Reactor microstructured

Of course, the benefits of microfabricated and stractured reactors are also applicable to even larger scale processes. For example, Evonik s development of a production-scale microstructured reactor for vinyl acetate manufacture (150000t per annum) claims depreciation and operating cost savings of 3 million per year [25]. 

Recently, microstructured reactors have stepped into chemical production [4] and thus microreactor process and plant design, including economic incentives, is the issue at this time. For this purpose, large-capacity microstructured apparatus is needed ( micro inside, fist- to shoebox size outside ) and plant concepts have to be proposed which include all process steps. 

Five different types of reactors, including tube reactors, static mixers and a microstructured reactor, were tested for the synthesis of an intermediate to 3deld a quinolone antibiotic drug, named Gemifloxacin (FACTIVE ) [13,14]. 

Among several types of reactors investigated, the microstructured reactor was successfully applied to the synthesis of a pharmaceutical intermediate via a fast exothermic Boc protecting reaction step. The reaction temperature was isothermally controlled at 15°C. By using the microstructured reactor the heat of reaction was completely removed so that virtually no byproducts were produced during the reaction. Conversions as high as 96% were achieved. The micro-reactor operation can be compared with other reactors, however, which need to be operated at 0°C or -20°C to avoid side reactions. 

Fig. 4 Production-type microstructured reactor for throughput at 1,700 kg h and transfer of a power of 100 kW. This apparatus was used for manufacture of a high-value product for plastics industry at DSM in Linz/Austria [17]...

Eichtner, M., Benzinger, W., Hass-Santo, K., Wunsch, R., Schubert, K., Functional coatings for microstructure reactors and heat exchangers, in Ehrfeld, W. (Ed.), Microreaction Technology 3rd International Conference on Microreaction Technology, Proc. of IMRET 3,... 

A Pt/AljOj coated microstructured reactor/heat exchanger for the controlled H2/02-reaction in the explosion regime, in Ehreeld, W., Rinaed, I. H., Wegeng,... 

Gorke, O., Peeieer, P., Schubert, K., Determination of kinetic data in the isothermal microstructure reactor based on the example of catalyzed oxidation of hydrogen, in Proceedings of the 6th International Conference on Microreaction Technology, IMRET 6, pp. 262-274 (11-14 March 2002),... 

Rebrov, E. V., Duinkerke, S.A., de Croon, M. H. J. M., Schouten, J. C., Optimization of heat transfer characteristics, flow distribution, and reaction processing for a microstructured reactor/ heat-exchanger for optimal peformance in platinum catalyzed ammonia oxidation, Chem. Eng. 93 (2003) 201-216. 

Membrane reactors are known on the macro scale for combining reaction and separation, with additional profits for the whole process as compared with the same separate functions. Microstructured reactors with permeable membranes are used in the same way, e.g. to increase conversion above the equilibrium limit of sole reaction [8, 10, 11, 83]. One way to achieve this is by preparing thin membranes over the pores of a mesh, e.g. by thin-fihn deposition techniques, separating reactant and product streams [11]. 

Eheich, H., Linke, D., Moegen-scHWEis, K., Baerns, M., Jahnisch, K., Application of microstructured reactor technology for the photochemical... 

GP 12] [R 15] For the synthesis of methyl isocyanate from methylformamide similar conversions as for the conventional synthesis could be determined at low selectivities [71]. One reason for this is seen in the non-ideal temperature profiles within the reaction zone of the microstructured reactor packing. 

Hessel, V., Loeb, R, Loewe, H. (2005) Development of Microstructured Reactors to Enable Organic Synthesis Rather Than Subduing Chemistry. Current Organic Chemistry, 9(8), 765-787. 

Ehrich H, Linke C, Morgenschweis K, Baerns M, Jahnisch K (2002) Application of Microstructured Reactor Technology for the Photochemical Chlorination of Alkylaromatics. Chimia 56 647-653... 

Jahnisch K, Baerns M, Hessel V, Ehrfeld W, Haverkamp V, Lowe H, Wille C, Guber A (2000) Direct Fluorination of Toluene Using Elemental Fluorine in Gas/Liquid Microreactors. J Fluor Chem 105 117-128 Jahnisch K, Hessel V, Lowe H, Baerns M (2004) Chemistry in Microstructured Reactors. Angew Chem Int Ed 43 406 -46 Jensen KF (2001) Microreaction Engineering - is Small Better Chem Eng Sci 56 293-303... 

Kiwi-Minsker L, Renken A (2005) Microstructured reactors for catalytic reactions. Catal Today 110 2-14... 

In the last few years, the corresponding process technology and plants for microstructured reactors have been established, both by new customized process-flow environments from specialized providers (see Fig. 1) and by retrofit into existing plants at the company site. 

The relevant shares in the cost calculations change when microprocess technology approaches large-scale chemical production (U. Krtschil et al., unpublished data). Reactor fabrication at a competitive cost becomes crucial and is among the main cost drivers. The corresponding costs here go with the overall size of the microstructured reactor and with its number. 

Figure 4 shows the impact of process intensification for this hypothetical case. With a temperature increase of only 41°C, the number of reactors for such comparatively big units is reduced from 20, hardly feasible in view of costs and process control, to four, feasible for the same reasons. Thus, the costs decrease by almost a factor of five (not exactly, since fixed costs have a small share). Another 21°C temperature increase halves the number of reactors again, and at 249°C, which is 149°C higher than the base temperature, an equivalent of 0.2 micro-structured reactors is needed. This means that practically one micro-structured reactor is taken and either reduced in plate number or in the overall dimensions. The costs of all microstructured reactors scales largely with their number only at very low numbers do fixed costs for microfabrication lead to a leveling off of the cost reduction. 

Microstructured reactors made it possible to take advantage of the fast kinetics of the Michael addition reaction, while still ensuring efficient heat removal and avoiding thermal overshooting. Yields ranging from 95% to 100% were obtained, at reaction times of 1-10 min instead of the 24-h batch operation a high-p,T operation was established. High... 

Another pilot microstructured reactor uses a smart scale-up of the reactor plate dimensions by a factor of 3.3, each for the width and channel length (see Fig. 13). Stacking further plates is here one concept for future production reactors with another tenfold increase in structured area. 

Hessel V, Hofmann C, Lob P, Lohndorf J, Lowe H, Ziogas A (2005b) Aqueous Kolbe-Schmitt synthesis using resorcinol in a micro-reactor laboratory rig under high-p,T conditions. Org Proc Res Dev 9 479 189 Hessel V, Lob P, Lowe H (2005c) Development of microstructured reactors to enable organic synthesis rather than subduing chemistry. Curr Org Chem 9 765-787... 

Jahnisch K, Hessel V, Lowe H, Baerns M (2004) Chemistry in microstructured reactors. Ang Chem Int Ed 43 406 146... 

Lowe H, Hessel V, Hubbard S, Lob P (2006) Addition of secondary amines to a, 3-unsaturated carbonyl compounds and nitriles by using microstructured reactors. Org Proc Res Dev 10 1144-1152... 

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