In recent decades there has been a significant increase in the energy efficiency of the process industry by optimization of unit operations. In many cases the limits of what can be done on a unit-operation scale have been reached. To develop chemical production routes and products that consumes less of the resources of nature and minimizes the risks for human health or environment, either during manufacture or during or after functional use of the chemical. Within the framework of sustainable process technology two important directives exist, viz. process intensification and catalyst improvement. Process intensification is a novel design philosophy which aims to revolutionize process engineering by revisiting the fundamentals of fluid dynamics and transport phenomena.
[...] Since micro reactors generally can be operated within an extremely wide range of operating conditions, they are powerful tools for process development and the search for novel process routes. And because of their small dimensions, they behave like flame arresters and allow access to controlled reactions in the explosive regime. Using micro reactors scaling-up bottlenecks are avoided. A process in a micro reactor can be used to produce pilot-plant or even production quantities. Yet no time is needed for transferring a process in a micro reactor from research on the lab scale to pilot and production scale." APPLICATONS The best example for application of micro reactor is pharmaceutical industry, where small amount of product required. [...]
[...] Evaluation of new catalysts in conventional reactors typically takes a week or more per catalyst, and many groups are now exploring the potential of micro reactors for faster screening of hundreds or thousands of catalysts in parallel. For highly exothermic catalytic reactions, efficient heat transfer in micro reactors allows them to be done safely in small volumes. For example, the safe and efficient platinum catalyzed oxidation of hydrogen in quartz/glass micro reactors at temperatures above 1000°C. Diazotizations: Of huge importance in industry, diazotization of aromatic amines is fraught with difficulties owing to the explosive nature of diazonium intermediates. [...]
[...] The particular features of micro reactors, such as the large driving forces for heat and mass transport and the high surface-area-to-volume ratio, stimulate the use of these devices as new tools in chemical product research and process development. For example, micro reactors are well suited for rapid screening of materials and catalysts, for measuring intrinsic reaction kinetics, and for discovering new process chemistries. An additional advantage is that micro structured chemical systems may be easily integrated with dedicated instrumentation, sensors and actuators, in small bench top units, requiring less fume hood space and fewer utilities. [...]
[...] Micro reactors have various applications in process industries such as pharmaceutical industry, polymer industry and other industries which required small amounts of product. What is process intensification? To increase energy efficiency, it will be necessary to concentrate the various physical steps and chemical reactions into a single process step that makes only the desired product. For this purpose, new technologies are needed that fundamentally and radically change the industrial processes. This combination of unit operations is called process intensification. Process intensification involves the development of new compact devices and techniques that will lead to substantial improvements in the production processes, reductions in the size of production equipment, lower investment costs, lower energy use and waste production, and finally to more sustainable technologies. [...]
[...] Various chemical reactions of pharmaceutical interest will be used to illustrate the advantages that micro reactors offer for the rapid optimization of reactions, in which the product is typically produced in higher yield and purity. Some of the reactions are given below. Direct fluorination: It is too dangerous to be carried out this reaction at industrial scales. By using micro reactors some of the problems can be overcome. They are to fluorinate organic compounds directly including monofluorination of a 1,3-dicarbonyl compound, which produced a yield of more than 70 per cent. [...]
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