Dielectric Relaxation of Bromoalkanes in Cyclohexane Solution

1972 ◽  
Vol 50 (13) ◽  
pp. 2031-2034 ◽  
Author(s):  
Sing Pin Tay ◽  
John Crossley
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Dielectric Constant And Loss ◽  
Distribution Parameters

Mean relaxation times, Cole–Cole distribution parameters and apparent dipole moments, obtained from dielectric constant and loss measurements at 2 MHz and 1.5, 2.0, 2.5, 9.3, 16, 24, 35, 70, and 145 GHz, are reported for 1-, 2-, and 4-bromooctane, 1-bromodecane, 1-bromododecane, 1-bromohexadecane, 1-bromooctadecane, and 1,10-dibromodecane in cyclohexane solution at 25 °C.

The dielectric relaxation of some diols in p-dioxane solution

1978 ◽  
Vol 56 (3) ◽  
pp. 352-354 ◽  
Author(s):  
J. Crossley
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
Relaxation Process ◽  
Alkyl Group ◽  
Relaxation Times ◽  
Dielectric Dispersion ◽  
Dioxane Solution ◽  
Microwave Frequencies ◽  
Dielectric Absorption ◽  
Dielectric Constant And Loss

Dielectric constant and loss data at up to nine microwave frequencies have been obtained for 1-butanol, 1,4-butanediol, 1,7-heptanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-do-decanediol at 25 °C, and for 1,6-hexanediol at 15, 25, 40, and 55 °C, in p-dioxane. In each case the dielectric dispersion is adequately described by a Cole-Cole distribution. The relaxation times for the diols are almost independent of the length of the alkyl group. An intramolecular relaxation process appears to be primarily responsible for the dielectric absorption.

Dielectric relaxation of acetyl- and benzoyl-acetones

1989 ◽  
Vol 67 (5) ◽  
pp. 804-808 ◽  
Author(s):  
R. K. Khanna ◽  
Abha Bhatnagar
Keyword(s):  
Dielectric Relaxation ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Weight Fraction ◽  
Relaxation Mechanism ◽  
Relaxation Processes ◽  
Dielectric Absorption ◽  
Molar Polarization ◽  
Distribution Parameters ◽  
Few Data

Dielectric absorption measurements are reported at radio and microwave frequencies (at six different wavelengths) for acetylacetone and benzoylacetone solutions in benzene, in a temperature range 25–60 °C. Analysis of dielectric data in terms of Cole–Cole arc plots and multiple relaxation processes reveals that, at higher temperatures, overall molecular relaxation is the dominant relaxation mechanism in these β-diketones. The observed relaxation times, distribution parameters, and dipole moments are in reasonable agreement with the few data reported for some temperatures, in the literature. The activation energy parameters are also evaluated assuming dielectric relaxation to be a rate process. Molar polarization vs. weight fraction (concentration) plots show anomalous behaviour for acetylacetone. Keywords: dielectric properties, dielectric losses, relaxation times, dipole moment, dielectric absorption and dispersion, microwave measurements.

A Cavity Perturbation Technique for Measuring Complex Dielectric Permittivities of Liquids at Microwave Frequencies

1974 ◽  
Vol 52 (23) ◽  
pp. 2365-2369 ◽  
Author(s):  
Abhai Mansingh ◽  
D. B. McLay ◽  
K. O. Lim
Keyword(s):  
Dielectric Constant ◽  
Benzene Solution ◽  
Dipole Moments ◽  
Perturbation Technique ◽  
Relaxation Times ◽  
Microwave Frequencies ◽  
Dielectric Constant And Loss ◽  
End Caps ◽  
Good Agreement

A microwave technique for measuring the complex dielectric permittivity of liquids by using a cylindrical cavity oscillating in the TM010 mode is described. The liquid is placed in a cylindrical teflon cell and the dielectric constant and loss of the liquid are evaluated by measuring accurately the changes in the resonant frequency and Q of the cavity for the composite sample and for the teflon alone. This technique has been used to measure the dielectric constant and loss at 2.4 GHz of some pure liquids and solutions in benzene of ortho and meta isomers of difluoro-, dichloro-, dibromo-, and diiodo-benzene. The measured values for the pure liquids are in good agreement with the literature values. The dielectric relaxation times and dipole moments of the dihalobenzenes in benzene solution evaluated by assuming a simple Debye type dispersion show good agreement with the earlier calculated values derived from Cole–Cole plots based on measurements at several microwave frequencies. This technique, by virtue of the use of a teflon cell and of gold plated end caps, allows the determination of the dielectric properties of corrosive liquids at microwave frequencies and another advantage is that very small liquid samples are required.

Dielectric loss measurements for Bis(pentane-2,4-dionato)oxovanadium(IV) in benzene and dioxan

1975 ◽  
Vol 28 (5) ◽  
pp. 1137 ◽  
Author(s):  
MJ Aroney ◽  
RL Angel
Keyword(s):  
Dielectric Loss ◽  
Complex Formation ◽  
Dielectric Relaxation ◽  
Dipole Moments ◽  
Relaxation Times

Dipole moments and dielectric relaxation times determined by dielectric loss measurements are reported for bis(pentane-2,4- dionato)oxovanadium(IV) as a solute in benzene and in dioxan. Evidence is presented for VO(acac)2,dioxan complex formation.

Dielectric studies. Part XX. Molecular relaxation of some heterocyclic amines in dilute solution

1968 ◽  
Vol 46 (14) ◽  
pp. 2369-2372 ◽  
Author(s):  
J. Crossley ◽  
S. Walker
Keyword(s):  
Relaxation Time ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Lone Pair ◽  
Intermolecular Forces ◽  
Dilute Solution ◽  
Microwave Frequencies ◽  
Heterocyclic Molecules ◽  
Dielectric Constant And Loss ◽  
The Difference

Dielectric constant and loss data have been obtained at microwave frequencies for acridine, 4-methyl-pyridine, phthalazine, quinoline, and isoquinoline in both cyclohexane and p-xylene solution. The data have been used to calculate relaxation times and apparent dipole moments. For phthalazine, quinoline, and isoquinoline in cyclohexane at 50 °C the distribution coefficient is zero and their relaxation times are very similar. Although the axes about which these three molecules may relax lead to different volumes being swept out, no variation in relaxation behavior has been detected, and each system can be characterized by one relaxation time. The relaxation times for all the heterocyclic molecules except quinoline and acridine in p-xylene are appreciably longer than in cyclohexane. Relaxation time values appear a sensitive means of detecting the weak molecular interaction between the amine and the p-xylene. The difference in behavior between the quinoline and acridine as opposed to isoquinoline could be attributed to a more appreciable steric effect in the former two, hindering the approach of the π-electrons of the p-xylene molecules to the hybridized lone pair on the nitrogen atom. No interaction is, in fact, detectable in the case of quinoline and acridine. The importance of allowing for weak intermolecular forces, even in dilute solution, when relaxation values are being anticipated, is emphasized.

ChemInform Abstract: APPARENT DIPOLE MOMENTS AND DIELECTRIC RELAXATION TIMES OF 1,4-BENZOQUINONE AND ITS DERIVATIVES IN SOLUTIONS

1975 ◽  
Vol 6 (8) ◽  
pp. no-no
Author(s):  
TOHRU NAGAI ◽  
HIROAKI TAKAHASHI ◽  
KENITI HIGASI ◽  
LESLIE E. SUTTON ◽  
DAVID WADDINGTON
Keyword(s):  
Dielectric Relaxation ◽  
Dipole Moments ◽  
Relaxation Times

scholarly journals Dielectric Relaxation of Mixtures of N-Methylacetamide and N,N-Dimethylformamide Solved in Benzene Using Microwave Absorption Data

2006 ◽  
Vol 61 (3-4) ◽  
pp. 197-204
Author(s):  
Raman Kumar ◽  
V. S. Rangra ◽  
D. R. Sharma ◽  
N. Thakur ◽  
N. S. Negi
Keyword(s):  
Dielectric Relaxation ◽  
Viscous Flow ◽  
Relaxation Process ◽  
Dipole Moments ◽  
Relaxation Times ◽  
Single Frequency ◽  
Absorption Data ◽  
Dielectric Relaxation Process ◽  
Energy Parameters ◽  
Microwave Techniques

The dielectric relaxation times τ and dipole moments μ of N-methylacetamide (NMA) mixed with N,N-dimethylformamide (DMF) in benzene solutions have been obtained using standard standing wave microwave techniques and Gopala Krishna’s single frequency (9.90 GHz) concentration variational method at 25, 30, 35, and 40 ◦C. The energy parameters (ΔHε , ΔFε , ΔSε ) for the dielectric relaxation process of mixtures with equal amounts of NMA and DMF have been calculated and compared with the corresponding energy parameters (ΔHη , ΔFη , ΔSη ) for the viscous flow. On the basis of the observations it is found that the dielectric relaxation process can be treated as a rate process like the viscous flow. Solute-solute and solute-solvent types of the molecular associations have been predicted

Sign in / Sign up

Export Citation Format

Share Document