Determination of the Relative Permittivity, ϵ′, of Methylbenzene at Temperatures between (290 and 406) K and Pressures below 20 MPa with a Radio Frequency Re-Entrant Cavity and Evaluation of a MEMS Capacitor for the Measurement of ϵ′

Abstract

The relative electric permittivity of liquid methylbenzene has been determined with an uncertainty of 0.01 % from measurements of the resonance frequency of the lowest order inductive-capacitance mode of a re-entrant cavity (J. Chem. Thermodyn. 2005, 37, 684–691) at temperatures between (290 and 406) K and pressures below 20 MPa and at T = 297 K with a MicroElectricalMechanical System (MEMS) interdigitated comb capacitor. For the re-entrant cavity, the working equations were a combination of the expressions reported by Hamelin et al. (Rev. Sci. Instrum. 1998, 69, 255−260) and a function to account for dilation of the resonator vessel walls with pressure that was determined by calibration with methane (J. Chem. Eng. Data 2007, 52, 1660–1671). The results were represented by an empirical equation reported by Owen and Brinkley (Liq. Phys. Rev. 1943, 64, 32–36) analogous to the Tait equation (Br. J. Appl. Phys. 1967, 18, 965–977) with a standard (k = 1) uncertainty of 0.33 %. The values reported by Mospik (J....