Supercritical Fluid Extraction

Supercritical fluids (SCFs) are increasingly replacing organic solvents, e.g., n -hexane, dichloromethane, chloroform, and so on, that are conventionally used in industrial extraction, purification, and recrystallization operations because of regulatory and environmental pressures on hydrocarbon and ozone-depleting emissions. In natural product extraction and isolation, supercritical fluid extraction (SFE), especially that employing supercritical CO₂ , has become the method of choice. Sophisticated modern technologies allow precise regulation of changes in temperature and pressure, and thus manipulation of solvating property of the SCF, which helps the extraction of natural products of a wide range of polarities. This chapter deals mainly with the application of the SFE technology in the natural product extraction and isolation, and discusses various methodologies with specific examples.