Microemulsion systems for catalytic reactions and processes

Abstract

This mini-review shows the diversity of microemulsion systems for catalytic reactions with the potential for process development.

Adsorption of non-ionic surfactant from aqueous solution onto various ultrafiltration membranes

“…Micellar solutions, formed at surfactant concentrations above the critical micelle concentration (cmc), are a new class of reaction media which can be used in catalytic reactions [1][2][3]. The micellar structures can be used, e.g.…”

Ionic Liquid-Based Microemulsions in Catalysis

“…1,2 They are particularly suitable as nanoreactors for many catalytic transformations due to their microstructure, which may vary continuously from spherical to cylindrical, tubular, and bicontinuous oil and water phases. 3 The nanometer-sized oil or water droplets provide highly dynamic nanoreactors, with the interface disintegrating and reforming on a time scale of milliseconds, which can promote favorable reaction kinetics.…”

Superior catalyst recycling in surfactant based multiphase systems – Quo vadis catalyst complex?

“…Moreover, aspects of chemical stability, such as degradation through the presence of oxygen, as well as electro chemical stability of the catalyst complex have to be considered. Regarding the formation and thermomorphic behaviour of microemulsions, a variety of side effects could influence the separation dynamics [9]. It is obvious that for the surfactant concentration certain upper and lower bounds are required to maintain a microemulsion system.…”

“…Examples for the application of microemulsions as reaction system are the hydrogenation of dimethyl itaconate with Rh/TPPTS [10], the Suzuki coupling of 2-bromobenzonitrile and 4-methylbenzeneboronic acid with Pd/ TPPTS [11] and the hydroformylation of 1-dodecene with Rh/SX [12]. For further examples see also [9].…”

“…Additionally, their phase separation behaviour can be manipulated through temperature changes. However, for the application of microemulsion systems their phase behaviour, which not only depends on temperature but also on their composition and the interaction between the surfactant and the catalyst/reactants, has to be studied in detail [9]. Among the available green solvents, microemulsion systems, easily tuneable by the selection of an appropriate surfactant, show superior characteristics for catalytic reactions and processes in aqueous media.…”