Industrial fine chemical production process

The main driver was to develop a laboratory-scale micro-channel process and transfer it to the pilot-scale, aiming at industrial fine-chemical production [48, 108]. This included fast mixing, efficient heat transfer in context with a fast exothermic reaction, prevention offouling and scale-/numbering-up considerations. By this means, an industrial semi-batch process was transferred to continuous processing. 

Carbon monoxide chemistry has been extensively studied, leading to a wide range of methods used in small scale organic syntheses up to industrial processes.8 Despite the versatility of carbonylation reactions, carbon monoxide suffers from major drawbacks that restricts its utilisation. From an industrial point of view, the cumbersome handling of this toxic gas necessitates very expensive facilities which prevent its use for the majority of fine chemical production processes. An alternative process equivalent to a carbonylation reaction which avoids carbon monoxide introduction into the reactor and that can be used in standard polyvalent type units would be of great interest. Of course, catalyst cost, stability and productivity should also fulfil economic requirements. 

Table 3.12 surveys current industrial applications of enantioselective homogeneous catalysis in fine chemicals production. Most chiral catalyst in Table 3.12 have chiral phosphine ligands (see Fig. 3.54). The DIP AMP ligand, which is used in the production of L-Dopa, one of the first chiral syntheses, possesses phosphorus chirality, (see also Section 4.5.8.1) A number of commercial processes use the BINAP ligand, which has axial chirality. The PNNP ligand, on the other hand, has its chirality centred on the a-phenethyl groups two atoms removed from the phosphorus atoms, which bind to the rhodium ion. Nevertheless, good enantio.selectivity is obtained with this catalyst in the synthesis of L-phenylalanine. 

SCFs will find applications in high cost areas such as fine chemical production. Having said that, marketing can also be an issue. For example, whilst decaffeina-tion of coffee with dichloromethane is possible, the use of scCC>2 can be said to be natural Industrial applications of SCFs have been around for a long time. Decaffeination of coffee is perhaps the use that is best known [16], but of course the Born-Haber process for ammonia synthesis operates under supercritical conditions as does low density polyethylene (LDPE) synthesis which is carried out in supercritical ethene [17]. 

Several industrial processes use phase-transfer techniques with soluble catalysts, mostly for fine chemical productions (42,43). It is easy to believe that this technology will find a greater application in the near future, perhaps with the use of polymer-supported catalysts. 

In addition to large-scale industrial applications, solid acids, such as amorphous silica-alumina, zeolites, heteropoly acids, and sulfated zirconia, are also versatile catalysts in various hydrocarbon transformations. Zeolites are useful catalysts in fine-chemical production (Friedel-Crafts reactions, heterosubstitution).165-168 Heteropoly compounds have already found industrial application in Japan, for example, in the manufacture of butanols through the hydration of butenes.169 These are water tolerant, versatile solid-phase catalysts and may be used in both acidic and oxidation processes, and operate as bifunctional catalysts in combination with noble metals.158,170-174 Sulfated zirconia and its modified versions are promising candidates for industrial processes if the problem of deactivation/reactivation is solved.175-178... 

Despite the revolutionary advances achieved in the field of catalytic asymmetric synthesis, resolution methods both chemical and enzymatic are still probably the most used methods for preparation of optically pure organic compounds. This is especially true on large scale for the production of industrial fine chemicals. A very large number of chiral pharmaceuticals and pharmaceutical intermediates are manufactured by the process involving resolution. The reason behind the continued dominance of resolution in industrial production of optically pure fine chemicals is perhaps the reliability and scalability of these processes. 

To show how this complexity arises, let us consider the manufacture of a fictional, fine chemical product used in the pharmaceutical industry, called FCP1, by a multi-stage, batch process at a rate of 100 tonnes per year. 

The heterogeneous catalysts have a profound impact on the chemical industry in general for example 60% of all chemical processes, 75% of oil refining processes, nearly 100% of polymers and about one hundred petrochemicals depend on the action of catalysts, as well as a significant part of environmental technologies (VOCs, automotive emissions control, stationary sources, etc.) and fine chemical production. Actually, the worldwide catalysts market is worth about 10 billion USD, (i.e. 10 x 109 USD) a year and, according to some... 

It will be thus necessary to introduce a hierarchical approach. Lapkin et al. [65] have proposed four vertical hierarchy levels (i) product and process, (ii) company, (iii) infrastructure and (iv) society. Each level should reflect different boundary limits and use an appropriate choice of indicators. It is proposed also that the choice of appropriate indicators depends on the speciflcs of the industry sector and even on the types of products. The indicators should reflect speciflc by-products, wastes and emissions that are characteristic of the process or the product. Of course, alimit of the approach is how to make uniform the comparison between diflferent industrial sectors. On the other hand, we have already remarked that industrial chemical production is different from other manufacture industrial sectors, because (i) it includes very different types of productions, from several thousand tons per day in refinery to kg amounts per day in fine chemical production and (ii) it is characterized by a highly integrated structure in which a large part of the products are the input for other chemical processes. 

Catalysis, an important scientific and technological area for the development of environmentally friendly chemical processes, which m turn form the basis for cleaner industnal development and are also the key elements for an industrial prevention approach New, less polluting processes together with the optimization of existing processes depend to a great extent on the improvement of catalyst performance m the heavy and fine chemical production lines with a direct impact on the quality and quantity of by-products or waste generated... 

This switch from a chemical to an enzymatic process marks in the 1990s the beginning of biocatalysis on an industrial scale for the synthesis of fine chemicals. Similar processes were also developed for cephalosporin production. 

The drawbacks depend on the system scale. The reactor has to be loaded, unloaded, and cleaned, sometimes resulting in longer time than the reaction itself. The batch reactor requires less labor, however, requires special care to avoid contamination. Batch reactors are utilized in pharmaceutical industry, fine chemicals, natural products, and processes little known. 

In addition to large volume enzyme appHcations, there are a large number of specialty applications for the enzymes. These include use of the enzymes in clinical analytical applications, flavor production, protein modification, personal care products, DNA technology, and in fine chemical production. Unlike bulk industrial enzymes, these enzymes need to be free from side-activities, which require extensive purification process. 

Candidate process reactions for HEX-reactors should have the potential to be fast, produce or absorb heat (i.e. exothermic or endothermic) and form byproducts. Industrial examples include nitrations, polymerisations, hydrogenations, halogen-ations and aminations. Typically, such processes have byproduct outputs of rates between l-5kg/kg of desired products (in bulk chemicals), and 5-50kg/kg of product for fine chemicals. These processes provide the greatest opportunity for realising the benefits of HEX-reactors compared to stirred tank reactors. HEX-reactors of this type are usually derived from existing compact heat exchanger variants, e.g. the printed circuit reactor (PCR) and Chart-kote units. 

Adsorption process has been widely used in many chemical and related industries, such as the separation of hydrocarbon mixtures, the desulfurization of natural gas, and the removal of trace impurities in fine chemical production. Most of the adsorption researches in the past are focused on the experimental measurement of the breakthrough curve for studying the dynamics. The conventional model used for the adsorption process is based on one-dimensional or two-dimensional dispersion, in which the adsorbate flow is either simplified or computed by using computational fluid dynamics (CFD), and the distribution of adsorbate concentration is obtained by adding dispersion term to the adsorption equation with unknown turbulent mass dififusivity D(. Nevertheless, the usual way to find the D, is either by employing empirical correlation obtained from inert tracer experiment or by guessing a Schmidt number applied to the whole process. As stated in Chap. 3, such empirical method is unreliable and lacking theoretical basis. 

Catalysis and sustainable chemistry, for cleaner industrial production as process optimisation depend to a great extent upon the improvement of catalyst performance in bulk and fine chemical production. 

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