Multiphase extraction properties

The results obtained with the reported extraction model showed that the separation of charged species is possible, provided a suitable ligand hydrophobicity. Further analytical developments of these multiphase extraction systems will require an accurate investigation of the equilibria and kinetic processes occurring at the interfaces, as well as the study of the micellar structure and properties of the host aggregates. 

Obviously, there are many good reasons to study ionic liquids as alternative solvents in transition metal-catalyzed reactions. Besides the engineering advantage of their nonvolatile natures, the investigation of new biphasic reactions with an ionic catalyst phase is of special interest. The possibility of adjusting solubility properties by different cation/anion combinations permits systematic optimization of the biphasic reaction (with regard, for example, to product selectivity). Attractive options to improve selectivity in multiphase reactions derive from the preferential solubility of only one reactant in the catalyst solvent or from the in situ extraction of reaction intermediates from the catalyst layer. Moreover, the application of an ionic liquid catalyst layer permits a biphasic reaction mode in many cases where this would not be possible with water or polar organic solvents (due to incompatibility with the catalyst or problems with substrate solubility, for example). 

The use of supercritical-fluid-extraction techniques in the fractionation of polysiloxanes has been demonstrated by the data presented. The poly-dispersities of the fractions were comparable with those generally attainable only by anionic-polymerization techniques, with which the incorporation of two functional groups is often difficult to attain. The ability to isolate these well-defined fractions will lead to important fundamental studies on structure-property relationships in multiphase copolymer systems. 

The versatility of ILs has driven increasing interest in using them in extraction and multiphasic homogeneous catalytic reactions [104] where one phase is chosen to dissolve the catalyst and be immiscible with the second phase which contains the reactant and products. Such processes occur at the interface between the IL and the overlying aqueous or organic phase, and are dependent on the access of the material to the surface and the transfer of material across the interface. A clearer understanding of the mechanisms behind these processes requires a more detailed examination of the surface properties of the ionic liquids. 

This paper is organized into three parts. Purification techniques are outlined briefly in comparison to aqueous extraction, followed by a review of properties and work in multiphase systems with emphasis on the purification of proteins. Finally, recent work... 

The process has been briefly described by Turunen (1997) as an example of process intensification activities. Most of the hydrogen peroxide production is nowadays based on the anthraquinone method. The differences between the technologies include mainly differences in solvents, catalysts and equipment types and details. The process has less than ten main unit operations including two multiphase reactors, liquid-liquid extraction, gas desorption, distillation and filtration. The process conditions do not include high temperatures or pressures. The necessary properties are not readily available from literature because of the large number of components in the process liquid. However, the measurement of the most of the properties is relatively easy because of the mild conditions. The number of components which take part in the main production reactions and separation steps is small. Therefore it was possible to develop reliable models for most of the unit operations and to base the design on these nnodels. However, the side reactions and by-products involve complicated chemistry and... 

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