excess molar heat capacities are discussed in terms of the influence of temperature and of the organic solvent type present in the binary aqueous mixtures, as well as in terms of the existing molecular interactions and the organic solvent’s molecular size and structure.     

The Relative Reduced Redlich–Kister Equations for Correlating Excess Properties of N,N-Dimethylacetamide + Water Binary Mixtures at Temperatures from 298.15 K to 318.15 K

Excess molar volumes, viscosity deviations, and isentropic compressibility changes in N,N-dimethylacetamide + water binary mixtures at (298.15, 308.15 and 318.15)?K were calculated from experimental density, viscosity and sound velocity results presented in previous work. Here these experimental values were used to test the applicability of the correlative reduced Redlich?CKister equation and the recently proposed Herráez equation, as well as their corresponding relative functions. Their correlation ability at different temperatures, and the use of different numbers of parameters, are discussed for the case of limited experimental data. The relative functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Values of the limiting excess partial molar volume at infinite dilution were deduced using different methods. Also, the activation parameters and partial molar Gibbs energy of activation of viscous flow were analyzed as functions of composition. Correlation between the two Arrhenius parameters of viscosity in all composition domains show the existence of two distinct behaviors, separated by a stabilized structure over a short range of mole fractions from (0.2?to?0.3) in N,N-dimethylacetamide. In this regard, a correlation equation recently proposed by Belda has also been applied to the present system for deriving molar volume properties, in order to assess the validity of the proposed equation,     

Quaternary Liquid–Liquid Equilibria for Fuel Additive Systems Containing Diethyl Carbonate or 1,1-Dimethylethyl Methyl Ether at 298.15 K and Atmospheric Pressure

Liquid–liquid equilibrium tie line data were determined for three quaternary systems water + ethanol + diethyl carbonate+n-heptane, water + ethanol + 1,1-dimethylethyl methyl ether + diethyl carbonate, and water + 1,1-dimethylethyl methyl ether + diethyl carbonate+n-heptane at 298.15 K and atmospheric pressure. The experimental liquid–liquid equilibria results have been correlated using a modified UNIQUAC model and an extended UNIQUAC model, both with multicomponent interaction parameters in addition to the binary ones.     

Investigations of Molecular Interactions in the Binary Mixtures of 1-Butyl-3-methylimidazolium bis(Trifluoromethanesulfonyl) Amide and 2-Propoxyethanol from <Emphasis Type="Italic">T</Emphasis> = (298.15 to 323.15) K at Atmospheric Pressure

Density and speed of sound values of pure and binary mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide ([Bmim][NTf₂]) and 2-propoxyethanol (2-PR) were determined over the whole composition range as a function of temperature from 298.15 to 323.15 K) under atmospheric pressure. Heat capacity values of the pure compounds were also measured. The experimental values were used to calculate excess molar volume, excess isentropic compressibility, excess intermolecular free length and excess speed of sound values. The excess values were fitted with the Redlich–Kister polynomial equation to estimate the binary coefficients and standard deviation between the experimental and calculated values. The partial molar volumes at infinite dilutions were also calculated. The trends of variation of these properties were interpreted in light of the solute–solvent interactions occurring in the system. Further, the molecular interactions in the binary system were analyzed using experimental FT-IR spectra recorded at room temperature.     

The Relative Reduced Redlich–Kister and Herráez Equations for Correlating Excess Properties of N,N-Dimethylacetamide + Formamide Binary Mixtures at Temperatures from 298.15 K to 318.15 K

Excess molar volumes and viscosity deviations in binary mixtures of N,N-dimethylacetamide with formamide at (298.15, 308.15 and 318.15) K were calculated from experimental density and viscosity data presented in previous work. The density and viscosity data as well as their corresponding derived functions were used to test the applicability of two correlative equations: the reduced Redlich?CKister equation and the recently proposed Herráez equation. Their correlation abilities at different temperatures, and the use of different numbers of parameters, are discussed for the case of limiting experimental data. These relative functions are important to reduce the effect of temperature and, consequently, to reveal the effects of different types of interactions. Correlation between the two Arrhenius parameters of viscosity over the composition domains shows the existence of two distinct behaviors.     

Solute–Solvent Interactions of Amino Acids in Aqueous 1-Propyl-3-Methylimidazolium Bromide Ionic Liquid Solutions at 298.15 K

Densities, viscosities, and refractive indices of three amino acids (glycine, L-alanine, and L-valine) in aqueous solutions of an ionic liquid, 1-propyl-3-methylimidazolium bromide, have been measured at 298.15 K. These data have been used to calculate apparent molar volumes (V _φ ), viscosity B-coefficients, and molar refractions of these mixtures. The standard partial molar volumes (V_f⁰V_{\phi}^{0}) and standard partial molar volumes of transfer (D_trV_f⁰\Delta_{\mathrm{tr}}V_{\phi}^{0}) have been determined for these amino acid solutions from these density data. The resulting values of V_f⁰V_{\phi}^{0} and D_trV_f⁰\Delta_{\mathrm{tr}}V_{\phi}^{0} for transfer of amino acids from water to aqueous ionic liquid solutions have been interpreted in terms of solute + solvent interactions. These data also indicate that hydrophobic interactions predominate in L-alanine and L-valine solutions. Linear correlations were found for both V_f⁰V_{\phi}^{0} and the viscosity B-coefficient with the number of carbon atoms in the alkyl chain of the amino acids, and have been used to estimate the contribution of the charged end groups (NH₃⁺\mathrm{NH}_{3}^{+}, COO⁻), the CH₂ group, and other alkyl chains of the amino acids. The viscosity and molar refractivity results have been used to confirm the conclusions obtained from volumetric properties.     

Studies of some Thermodynamic Properties of Binary Mixtures of Acrylonitrile with Aromatic Ketones at <Emphasis Type="Italic">T</Emphasis>=308.15 K

Densities (ρ), ultrasonic speeds (u), and excess molar volumes (V_m^EV_{\mathrm{m}}^{\mathrm{E}}) of binary mixtures of some aromatic ketones in acrylonitrile have been measured over the entire range of composition at 308.15 K. From these experimental results, parameters such as the isentropic compressibilities K _S , interaction parameter χ ₁₂, Flory parameters, A _i coefficients, standard deviations σ(Y ^E), and molar sound velocities R _m have been estimated. The excess functions were fitted to Redlich-Kister type polynomial equations. The experimental ultrasonic speeds were analyzed in terms of Jacobson’s Free Length Theory (FLT), Schaaff’s Collision Factor Theory (CFT), Nomoto’s relation, and Van Dael’s ideal mixture relation. The intermolecular Free Length L _f, and available volume V _a, have been calculated from the FLT, CFT, and thermoacoustic approaches for binary systems of acetophenone and propiophenone in acrylonitrile at 308.15 K.     

Measurement and Correlation of Excess Molar Enthalpy of Binary Mixtures Containing Butyl Acetate + 1-Alkanols (C1–C6) at 298.15 K

Excess molar enthalpies, ?H _m ^E , for the binary mixtures of butyl acetate + 1-alkanols, namely (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, and 1-hexanol), were measured over the whole range of composition at 298.15 K using a Parr 1455 solution calorimeter. The excess partial molar enthalpies, ?H _m,i ^E , were calculated from the experimental excess molar enthalpies using the Redlich–Kister polynomial equation. The sign of ?H _m ^E for all systems are positive because of the disruption of hydrogen bonding and dipole–dipole interactions in the alkanols and esters, respectively. The magnitude of the ?H _m ^E values increases with increasing alkyl chain length. The behavior of ?H _m ^E was analyzed in terms of the length of the alkanol chain, the nature and type of intermolecular interactions and the balance between positive and negative effects on deviations from ideality. The experimental excess molar enthalpy data have also been correlated using the Redlich–Kister and SSF equations and two local composition models (UNIQUAC and NRTL).     

Volumetric Properties of Aqueous Solutions of Tetramethyl-<Emphasis Type="Italic">bis</Emphasis>-urea between 278.15 and 338.15 K at Atmospheric Pressure

Densities of aqueous solutions of tetramethyl-bis-urea (TMbU) with solute mole fractions ranging up to 7.0×10⁻² have been measured with an uncertainty of 1.5×10⁻⁵ g⋅cm⁻³, at 278.15, 298.15, 318.15, and 338.15 K using a vibrating-tube densimeter. The partial molar volumes and expansibilities of TMbU (down to the infinite dilution) and water have been computed. The effects of solute concentration and temperature on the volume packing changes, caused by dissolution (and hydration) of TMbU in an aqueous medium, have been considered.     

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 V ^E 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 V ^E values. For mixtures with open chain alkanes, V ^E increases from C5 to C7 and then decreases. A similar trend is shown by mixtures with cycloalkanes. V ^E values are compared with known H ^E data for mixtures with heptane and tetrachloromethane. Signs and trends of V ^E and H ^E 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.