Micelles/Micellar Catalysis

Abstract

AbstractThe contribution gives a survey of the aggregation of surfactants in aqueous and organic media and the reactivity control in such self‐organized systems. Several examples of micellar catalysis in aqueous surfactant assemblies are discussed for solvolytic reactions, oxidation reactions, reductions, carbon–carbon coupling reactions, and spontaneous unimolecular reactions. The influence of surfactant assemblies can be an alteration of the reaction rate (activity), the selectivity (chemo‐, regio‐, and stereoselectivity) of chemical and photophysical pathways, and of quantum efficiency and ionization potentials. Reverse micelles are formed by surfactants in organic solvents with a low content of water and are of interest in an entrapment of enzymes. Comparable are microemulsions as surfactant‐initiated multiphase systems with water as component. They are reaction media with a high variety of polarity and a relatively high mass capacity. Organized media have a practical importance for polymerization reactions because of the regularity of the hydrophobic interior. Artificial enzymes with amphiphilic properties were developed in analogy to natural membrane systems. A typical membrane‐mimetic adaption is also the use of surfactant aggregates as photochemical microreactors. New trends are mentioned to give developments of practical importance, e.g., reactions in immobilized amphiphiles, micellar phase‐transfer catalysis, and micellar autocatalysis.