Dielectric Relaxation Study of Liquids Having Chloro Group with Associated Liquids. I. Chlorobenzene with Methanol, Ethanol, and 1Propanol (original) (raw)
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Journal of Solution Chemistry, 2002
Frequency spectra of the complex permittivity for 1,2-dichloroethane–alcohol binary mixtures have been determined over the frequency range 10 MHz to 20 GHz at 15, 25, 35, and 45°C, using the time-domain reflectometry (TDR) technique, for 11 compositions of each 1,2 dichloroethane–alcohol system. The alcohols used in the study were methanol, ethanol, and 1-propanol. The relaxation in these systems can be described by a single relaxation time using the Debye model. The static dielectric constant, relaxation time, the corresponding excess dielectric properties, Kirkwood correlation factor, and Bruggeman factor of the mixtures have been determined. The static dielectric constants for the mixtures have been fitted with the modified Bruggeman model.
Mediterranean Journal of Chemistry, 2011
In this work, our objective was to study the complex permittivity of binary mixtures of water-ethanol, water-methanol and methanol-ethanol with various mole fractions at temperature between-35 and 35 °C. Measurements were made in the frequency domain from 300 kHz to 1.3 GHz by means of an open ended coaxial line technique coupled to a network analyzer. Water-ethanol and water-methanol mixtures display a Kraszewski Law while methanol-ethanol mixture shows a Shivola-Kong Law. The static dielectric constant, ε s were obtained from the plateau of ε'(ω) curve, in water rich mixture or alcohol rich mixture has similar real permittivity ε' of pure liquids. The values of ε s mixtures increase by decreasing the temperature assigned to the cooperative dynamics H-bond system in mediums. The validity of permittivity measurements according to the temperature are verified by the Queen-King Law and the) 2 0 ( j j A constants are compared with literature data. The dielectric relaxation behaviour of water-ethanol mixture can be better described with a Cole-Davidson function while for methanol-ethanol one, a Debye function gives a good fit. At 25 °C, the relaxation time in the aqueous mixtures of ethanol and methanol sharply increased with increasing alcohol concentration.
Zeitschrift für Naturforschung, 2008
Dielectric relaxation of different molar concentrations of ethanol (C 2 H 5 OH) in binary mixtures of ethanol and chlorobenzene in benzene solutions has been studied at 9.883 GHz by using standard standing microwave techniques and Gopala Krishna's single frequency concentration variation method at different temperatures (25 • C, 30 • C, 35 • C, and 40 • C). It was found that the dielectric relaxation time varies linearly with variation in the molar concentration of ethanol in the whole concentration range of the binary mixture. Based upon these results the absence of solute-solute and the presence of solute-solvent type of molecular associations could be assumed. The energy parameters for the dielectric relaxation process of binary mixtures containing 50 mol% of ethanol have been calculated at the given temperatures. Comparison has been made with the corresponding energy parameters for viscous flow processes. It was found that the dielectric relaxation process can be treated as the rate process like the viscous flow process.
Zeitschrift für Physikalische Chemie, 2006
The dielectric relaxation studies of different molar concentrations of ethanol in the binary mixtures of ethanol and N, N-dimethylacetamide in benzene solutions have been studied at 9.883 GHz by using standard standing microwave techniques and Gopala Krishna's [Trans Faraday Soc, 33 (1957) 767] single frequency concentration variation method at different temperatures (25, 30, 35 and 40°C). It is found that dielectric relaxation time varies non-linearly with the variation in molar concentration of ethanol in the whole concentration range of the binary mixture. The solute-solute and solutesolvent types of molecular associations have been proposed. The energy parameters (ΔH ε , ΔF ε , ΔS ε) for the dielectric relaxation process of binary mixtures containing 50% molar concentration of ethanol have been calculated at the respective given temperatures. Comparison has been made with the corresponding energy parameters for viscous flow process. It is found that the dielectric relaxation process can be treated as the rate process like the viscous flow process.
Indian Journal of Pure & Applied Physics, 2007
Dielectric constant (ε′) and dielectric loss (ε″) of ethanol (C 2 H 5 OH) and binary mixtures of ethanol and N, Ndimethylformamide (DMF) in benzene solutions have been measured at microwave frequency 9.883 GHz at different temperatures 25, 30, 35 and 40°C. Standing microwave techniques and Gopala Krishna's [Trans Faraday Soc, 33 (1957)767.] single frequency concentration variation method have been used for above measurements. The measured values of ε′ and ε″ have been used to evaluate dipole moment (µ) and relaxation time (τ). Various thermodynamic parameters (∆H ε , ∆F ε , and ∆S ε) for the dielectric relaxation process of binary mixtures containing 50% mole fraction of OH have been calculated using Eyring's rate equations. Comparison has been made with the corresponding energy parameters for viscous flow process. It is found that the dielectric relaxation process can be treated as the rate process like the viscous flow process. Non-linear variation of relaxation time with molar concentration of ethanol in the whole concentration range of the binary mixture indicates the existence of solute-solute type of molecular association.
Complex permittivity spectra of binary mixtures of varying concentrations of-picoline and Methanol (MeOH) have been obtained using time domain reflectometry (TDR) technique over frequency range 10 MHz to 25 GHz at 283.15, 288.15, 293.15 and 298.15 K temperatures. The dielectric relaxation parameters namely static permittivity (" 0), high frequency limit permittivity (" 11) and the relaxation time () were determined by fitting complex permittivity data to the single Debye/Cole-Davidson model. Complex nonlinear least square (CNLS) fitting procedure was carried out using LEVMW software. The excess permittivity (" E 0) and the excess inverse relaxation time (1/Þ E which contain information regarding molecular structure and interaction between polar–polar liquids were also determined. From the experimental data, parameters such as effective Kirkwood correlation factor (g eff), Bruggeman factor (f B) and some thermo dynamical parameters have been calculated. Excess parameters were fitted to the Redlich–Kister polynomial equation. The values of static permittivity and relaxation time increase nonlinearly with increase in the mol–fraction of MeOH at all temperatures. The values of excess static permittivity (" 0 E) and the excess inverse relaxation time (1/Þ E are negative for the studied-picoline — MeOH system at all temperatures.
Indian Journal of Pure & Applied Physics, 2008
The dielectric relaxation studies of different molar concentrations of ethanol in the binary mixtures of ethanol and N, N-dimethylacetamide in benzene solutions have been studied at 9.883 GHz by using standard standing microwave techniques and Gopala Krishna's [Trans Faraday Soc, 33 (1957) 767] single frequency concentration variation method at different temperatures (25, 30, 35 and 40°C). It is found that dielectric relaxation time varies non-linearly with the variation in molar concentration of ethanol in the whole concentration range of the binary mixture. The solute-solute and solutesolvent types of molecular associations have been proposed. The energy parameters (ΔH ε , ΔF ε , ΔS ε) for the dielectric relaxation process of binary mixtures containing 50% molar concentration of ethanol have been calculated at the respective given temperatures. Comparison has been made with the corresponding energy parameters for viscous flow process. It is found that the dielectric relaxation process can be treated as the rate process like the viscous flow process.
Microwave Dielectric Relaxation of Alcohols in non polar solutions
IOSR Journal of Applied Physics, 2014
The properties of the binary mixtures of 1-propanol and phenol have been studied at constant temperature 303K in dilute solutions of benzene using standard standing wave microwave X-band (9.4 GHz) Jband (7.4 GHz) technique. The values of different dielectric parameters ε 0 , ε', ε'', ε ∞ have been determined for five different mole fractions of 1-propanol and phenol. The values of permittivity and dielectric loss are used to evaluate relaxation time for overall molecular rotation (τ 1), relaxation time for intermolecular rotations (τ 2), most probable relaxation time (τ 0) and dipole moment (µ) at constant temperature 303K. The values of relaxation times and dipole moment are found to increases with the mole fraction of 1-propanol, phenol in all binary mixtures. The energy parameter (ΔFτ) for dielectric relaxation process of the mixtures is also calculated. It is found that the dielectric relaxation process can be treated as a rate process. The present investigation suggest that existence of both the intermolecular and intramolecular orientation takes place in both binary mixtures.