ABSTRACT
Critical fluids are substances held above their critical temperature (Tc) and pressure (Pc) or liquids sustained in their liquid state by the application of pressure, which can be used for the extraction of natural products or as an alternative reaction medium. By far the most utilized critical fluid has been supercritical carbon dioxide (SC-CO2) or its liquified analogue (LCO2), due to its benign effect on the environment, low toxicity, nonflammability, and compatibility with processed foodstuffs. Several well-known applications of the technology exist, including the decaffeination of coffee [1], extraction of hop essence for flavoring [2], production of spice and aroma concentrates [3], and isolation of natural antioxidants [4]. More recently, critical fluids have been applied for the production of fine particles, or as a versatile reaction medium, and for the modification of novel materials such as polymers and cements.
