Bruggeman Parameter Research Articles

Complex and thermodynamic properties of polar liquids using time domain reflectometry

The study of complex properties in a binary mixture of 1,2-dichloroethane (DE) and [Formula: see text]-methylformamide (NMF) polar liquids has been carried out in the frequency range of 10[Formula: see text]MHz to 30[Formula: see text]GHz for 11 different concentrations using time domain reflectometry technique at 283, 288, 293 and 298[Formula: see text]K temperatures. Complex property of binary liquids indicates the type of distribution of the dielectric relaxation time. The Bruggeman parameter gives the information about molecular interactions within binary polar liquids. Thermodynamic parameter deals with the passing of a dipole across a potential barrier which separates the minima of energy.

Microwave dielectric relaxation spectroscopy study of propylene glycol/ethanol binary mixtures: Temperature dependence

Complex dielectric permittivity measurements of propylene glycol (PG) in ethanol at various mole fractions were measured by using open-ended coaxial probe technique at different temperatures in the frequency range 0.02<ν/GHz<20. The dipole moment (μ), excess dipole moment (Δμ),excess permittivity (εE), excess inverse relaxation time(1/τ)E, Bruggeman parameter (fB), excess Helmholtz energy (ΔFE) are determined using experimental data. From the minimum energy based geometry optimization, dipole moments of individual monomers of propylene glycol and ethanol and their binary system have been evaluated theoretically at gaseous state as well as alcoholic medium by using PCM and IEFPCM solvation models from the Hatree-Fock (HF) and Density Functional Theory (DFT-B3LYP) methods with 6-311G* and 6-311G** basis sets. The obtained results have been interpreted in terms of the short and long range ordering of the dipoles, Kirkwood correlation factor (geff), thermodynamic parameters, mean molecular polarizability (αM) and interaction in the mixture through hydrogen bonding.

Study of Molecular Interaction in Binary Mixtures (1-Propanol + Acetophenone)

Studies on Physico-chemical properties of binary liquid mixtures provide information on the nature of interactions between the constituent of the binaries. Literature provides extensive data on the static dielectric constant (ε0) and refractive index (n) of liquid compounds, but the combined study of all is quite scarce. In the present work static dielectric constant (ε0) and refractive index (n) have been experimentally determined for binary liquid mixture of 1-Propanol (PrOH) with Acetophenone (ACP) over the entire concentration range of mixture composition (0.0 →1.0) at constant temperature 303 K. Static dielectric constant (ε0) and refractive index (n) for the binary mixture have been measured using high precision LCR meter (0.2 MHz) and Abbe’s refractometer respectively. Excess of static dielectric constant (ε0)E and refractive index (n)E are determined and fitted with Redlich-Kister polynomial equation to derive the binary coefficients and standard deviations. For interaction and structural information various parameters namely, Kirkwood correlation factor (g), Kirkwood effective correlation factor (geff), Kirkwood angular correlation factor (gF) and Bruggeman parameter (fB) are determined for the binary mixtures. Variations of these parameters against the concentration of constituents are discussed in terms of molecular interaction between the constituent species.

Temperature-dependent microwave dielectric relaxation studies of hydrogen bonded polar binary mixtures of propan-1-ol and propionaldehyde

The molecular interaction between the polar systems of propan-1-ol and propionaldehyde for various mole fractions at different temperatures were studied by determining the frequency dependent complex dielectric permittivity by using the open-ended coaxial probe technique method in the microwave frequency range from 20MHz to 20GHz. The geometries are optimized at HF, B3LYP and MP2 with 6-311G and 6-311G+ basis sets. Dipole moments of the binary mixtures are calculated from the dielectric data using Higasi’s method and compared with the theoretical results. Conformational analysis of the formation of hydrogen bond between the propan-1-ol and propionaldehyde is supported by the FT-IR and molecular polarizability calculations. The average relaxation times are calculated from their respective Cole–Cole plots. The activation entropy, activation enthalpy and Kirkwood correlation ‘g’ factor, excess permittivity (εE), excess inverse relaxation time (1/τ)E, Bruggeman parameter (fB) have also been determined for propan-1-ol and propionaldehyde and the results were correlated.

A Study of Molecular Interaction in Binary Mixtures of 1-Propanol with N,N-Dimethylformamide at Different Temperatures

The static dielectric constant (ε0) and optical dielectric constant (ε = n2) of binary mixtures of 1-Propanol (1-PrOH) with N,N-Dimethylformamide (DMF) of different concentrations, prepared by volume fractions (0.0, 0.1, . 1.0) are measured at 2 MHz using precision LCR meter and Abbes refractometer respectively at different temperatures. The excess dielectric constant (ε0)E, Kirkwood correlation parameters (geff, gF), Bruggeman parameter (fB) are evaluated. The variations of these parameters with concentration and temperature are discussed in terms of molecular interaction between the molecular species of constituting components in these mixtures.

Dielectric relaxation, thermodynamic and theoretical studies on hydrogen bonded polar binary mixtures of N-methyl aniline with propan-1-ol and isopropyl alcohol

The dielectric relaxation studies on polar binary mixtures of N-methyl aniline with, alcohols, propan-1-ol and isopropyl alcohol have been carried out, at different temperatures and mole fractions, using — LF impedance analyzer, Plunger method and Abbe’s refractometer in radio, microwave and optic frequency regions respectively. Kirkwood effective correlation factor, corrective Kirkwood correlation factor, Bruggeman parameter, relaxation time and thermodynamical parameters are calculated using the experimental data. Conformational analysis of the formation of hydrogen bond in the equi molar binary mixture systems of N-methyl aniline with propan-1-ol and isopropyl alcohol is supported by experimental and theoretical FT-IR values.

Thermodynamic, Dielectric and Conformational Studies on Hydrogen Bonded Binary Mixtures of Propan-1-ol with Methyl Benzoate and Ethyl Benzoate

Dielectric relaxation studies of propan-1-ol with alkyl benzoates (methyl benzoate and ethyl benzoate) have been carried out, for various mole fractions, at different temperatures using a LF impedance analyzer, Plunger method, and an Abbe’s refractometer in the radio, microwave and optical frequency regions, respectively. Kirkwood’s effective correlation factor, the corrective Kirkwood correlation factor, Bruggeman parameter, relaxation time, excess inverse relaxation time and thermodynamic parameters were calculated using the experimental data. Conformational analysis of the formation of hydrogen bonds in the equi-molar binary mixtures of propan-1-ol with alkyl benzoates is supported by experimental and theoretical FT-IR values.

Conformational and dielectric relaxation studies on hydrogen bonded binary mixture of isopropyl alcohol in methyl benzoate and ethyl benzoate

The dielectric relaxation study for the hydrogen bonded binary system of polar liquid isopropyl alcohol in non-associated liquids – methyl benzoate and ethyl benzoate has been carried out, using the HP–LF impedance analyzer in static region, Plunger method in microwave frequency region and Abbe’s refractometer in optic region, at different temperature and mole fractions. The dielectric parameters viz. static, optic permittivity, excess permittivity, Bruggeman parameter, relaxation time, excess inverse relaxation time and thermodynamic parameters have been obtained. The dielectric parameters show systematic change with temperature and concentrations. Conformational analysis of the formation of hydrogen bond in the binary mixture systems isopropyl alcohol with methyl benzoate and ethyl benzoate is supported by FT-IR. Hamiltonian quantum mechanical calculations such as AM1, PM3 and MNDO optimized converged geometry operation is performed by using Spartan Modeling software for both pure and equi molar systems and thus the FT-IR spectra are obtained and further compared with the experimental values.

Dielectric and thermodynamic behaviour of binary mixtures of anisole with o-chlorophenol and with o-cresol

The molecular interactions in binary mixtures of anisole with o-chlorophenol and o-cresol have been studied at three different temperatures using dielectric measurements. The static permittivity and the permittivity at optical frequency have also been determined and used to obtain the Kirkwood correlation factors, the Bruggeman parameter, the excess permittivity and the excess free energy for different concentrations of two binary mixtures, namely (1) anisole + o-chlorophenol and (2) anisole + o-cresol. Using the effective Kirkwood correlation factor, parallel and anti-parallel alignments among the dipoles are identified. The corrective Kirkwood correlation factor, the excess permittivity and the Bruggeman parameter are used to explain the interaction between unlike molecules. The temperature dependences of the above parameters are also reported. The investigation shows systematic changes in the dielectric behaviour with variations in concentration and temperature.

Concentration and temperature dependent interaction studies using dielectric and thermodynamic methods on mixtures of anisole with o-toluidine and m-toluidine

Molecular interactions in mixtures of anisole with o-toluidine and anisole and m-toluidine have been studied at three different temperatures using the dielectric method with measurements of the static permittivity and permittivity at optical frequency. From the measured values, the Kirkwood correlation parameter, Bruggeman parameter, excess permittivity and thermodynamic excess free energy were computed for the mixtures. Positive and negative values of excess permittivity were obtained for both mixtures. The excess free energy for the anisole+o-toluidine mixture is positive at all three temperatures, whereas mixed values (positive and negative) are obtained for the anisole+m-toluidine mixture. Alignment of the dipoles in both mixtures was identified by Kirkwood factors. The investigation shows that the interaction between the components changes systematically with concentration and temperature and the change is minimum.

Dielectric and thermodynamic studies on a binary mixture of anisole with butyric or caprylic acid

The molecular interaction of anisole with fatty acids, such as butyric acid and caprylic acid, has been studied using standard dielectric methods. The permittivity at static and optical frequency (the sodium D-line) of a mixture of anisole + butyric acid and anisole + caprylic acid were measured at three different temperatures. Kirkwood correlation parameters, the excess permittivity, the Bruggeman parameter and excess free-energy were determined for each concentration of the mixture. A positive value of excess permittivity was obtained for the mixture of anisole + butyric acid, whereas for most concentrations of the anisole + caprylic acid mixture, the excess permittivity was negative at all studied temperatures. Negative and positive values of the Bruggeman parameters were obtained for the anisole + butyric acid and anisole + caprylic acid mixtures, respectively. Parallel and anti-parallel alignments of dipoles in the mixtures were identified.

An Investigation on the Molecular Dynamics of Binary Mixtures of Anisole with Acetic and Propionic Acids

Temperature dependent dielectric studies were carried out from 303 to 323 K for mixtures of anisole with acetic acid and with propionic acid, in order to investigate the molecular dynamics of these molecules. The low-frequency molecular dynamics of these molecules have been studied by computing some dielectric parameters such as the Kirkwood correlation factor, Bruggeman parameter, excess permittivity and excess Helmholtz energy. The observed Kirkwood effective correlation factor for both binary mixtures at all concentrations and temperatures were found to be less than unity. Negative values of the Bruggeman parameter were obtained for mixtures of anisole with acetic acid whereas positive values were obtained for the mixtures of anisole with propionic acid. The formation of β-multimers, with anti-parallel dipolar orientations, was identified in the above binary mixtures. This investigation showed that changes of temperature did not produce any significant structural changes over the studied temperature interval.

Dielectric and thermodynamic behavior of binary mixture of anisole with morpholine and aniline at different temperatures

The interaction between the molecules of anisole with morpholine and aniline was studied at static frequency. Static permittivity at three different temperatures was computed for the mixture of anisole with morpholine and aniline. Permittivity at static frequency and at optical frequency was measured at different concentrations of the mixtures at different temperatures and they were used to calculate dielectric parameters such as Kirkwood correlation factor, excess permittivity, Bruggeman parameter, and thermodynamic parameters (Gibbs free energy). These parameters were used to carry out temperature dependent dielectric studies on the mixtures. The investigation showed a systematic change in dielectric parameters of the systems with the change in concentration and temperature.

Studies on molecular interactions and fluid structure of anisole with 2-ethyl-1-hexanol and decyl alcohol

The dielectric studies of a liquid can give information on its structure and interaction. Dielectric study of anisole has been carried out by mixing it with alcohols namely 1) 2-ethyl-l-hexanol and 2) decyl alcohol at different temperatures. The Kirkwood correlation factor, the excess dielectric permittivity, Bruggeman parameter and the thermodynamic properties of the mixtures have been determined and the results are interpreted. The interaction between like molecules is explained with the Kirkwood correlation parameter and the interaction between the unlike molecules is identified by the excess parameters and Bruggemann parameter. Values of Kirkwood correlation factor, excess static permittivity, Bruggeman parameter and the thermodynamic parameters are found to depend on the concentration and temperature of the mixtures. The parallel and anti-parallel orientations among the dipoles are analysed.