Dielectric relaxation of some aliphatic ester molecules in solutions

1979 ◽  
Vol 57 (7) ◽  
pp. 1035-1038 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Relaxation Times ◽  
Activation Parameters ◽  
Dielectric Absorption ◽  
Aliphatic Ketones ◽  
Dielectric Data ◽  
Aliphatic Ester ◽  
Aliphatic Esters ◽  
Intramolecular Rotation

The dielectric absorption of several aliphatic esters has been examined in the microwave region over a range of temperatures in n-heptane, cyclohexane, and benzene. The relaxation times and the thermodynamic parameters have been determined using the measured dielectric data. The values of the relaxation time for those solutions for which there are available known data agree well with other determinations. The relaxation times and the various molar activation parameters have been discussed in terms of dipole reorientation by molecular and intramolecular rotation. It would appear that the relaxation behavior of aliphatic esters is similar to that for other aliphatic molecules, such as aliphatic ketones studied previously.

Relaxation processes of some simple aliphatic molecules in dilute solutions

1977 ◽  
Vol 55 (4) ◽  
pp. 297-301 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Carbon Tetrachloride ◽  
Dielectric Relaxation ◽  
Thermodynamic Parameters ◽  
Relaxation Times ◽  
Relaxation Processes ◽  
Dilute Solutions ◽  
Microwave Region ◽  
Nonpolar Solvents ◽  
Dielectric Data ◽  
Intramolecular Rotation

The dielectric relaxation processes of acetone, cyclohexanone, 4-methyl-2-pentanone, and 4-heptanone in dilute nonpolar solvents, n-heptane, cyclohexane, benzene, and carbon tetrachloride have been studied in the microwave region over a temperature range 10 to 60 °C. The relaxation times and the thermodynamic parameters for the activated states have been determined using the measured dielectric data. The results have been discussed in terms of dipole reorientation by molecular and intramolecular rotation and compared, wherever possible, with other similar studies on aliphatic molecules.

Microwave Absorption and Relaxation Behavior of Some Simple Ketones in Dilute Solutions

1975 ◽  
Vol 53 (1) ◽  
pp. 23-28 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Relaxation Time ◽  
Thermodynamic Parameters ◽  
Microwave Absorption ◽  
Reasonable Agreement ◽  
Relaxation Times ◽  
Relaxation Behavior ◽  
The Other ◽  
Dielectric Absorption ◽  
Dielectric Data ◽  
Thermodynamic Processes

The dielectric absorption of solutions of 2-hexanone, 4- and 5-nonanone, and 2-decanone has been examined in the microwave region over a range of temperatures in n-heptane, cyclohexane, and benzene. The relaxation times and the thermodynamic parameters for the activated states have been determined using the measured dielectric data. The values of relaxation time are in reasonable agreement at the temperature at which there are available known data. Both the relaxation behavior and the thermodynamic processes are discussed and, where possible, compared with corresponding results of the other workers.

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.

Dielectric relaxation studies. III. Allyl bromide and allyl ethers in liquid state

1981 ◽  
Vol 59 (11) ◽  
pp. 1690-1695
Author(s):  
M. Jeyaraj ◽  
J. Sobhanadri
Keyword(s):  
Dielectric Relaxation ◽  
Allyl Bromide ◽  
Relaxation Times ◽  
Activation Parameters ◽  
Relaxation Mechanism ◽  
Microwave Frequencies ◽  
Allyl Ethers ◽  
Dielectric Data ◽  
Permittivity Measurements ◽  
Allyl Compounds

Complex dielectric permittivity measurements are reported at radio and microwave frequencies for four allyl compounds in the temperature range 30–70 °C. The analysis of dielectric data in terms of Cole–Cole arc, multiple relaxation times, and Higasi's distribution function reveals that the overall molecular rotation is the dominant relaxation mechanism in these unsaturated compounds. The activation parameters are evaluated assuming dielectric relaxation to be a rate process.

Relaxation processes of quinoline, isoquinoline, and their mixtures

1980 ◽  
Vol 58 (1) ◽  
pp. 20-24 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Thermodynamic Parameters ◽  
Molecular Motion ◽  
Polar Solvent ◽  
Relaxation Times ◽  
Relaxation Processes ◽  
Polar Components ◽  
Dielectric Absorption ◽  
System A ◽  
Dielectric Data ◽  
Activated State

The dielectric absorption of quinoline, isoquinoline, and their binary mixtures has been studied in the microwave region over a range of temperatures in dilute benzene and n-heptane solutions. The relaxation times and the thermodynamic parameters for the activated state have been determined using the measured dielectric data. The results obtained have been discussed in terms of the molecular motion of the system. A relation has been proposed to represent the relaxation behavior of a system of two Debye-type polar components in a non-polar solvent. The relation has been tested by comparing the calculated values with those determined experimentally for a few systems consisting of similar, simple rigid polar molecules.

Dielectric relaxation of some aliphatic ketones in dilute solutions

1976 ◽  
Vol 54 (7) ◽  
pp. 794-799 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Free Energy ◽  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Relaxation Mechanism ◽  
Relaxation Data ◽  
Nonpolar Solvents ◽  
Aliphatic Ketones ◽  
Entropy Of Activation ◽  
Enthalpy And Entropy ◽  
Dielectric Relaxation Behavior

The dielectric relaxation behavior of 2-butanone, 2-pentanone, 2-heptanone, and 3-nonanone in dilute nonpolar solvents, n-heptane, cyclohexane, benzene, and carbon tetrachloride has been studied in the microwave region at a number of temperatures. The relaxation data have been used to estimate the free energy, enthalpy, and entropy of activation for the relaxation mechanism. The values of the relaxation time for those solutions for which there are available known data agree well with other determinations. The results have been discussed in terms of dipole reorientation by intramolecular and overall molecular rotation and compared, wherever possible, with other similar studies on aliphatic molecules.

Dielectric Studies. Part XXXI. Analysis of the Dielectric Data of Phenol and its Polymerized Forms

1971 ◽  
Vol 49 (7) ◽  
pp. 1106-1114 ◽  
Author(s):  
M. D. Magee ◽  
S. Walker
Keyword(s):  
Dipole Moment ◽  
Relaxation Time ◽  
Mole Fraction ◽  
The State ◽  
Distribution Parameter ◽  
Dielectric Studies ◽  
Microwave Frequencies ◽  
Dielectric Absorption ◽  
Dielectric Data ◽  
Intramolecular Process

The dielectric absorption and dispersions of several solutions of phenol in p-xylene have been measured at four microwave frequencies and at 2 MHz at a temperature of 25 °C. The data have been analyzed in terms of a mean relaxation time, a distribution parameter, and an apparent dipole moment which are useful empirical parameters for assessing the state of aggregation of the phenol molecules. The relaxation time at the lowest practicable concentration (0.02 mole fraction) is long for a molecule expected to relax predominantly by an intramolecular process. This and the behavior of the relaxation time and apparent dipole moment with increasing concentration are considered in terms of a model based on progressive association into an extended series of multimers, the trimer having a zero (or low) dipole moment and higher multimers becoming increasingly flexible.

The dielectric behaviour of dipolar mixtures I: chlorobenzene–nitrobenzene mixtures

1986 ◽  
Vol 64 (11) ◽  
pp. 1534-1536 ◽  
Author(s):  
F. F. Hanna ◽  
K. N. Abdel-Nour ◽  
A. M. Ghoneim
Keyword(s):  
Relaxation Time ◽  
Thermodynamic Parameters ◽  
Relaxation Times ◽  
Dielectric Behaviour ◽  
Dilute Solutions ◽  
Single Relaxation Time ◽  
Microwave Region ◽  
Dielectric Absorption

The dielectric absorption of dilute solutions of nitrobenzene, chlorobenzene, and their mixtures in cyclohexane and Decalin® have been measured in the microwave region at three temperatures between 20 and 40 °C. The relaxation times and thermodynamic parameters are determined. A single relaxation time is found for the mixtures, and the results are discussed.

Dielectric relaxation of nitromethane, some nitriles, and their mixtures in dilute solutions

1987 ◽  
Vol 65 (12) ◽  
pp. 1573-1576 ◽  
Author(s):  
M. P. Madan
Keyword(s):  
Refractive Index ◽  
Dielectric Relaxation ◽  
Thermodynamic Parameters ◽  
Molecular Motion ◽  
Empirical Relation ◽  
Relaxation Times ◽  
Relaxation Behaviour ◽  
Polar Components ◽  
Dielectric Absorption ◽  
Activated State

The dielectric absorption of nitromethane, benzonitrile, and acetonitrile and their binary mixtures has been studied in the microwave region over a range of temperatures in dilute benzene solutions. The data on static and optical permittivities at 20 °C have also been obtained, from measurements at 100 kHz and from measuring the refractive index for sodium-D lines, for a few cases. These data have been used to determine the relaxation times and the thermodynamic parameters for the activated state. The results obtained have been discussed in terms of the molecular motion of the systems. A new empirical relation has been proposed to represent the relaxation behaviour of a system of two Debye-type polar components in a nonpolar solvent. The relation has been tested, along with a previously suggested relation, by comparing the calculated values with those determined experimentally.

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