CO{sub}2-Expanded Solvents versus Conventional Solvents in Crystalline Polymorph Preparation

摘要

In precipitation processes with compressed fluids much larger and more abrupt changes of solution supersaturation can be achieved than when using conventional liquid solvents, and as a consequence micro- and nanoparticulate materials with a narrow size distribution, unachievable by conventional processes, can be straightforward prepared. By using these "green procedures" it is often possible to prepare, at large scale, materials with a specific internal structure (polymorph, nanostructured composite material, porosity, degree of crystallinity, etc.) unachievable by traditional methods. In this paper we will try to illustrate the great potential of crystallization procedures from CO{sub}2-expanded solvents for the preparation of pure polymorphic forms of molecular materials.