Excess molar volumes and deviation in viscosities of binary liquid mixtures of acrylic esters with hexane-1-ol at 303.15 and 313.15 K

Densities and viscosities for the four binary liquid mixtures of methyl acrylate, ethyl acrylate, butyl acrylate and methyl methacrylate with hexane-1-ol at temperatures 303.15 and 313.15 K and at atmospheric pressure were measured over the entire composition range. These values were used to calculate excess molar volumes and deviation in viscosities which were fitted to Redlich–Kister polynomial equation. Recently proposed Jouyban Acree model was also used to correlate the experimental values of density and viscosity. The mixture viscosities were correlated by several semi-empirical approaches like Hind, Choudhary–Katti, Grunberg–Nissan, Tamura and Kurata, McAllister three and four body model equations. A graphical representation of excess molar volumes and deviation in isentropic compressibility shows positive nature whereas deviation in viscosity shows negative nature at both temperatures for all four binary liquid mixtures. Positive values of excess molar volumes show that volume expansion is taking place causing rupture of H-bonds in self associated alcohols. The results were discussed in terms of molecular interactions prevailing in the mixtures.     

Prediction of viscosities of hydrocarbon mixtures

A new model for prediction of the viscosities of hydrocarbons including oil and gas mixtures is presented. The model is based on the principle of corresponding states with methane and decane as reference components. The viscosity of a given component or mixture is determined from the reduced viscosities of the reference components using the molecular weight as an interpolation parameter.

The model has been used for prediction of viscosities of both pure components and mixtures over large pressure ranges and for reduced temperatures above 0.476. The results are in good agreement with the experimental data. The new model compares favorably with earlier published methods, which use only one reference component.

Finally, the model has been tested on data for 6 oil mixtures from the North Sea. The mean deviation based on 34 experimental points was 6.4 %.     

Correlation of viscosity of binary liquid mixtures

A new two-parameter model presented in the previous work for correlating the viscosity of pure liquids is extended to correlate the viscosity of binary liquid mixtures. The correlation relates this non-equilibrium property to some equilibrium properties, the volume, the internal energy of vaporization and their excess properties. The viscosities of 47 binary liquid mixtures, including different kinds, which having no maximum or minimum viscosity, which having one maximum or one minimum viscosity, and which having both of one maximum and one minimum viscosities in the whole composition range, are correlated using the model and compared with data reported in the literature with the overall average absolute deviation of 1.05%. Further comparison with a good correlation, a free-volume type correlation, is also discussed. The results show that the new method is satisfactory.     

Viscosity Investigations on the Binary Systems of (1 ChCl:2 Ethylene Glycol) DES and Methanol or Ethanol

In this study, the viscosity behavior of two mixtures of Ethaline (1 ChCl:2 ethylene glycol) with either methanol or ethanol were investigated over the temperature range of 283.15–333.15 K at atmospheric pressure. The measured viscosities of neat Ethaline, methanol, and ethanol showed reliable agreement with the corresponding reported literature values. The mixture viscosities were modeled by an Arrhenius-like model to determine the behavior of viscosity with respect to temperature. The data were also modeled by the four well-known mixture viscosity models of Grunberg–Nissan, Jouyban–Acree, McAllister, and Preferential Solvation. All of the model results were reliable, with the Jouyban–Acree and Preferential Solvation models showing the most accurate agreement with the experimental measurements. The Jones–Dole viscosity model was also investigated for the measured viscosities, and by analyzing the results of this model, strong interactions among Ethaline and the alcohol molecules were proposed for both systems. As a final analysis, viscosity deviations of the investigated systems were calculated to study the deviations of the viscosity behaviors with respect to ideal behavior. Both systems showed negative viscosity deviations at all of the investigated temperatures, with the negative values tending towards zero, and hence more ideal behavior, with increasing temperatures. Moreover, in order to correlate the calculated viscosity deviations, the Redlich–Kister model was successfully used for both systems and at each investigated temperature.     

Volumetric and viscosity properties of {propyl propanoate (1) + heptane (or octane) (2)} mixtures at several temperatures and correlation with the Jouyban–Acree model

Densities and viscosities of binary liquid mixtures of propyl propanoate + heptane and propyl propanoate + octane at temperatures of 278.15, 283.15, 288.15, 293.15, 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15 K have been measured at atmospheric pressure over the entire range of composition. Using these experimental data, the excess molar volumes and the viscosity deviation have been calculated. The experimental data of density and viscosity at different investigated temperatures were mathematically represented by the Jouyban–Acree model. The mean relative deviation (MRD) was used as an error criterion, and the MRD values for data correlation of density and viscosity at different investigated temperatures are less than 0.03% and 0.50%, respectively. Excess molar volumes and viscosity deviations were correlated with Redlich–Kister equation. The calculated data point out the absence of speci?c interactions between the molecules of different components, which would be slightly weaker compared to the interactions in the pure components.     

Mathematical representation of solubility of electrolytes in binary solvent mixtures using Jouyban-Acree model

Applicability of a solution model for calculating salt's solubility in binary solvent mixtures was shown. The accuracy of the proposed model was evaluated by computing mean percentage deviation (MPD) employing available solubility data of electrolytes in binary solvents at various temperatures from the literature. The overall MPD (+/-S.D.) for correlation of solubility data was 4.7+/-5.1% and for prediction using model trained by a minimum number of experimental data points was 10.5+/-12.5%.     

High-temperature liquid chromatography. Part II: Determination of the viscosities of binary solvent mixtures—Implications for liquid chromatographic separations

This paper is the second in a series of consecutive publications, explaining the concept of high temperature liquid chromatography under various important aspects. The second publication deals with the determination of the viscosity of binary solvent mixtures used in reversed phase liquid chromatography in a temperature range between 25 and 250 °C. In literature, only limited data of the temperature dependent viscosities of liquid solvents or binary solvent mixtures can be found. Therefore, the viscosities of the pure solvents as well as the binary mixtures had to be determined experimentally up to 250 °C. The viscosity data were used to estimate the pressure drop in a capillary connecting a high-temperature HPLC system with a mass spectrometer. The solvent perturbation could be avoided by adjusting the diameter of the transfer capillary to the viscosity and vapour pressure of the mobile phase. The viscosity data were also used to show that a significant gain in analysis speed is theoretically feasible. This factor clearly depends on the nature of the solvent system, because for mixtures with a large viscosity maximum at ambient temperature, this effect is most pronounced.     

Correspondence Between Grunberg–Nissan, Arrhenius and Jouyban–Acree Parameters for Viscosity of Isobutyric Acid?+?Water Binary Mixtures from 302.15 to 313.15?K

The study of physical properties of binary liquid mixtures is of great importance for understanding and characterizing intermolecular interactions. Similarly, some models attempt to correlate viscosity in liquid mixtures in order to illuminate interacting structures and peculiar behaviors. Grunberg?CNissan parameters for viscosity (??) in isobutyric acid?+?water mixtures over the entire range of mole fractions under atmospheric pressure and from 302.15 to 313.15?K were calculated from experimental dynamic viscosities presented in previous works. Many experimenters investigate physicochemical properties using various models to develop interpretations and conclusions. The present work comes within the framework of correlating different equations. Relationships between the Grunberg?CNissan and Arrhenius and Jouyban?CAcree parameters for viscosity are shown in one critical binary mixture.     

An equation-of-state-based viscosity model for non-ideal liquid mixtures

A viscosity model based on the Eyring’s theory and a cubic equation of state (Peng–Robinson–Stryjek–Vera) has been applied to the correlation and prediction of experimental liquid viscosities of binary mixtures containing polar fluids within a wide range of temperature, pressure and composition (encompassing low-pressure and compressed liquid conditions). Highly non-idealities of the binary mixtures considered in this study were conveniently handled via the application of the Wong–Sandler approach for the mixing rules used in the cubic equation of state. The results obtained were highly satisfactory for various non-ideal binary mixtures over the whole composition range at a low pressure. The predictive capabilities of the present approach were also verified in the representation of liquid viscosities at elevated pressures preserving the same model parameters previously obtained at low pressure.     

Generalized correlation for predicting the kinematic viscosity of liquid petroleum fractions

A two-parameter viscosity model proposed previously for pure liquids is extended to correlate the kinematic viscosity–temperature behavior for liquid petroleum fractions. The coefficients in the viscosity equation are related to the characterization properties of the petroleum fractions and a generalized kinematic viscosity–temperature correlation is then developed, which needs only specific gravity at 15.6°C and 50% boiling point as input parameters. The present method, when tested by predicting the experimental kinematic viscosities of 47 fractions from 15 world crude oils with total 250 data points, yielded reasonable results with an overall average absolute deviation of 4.2%.     

Experimental densities,dynamic viscosities and surface tensions of the ionic liquids series 1-ethyl-3-methylimidazolium acetate and dicyanamide and their binary and ternary mixtures with water and ethanol at T = (298.15 to 343.15 K)

In this paper, experimental densities and dynamic viscosities of 1-ethyl-3-methylimidazolium based ionic liquids (ILs) with the anions acetate and dicyanamide are presented in a wide temperature range (298.15 to 343.15 K) at atmospheric pressure. Surface tension of these ILs was measured at T = 298.15 K. The effect of water and/or ethanol compositions on densities and dynamic viscosities of these ILs are studied in binary and ternary mixtures. A quadratic mixing rule was used to correlate binary and ternary liquid densities. The Eyring–Patel–Teja model, which is recommended for polar and aqueous systems, is used to correlate dynamic viscosity data over the whole range of compositions and temperatures in binary and ternary mixtures. Temperature-dependent interaction parameters are introduced here to account for the changes of viscosities with temperature showing good agreements with experimental data.     

Transport properties of CO2-expanded acetonitrile from molecular dynamics simulations

Carbon-dioxide-expanded liquids, which are mixtures of organic liquids and compressed CO2, are novel media used in chemical processing. The authors present a molecular simulation study of the transport properties of liquid mixtures formed by acetonitrile and carbon dioxide, in which the CO2 mole fraction is adjusted by changing the pressure, at a constant temperature of 298 K. They report values of translational diffusion coefficients, rotational correlation times, and shear viscosities of the liquids as function of CO2 mole fraction. The simulation results are in good agreement with the available experimental data for the pure components and provide interesting insights into the largely unknown properties of the mixtures, which are being recognized as important novel materials in chemical operations. We find that the calculated quantities exhibit smooth variation with composition that may be represented by simple model equations. The translational and rotational diffusion rates increase with CO2 mole fraction for both the acetonitrile and carbon dioxide components. The shear viscosity decreases with increasing amount of CO2, varying smoothly between the values of pure acetonitrile and pure carbon dioxide. Our results show that adjusting the amount of CO2 in the mixture allows the variation of transport rates by a factor of 3-4 and liquid viscosity by a factor of 8. Thus, the physical properties of the mixture may be tailored to the desired range by changes in the operating conditions of temperature and pressure.     

Viscosity of ionic liquid mixtures of 1-alkyl-3-methylimidazolium hexafluorophosphate + CO2

The viscosities of the mixtures 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM][PF₆]) + CO₂ and 1-octyl-3-methylimidazolium hexafluorophosphate ([OMIM][PF₆]) + CO₂ were measured with a rolling ball viscometer. The CO₂ mole fraction for one mixture ranged up to 0.434 and the other up to 0.447. The viscosities were measured at 293.15-353.15 K and 10-20.0 MPa. The experimental uncertainty in viscosity was estimated to be within ±3.0%. The experimental data were compared with McAllister's three-body model, which correlated with the experimental data within average absolute deviations of 5.9%.     

Modeling the thermodynamic and transport properties of decahydronaphthalene/propane mixtures: Phase equilibria, density, and viscosity

The density and viscosity of propane mixed with 66/34 trans/cis-decahydronaphthalene were measured over a wide range of temperatures (323-423 K), pressures (2.5-208 bar), and compositions (0-65 mol% propane). For conditions giving two phases, the composition of the dense phase was measured in addition to the density and viscosity. The modified Sanchez-Lacombe Equation of State (MSLEOS) was used with a single linearly temperature-dependent pseudo-binary interaction parameter to correlate the phase compositions and densities. The compositions and densities of the mixtures were captured well with absolute average deviations between the model and the data of 5.3% and 2.3%, respectively. The mixture viscosities were computed from a free volume model (FVM) by using a single constant binary interaction parameter. Density predictions from the MSLEOS were used as input mixture density values required for the FVM. The FVM was found to correlate well with the mixture viscosity data with an absolute average deviation between the model and the data of 5.7%.     

Influence of pressure and temperature on the physico-chemical properties of mobile phase mixtures commonly used in high-performance liquid chromatography

To fulfil the increasing demand for faster and more complex separations, modern HPLC separations are performed at ever higher pressures and temperatures. Under these operating conditions, it is no longer possible to safely assume the mobile phase fluid properties to be invariable of the governing pressures and temperatures, without this resulting in significantly deficient results. A detailed insight in the influence of pressure and temperature on the physico-chemical properties of the most commonly used liquid mobile phases: water-methanol and water-acetonitrile mixtures, therefore becomes very timely. Viscosity, isothermal compressibility and density were measured for pressures up to 1000 bar and temperatures up to 100 degrees C for the entire range of water-methanol and water-acetonitrile mixtures. The paper reports on two different viscosity values: apparent and real viscosities. The apparent viscosities represent the apparent flow resistance under high pressure referred to by the flow rates measured at atmospheric pressure. They are of great practical use, because the flow rates at atmospheric pressure are commonly stable and more easily measurable in a chromatographic setup. The real viscosities are those complying with the physical definition of viscosity and they are important from a fundamental point of view. By measuring the isothermal compressibility, the actual volumetric flow rates at elevated pressures and temperatures can be calculated. The viscosities corresponding to these flow rates are the real viscosities of the solvent under the given elevated pressure and temperature. The measurements agree very well with existing literature data, which mainly focus on pure water, methanol and acetonitrile and are only available for a limited range of temperatures and pressures. As a consequence, the physico-chemical properties reported on in this paper provide a significant extension to the range of data available, hereby providing useful data to practical as well as theoretical chromatographers investigating the limits of modern day HPLC.     

Viscosity dependence of the kinetic parameters of the radical ion pair in homogeneous solution determined by optically detected X- and ku-band electron spin resonance

We investigated the dynamics of the radical ion pairs formed by photoinduced electron-transfer reaction from zinc tetraphenyl porphyrin to 2-methyl-1,4-naphthoquinone in mixtures of 2-propanol and cyclohexanol. By the irradiation of a resonant X- (9.16 GHz) or Ku-band (17.41 GHz) microwave pulse, the time profiles of the transient absorptions was modified and the yields of escaping radical ions decreased. From these experiments, we determined the kinetic parameters of the radical ion pairs at various solvent viscosities. The recombination rates of the singlet pairs were (4 +/- 4), (8 +/- 3), and (16 +/- 3) x 10(6) s(-1) at 5, 10, and 15 cP, respectively. The escape rates were (1.7 +/- 0.2), (1.4 +/- 0.1), and (0.9 +/- 0.2) x 10(6) s(-1) at 5, 10, and 15 cP, respectively. The viscosity dependence of the kinetic parameters was followed by the simple continuum diffusion model.     

Thermodynamic Properties of Binary Mixtures of the Amino Acid Ionic Liquids [Bmim][Glu] or [Bmim][Gly] with Methanol at T=298.15 to 313.15 K

Densities, viscosities and refractive indices were determined for two ionic liquid mixtures formed by the 1-butyl-3-methylimidazolium glutamic acid salt ([Bmim][Glu]) or the 1-butyl-3-methylimidazolium glycine acid salt ([Bmim][Gly]), respectively, with methanol over the mole fraction from 0.1 to 0.9 and at temperatures ranging from 298.15 K to 313.15 K at intervals of 5 K and at atmospheric pressure. Excess molar volumes, viscosity deviations and refractive index deviations have been calculated from the experimental data and fitted to a Redlich–Kister polynomial function. The results have been interpreted in terms of ion-dipole interactions, and structural factors of the ionic liquid and alcohol molecular liquids.     

Correspondence between Grunberg-Nissan,Arrhenius and Jouyban-Acree parameters for viscosity of 1,4-dioxane + water binary mixtures from 293.15 K to 320.15 K

The study of physical properties of binary liquid mixtures is of great importance for understanding and characterisation of molecular interactions. In the same way, some models attempt to correlate viscosity in liquid mixtures to release eventual interactions, structures’ change and peculiar behaviours. Grunberg–Nissan (GN) parameters for viscosity (η) in 1,4-dioxane?+?water mixtures over the entire range of mole fractions under atmospheric pressure and from 293.15?K to 320.15?K were calculated from experimental dynamic viscosities presented in previous works. Many experimenters investigate physicochemical properties using numerous models to derive some interpretations and conclusions. The present work comes within the framework of correlating different used equations to restrict investigations with an optimal of number of these models. Relationship between the GN, Arrhenius and Jouyban–Acree parameters for viscosity is shown in one binary mixture which dielectric constants of their pure components are very distinct.     

Synthesis and Characterization of Heat-Resistant Polyamides from Thiadiazacycloheptatriene Dicarboxylic Acid

Novel polyamides containing 2,3,6,7-dibenzo-1-thia-4,5-diazacy-clohepta-2,4,6-triene-4′,4″-dicarboxy-l, l-dioxide (VII) are reported. The acid VII was prepared in several steps from p-chlorobenzoic acid and characterized by spectral data and elemental analysis. Prior to polymer synthesis, a model diamide (MDA) was prepared from VII and p-toluidine. The model diamide and several polyamides were obtained in an overall yield of (75-90%) by direct polycondensation of acid VII with certain diamines through a phosphorylation reaction at 100-110°C employing a solvent mixture of NMP-pyridine. The resulting polyamides and MDA were characterized by spectral, analytical, and thermal methods. The solubility, density, viscosity, and morphology (X-ray) were also studied for the polyamides. These polymers were moderately soluble in conventional polymer solvents, and the inherent viscosities were measured in concentrated sulfuric acid. Integral procedural decomposition temperatures (ipdt) were calculated from their primary thermogram in the temperature range 100-650°C in order to have quantitative data regarding their relative thermal stabilities. The polymers exhibit a 10% weight loss at 500°C in static air.     

Correlation of viscosities of pure liquids in a wide temperature range

On the basis of Eyring's absolute rate theory, a new two-parameter model is presented for correlating the viscosity data of pure saturated liquids in a wide temperate range. The correlation relates the viscosity, a non-equilibrium property, to equilibrium properties. The parameters in the new correlation can be easily determined through a few viscosity data and a knowledge of the vapor pressure, the saturated liquid volume and the heat of vaporization. The viscosities of 106 pure compounds, including polar, nonpolar, organic and inorganic liquids with total 1473 data points are correlated using this model and compared with data reported in the literature, and the overall average deviation is 1.51%. The results show that the correlation with the new model is satisfactory.