Catalysts in organic reactions

The exchange resins 6nd application in (i) the purification of water (cation-exchange resin to remove salts, followed by anion-exchange resin to remove free mineral acids and carbonic acid), (ii) removal of inorganic impurities from organic substances, (iii) in the partial separation of amino acids, and (iv) as catalysts in organic reactions (e.g., esterification. Section 111,102, and cyanoethylation. Section VI,22). 

A. U. Blackham md J. Palmer, Technetium as a Catalyst in Organic Reactions, AT945-1-2017, Atimtic Richfield Hmford Co., Richlmd, Wash., July 1967. 

Both pyridinium salts and pyridine A-oxides are of increased interest as chiral catalysts in organic reactions. Connon and Yamada independently designed and examined pyridinium salts as chiral catalysts in the acylation of secondary alcohols <06OBC2785 06JOC6872>. These two catalysts can be used for kinetic resolution of various sec-alcohols and uf/-diols in good to moderate enantiomeric excess. 

S / V CONTENTS Preface, Robert W. Hay. Structure and Function of Manganese-Containing Biomolecules, David C. Weather-bum. Repertories of Metal Ions as Lewis Acid Catalysts in Organic Reactions, Junghan Suh. The Multicopper-Enzyme Ascorbate Oxidase, Albrecht Messerschmidt. The Bioinorganic Chemistry of Aluminum, Tomas Kiss and Etelka Farkas. The Role of Nitric Oxide in Animal Physiology, Anthony R. Butler, Frederick Flitney and Peter Rhodes. Index. 

Uses. In preparation of fluxes component of enamels and glass catalyst in organic reaction... 

Beryllium chloride, an electron-deficient compound similar to aluminum chloride, is a Lewis acid. The anhydrous salt is used as a catalyst in organic reactions. Its applications, however, are limited. 

Cadmium fluoride is used in electronics and optics to produce crystals for lasers in the manufacture of phosphors and glass in high temperature dry-film lubricants and as a catalyst in organic reactions. 

The iodide salt is used as a source of dietary iodine in table salt and animal feed in cloud seeding as a coating in cathode ray tubes as a temperature indicator and as a catalyst in organic reactions. 

Mercury(II) sulfate is an electrolyte for primary batteries. Other apphca-tions are in extraction of gold and silver from roasted pyrites as a catalyst in organic reactions such as conversion of acetylene to acetaldehyde and as a reagent for wine coloring. 

Wilkinson s catalyst after its discoverer, G. Wilkinson. In 1973, the Nobel Prize in chemistry was awarded jointly to Wilkinson and E. O. H. Fischer for their respective contributions to the field of organometallic chemistry. As you will see in this and later chapters, compounds with carbon-metal bonds (organometallic compounds) are extremely useful reagents, reactive intermediates, or catalysts in organic reactions. To a very large extent, the work of Fischer and Wilkinson created the current interest and developments in the field of transition-metal organic chemistry, which will be discussed in Chapter 31. 

Resins are seldom used once and discarded. Whether the system is mn batchwise or in columns, the resin must be periodically removed from service and regenerated. An exception is the use of a resin as a catalyst in organic reactions. Each cycle consists of two principal steps, adsorption and regeneration, and one or more intermediate steps, rinse and backwash. Failure to use good practices results in poor cyclic performance. 

The Fischer indole synthesis itself is catalysed in this case by polyphosphoric acid (PPA), a sticky gum based on phosphoric acid (H3PO4) but dehydrated so that it contains some oligomers. It is often used as a catalyst in organic reactions and residues are easily removed in water. 

One of the most commonly used acid catalysts in organic reactions is p-toluensulfonic acid (PTSA). This acid was used to evaluate the possibility of selfcondensation of MAGME -polymers. Thick (20 ym) films were coated on glass plates and cured in an oven at different temperatures and curing times. Data in Table 2 show the time required at lowest possible curing temperature. In the case of PTSA it was difficult to achieve curing at temperatures below 120 C. This, and the fact that it took nearly... 

Common catalysts in organic reactions are acids and metals. Two examples are shown in the accompanying equations. 

Danishefsky and co-workers pioneered the use of chiral lanthanide complexes as catalysts in organic reactions. They found out that Eu(hfc)3, which is used as an NMR shift reagent, promoted hetero Diels-Alder reactions [30] of aldehydes with siloxydienes and induced enantiomeric enrichment (Sch. 1) [31]. Suitable substituents on the dienes were introduced to improve the extent of asymmetric induction. The best result was obtained in the reaction of benzaldehyde with l-methoxy-2-methyl-3-(trimethyl-siloxy)- , 3-butadiene using 1 mol % Eu(hfc)3 the enantiomerie excess was, however, moderate (58%). The authors maintained that the major advantage of lanthanide catalysis lay in the survival of otherwise labile systems used as adducts. 

Alcantara, A., Marinas, J. M., Sinisterra, J. V. Barium hydroxide as catalyst in organic reactions. VIII. Nature of the adsorbed species in Claisen-Schmidt reaction. React. Kinet. Catal. Lett. 1986, 32, 377-385. 

Use Intermediate in antifouhng paint agents catalyst in organic reactions. 

Use Catalyst in organic reactions, carbonyl iron for high-frequency coils. 

Sinisterra, J.V., Mouloungui, Z., Delmas, M., and Gaset, A., Barium hydroxide as catalyst in organic reactions. Part 5. Application in the Homer reaction under solid-liquid phase-transfer conditions. Synthesis, 1097, 1985. 

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