Membrane reactors operational features

All peptide-catalyzed enone epoxidations described so far were performed using insoluble, statistically polymerized materials (neat or on solid supports). One can, on the other hand, envisage (i) generation of solubilized poly-amino acids by attachment to polyethylene glycols (PEG) and (ii) selective construction of amino acid oligomers by standard peptide synthesis-linked to a solid support, to a soluble PEG, or neat as a well-defined oligopeptide. Both approaches have been used. The former affords synthetically useful and soluble catalysts with the interesting feature that the materials can be kept in membrane reactors for continuously oper-... 

Several operational features of membrane reactors were listed in an earlier section. We consider a few important ones here. 

A membrane (bio)reactor is a piece of chemical equipment in which a chemical or biochemical reaction, coupled with the separation features of a membrane system, allows the addition of a reactant or the removal of products from the reaction environment. Membrane reactors and bioreactors are, therefore, an example of the combination of two operations in a single... 

Immobilized enzyme membrane reactor 425 Operational features 425... 

An interesting feature of packed bed membrane reactors is the possibility to operate them in a reverse flow mode, integrating the reaction and separation with the recuperative heat exchange inside the reactor. This operational mode is quite interesting for partial oxidation of methane as indicated by Smit et al. [10]. In fact, as stated by the authors, in conventional POM systems air and CH4 feed streams have to be preheated to the reaction temperature, while the POM reaction being only slightly exothermic, the external heat transfer between feed... 

The rising need for new separation processes for the biotechnology industry and the increasing attention towards development of new industrial eruyme processes demonstrate a potential for the use of liquid membranes (LMs). This technique is particularly appropriate for multiple enzyme / cofactor systems since any number of enzymes as well as other molecules can be coencapsulated. This paper focuses on the application of LMs for enzyme encapsulation. The formulation and properties of LMs are first introduced for those unfamiliar with the technique. Special attention is paid to carrier-facilitated transport of amino acids in LMs, since this is a central feature involved in the operation of many LM encapsulated enzyme bioreactor systems. Current work in this laboratory with a tyrosinase/ ascorbate system for isolation of reactive intermediate oxidation products related to L-DOPA is discussed. A brief review of previous LM enzyme systems and reactor configurations is included for reference. 

The SYMPHONY/Multiplex (Figure 8), introduced in 1993, is a batch (Boc/Fmoc peptide synthesizer with 12 independent reaction vessels (49). The key component is the patented matrix valve system that enables different solutions to be transferred to each of the 12 reactors simultaneously. This feature allows the assembly of 12 different peptides under optimal conditions for each sequence with regard to scales and customized coupling reactions. Solution flow is controlled via chemically resistant membrane valves arranged to provide a matrix system with common solution ports but separate delivery lines for each reaction vessel. A combination of gas pressure and an external vacuum pump operates the valve system. Solution transfer is achieved by nitrogen pressure. 

The main feature of the refuelling system Is the refuelling pond which Is situated Immediately above the standpipes, as shown In Fig. 13. The tops of the standpipes are built Into a membrane plate which forms the boundary of the pond during refuelling operations. During normal operation of the reactor, the tops of the standpipes are isolated from the pond water by a removable dished plate which normally forms the base of the pond. 

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