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The Dielectric Permittivity of Saturated Liquid Carbon Dioxide and Propane Measured Using Cross Capacitors



E May, Michael R. Moldover, James W. Schmidt


The relative dielectric permittivities er of saturated liquid carbon dioxide (CO2) and propane (C3H8) were measured using well-characterized cross capacitors in the range 260 K < T < 300 K. We calculated the molar polarizability sat (er -1)/[(er + 2)rsat] of CO2 using the equation of state of Span and Wagner to convert our values of the saturation vapor pressure psat to values of the saturated liquid density rsat. In the range 260 K < T < 300 K, we find sat = 7.659 with bounds of 0.001 cm3 mol 1. The systematic difference between measurements made with two different capacitors was 0.001 cm3 mol 1; this difference is equivalent to a shift of 12 mK in the liquid temperature. The uncertainty of sat from the equation of state of CO2 is approximately 0.002 cm3 mol 1. Our values of sat for CO2 are consistent with the results of Moriyoshi et al and of May et al; however, our values are 0.5 % larger than the values determined by Haynes. For saturated liquid propane, our values of er differ from the values of Haynes and Younglove, by 0.0004 or less, which is nearly within their stated uncertainty of 0.0002.
International Journal of Thermophysics
No. 3


carbon dioxide, cross capacitors, dielectric constant, permittivity, polarizabilith, propane, saturated liquid


May, E. , Moldover, M. and Schmidt, J. (2005), The Dielectric Permittivity of Saturated Liquid Carbon Dioxide and Propane Measured Using Cross Capacitors, International Journal of Thermophysics (Accessed March 1, 2024)
Created April 30, 2005, Updated October 12, 2021