Supercritical fluids synthetic activity

Supercritical fluid extraction (SFE) is a separation technique that uses sc-fluids as separating solvents. Supercritical fluids can replace other solvents in many purification procedures, even in countercurrent extraction. In synthetic chemistry, SFE can be an alternative to conventional methods for purification/isolation of complex products, for example pharmaceuticals, nutraceuticals and vitamins [12, 18j. Since SFE is still quite a young discipline, physical properties and basic parameters for many interesting compounds and mixtures are not yet known (in contrast to classical methods like distillations). Therefore, it must be pointed out that for all applications of sc-fluids the phase equilibria have to be determined properly. Unfortunately, for many technical or industrial applications of procedures based on supercritical fluids, the basic parameters are often not yet known. For industrial implementation, scale-up, miniplant, or pilot plant activities, it is absolutely necessary to have information about phase behaviour, solubility, energy balances and... 

Reactions under supercritical conditions have been used for large scale industrial production for most of the 20th century, but the application of supercritical fluids (SCFs) in the chemical synthesis of complex organic molecules or specialized materials is only just emerging. Research in this field has been particularly active in the last decade of this century. This book is intended to introduce the reader to the wide range of opportunities provided by the various synthetic methodologies developed so far. 

The breakthrough volxame trends for many sorbate types on the porous polymeric sorbents indicate a limited trapping capacity in the supercritical fluid CO2 above 200 atmospheres. Fractionation and selective retention on these sorbents seems only possible below this specified pressure limit for the odoriferous solutes examined in this study. Adsorbent surface area appears to be the most significant factor contributing to the retention of sorbates on these sorbents as well as activated carbon. For certain synthetic adsorbents (Tenax, XAD-2) employed in this study, pressure-induced morphological changes in the polymer matrix lead to an increase in the sorption capacity, and hence to an increase in breakthrough volumes at intermediate pressures. 

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