Binary Liquid Mixture Research Articles

Density and viscosity of liquid mixtures formed by n-hexane, ethanol, and cyclopentyl methyl ether

Experimental determination, theoretical modeling, and molecular simulation have been combined to describe atmospherical density and viscosity for liquid n-hexane, ethanol, and cyclopentyl methyl ether pure compounds as a function of temperature and all the corresponding binary and ternary liquid mixtures at 298.15 K over the whole mole fraction range. Experimental determinations are carried out using a Stabinger viscosimeter. The reported density and viscosity data are modeled with the Statistical Associating Fluid Theory of Variable Range employing a Mie potential (SAFT-VR-Mie) equation of state coupled to the free volume theory (FVT). All-Atom molecular simulations employ equilibrium molecular dynamics (EMD) to obtain the corresponding densities from Isobaric-Isothermal (NPT) ensemble and viscosities from the microcanonical (NVE) and using the Green–Kubo formulation. According to the results, density and viscosity decrease with temperature for pure liquid fluids. For the case of liquid mixtures, densities and viscosities negatively deviate from the corresponding linear trend, and no ternary stationary points are detected under the explored conditions. The experimental data of both properties in binary mixtures are well correlated by a Redlich–Kister polynomial, and the ternary mixture is acceptably correlated by only using binary parameters. From a theoretical perspective, densities of binary and ternary mixtures are excellently predicted from the SAFT-VR-Mie EoS, whereas viscosities of the binary mixtures are well correlated from SAFT-VR-Mie EoS + FVT, while the viscosities of the ternary mixture are well predicted using the same framework. EMD accurately describes the density of pure fluids and mixtures, but it exhibits more significant deviations in viscosity predictions. Moreover, the qualitative viscosity trend with temperature and composition is maintained. Finally, SAFT-VR-Mie and EMD are used to describe the hydrogen bond (HB) network formed within the mixtures at different alcohol compositions, which is also used to validate the selected association scheme. HB formation varies with respect to ethanol concentration, and the results show a negative deviation from compositions linearity, showing good agreement between both approaches.

Influence of coolant and material properties on cooling high-temperature steel spheres in subcooled ethanol-water mixtures

The paper presents the new experimental results on cooling high-temperature steel spheres in subcooled ethanol-water mixtures at mass fractions of ethanol in the range of 10–80% under atmospheric pressure. Three test samples of 39 mm in diameter each have been prepared for the experiments: a carbon steel sphere with the oxidized surface and two stainless steel spheres. In the latter samples, one sphere had a polished surface, while the other one had a carbon coating. Usage of binary liquid mixtures as cooling liquids allows changing their thermophysical properties in a wide range. In general, when decreasing ethanol mass fraction boiling heat transfer intensifies, and it leads to an earlier (at higher surface temperature) transition to the intensive heat transfer regime. The experimental results are qualitatively consistent with a model that was proposed by authors earlier. This model describes the conditions of transition from a stable film boiling to an intensive heat transfer regime (so-called “microbubble boiling”). The main idea of the model is that this regime can arise due to the local contacts between the crests of the wavy liquid flow at the liquid/vapor interface and the protrusions of the surface roughness. The model considers the properties of a coolant (latent heat of evaporation, surface tension and kinematic viscosity) and thermophysical properties of a cooled surface (thermal effusivity). The experimentally obtained values of heat transfer coefficients in stable film boiling regimes are in agreement with the calculation results of the semi-empirical model of heat transfer in stable film boiling of subcooled liquids developed by authors earlier.

Neutrons in Softmatter

Neutron scattering is a powerful method to investigate hierarchical structure and dynamics of soft matter. In this article, several experimental results of surfactant systems, binary liquid mixtures with antagonistic salt, lipid membrane and hydration water by means of Small-Angle Neutron Scattering, Neutron Spin Echo and Quasi-Elastic Neutron Scattering were introduced.

Improving Force Field Accuracy by Training against Condensed-Phase Mixture Properties.

Developing a sufficiently accurate classical force field representation of molecules is key to realizing the full potential of molecular simulations as a route to gaining a fundamental insight into a broad spectrum of chemical and biological phenomena. This is only possible, however, if the many complex interactions between molecules of different species in the system are accurately captured by the model. Historically, the intermolecular van der Waals (vdW) interactions have primarily been trained against densities and enthalpies of vaporization of pure (single-component) systems, with occasional usage of hydration free energies. In this study, we demonstrate how including physical property data of binary mixtures can better inform these parameters, encoding more information about the underlying physics of the system in complex chemical mixtures. To demonstrate this, we retrain a select number of Lennard-Jones parameters describing the vdW interactions of the OpenFF 1.0.0 (Parsley) fixed charge force field against training sets composed of densities and enthalpies of mixing for binary liquid mixtures as well as densities and enthalpies of vaporization of pure liquid systems and assess the performance of each of these combinations. We show that retraining against the mixture data improves the force field's ability to reproduce mixture properties, including solvation free energies, correcting some systematic errors that exist when training vdW interactions against properties of pure systems only.

The effect of nano encapsulated phase change materials and nanoparticles on turbulent heat transport: A conical diffuser scenario

The present work investigates turbulent flow of single and hybrid nanofluids filled in a conical diffuser. The heat transfer coefficients and pressure losses are analyzed at various Reynolds numbers and nanoparticle volume fractions. The diffuser is filled with Al2O3, nano encapsulated phase change material NEPCM, and NEPCM_Al2O3 nanofluids. The thermophysical parameters of all nanofluids were determined using a novel methodology based on the thermodynamic equilibrium data for binary liquid mixtures. A notable novelty in the current work is the introduction of an innovative method of hybrid nanofluids composed of nanoparticles with and without phase change material (PCM). When compared to the other nanofluids tested, the NEPCM nanofluid presented the lowest pressure loss and the greatest heat transfer improvement within the diffuser. The Nusselt number of NEPCM nanofluids is enhanced by 15%, while for NEPCM_Al2O3 and Al2O3 nanofluids is increased by 10% and 6%, respectively. Similarly, the pressure drop is greater as compared to the base fluid, where the pressure drop is increased by 1%, 3.5%, and 5% for NEPCM, Al2O3, and NEPCM_Al2O3 nanofluid, respectively.

Acoustic and Viscometric Investigations of Aqueous D-Pantothenic Acid Calcium Hemi-salt

Abstract: Acoustic and viscometric measurements are increasingly being used to investigate the properties of pure components as well as the nature, strength, and order of intermolecular interactions between constituents in solution. The density (ρ), viscosity (n), and ultrasonic velocity (U) of aqueous D-Pantothenic acid hemi-calcium salt at 298.15K and 300.15K were measured. Various thermo -acoustic parameters such as adiabatic compressibility, free length (Lf), free volume (Vf), internal pressure, acoustic impedance (Z), Gibb's free energy (G), and molar sound velocity (R) have been calculated using experimentally measured data. Acoustic parameters are useful in understanding molecular interactions in binary liquid mixtures. Keywords; Ultrasonic velocity, Free length, acoustical parameters, Acoustic impedance.

Intrusion of liquids into liquid-infused surfaces with nanoscale roughness.

We present a theoretical study of the intrusion of an ambient liquid into the pores of a nanocorrugated wall w. The pores are prefilled with a liquid lubricant that adheres to the walls of the pores more strongly than the ambient liquid does. The two liquids are modeled as a binary liquid mixture of two species of particles, A and B. The mixture can decompose into a liquid rich in A particles, representing the ambient liquid, and another one rich in B particles, representing the liquid lubricant. The wall is taken to attract the B particles more strongly than the A particles. The ratio w-A/w-B of these interaction strengths is changed in order to tune the contact angle θ_{AB} formed by the A-rich/B-rich liquid interface between the two fluids and a planar wall, composed of the same material as the one forming the pores. We use classical density functional theory in order to capture the effects of microscopic details on the intrusion transition, which occurs as the concentration of the minority component or the pressure in the bulk of the ambient liquid is varied, moving away from bulk liquid-liquid coexistence within the single-phase domain of the A-rich bulk ambient liquid. These liquid structures have been studied as a function of the contact angle θ_{AB} and for various widths and depths of the pores. We also studied the reverse process in which a pore initially filled with the ambient liquid is refilled with the liquid lubricant. The location of the intrusion transition, with respect to its dependence on the contact angle θ_{AB} and the width of the pore, qualitatively follows the corresponding shift of the capillary-coexistence line away from the bulk liquid-liquid coexistence line, as predicted by a macroscopic capillarity model. Quantitatively, the transition found in the microscopic approach occurs somewhat closer to the bulk liquid-liquid coexistence line than predicted by the macroscopic capillarity model. The quantitative discrepancies become larger for narrower cavities. In cases in which the wall is completely wetted by the lubricant (θ_{AB}=0) and for small contact angles, the reverse transition follows the same path as for intrusion; there is no hysteresis. For larger contact angles, hysteresis is observed. The width of the hysteresis increases with increasing contact angle. A reverse transition is not found inside the domain within which the ambient liquid forms a single phase in the bulk once θ_{AB} exceeds a geometry-dependent threshold value. According to the macroscopic capillarity theory, for the considered geometry, this is the case for θ_{AB}>54.7^{∘}. Our computations show, however, that nanoscale effects shift this threshold value to much higher values. This shift increases strongly if the widths of the pores become smaller (below about ten times the diameter of the A and B particles).

Volumetric Properties of Binary Liquid Mixtures of Water with N-Methylpyrrolidone at (278.15–323.15) K and up to 70 MPa

Volumetric Properties of Binary Liquid Mixtures of Water with <i>N</i>-Methylpyrrolidone at (278.15–323.15) K and up to 70 MPa

Densities and excess volumes of binary and ternary mixtures of N, N-dimethyl sulfoxide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone at T = (293.15, 313.15)K and atmospheric pressure

Densities of binary liquid mixtures of N,N-dimethyl acetamide (DMA) + dimethyl sulfoxide (DMSO), DMSO + N - methyl-2-pyrrolidone (NMP), and DMA + NMP were measured over the entire composition range in the temperatures of 293.15 K and 313.15 K at atmospheric pressure. Based on this measurements, density deviations, Δρ, and excess molar volumes, V E , of binary mixtures were calculated and the same were fitted by Redlich-Kister equation. Binary adjustable parameters were obtained using Linear Least Squares Regression (Microsoft Excel 2016). The variations of derivative properties with temperature and composition were discussed. The densities of ternary mixtures DMSO + DMA + NMP were measured at 293.15 K and 313.15 K. According to experimental data, diagrams of density isolines at both temperature, density changes and excess molar volume at 293.15 K are constructed.

Study on Thermodynamic and Transport Properties of Binary Liquid Mixtures (N-Methylformamide with Aniline, N-Methylaniline, and N,N-Dimethylaniline) at Various Temperatures

Study on Thermodynamic and Transport Properties of Binary Liquid Mixtures (N-Methylformamide with Aniline, N-Methylaniline, and N,N-Dimethylaniline) at Various Temperatures

Research Progress on Polyaniline-Ionic liquids for Long Cycle-Stable Supercapacitors with High Capacitance

Ionic liquids have been used either as polymerization medium or as electrolytes for polyaniline (PANI) electrodes to produce long cycle-stable supercapacitors with high capacitance. As a polymerization medium, ionic liquids play the role of a soft template agent and induce the formation of nanostructured PANI morphology. Nanorod, nanowire, or spherical PANI morphology has been obtained in ionic liquids instead of agglomerated particles resulted in the conventional media. The well-defined one-dimensional PANI morphology ensures a short charge transfer distance in the PANI materials and low contact resistance between PANI and electrolyte interfaces. The efficiency of ionic liquids as a soft template agent is related to their structure as well as to their proportion in the reaction medium. As electrolytes, “neat” ionic liquids provide low but stable specific capacitance of PANI over more than hundreds of cycles. Binary mixtures of ionic liquids and solvents (e.g. acetonitrile, water) have increased both the specific capacitance and the capacitance retention of PANI compared with the performances resulting in the conventional aqueous acid electrolytes. Using ionic liquids to carry out both the synthesis and the electrochemical characterization of PANI is an effective approach to improve PANI cycle life. The key parameter is to choose the convenient ionic liquids. This review covers the most significant studies conducted on PANI/ionic liquids for supercapacitor applications.

Predicting nonlinear physical aging of glasses from equilibrium relaxation via the material time.

The noncrystalline glassy state of matter plays a role in virtually all fields of materials science and offers complementary properties to those of the crystalline counterpart. The caveat of the glassy state is that it is out of equilibrium and therefore exhibits physical aging, i.e., material properties change over time. For half a century, the physical aging of glasses has been known to be described well by the material-time concept, although the existence of a material time has never been directly validated. We do this here by successfully predicting the aging of the molecular glass 4-vinyl-1,3-dioxolan-2-one from its linear relaxation behavior. This establishes the defining property of the material time. Via the fluctuation-dissipation theorem, our results imply that physical aging can be predicted from thermal-equilibrium fluctuation data, which is confirmed by computer simulations of a binary liquid mixture.

Binary mixtures of homologous room-temperature ionic liquids: Nanoscale structure evolution with alkyl lengths’ difference

The nanoscale structure of equimolar binary mixtures [C12mim]0.5[Cnmim]0.5[NTf2] was studied by small-angle X-ray scattering for n=1-22 and T=293-373 K. All mixtures exhibit local layering and layer-normal thermal contraction with increasing T, as found for the pure components. The layer-parallel spacings of the polar headgroups and of the alkyl chains vary minimally with n over the full n range. The layer-normal spacing dI at high n follows closely, with a 1–1.5 Å downshift, the increasing trend of the pure longer component’s dI, indicating its dominance of the layering. At low n,dI at n=1 greatly exceeds dI of the pure longer component, n=12, and decreases sharply with increasing n, indicating a structure akin to lipid bilayer solutions. At intermediate n,dI is roughly constant, lying 1–1.5 Å below dI of n=12. Our layer spacings provide a near-unique opportunity to study the evolution over a wide n-range of the normalized dI’s molecular-scale deviation from ideality, yielding a linear dependence on the normalized n-difference squared. This may be related to the same-dependence interchange energy due to chain length mismatch, dominating binary alkane and alcohol mixtures. Finally, our dI also show the power P of the modified Vegard’s Law to be linear in the mixtures’ normalized n-mismatch, albeit with different low- and high-n slopes.

Comprehensive evaluation of 3A, 4A, 5A, and 13X zeolites for selective 1-octene adsorption over n-octane

Among linear α-olefins, 1-octene is widely used as a starting material in the industrial production of plastics, oils, waxes, and surfactants. The adsorption separation of gaseous olefin/paraffin using various adsorbents has been extensively studied; however, detailed studies on the adsorption separation of liquid-phase olefin/paraffin are scant. In this study, we systematically investigated the selective adsorption of 3A, 4A, 5A, and 13X bead-shaped zeolites from 1-octene/n-octane liquid binary mixture as a function of type and weight of the zeolites. Batch-type adsorption experiments were performed in the 1-octene volume fraction range of 10–90 %. The results show that 5A and 13X zeolites are promising adsorbents for selective 1-octene adsorption owing to the preferential adsorption of 1-octene on the cation sites in the micropore. Contrastingly, both 1-octene and n-octane cannot enter 3A and 4A micropores, resulting in negligible preferential adsorption of 1-octene over n-octane. The Langmuir constant of 5A is higher than that of 13X due to the stronger polarization effect of Ca2+ compared to that of Na+, resulting in additional attractive interaction between the adsorbent and 1-octene. The experimental analysis presented in this study provides a solid basis for the development of selective adsorbents for the liquid–liquid separation.

An improved correlation for thermophysical properties of binary liquid mixtures

This paper presents an improved correlation for thermophysical properties of binary mixtures. The new correlation permits calculation of excess properties and property deviations, and it has the capability of correlating and predicting different functional forms of the thermophysical properties within the experimental uncertainties. This paper contains examples for: molar volume, kinematic and dynamic viscosity, surface tension, refractive index, heat capacity and thermal conductivity.

Studies of Mixing Properties of Binary Systems of 2-Butoxy Ethanol with Amines at 298.15, 303.15, and 308.15 K

The nature of interaction of binary liquid mixtures of 2-butoxy ethanol with amines, namely, diisopropylamine, dibutylamine, and tributylamine, has been examined using the experimentally measured values of density (ρ), ultrasonic speed (u), and viscosity (η) over the temperature range from 298.15 to 308.15 K, in the present discussion. Using the experimentally measured values, various excess and deviation properties have been evaluated and discussed in terms of interaction among the studied binary mixtures. Strong intermolecular interaction among unlike components of binary mixtures is confirmed by these calculated properties. The order of the magnitude of these properties gives an insight into the order of interaction of mixtures of 2-butoxy ethanol with amines. Excess and deviation properties have been correlated with composition using the Redlich–Kister polynomial. The correlation ability of various viscosity models has also been compared. The Fourier transform infrared spectra of these liquid mixtures have also been studied at room temperature.

Intensification of isobutane/1-butene alkylation process in a micromixing microreactor catalyzed by ILs/H2SO4

The products of isobutane/butene alkylation are ideal high-octane blending components of gasoline pool. Binary mixtures of acidic imidazolium ionic liquids [CnMIm][OTf] (n = 4, 6, 8) and H2SO4 were used to catalyze isobutane/butane alkylation in a microreactor integrated with staggered herringbone grooves. The mixing behaviors of acid and hydrocarbons were simulated in the microchannel configured with micromixing elements by computational fluid dynamics (CFD) simulation. [CnMIm][OTf]/H2SO4 showed better catalytic performance than H2SO4 solely. Especially the [OMIm][OTf]/H2SO4 showed excellent performance. In the designed microreactor, the alkylate with research octane number (RON) of 99.5 was obtained at 10.0°C and reaction time of 81 s with [OMIm][OTf]/H2SO4 as catalyst. The results are better than currently available research works implemented in batch reactors. The catalyst [OMIm][OTf]/H2SO4 was recycled 14 times without reducing the catalytic activity. It indicates that the composite catalysts possess excellent reutilization performance.

Study of Acoustic Behaviour of Thiamin Hydrochloride with Methanol at 303K

Abstract: In the present study, ultrasonic velocity (u), density (ρ) and viscosity (η) have been measured at 2 MHz frequency in the binary mixtures of thiamin hydrochloride and methanol in the concentration range 0 to 0.1 molar concentration at 303K using ultrasonic interferometer technique. From the basic experimental data, various acoustic and thermodynamic parameters; namely, adiabatic compressibility, free length, free volume and internal pressure, were calculated, with a view to investigate the nature and strength of molecular interaction in the binary liquid mixture of thiamin hydrochloride and methanol. The obtained results support the occurrence of molecular interaction through hydrogen bonding in the binary liquid mixture. Keywords: Ultrasonic velocity, Binary liquid mixture, Molecular interaction, Hydrogen bonding.

Dual-band measurement of complex permittivity in a microwave waveguide with a flexible, thin and sensitive metamaterial-based sensor

A dual-band metamaterial-based sensor is proposed to determine the complex dielectric constant of ethanol-methanol mixtures. The original sensor structure incorporates one connected dual H-shaped slot resonators at the center and one H-shaped slot resonator at the left and right sides of a rectangular copper patch to provide two distinct resonance frequencies. Polycarbonate is chosen as the substrate material due to its lightness, flexibility, robustness and transparency. Full-wave simulations of electric field distributions reveal that the dual resonances at 3.7 GHz and 4.6 GHz stem from different parts of the metamaterial. Measurements are carried out with a WR-229 microwave waveguide and the electromagnetic simulation results are confirmed with good agreement. A first-order equation that relates the complex dielectric constant to the shift of resonance frequency and peak attenuation is used to determine the complex dielectric constant of ethanol-methanol mixtures in the vicinity of 3.3 GHz and 4.4 GHz frequencies. A good agreement with the literature values is obtained validating the accuracy of the used model. Experimental results revealed that the frequency detection resolution and sensitivity parameter values of the proposed sensor are 25.3 MHz and 0.73% for the lower-frequency band and 9.6 MHz and 0.22% for the higher-frequency band, respectively. In addition to being able to operate at dual frequencies, the proposed metamaterial-based sensor has high sensitivities for the two resonance frequencies. Moreover, the advantages of the proposed sensor, as being electrically-small, flexible, noncontact and reusable, provide a good option for discrimination of binary liquid mixtures at multiple frequencies.

Study of short range and long range molecular interactions in binary liquid mixtures of N,N-dimethylformamide (DMF) and 1-propanol

In the present study precisely measured properties; static dielectric constant (ε0), refractive index (n) and density (ρ) of binary liquid mixtures of N,N-dimethylformamide (DMF) and 1-propanol (1-PN) have been used to determine linear correlation parameter (grr), mutual linear correlation parameter (gAB), excess Helmholtz free energy functions (ΔF) and excess molar polarization (ΔP). The dipolar contributions to these functions arising from long range electrostatic interaction, short range interaction between identical molecules and short range interaction between dissimilar molecules have been assessed separately. The excess thermodynamic functions calculated from the experimental data supports the formation of clusters with antiparallel or destructive angular correlation (β-clusters). The variation of excess static dielectric constant, excess refractive index and excess molar volume have been used to discuss the type, the strength and the nature of intermolecular interactions betweenconstituent species. Comparison of the predicted values of static dielectric constant and refractive index of the liquid mixtures using various mixing rules with the experimentally determined values have been assessed in terms of Average Percentage Deviation (APD).