Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

To understand the phase behavior of 3-hydroxybenzaldehyde (3-HBA) and the solubility effect of 3-HBA and its isomer 4-hydroxybenzaldehyde (4-HBA) on each other in supercritical carbon dioxide (SCCO2), the equilibrium solubility of 3-HBA and its mixture with 4-HBA, was measured in SCCO2 binary system (one solute + SCCO2) and ternary system (two solutes + SCCO2) at temperature from (308 to 328) K and pressure from (11.0 to 21.0) MPa. Comparing the solubility of 3-HBA and 4-HBA between in the binary system and ternary system, it was found that the equilibrium solubility of 3-HBA and 4-HBA was both enhanced in the ternary system due to the molecular interaction. The solubility of 3-HBA and 4-HBA in the ternary system was correlated by Chrastil, Mendez-Santiago and Teja (M-S-T), Sovova, their modified models, and Zhu et al. model. In addition, a new model was deduced and established based on the Chemistry Association Theory and verified by 636 groups of solubility data, and the correlated results indicated that the new model obtained a less deviation than other models, including the modified Chrastil model, the modified M-S-T model, the modified Sovova model, and Zhu et al. model, all of which have four adjustable parameters.