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Solubility parameters may be useful to simplify very difficult phase equilibria. If you have two chiral salts, two chiral acids, an organic solvent, and CO2, you vary the pressure and temperature as well as composition ...this is a pretty difficult phase equilibrium. But we need to describe it somehow because the practice shows that it gives excellent purities if all parameters are correctly set. 

The paper shows how to reduce the number of experiments needed to find an "optimal" parameter set by using precisely calculated Hansen solubility parameters for CO2-cosolvent mixtures under pressure. 

Chiral compounds (mirror image molecules, like our hands) may have a special ratio when their atmospheric melting points are minimal. This composition is typically the limit of their recrístallization based purification too (like azeotropic composition in distillation). 

Well, we found, that the same happens under CO2 pressure and also if not only CO2 but a cosolvent is present as well. It is an exciting fundamental research result by itself (for the few researchers in this narrow field). But the method development to get these measurements done might be useful when anyone needs to understand any high-pressure multicomponent SLG phase equilibrium. 

© BME, Research Group on Supercritical Fluids, 2015