Conventional batch process

For high vacuum distillation, Eckles et al. [150] suggest using a thin film or conventional batch process for industrial type installations however, there are many tray and packed colunms operating as low as 4 mm Hg, abs Eckles... 

GL 4] [R 5] [P 5] The rate of the fluorination of y0-keto esters is usually correlated with the enol concentration or the rate of enol formation as this species is actually fluorinated [15, 16]. For the fluorination of ethyl 2-chloroacetoacetate in a micro reactor, much higher yields were found as expected from such relationships and as compared with conventional batch processing which has only low conversion. Obviously, the fluorinated metal surface of the micro channel promotes the enol formation. 

In a series of controlled experiments, Dosi et al. used the conversion of glucose to lactic acid as a model for the potential of controlling (automatically by computer) the concentrations of the constituents.45 Nice schematics for the reactor setup and connections to the computer/NIR spectrometer/microhltration unit, etc., are shown. Six cases are described, each using a conventional batch process. Transition from batch mode to automatic was triggered by predefined criteria such as degree of substrate conversion or biomass concentration. Control charts and comparisons of NIR data with conventional assays are given for all six cases. 

In order to study the feasibility of such a quasi-continuous production line, different formulations were tested and compared with a conventional batch process. 

The economic benefit is one of the dominant problems if a micro structured reactor plant is used for chemical production. Without any doubt, an overall flow rate through a micro structured device can be achieved that is comparable to that with a conventional batch process. However, the residence time is very short because of the dimensions of a microstructured device. If the reaction kinetics are slow, an additional device is necessary to increase a dwell time. Hence, much effort should be devoted to increasing the reaction rate instead of transferring the standard protocol to a micro structured reactor [13]. 

Compared to a conventional batch reactor, there is less hazardous material in the reactor at any time, and the consequences of power loss, loss of temperature control, leaks, and runaway reactions are much less severe. In addition, it is easier to have good temperature control, which can provide a more reproducible, high quality product. Productivity is significantly better than in conventional batch processes since the reactor is polymerizing at its maximum rate most of the time and is normally limited only by heat transfer... 

This new system had been operating industrially since 1973 in Tanabe Seiyaku Co., Ltd. The overall production cost by this system was reduced to above 60% of the conventional batch process using intact cells because of the marked reduction in cost for the preparation of catalysts and of the reduction of labor cost by automation. Furthermore, the procedure employing immobilized cells is advantageous from the standpoint of waste treatment. 

An attractive aspect which has received little attention so far is the aforementioned possibility of mnning reactions in continuous mode under steady-state conditions concerning reactant concentrations by means of membrane techniques. The potential for directing reactions by suppressing side reactions or otherwise controlling selectivities has attractive potential. It must be realized that for applications in the synthesis of fine chemicals such a concept requires additional development (costing time and money) by comparison to established conventional batch processes, and therefore will only be realistic for well-chosen problems with sufficient reward. 

FIGURE 10.62 Conventional batch process for viscose rayon manufacture (schematic). (Courtesy of John Wiley Sons, New York.)... 

If a new plant is to be built, the design will be based on state-of-the-art technology using highly mutated strains of Penicillium chrysogenum growing on glucose (com symp). A conventional batch process will be used unless adaptation to a fed-batch or continuous process appears feasible. A crystalline product will be obtained after solvent extraction of the beer with amyl acetate or butyl acetate. 

Other work (Malik et al., 2004) has focused on the various factors (which are suspected to limit the coal biodesulfurization process rate) on bacterial oxidation of ferrous iron. An attempt has been made to find whether this reaction is inhibited due to the presence of solid particles and/or the release of inorganic components from solids during coal biodesulfurization. The data showed that silicon was responsible for retarding the central step of iron oxidation during coal biodesulfurization. Consequently, operational strategies, which tend to minimize the concentration of toxic inorganic components in the leachate, would be a better option than conventional batch process for enhanced biodesulfurization. 

The microreactor system is the core part on a DCF system in order to achieve better production than a conventional batch process. The choice of appropriate material for a microreactor depends on the desired application. 

The dispersed phase was injected through a 35 pm hole drilled in the acetate sheet. The formulation for the MIP synthesis, containing the template [(J, S)-propranolol], the monomer (methacrylic acid, MAA), the crosslinker (trimethylolpropane trimethacrylate, TRIM), the photoinitiator (2,2-dimethoxy-2-phenylacetophenone, DMPAP) and a porogenic solvent (acetonitrile), was emulsified at the T-junction with a mineral oil (heavy white) and then photopolymerized by UV irradiation in the spiral-like channel. The resulting MIP particles were compared with those obtained with a conventional batch process. The continuous microsystem-assisted process led to near-monodisperse particles (CV <2%), whereas the conventional process gave particles having a broad range of sizes (CV >10%). The same conclusion holds for... 

Most of the known pilot processes in the field of fine chemicals use a micro structured mixer with a coimected tubing or micro heat exchanger. The advantages of this over conventional batch processing are... 

It was noted in the previous chapter (Section 1.4.2.1.) that the polymerization of isobutene could be accomplished only with cationic initiators. Aluminium chloride and boron trifluoride are the preferred initiators for commercial processes the separate addition of a co-catalyst is not generally necessary and adventitious substances possibly fulfil this role. At ordinary temperatures polymerization is extremely rapid and leads to low molecular weight polymers which are viscous oils or sticky solids. However, at low temperature (—80 to — 100°C) high molecular weight material is produced. Even at these low temperatures the reaction is complete in a few seconds and it is necessary to have particularly efficient means of dissipating the heat evolved. Conventional batch processes are unsuitable and continuous processes are used in which only small quantities of reactants are involved at any one moment. In one process (Badische Anilin- Soda-Fabrik A. G.), solutions of isobutene and boron trifluoride in liquid ethylene are mixed on a moving belt so that the polymerizing system is in the form of a thin film and heat is removed by the vaporization of the solvent. The polymer is then mixed with an alkali or ethanol to deactivate the initiator and treated with steam to remove water-soluble contaminants. Another process for polyisobutene (Standard Oil Co. (N.J.) (U.S.A.)) follows closely the procedure outlined in Section 2.10.2. for the manufacture of butyl rubber. 

Fig. 9.2 Block diagram of manufacturing sachharin by conventional batch process of chlorosulphonation of toluene...

In previous studies, it was presumed that a GI POP fabricated by this process would have a refractive index distribution with a tail at the core/cladding boundary, not as steep as that prepared by the conventional batch process [50]. Therefore, the bandwidth of the GI POF obtained by dopant diffusion coextrusion would be inferior to that obtained by the batch process. However, contrary to this expectation, a GI POF without any tail prepared by the process was reported in 2007 [57]. If low-molecular-weight molecules diffuse in a radial direction, their diffusion can be expressed by Fick s diffusion equation... 

Suspension polymerization can rarely be described as a conventional batch process because uniform physical conditions cannot be created instantly. The way in which the ingredients are brought together can affect the polymer properties. Therefore, improvements in the control of product quality may depend on developing better... 

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