Homogeneous catalysis industrial applications

In this section, we describe selected homogeneous catalytic processes that are of industrial importance. Many more processes are applied in industry and detailed accounts can be found in the suggested reading at the end of the chapter. Two advantages of homogeneous over heterogeneous catalysis are the relatively mild conditions under which many processes operate, and the selectivity that can be achieved. A disadvantage is the need to separate the catalyst at the end of a reaction in order to recycle it, e.g. in the 

Throughout this section, the role of coordinatively unsaturated 16-electron species (see Section 24.7) and the ability of the metal centre to change coordination number (essential requirements of an active catalyst) should be noted. 

Although this example of the catalytic conversion of N2 to NH3 under ambient conditions in a well-defined molecular system remains at the research stage, it establishes that such conversions are possible. 

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Gould, R. F., Editor, Homogeneous Catalysis Industrial Applications and Implications, ACS Adv. in Chem., 70, Washington, 1968. 

T he six years since the first Advances in Chemistry Series volume, Homogeneous Catalysis—Industrial Applications and Implications, (Number 70) have been a period of mushrooming activity in the field. Not only has this activity been marked by the discovery of new types of catalysts and new insights into reaction mechanisms, but several major commercial processes based on homogeneous catalysts have been developed. 

In contrast to heterogeneous catalysis, industrial applications of homogeneous catalysis are relatively scarce, largely being restricted to the speciality and pharmaceutical sectors. Homogeneous catalysts have been well researched, since their catalytic centres can be relatively easily... 

Analytical Chemistry Batteries Catalysis, Homogeneous Catalysis, Industrial Electrochemical Engineering Isotopes, Separation AND Applications Metallogeny Mining Engineering Organometallic Chemistry Periodic Table (Chemistry) Photographic Processes and materials... 

A concise summary of chemistry of technologically important reactions catalysed by organometallic complexes in solution. Cornils B and Herrmann W A (eds) 1996 Applied Homogeneous Catalysis with Organometallio Compounds (Weinheim VCH) A two-volume, multiauthored account with emphasis on industrial applications. 

Homogeneous catalysis by lin compounds is also of great indusirial importance. The use of SnCU as a Friedel-Crafts catalyst for homogeneous acylation, alkylation and cyclizaiion reactions has been known for many decades. The most commonly used industrial homogeneous tin catalysis, however, are the Sn(ll) salts of organic acids (e.g. acetate, oxalate, oleale, stearate and ocToate) for the curing of silicone elasloniers and, more importantly, for the production of polyurethane foams. World consumption of tin catalysts for the.se Iasi applications alone is over 1000 tonnes pa. 

Cornils B (1999) Modern Solvent Systems in Industrial Homogeneous Catalysis.206 133-152 Crooks RM, Lemon III BI, Yeung LK, Zhao M (2001) Dendrimer-Encapsulated Metals and Semiconductors Synthesis, Characterization, and Applications. 212 81 -135 Croteau R, see Davis EM (2000) 209 53 - 95 CurranDP, see Maul JJ (1999) 206 79-105... 

The conversion of ethylene to acetaldehyde using a soluble palladium complex, developed in the late 1950s, was one of the early applications of homogeneous catalysis and the first organo-palladium reaction practised on an industrial scale [40], Typically this reaction requires stoichiometric amounts of CuCl under aerobic conditions. The use of copper represents not only an environmental issue, but often limits the scope of ligands that can be used in conjunction with Pd. 

Regioselective reactions belong to the most important applications of homogeneous catalysis. An example is the hydroformylation of alkenes, which is a very important industrial reaction ... 

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. 

The hydroformylation of alkenes, which was originally discovered by Otto Roelen in 1938 [1], has developed into one of the most important applications of homogeneous catalysis in industry (Scheme 1) [2,3]. Today, more than 9 million tons of so-called oxo-products are produced per year, a number which is still rising continuously. The majority of these oxo-products stem... 

Bhaduri, S., and Mukesh, D. (2000). Homogeneous Catalysis Mechanisms and Industrial Applications. Wiley-Interscience, New York. 

This achievement was unique in two respects 1) it was the first example of industrial application of a homogeneous enantioselective catalysis methodology and 2) it represented a rare example of very quick convergence of basic knowledge into commercial application. The monophosphine ligand CAMP was shortly replaced by the related diphosphine ligand DIPAMP which improved the selectivity for the I-DOPA system up to 95% ee [45]. 

A. F. Noels, A.J. Hubert. In A. Mon-treux, F. Petit (Eds.), Industrial Applications of Homogeneous Catalysis. Riedel Publishing Company, Dordrecht, Netherlands, 1988. 

The cost of the catalysts represents a major hurdle on the road to the industrial application of homogeneous catalysis, and in particular for the production of fine chemicals [1, 2], This is particularly true for chiral catalysts that are based on expensive metals, such as rhodium, iridium, ruthenium and palladium, and on chiral ligands that are prepared by lengthy total syntheses, which often makes them more expensive than the metals. In spite of this, the number of large-scale applications for these catalysts is growing. Clearly, these can only be economic if the substrate catalyst ratio (SCR) can be very high, often between 103 and 105. 

Optically active aldehydes are important precursors for biologically active compounds, and much effort has been applied to their asymmetric synthesis. Asymmetric hydroformylation has attracted much attention as a potential route to enantiomerically pure aldehyde because this method starts from inexpensive olefins and synthesis gas (CO/H2). Although rhodium-catalyzed hydrogenation has been one of the most important applications of homogeneous catalysis in industry, rhodium-mediated hydroformylation has also been extensively studied as a route to aldehydes. 

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