The Dielectric Constant and Density of Benzene to 400 °C and 3000 bar

Abstract

A high pressure apparatus is described to measure simultaneously within one cell the dielectric constant and the density of non‐polar supercritical fluids to 400 °C and 3000 bar. Thus relations between the dielectric constant and the fluid density at any given temperature can be discussed with particular reliability. The apparatus consists of a cylindrical autoclave, which encloses a stainless steel belows containing the sample. A cylindrical capacitor (ca. 60 pF) is mounted inside the bellows. A back‐up fluid of heptane is used to produce the pressure on the bellows. Measurements are made between 10 kHz and 1 MHz. Values of the dielectric constant ϵ are reported for 10 temperatures between 27.5 and 400 °C and for pressures between 1 bar and 3000 bar. At 27.5°C and 1 bar ϵ is 2.273. At 100°C it varies from 2.124 to 2.425 between 1 and 2800 bar. At 400°C and 3000 bar ϵ = 2.198. The probable error is below 0.2%. Density measurements cover the same range. The temperature dependence of ϵ at constant density is very small. The Clausius‐Mossotti‐function is presented for the whole region. In accordance with existing theories it can be described as a three‐term series in powers of density and a T−1‐term.

Electron thermalization distances and free-ion yields in dense gaseous and liquid benzene

“…19. The most recent works concentrated on measurements at constant temperature and increasing density (17,18). The most extensive earlier measurements in the liquid along the coexistence curve reported permittivities up to 473 K (15).…”

Infrared study of water–benzene mixtures at high temperatures and pressures in the two- and one-phase regions

“…The average isothermal compressibility of benzene in the 100-200 bar at 473 and 523 K are estimated as 3.5ϫ10 Ϫ4 and 6.2 ϫ10 Ϫ4 bar Ϫ1 , respectively, from literature data. 35 These values are distinctly larger than the corresponding values of water, 8.2ϫ10 Ϫ5 and 1.3ϫ10 Ϫ4 bar Ϫ1 . 34 Therefore, the increasing rate of ͉E a ͉ with pressure will be larger in benzene than in water and therefore, (‫⌬ץ‬E a /‫ץ‬p) T Ͻ0.…”

“…The thermal expansivity of water and benzene at high temperatures and pressures can be roughly estimated from literature data. 34,35 In the 473-523 K range, the average expansivities of benzene at 100 and 200 bar are estimated to be 2.2ϫ10 Ϫ3 and 1.6ϫ10 Ϫ3 , respectively, and larger than those of water, 1.6ϫ10 Ϫ3 and 1.5 ϫ10 Ϫ3 . Since E a is negative in nature, these data suggest (‫⌬ץ‬E a /‫ץ‬T) p Ͼ0.…”

Computational Study of Excess Electron Mobility in High-Pressure Liquid Benzene

“…Equation is slightly modified from the Tait equation used by Gibson and Kincaid to cover the range up to 3000 bar and 470 K. The details are described in the Supporting Information. Table shows the relation between experimental values, − including those interpolated using eq , and the computed values of the density of liquid benzene. As shown in Table , the OPLS-AA values and GAFF values shows good agreement with the experimental values over a wide range of pressures and temperatures.…”