Batchwise synthesis

For batchwise synthesis, the base matrix used is almost invariably 1% divinylbenzene cross-linked polystyrene (PS). It is relatively inexpensive to produce, swells in the solvents most commonly used in peptide synthesis, namely DCM, DMF, and NMP, and can be readily functionalized using the Friedel-Crafts reaction with chloromethyl, aminomethyl, and benzhydrylamino groups. 

Protein Technologies (batchwise synthesis, pilot scale, and multiple) Shimadzu (multiple)... 

Times are for batchwise synthesis. If a flow apparatus is used, the time is the combined times of a step, eg, 2 x 2 min = 4 min of flow. 

Two processes are commonly used for the production of copper phthalocyanine the phthalic anhydride-urea process patented by ICI [33,34] and the I.G. Farben dinitrile process [48], Both can be carried out continuously or batchwise in a solvent or by melting the starting materials together (bake process). The type and amount of catalyst used are crucial for the yield. Especially effective as catalysts are molybdenum(iv) oxide and ammonium molybdate. Copper salts or copper powder is used as the copper source [35-37] use of copper(i) chloride results in a very smooth synthesis. Use of copper(i) chloride as starting material leads to the formation of small amounts of chloro CuPc. In the absence of base, especially in the bake process, up to 0.5 mol of chlorine can be introduced per mole of CuPc with CuCl, and up to 1 mol with CuCl2. 

A new microwave reactor for batchwise organic synthesis is described in Ref. 712 (Fig. 3.5). Its use permits us to carry out synthetic works or kinetic studies on the 20 100 m L scale, with upper operating limits of 260°C and 10 MPa (100 atm). Microwave-assisted organic reactions can be conducted safely and conveniently, for lengthy periods when required, and in volatile organic solvents. The use of water as a solvent is also explored [712]. 

Figure 3.5 Reactor for batchwise organic synthesis. 1. Reaction vessel 2, top flange 3, cold finger 4, pressure meter 5, magnetron 6, forward/reverse power meters 7, magnetron power supply 8, magnetic stirrer 9, computer 10, optic fiber thermometer 11, load matching device 12, waveguide 13, multimodal cavity (applicator). (From Ref. 712, reproduced with permission.)...

Due to their thermal instability fine chemicals often must be produced in the liquid phase at moderate temperatures. They are generally complex and multifunctional as well as chemo-, regio- and stereoselectivity play an important role. The reactor system of the choice are batch or semi batchwise operated multipurpose units. Bulk chemicals, mostly consisting of relatively small, thermostable molecules, can be produced in continuously operated fixed bed or fluidised bed reactors in the gas-phase allowing much higher space time yields, thus minimising investment costs1. These procedures can hardly be applied to the synthesis of e.g. fine and intermediate chemicals because of the relatively small... 

A survey of recent literature on zeolite membrane preparation reveals that synthesis processes, even for well-known zeolite structures (i.e., MFl, LTA), are still carried out batchwise, using a hydrothermal route to produce a thin layer from hydrogels or sols containing the corresponding nutrients. As a general rule, the reactant mixture in contact with the support changes in composition with time provoking a reduction of the membrane quality. 

Nucleophilic aromatic substitutions are a type of reactions frequently applied in the synthesis of chemical intermediates and fine chemicals. In general, these processes are performed in the liquid phase, batchwise, with dissolved copper salts as catalysts [1]. It is of interest to investigate the possibilities of heterogeneous catalysis, as a more convenient catalyst recycle can thus be achieved. 

In the so-called tea-bag method, originated in 1984 by Houghten et al. [14] for multiple peptide synthesis, the split-pool protocol occurs batchwise on 15 x 22 mm polypropylene mesh packets with pm-sized pores known as tea bags, sealed with resin beads for solid-phase synthesis. This method offers the advantage that a greater quantity of each compound of the library is available at once (up to 500 pmol), which is sufficient for a complete biological and structural characterization. Furthermore, the structural identity of... 

The enzymatic synthesis reaction of l-DOPA is carried out in a batchwise system with cells of E. herbicola with high TPL activity. Since pyruvate, one of the substrates, was unstable in the reaction mixture at a high temperature, low temperature was favored for the synthesis of l-DOPA. The reaction was carried out at 16 °C for 48 h in a reaction mixture containing various amounts of sodium pyruvate, 5 g of ammonium acetate, 0.6 g of pyrocatechol, 0.2 g of sodium sulfite, 0.1 g of EDTA, and cells harvested from 100 ml of broth, in a total volume of 100 ml. The pH was adjusted to 8.0 by the addition of ammonia. At 2-h intervals, sodium pyruvate and pyrocatechol were added to the reaction mixture to maintain the initial concentrations. The maximum synthesis of l-DOPA was obtained when the concentration of sodium pyruvate was kept at 0.5%. The substrates, pyrocatechol and pyruvate, were added at intervals to prevent the denaturation of TPL and to prevent byproduct formation. The addition of sodium sulfite is effective in maintaining the reactor in a reductive state and in preventing the oxidation of the l-DOPA produced. l-DOPA is insoluble in the reaction medium, so it appears as a crystalline precipitate during the reaction, at final amounts reaching 110 g/1 [19-21]. 

Batchwise solid-phase synthesis, the original procedure of SPPS developed by Mer-rifield in 1966. Alternatively, SPPS can also be performed in a continuous-flow mode solid-phase peptide synthesis using resin-flUed columns. 

Many polymers with interesting functionalities have been developed and applied in various fields. At present, a rapid and combinatorial synthesis system with highly controllable polymerization reaction is much required. However, it is generally difficult to control polymerization reactions in conventional batchwise systems. The synthesis of polymer molecules using a microreactor enables strict control of chemical reactions which serves as a model of polymer synthesis. The performance of a microreaction system for polymerization was compared with that of a conventional batchwise... 

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