Industrial chemical processes

Solid Superacids. Most large-scale petrochemical and chemical industrial processes ate preferably done, whenever possible, over soHd catalysts. SoHd acid systems have been developed with considerably higher acidity than those of acidic oxides. Graphite-intercalated AlCl is an effective sohd Friedel-Crafts catalyst but loses catalytic activity because of partial hydrolysis and leaching of the Lewis acid halide from the graphite. Aluminum chloride can also be complexed to sulfonate polystyrene resins but again the stabiUty of the catalyst is limited. 

The Crignard reactant having a long alkyl chain was added to a keto compound the substituents remain undisclosed [134]. Thereby, an enolate is formed which is further reacted in the framework of a multi-stage fine-chemical industrial process. 

IARC. 1982. IARC monographs on the evaluation of the carcinogenic risk of chemicals to humans. Chemicals, industrial processes and industries associated with cancer in humans. IARC monographs, Volumes 1 to 29, supplement 4. International Agency for Research on Cancer, Lyon, France. 

In the chemical industry processes are often capital intensive with consistent raw materials being converted into long-life products. If a process is capital intensive it pays to run the process 24 hours a day, 7 days a week, 52 weeks a year, as far as technically possible. Labour costs are likely to be minimised by working continuously as well. 

Supplement No. 4 Chemicals, Industrial Processes and Industries Associated with Cancer in Humans lARC Monographs, Volumes 1 to 29) 1982 292 pages (out-of-print)... 

Humans, Supplement 4, Chemicals, Industrial Processes and Industries Associated with... 

In the pharmaceutical and fine chemical industries, process development and optimisation start when the target chemical structure and a possible synthetic path have been identified by chemical research. Chemical process development ends when the production has been successfully implemented in the final production facility. 

O chemical plant the reaction vessels and equipment for manufacturing chemicals O feedstock starting materials for chemical industrial processes O brine a concentrated solution of sodium chloride O Haber process the industrial process for the manufacture of ammonia O Contact process the industrial process for the manufacture of sulfuric aod... 

Catalysis refers to the phenomenon by which the rate of a chemical reaction is accelerated by a snbstance (the catalyst) not appreciably consnmed in the process. The term catalysis was coined by Berzelins in 1835 and scientifically defined by Ostwald in 1895, but applications based on catalysis can be traced back to thousands of years ago with the discovery of fermentation to produce wine and beer. Nowadays, catalysts are used in 80% of all chemical industrial processes, and create annual global sales of about 1500 billion dollars and contribute directly or indirectly to approximately 35% of the world s GDP. Catalysis is central to a myriad of applications, including the manufacture of commodity, fine, specialty, petro-, and agro- chemicals as well as the production of pharmaceuticals, cosmetics, foods, and polymers. Catalysis is also an important component in new processes for the generation of clean energy, and in the protection of the enviromnent both by abating environmental pollutants and by providing alternative cleaner chemical synthetic procedures. 

Solid or supported catalysts are preferred in petrochemical and chemical industrial processes. Hence, solid superacid catalysts are of substantial interest. Acidic oxides, discussed earlier, are used extensively however, their relatively low acidity necessitates higher operating temperatures. Even at higher temperatures, they are inefficient in promoting such reactions as the transethylation of benzene with di- and polyethylbenzenes. Consequently, new solid acid systems have been developed with considerably higher... 

As pointed out before, in the USA and UK green chemistry has become synonymous with chemical industrial processes that avoid (toxic) by-products as much as possible the greening of industry. The following sections analyze in more detail the principles and some examples of this green chemistry. In many countries, concepts such as green accounts, green procurement and green taxes are accepted. 

The environmental impact of the cyclohexane oxidation could also be reduced. An alternative is to start from benzene and make a selective hydrogenation to form cyclohexene. Ru-based supported catalysts working in the liquid phase and in the presence of a co-catalysts such as Zn (Asahi Chemical Industry process) are selective in the reaction, with yields up to about 60% [247], but with cyclohexane as the main by-product. Cyclohexene is hydrated in the liquid phase with an MFI zeolite as catalyst at moderate temperature (100-130 °C). This reaction is very selective (>99%). This route was primarily developed for the synthesis of adipic acid, but could be used also to reduce the number of products and separation costs in the production of cyclohexanone. 

We thus conclude this chapter by indicating that the intense research on catalysis in the last decade, although apparently of limited success in developing new industrial applications, has instead provided the background for breakthrough new applications in all areas of sustainable chemical industrial processes. 

Applicability to Evaluating the Sustainability of Chemical Industrial Processes... 

We may further add that, in the chemical industry, process improvement results in a significant reduction of waste, even if this aspect does not appear, at least in a transparent way, in the cited indicators. 

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