Showing papers in "Physics and Chemistry of Liquids in 1998"
TL;DR: In this article, a simple formalism is provided to relate the viscosity and the chemical diffusion coefficient of binary liquid alloys, which reduces to the form of Stokes-Einstein relation.
Abstract: A simple formalism is provided to relate the viscosity and the chemical diffusion coefficient of binary liquid alloys. Only under simplified considerations, it reduces to the form of Stokes-Einstein relation. The positive and negative deviations of the viscosity from the additive rule of mixing have been ascribed to the role of energetic and size effects.
57 citations
TL;DR: In this article, the density and refractive indices for mixtures of dimethylsulfoxide (DMSO) with N-dimethylformamide were measured over the whole composition range at 298.15 K, as well as the relative permittivities at 288.15k, 293.15K, 298,15 K and 303,15k.
Abstract: Density and refractive indices for mixtures of dimethylsulfoxide (DMSO) with N.N-dimethylformamide were measured over the whole composition range at 298.15 K, as well as the relative permittivities at 288.15 K, 293.15 K, 298,15 K, 303,15 K and 308.15K. From these data the excess molar volumes, apparent and partial molar volumes of DMSO and DMF, the excess relative permittivity, the temperature coefficients of relative permittivity and Kirkwood's correlation factor for investigated mixtures were calculated. The 1H-NMR spectra of these liquid binary mixtures, were recorded at 298 K and the spectral parameters, Δδ(DMSO - DMF) were calculated. These structural parameters as functions of concentration suggest the formation of the most stable “complexes” of the 2 DMSO•DMF and DMSO•DMF types.
38 citations
TL;DR: In this paper, the authors measured the speeds of sound, densities and refractive indices of binary mixtures containing acetone, methanol, ethanol, or 2-butanone at 298.15 K and atmospheric pressure, in the whole composition diagram, the derived excess values being determined.
Abstract: Speeds of sound, densities and refractive indices of the binary mixtures containing acetone, methanol, ethanol, or 2-butanone have been measured at 298.15 K and atmospheric pressure, in the whole composition diagram, the derived excess values being determined. Parameters of analytical expressions which represent the composition dependences of excess and variation of properties are reported. Values of physical properties were compared with the results obtained by different prediction methods. The excess volumes were estimated using different applications of the Heller equation, which are depending on the refractive indices of the mixtures. A good agreement between the experimental and theoretical values both in magnitude and sign were obtained by these methods.
36 citations
TL;DR: In this paper, the density data of aqueous solutions of 1-propanol, 2-pro panol, allyl alcohol and propargyl alcohol at temperatures ranging from 30°-50°C were analyzed.
Abstract: Excess molar volumes, VE have been claculated from the density data of aqueous solutions of 1-propanol, 2-propanol, allyl alcohol and propargyl alcohol at temperatures ranging from 30°-50°C. The VE values have been found to be negative at all temperatures. The volume contraction for saturated alcohols, both straight and branched chain, in aqueous media is accounted for mainly by the hydrophobic effect, while that for unsaturated alcohols is explained primarily by the formation of H-bond between the alcohol and water. The dVE/dT values have been found to be positive for all alcohols. The temperature dependence of VE is thought to be strongly influenced by the structural properties of water.
36 citations
TL;DR: In this paper, the saturation mole fraction of thioxanthen-9-one dissolved in thirty-five different organic nonelectrolyte solvents containing ester-, ether-, hydroxy-, methyl- and t-butyl functional groups was measured at 25.0°C.
Abstract: Experimental solubilities are reported at 25.0°C for thioxanthen-9-one dissolved in thirty-five different organic nonelectrolyte solvents containing ester-, ether-, hydroxy-, methyl- and t-butyl-functional groups. Results of these measurements are used to test the applications and limitations of expressions derived from Mobile Order theory. For the 26 solvents for which predictions could be made computations show that Mobile Order theory does provide fairly reasonable (although by no means perfect) estimates of the saturation mole fraction solubilities. Average absolute deviation between predicted and observed values is circa 45%. In comparison, the average absolute deviation increases significantly to 420% when ideal solution behavior is assumed.
34 citations
TL;DR: In this article, the apparent molar volumes of amino acids at very low molality were determined from density measurements, and it was shown that the concentration dependence of these amino acids in very low mollality differs from the behavior found at concentrations higher than 0,01m.
Abstract: The apparent molar volumes of DL–α–alanine, DL–β–alanine, DL–α–aminobutyric acid, DL–α–phenylalanine, DL–serine and DL–aspartic acid in very dilute aqueous solutions at 25,00°C were determined from density measurements. From these data it is shown that the concentration dependence of the apparent molar volume of these amino acids at very low molality differs from the behavior found at concentrations higher than 0,01m. This change has been attributed to solute-water interactions which prevail at very high dilution.
22 citations
TL;DR: In this article, the 1 H-NMR spectra of liquid binary mixtures, acetonitryle (ACN) - water (H 2 O), were recorded at 298 K and the spectral parameters, Δδ(ACN-H 2O) were evaluated.
Abstract: The 1 H-NMR spectra of liquid binary mixtures, acetonitryle (ACN) - water (H 2 O), were recorded at 298 K and the spectral parameters, Δδ(ACN-H 2 O) were evaluated. The surface tensions (σ 12 ) were measured at 298.15 K. From literature values of density (d 12 ), viscosity (η 12 ), relative permittivities (e 12 ) and measured surface tensions the values of molar volumes (V 12 ) and their deviations from ideality were calculated. Further on the temperature coefficients of relative permittivity, α 12 =(1/e 12 ).[de 12 /d(1/7)], were evaluated. These structural parameters as functions of concentration suggest the formation of the intermolecular complexes of the ACN. 2H 2 O, ACN. H 2 O, 2 ACN. 3H 2 O and 2 ACN. 3 H 2 O types.
16 citations
TL;DR: In this article, the dielectric constants of some aqueous-organic solvent mixtures have been analyzed by an equation analogous to Grunberg and Nissan equation and the hydration numbers are found out at the maxima and minima of the plots of Δe versus x 2.
Abstract: The dielectric constants of some aqueous-organic solvent mixtures have been analysed by an equation analogous to Grunberg and Nissan equation. The hydration numbers are found out at the maxima and minima of the plots of Δe versus x 2. The extent of hydration of organic solvents is discussed in the light of structure of the solvents. It is shown that the equations can be very well applied to aqueous-organic solvent mixtures. An interaction parameter d is defined to fit the dielectric constant data of the mixtures which bears a linear relationship with e2.
15 citations
TL;DR: In this article, the specific resistivity of liquid antimony-tellurium alloys was determined using the DC four probe method, where the cell with the capillary was used to measure potential drops in the temperature range 820 1150 K for pure antimony and six alloy compositions up to X Te = 0.6.
Abstract: The specific resistivity of liquid antimony-tellurium alloys was determined hy the DC four probe method. The cell with the capillary was used to measure potential drops in the temperature range 820 1150 K for pure antimony and six alloy compositions up to X Te = 0.6. Using experimental results obtained in the present study the resistivity change with the alloy composition at constant temperature was derived. It was demonstrated that depending on local ordering in the liquid state there is a interdependence between oxygen activity coefficient, diffusivity, and the alloy conductivity measured in Sb-Te binary system.
13 citations
TL;DR: In this article, the dielectric spectra of the following liquid mixture systems have been measured over the whole absorption region: Glycerol (Gly)/n-butanol, Gly/tbutanol (both at 20°C), and Gly/guaiacol (20,40 and 60°C).
Abstract: The dielectric spectra of the following liquid mixture systems have been measured over the whole absorption region: Glycerol (Gly)/n-butanol, Gly/t-butanol (both at 20°C) and Gly/guaiacol (20,40 and 60°C). The results are comparatively discussed with regard to hetero-interactions, taking into consideration the possibility of internal hydrogen bonding in the case of guaiacol and, generally, of steric constraints.
13 citations
TL;DR: In this article, the density and refractive indices for mixtures of acetonitryle with methanol were measured over the whole composition range at 298.15 K, as well as the relative permittivities at 288.15 and 308.15 k.
Abstract: Density and refractive indices for mixtures of acetonitryle with methanol were measured over the whole composition range at 298.15 K, as well as the relative permittivities at 288.15 K, 298.15 K and 308.15 K. From these data the excess molar volumes, apparent and partial molar volumes of acetonitryle and methanol, the excess relative permittivity, the temperature coefficients of relative permittivity and Kirkwood's correlation factor for investigated mixtures were calculated. The 1H-NMR spectra of these liquid binary mixtures, were recorded at 298 K and the spectral parameters, ΔΔ(ACN-MeOH) were calculated. These structural parameters as functions of concentration suggest the formation of the structures such as clathrate and the most stable complexes of the 2 ACN • MeOH and ACN • 3MeOH types.
TL;DR: In this article, the H-NMR spectra of liquid binary mixtures N-methylformamide (NMF) - N, N-dimethylformamide(DMF) were recorded at 298 K within nearly the whole range of mixed solvent compositions.
Abstract: The 'H-NMR spectra of liquid binary mixtures N-methylformamide (NMF) - N, N-dimethylformamide (DMF), were recorded at 298 K within nearly the whole range of mixed solvent compositions. From these data were found the values of the spectral structural parameter, Δδ(NMF - DMF). The viscosities (η 12 ) of the mixed solvents were measured at 298.15 K, as well as the relative permittivities (e 12 ) and the surface tensions (σ 12 ) at 291.15 K, 298.15 K and 303.15 K. From all these data their deviations from ideality were calculated. Additionally, the temperature coefficients of relative permittivity, α 12 = I/e 12 [de 12 /d(1/T)] and temperature coefficients of surface tensions, γ 12 = -(σ 12 / dT), were found. These quantities, as a function of a mole fraction, deviate very little from their molar values, indicating that the mixtures of NMF DMF can be regarded as almost ideal.
TL;DR: In this paper, the authors measured enthalpies of mixing HM m for binary mixtures of tetrachloroethylene with six alkan-1-ols at 298.15 K using a Parr 1451 solution calorimeter.
Abstract: Enthalpies of mixing HM m have measured for binary mixtures of tetrachloroethylene with six alkan–1–ols (propan–1–ol, butan-1–ol, pentan–1–ol, hexan–1–ol, heptan–l–ol and octan–l–ol) at 298.15 K using a Parr 1451 solution calorimeter. All the studied mixtures present exothermic event and showed minimum negative HM m values in mixtures from propan–1–ol to octan–1–ol in mixtures rich in tetrachloroethylene region around 0.65–0.70 mole fraction. The mixing HM m values increases with the chain length of alkan–1–ols. The experimental data explained in term of dissociation of self–associated alkan–1–mols and tetrachloroethylene.
TL;DR: In this paper, the results of viscosity measurements for mixtures of 1-propanol, 2-pro-panol and 3-amino-1-pro panol with 1,4-dioxane at 20, 30 and 40°C were presented and comparatively discussed.
Abstract: The results of viscosity measurements for mixtures of 1-propanol, 2-propanol, 3-amino-1-propanol and (±)i-amino-2-propanol with 1,4-dioxane at 20, 30 and 40°C are presented and comparatively discussed. From the temperature dependence of viscosity, activation energies are determined.
TL;DR: In this paper, the ternary activity coefficients of the system have been correlated with the composition using the Redlich-Kister, Wilson, NRTL, UNIQUAC, and UNIFAC models.
Abstract: Consistent vapor-liquid equilibrium data at 94kPa have been determined for the ternary system methyl 1,1-dimethylethyl ether (MTBE) + benzene + toluene. The results indicate that the system deviates positively from ideality and that no azeotrope is present. The ternary activity coefficients of the system have been correlated with the composition using the Redlich-Kister, Wilson, NRTL, UNIQUAC, and UNIFAC, models. It is shown that most of the models allow a very good prediction of the phase equilibrium of the ternary system using the pertinent parameters of the binary systems. In addition, the Wisniak-Tamir relations were used for correlating bubble-point temperatures.
TL;DR: In this paper, the liquid-gas phase behavior of a quasi-two-dimensional fluid has been calculated using Zwanzig thermodynamic perturbation theory using hard disks with an inmmersed three-dimensional point dipole.
Abstract: The liquid-gas phase behavior of a quasi two-dimensional fluid has been calculated using Zwanzig thermodynamic perturbation theory. The molecular model is that of hard disks with an inmmersed three dimensional point dipole. Calculations show the fluid phase coexistence for values of temperature lower than the critical temperature.
TL;DR: The gas chromatographic method proposed by as discussed by the authors for simple and accurate measurement of isothermal phase equilibria has been applied to: aliphatic alcohol (n-butanol and n-pentanol)+alkyl benzene (benzene, toluene, o-xylene, p -xylene and ethylbenzinzene) binary mixtures.
Abstract: The gas chromatographic method proposed by us for simple and accurate measurement of isothermal phase equilibria has been applied to: aliphatic alcohol (n-butanol and n-pentanol)+alkylbenzene (benzene, toluene, o-xylene, p-xylene and ethylbenzene) binary mixtures. The present measurements on: benzene with n-butanol, and toluene with n-butanol and n-pentanol are in good agreement with the isothermal phase equilibrium data available in the literature.
TL;DR: In this paper, the total structure factors of liquid Ag-In alloys have been derived by X-ray diffraction measurements, and the partial structure factors are derived from the obtained total structure factor by assuming that they are independent for a concentration range.
Abstract: The total structure factors, S(q), of liquid Ag-In alloys have been derived by X-ray diffraction measurements. The concentration dependence of the first peak position is divided into three groups; on going from Ag to 70 at% Ag, the peak position decreases linearly and it goes to decrease with a more rapid proportion for the concentration range from 70 to 40 at% Ag, and furthermore it becomes nearly constant for the remained concentration range. In order to know the information of a local configuration for this system, the partial structure factors are derived from the obtained total structure factors by assuming that they are independent for a concentration range. And they agree with the results obtained by the reverse Monte Carlo simulation method. From these partial structural information, we propose that the partial structure factors in Ag rich side are different from those in In rich side.
TL;DR: In this article, the anomalous variation of the magnetic susceptibility in liquid alloys of gold with polyvalent metals is discussed in terms of electron concentration and conventional pseudopotential theory.
Abstract: The anomalous variation of the magnetic susceptibility in liquid alloys of gold with polyvalent metals is discussed in terms of electron concentration and conventional pseudopotential theory. The characteristic minima of the susceptibility are shifted systematically towards the Au-rich side if the valency of the alloying element is increased, but considering the average electron concentration they all seem to occur at a critical electron to atom ratio of e/a≍1.6. They are obviously a manifestation of the electronic stabilization which gives rise to the formation of electron compounds in the critical range of composition. Theoretical calculations based on simple model potentials reproduce the typical shape of the observed susceptibility curves and also their systematic variations due to the change in valency. The results indicate that the susceptibility minima are primarily due to interactions between the ionic cores and the electrons which increase the diamagnetic contribution of the conduction e...
TL;DR: In this paper, a scaling approach is developed, based on a well established formula for the viscosity η m of sp liquid metals at their melting points Tm, which leads to an almost universal plot of scaled fluidity δ−1η m against (T/Tm) 1/2 for the liquid alkali metals.
Abstract: Some numerical considerations relating to the potential of mean force at the melting point of Rb metal are first presented, which argue against the existence of a well defined activation energy for the shear viscosity of this liquid. Therefore, a scaling approach is developed, based on a well established formula for the viscosity η m of sp liquid metals at their melting points Tm. This approach is shown to lead to an ‘almost’ universal plot of scaled fluidity η−1η m against (T/Tm) 1/2 for the liquid alkali metals, excluding Li. This metal is anomalous because it is a strong scattering liquid, in marked contrast to the other alkali metals.
TL;DR: In this paper, the effect of Me 4 NI, n-Bu 4 NI and n-Et 3 PhN on the temperature of maximum density of water was determined using a dilatometric technique.
Abstract: The effect of Me 4 NI, n-Bu 4 NI, n-BuEt 3 NI, Et 3 PhNI and Et 4 NBez on the temperature of maximum density of water was determined using a dilatometric technique. The concentration range was from 0.005 m to 0.050 m in all cases. The temperature data was used to calculate Despretz constants using the equations Δθ = θ sol - θ w and Δθ = K m m, where θ sol - θ w is is the difference between temperature of maximum density of the solution and of water, K m is the Despretz constant. The equation of Kaulgud and Pokale Δθ + 1,074 m 3/2 =K m m was also used. All the calculated K m 's are negative, that is to say, the effect of the salts is to lower the temperature of maximum density. The individual ion constants were calculated using literature values for the iodide and the tetraethyl ammonium ions. The order followed by the absolute values of the constants is Me4N + < n-BuEt 3 N + < Et 3 PhN + < Bu 4 N + . The results confirm the proposal of Kaulgud and Pokale in the sense of having the quaternary ammonium ions conserving their influence on the structure of water for temperatures in the neighborhood of that of maximum density of water.
TL;DR: In this article, experimental results for anthracene dissolved in seven binary alkane+3-methoxy-1-butanol solvent mixtures at 25°C were used to test two mathematical representations based upon the combined Nearly Ideal Binary Solvent (NIBS)/Redlich-Kister and Modified Wilson equations.
Abstract: Experimental solubilities are reported for anthracene dissolved in seven binary alkane+3-methoxy-1-butanol solvent mixtures at 25°C. The alkane cosolvents studied were hexane, heptane, octane, cyclohexane, methylcyclohexane, 2,2,4-trimethylpentane and tert-butylcyclohexane (also called (1,1-dimethylcyclohexane). Results of these measurements are used to test two mathematical representations based upon the combined Nearly Ideal Binary Solvent (NIBS)/Redlich-Kister and Modified Wilson equations. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being 0.6% and 0.9% for the Combined NIBS/Redlich-Kister and Modified Wilson equations, respectively.
TL;DR: In this article, the results of these measurements were used to test two mathematical representations based upon the combined Nearly Ideal Binary Solvent (NIBS)/Redlich-Kister and Modified Wilson equations.
Abstract: Experimental solubilities are reported for anthracene dissolved in seven binary alkane+2-isopropoxyethanol solvent mixtures at 25°C. The alkane ccsolvents studied were hexane, heptane, octane, cyclohexarie, methylcyclohexane, 2,2,4-trimethylpentane and tert-butylcyclohexane (also called (1,1-dimethylethyl)cyclohexane). Results of these measurements are used to test two mathematical representations based upon the combined Nearly Ideal Binary Solvent (NIBS)/Redlich-Kister and Modified Wilson equations. For the seven systems studied, both equations were found to provide an accurate mathematical representation of the experimental data, with an overall average absolute deviation between measured and calculated values being 0.5% and 0.7% for the Combined NIBS/Redlich-Kister and Modified Wilson equations, respectively.
TL;DR: In this article, the authors measured the density ρ and the dynamic viscosity η of the ternary mixture heptane+methylcyclohexane+1-methylnaphtaiene at 303.15, 323.15 and 343.15K at atmospheric pressure for molar fractions xi = 0, 0.125, 0., 0.375, 0, 5, 0.625, 0, 0.75, 0
Abstract: The density ρ and the dynamic viscosity η of the ternary mixture heptane+methylcyclohexane+1-methylnaphtaiene were measured at 303.15, 323.15 and 343.15K at atmospheric pressure for molar fractions xi =0, 0.125, 0.25, 0.375, 0.5, 0.625, 0.75, 0.875 and 1 (with Σi=1 3 xi = 1). The experimental data for η and ρ (135 values) can be used to evaluate the excess volume VE and the excess energy of activation for viscous flow ΔGE . The density is modelled over the entire experimental domain of composition and temperature with an absolute average deviation of 0.03% and the dynamic viscosity with an absolute average deviation of 0.7%.
TL;DR: In this article, the partial structure factors of molten copper haildes (CuCl, CuBr and CuI) have been derived from the observed total structure factors by means of the Reverse Monte Carlo simulation technique.
Abstract: The partial structure factors of molten copper haildes (CuCl, CuBr and CuI) have been derived from the observed total structure factors by means of the Reverse Monte Carlo simulation technique. The static dielectric functions are also obtained using these partial structure factors and it is found that these experimental dielectric functions satisfy either the inequality form e(q)e1 or e(q) < 0.
TL;DR: In this article, the Redlich-Kister relation was used to estimate the binary interaction parameters and standard errors for the binary mixtures of DMSO with methyl amine and trimethyl amine.
Abstract: Experimental values of density, viscosity and ultrasonic velocity are presented for the binary mixtures of dimethyl sulphoxide (DMSO) with methyl amine (CH 3 NH 2 ), dimethyl amine ((CH 3 ) 2 NH) and trimethyl amine ((CH 3 ) 3 N) at 303.15 K over the entire mole fraction of the mixture components. From these data, excess isentropic compressibility (β s E ), excess intermolecular free-length (L f E )), excess acoustic impedance (Z E ), excess viscosity (η E ) and excess volume (V E ) have been calculated. These quantities are further fitted to the Redlich-Kister relation to estimate the binary interaction parameters and standard errors. The results are analysed in terms of nature and degree of interaction between the component molecules. The nature of variation of these excess parameters provides information about the type of interaction taking place in these binary systems.
TL;DR: In this paper, sound velocities for Binary mixtures of 1,1,1-Trichloroethane (TCE) with methyl ethyl ketone, methyl isobutyl ketones, acetophenone, cyclohexanones, methyl acetate, ethylacetate, n-propyl acetates and n-butyl acetate were determined at 303.15 K.
Abstract: Sound velocities for Binary mixtures of 1,1,1-Trichloroethane (TCE) with methyl ethyl ketone, methyl isobutyl ketone, acetophenone, cyclohexanone, methyl acetate, ethyl acetate, n-propyl acetate and n-butyl acetate were determined at 303.15 K. Isentropic compressibility (Ks ) were computed from sound velocity and density data, derived from excess volume. The deviation in isentropic compressibility (Ks ) exhibits negative values for mixtures of TCE with methyl ethyl ketone, methyl isobutyl ketone, acetophenone, cyclohexanone ethyl acetate, n-propyl acetate and n-butyl acetate. On the other hand, the quantity is positive over the entire range of composition for the mixtures of TCE with methyl acetate. The results are explained in terms of interactions between unlike molecules. Further, the experimental sound velocity data have been analysed in terms of free length theory (FLT) and collision factor theory (CFT).
TL;DR: In this paper, the parital volumes of oxalic, malonic, succinic, glutaric and adipic acids have been determined in water+methanol (5, 10, 20, 30 and 40 wt%) mixtures from density measurements in varying ranges of concentration at four different temperatures ranging from 288.15 to 318.15 K.
Abstract: The parital molar volumes of oxalic, malonic, succinic, glutaric and adipic acids have been determined in water+methanol (5, 10, 20, 30 and 40 wt%) mixtures from density measurements in varying ranges of concentration at four different temperatures ranging from 288.15 to 318.15 K. The density data have been analysed by means of Masson equation. The apparent molar isentropic compressibilities of these acids have been determined in these water+methanol mixtures from sound velocity measurements in varying ranges of concentration at 298.15 K. The solvation numbers of the acids have been determined in these solvents. The results are discussed in terms of solute-solvent interactions.
TL;DR: In this paper, the principal refractive indices (n 0 and ne ) of three nematic liquid crystals were measured using an Abbe refractometer with a large refractive index prism.
Abstract: Temperature dependence of the principal refractive indices (n 0 and ne ) of three nematic liquid crystals were measured using an Abbe refractometer with a large refractive index prism. The variatio...
TL;DR: In this paper, the excess free energy of mixing ΔFtotal ΔFAB in the binary mixtures of long chain alchols and amines in nonpolor solvent carbon tetrachloride have been calculated with the help of a proposed equation.
Abstract: Excess free energy of mixing ΔFtotal ΔFAB in the binary mixtures of long chain alchols and amines in nonpolor solvent carbon tetrachloride have been calculated with the help of our proposed equation. The novelty of our equation is that it involves separate estimation of excess free energy of mixing due to interaction between polar-polar molecules, polar-induced nonpolar molecules and induced nonpolar molecules and a picture of molecular interaction in these mixtures has been elicited with the help of these parameters.