Taken from: http://advtechconsultants.com/SCFImage.jpg Supercritical fluid extraction is used to extract essential oils from plants. A supercritical fluid is a compound that has reached a state where it is no longer a liquid or a gas but is a unique phase that can pass through things like a gas but dissolve things like a liquid.
Supercritical fluid Critical point occurs under conditions such as specific values of pressure and temperature at which no phase boundaries exist. Therefore, the supercritical fluid is any substance at a temperature and pressure above its critical point.
Supercritical Fluids and Organometallic Compounds: From Recovery of Trace Metals to Synthesis of Nanostructured Materials (Supercritical Fluid Science and Technology) by Can Erkey. $208.00. Author: Can Erkey. Publisher: Elsevier Science; 1 edition (October 27, 2011). 248 pages
Supercritical Fluid Nanotechnology : Advances and Applications in Composites and Hybrid Nanomaterials