High-Pressure Bubble- and Dew-Point Data for Systems Containing CO ₂ + (C ₈ /C ₁₀ 1-Alcohol + C ₈ /C ₁₀ /C ₁₂ <i>n</i> -Carboxylic Acid) Systems

Six new high-pressure bubble-and dew-point data sets have been experimentally measured for ternary systems containing carbon dioxide (the solvent), C8 or C10 1-alcohols, and C8 or C10 or C12 n-carboxylic acids (the solutes). These data were measured at a fixed reduced solute mass fraction of 0.5000 between a total solute fraction of 0.020 to 0.640 at temperatures between 308.15 and 358.15 K. These systems displayed complex solute + solute interactions due to the capacity of the solutes to both self- and cross-associate, leading to competing interactions within the mixture. The mixtures displayed both reduced mixture solubility (mostly at higher temperatures) and enhanced mixture solubility (mostly at lower temperatures) indicating that both association and solvation interactions occur within these systems and that the interactions are temperature dependent. The CO2 + 1-octanol + n-decanoic acid and CO2 + 1-decanol + n-dodecanoic acid systems were identified as island systems, indicating that the unlike or solvation interactions are favored in these systems. The RK-Aspen model is shown to provide an adequate description of the phase behavior data including only solute + solvent binary interaction parameters, although the description is poorer at lower temperatures and in the mixture critical region.