The pressure and temperature dependence of the static permittivity and density of heptanol isomers

Vij, J. K.; Scaife, W Garrett; Calderwood, J.H.

doi:10.1088/0022-3727/11/4/018

Cited by 41 publications

(41 citation statements)

References 12 publications

(13 reference statements)

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“…24 Johari and Dannhauser 5 also found that process II especially at lower temperatures was of the Davidson-Cole type. 25 This work was extended by Vij et al 12,13 to an investigation of four heptanol isomers (1-heptanol, 3-heptanol, 3-methyl-2-hexanol, and 2-methyl-2-hexanol) who investigated these liquids in the frequency range of 20 Hz to 6 MHz and temperatures from 373 K to 243 K. Since their low frequency measurements were limited to 20 Hz only, they did not observe the non-Arrhenius nature of the dominant process at the lowest temperatures. The nature of the dominant process was of the Debye-type in 1-heptanol.…”

Section: Introductionmentioning

confidence: 76%

“…Table IV lists the dielectric relaxation time of the dominant process (process I for the data at P ∼ 0.1 MPa), τ II and the Kirkwood correlation factor, g, at a temperature of 258 K. The calculated values of Kirkwood correlation factor, g, and the relaxation times for a selected set of temperature and pressure are also listed. In order to calculate the g-factor at a pressure of 200 MPa and temperature of 258 K density for 5-methyl-2-hexanol was extrapolated from its close isomer which was already reported by Vij et al 12 From a perusal of Table IV (Table III), it would not therefore be correct to state that τ I is governed by hydrogen bonding alone and τ II corresponding to process II, refers to the dynamics of the alkyl chains and the latter process only contributes to the structural relaxation. Based on these experimental findings, it is reasonable to assert that both processes contribute to the structural relaxation.…”

Section: B Structural Relaxationmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Work at the time was hampered by the long and tedious manual procedures required to make dielectric measurements for different pressures at different temperatures. More recently, however automated data collection techniques as well as the data analysing techniques 14,15 have made such studies more revealing of the effects observed at pressures especially exceeding 500 MPa (5 kbar).…”

Section: Introductionmentioning

confidence: 99%

“…Since hydrogen bonding effects the orientational correlation of dipoles through short-range dipolar interactions given by Onsager-KirkwoodFröhlich theory, 21 it changes the equilibrium dielectric permittivity due to both changes in the density and an alteration in the structure but except for cases where it leads to ring dimer formation. 12,22,23 Pressure in general raises the static dielectric permittivity. 5,12 Pressure has pronounced effects on the dielectric relaxation time especially at lower temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…12,22,23 Pressure in general raises the static dielectric permittivity. 5,12 Pressure has pronounced effects on the dielectric relaxation time especially at lower temperatures. 5,13 For experimental investigations up to 400 MPa (4 kbar) and for frequencies in the range 50 mHz to 0.5 MHz and temperatures down to 215 K, Johari and Dannhauser made for the first time a detailed investigation 5 of five isomeric octanols and found that the predominant dispersion is well described by the Debye equation in only some of these octanols.…”

Section: Introductionmentioning

confidence: 99%

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Effect of high hydrostatic pressure on the dielectric relaxation in a non-crystallizable monohydroxy alcohol in its supercooled liquid and glassy states

Pawlus

Paluch

Nagaraj

et al. 2011

The Journal of Chemical Physics

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The complex relative permittivity of a non-crystallizable secondary alcohol, 5-methyl-2-hexanol, is measured over a wide range of temperatures and pressures up to 1750 MPa (17.5 kbar). The data at atmospheric pressure (P = 0.101 MPa) are analyzed in terms of three processes, and the results are in complete agreement with that of O. E. Kalinovskaya and J. K. Vij [J. Chem. Phys. 112, 3262 (2000)]. Process I is of the Debye type and process II is of the Davidson-Cole type, whereas process III is identified as the Johari-Goldstein relaxation process. For pressures of ∼500 MPa and higher, processes I and II are seen to merge into each other to form a single dominant process which unambiguously cannot be resolved into more than one process. The dielectric relaxation strength of process I decreases slightly initially with pressure and when the two processes have merged at elevated pressures, the total relaxation strength increases with increase in pressure. Process III is better resolvable at higher pressures especially above T g in the supercooled liquid state for the reason that the separation in the time scales between the dominant and the JG relaxation process increases at elevated pressures. Surprisingly we find a change in the slope in the plot of log τ JG vs. 1/T for P = 1750 MPa. The results for the relaxation time of alcohols are compared with the Kirkwood correlation factor, g, and it is found that higher is the g, lower is the relaxation time for process I, and it is more of the Debye type. On a reduction in g brought about by an increase in pressure at lower temperatures, the dominant process becomes non-Debye though extensive hydrogen bonding is still present. The dielectric strength of the merged processes increases with increase in pressure. The values of the steepness index, m = |d log τ /d(T g /T)| T = Tg for processes I and II are different for P = 0.1 MPa. However the value of m, for the composite process, which is a merger of processes I and II, for P = 1750 MPa is almost the same for process II at P = 0.1 MPa. From the results of the activation volume, activation enthalpy, and a comparison of the relaxation times with the g factor, we conclude that both processes I and II are significantly affected by hydrogen bonding and both contribute to the structural relaxation.

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Section: Introductionmentioning

confidence: 76%

Section: B Structural Relaxationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effect of high hydrostatic pressure on the dielectric relaxation in a non-crystallizable monohydroxy alcohol in its supercooled liquid and glassy states

Pawlus

Paluch

Nagaraj

et al. 2011

The Journal of Chemical Physics

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Messungen dielektrischer Eigenschaften bei hohen Drücken und tiefen Temperaturen III: Die statische und komplexe Dielektrizitätszahl von Cyclopentanol

Würflinger

1982

Ber Bunsenges Phys Chem

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The static permittivity ε of liquid and solid cyclopentanol has been determined as a function of temperature (+ 50 to ‐ 80 °C) and pressure (up to 3 kbar). From these and PVT data the Kirkwood correlation factor g has been calculated. Plots of g as a function of temperature intersect at g = 2.6 and at the “cross‐over‐temperature” of 30 °C. The calculations have also been extended to the plastic phases (SI, SII) of cyclopentanol, because their permittivity (especially that for SII) exceeds that for the liquid considerably. There is a drastic decrease of ε to values about 2.5 at a lower SII/SIII transition. The increase of ε at the freezing point is larger as should be expected according to the Onsager equation. The temperature dependence of g at constant volume is negative. Also the dielectric relaxation has been studied for the plastic phases of cyclopentanol up to frequencies of 10 MHz. The complex permittivity has been evaluated with the help of the Cole‐Cole equation, showing only a small deviation from a simple Debye‐mechanism (α ≤ 0.05). The relaxation times τ about 1000 bar vary from 10−5 s (‐70°C) to 3 · 10−8 s (‐ 10°C) in solid cyclopentanol, τ being discontinuous at the SI/SII transition. Activation volumes (5–7 cm3 mol−1) and activation energies (40 kJ mol−1) have been derived from the pressure and temperature dependence if τ.

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Dielectric constants, refractive indexes and polarizations for 1‐Alcohol +Heptane mixtures at 298.15 and 308.15 K

Sastry

Valand

1997

Ber Bunsenges Phys Chem

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New experimental data on dielectric constants, refractive indexes for the binary mixtures of heptane + 1‐pentanol, + 1‐hexanol, + 1‐heptanol, + 1‐octanol, 1‐decanol and + 1‐dodecanol at 298.15 and 308.15 K are reported. The molar and orientation polarizations were calculated for the pure and mixture components. The excess dielectric functions were estimated. The variation of correlation factor and free energy of mixing has been examined over the whole range of 1‐alcohol mole fractions for all the binary mixtures. The results are interpreted in terms of molecular interactions.

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The pressure and temperature dependence of the static permittivity and density of heptanol isomers

Cited by 41 publications

References 12 publications

Effect of high hydrostatic pressure on the dielectric relaxation in a non-crystallizable monohydroxy alcohol in its supercooled liquid and glassy states

Effect of high hydrostatic pressure on the dielectric relaxation in a non-crystallizable monohydroxy alcohol in its supercooled liquid and glassy states

Messungen dielektrischer Eigenschaften bei hohen Drücken und tiefen Temperaturen III: Die statische und komplexe Dielektrizitätszahl von Cyclopentanol

Dielectric constants, refractive indexes and polarizations for 1‐Alcohol +Heptane mixtures at 298.15 and 308.15 K

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