Microchemical process

A micro reactor concept proposed by MIT and DuPont on the basis of electronic circuits is the most prominent among the examples listed for the hybrid approach [19,101]. The so-called turnkey multiple micro-reactor test station relies on the use of standard components originating from the semiconductor industry for microchemical processing, the construction being oriented at the concept of printed circuit boards. 

However, it is not only knowledge transfer on the technology itself which impacts on society microchemical processing wiU have repercussions on our wealth, health, and environment. From the late 1960s (first prognoses on limits of production... 

Example of microchemical processes 2.2.1 Molecular transport in microspace... 

Then, a pilot plant with a capacity of lOt/a was build for the Swern-Moffat oxidation [57,58]. The yield of the batch process is 83% at — 70 °C, whereas the microchemical process achieved a yield of 88% at 20 °C. The pilot plant was operated under stable reaction conditions for a long run with similar product yields as in the laboratory experiment (see Figure 5.23). 

Deposition and etching of Si can be accomplished at line widths <0.4 Jim (204). Practical applications of this laser microchemical processing include ohmic contact formation on p-InP (p-type indium phosphide) and hard-surface-mask repair (205). Further details on recent applications of this process can be found (204-206). 

Desktop Chemical Factory, Fig. 3 Glass-based microreactor system, (a) Scale-up of a microreactor system manufactured by Coming Inc., (b) A systematic flow chart for integrated microchemical processing [9]... 

Robots can raise the productivity up to tested substances per day. The throughput is limited by inertia of the robotic arm, which puts constraints on the movement speed. Several robots may operate in parallel, but besides increasing the cost, this complicates the procedures by restrictions to avoid mutual interference. With the general current trends toward the small-scale microchemical processes - some authors mention only submilhmeter distances between neighboring titre-plate wells - robots may encounter their limits not only of motion speed but also of positioning accuracy. Of course, introducing the robots increases signiflcantly the initial capital cost of the laboratory. 

Many researchers have studied the interfacial science and technology of laminar flow in microfluidics [8]. Interfacial polymerization and the subsequent formation of solid micro structures, such as membranes and fibers in a laminar flow system, are very interesting techniques because the bottom-up method through polymerization is suitable for the formation of miniature structures in a microspace [3]. The development of such microstructure systems plays an important role for the integration of various microfluidic operations and microchemical processing [9]. For instance, membrane formation in a microchannel and further modification has a strong potential for useful functions such as microseparation, microreaction and biochemical analysis [8-10]. Here, we will introduce several reports on polyamide and protein membrane formation through interfadal polycondensation in a microflow. 

In general, the application of microfluidic devices in chemical and pharmaceutical synthesis can be roughly divided into tv o areas microchemical processing and lab-on-a-chip applications. 

Microchemical processing mainly emphasizes the exploitation of the well-knovm benefits of miniaturization such as very good heat and mass transport characteristics in a continuous process [1]. Microfluidic devices are used for process understanding, process optimization and development and Anally production of specific products. The main reasons for employing microchemical processes on the laboratory and industrial scales are the following ... 

This huge potential makes the neglect of process analysis in microprocess engineering even more astonishing. Today, only very little literature is available that describes the use of PAT in microchemical processes. It seems that flieir obvious advantages have not yet been noticed, although the integration of PAT units into microreactors is well known in the p-TAS community. 

Optical Spectroscopy in Microchemical Processes 123 Table 6.1 Comparison of the different optical spectroscopic techniques. 

Moreover, the use of in-line spectroscopic techniques in microchemical processes allows real-time monitoring of analytes and their concentrations in real reaction mixtures. Depending on the characteristics of the chemical process and the objectives of in-line analytical investigations, appropriate calibration methods and procedures might be required. 

First, the results of a four-stage potential analysis developed by Merck (Darmstadt, Germany), together with the Technical University of Clausthal are discussed. This analysis starts with a technological evaluation of MRT to achieve finally a business view [4], Next, a short summary of a study from the fine chemical and pharmaceutical company Lonza (Visp, Switzerland) dealing with capital (CAPEX) and operational (OPEX) costs for several pilot microchemical processes is presented [5]. The picture is rounded off by cost analyses of the chemical producer AzurChem, prepared in... 

For the analysis of the decisive variables of a profitable microchemical process, different case scenarios were studied based on the existing manufacturing process. The calculations were based on an average yield of the process which could be achieved of 75%, including not only the reaction yield but also the loss of the product within the purification process. 

Setting the total costs of the real microchemical process at 100%, a dramatic decline in costs can be achieved for the three different scenarios with increased capacity (Figure 13.6). The total costs are reduced to one-third (33%) for the microchemical... 

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