Process microreactors

The same features were found for pilot-size microreactor operation (see Figure 5.30). Brightness and transparency were the same, and the color strength could even be increased to 149% [65]. The mean particle size was even smaller than the lab-scale microreactor processing (microreactor D5o = 90nm, s=1.5 batch D5o = 600nm, s = 2.0), probably because of process optimization. 

Residence time distribution can be an important issue in the selection process. Microreactors usually operate at Reynolds numbers lower than 200. In this regime, laminar flow prevails and mass transfer is dominated by molecular diffusion. An injected substance in the channel will dissipate caused by the flow profile in the channel. Hence the input signal will be broadened until it reaches the exit of the channel (Figure 3.2). The extent of such a distribution depends on the channel design. In microchannels the mixing process can then be described by the Fourier number (no axial diffusion, dominating radial diffusion D ). A high Fourier Po number leads to a narrow residence time distribution ... 

To facilitate the synthesis of hbPG for industrial processing, microreactor technology can be used to obtain polymers with molecular weights up to 1500gmoh In this approach, an efficient continuous process is used, which results in significantly reduced experimental effort, albeit with molecular weight limitations. 

Jarosch, K., Tonkovich, A., Perry, S., Kuhlmann, D., and Wang, Y. (2005) Microreactor Technology and Process Intensification, in ACS Symposium Series, vol. 914, American Chemical Society, New York, pp. 258-273. 

The Microreactor a systematic and efficient tool for the transition from Batch to Continuous Process Chem. Eng. Res. Des., 84 (5), 363-369. 

Several reactions have been demonstrated using microreactors. One of the potentially more important is the direct synthesis of MIC from oxygen and methyl formamide over a silver catalyst. Dupont have demonstrated this process using a microreactor cell similar to that described above in which the two reactants are mixed, then heated to 300 °C in a separate layer and subsequently passed through another tube coated with the silver catalyst. The estimated capacity of a single cell with tube diameters of a few millimetres is 18 tpa. 

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. 

Temperature profile of the phenyl boronic acid synthesis along the major steps of the process flow scheme. The difference in the temperatures of the conventional batch and the microreactor processes stand for the reduction in energy consumption and respective heat-transfer equipment when using the latter [10]... 

First mention of microreactors uChem processing at KfK (now FZK) in Karlsruhe first micro heat exchangers manufactured 1939... 

The very first investigations on this topic pointed out that a similar degree of optical purity is achievable for some reactions in microreactor as compared to conventional processing. Hence there is no reason not to investigate a chiral reaction in a micro reactor the feasibility has been proven. 

Use of microreactors for nitration processes, in Proceedings of the 4th International Conference on Microreaction Technology, IMRET 4, pp. 194—200 (5-9 March 2000), AIChE Topical Conf Proc., Atlanta, USA. 

Jahnisch, K., Ehrich, H., Linke, D., Baerns, M., Hessel, V, Morgen-scHWEis, K., Selective gas/liquid-reactions in microreactors, in Proceedings of tfie Inten. Conference on Process Intensification for tfie Cfiemical Industry (13-15 October 2002), Maastricht, The Netherlands. 

Investigation, analysis and optimization of exothermic nitrations in microreactor processes, in Matlosz, M., Ehrfeld, W., Baselt, j. P. (Eds.), Microreaction Technology - IMRET 5 Proc. of the 5th International Conference on Microreaction Technology, pp. 446 54, Springer-Verlag, Berlin (2001). 

P., Development of a microreactor for chemical production, in Ehreeld, W., Rinard, 1. H., Wegeng, R. S. (Eds.), Process Miniaturization 2nd International Conference on Microreaction Technology, IMRET 2, Topical Conf. Preprints, pp. 39-44, AlGhE, New Orleans (1998). 

Garcia, E., Ferrari, F., Garcia, T, Martinez, M., Aracil, J., Use of microreactors in biotransformation processes study of the synthesis of diflycerd mono-laurate ester, in Proceedings of the 4th... 

Activities of the catalysts were measured on a microreactor. About 3 g of catalyst was charged into a reactor and heat-treated in nitrogen at reaction temperature. Acetic acid was added to the process and the reaction was initiated by switching nitrogen to ethylene. Reaction product analyses were performed by an online gas chromatograph equipped with a flame ionization detector (Perkin Elmer Auto System II). 

Fig. 9. Pulse microreactor system for use with 13C-labeled hydrocarbons. D, E, and J are microreactors J contains the catalyst to be used for hydrocarbon skeletal reaction D and E are used, when necessary, to generate the required reactant hydrocarbon from a non-hydrocarbon precursor (e.g., alcohol dehydration in D and olefin hydrogenation in E) reactant injected at C. F is a trap which allows the accumulation of products from several reaction pulses before analysis G is a G.P.C. column, K a katharometer. Traps H collect fractions separated on G for subsequent mass spectrometric study. When generating reactant hydrocarbon in D and E, a two-step process is preferable in which, with J below reaction temperature, the purified reactant hydrocarbon is collected in H, and this is recycled as reactant with D and E below reaction temperature but with J at reaction temperature. After C. Corolleur, S. Corolleur, and F. G. Gault, J. Catal. 24, 385 (1972).

It is well known that liposomes are good candidates for controlled reactions. As lipid-based colloids, they have been used to mimic biomineralization processes [99,100], while as restricted volumes, they have been used as microreactors to synthesize... 

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