Physical Properties Of Binary Mixtures Research Articles

Mixing twist-bend and ferroelectric nematic liquid crystals.

Twist-bend (N_{tb}) and ferroelectric (N_{F}) nematic liquid crystals exhibit several novel effects and new physical properties. Here, we report experimental studies on the phase diagram and some physical properties of binary mixtures of CB9CB and RM734 mesogens. Both N-N_{tb} and N-N_{F} phase transition temperatures and the corresponding enthalpies decrease significantly and, eventually, these transitions disappear at some intermediate compositions, stabilizing wide nematic phase (N). Temperature-dependent birefringence several degrees above the N-N_{tb} phase transition shows strong director tilt fluctuations. The critical range of the fluctuations increases with the nematic range and the critical exponent is consistent with the mean field. The spontaneous polarization of RM734 decreases drastically with the addition of CB9CB mesogen. The temperature dependence of the splay elastic constant of the mixtures' high-temperature nematic (N) phase strikingly differs from that of the pristine CB9CB and RM734 mesogens. The study shows that a small inclusion of either compound has a substantial effect on the phase diagram and physical properties.

Physical Properties of Binary Mixtures of n-Dodecane and Various Ten-Carbon Aromatic Compounds (2-Methyl-1-phenylpropane, 2-Methyl-2-phenylpropane, 2-Phenylbutane, and 1,3-Diethylbenzene): Densities, Viscosities, Speeds of Sound, Bulk Moduli, Surface Tensions, and Flash Points at T = (293.15–333.15) K and 0.1 MPa

Mixtures of n-dodecane with C10H14 aromatic isomers (iso-butylbenzene, sec-butylbenzene, tert-butylbenzene, and 1,3-diethylbenzene) were analyzed for density, viscosity, speed of sound, surface ten...

Determination of the Rate-Limiting Step in Fatty Acid Transport.

The generally accepted model of free fatty acid (FA) transport through cellular membranes occurs in three steps, adsorption of the FA onto the membrane, translocation across the membrane ("flip-flop"), and subsequent desorption of the FA into the cytosol. There still exists some dispute as to the identity of the rate-limiting step of FA transport. In the present study, sum-frequency vibrational spectroscopy (SFVS) was used to directly measure the rate of stearic acid (SA) flip-flop in planar supported lipid bilayers (PSLBs) comprised of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC). The impact of SA on the physical properties of binary mixtures of SA and DSPC was investigated via Π-A isotherms from which the excess free energies of mixing and compression moduli were calculated. The manner in which these physical changes influenced the rates of SA and DSPC flip-flop was subsequently examined using SFVS. The rates of SA and DSPC flip-flop revealed that SA flip-flops independently of DSPC and on much faster time scales than its phospholipid counterpart. SFVS was also used to probe the rate of protein-unassisted SA desorption from hybrid supported lipid bilayers (HSLBs), allowing for the first decoupled measurement of the rates of desorption and flip-flop. These results provide strong evidence for desorption being the rate-limiting step in FA transport through the membrane in the absence of proteins.

Influence of temperature on thermo physical properties of binary mixtures of ethyl acrylate and alkyl amines: An experimental and theoretical approach

Densities (ρ) and speed of sound (u) values have been measured for the binary mixtures of ethyl acrylate with propylamine, dipropylamine, diisopropylamine and tripropylamine at four temperatures (T = 303.15, 308.15, 313.15 and 318.15 K) and at atmospheric pressure over the entire composition range. Further, the measured data has been utilized to compute excess molar volume (VmE) and excess isentropic compressibility (κSE) for all the systems under the same experimental conditions. Expansion of our study has been done by calculating other thermodynamic parameters such as excess intermolecular free length (LfE) and excess speed of sound (uE). These calculated excess parameters have been correlated by Redlich-Kister equation. The experimental results have also been analysed by using Prigogine–Flory–Patterson (PFP) theory, intermolecular free length theory and collision frequency theory. To elucidate the presence of intermolecular interactions and structural effects the work has been augmented by FTIR studies also.

Comparative study of physical properties of binary mixtures of halogen free ionic liquids with alcohols

Densities, refractive indices and speeds of sound along with their excess or deviation properties for both 1,3-dimethylimidazolium methylsulfate ([dmim][MeSO4]) and 1-ethyl-3-methylimidazolium methylsulfate ([emim][MeSO4]) with 1-propanol, 1-butanol and 1-pentanol over the entire range of mole fraction are reported at temperatures ranging from 298.15K to 313.15K and atmospheric pressure. Isentropic and excess isentropic compressibilities for both ionic liquids with 1-alcohols were calculated from the experimental results. Excess and deviation properties were further correlated using the Redlich-Kister polynomial. The measured speeds of sound were compared to the values obtained from Schaaffs' collision factor theory, Jacobson's intermolecular free length theory of solutions and Nomoto’s relation. In addition, the experimentally obtained refractive indices were compared to the calculated values using Lorentz-Lorenz, Dale-Gladstone and Eykman mixing rules.

Density and Viscosity from 293.15 to 373.15 K, Speed of Sound and Bulk Modulus from 293.15 to 343.15 K, Surface Tension, and Flash Point of Binary Mixtures of Bicyclohexyl and 1,2,3,4-Tetrahydronaphthalene or Trans-decahydronaphthalene at 0.1 MPa

In this work, the physical properties of binary mixtures of bicyclohexyl and 1,2,3,4-tetrahydronaphthalene (tetralin) or trans-decahydronaphthalene (trans-decalin) were measured. Densities and viscosities were measured at temperatures from 293.15 to 373.15 K, and speeds of sound were measured at temperatures from 293.15 to 343.15 K. At 303.15 K, pure component values of density (960.9, 878.93, 862.29 kg·m–3), viscosity (1.85, 3.18, 1.79 mPa·s), and speed of sound (1450.2, 1422.7, 1357.5 m·s–1) are consistent with literature values for tetralin, bicyclohexyl, and trans-decalin, respectively. Density mole fraction data were fit to second- or third-order polynomials. Viscosity mole fraction data were fit using the three-body McAllister model. The bulk modulus ranged from 1206 to 2149 MPa over 293.15 to 343.15 K. For tetralin mixtures, increasing tetralin increased density, speed of sound, bulk modulus, and surface tension and decreased viscosity and flash point. For trans-decalin mixtures, increasing trans-d...

Density, Viscosity, Speed of Sound, Bulk Modulus, Surface Tension, and Flash Point of Binary Mixtures of 2,2,4,6,6-Pentamethylheptane and 2,2,4,4,6,8,8-Heptamethylnonane at (293.15 to 373.15) K and 0.1 MPa and Comparisons with Alcohol-to-Jet Fuel

In this work, the physical properties of binary mixtures of 2,2,4,6,6-pentamethylheptane and 2,2,4,4,6,8,8-heptamethylnonane were measured and compared with those of alcohol-to-jet fuel. Density and viscosity were measured at temperatures ranging from (293.15 to 373.15) K, and speed of sound was measured at temperatures ranging from (293.15 to 343.15) K. At 293.15 K, pure component values for 2,2,4,4,6,8,8-heptamethylnonane of 784.48 kg·m–3, 3.71 mPa·s, and 1285.8 m·s–1 for density, viscosity, and speed of sound, respectively, agree with literature values. Similarly for 2,2,4,6,6-pentamethylheptane, the values of 745.21 kg·m–3, 1.31 mPa·s, and 1203.7 m·s–1 for density, viscosity, and speed of sound, respectively agree with literature values. Density and mole fraction data were fit to a second-order polynomial at each temperature. Values for bulk modulus ranged from (732 to 1297) MPa over (293.15 to 343.15) K. Viscosity mole fraction data were fit using the three-body McAllister model, whereas the viscosit...

Density, Viscosity, Speed of Sound, Bulk Modulus, and Surface Tension of Binary Mixtures of n-Heptane + 2,2,4-Trimethylpentane at (293.15 to 338.15) K and 0.1 MPa

In this work, the physical properties of binary mixtures of n-heptane and 2,2,4-trimethylpentane were measured. Density and speed of sound were measured at temperatures ranging from (293.15 to 338.15) K, and viscosity was measured at temperatures ranging from (293.15 to 333.15) K. At 298.15 K, pure component values for heptane of 679.61 kg·m–3, 0.389 mPa·s, and 1130.1 m·s–1 for density, viscosity, and speed of sound, respectively, agree with literature values. Similarly for 2,2,4-trimethylpentane, the values of 687.70 kg·m–3, 0.501 mPa·s, and 1081.7 m·s–1 for density, viscosity, and speed of sound, respectively, agree with literature values. Density mole fraction and temperature data were fit to a second-order polynomial. Bulk moduli ranged from (551.7 to 907.1) MPa over (293.15 to 338.15) K. Viscosity mole fraction data were fit using the three-body McAllister model, while the viscosity deviations were fit to a Redlich–Kister type equation. For the mixtures, an increase in mole fraction of 2,2,4-trimethy...

Density, Viscosity, Speed of Sound, Bulk Modulus, Surface Tension, and Flash Point of Binary Mixtures of n-Hexadecane + Ethylbenzene or + Toluene at (293.15 to 373.15) K and 0.1 MPa

In this work, the physical properties of binary mixtures of n-hexadecane with toluene or ethylbenzene were measured. Density and viscosity were measured at temperatures ranging from (293.15 to 373.15) K, and the speed of sound was measured at temperatures ranging from (293.15 to 333.15) K. Density mole fraction and temperature data were fit to a fourth-order polynomial. Viscosity mole fraction data were fit using the three-body McAllister model, while the viscosity deviations were fit to a Redlich–Kister type equation. For both two-component mixtures, the speed of sound at 293.15 K decreased as the mole fraction of the aromatic compound increased until a minimum was reached after which the speed of sound increased slightly to the value of the pure aromatic compound. The bulk modulus was calculated from density and speed of sound data. For both 2-component mixtures, the bulk modulus at 293.15 K decreased slightly as the mole fraction of the aromatic compound increased until a minimum was reached after whic...

Selected physical properties of binary mixtures of crude glycerol and methanol at various temperatures

Crude glycerol, the main byproduct of biodiesel production, consists of excess methanol and other impurities and can be converted into other useful products through purification or conversion processes. In this work, dynamic viscosities, densities, excess molar volumes and refractive indexes for several mixtures of biodiesel crude glycerol and methanol with were determined at different temperatures. The physiochemical characteristics of crude glycerol in mixture form with methanol could be useful for the design of industrial equipment and purification or conversion process. The results demonstrated temperature dependent behaviors of all binary mixtures. The empirical correlations were obtained based on the experimental results.

Influence of Ethanol on the Interactions and Physical Properties of Binary Mixtures of 1-Ethyl-3-Methylimidazolium Based ILs at 298.15 K

Density (ρ), refractive index (n), conductivity (κ) and viscosity (ɳ) measurements have been carried out for binary mixtures of imidazolium based ionic liquids with ethanol at 298.15 K. Excess molar volumes have been calculated from experimental data and was fitted by Redlich-Kister equation. The density and refractive index increase with increasing ionic liquid (IL) concentration. Addition of IL leads to increased conductivity initially within these mixtures, which is subsequently followed by gradual decrease in IL-rich region showing the restricted ion mobility and enhanced interactions within these mixtures. Viscosity was found to be increase gradually with increasing IL concentration. It has been observed that solubility parameters, dielectric constant and nature of anions of ILs being used play a vital role in determining the fate of resultant properties.

Effect of high pressure microfluidization on the crystallization behavior of palm stearin - palm olein blends.

Moderate and high microfluidization pressures (60 and 120 MPa) and different treatment times (once and twice) were used to investigate the effect of high-pressure microfluidization (HPM) treatment on the crystallization behavior and physical properties of binary mixtures of palm stearin (PS) and palm olein (PO). The polarized light microscopy (PLM), texture analyzer, X-ray diffraction (XRD) and differential scanning calorimetry (DSC) techniques were applied to analyze the changes in crystal network structure, hardness, polymorphism and thermal property of the control and treated blends. PLM results showed that HPM caused significant reductions in maximum crystal diameter in all treated blends, and thus led to changes in the crystal network structure, and finally caused higher hardness in than the control blends. The XRD study demonstrated that HPM altered crystalline polymorphism. The HPM-treated blends showed a predominance of the more stable β' form, which is of more interest for food applications, while the control blend had more α- and β-form. This result was further confirmed by DSC observations. These changes in crystallization behavior indicated that HPM treatment was more likely to modify the crystallization processes and nucleation mechanisms.

Density, Viscosity, Speed of Sound, Bulk Modulus, Surface Tension, and Flash Point of Binary Mixtures of n-Dodecane with 2,2,4,6,6-Pentamethylheptane or 2,2,4,4,6,8,8-Heptamethylnonane

In this work, the physical properties of binary mixtures of n-dodecane with 2,2,4,6,6-pentamethylheptane or 2,2,4,4,6,8,8-heptamethylnonane were measured and compared to properties of four hydrotreated renewable jet (HRJ) and hydrotreated renewable diesel (HRD) fuels. Density and viscosity were measured at temperatures ranging from (293.15 to 393.15) K, and the speed of sound was measured at temperatures ranging from (293.15 to 333.15) K. For the mixtures, the speed of sound at 293.15 K decreased (1297.6 to 1285.7) m·s–1 as the mole fraction of 2,2,4,4,6,8,8-heptamethylnonane increased and decreased (1297.6 to 1203.6) m·s–1 as the mole fraction of 2,2,4,6,6-pentamethylheptane increased. The bulk modulus was calculated from density and speed of sound data. Flash points for the mixtures ranged from (318 to 367) K, and surface tension values ranged from (21.8 to 25.3) mN·m–1. When comparing to alternative fuels, two-component mixtures could be found to match the density and viscosity of HRJs and HRDs. The mixtures matched the speed of sound, bulk modulus, surface tension, and flash point of some of these hydrotreated fuels. These data suggest that binary mixtures of n-dodecane with branched alkanes may be suitable surrogates for renewable fuels.

ChemInform Abstract: Physical Properties of Binary Mixtures of ILs with Water and Ethanol

AbstractReview: 78 refs.

Phase transition and some physical properties of binary mixtures of two nematogenic compounds showing induced smectic phase

The binary mixtures of nematogenic compounds 4-n-pentyl phenyl 4-n′-hexyloxy benzoate (ME6O.5) and 4-cyanophenyl 4-pentyl benzoate (CPPB) show the presence of induced smectic phase. In this article, we report the phase diagram and the results of refractive index, density, static dielectric permittivity and X-ray diffraction measurements of different binary mixtures of (ME6O.5 + CPPB) throughout the entire composition range. The density and refractive index values have been analysed to obtain orientational order parameters. The various physical properties of the system have been discussed on the basis of the phase diagram.

Reducing Dangerous Effects of Unsymmetrical Dimethylhydrazine as a Liquid Propellant by Addition of Hydroxyethylhydrazine—Part I: Physical Properties

In this work, the effect of low volatile hydroxyethylhydrazine (HEH) as a solute on unsymmetrical dimethylhydrazine (UDMH) has been studied in order to reduce harmful effects of UDMH vapors. Desirable physical properties of binary mixtures UDMH/HEH have been measured and compared to pure UDMH. These properties include boiling point, viscosity, density, and vapor pressure that are important for using binary mixtures of UDMH/HEH as less dangerous liquid propellants. Due to the formation of strong hydrogen bonding between UDMH and HEH, the volatility of UDMH has been reduced appreciably upon the addition of HEH. It is indicated that the measured physical properties may deviate significantly compared to corresponding predicted values. Binary mixtures of UDMH/HEH can also react spontaneously in contact with nitrogen tetroxide (NTO) and red fuming nitric acid (RFNA), so they can be called hypergolic propellants.

Physical Properties of Binary Mixtures of Ethyl Formate with Benzene, Isopropyl Benzene, Isobutyl Benzene, and Butylbenzene at (303.15, 308.15, and 313.15) K

Densities, viscosities, and speeds of sound of binary mixtures of ethyl formate with benzene, isopropyl benzene, isobutyl benzene, and butylbenzene have been measured over the entire range of composition, at (303.15, 308.15, and 313.15) K and at atmospheric pressure. The excess volume, VE, deviation in viscosity, Δη, and deviation in isentropic compressibility, ΔKs, have been calculated from the experimental values of density, viscosity, and ultrasonic velocity. The excess volumes are positive, while the deviations in viscosities are negative for all of the studied binary systems over the whole composition range. The deviation in isentropic compressibility shows both positive and negative deviations for ethyl formate with benzene and isopropyl benzene, and for the remaining systems they are positive. The ability of some of the empirical models to calculate mixing viscosities was also tested.

Thermo physical properties of binary mixtures of n-butylamine with alkyl acetates at 303.15 K

Excess volumes, speeds of sound and viscosities were measured for binary mixtures of n-butylamine (NBA) with methyl acetate (MA), ethyl acetate (EA), butyl acetate (BA) and isoamyl acetate (IAA) at 303.15 K over the entire range of composition. Isentropic compressibilities were computed from speed of sound and density data. Densities were obtained from experimental excess volume data in case mixtures. Speeds of sound were evaluated using Jacobson free length theory (FLT) and Schaaffs collision factor theory (CFT). The viscosity data were analyzed on the basis of corresponding states approach and Grunberg and Nissan treatment. The experimental results on excess volume, deviation in isentropic compressibility and in viscosity were discussed in terms of molecular interactions between unlike molecules. A Redlich–Kister type equation was used to fit the experimental data on excess volume, deviations in compressibility and viscosity.

Physical Properties of Binary Mixtures of the Ionic Liquid 1-Ethyl-3-methylimidazolium Ethyl Sulfate with Several Alcohols at T = (298.15, 313.15, and 328.15) K and Atmospheric Pressure

In this contribution, dynamic viscosities, densities, and speeds of sound of 1-ethyl-3-methylimidazolium ethyl sulfate (EMISE) with methanol, 1-propanol, and 2-propanol at T = (298.15, 313.15, and 328.15) K and refractive indices at T = 298.15 K and at atmospheric pressure have been measured over the whole composition range. Excess molar volumes, excess molar isentropic compressions, and viscosity deviations for the binary systems from T = 298.15 K to T = 328.15 K and refractive deviations at 298.15 K have been calculated and were satisfactorily fitted to a Redlich−Kister equation to give the fitting parameters and the root-mean-square deviations.

Physical Properties of Binary Mixtures of the Ionic Liquid 1-Methyl-3-octylimidazolium Chloride with Methanol, Ethanol, and 1-Propanol at T = (298.15, 313.15, and 328.15) K and at P = 0.1 MPa

In this work, dynamic viscosities, densities, and speed of sound of 1-methyl-3-octylimidazolium chloride, [C8mim][Cl], with methanol, ethanol, and 1-propanol at T = (298.15, 313.15, and 328.15) K and refractive index at T = 298.15 K and P = 0.1 MPa have been measured over the whole composition range. Excess molar volumes, isentropic compressibility deviations, and viscosity deviations for the binary systems from T = (298.15 to 328.15) K were calculated. These results were fitted to a Redlich−Kister equation to determine the fitting parameters and the root mean square deviations.