Compressed-liquid dielectric constants and derived excess volumes for simple liquid mixtures: N 2 + CH 4 and Ar + CH 4

Abstract

Liquid mixture excess volumes have been determined at 100 to 115 K with pressures up to 20 MPa for nitrogen + methane and argon + methane at five compositions each. The method involved measurement of pure-component and mixture dielectric constants which were combined with previously published pure-component molar volumes. Excess volumes were derived on the assumption of zero excess in the Clausius-Mossotti function. Discrepancies between the present V E results and previously reported values based on volumetric measurements are probably within the uncertainties of the previous studies. Excess isothermal compressibilities can be readily derived from the results. Values of this excess property were shown to be a major contribution to the isothermal compressibility of nitrogen + methane at lower pressures.