Dielectric Relaxation of the Butyl Alcohols in p-Xylene Solution

1971 ◽  
Vol 49 (5) ◽  
pp. 712-718 ◽  
Author(s):  
John Crossley
Keyword(s):  
Dielectric Relaxation ◽  
Relaxation Times ◽  
Alcohol Concentration ◽  
Dielectric Constants ◽  
Pure Liquid ◽  
Frequency Range ◽  
Concentrated Solutions ◽  
Polar Solvents ◽  
Symmetrical Distribution ◽  
Xylene Solution

Dielectric constants and losses of the four butyl alcohols have been measured at concentrations of 0.02–0.12 mol fraction in p-xylene solution over the frequency range 1–35 GHz at 25 °C. The data for the most dilute solutions can be represented by a symmetrical distribution of relaxation times. For the mole concentrated solutions the Cole–Cole plots indicate a separation into two absorption regions and the data can be analyzed in terms of two relaxation times both of which lengthen with increased alcohol concentration. The contribution from the long relaxation time and the apparent dipole moment for each butanol, is independent of alcohol concentration and decreases in the order n-butanol > iso-butanol > sec-butanol > t-butanol. The results are discussed in terms of previous dielectric relaxation studies of pure liquid aliphatic alcohols and their solutions in non-polar solvents.

Dielectric and Association Behavior of 1-Propanol, 2-Propen-1-ol, and 2-Propyn-1-ol in Non-polar Solvents

1972 ◽  
Vol 50 (1) ◽  
pp. 99-103 ◽  
Author(s):  
G. E. Rajala ◽  
J. Crossley
Keyword(s):  
Relaxation Times ◽  
Low Frequency ◽  
Alcohol Concentration ◽  
Dielectric Constants ◽  
Polar Solvents ◽  
Association Behavior

Dielectric constants and losses of 1-propanol, 2-propen-1-ol, and 2-propyn-1-ol in p-xylene, and 1-propanol and 2-propen-1-ol in cyclohexane have been measured at up to 10 frequencies in the range 1–145 GHz at 25 °C. The low frequency dielectric constants have also been measured at 2 MHz. An analysis in terms of two relaxation times has been obtained for each system. The short relaxation times are relatively independent of the alcohol, its concentration, and the solvent. Conversely, the longer relaxation times lengthen with increased alcohol concentration, lengthen in the order 2-propyn-1-ol, 2-propen-1-ol, 1-propyn-1-ol and are considerably shorter in p-xylene than in cyclohexane.

scholarly journals Dielectric Relaxation in Temperate Glaciers

1967 ◽  
Vol 6 (48) ◽  
pp. 897-909 ◽  
Author(s):  
P. W. F. Gribbon
Keyword(s):  
Dielectric Relaxation ◽  
Loss Factor ◽  
Relaxation Times ◽  
Frequency Range ◽  
Spreading Factor ◽  
Cold Surface ◽  
Relative Temperature ◽  
Low Frequencies ◽  
Glacial Ice ◽  
Impurity Ion

The dielectric relaxation ofnévéand glacial ice has been studied on two temperate glaciers in Greenland and France. Measurement of the capacitance and loss tangent in the audio-frequency range of thin parallel wires placed on the surface of a glacier gaveϵ′, the relative permittivity, andϵ″, the loss factor of thenévé. The relaxation time can be expressed in terms of the frequencyfmat the maximumϵ″ value of the Cole-Coleϵ″−ϵ′ diagram, and its variation with depth was derived from the Cole-Cole diagrams obtained for different wire separations.For wet 0°C. surface snow in Greenland,fm≈ 4 kHz. and decreased with the increase in density and form factor at greater depths, while for the low-density, cold surfacenévéin Francefm≈ 2 kHz. and increased with the increase in temperature at greater depths. All Cole-Cole diagrams showed both impurity-ion losses at low frequencies below 6 kHz., and a spreading factor of the distribution in relaxation times caused by the changes in the physical properties of the glacier with depth. Although the method could not measure temperatures absolutely, relative temperature differences and the position of the 0°C. isotherm were detected when a temperature gradient existed in a glacier.

scholarly journals Dielectric Relaxation in Temperate Glaciers

1967 ◽  
Vol 6 (48) ◽  
pp. 897-909
Author(s):  
P. W. F. Gribbon
Keyword(s):  
Dielectric Relaxation ◽  
Loss Factor ◽  
Relaxation Times ◽  
Frequency Range ◽  
Spreading Factor ◽  
Cold Surface ◽  
Relative Temperature ◽  
Low Frequencies ◽  
Glacial Ice ◽  
Impurity Ion

The dielectric relaxation of névé and glacial ice has been studied on two temperate glaciers in Greenland and France. Measurement of the capacitance and loss tangent in the audio-frequency range of thin parallel wires placed on the surface of a glacier gave ϵ′, the relative permittivity, and ϵ″, the loss factor of the névé. The relaxation time can be expressed in terms of the frequency fm at the maximum ϵ″ value of the Cole-Cole ϵ″−ϵ′ diagram, and its variation with depth was derived from the Cole-Cole diagrams obtained for different wire separations.For wet 0°C. surface snow in Greenland, fm ≈ 4 kHz. and decreased with the increase in density and form factor at greater depths, while for the low-density, cold surface névé in France fm ≈ 2 kHz. and increased with the increase in temperature at greater depths. All Cole-Cole diagrams showed both impurity-ion losses at low frequencies below 6 kHz., and a spreading factor of the distribution in relaxation times caused by the changes in the physical properties of the glacier with depth. Although the method could not measure temperatures absolutely, relative temperature differences and the position of the 0°C. isotherm were detected when a temperature gradient existed in a glacier.

Main Dielectric Dispersion Region of Mixtures of some Long-Chain Alcohols with Non-Polar Solvents

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1363-1367 ◽  
Author(s):  
F. F. Hanna ◽  
I. K. Hakim
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Dielectric Dispersion ◽  
Concentrated Solutions ◽  
Polar Solvents ◽  
Dispersion Region ◽  
Long Chain

Abstract The dielectric constant ε' and dielectric loss ε" are measured for concentrated solutions of n-dodecanol and n-octanol with five non-polar solvents at five frequencies between 2 and 400 MHz at three temperatures between 20 and 60 °C. The effective dipole moments have been calculated and found to decrease with increasing dilution. The relaxation times of the concentrated solutions are lower than that of the pure alcohols, decrease with dilution and are dependent on the nature of the non-polar solvents.

Observation of Dielectric Peaks in Glassy Se70Te20Sn10 Alloy

2012 ◽  
Vol 329 ◽  
pp. 165-175 ◽  
Author(s):  
A. Sharma ◽  
N. Mehta
Keyword(s):  
Chalcogenide Glasses ◽  
Relaxation Times ◽  
Dielectric Dispersion ◽  
Dielectric Constants ◽  
Audio Frequency ◽  
Frequency Range ◽  
Glass Transition Region ◽  
Dipolar Relaxation ◽  
The Past ◽  
Frequency Dependences

The Temperature and Frequency Dependences of the Dielectric Constants () and Dielectric Loss (") Were Studied in Glassy Se70Te20Sn10Alloy in the Audio-Frequency Range below the Glass Transition Region. the Results Indicated that Dielectric Dispersion Occurred in Glassy Se70Te20Sn10Alloy. Well-Defined Dielectric Peaks Were Obtained in Glassy Se70Te20Sn10Alloy; these Are Rarely Observed in Chalcogenide Glasses. such Loss Peaks Were Not Observed in the Glassy Se80-xTe20SnxSystem in the past for Sn Concentrations of x ≤ 8. A Detailed Analysis of the Data Showed that the Results Could Be Explained in Terms of Dipolar Relaxation, with a Distribution of Relaxation Times, this Is Quite Expected in the Case of Chalcogenide Glasses.

DIELECTRIC PROPERTIES OF POLYVINYL ACETALS

1952 ◽  
Vol 30 (12) ◽  
pp. 940-947 ◽  
Author(s):  
B. L. Funt ◽  
T. H. Sutherland
Keyword(s):  
Dielectric Properties ◽  
Electrical Properties ◽  
Dielectric Relaxation ◽  
Relaxation Times ◽  
Dielectric Dispersion ◽  
Transition Temperatures ◽  
Free Energies ◽  
Frequency Range ◽  
Physical Picture ◽  
Electrical Relaxation

Measurements of dielectric dispersion in vinyl acetal and formal polymers were performed over the frequency range 0.050 to 100 kc. at temperatures between 25 and 135 °C. The results reflect the effects of internal plasticization on the electrical properties of the polymers. With increasing size of the substituent groups from formal to butyral the dispersion range is shifted to lower temperatures at a given frequency. Electrical relaxation times and transition temperatures were obtained and values of enthalpies, free energies, and entropies of activation were calculated. A tentative physical picture of the mechanism of dielectric relaxation in these polymers was also formulated.

scholarly journals Molecular Interactions and Dielectric Relaxation in the Mixtures of Amines with 2-Fluorobenzoic Acid in 1, 4-Dioxane

2019 ◽  
Vol 9 (1) ◽  
pp. 2866-2870
Keyword(s):  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Relaxation Times ◽  
Angular Frequency ◽  
Dielectric Constants ◽  
Intramolecular Interactions ◽  
Dielectric Parameters ◽  
Molar Ratios ◽  
Group Rotation ◽  
Static Dielectric Constants

For the present study, the estimation of the static dielectric constants (0 ), dielectric constant () at an angular frequency and dielectric loss () of methyl, ethyl and propyl amines with 2-fluorobenzoic acid in 1,4-dioxane were carried using Klystron microwave bench at frequency 9.43GHz. Using the dielectric parameters, the overall relaxation time (1 ) and group rotation relaxation time (2 ) of the polar solute molecules and average relaxation times (0 ) were also determined using Higasi and Gopalakrishna method employing Debye’s equations. The obtained results revealed that, out of five different molar ratios, relaxation time () is maximum at 1:1 molar concentration for all the systems due to inter and intramolecular interactions through hydrogen bonding. In addition, the dipole moment, activation viscous flow (f) and dielectric relaxation (f ) due to molar free energy also been discussed.

Dielectric Relaxation and Intramolecular Rotation in Aliphatic Ketones

1973 ◽  
Vol 51 (16) ◽  
pp. 2671-2675 ◽  
Author(s):  
John Crossley
Keyword(s):  
Dielectric Relaxation ◽  
Relaxation Times ◽  
Dielectric Constants ◽  
Aromatic Ketones ◽  
Paraffin Oil ◽  
Aliphatic Ketones ◽  
Intramolecular Rotation ◽  
Static Dielectric Constants ◽  
Viscosity Dependence

Dielectric constants and losses have been obtained for a number of aliphatic and aromatic ketones in cycloexane, n-hexadecane, decalin and paraffin oil – cyclohexane mixtures at up to ten frequencies between 1 and 145 GHz at 25 °C. Static dielectric constants have also been measured at 2 MHz. The results for each system have been analyzed in terms of a Cole–Cole distribution. The relaxation times and their viscosity dependence are discussed in terms of dipole reorientation by intramolecular and whole molecule rotations.

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