(p,ρ,T,x) and viscosity measurements of {x1n-heptane+(1−x1)n-octane} mixtures at high temperatures and high pressures (original) (raw)
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Journal of the Serbian Chemical Society, 2017
Densities (ρ) and viscosities (η) of the binary systems n-heptane with alcohols (ethanol, propan-1-ol and propan-2-ol) were measured at temperatures between 288.15 and 308.15 K and at atmospheric pressure, over the whole composition range. The excess values of molar volume (V E) and viscosity (η E) were calculated from experimental measurements. The excess functions of the binary systems were fitted to Redlich-Kister Equation. Comparison between experimental excess molar volume and the one calculated from Flory and Prigogine-Flory-Patterson theories, has also been done. The viscosity results were fitted to the equations of Grunberg-Nissan, Heric-Brewer, Jouyban-Acree and McAllister. Also, the activation energies of viscous flow have been obtained and their variations with compositions have been discussed.
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International Journal of Thermophysics, 1991
New absolute measurements of the viscosity of binary mixtures of n-heptane and n-undecane are presented. The measurements, performed in a vibrating-wire instrument, cover the temperature range 295-335 K and pressures up to 75 MPa. The concentrations studied were 40 and 70 %, by weight, of n-heptane. The overall uncertainty in the reported viscosity data is estimated to be _+0.5 %. A recently extended semiempirical scheme for the prediction of the thermal conductivity of mixtures from the pure components is used to predict successfully both the thermal conductivity and the viscosity of these mixtures, as a function of composition, temperature, and pressure.
Viscosity and density of the ternary mixture heptane+methylcyclohexane+1-methylnaphthalene
International Journal of Thermophysics, 1997
The dynamic viscosity q and the density p of the ternary mixture heptane (mole fraction .x~) + methylcyclohexane (mole fraction .v2) + I-methylnaphthalene (mole fraction .v3) were measured as a function of temperature T (303.15. 323.15, and 343.15 K) and pressure P (~< 100 MPa). The experimental results correspond to 378 values of q and p. With reference to the 54 values previously published on pure substances and 378 values for the three associated binaries, the system is globally described by 810 experimental values for various values of P, T, and composition.
Density and Viscosity of Mixtures of n-Hexane and 1-Hexanol from 303 to 423 K up to 50 MPa
International Journal of Thermophysics, 2002
ABSTRACT Experimental results for the density and viscosity of n-hexane+1-hexanol mixtures are reported at temperatures from 303 to 423 K and pressures up to 50 MPa. The binary mixture was studied at three compositions, and measurements on pure 1-hexanol are also reported. The two properties were measured simultaneously using a single vibrating-wire sensor. The present results for density have a precision of ±0.07% and an estimated uncertainty of ±0.3%. The viscosity measurements have a precision of ±1% and an estimated uncertainty of ±4%. Representations of the density and viscosity of the mixture as a function of temperature and pressure are proposed using correlation schemes.
Fluid Phase Equilibria, 1998
Ä Ž . 4 Viscosities and densities of x di-n-butyl ether q x 1-propanolq 1 y x y x n-octane and their corre-1 2 1 2 sponding binary mixtures were measured at the temperatures of 293.15, 298.15, 303.15 and 308.15 K under atmospheric pressure. Kinematic viscosities were determined using a capillary viscosimeter, and densities were measured by a vibrating tube densimeter. The viscosity deviations and Gibbs free energies of activation for flow were evaluated. All the experimental values were compared with the results obtained with different predictive methods. q
Empirical and Semi-theoretical Methods for Predicting the Viscosity of Binary n Alkane Mixtures
International Journal of Thermophysics, 2005
In this study, empirical and semi-theoretical methods for predicting the viscosity of binary mixtures of n-alkanes are presented at atmospheric pressure and in the temperature range from 288 to 333 K. In the empirical viscosity calculation method, a modified version of the Andrade equation and a simple mixture rule are used. The proposed semi-theoretical method employs both the Enskog's hard-sphere theory for dense fluids and the principle of corresponding states. The viscosities of binary mixtures of n-heptane with n-hexane and n-nonane covering different compositions were calculated using these methods which require only critical properties and the normal boiling point as input data. The predictions were compared with accurate experimental data in the literature. Highly satisfactory results were obtained. The percent average absolute deviations amount to 1.2 and 0.9% utilizing the empirical and semi-theoretical viscosity methods, respectively, for 27 data points.
The Journal of Chemical Thermodynamics, 2013
Mixture of {poly(ethylene glycol) dimethyl ether 2000 (PEGDME2000) + poly(propylene glycol) 400 (PPG400) + water} forms an aqueous two phase system. For this system the binodal curves were measured at two temperatures from which the single phase region was obtained. The density, speed of sound and viscosity measurements were performed in the single phase region for {poly(ethylene glycol) dimethyl ether 2000 (PEGDME2000) + poly(propylene glycol) 400 (PPG400) + water} system and the corresponding binary ((PPG400) + water) solutions at T = (293.15, 298.15, 303.15, 308.15, and 313.15) K. From these measurements, values of the excess molar volume (V m E) and isentropic compressibility deviation (ΔK S) were calculated and correlated to the modified Wilson and polymer NRTL models. The viscosity values of binary and ternary solutions were correlated by the Eyring-modified Wilson and Eyring-NRTL models. From the density data for the binary and ternary solutions at dilute range, the apparent specific volumes at infinite dilution values were also determined. Some information regarding the segment-solvent and segment-segment interactions is obtained from these values.
Russian Journal of Physical Chemistry A, 2012
An Anton Paar 4500 densimeter was used to measure the density of methanol-heptane and meth anol-octane solutions in the region of low alkane concentrations over the temperature range 288.15-328.15 K. The experimental data were used to calculate the apparent, partial, and excess molar volumes of alkanes. Vis cosity was measured with an Ubbelohde viscometer at 298.15 K. The NMR spectra were recorded on a Bruker Avance III BioSpin spectrometer. The physicochemical characteristics of methanol-heptane and methanol-octane mixtures were considered in combination with molecular dynamics simulation results. The conclusion was drawn that methanol was structured in mixtures with heptane at concentrations of 0.04-0.06 alkane mole fractions. This peculiarity was not observed in mixtures with other alkanes.
International Journal of Thermophysics, 2009
In this study experimental measurements of the thermophysical properties of binary mixtures containing hexane + aromatic hydrocarbon are continued. Here experimental data of the dynamic viscosity, η, at 298.15 K and atmospheric pressure, over the complete composition range are presented. As noted, the second compound of all mixtures belong to the same aromatic family, with a benzene ring having one ethyl chain or two methyl chains placed at different sites of the benzene ring. So, the molar mass for all four second compounds is exactly the same. Thus, these measurements will provide information about the influence of the methyl chain positions on the viscosity when it is mixed with hexane. From the measured values of the dynamic viscosity, dynamic viscosity deviations of the binary mixtures are determined and the viscosity deviations are compared with other deviation results for similar mixtures, and among the different binary mixtures.