Dielectric Constant of Mixtures of Carbon Dioxide and n-Dodecane Between 283 K and 343 K

Abstract

The dielectric constant (relative permittivity) of mixtures of carbon dioxide (CO2) and n-dodecane (n-C12H26) was experimentally determined for temperatures between 283 K and 343 K in a purpose-built apparatus which enabled simultaneous measurements of relative permittivity and liquid-phase mass density. A flat response of the dielectric constant with respect to frequency was observed between 1 kHz and 400 kHz. The mixture dielectric constant was found to be inversely proportional to the temperature and to the CO2 concentration in the liquid mixture. The departure from the relative permittivity ideal mixture behavior (calculated using the classical Bottcher mixing rule) was correlated via a first-order Redlich-Kister volume fraction expansion with a temperature dependent parameter. The RMS deviation of this method was 0.37 %. The liquid-phase mass density was predicted by the PCP-SAFT equation of state with a RMS deviation of 0.26 %.