Binary Mixtures Of Propylene Carbonate Research Articles

Exploring relaxation behaviors in Hydrogen-Bond networks within binary mixtures of propylene carbonate and primary alcohols through broadband dielectric spectroscopy and molecular dynamic simulation

This work investigates the dielectric properties and the relaxation behaviors of propylene carbonate (PC) and its binary mixtures with methanol and ethanol. A coaxial-circular cutoff waveguide junction was employed to characterize broadband dielectric spectra ranging from 0.1 GHz to 18 GHz, and a two-group Debye model was used to extract relaxation parameters. Excess thermodynamic parameters, Kirkwood orientational correlation factors, and Bruggeman factors for PC-alcohol mixtures were also analyzed and presented. These data provide insights into microscopic dynamic processes as the PC concentration in the mixtures gradually increases. These processes include the continuous disassociation of the alcohols’ hydrogen-bond (H-bond) networks, the formation of new PC-alcohol H-bond networks, the parallel alignment of heterogeneous dipoles, and a significant enhancement of the dielectric effect. Furthermore, a series of molecular dynamics (MD) simulations using the TraPPE-UA forcefield were conducted, and the obtained thermodynamic and electromagnetic parameters demonstrated good agreement with experimental results. Based on radial distribution functions, dipole–dipole spatial orientational correlations, and H-bond life times extracted from the MD simulations, we observed the gradual formation of PC-cage and alcohol-cluster microstructures in PC-rich mixtures. The data and physical insights provided in this work are expected to have practical implications in high-energy battery applications and the pharmaceutical industry.

Intermolecular Interaction for Binary Mixtures of Propylene Carbonate with Acetonitrile, Dimethyl Carbonate, Diethyl Carbonate at Different Temperatures: Density and Viscosity

Abstract In this work, the experimental densities and viscosities have been determined for (propylene carbonate+acetonitrile, or dimethyl carbonate, or diethyl carbonate) binary mixtures over the whole concentration range at temperatures (293.15–333.15 K) and the atmospheric pressure. Excess molar volumes (VE ), viscosity deviations (Δη), thermal expansion coefficients (α) and excess Gibbs free energy of activation of viscous flow (ΔGE *) were calculated. These excess functions and deviations were fit with the Redlich–Kister type polynomial equation. The sign and magnitude of these excess properties have been used to interpret the results in terms of intermolecular interactions and structural effects. The results obtained for viscosity of binary mixtures were also used to test the semi-empirical relations of Grunberg-Nissan and Katti-Chaudhri equations.

Characterization of conductivity relaxation processes induced by charge dynamics and hydrogen-bond molecular interactions in binary mixtures of propylene carbonate with acetonitrile

Abstract The complex dielectric permittivity, alternating current electrical conductivity, electric modulus and impedance spectra of the binary mixtures of propylene carbonate with acetonitrile have been investigated by employing dielectric relaxation spectroscopy over the frequency range from 20 Hz to 1 MHz at 25 °C. It is found that the real part of dielectric permittivity represents the static dielectric permittivity of these mixtures in the frequency range from 100 kHz to 1 MHz, whereas it starts to increase sharply from static permittivity value and reaches up to five orders of magnitude with the decrease of frequency from 20 kHz to 20 Hz. This behaviour confirms the dominant contribution of absorbed charge contaminants in the dielectric polarization of these dipolar liquids at low frequencies. The electric modulus and impedance spectra of these binary mixtures exhibit the Debye-type dispersion behaviour. Electric double layers and conductivity relaxation processes induced in these mixtures exhibit non-linear behaviour with the mole fraction concentration of the mixtures constituents and the relaxation times of these processes have proportionality with dc electrical conductivity. The static dielectric permittivity, refractive index and excess properties of these dielectric parameters over the entire mixing concentration range of the binary mixtures with temperature variations from 15 °C to 45 °C have also been determined. Results confirm that the heterogeneous intermolecular hydrogen-bond with parallel dipolar ordering is formed between propylene carbonate and acetonitrile in the mixtures. The conductivity activation energy values have been determined from the Arrhenius plots, which have an increase with the increase of propylene carbonate concentration in the binary mixtures.

Dependency of polyelectrolyte solvent composition on electrochromic photopic contrast

Herein, we present a versatile way to increase the photopic contrast of electrochromic devices (ECDs), approximately 14%, through the use of binary mixtures of propylene carbonate, diethyl carbonate, and ethylene carbonate that serve the role as plasticizers in the gel electrolyte. The binary plasticizer mixture changed the physical properties of the gel electrolyte medium, including the viscosity and dielectric constant, and also facilitates the diffusion of ions and monomer in the medium leading to an increase in ionic conductivity and the photopic contrast. ECDs were fabricated using a one-step lamination procedure, based on poly(2,2-dimethyl-3,4-propylenedioxythiophene) (PProDOT-Me2) with different polymer gel electrolyte compositions where the electrochromic polymer was electrochemically obtained in situ. Gel electrolytes based on unary or binary plasticizer systems and poly(ethylene glycol) diacrylate (PEG-DA) with varying lithium trifluoromethanesulfonate (LiTrif) loading were investigated for the effect of solvent on ionic conductivity and the resulting photopic contrast of the ECD. This study demonstrates a relationship between photopic contrast and ionic conductivity, where the system reaches a maximum in photopic contrast the system is also at the maximum ionic conductivity.

Dielectric constants of binary mixtures of propylene carbonate with dimethyl carbonate and ethylene carbonate from molecular dynamics simulation: comparison between non-polarizable and polarizable force fields

Using non-polarizable and polarizable molecular dynamics simulations, binary mixtures of propylene carbonate + dimethyl carbonate and propylene carbonate + ethylene carbonate with various compositions were investigated. The polarizable model produces more reasonable estimation of dielectric constants than the non-polarizable model; however, combining the electronic continuum model with the non-polarizable MD improves the comparison between the two models. Fair agreement was found between the results from these simulations and available experimental data. In addition, for a better understanding of the mixing behaviour, the excess dielectric constants over the entire composition were calculated. By comparison of the two mixtures in various mole fractions, distinctive mixing behaviours of propylene carbonate + dimethyl carbonate (poorly symmetric mixture) and propylene carbonate + ethylene carbonate (highly symmetric mixture) were observed.

Thermodynamic and dynamic properties in binary mixtures of propylene carbonate with dimethyl carbonate and ethylene carbonate

Molecular dynamics simulations of binary mixtures of propylene carbonate (PC)+dimethyl carbonate (DMC) and PC+ethylene carbonate (EC) with various compositions were performed to study thermodynamic and dynamic properties such as density, dielectric constant and self-diffusion coefficient. For a better understanding of the thermodynamic behavior of the mixtures, the excess molar volume and excess dielectric constant with the various mole fractions were calculated. In addition, a computational approach of the Molecular Dynamics with Electronic Continuum (MDEC) model combined with density functional theory was used to determine the dielectric constants. Fair agreement was found between the results from our simulations and available experimental data. By comparison of the two mixtures observed in various mole fractions, the thermodynamic and dynamic behaviors of PC+DMC were highly asymmetrical whereas those of PC+EC were nearly symmetrical.

Isentropic Compressibility for Binary Mixtures of Propylene Carbonate with Benzene and Substituted Benzene

Ultrasonic velocities (u) for binary mixtures of propylene carbonate (PC) (1) with benzene and substituted benzenes (2) viz. benzene, ethylbenzene, o-xylene and p-xylene have been measured at 288.15-308.15 K over the entire range of composition. The experimental values of ultrasonic velocities (u) have been utilized to calculate isentropic compressibility (), intermolecular free length (), acoustic impedance (Z).

Viscosity Behavior of Some Oxygen Containing Compounds

Densities (ρ) and viscosities (η) for the binary mixtures of propylene carbonate with tetrahydrofuran (THF), 1,4-dioxane, and acetylacetone were measured over the entire mole fraction range at (288.15, 298.15, and 308.15) K. The results are discussed in the light of intermolecular interactions present among the components.

Densities and viscosities of propylene carbonate with aromatic hydrocarbons (benzene, 1,4-dimethylbenzene and ethylbenzene) at 288.15, 298.15 and 308.15 K

Densities and viscosities of the binary mixtures of propylene carbonate with benzene, 1,4-dimethylbenzene and ethylbenzene were measured over the entire mole fraction range at 288.15, 298.15 and 308.15 K. Using the experimental values of densities and viscosities the excess molar volumes and viscosity deviations were calculated. The results were fitted by Redlich–Kister equation. The results were discussed in terms of intermolecular interactions.

Densities and ultrasonic velocities of some oxygen containing compounds

Densities ( ρ) and ultrasonic velocities ( u) of binary mixtures of propylene carbonate with tetrahydrofuran (THF), 1,4-dioxane, acetylacetone and acetone have been measured at 288.15, 298.15 and 308.15 K. From these measurements excess molar volumes ( V E ), isentropic compressibility ( κ s ), specific acoustic impedance ( Z), intermolecular free length ( L f ), excess isentropic compressibility (Δ κ s ), excess specific acoustic impendence ( Z E ) and excess intermolecular free length ( L f E ) were calculated. These results were fitted to Redlich–Kister polynomial. The results were discussed in terms of molecular interactions.

Molecular Interactions in Propylene Carbonate + n-Alkanols at 25 ∘C

Densities and viscosities of the binary mixtures of propylene carbonate with methanol, ethanol, propanol, butanol, and hexanol, along with those of the pure liquids, were measured over the entire mole fraction range at 25 ∘C. Using the experimental values of densities ρ and viscosities η, the excess molar volumes VE, viscosity deviations Δη, excess Gibbs energies of activation of viscous flow ΔGE, and Grunberg–Nissan interaction parameters d12 were calculated from the linear dependence of these parameters on the composition of the mixtures.

Viscosities and Excess Molar Volumes of Binary Mixtures of Propylene Carbonate with Tetrahydrofuran and Methanol at Different Temperatures

Densities and viscosities of the binary mixtures of propylene carbonate with methanol and tetrahydrofuran have been measured at (298.15, 308.15, and 318.15) K. The excess molar volumes and the deviations of the viscosity of the mixture from the ideal mole fraction rule have been calculated from these data. The computed results have been fitted to the Redlich−Kister polynomial relation to estimate the regression coefficients and standard errors for these systems.

Excess Enthalpies and Excess Volumes of the Liquid Binary Mixtures of Propylene Carbonate + Six Alkanols at 298.15 K

The excess molar enthalpies and the excess molar volumes for binary mixtures of propylene carbonate with methanol, ethanol, 1- and 2-propanol, and 1- and 2-butanol have been determined as a function of composition at 298.15 K and atmospheric pressure, using an LKB flow microcalorimeter and an Anton Paar density meter. The excess enthalpies are positive for all mixtures, while excess volumes are negative for methanol and ethanol, positive for 1- and 2-butanol and show a change of sign, as a function of composition, for 1- and 2-propanol. Both excess properties increase in magnitude as the alkanol chain length increases. Results were correlated by means of the Redlich−Kister equation and a qualitative molecular interpretation is presented.

The passivity of iron in mixtures of propylene carbonate and water

The passivation of Fe in binary mixtures of propylene carbonate and water containing 0.5 M LiClO 4 has been investigated over the entire range of water-PC composition. While Fe was found to passivate in both totally aqueous and anhydrous solutions, over much of the composition range in between an unstable passivity was observed which led to localized attack of the surface. A passive film formed in aqueous solution was found to be stable upon exposure to the mixed solutions, though a removal of this film by cathodic reduction created bare surface sites which, when polarized to the original passive film formation potential, suffered from a pitting attack. These observations are explained in terms of the competition between the different passivation mechanisms for the organic and aqueous cases leading to localized metal loss because neither passivation mechanism can dominate in the solution mixtures.