Binary Mixture System Research Articles

Phase behaviour for the (CO2 + 1-butyl-2-pyrrolidone) and (CO2 + 1-octyl-2-pyrrolidone) systems at temperatures from (313.2 to 393.2) K and pressures up to 28 MPa

Phase equilibrium for two binary systems, (CO2 + 1-butyl-2-pyrrolidone) and (CO2 + 1-octyl-2-pyrrolidone) mixture, were measured at five experimental temperatures of (313.2, 333.2, 353.2, 373.2 and 393.2) K and pressure from (4.45 to 28.72) MPa. The (vapour + liquid) equilibria for the 1-butyl-2-pyrrolidone and 1-octyl-2-pyrrolidone play a significant role as organic solvents in numerous industrial processes. Both (CO2 + 1-butyl-2-pyrrolidone) and (CO2 + 1-octyl-2-pyrrolidone) binary mixture systems have critical mixture curves that represent maximums in pressure-temperature diagram between the critical temperatures of CO2 and 1-butyl-2-pyrrolidone or CO2 and 1-octyl-2-pyrrolidone. The (CO2 + 1-butyl-2-pyrrolidone) and (CO2 + 1-octyl-2-pyrrolidone) systems display type-I phase behaviour. The experimental results for the (CO2 + 1-butyl-2-pyrrolidone) and (CO2 + 1-octyl-2-pyrrolidone) binary systems are correlated with Peng-Robinson equation of state including two (kij, ηij) adjustable parameters.

Thermal-Concentration Convection in a System Of Viscous Liquid and Binary Mixture in a Plane Channel with Small Marangoni Numbers

A conjugated initial-boundary-value problem occurring in the movement of a binary mixture and viscous heat-conductive liquid with a common interface surface under the action of thermal-concentration forces is under consideration. A solution describing a stationary flow in layers, temperature distribution, and concentration distribution is determined. The Laplace transform method is used to obtain a nonstationary solution for the problem in images, which makes it possible to describe the evolution of the movement using the numerical inversion of images.

Sensor array for qualitative and quantitative analysis of metal ions and metal oxyanion based on colorimetric and chemometric methods

Gold nanoparticle (AuNP)-based colorimetric sensor is sensitive for the detection of metal ions and metal oxyanion in aqueous solution. However, this method is usually not suitable for multi-objective analysis in complex mixture systems because it is suffering from interference of co-existents. In the present paper, we proposed a sensitive, flexible, low-cost, and multi-units sensor method for the qualitative and quantitative analysis of metal ions and metal oxyanion based on the global ultraviolet and visible (UV–Vis) spectra of amino acid-gold nanoparticles (amino acid-AuNPs) sensors in the range of 230–800 nm. Different amino acids (L-Histidine, L-Lysine, L-Methionine, D-Penicillium) which can prevent the aggregation of the AuNPs in NaCl solution, were investigated to build sensor arrays responding to different ions induced AuNPs aggregation. The UV–Vis spectra that Cd2+, Ba2+, Mn2+, Ni2+, Cu2+, Fe3+, Cr3+, Cr2O72-, Sn4+, Pb2+ induce amino acid-AuNPs displayed different characteristics and the ions were classified correctly by using partial least squares-discriminant analysis (PLS-DA). Taking the advantage of the multivariate analysis and sensor arrays, we simultaneously quantified the ions in binary and ternary mixture systems (Cr3+/Cr2O72-, Fe3+/Cd2+, Fe3+/Cr3+/Cr2O72-). Data fusion methods further improved the prediction accuracy of the chemometric models built on multi-amino acids-AuNPs sensors. The proposed method has a potential for analyzing metal ions and metal oxyanion in much more complex mixture systems.

Assessment of a bubble-based bi-disperse drag model for the simulation of a bubbling fluidized bed with a binary mixture

In the simulation of a bubbling fluidized bed, it is necessary to consider the bubble effect on interphase drag force. In this work, the bubble-based drag model is extended to a binary mixture system. A bi-disperse gas-solid drag model considering the bubble effect is developed and implemented into the multi-fluid model. Three simulations of a bubbling fluidized bed with a binary mixture are carried out. The mixing and segregation performance of binary mixture is investigated. Meanwhile, the sensitivity analysis of drag model to local structure parameters is conducted. The results reveal that the bi-disperse drag model does not only depend on the voidage, but also on the solid component. With consideration of bubble effects, the predicted bed expansion is reduced and the model can obtain a better agreement with experimental results.

Study of the H-bond interaction on binary mixtures of nitromethane with primary alcohols at different temperatures using dielectric parameters

A dielectric spectroscopic study has been carried out on binary mixtures of polar nitromethane (NM) with primary alcohols: ethanol (ETH), 1-propanol (1-PRO) and 1-butanol (1-BUT) at different temperatures. The complex dielectric spectra of pure and binary mixtures were described by Debye model. The dielectric constant (e0), relaxation time (τ), and dielectric constant at an optical frequency (e∞) of binary mixtures were determined at various temperatures. The computed excess dielectric parameters were used to interpret the intermolecular interaction between the unlike dipoles within the binary mixture system. From the experimental analysis, it is confirmed that, the mixture molecules form H-bond complex structure and dipoles are aligned in anti-parallel direction. Among all the binary systems, strong H-bond interaction can be seen in NM + 1-PRO mixture system. Rapid decrement of relaxation time for NM + 1-BUT binary system results higher amount of structural changes symmetry breaking effect. The formation of hydrogen bonding interaction between oxygen atom of nitro groups in NM and hydrogen atom of alcohols in binary mixture systems was confirmed by FTIR analysis.

1-Ethyl-2,3-dimethylimidazolium tetrafluoroborate ionic liquid mixture as electrolyte for high-voltage supercapacitors

A novel ionic liquid (IL) 1-ethyl-2,3-dimethylimidazolium tetrafluoroborate ([Emmim][BF4]) with trialkyl substitution imidazolium cation was synthesized, and its binary system blended with acetonitrile (ACN) under different concentrations were prepared and investigated as possible electrolytes for supercapacitors. The physico-chemical properties such as density, viscosity, and electrical conductivity of the binary mixture system were measured from 288.15 to 333.15 K. The temperature dependences of density, viscosity, and electrical conductivity were illustrated and discussed by the Vogel-Fulcher-Tamman (VFT) equation and Arrhenius equation. It was found that the VFT equation was more suitable to [Emmim][BF4] + ACN system. Further, the important characteristics of this IL-based electrolyte for supercapacitors including the maximum operative voltage, the capacitance, the energy density, and power density were measured and calculated by cyclic voltammetry (CV), electrochemical impedance spectrum (EIS), and galvanostatic charge-discharge. The results show that the performance of the electrolyte can be improved with appropriate ratio of IL. When the concentration of the IL increased to 0.8 mol L−1, the maximum operative voltage increased to 5.9 V, and the specific capacitance achieves 142.6 F g−1. It shows the IL-based mixtures with excellent characteristics are applicable as high-voltage electrolytes for supercapacitors.

Density, Electrical Conductivity, Dynamic Viscosity, Excess Properties, and Molecular Interactions of Ionic Liquid 1-Cyanopropyl-3-methylimidazolium Tetrafluoroborate and Binary System with Acetonitrile

In this work, a novel binary mixture system containing the ionic liquid (IL) 1-cyanopropyl-3-methylimidazolium tetrafluoroborate ([PCNmim][BF4]) and acetonitrile (AN) was prepared. The density, dynamic viscosity, and electrical conductivity of the pure IL and the binary system at different ratios were determined at atmospheric pressure from 288.15 to 323.15 K. We have estimated a series of important thermodynamic parameters of the pure IL by empirical equations and correlated the temperature dependences of the electrical conductivity and dynamic viscosity of the binary system using both the Vogel–Fulcher–Tamman and Arrhenius equations. We also focused on the excess molar volume, VE, of the binary mixture system, and the results of the VE were correlated to the Redlich–Kister polynomial equation. Then, the interstice model and excess volume were employed to investigate the structural properties and packing structure, respectively, of the pure [PCNmim][BF4] and IL + AN mixtures. For a deep understanding of ...

Synergistic Adsorption of Polyaromatic Compounds on Silica Surfaces Studied by Molecular Dynamics Simulation

Adsorption on silica surfaces of polyaromatic compounds, N-(1-hexylhepyl)-N′-(5-carboxylicpentyl)-perylene-3,4,9,10-tetracarboxylic bisimide (C5Pe) and N-(1-undecyldodecyl)-N′-(5-carboxylicpentyl)-perylene-3,4,9,10-tetracarboxylic bisimide (C5PeC11), individually and their binary mixture in heptol (mixture of heptane and toluene as oil) solutions were studied by molecular dynamics (MD) simulation, quartz crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM). The MD simulation results showed that C5Pe molecules tend to aggregate and form a large cluster rapidly in the oil phase, reducing the energy of the system. In contrast, C5PeC11 molecules with higher solubility tend to disperse in the system. As a result, C5PeC11 molecules exhibited a stronger adsorption than C5Pe molecules on silica surfaces. In the binary mixture system, the overall solubility is only slightly lower than that in the C5PeC11 system due to the association of C5Pe with C5PeC11 molecules through π–π stacking a...

Binding branched and linear DNA structures: From isolated clusters to fully bonded gels.

The proper design of DNA sequences allows for the formation of well-defined supramolecular units with controlled interactions via a consecution of self-assembling processes. Here, we benefit from the controlled DNA self-assembly to experimentally realize particles with well-defined valence, namely, tetravalent nanostars (A) and bivalent chains (B). We specifically focus on the case in which A particles can only bind to B particles, via appropriately designed sticky-end sequences. Hence AA and BB bonds are not allowed. Such a binary mixture system reproduces with DNA-based particles the physics of poly-functional condensation, with an exquisite control over the bonding process, tuned by the ratio, r, between B and A units and by the temperature, T. We report dynamic light scattering experiments in a window of Ts ranging from 10 °C to 55 °C and an interval of r around the percolation transition to quantify the decay of the density correlation for the different cases. At low T, when all possible bonds are formed, the system behaves as a fully bonded network, as a percolating gel, and as a cluster fluid depending on the selected r.

Thermal-Concentration Convection in a System of Viscous Liquid and Binary Mixture in a Plane Channel with Small Marangoni Numbers

Thermal-Concentration Convection in a System of Viscous Liquid and Binary Mixture in a Plane Channel with Small Marangoni Numbers

Crystallization Behavior of Molecular Compound in Binary Mixture System of 1,3‐Dioleoyl‐2‐Palmitoyl‐sn‐Glycerol and 1,3‐Dipalmitoyl‐2‐Oleoyl‐sn‐Glycerol

AbstractPrevious studies showed that the stable β‐form of molecular compound (MC) crystals having a double‐chain‐length structure is formed in a binary mixture system of 1,3‐dioleoyl‐2‐palmitoyl‐sn‐glycerol (OPO) and 1,3‐dipalmitoyl‐2‐oleoyl‐sn‐glycerol (POP) with a 1:1 concentration ratio of OPO and POP. The use of MC crystals made of POP and OPO for edible applications, such as margarine, is advantageous due to no‐trans, low‐saturated, and high‐oleic fats. Industrial manufacturing technology involves rapid cooling processes, and the kinetic properties of crystallization of MC of OPO and POP are required. In this study, we clarified the crystallization of MC of OPO and POP under rapid cooling at rates of 1–150 °C min−1, using synchrotron radiation time‐resolved X‐ray diffraction and differential scanning calorimetry methods. The main results are as follows: (1) POP and OPO crystallized in separate manners without the formation of MC crystals under rapid cooling (>40 °C min−1), while MC crystals started to form with decreasing rates of cooling in addition to the POP and OPO crystals (<30 °C min−1); (2) metastable and stable forms sub‐α, α, β′, and β of POP and OPO were formed, whereas the MC crystals of β were formed during the cooling processes; and (3) the heating processes after crystallization by rapid cooling caused separate melting of the metastable and stable forms of POP and OPO crystals and the formation of MC crystals of β made of POP and OPO, as well as melting of the MC crystals alone.

Understanding the behavior of binary system contains N, N-dimethylformamide and N-methylanlinine in terms of thermo-acoustic parameters at different temperatures

Thermodynamic elementary parameters such asdensity (ρ), viscosity (η), and speed of sound(U) values of the binary mixture system containsN,N-Dimethylformamide (DMF) with N-Methylaniline (NMA)and for pure liquids were calibrated over the whole combinations at different temperatures (303.15, 308.15 and 313.15) K. From these experimentaldata, various excess thermo-acoustic parameters such as excess isentropic compressibility (KsE), excess molar volume (VE) and excess free length (LfE), excess Gibb’s free energy (ΔG*E), and excess enthalpy (HE) have been calculated. The variations of these properties with composition for these binary mixtures suggest loss of dipolar association, difference in size and shape of the component molecules, dipole-dipole interactions and hydrogen bonding between unlike molecules. The excess parameters have been fitted to the Redlich-Kister polynomial equation using multi-parametric linear regression analysis to derive the binary coefficients and to estimate the standard deviation. Experimental ultrasonic velocities were correlated with various theories such as Nomoto’s relation (UNOM), Junjie’s method (UJM), Impedance relation(UIMP) and Free length theory (UFLT) at all temperatures.

Fragment Molecular Orbital Based Parametrization Procedure for Mesoscopic Structure Prediction of Polymeric Materials.

In the analyses of miscibility behaviors of macromolecules and polymers, dissipative particle dynamics (DPD) simulations are generally performed. In these simulations, the so-called χ parameters describing the effective interactions among particles are crucial. It has been known that such parameters can be obtained within the classical or empirical force field frameworks. However, there is a potential problem that charge transfer and polarization occasionally occur. Additionally, satisfactory reference parameters are not available for some cases. Therefore, we developed a new procedure to evaluate the set of parameters by using the ab initio fragment molecular orbital (FMO) method which can provide the set of interaction energies among segments as polymer units. Moreover, we evaluated the anisotropy of molecules by using the FMO-based effective interaction parameters for three standard binary mixture systems (hexane-nitrobenzene, polyisobutylene-diisobutyl ketone, and polyisoprene-polystyrene). The calculated values showed good agreement with the experimental values with about 10% errors.

Usefulness of multi-solids pneumatic transport bed data for evaluation and validation of binary solids computational simulation models

The hydrodynamics of the binary mixture system in the multisolid pneumatic transport bed (MPTB), where a fine-particle laden gas flows through a coarse particle bed, was investigated by computational fluid dynamics (CFD) simulation. A pseudo-homogeneous method, which considers the gas phase and the fine particle phase as one pseudo-homogeneous dilute phase, was proposed to predict the coarse particle terminal velocity. In the second approach, the fine particle and coarse particle are treated separately, with the structure-based drag model developed in our previous study being used to simulate the coarse particle terminal velocity and fine particle holdup in the coarse particle bed. The simulation results of the two methods showed reasonable agreement with the experimental data under different operating conditions. As observed in the experiment, the terminal velocity of coarse particles decreases with increasing the fine particle flow rate, and the reduction is more significant for larger coarse particles. Besides, the fine particle holdup increases with the decrease of the diameter of coarse particles. These results demonstrated that the multisolid pneumatic transport system can serve as a simple binary system, with its coarse particle terminal velocity and fine particle holdup being used for the verification and validation of binary-particle CFB models.

Joint toxicity of six common heavy metals to Chlorella pyrenoidosa.

Six common heavy metals (Ni, Fe, Zn, Pb, Cd, and Cr) in the water environment were selected to present five groups of binary mixture systems (Ni-Fe, Ni-Zn, Ni-Pb, Ni-Cd, and Ni-Cr) through a direct equipartition ray design. Microplate toxicity analysis based on Chlorella pyrenoidosa measured the 96-h joint toxicities of the binary mixtures. Toxicity interaction of the binary mixture was analyzed by comparing the observed toxicity data with the reference model (concentration addition). The results indicated that Ni-Fe, Ni-Pb, and Ni-Cr mixtures showed additive effects at concentration tested. It was indicated that Ni-Zn and Ni-Cd mixtures presented additive effects at low concentrations whereas synergistic effects were seen at high concentrations.

Effect of the Hartmann number on phase separation controlled by magnetic field for binary mixture system with large component ratio

This paper presents an exploration for phase separation in a magnetic field using a coupled lattice Boltzmann method (LBM) with magnetohydrodynamics (MHD). The left vertical wall was kept at a constant magnetic field. Simulations were conducted by the strong magnetic field to enhance phase separation and increase the size of separated phases. The focus was on the effect of magnetic intensity by defining the Hartmann number (Ha) on the phase separation properties. The numerical investigation was carried out for different governing parameters, namely Ha and the component ratio of the mixed liquid. The effective morphological evolutions of phase separation in different magnetic fields were demonstrated. The patterns showed that the slant elliptical phases were created by increasing Ha, due to the formation and increase of magnetic torque and force. The dataset was rearranged for growth kinetics of magnetic phase separation in a plot by spherically averaged structure factor and the ratio of separated phases and total system. The results indicate that the increase in Ha can increase the average size of separated phases and accelerate the spinodal decomposition and domain growth stages. Specially for the larger component ratio of mixed phases, the separation degree was also significantly improved by increasing magnetic intensity. These numerical results provide guidance for setting the optimum condition for the phase separation induced by magnetic field.

Multistep Heterogeneous Nucleation in Binary Mixtures of Charged Colloidal Spheres.

Nucleation plays a decisive role in determining the crystal structure and size distribution; however, understanding of the fundamentals of nucleation is quite limited. In particular, it is unclear whether a nucleus forms spontaneously from solution via a single- or multiple-step process. Here we show how a binary mixture of charged colloidal spheres nucleates heterogeneously on a flat substrate by means of Bragg microscopy, laser diffraction, and laser microscopy. In contrast with the conventional one-step and two-step nucleation mechanisms, a novel pathway of multistep heterogeneous nucleation under certain experimental conditions is highlighted by four steps: initial homogeneous fluid → prenucleation clusters → preordered prenucleation clusters → intermediate ordered phase → final crystal. It is expected that the obtained results would be helpful in rationalizing the rich phase behavior exhibited by the binary mixture systems and in developing better and broadly applicable nucleation models as well as in designing defect-free single-crystal alloys.

Organosilica Membrane with Ionic Liquid Properties for Separation of Toluene/H₂ Mixture.

In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H2/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H2 (>17,000) in a binary mixture system based on a solution–diffusion mechanism with improved durability over the supported ionic liquid membrane.

New entry for fluorinated carbocycles: Unprecedented 3,6-disubstituted 1,1,2,2-tetrafluorocyclohexane derivatives

The synthetic protocols for symmetrical/unsymmetrical 3,6-disubstituted 1,1,2,2-tetrafluorocyclohexane molecules were successfully established for the first time. Some of thus obtained tetrafluorinated cyclohexanes underwent recrystallization to afford trans-configured products preferentially. One of the unsymmetrical trans-disubstituted tetrafluorocyclohexanes, trans-1-ethyl-2,2,3,3-tetrafluoro-4-[4-(trans-4-n-propylcyclohex-1-yl)phenyl]cyclohexane, was found to possess a low birefringence Δn (0.073) and a large negative dielectric anisotropy Δε (–9.4) in a binary mixture system, which were very prominent as characteristics of LC molecules in VA-mode driving LC displays.

An Investigation of the Restitution Coefficient Impact on Simulating Sand-Char Mixing in a Bubbling Fluidized Bed

In the present work, the effect of the restitution coefficient on the numerical results for a binary mixture system of sand particles and char particles in a bubbling fluidized bed with a huge difference between the particles in terms of density and volume fraction has been studied based on two-fluid model along with the kinetic theory of granular flow. Results show that the effect of restitution coefficient on the flow characteristics varies in different regions of the bed, which is more evident for the top region of the bed. The restitution coefficient can be categorized into two classes. The restitution coefficients of 0.7 and 0.8 can be included into one class, whereas the restitution coefficient of 0.9 and 0.95 can be included into another class. Moreover, four vortices can be found in the time-averaged flow pattern distribution, which is very different from the result obtained for the binary system with the similar values between particles in density and volume fraction.