Manganese-containing catalysts

The oxidation of saturated hydrocarbons in the presence of iron- or manganese-containing catalysts can be achieved by using a variety of oxidants including alkyl hydroperoxides, peroxycarboxylic acids, iodosyl-benzene, dihydrogen peroxide, and dioxygen (9-11). It has been shown that chiral iron- and manganese-porphyrin complexes catalyze the asymmetric epoxidation of unfunctionalized alkenes (75). Except for a number of experiments in which up to 96 % enantiomeric excess (ee) has been reported (16,17), in most epoxidation reactions with chiral porphyrins only a low to moderate enantiomeric excess of the product is obtained (18,19). In association with these catalysts, alkyl hydroperoxides and iodosylbenzene are often used as primary oxidants (18,19). 

Other hand, the higher surface oxygen concentration was found to be preferable for SCR reactions over manganese-containing catalysts because higher surface oxygen concentration facilitates the —NH2 formation [69], and the formed —NH2 species would then react with gas-phase NO or nitrite intermediates on the catalysts surface to form nitrogen and water. 

Manganese-containing catalysts, namely, the samples prepared by thermal degradation in air, were tested in the oxidation H2 with O2 as a model reaction for the catalytic combustion of H2-containing gas mixtures. The conversion of H2 to H2O increases with temperature for all catalysts studied. 

Light naphtha containing hydrocarbons in the C5-C7 range is the preferred feedstock in Europe for producing acetic acid by oxidation. Similar to the catalytic oxidation of n-butane, the oxidation of light naphtha is performed at approximately the same temperature and pressure ranges (170-200°C and =50 atmospheres) in the presence of manganese acetate catalyst. The yield of acetic acid is approximately 40 wt%. 

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. 

By the simple procedure of passing dispersed air through a suspension of ff2-diethylbenzene, 1% chromia, and 4% calcium carbonate at 130° for 40 hours, a 50% yield of m-ethylacetophenone is obtained. Likewise, aromatic esters, acetophenones, and halogenated benzenes containing alkyl groups yield the corresponding keto esters, diketones, and halo ketones, respectively. Manganese dioxide catalyst has also been used. Tetralin can be oxidized to a-tetralone with dispersed air in the absence of a catalyst (56%). ... 

Raja R, Thomas JM (1998) A manganese containing molecular sieve catalyst designed for the terminal oxidation of dodecane in air. Chem Commun 1841... 

In addition to hydroperoxide decomposition and peroxy-radical reduction, manganese-ion catalysts have a pronounced tendency to promote the rapid oxidation of carbonyl-containing intermediates via enol mechanisms [49, 52-56] ... 

The prospect of public correction by Nernst was intolerable. Haber leaped into action, repeating his experiments in more elaborate fashion, employing different sizes of reaction containers and different materials—iron, nickel, chromium, and manganese—as catalysts to speed the reaction along. His new results still didn t agree with those of Nernst, though they were closer. 

R. Neumann, M. Gara, The Manganese-containing polyoxometalate, [WZnMnn2(ZnW9O34)2]12-, as a remarkably effective catalyst for hydrogen peroxide mediated oxidations, J. Am. Chem. Soc. 117 (1995) 5066. 

Catalyst 236 is by no means the only one to achieve such results. Helmchen56 uses the manganese-containing monophosphine 245 for alkylation of malonates with racemic allylic chloride 246 to give the adduct 247 that is used in the synthesis of the lactone 248. 

Catalytic combustors containing palladium and manganese for gas turbines JP 10047610 Mitsubishi Heavy Industries Ltd. Pd-containing catalyst as an initial stage followed by Mn-containing catalyst with magnetoplumbite structure... 

Breslow synthesized manganese-containing porphyrins 65 and 66, which selectively catalyzed epoxidation of unsaturated compounds and the benzyl position of C-H bonds in hydrocarbons containing two phenyl groups and steroids owing to the orientation of the substrate in its binding to the catalyst. The activity was maximum for a substrate corresponding to the distance between cyclodextrins in the complex [199-201]. 

Neumann, R., and G. Mohammad, Highly Active Manganese-Containing Polyoxomet-alate as Catalyst for Epoxidation of Alkenes with Hydrogen Peroxide, J. Am. Chem. Soc. 116 5509-5510 (1994). 

Kiylov et aZ. studied the catalytic reaction of methane with carbon dioxide over MnO -containing catalysts for syngas production. The effect of the modification of nickel by different additives, such as copper, chromium, iron and manganese oxides, was evaluated and the best effect was obtained with manganese oxide an increase of manganese content originated an increase of the carbon dioxide conversion and a decrease of coke formation. 

The oxidative -destructive transformations, the liquid-phase oxidation of olefins, the oxidizing and catalytic destructions proceed in accordance with chain radical mechanism with origin of chains with the participation of the catalyst. One of variants of the latter is the reaction between the manganese-containing heterogeneous catalyst and olefins, having trailer double bond [1] ... 

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