Design, Synthesis Of Novel CO₂-philic Compound And Investigation On Their Solubility Behavior In Supercritical CO₂

In this paper, the solubility of4,4′-methylene bis（phenyl isocyanate） in ScCO₂was measured in the temperature range of （313to353）K and pressure range of（9.6-16.3）MPa, together with the cloud point2in the temperature range of313to333K. The results indicated that at the same temperature, the solubility of4,4′-methylene bis（phenyl isocyanate） increased with rising pressure because thedensity and solvability of CO₂also increased with pressure in isothermal condition,and at the same pressure, the solubility of4,4′-methylene bis（phenyl isocyanate）decreased with rising temperature because the density and solvability of CO₂alsowent down with temperature in isobaric condition. Meanwhile, the solubility data of4,4′-methylenebis（phenyl isocyanate） were correlated by seven semi-empirical modelslsuch as Chrastil, KJ, SS, del Valle, Bartle, MST, JCF. The correlation resultsindicated that the data of all the models had obtained good results, and among thosemodels, JCF model which contains more parameters about pressure and temperatureare predominant over other models, while those Chrastil type models gave the poorestresult. In the E-ρ type models, MST model fitted better than Bartle model, and thereason can probably be that the temperature had some effects on the density of CO₂tosome extent. Similarly, the SS model gained the best result in Chrastil type models,because it is the only model that had taken the effect of temperature on CO₂’s densityinto account in Chrastil type models.The results obtained by cloud point2was similarto dissolution pressure.Secondly, the dissolution pressure and choud point2of diacetone-D-glucosewere also determined, and the results of cloud point were not satisfying. Therefore,there diacetone-D-glucose derivatives2-4were synthesized, and their dissolutionpressure, cloud point1and2in ScCO₂were studied. It can be found that whencompared to diacetone-D-glucose, the solubilities of compound2-4were greatlyimproved in the same condition, and the corresponding sequence was2>3>4.Meanwhile, the solubility data of diacetone-D-glucose and compound2-4werecorrelated by seven semi-empirical models, and the results showed that JCF modelwas still the best model among the seven models, regardless of the effect of anyinfluential factors. What’s more, the Chrastil type model were found better tocorrelate the solubility data of liquid solutes when compared to solid solutes, whilethe E-ρ type model was more suitable for correlating the data of solid solutes.At last, two kinds of cloud point pressure of compound1-3in ScCO₂were determined, and the calculation results showed that there were no such evidentdifferences between the data consistency of dissolution pressure, cloud point pressure1or cloud point pressure2, despite the fact that cloud point pressure1was in the lead.By and large, JCF model was proved to be the most excellent semi-empirical model inthis work, and cloud point pressure1can correlate solute’s solubility data better thandissolution pressure or cloud point pressure2. This may provide some referenceinformation for other ScCO₂researchers to chose the appropriate semi-empiricalmodel or pressure to correlate solute’s solubility data.