MULTIPHASE EQUILIBRIUM BEHAVIOR OF A MIXTURE OF CARBON-DIOXIDE, 1-DECANOL, AND N-TETRADECANE

The liquid-liquid-vapor (llg) phase equilibrium behavior of the mixture CO2 + 1-decanol + n-tetradecane was experimentally studied using a visual cell (stoichiometric) technique with pressure discrimination of +/- 0.01 bar, achieved by coupling a dead weight gauge to the cell pressure transducer. The portion of the three-phase surface of the ternary system examined is bounded by the llg loci of the binary mixtures CO2 + 1-decanol and CO2 + n-tetradecane and from above by an upper critical end point (1-1=g) locus. Phase compositions and solar volumes are reported for the two liquid phases along the 298.15 K isotherm. This three-phase 11g surface is unusual in that it has a two-phase (1g) ''hole'' in it which is completely bounded by 1=1-g critical end points. A rationale for the occurrence of this hole in the llg surface is offered.