Catalytic Reaction with Simultaneous Product Extraction

Catalytic Reaction with Simultaneous Product Extraction 

More recently. Baker, Tumas, and co-workers published catalytic hydrogenation reactions in a biphasic reaction mixture consisting of the ionic Hquid [BMIM][PFg] and SCCO2 [10]. In the hydrogenation of 1-decene with Wilkinson s catalyst [RhCl(PPh3)3] at 50 °C and 48 bar H2 (total pressure 207 bar), conversion of 98 % 

25°C/ 5bar after reaction extraction with SCCO2 

4 Multiphasic Catalysis with Ionic Liquids in Combination with Compressed CO2 

25°C/ lOObar after reaction extraction with 5,cC02 

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Catalytic Reaction with Simultaneous Product Extraction... 

In particular, for the synthesis of optically pure chemicals, several immobilization techniques have been shown to give stable and active chiral heterogeneous catalysts. A step further has been carried out by Choi et al. [342] who immobilized chiral Co(III) complexes on ZSM-5/Anodisc membranes for the hydrolytic kinetic resolution of terminal epoxides. The salen catalyst, loaded into the macroporous matrix of Anodise by impregnation under vacuum, must exit near the interface of ZSM-5 film to contact with both biphasic reactants such as epoxides and water. Furthermore, the loading of chiral catalyst remains constant during reaction because it cannot diffuse into the pore channel of ZSM-5 crystals and is insoluble in water. The catalytic zeolite composite membrane obtained acts as liquid-liquid contactor, which combines the chemical reaction with the continuous extraction of products simultaneously (see Figure 11.28) the... 

A simultaneous countercurrent movement of solid and gaseous phases makes it possible to enhance the efficiency of an equilibrium limited reaction with only one product (Fig. 4(a)) [34]. A positive effect can be obtained for the reaction A B if the catalyst has a higher adsorption capacity for B than for A. In this case, the product B will be collected mainly in the upper part of the reactor, while some fraction of the reactant A will move down with the catalyst. Better performance is achieved when the reactants are fed at some side port of the column inert carrier gas comes to the bottom and the component B is stripped off the catalyst leaving the column (Fig 4(a)). The technique was verified experimentally for the hydrogenation of 1,3,5-trimethylbenzene to 1,3,5-trimethylcyclohexane over a supported platinum catalyst [34]. High purity product can be extracted after the catalytic reactor, and overequilibrium conversion can be obtained at certain operating conditions. 

CDTech uses catalytic distillation to convert isobutene and methanol to MTBE, where the simultaneous reaction and fractionation of MTBE reactants and products takes place [51], A block diagram of this process is shown in Figure 3.31. The C4 feed from catalytic crackers undergoes fractionation to extract deleterious nitrogen compounds. It is then mixed with methanol in a BP reactor where 90% of the equilibrium reaction takes place. The reactor effluent is fed to the catalytic distillation (CD) tower where an overall isobutene conversion of 97% is achieved. The catalyst used is a conventional ion-exchange resin. This process selectively removes MTBE from the product to overcome the chemical equilibrium limitation of the reversible reaction. The MTBE product stream is further fiactionated to remove pentanes, which are sent to gasoline blending, whereas the raffinate from the catalytic distillation tower is washed with water and then fractionated to recover the methanol. 

In Section 4.2.2.2 some processes are described in which the organic products are separated - simultaneously or successively - by extraction with a nonpolar extractant. In the cases presented in this section, not the product but the catalyst will be extracted and recycled to the reactor. Theoretically, this can be done simultaneously in the reactor, as shown in Figure 12. However, this arrangement is highly unfavorable, because it means that the catalyst is taken away from the reaction medium during the catalytic conversion. The successive variant, shown in Figure 13, makes much more sense the reaction is first carried out in the reaction unit, then the catalyst is extracted by an extractant which does not dissolve the products C... 

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