Measurement of static dielectric constants of supercritical fluid solvents and cosolvents: Carbon dioxide and argon, carbon dioxide, and methanol at 323 K and pressures to 25 MPa
β Scribed by Bruce D. Drake; Richard L. Smith Jr.
- Publisher
- Elsevier Science
- Year
- 1990
- Tongue
- English
- Weight
- 682 KB
- Volume
- 3
- Category
- Article
- ISSN
- 0896-8446
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β¦ Synopsis
A new apparatus for the measurement of dielectric constants of high pressure gases has been constructed. The apparatus consists of a recirculating visual flow cell and a concentric cylinder dielectric constant flow cell. Measurement of the dielectric constant is made by a unique counter-oscillator circuit, in which the capacitance is determined by relaxation of a unijunction transistor oscillator circuit and counted by a crystal oscillator.
Dielectric constants are reported for supercritical mixtures of carbon dioxide + argon and carbon dioxide + methanol at a temperature of 322.9 K and pressures to 25 MPa. The dielectric constant shows a sharp increase near the critical pressure.
Dielectric constants were linear with densities calculated by the Suzuki equation-of-state. The dielectric cdnstant for the methanol-carbon dioxide system was found to be less than a mole fraction average of the pure component dielectric constants.
π SIMILAR VOLUMES
The excess molar enthalpies H E m of five binary mixtures: (carbon dioxide + methanol, or ethanol, or N-methyl-2-pyrrolidone, or methyl cyanoacetate, or N-formyl morpholine), and one ternary mixture: [xCO2 + (1x){0.8085(CH2)4SO2 + 0.1915H2O}] were measured at the temperature T = 298.15 K and pressur
A new isothermal flow calorimeter for gases at high temperatures and pressures is described. The calorimeter employs a throttling-capillary tube to provide both the pressure drop and the heating element. Considerable care was taken to operate the calorimeter in an isothermal environment by use of a