Catalysis in oxidations

Iron catalysis in oxidation reactions with peroxides, both hydrogen peroxide and alkyl hydroperoxides, is frequently regarded as just a Haber-Weiss-type system where hydroxyl... 

Bortolini, O., Conte, V., Di Furia, F. and Modena, G. (1986) Metal catalysis in oxidation by peroxides. Part 25. Molybdenum- and tungsten-catalyzed oxidations of alcohols by diluted hydrogen peroxide under phase-transfer conditions. /. Org. Chem., 51, 2661. Barak, G. and Sasson, Y. (1989) Effect of phase-transfer catalysis on the selectivity of hydrogen peroxide oxidation of aniline. /. Org. Chem., 54, 3484. 

Horvath O, Stevenson KL (1992) Charge transfer photochemistry of coordination compounds. Weinheim, VCH Ikawa M, Snell EE (1954) Metal ion catalysis in oxidative transaminations by pyiidoxal phosphate. J Amer Chem Soc 76 4900-4905... 

Robert A.W. Johnstone, Ph.D., is a full professor in the Department of Chemistry at the University of Liverpool, Liverpool, U.K. He possesses a D.Sc., a Ph.D., and a B.Sc. in chemistry. He is also a Fellow of The Royal Society of Chemistry (FRSC). An author and contributor to several books. Dr. Johnstone has published over 200 journal papers in natural product chemistry, catalysis in oxidation and reduction, and spectroscopy. His work has resulted in several new synthetic procedures in organic chemistry that are widely used and have provided some 30 full patents. Part of his research with industry led to a Queen s Award for Technological Achievement, an award not usually given to industrial and business enterprises and not normally given to university staff. The award concerned large-scale manufacture of an important ingredient of timber preservative by a new catalytic method, which produces about 30001 per annum of the product. Apart from his career... 

Asymmetric catalysis in oxidation reactions by molecular oxygen with a chiral cobalt catalyst was studied by Shibata et al. in 1931 for the kinetic resolution... 

Voorhoeve RJH, Remeika JP, Trimble LE. (1976). Defect Chemistry and Catalysis in Oxidation and Reduction over Perovskite-Type Oiddes. Ann Ny AcadSci. 272, 3-21. 

In contrast to oxidation in water, it has been found that 1-alkenes are directly oxidized with molecular oxygen in anhydrous, aprotic solvents, when a catalyst system of PdCl2(MeCN)2 and CuCl is used together with HMPA. In the absence of HMPA, no reaction takes place(100]. In the oxidation of 1-decene, the Oj uptake correlates with the amount of 2-decanone formed, and up to 0.5 mol of O2 is consumed for the production of 1 mol of the ketone. This result shows that both O atoms of molecular oxygen are incorporated into the product, and a bimetallic Pd(II) hydroperoxide coupled with a Cu salt is involved in oxidation of this type, and that the well known redox catalysis of PdXi and CuX is not always operalive[10 ]. The oxidation under anhydrous conditions is unique in terms of the regioselective formation of aldehyde 59 from X-allyl-A -methylbenzamide (58), whereas the use of aqueous DME results in the predominant formation of the methyl ketone 60. Similar results are obtained with allylic acetates and allylic carbonates[102]. The complete reversal of the regioselectivity in PdCli-catalyzed oxidation of alkenes is remarkable. 

Oxidation Catalysis. The multiple oxidation states available in molybdenum oxide species make these exceUent catalysts in oxidation reactions. The oxidation of methanol (qv) to formaldehyde (qv) is generally carried out commercially on mixed ferric molybdate—molybdenum trioxide catalysts. The oxidation of propylene (qv) to acrolein (77) and the ammoxidation of propylene to acrylonitrile (qv) (78) are each carried out over bismuth—molybdenum oxide catalyst systems. The latter (Sohio) process produces in excess of 3.6 x 10 t/yr of acrylonitrile, which finds use in the production of fibers (qv), elastomers (qv), and water-soluble polymers. 

Transition metal catalysis in Baeyer-Villiger oxidation of cyclic ketones with formation of lactones 98AG(E)1198. 

Solid oxide fuel cell, SOFC anodes, 97 catalysis in, 98,410 cathodes, 96... 

O2, Mn, pH, and solid concentrations indicates that the character of the solid is important partly because some surfaces bind Mn " more strongly and partly because they facilitate the electron transfer differently. Catalysis by enzymes is clearly the most effective oxidation enhancing process as indicated by the laboratory studies with spores and material from the O2/H2S interface of Saanich Inlet. Microbial catalysis in this environment reduces the oxidation lifetime of Mn to about one day. This example illustrates... 

Table 1. Phase transfer catalysis in alkylaromatic oxidation. 

Sulfides play an important role in hydrotreating catalysis. Whereas oxides are ionic structures, in which cations and anions preferably surround each other to minimize the repulsion between ions of the same charge, sulfides have largely covalent bonds as a consequence there is no repulsion which prevents sulfur atoms forming mutual bonds and hence the crystal structures of sulfides differ, in general, greatly from those of oxides. 

Early work of Dhar established that oxidation of oxalic acid by chromic acid occurs readily, but some of his kinetic data are unreliable as the substrate itself acted as the source of hydrogen ions. The reaction is first-order in oxidant and is subject to strong manganous ion catalysis (as opposed to the customary retardation), the catalysed reaction being zero-order in chromic acid. This observation is related to those found in the manganous-ion catalysed oxidations of several organic compounds discussed at the end of this section. 

Pollock RJ, LB Hersh (1973) A-methylglutamate synthetase. The use of flavin mononucleotide in oxidative catalysis. J Biol Chem 248 6724-6733. 

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