Formation of Organic Solid Particles from Supercritical Fluids.

Supercritical fluids have been used to form various organic solids. There are two types of formation methods: precipitation by rapid expansion of supercritical solutions (RESS) and precipitation by adding supercritical fluids as a gas antisolvent (GAS). RESS method is based on the reduction of solvent power of supercritical fluids by lowering pressure level and can produce very fine particles by controlling crystallization conditions. GAS method is a recrystallization method and exploits the ability of supercritical fluids to lower the solvent power of the liquid for the compounds in solution. As a separation method of solid mixtures the supercritical fluid crystallization has been investigated for the naphtalene-phenanthrene mixture by use of supercritical carbon dioxide.