Study On The Solibity Of Solid In Supercritical CO₂ Using Molecular Topology

During the past thirty years, supercritical fluid technology, as one of the green separate technology, has made great progress in the application and theory. But the study on the equilibrium of solid and solid mixture in supercritical fluid continue to be a very important part in the fields of the supercritical fluids because it can provide key informations for designing and building up any practical supercritical separation processes. Therefore study on the equilibrium of solid and solid mixture in supercritical CO₂ with and without cosolvent has been carried out to deepen the fundamental research, and the major works is presented as follows:As for the equilibrium research aspect, this study is one part of our long-term objective, which is to predict the solute solubility with different functional groups in supercritical CO₂. In the anterior study, the functional groups, such as hydroxyl, carboxyl, were studied, and in this parper thesulfonamide was studied.The investigated single solute included p-methylbenzenesulfonamide, p-aminobenzenesulfonamide and p-aminobenzene sulfonic acid, and the investigated solid mixture system is p-methylbenzenesulfonamide + p-aminobenzenesulfonamide (1:1 equal-molar mixed). The cosolvent effect of pure methanol, ethanol, ethanediol, and acetone to the pure solute or solute mixture is included. The experimental temperatures are 308.15, 318.15 and 328.15 K, and the pressure ranging from 8 to 21 MPa, 174 data points had been measured in this thesis.The effect of temperature, pressure on the solubility of single solute in pure supercritical CO₂ was investigated, and the influence of species, concentration and temperature on the effect of cosolvent was also studied. This paper used the Chrastil equation, the Modified Chrastil equation, the M-T equation, the K-J equation to correlate the solubility in the supercritical CO₂, and all the AARD was less than 5.9%.For the study of solid mixture in the ternary system, the results show that the solubility of a given solid in a ternary system increased relative to the value of the corresponding binary system, that is each component in the mixture can be treated as a special "solid cosolvent" for the other one, and was in proportion to the solubilities of the other solid in the ternary system. The reason for the solubility enhancement of each component is explained.Based on the cross-sectional study on the structural chemistry and topology theory, the novel valence had been defined and then some revised molecular connectivity indices (RMCIs) had been established. After inserting RMCIs into density-based models, some new models had been consequently exploited, and then the inductive relation had been used to predict the solubility data for the aromatic compounds which appeared in this paper. The application of RMCIs in other supercritical fluid had also been considered in this thesis.