The Study Of The Solubilities Of Organic Solids In Supercritical Fluids

The solubility of solute in supercritical fluid (SF) is the key point of the design for the apparatus and the scale-up for the processes such as supercritical fluid extraction (SFE) and super micro-particle manufacture using SF's technology. The phase behavior of the organic solid in SF is complex as an asymmetry solute, and it is important to study the solubility of organic solid in SF. The experimental apparatus and the calculating models on it have been studied in this dissertation.Based on the dynamic methods, we developed a novel apparatus, which can be used to study the solubility of solute in SF and to study the SFE. The apparatus has three strongpoints below. Firstly, all the controlling valves of the apparatus were integrated in the block designed specially, which making it practicable to control integratively, to reduce the length of the pipeline, and to set and operate it easily. Besides, the cells have been connected by the quick opening structure of cells stripped easily, which making it ease to strip and rinse them. Then, the apparatus has the advance of the multi-processes of inputting and outputting at different places. Lastly, the different volume cells adopted meets the different requirements of the measurement of solid solubility in SF and the SFE.The four accomplishments have been done on the calculating models.Firstly, a simple model with three adjustable parameters has been developed to calculate the solubility of the organic solid in SF with entrainer, based on modifying the Soave model. To the individual system, the parameters can be simplified to one of the vapor pressure of organic solid, whose natural logarithm being the linear function of the mole fraction of entrainer.Secondly, with the solubility data of two fatty acids and three trifluoromethylbenzoic acid isomers in SF as the sample sets, the wavelet neural networks (WNN) applied usually was optimized on the items following.① Without thinking of the SF's influence, the input parameters of the WNN model simulating the solubility of organic solids in SF were optimized as T, P, vs2, Tm,△Hfus 2 ,δ1 and r2, derived from the active coefficient model to calculate the solubility ofsolid in SF, while the parameters being optimized asTm, vs2, △Hfus 2, ω2, Tr2 and Pr2.derived from the equation of state model.② The errors-trial method to determine the nodes of the hidden layer was optimized as the Kolmogorov theorem, which guiding the determination of the nodes of the hidden layer theoretically.③ The discrete Morlet wavelet function was optimized as active function of the hidden layer through calculating.④ The partial momentum and self-adaptive BP arithmetic brought forward by the author was adopted, which fasting the calculating velocity and improving the simulating accuracy of the WNN model.Thirdly, the optimized WNN model was applied to simulate the solubilities of organic solids in SF.① The optimized WNN model can correlate and predict the most of the solubilities of the organic solids in 24 single systems including SF, but the classical thermal models used in literature correlated it only.② The optimized WNN model was applied to simulate the solubilities of organic solids in 35 single systems including SF and entrainer, with the better results than classical thermal models.③ The optimized WNN model was applied to simulate the solubilities of organic solids in 15 single systems including SF simultaneously, with the better correlative results and the worse predictive results.Lastly, the optimized WNN model was used to correlate the solubility of naproxen in 4 systems of SC CO2 with the other cosolvent and predict the solubility of naproxen in SC CO2 with ethanol, with the Solvatochromic parameters of cosolvent a, β andπ* and the solubility parameters δd, δp and δh being adopted as the major influencing factors, respectively. The least average absolute relative deviations (AARD) predicted by the former is less far than that predicted by the latter, which deducing that Solvatochromic parameters of cosolvent a, β and π* are the major influencing factors to the solubility of naproxen in SC CO2 with cosolvent.Besides, with the molecular structure of the organic solid and the entrainer being analyzed, a rule for selecting entrainer was brought forward by the author, which including three parts below. ①The entrainer with the bigger β should be selected for the acid organic solid.②The entrainer with the bigger α should be selected for the alkaline organic solid including amidocyanogen. ③The Solvatochromic parameters of cosolvent α,β and π* must be considered simultaneously for the amphiprotic organic solid.