Reactor single bead

Figure 11.19 384-parallel single-bead reactor with independent microreaction chambers and integrated flow restrictors. Typical bead diameter 1 mm. 

Typical configuration of a single-bead reactor snown a w... 

Figure 11.21 Results of high-throughput screening of catalysts in a 384-parallel single-bead reactor in a partial oxidation reaction, (a) Arrangement of inactive and total oxidation catalysts in the reactor, (b) screening results for the conversion of a hydrocarbon at 400°C, 1 mL/min per bead.

Figure 11.23 Comparison of a 384-parallel single-bead reactor and a 48-parallel secondary screening reactor for a set of reference catalysts in a partial oxidation reaction.

Figure 7.4. Single-bead IR spectra of the product for the reaction 3 at various times on PS = polystyrene, AP = ArgoPore, Tube = Microtube reactor, and PS-PEG = polystyrene-polyethyleneglycol resin.

Several sets of experiments were carried out to evaluate the performance of the different single-bead reactors in continuous flow catalytic experiments. 2% Pd/ Al203-beads (1 mm diameter) were prepared from a-Al203 by wet impregnation and subsequent calcination at 450 °C. The mass of one catalytic bead is ca. 700 pg. 

In single bead string reactors the enzyme is bound both to the reactor wall and to a carrier within the reactor. Compared with open tubular reactors this reactor type provides a higher conversion at lower sample mixing. 

Packed bed reactors [51] incorporate beads, and the presence of these solid materials in the analytical path also has a beneficial influence on the flow pattern, reducing sample broadening and, hence, sample dispersion. However, hydrodynamic pressure tends to be increased, especially when small particles and/or particles with heterogeneous sizes are used. Single bead string reactors [5] were proposed to circumvent this drawback. These reactors utilise large (particle diameters about 70% or the tube inner... 

Analysis of Eq. 3.6 reveals that the function C =/(f) tends to be Gaussian and approaches the Taylor model when N increases. On the other hand, the validity of this equation is dubious for low N values, as the shape of the curve skews. This means that the model provides good results when applied to unsegmented-flow systems with long reactors but fails to describe sample dispersion in short reactors. This limitation of the model is not as relevant to efficient mixing devices such as the single bead string reactor [5,52],... 

J.M. Reijn, W.E. van der Linden, H. Poppe, Dispersion in open tubes and tubes packed with large glass beads. The single bead string reactor, Anal. Chim. Acta 123 (1981) 229. 

Fig. 15.11 Colorimetric phenol analyser, (a) Details of the distillation unit, condenser and heat exchanger, (b) General scheme of the instrument. A, sampler B, heating bath with heating rod C, distillation head D, condenser E, heat exchanger F, strip-chart recorder G, colorimeter H, coll J, single bead-string reactor K, peristaltic pump (1) wash water (2) sample (3), air (4) phosphoric acid (5) overhead condensate (6) 4-AAP reagent (7) Fe(III) reagent (8) air (9) level control (10) bottoms draw (11) debubbler draw. (Reproduced from [39] with permission of Elsevier).

The coiled tube has so far been the most frequent geometric form of the FIA microreactor. However, it is useful to review all channel geometries (Fig. 2.8). These are straight tube (A), coiled tube (5), mixing chamber (C), single-bead string reactor (D), 3-D or knitted reactor (E)y and imprinted meander (cf. microconduits Section 4.12) or combinations of these geometries. 

Figure 2.8. The microreactor geometries most frequently used in FIA A, straight open tube B, coiled tube C, mixing chamber D, single-bead string reactor (SBSR) and E, knitted reactor. (For an example of the imprinted meandering reactor, see Chapters 3 and 4.)...

A single-bead string reactor (SBSR)(Fig. 2.8D), originally used in postcolumn derivatization [2.3] and later introduced to FIA by Reijn et al. [146], is the most effective device to promote radial mixing in a tubular reactor. The SBSR allows symmetrical peaks to be obtained... 

Single-bead string reactor (40 cm, 0.86 mm id) filled with 0.5 mm glass beads the effective cross-sectional area is different from the nominal one. 

J. M. Reijn, H. Poppe, and W. E. van der Linden, Kinetics in a Single Bead String Reactor for Flow Injection Analysis. Anal. Chem., 56 (1984) 943. 

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