Behavior Of Binary Liquid Mixtures Research Articles

Binding potential and wetting behavior of binary liquid mixtures on surfaces.

We present a theory for the interfacial wetting phase behavior of binary liquid mixtures on rigid solid substrates, applicable to both miscible and immiscible mixtures. In particular, we calculate the binding potential as a function of the adsorptions, i.e., the excess amounts of each of the two liquids at the substrate. The binding potential fully describes the corresponding interfacial thermodynamics. Our approach is based on classical density functional theory. Binary liquid mixtures can exhibit complex bulk phase behavior, including both liquid-liquid and vapor-liquid phase separation, depending on the nature of the interactions among all the particles of the two different liquids, the temperature, and the chemical potentials. Here we show that the interplay between the bulk phase behavior of the mixture and the properties of the interactions with the substrate gives rise to a wide variety of interfacial phase behaviors, including mixing and demixing situations. We find situations where the final state is a coexistence of up to three different phases. We determine how the liquid density profiles close to the substrate change as the interaction parameters are varied and how these determine the form of the binding potential, which in certain cases can be a multivalued function of the adsorptions. We also present profiles for sessile droplets of both miscible and immiscible binary liquids.

Thermodynamic study for the (butyl, hexyl and octyl) acetoacetate under high pressure CO2

Understanding the phase behavior of binary liquid mixtures containing butyl acetoacetate, hexyl acetoacetate, and octyl acetoacetate under high-pressure supercritical CO2 (sc-CO2) is essential for several applications. The solubility curves for these binary mixtures have been investigated at different temperature and pressure ranges, specifically between 313.2 K and 393.2 K and 2.39 MPa to 23.83 MPa. The three systems, namely butyl acetoacetate, hexyl acetoacetate, and octyl acetoacetate in high-pressure sc-CO2, exhibit critical mixture curves and a maximum in pressure–temperature (P, T) diagrams between the critical point of butyl acetoacetate/hexyl acetoacetate/octyl acetoacetate and carbon dioxide. These characteristics of the critical mixture plot fall under the category of type-I behavior.The Peng-Robinson equation, which utilizes van der Waals mixing rules and two interaction parameters, is employed to correlate experimental solubility curves and critical mixture curves of the aforementioned three systems. The root mean square deviation percentage (RMSD%) is calculated at each temperature (using temperature-dependent adjusted parameters) for the butyl acetoacetate + sc-CO2, hexyl acetoacetate + sc-CO2, and octyl acetoacetate + sc-CO2 systems, and it ranges from 3.11% to 5.92%, 2.09% to 3.97%, and 1.70% to 3.02%, respectively.

Demonstration of Solute-specific Synergism in Binary Solvents.

The structure and solvation behavior of binary liquid mixtures of Methanol (MeOH) and N, N-Dimethylformamide (DMF) are explored by ascertaining their intermolecular interactions with either Rhodamine-B (RhB) or Rhodamine101 (Rh101) dye through steady-state absorption, emission, and two-photon induced fluorescence. Specifically, in the present investigation, we examine the strong synergistic solvation observed for the combinations of hydrogen bond donating (MeOH) and accepting (DMF) solvent pairs. Solvatochromism causes the solvatochromic probe molecules to sense increased polarity compared to their bulk counterparts. The origin of synergism was explained in terms of solute-solvent and solvent-solvent interactions in binary solvent mixtures interactions, as evidenced by probe dependence. The solvation behavior of the Methanol and DMF binary solvent mixture shows strong probe dependence, with Rh101 showing synergism while RhB does not.

Studies on the interactional behaviour of binary liquid mixtures of tripropylene glycol monomethyl ether and butyl amines at different temperatures

In the present study densities, ρ, and speeds of sound u, have been measured for the binary mixtures of tripropylene glycol monomethyl ether with butyl amine, dibutyl amine, and tributyl amine across the entire composition range at temperatures T = (288.15, 293.15, 298.15, 303.15, 308.15) K and experimental pressure p = 0.1 MPa. Experimental densities and speeds of sound data has been used to determine excess molar volumes, isentropic compressibility, molar isentropic compressibility KS,m and its excess counterpart excess molar isentropic compressibility. Deviations in intermolecular free length and deviations in acoustic impedance have also been determined. Further we have also calculated the partial molar volumes for binary mixtures at different temperatures. The variation of these determined parameters with temperature and composition has been discussed with a view to understand molecular interactions present in the binary liquid mixtures of alkoxypropanol and butyl amines. The experimental data has also been fitted with Jouyban-Acree model.

Insights into adsorption behaviour of binary liquid mixtures in porous media using fast field cycling NMR

Fast field cycling, FFC, NMR relaxometry experiments are reported in the frequency range of 10 kHz–40 MHz to characterise the adsorption behaviour of cyclohexane:THF (non-polar:polar) and THF:methanol (polar:polar) binary liquid mixtures adsorbed on a γ-alumina surface of catalytic interest. Laplace inversion of the relaxation rate data is employed to identify the chemical species in the binary mixture. In both systems studied, the more polar molecule preferentially interacts with the surface compared to the co-imbibed species. The relaxation rate data were analysed to explore the relative influences of surface dynamics and surface accessibility on the observed relaxation rates. For both binary systems, the change in relaxation behaviour with composition is interpreted as a change in the surface accessibility of each species caused by a micro-phase separation at the pore surface.

Probing Intermolecular Interactions in Binary Liquid Mixtures Using Femtosecond Laser-Induced Self-Defocusing

Photo-thermal behavior of binary liquid mixtures has been studied by high repetition rate (HRR) Z-scan technique with femtosecond laser pulses. Changes in the peak-valley difference in transmittance (ΔTP-V) for closed aperture Z-scan experiments are indicative of thermal effects induced by HRR femtosecond laser pulses. We show such indicative results can have a far-reaching impact on molecular properties and intermolecular interactions in binary liquid mixtures. Spectroscopic parameters derived from this experimental technique show that the combined effect of physical and molecular properties of the constituent binary liquids can be related to the components of the binary liquid.

Liquid–Liquid Phase Behavior of Solutions of 1,3-Dimethylimidazolium- and 1-Methyl-3-propylimidazolium Bis((trifluoromethyl)sulphonyl)amide (C1,3mimNTf2) in n-Alkyl Alcohols

The phase behavior of binary liquid mixtures of the ionic liquids (ILs) 1,3-dimethylimidazolium bis((trifluoromethyl) sulfonyl) amide (C1mimNTf2) and 1-methyl-3- propyl imidazolium bis ((trifluoromethyl) sulfonyl) amide (C3mimNTf2) with n-alkyl alcohols (CnOH; 3 ≤ n ≤ 8) was investigated. The phase diagrams are obtained by applying the cloud-point method on a set of synthetically prepared samples. Partial miscibility with an upper critical solution temperature (UCST) was observed. The study focuses on the determination of the liquid–liquid phase behavior in a temperature range of (267–423) K at atmospheric pressure. UCSTs were observed in between 280 K and 415 K. The results are complementing prior measurements on similar IL-CnOH systems concerning ILs with longer side chain. A numerical analysis of the phase diagrams on the basis of Ising criticality was applied presuming the validity of the rectilinear diameter or a nonlinear diameter as requested by the theory of complete scaling. The results (UCST, cr...

The Effect of the Molecular Size and Shape on the Volume Behavior of Binary Liquid Mixtures. Branched and Cyclic Alkanes in Heptane at 298.15 K

Excess molar volumes VE for 40 mixtures of heptane with a liquid alkane and apparent molar volumes in heptane for eight solid alkanes have been obtained at 298.15 K. They include five linear, 30 branched-chain, and 13 cyclic alkanes. Almost all systems exhibit negative VE values. For mixtures with open chain alkanes, VE increases from C5 to C7 and then decreases. A similar trend is shown by mixtures with cycloalkanes. VE values are compared with known HE data for mixtures with heptane and tetrachloromethane. Signs and trends of VE and HE are correlated with the free volume and interactional terms of the Flory theory. The partial molar volumes at infinite dilution in heptane, V°, have also been obtained and discussed together with literature data on other hydrocarbons and polar compounds. The calculated contributions to V° by CH3, CH2, CH and C groups are compared with previously determined contributions of polar groups. The lower contributions of the latter groups are explained with the volume contraction caused by dipole-induced dipole interaction. The volume effects associated with branching and cyclization have been evaluated and compared with the corresponding effects on solvation enthalpy. The branching effect, in the order of magnitude of few cm3·mol−1, and the larger negative values of cyclization volumes, down to −24 cm3·mol−1, are discussed in terms of packing and solute–solvent interactions, in analogy to polar organic solutes either in heptane and tetrachloromethane. A negative cyclization effect is also exhibited by the solvation enthalpies.

Local theory for ions in binary liquid mixtures

The influence of ions on the bulk phase behavior of binary liquid mixtures acting as their solvents and on the corresponding interfacial structures close to a planar wall is investigated by means of density functional theory based on local descriptions of the effective interactions between ions and their solvents. The bilinear coupling approximation (BCA), which has been used in numerous previous related investigations, is compared with a novel local density approximation (LDA) for the ion-solvent interactions. It turns out that within BCA the bulk phase diagrams, the two-point correlation functions, and critical adsorption exhibit qualitative features which are not compatible with the available experimental data. These discrepancies do not occur within the proposed LDA. Further experimental investigations are suggested which assess the reliability of the proposed LDA. This approach allows one to obtain a consistent and rather general understanding of the effects of ions on solvent properties. From our analysis we infer, in particular, that there can be an experimentally detectable influence of ions on binary liquid mixtures due to steric effects but not due to charge effects.

Prediction of associational behaviour of binary liquid mixtures from viscosity data at 298.15, 303.15, 308.15 and 313.15 K

Densities and viscosities were measured for the binary liquid mixtures formed by benzonitrile, chlorobenzene, benzyl chloride and benzyl alcohol with benzene at T = 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure over the whole concentration range. Prigogine–Flory–Patterson (PFP) and Ramaswami and Anbananthan models were used to study the associational behaviour of two weakly interacting liquids. The models were also tested for different systems showing that the latter yields fair agreement between theory and experiment. The experimental values of viscosities were fitted to the Redlich–Kister polynomial relation to estimate the binary coefficients and standard errors. Furthermore, McAllister multibody interaction model is used to correlate the binary viscosities with the experimental findings.

Non-ideal behaviour of binary liquid mixtures and different approaches to calculate ideal expansibility

Densities for binary mixtures of cyclopentane with 1-propanol, 1-pentanol, and 1-heptanol over the whole composition range have been measured at temperature 318.15 K. From these densities, excess molar volumes were calculated. All the experimental excess molar volumes were fitted to Redlich–Kister equation and were analyzed with the help of Prigogine–Flory–Patterson theory. Also isobaric expansibilities and their excess counterparts were calculated. Further different approaches were analysed for calculating ideal expansibilities.

Temperature-Driven Mixing-Demixing Behavior of Binary Mixtures of the Ionic Liquid Choline Bis(trifluoromethylsulfonyl)imide and Water

The ionic liquid (2-hydroxyethylammonium)trimethylammonium) bis(trifluoromethylsulfonyl)imide (choline bistriflimide) was obtained as a supercooled liquid at room temperature (melting point=30 degrees C). Crystals of choline bistriflimide suitable for structure determination were grown from the melt in situ on the X-ray diffractometer. The choline cation adopts a folded conformation, whereas the bistriflimide anion exhibits a transoid conformation. The choline cation and the bistriflimide anion are held together by hydrogen bonds between the hydroxyl proton and a sulfonyl oxygen atom. This hydrogen bonding is of importance for the temperature-dependent solubility properties of the ionic liquid. Choline bistriflimide is not miscible with water at room temperature, but forms one phase with water at temperatures above 72 degrees C (equals upper critical solution temperature). 1H NMR studies show that the hydrogen bonds between the choline cation and the bistriflimide anion are substantially weakened above this temperature. The thermophysical properties of water-choline bistriflimide binary mixtures were furthermore studied by a photopyroelectric technique and by adiabatic scanning calorimetry (ASC). By photothermal analysis, besides highly accurate values for the thermal conductivity and effusivity of choline bistriflimide at 30 degrees C, the detailed temperature dependence of both the thermal conductivity and effusivity of the upper and lower part of a critical water-choline bistriflimide mixture in the neighborhood of the mixing-demixing phase transition could be determined with high resolution and accuracy. Together with high resolution ASC data for the heat capacity, experimental values were obtained for the critical exponents alpha and beta, and for the critical amplitude ratio G+/G-. These three values were found to be consistent with theoretical expectations for a three dimensional Ising-type of critical behavior of binary liquid mixtures.

Molecular interaction studies of the volumetric behavior of binary liquid mixtures containing alcohols

An attempt has been made to relate the volumetric effects involved in the binary mixtures of normal and branched alcohols and various components (aromatics, halo and nitroaromatics and haloaliphatics) with the molecular interactions of unlike molecules. This review is a condensation of research activities developed in recent years as results of a better understanding of volumetric behavior and a stronger insight into the complex structure of those mixtures. The influence of important contributions of a physical, chemical and geometrical nature that change excess molar volume, VE (positive, sigmoidal, negative) is considered and explained in detail. It appears that the balance between these contributions is quite sensitive to the behavior of the alcohol molecules in contact with the chosen compounds.

Thermodynamic and Transport Behavior of Binary Liquid Mixtures of 1-Decanol with Hexadecane and Squalane at 298.15, 303.15 and 308.15 K

Abstract This paper presents densities, ρ, speeds of sound, u and viscosities, η of pure 1decanol, C10H21OH, hexadecane, C16H34, squalane (2,4,6,10,15,19,23-hexamethyltetraco- sane), C30H62 and their binary liquid mixtures, with 1-decanol, C10H21OH as a common component, over the whole composition range at 298.15, 303.15 and 308.15 K. The excess molar volume, V m E , excess molar isentropic compressibility, K E S , m , deviation of the speed of sound, u D , from their ideal values u id in an ideal mixture, and viscosity deviation, Δη were calculated from experimental data. The apparent molar volumes, Φ v , i and apparent molar isentropic compressibilities, Φ k , i were also calculated. The values of Φ v , i and Φ k , i were used to estimate the partial molar volumes and partial molar isentropic compressibilities at infinite dilution, ߙV¯ Φ,i 0 and ߙK¯ Φ,i 0, respectively. Apart from using density data for calculating V m E , excess molar volumes have also been estimated by using Prigogine-Flory-Patterson (PFP) theory.

Surface thermodynamic behaviour of binary liquid mixtures of benzene+1,1,2,2-tetrachloroethane at different temperatures: an experimental and theoretical study

Surface tensions, σ, of pure benzene, 1,1,2,2-tetrachloroethane and those of their binary liquid mixtures over the whole composition range at 298.15, 308.15 and 313.15 K have been measured. The experimental σ data have been correlated against temperature and concentration using standard relations. The measured values have been used to calculate various useful thermodynamic parameters, viz., deviation in surface tension, Δσ, surface entropy, S s, and surface enthalpy, H s. The sign and magnitude of these parameters were discussed in terms of molecular interactions between the component molecules of the liquid mixtures. A number of empirical, semi-empirical and statistical models and theories such as Aurebach, Sanchez, Goldsach–Sarvas volume fraction statistics, Brock and Bird relation, Sudgen's relation and Flory–Patterson–Rastogi model have been used to compute theoretically the values of surface tension. Moreover, deviation in surface tension, Δσ has also been calculated using HSIS and HSEG theories and found to be qualitatively correct.

Thermodynamic and transport behaviour of binary liquid mixtures of benzyl alcohol with monocyclic aromatics at 303.15 K

This paper presents densities, ρ, ultrasonic speeds, u, viscosities, η, and refractive indices, n, of pure benzyl alcohol (BA), benzene (B), chlorobenzene (CB), benzonitrile (BN), nitrobenzene (NB), and their binary liquid mixtures, with BA as a common component, over the whole composition range at 303.15 K. The excess molar volumes, V E, deviations in isentropic compressibility, Δ k s, viscosity, Δ η, ultrasonic speed, Δ u, and in refractive index, Δ n, were calculated from the experimental data. The apparent molar volumes, V ϕ,2, and apparent molar isentropic compressibilities, K ϕ,2, of B, CB, BN and NB in BA were also calculated. The values of V ϕ,2 and K ϕ,2 were used to estimate the partial molar volumes, V¯ ϕ,2 0, and partial molar isentropic compressibilities, K¯ ϕ,2 0, of B, CB, BN and NB in BA at infinite dilution. The variations of these parameters with composition of the mixtures suggest that the interaction between BA and B/CB/BN/NB molecules follow the sequence: B < CB < BN < NB. Apart from using density data for the calculation of V E, excess molar volumes have also been estimated by using Flory's statistical theory. The results show that Flory's theory predicts V E well for the mixture with least interaction between the component molecules while it shows large deviation for the mixture showing highest interaction.

Volumetric behaviour of binary liquid mixtures of dimethylsulphoxide with substituted benzenes at 303.15 k

Excess molar volumes (V E ) for binary mixtures of dimethyl sulphoxide (DMSO) with substituted benzenes have been measured at 303.15 K. The substituted benzenes include toluene, ethylbenzene, chlorobenzene, bromobenzene and nitrobenzene. The measured V E data is positive for the mixtures of DMSO with nitrobenzene and is completely negative over the entire composition range in the mixtures of toluene, ethylbenzene and chlorobenzene and an inversion in sign is observed in the bromobenzene system. The experimental results are analysed in terms of intermolecular interactions and effect of substitutents on benzene ring between unlike molecules.

Binary liquid mixtures in porous solids.

The technique of nuclear magnetic resonance cryoporometry has been used to study the behavior of binary liquid mixtures of water and decane in porous sol-gel silicas. It was observed that the water preferentially adsorbed onto the silica surface and so was able to displace the decane from the pores.

Volumetric behaviour of binary liquid mixtures of 2-methoxyethanol with n-butylamine, sec-butylamine and tert-butylamine

Densities of binary mixtures containing 2-methoxyethanol with n -butylamine, sec -butylamine and tert -butylamine have been determined at different temperatures, between 291.15 and 313.15 K, over the complete concentration range. Excess molar volumes were calculated and the departure from ideal behaviour is explained on the basis of specific interactions between the components in these mixtures.

Volumetric behaviour of binary liquid mixtures of 2-methoxyethanol with n-butylamine, sec-butylamine and tert-butylamine

Densities of binary mixtures containing 2-methoxyethanol with n-butylamine, sec-butylamine and tert-butylamine have been determined at different temperatures, between 291.15 and 313.15 K, over the complete concentration range. Excess molar volumes were calculated and the departure from ideal behaviour is explained on the basis of specific interactions between the components in these mixtures.