Excess volumes of liquid mixtures at high pressures V. Results for [formula omitted] and [formula omitted] up to 200 MPa. Pressure dependence of excess molar Gibbs energies

Abstract

Excess molar volumes V m E of “(triethylamine or acetone or diethylether) + trichloromethane’ and of “(triethylamine or diethylamine) + methanol’ were measured at 298.15 K as a function of mole fraction x and pressure p between 10 MPa and a maximum pressure of 200 MPa; (triethylamine + trichloromethane) was also studied at 308.15 K. The V m E values were determined dilatometrically as the change of volume on mixing the pure components under pressure in a special high-pressure mixing cell mounted in an autoclave. For (acetone + trichloromethane) S-shaped V m E( x) curves at given T and p were found whereas all other mixtures exhibited negative values, that decrease in absolute value with increasing pressure, over the whole mole-fraction range. For the correlation of the V m E( p) curves for given T and p a Simon-type equation was used and the V m E( x) curves were fitted to an equation. From the V m E s obtained, the changes ΔG m E of the excess molar Gibbs energy with pressure were calculated, e.g. G m E decreases by about 310 J·mol −1 between 0.1 and 200 MPa for “0.5(C 2H 5) 3N + 0.5CH 3OH’.