Showing papers in "Physics and Chemistry of Liquids in 2000"
TL;DR: In this article, a Redlich-Kister function was fitted to the refractive indices for the binary liquid mixtures: {hexane or heptane + ethanol, {o-xylene + benzene} and {cyclohexane+ benzene, toluene or hexane} were measured at 298.15 K.
Abstract: Refractive indices for the binary liquid mixtures: {hexane or heptane + ethanol}, {o-xylene + benzene} and {cyclohexane + benzene, toluene or hexane} were measured at 298.15 K. Excess refractive indices were calculated and fitted to a Redlich-Kister function. Using some mixture rules (Lorentz-Lorenz, Dale -Gladstone, Eykman, Oster, Arago-Biot and Newton), predictions for vE have been made and compared with experimental data taken from the literature. Furthermore the Sugden equation has been used in two different ways for predicting excess surface tensions: the first one starting from densities and the other one from refractive indices. Results are plotted together with the literature data.
68 citations
TL;DR: In this paper, experimental data on densities and excess volumes (VE) for methyl acrylate (MA)+, ECA+ or butyl acrylated (BA)+ 1-heptanol, +1-octanol,+1-decanol and +1dodecanol are reported at (298.15 and 308.15) K. The variations in excess volumes with the alkyl chain length of both the components are explained in terms of molecular interactions.
Abstract: New experimental data on densities and excess volumes (VE) for methyl acrylate (MA)+, ethyl acrylate (EA)+, or butyl acrylate (BA)+1-heptanol, +1-octanol, +1-decanol and +1-dodecanol are reported at (298.15 and 308.15) K. The excess volumes were fitted to Redlisch-Kister type equation. The variations in excess volumes with the alkyl chain length of both the components are explained in terms of molecular interactions.
53 citations
TL;DR: Different methods, based on application of physicochemical properties of liquid binary mixtures and 1H-NMR spectral measurements, used in the analysis of intermolecular interactions and estimation of the internal structure of these mixtures are reviewed in this paper.
Abstract: Different methods, based on application of studies of intensive physicochemical properties of liquid binary mixtures and 1H-NMR spectral measurements, used in the analysis of intermolecular interactions and estimation of the internal structure of these mixtures and here reviewed.
51 citations
TL;DR: In this article, the ultrasonic velocity, u, viscosity, η, and density, ρ of dimethylsulphoxide (DMSO), 1-butanol, 1-hexanol, and their binary mixtures, where DMSO is common component, have been measured at 303.15 K. The experimental values of u have been compared with those calculated by using Nomoto and Van Dael relations.
Abstract: The ultrasonic velocity, u, viscosity, η, and density, ρ of dimethylsulphoxide (DMSO), 1-butanol, 1-hexanol, 1-octanol, and of their binary mixtures, where DMSO is common component, have been measured at 303.15 K. From the experimental data, excess isentropic compressibility, K E s, excess intermolecular free length, LE f, excess velocity, u E, excess acoustic impedance, Z E, excess viscosity, ηE, excess free energy of activation of viscous flow, G∗E, and excess rheochore, [R E] have been calculated. The behaviours of excess functions with composition of the mixtures suggest that the structure-breaking effect dominates over the interaction effect between the component molecules. Furthermore, the experimental values of u and η were fitted by empirical equations stating their dependence on composition of the mixtures. The experimental values of u have been compared with those calculated by using Nomoto and Van Dael relations.
40 citations
TL;DR: In this article, the authors calculated the excess molar volumes (VE) and average thermal expansivities (α) of water, n-butylamine (NBA), SBA, and TBA from the density data at temperatures ranging from 298.15 to323.15 K. The negative excess volumes have been interpreted primarily by strong chemical interaction leading to the formation of 1:1 complexes through H-bonding and hydrophobic hydration causing significant contraction of volume.
Abstract: Excess molar volumes (VE ) and average thermal expansivities (α) of the systems, water (W) + n-butylamine (NBA), W + sec-butylamine (SBA), and W + tert-butylamine (TBA), have been calculated from the density data at temperatures ranging from 298.15–323.15 K. The VE and α values have been plotted as functions of mole fraction of amines. The systems show large negative excess volumes, magnitude of which varies in the order, W + TBA > W + SBA > W + NBA. The curves are found to be symmetrical along the composition axis, with minima occurring at 0.5 mole fraction of butylamines. The negative excess volumes have been interpreted primarily by two effects: (i) strong chemical interaction leading to the formation of 1:1 complexes through H-bonding and (ii) hydrophobic hydration causing significant contraction of volume.
18 citations
TL;DR: In this article, an extensive experimental study of two different ternary mixtures has been undertaken which aimed at showing the effect of composition, temperature and pressure on viscosity and density.
Abstract: Recently, an extensive experimental study of two different ternary mixtures has been undertaken which aimed at showing the effect of composition, temperature and pressure on viscosity and density. The ternary mixture heptane + methylcyclohexane + 1-methylnaphtalene has been chosen as it can be, in some ways, a synthetic representation of a C5+ distillation fraction of a petroleum crude oil. The ternary mixture water + diacetone-alcohol + 2-propanol has the distinctive feature of involving components which have important interactions. The key issue of this study is the fairly high number of samples within the ternary diagram, as the first mixture is described by 45 compositions and the second one by 66 compositions. The viscosity of both mixtures have then been measured at three temperatures (303.15, 323.15, and 343.15K) and 6 pressures (0.1, 20,40,60,80 and 100 MPa) using a high pressure falling body viscometer which allowed to collect 1998 experimental data. Our entire set of data have then been...
17 citations
TL;DR: In this article, the interfacial tension of polyethylene glycol (PEG)/potassium phosphate two-phase systems was measured by the rotating drop method and it was shown that the interface tension was as low as 0.001 dyne/cm and increased with increases in the total concentrations of both PEG and potassium phosphate.
Abstract: The interfacial tension of Polyethylene glycol (PEG)/potassium phosphate two-phase systems was measured by the rotating drop method. The interfacial tension was as low as 0.001 dyne/cm and increased with increases in the total concentrations of both PEG and potassium phosphate in two-phase systems. The increase in the interfacial tension was a function of the concentration differences of PEG and potassium phosphate between the top and the bottom phases which was confirmed by the tie line analysis. The interfacial tension was affected also by the molecular weigth of PEG. At low PEG molecular weights, the increase in the molecular weight greatly increased the interfacial tension, but at high molecular weights, the interfacial tension varied less with the molecular weight.
17 citations
TL;DR: In this paper, the Kirkwood's correlation factors (g K ) were calculated in terms of interactions of acetonitrile with butan-1-ol and butan2-ol.
Abstract: The densities (d12 ) and relative permittivities (e12) of liquid binary mixtures of acetonitrile-butan-l-ol and acetonitrile-butan-2-ol were measured at 288.15 K, 293.15 K, 298.15 K, 303.15 K and 308.15 K, as well as refractive indices (n D 12) at 298.15 K and surface tensions (σ12) at 293.15 K, 298.15 K and 303.15 K. From all these data, the molar volumes (V m ), apparent molar volumes (V i, φ), temperature coefficients of relative permittivities (α12) and surface tensions (k) and their deviations from ideality were calculated. Additionally, the Kirkwood's correlation factors (g K ) were found. The values of these properties are discussed in terms of interactions of acetonitrile with butan-1-ol and butan-2-ol.
14 citations
TL;DR: In this paper, a Redlich-Kister type function in terms of mole fraction was used to measure the excess molar volumes of binary mixtures of water and 1,2-alkane diols.
Abstract: From dilatometric method at 293.15,303,15, and 313.15K for binary mixtures of water and 1,2-alkane diols, the excess molar volumes, VE and the partial molar volumes, V i of both components at 293.15 K have been obtained as a function of mixtures composition. Excess molar volumes were calculated and correlated by a Redlich-Kister type function in terms of mole fraction. The partial molar volumes have been extrapolated to zero concentration to obtain the limiting values at infinite dilution, V 0 i . All mixtures showed negative values and decreases with the chain length of diols. The values become less negative with increasing temperature. The results are explained in terms of dissociation of the self-associated diol molecules and the formation of aggregates between unlike molecules.
14 citations
TL;DR: In this article, sound velocity and density data for binary mixtures of N-methyl-cyclohexylamine with benzene, toluene, o-xylene, m xylene, p xylene and nitrobenzene at 303.15k have been reported.
Abstract: New experimental sound velocity and density data for binary mixtures of N-methyl-cyclohexylamine with benzene, toluene, o-xylene, m-xylene, p-xylene, chlorobenzene, bromobenzene and nitrobenzene at 303.15K have been reported. The sound velocity data were also used to compute the isentropic compressibilities (Ks ). The deviation in isentropic compressibilities (ΔKs ) from ideal behaviour suggests that the existence of weak dipole-induced dipole and dipole-dipole interactions between unlike molecules.
13 citations
TL;DR: In this paper, the refractive indices of the mixtures methyl acetate+ethanol+2-propanol, methyl acacetate+propanol, methyl alkyl-propanol and methyl acyclic acid+2 -propanoline have been determined experimentally as a function of composition at the temperature range 28815-30815K and atmosphere parameters of polynomial equations which represent the composition and temperature dependence of the corresponding derived magnitude are gathered.
Abstract: The refractive indices of the mixtures methyl acetate+ethanol+2-propanol, methyl acetate+ethanol and methyl acetate+2-propanol have been determined experimentally as a function of composition at the temperature range 28815–30815K and atmosphere Parameters of polynomial equations which represent the composition and temperature dependence of the corresponding derived magnitude are gathered The applicability of semiempirical equations is analyzed in order to estimate the ternary changes of refractive indices on mixing at these temperatures by means of only binary derived values
TL;DR: In this paper, the concept of stability is reviewed from a general viewpoint, showing how it applies to completely general cases of binary phase equilibrium, from low to high pressure ranges, using excess Gibbs energy models and equations of state.
Abstract: Stability analysis should be a standard practice for testing the physical validity of phase equilibrium states predicted by thermodynamic models however, it is seldom used in routine work of experimental data modeling. Lack of stability analysis may result in potential modeling pitfalls or in an inadequate prediction of data. In this contribution the concept of stability is reviewed from a general viewpoint, showing how it applies to completely general cases of binary phase equilibrium, from low to high-pressure ranges. Graphical examples are given using excess Gibbs energy models and equations of state.
TL;DR: In this paper, density measurements have been made on aqueous solutions of t-BuEt3NI, s-Bu Et3N+, s-Et 3N+ and Et 4N+ at 298,15 K from 0,01 to 0,05 m. The apparent molal volumes calculated from the V 2,ϕ (m) plots for the salts show a decrease value.
Abstract: Density measurements have been made on aqueous solutions of t-BuEt3NI, s-BuEt3NI, i-BuEt3NI, Bu4NI and Et4NI at 298,15 K from 0,01 to 0,05 m. The apparent molal volumes V02 calculated from the V 2,ϕ (m) plots for the salts show a decrease value: n-BuEt3NI > i-BuEt3NI > s-BuEt3NI > t-BuEt3NI. The data analysis may suggest that the cations with the butyl isomers perform two groups: n-BuEt3N+ and i-BuEt3N+ with the highest V 2 0, and t-BuEt3N+ and s-BuEt3N+ similar to Et4N+ one. The peculiarities of the experimental observation may be interpreted as a consequence of the structural effect over the intermolecular forces that affect the solute-water interactions deeply.
TL;DR: In this article, the pure component vapor pressure of ETBE with hexane and with heptane was measured at 94kPa and the activity coefficients and boiling points of the solutions were correlated with its composition by the Redlich-Kister, Wohl, Wilson, UNIQUAC, NRTL, and Wisniak-Tamir equations.
Abstract: Pure-component vapor pressure of ethyl 1,1-dimethylethyl ether and vapor-liquid equilibrium for the binary systems of ETBE with hexane and with heptane have been measured at 94kPa. Both systems deviate slightly from ideal behavior, can be described as regular solutions and do no present an azeotrope. The activity coefficients and boiling points of the solutions were correlated with its composition by the Redlich-Kister, Wohl, Wilson, UNIQUAC, NRTL, and Wisniak-Tamir equations.
TL;DR: In this article, the excess volume VE of the ternary water + diacetone alcohol (or DAA) + 2-propanol and of the three binaries water + DAA, water+ 2-Propanol, and DAA + 2 -propanoline was evaluated from experimental density data (2772 values) as a function of the pressure P (between 0.1 MPa and 65 MPa), the temperature T (303.15K, 323.15k, and 343.15 K) and the composition.
Abstract: The excess volume VE of the ternary water + diacetone alcohol (or DAA) + 2-propanol and of the three binaries water + DAA, water + 2-propanol and DAA + 2-propanol was evaluated from experimental density data (2772 values) as a function of the pressure P (between 0.1 MPa and 65 MPa), the temperature T (303.15K, 323.15K and 343.15K) and the composition. Various representative models are discussed. It is possible to account for the values of the density with an average absolute deviation of about 0.06% in the experimental P-T domain.
TL;DR: In this article, the phase separation of polyethylene glycol (PEG)/salt aqueous two-phase systems was investigated and it was shown that phase separation occurs when the concentration of salt in the PEG-free solvent reaches its solubility limit.
Abstract: Salt in polyethylene glycol (PEG)/salt aqueous two-phase systems was excluded by PEG and concentrated in the solvent volume available for dissolution of salt (PEG-free solvent). The concentration of salt in the PEG-free solvent of the PEG-rich phase was the same as that at the critical point regardless of the compositions of the PEG/salt two-phase systems. This explained that the phase separation of PEG/salt two-phase systems occurs when the concentration of salt in the PEG-free solvent reaches its solubility limit. The concentration of salt required in the PEG-free solvent for the phase separation was lower with higher molecular weight of PEG. The solubility of salt in the PEG-free solvent decreased with increases in the molal surface tension increment of salt. The solubility limit of salt in the PEG-free solvent was 0.93 M for ammonium sulfate, 0.77 M for potassium phosphate, 0.75 M for sodium tartrate, 0.67 M for sodium phosphate, and 0.53 M for potassium citrate.
TL;DR: In this article, the catalytic effect of lithium perchlorate on ene reaction of cis-cyclooctene with diethyl azodicarboxylate, 4-phenyl-1,2,4-triazoline-3,5-dione and the metallo-ene reaction of diallyldibutyltin with diethodibutyllin was studied in different solvents.
Abstract: The catalytic effect of lithium perchlorate on ene reaction of cis-cyclooctene with diethyl azodicarboxylate, 4-phenyl-1,2,4-triazoline-3,5-dione and the metallo-ene reaction of diallyldibutyltin with diethyl azodicarboxylate has been studied in different solvents like acetonitrile, acetone, diethyl ether, dimethylformamide and ethyl acetate.
TL;DR: In this paper, the authors measured consistent vapor-liquid equilibria for the binary systems of ETBE with benzene and cyclohexane at 94.00 kPa.
Abstract: Consistent vapor-liquid equilibria for the binary systems of ETBE with benzene and cyclohexane at 94.00 kPa have been measured. Both systems show slightly positive deviation from ideal behavior and do no present azeotropic behavior. The activity coefficients and boiling points of the solutions were correlated with its mole fractions by the Redlich-Kister, Wohl, Wilson, UNIQUAC, NRTL, and Wisniak -Tamir equations. The data were also compared with UNIFAC predictions.
TL;DR: In this paper, the authors present a systematic study of the apparent molar volumes and the viscosities of DL-α-alanine in aqueous ethanol solutions at 25,00°C.
Abstract: In this work we present a systematic study of the apparent molar volumes and the viscosities of DL-α-alanine in aqueous ethanol solutions at 25,00°C. The molar fractions of ethanol for the solvent mixtures were selected taking into account that thermodynamic properties such as partial molar volumes and heat capacities of these mixtures show a transition concentration around X et = 0,1 at which its behavior suffers a deep change. Besides, this ethanol concentration is near to that required to produce 50% of protein denaturation. The results were used to evaluate the limiting partial molar volume V0 of the solute the volume changes associated with its transfer from water to aqueous ethanol solutions and the viscosity B coefficients of DL-α-alanine. The values obtained for the transference molar volumes and the viscosity B coefficients of alanine in the aqueous mixtures show a minimum at X et = 0,1000. The results are discussed in terms of changes in the solvent structure (Ref. [1])
TL;DR: In this paper, a simple form of the N-body potential and the thermodynamically self-consistent variational modified hypernetted chain (VMHNC) theory of liquid noble and transition metals were combined to calculate structural, thermodynamic and atomic transport properties of various liquid noble metal and transition metal.
Abstract: We have investigated a number of structural, thermodynamic and atomic transport properties of various liquid noble and transition metals. The underlying theory combines a simple form of the N-body potential and the thermodynamically self-consistent variational modified hypernetted chain (VMHNC) theory of liquid. The static structure factors calculated by using the VMHNC resemble, as expected, the hard sphere (HS) values. Consequently the HS model is used to calculate thermodynamic properties, viz. the specific heat, entropy, isothermal compressibility and the shear viscosity of liquid Ni, Cu, Ag, and Au. The results are in reasonable accord with the experimental values.
TL;DR: In this article, the partial enthalpies of silicon, vanadium, zirconium, niobium and molybdenum in liquid tin at 1173 K were measured at high dilution by direct reaction calorimetry (drop method) with the help of a Tian-Calvet high-temperature calorimeter.
Abstract: The partial enthalpies of silicon, vanadium, zirconium, niobium and molybdenum in liquid tin at 1173 K were measured at high dilution by direct reaction calorimetry (drop method) with the help of a Tian-Calvet high-temperature calorimeter. When referred to liquid metals we found h Si /kJ.mol -1 = 99.4-263.0 x Si , h v /kJ.mol -1 = 102.8 - 14.8 x v , h Zr /kJ.mol -1 = 124.2 - 18.1 x Zr , h Nb /kJ.mol -1 = 81.7 + 72.5 x Nb and h Mo /kJ.mol -1 = 115.4- 159.9 x Mo . The limiting partial enthalpies were deduced by extrapolation at infinite dilution.
TL;DR: The two-dimensional boundary layer equations for a class of non-Newtonian fluids, for which the apparent viscosity can be expressed as a polynomial in the second scalar invariant of the rate of strain tensor, have been derived in this article.
Abstract: The two-dimensional boundary layer equations for a class of non-Newtonian fluids, for which the apparent viscosity can be expressed as a polynomial in the second scalar invariant of the rate of strain tensor, have been derived. These equations have been employed to analyse the flow near a stagnation point over a stationary impermeable wall. The non-Newtonian effects on the boundary layer velocity profile and the wall skin friction have been studied, and compared with the corresponding Newtonian fluid. The fluid velocity in the boundary layer has been shown to be retarded by the non-Newtonian effect while the skin friction increases proportionate to it.
TL;DR: In this article, density and viscosity measurements on binary mixtures of methanol+p-xylene, n-propanol +p-exylene and n-butanol+pxylene at 303.15, 313.15 and 323.15K are reported.
Abstract: Density and viscosity measurements on the binary mixtures of methanol+p-xylene, n-propanol+p-xylene and n-butanol+p-xylene at 303.15, 313.15 and 323.15K are reported The representation of the data by common mixing rules is also studied.
TL;DR: In this paper, the ternary mixture and the corresponding binary mixtures (benzene + 1-propanol, benzene + ethyl acetate, and 1-polypanol + polyacetate) have been measured at the temperature 298.15 K. The equation of Redlich-Kister has been used for fitting the excess properties of binary mixture.
Abstract: Densities and viscosities of the ternary mixture (benzene + 1-propanol + ethyl acetate) and the corresponding binary mixtures (benzene + 1-propanol, benzene + ethyl acetate and 1-propanol + ethyl acetate) have been measured at the temperature 298.15 K. From these measurements excess volumes, VE , excess viscosities, ηE, and excess Gibbs energies of activation for viscous flow, G∗E , have been determined. The equation of Redlich-Kister has been used for fitting the excess properties of binary mixtures. The excess properties of the ternary system were fitted to Cibulka's equation.
TL;DR: In this article, the de Haas-van Alphen effect is considered theoretically in a fractional quantum Hall (FQH) liquid and it is pointed out that laboratory experiments on GaAs/AlGaAs heterojunctions, plus the analogue of the Clausius-Clapeyron equation in an applied magnetic field, allow schematic analysis of the orbital magnetism of the FQH liquid.
Abstract: A recent paper of Wu et al., discusses thermodynamic observables in a fractional quantum Hall (FQH) liquid. In particular the de Haas-van Alphen effect is considered theoretically. Here, it is pointed out that laboratory experiments on GaAs/AlGaAs heterojunctions, plus the analogue of the Clausius-Clapeyron equation in an applied magnetic field, allow schematic analysis of the orbital magnetism of the FQH liquid. There is general agreement with the theoretical results of Wu et al.
TL;DR: In this paper, experimental results of trans-stilbene dissolved in sixteen organic solvents at 25.0°C were used to test the applications and limitations of expressions derived from Mobile Order theory.
Abstract: Experimental solubilities are reported for trans-stilbene dissolved in sixteen organic solvents at 25.0°C. Solvents studied contained chloro-, cyano-, hydroxy-, fluoro-, and ether-functional groups. Results of these measurements, combined with previously published solubility data, are used to test the applications and limitations of expressions derived from Mobile Order theory. For the 34 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. The average absolute deviation between predicted and observed values is circa 20%. The deviation increases significantly to 1,210% when ideal solution behavior is assumed.
TL;DR: In this paper, the entire composition range was measured for three binary systems - butan-1-ol(1) + chlorobenzene(2), 2-methylpropan-2-ol (1)+ chlorobenensene (2), using a Swietoslawski type ebulliometer, and the composition (x 1) vs. temperature (T) data were found to be well represented by Wilson model.
Abstract: Vapor-liquid equilibria at 94.6 kPa, over the entire composition range were measured for three binary systems - butan-1-ol(1) + chlorobenzene(2), 2-methylpropan-1-ol(1) + chlorobenzene(2), 2-methylpropan-2-ol(1) + chlorobenzene(2)- using a Swietoslawski type ebulliometer. The composition (x 1) vs. temperature (T) data were found to be well represented by Wilson model.
TL;DR: In this paper, the 1 H-NMR spectra of liquid binary mixtures of acetonitrile and propan-2-ol, were recorded at 298 K over almost the whole range of the mixed solvent compositions.
Abstract: The 1 H-NMR spectra of liquid binary mixtures of acetonitrile and propan-2-ol, were recorded at 298 K over almost the whole range of the mixed solvent compositions. From these data were found the values of the spectral parameter, Δδ(ACN-PrOH-2). The densities (d 12 ) and relative permittivities (e 12 ) of the mixed solvent were measured at 288.15 K, 293.15 K, 298.15K, 303.15 K and 308.15K, as well as refractive indices at 298.15 K. From all these data, the molar volumes (V m ), temperature coefficients of relative permittivities (α 12 ) and their deviations from ideality were calculated. Additionally, the Kirkwood's correlation factors (g K ) were found. The values of these properties are discussed in terms of interactions of acetonitrile with propan-2-ol.
TL;DR: In this article, the experimental results along with the data available in the literature on molar excess Gibbs energies, G E m, activity coefficients at infinite dilution, In γ∞ i, and molar enthalpies, HE m, for α,ω-dihaloalkanes + benzene or + tetrachloromethane mixtures are examined on the basis of the DISQUAC group contribution model.
Abstract: Molar excess enthalpies, H E m, at 298.15K and atmospheric pressure have been determined for three binary liquid mixtures [x{1,3-dichloropropane or 1,4-dichlorobutane and 1,6-dichlorohexane} + (1 - x) tetrachloromethane]. These experimental results along with the data available in the literature on molar excess Gibbs energies, G E m, activity coefficients at infinite dilution, In γ∞ i , and molar excess enthalpies, H E m, for α,ω-dihaloalkanes + benzene or + tetrachloromethane mixtures are examined on the basis of the DISQUAC group contribution model.
TL;DR: In this article, density and viscosity measurements on the binary mixtures of methanol + trichloro-ethylene, n-propanol + triacetylene, and n-butanol + tricloroethylene are reported at 303.15, 313.15 and 323.15K.
Abstract: Density and Viscosity measurements on the binary mixtures of methanol + trichloro-ethylene, n-propanol + trichloroethylene, and n-butanol + trichloroethylene binary mixtures at 303.15, 313.15 and 323.15K are reported. The representation of the data by simple mixing rules is also studied.