Study On Solubility Of Pure Or Mixed Solid In Supercritical CO₂

Supercritical fluid extraction (SFE) is a novel separation technology developed on the basis of the characteristics of supercritical fluid, and the research carried on it is with huge practical meanings. The addition of suitable cosolvent will sharply increase the solubility of solute, and this will also increase the possibility of the industrialization of SFE technology.The study on the SFE with cosolvents is still far from meeting the requirement of the theoretical development, and the solubility data of SFE with cosolvents still need to be enriched and perfect. Most of the solubility measurements are concerning the single solute in supercritical binary systems, but the complex multi-system is the most familiar in practical applications. Nowadays, the research on the solubility of multi-component in supercritical fluid is scarce, so the study on the solubility of multi-component in supercritical fluid and the interaction among molecules will be theoretical significance, and this is still directive to increase the gained rate and selectivity of target solute in SFE process. Solubilities of pure and mixed solutes in supercritical CO₂ with and without cosolvent were measured in this work. The experimental solutes include: p-aminobenzoic acid, 5-sulfosalicylic acid and o-phthalic acid, and the selected cosolvent are acetone, ethanol, tributyl phosphate, cyclohexane and ethyl acetate at the molar fraction ranging from 0.02 to 0.053. The experimental temperature and pressure increase from 8.0 to 21.0 MPa and from 308.15 to 328.15 K, respectively, and the effects of temperature, pressure and cosolvent concentration on the solubility of solutes are studied in this work.Relative to the extensive study on the solubility measurements in supercritical fluid, the study of this field (especially in the situation with cosolvents) is still insufficient in our country. The researched solutes in this work are firstly studied all over the world, so this work is creative in some sense, and the measured data can enrich the basic data of reference.