Manganese catalyst

Reactions 33 and 35 constitute the two principal reactions of alkyl hydroperoxides with metal complexes and are the most common pathway for catalysis of LPOs (2). Both manganese and cobalt are especially effective in these reactions. There is extensive evidence that the oxidation of intermediate ketones is enhanced by a manganese catalyst, probably through an enol mechanism (34,96,183—185). 

The typical SEA process uses a manganese catalyst with a potassium promoter (for solubilization) in a batch reactor. A manganese catalyst increases the relative rate of attack on carbonyl intermediates. Low conversions are followed by recovery and recycle of complex intermediate streams. Acid recovery and purification involve extraction with caustic and heat treatment to further decrease small amounts of impurities (particularly carbonyls). The fatty acids are recovered by freeing with sulfuric acid and, hence, sodium sulfate is a by-product. 

Sodium hexakis(formato)molybdate, 3, 1235 Sodium hypochlorite alkene epoxidation manganese catalysts, 6,378 Sodium ions biology, 6, 559 selective binding biology, 6, 551 Sodium molybdate, 3, 1230 Sodium peroxoborate, 3,101 Sodium/potassium ATPase, 6, 555 vanadate inhibition, 3, 567 Sodium pump, 6, 555 mechanism, 6, 556 Sodium pyroantimonate, 3, 265 Sodium salts... 

In the late 1950 s two groups - one at ICI (ref. 1) and the other at the Mid-Century Corporation (ref. 2) - independently discovered that p-xylene is oxidized to terephthalic acid in almost quantitative yield when soluble bromides are used together with cobalt and manganese catalysts in acetic acid solvent at temperatures > 130 °C (ref. 3). This discovery formed the basis for what became known as the Mid-Century process and later, when the Mid-Century Corporation was acquired by Amoco, as the Amoco MC process for the commercial production of terephthalic acid. A large part of the ca. 6 million tons of the latter that are manufactured annually, on a worldwide basis, are produced via this method. This makes it the most important catalytic oxidation process (ref. 4). 

Kantcheva, M. (2001) Identification, Stability, and Reactivity of NO, Species Adsorbed on Titania-Supported Manganese Catalysts, J. Catal., 204, 479. 

In a factory manufacturing organo-iron and organo-manganese catalysts, use of cotton waste to mop up a spill of dilute hydrazine solution led to a spontaneous fire later. The fire was attributed to onset of rapid metal-catalysed decomposition of the hydrazine after sufficient water had evaporated from the waste, the traces of heavy metals originating from dust contamination, etc. 

Ming, J., Koizumi, N., Ozaki, T., and Yamada, M. 2001. Adsorption properties of cobalt and cobalt-manganese catalysts studied by in-situ diffuse reflectance FTIR using CO and CO+H2 as probes. Appl. Catal. A Gen. 209 59-70. 

Asymmetric amidation of sp C—H bonds was reported in good yields and moderate enantioselectivities (Scheme 5.27)." ° When benzylic or allylic C—H bonds were used, similar results were also obtained." In these reactions the prepared nitrenes, PhI=NTs, and/or PhI(OAc)2+NH2Ts were used as nitrogen atom transfer sources. The studies showed that Ru=NTs was formed in situ and acted as a possible active intermediate when a ruthenium catalyst was used (Figure 5.12), whereas a radical intermediate might be involved when a manganese catalyst was used. 

These PVP polymers provide a "proximal effect" without addition of free pyridine in the reaction mixture. Different studies have shown that only one pyridine per manganese catalyst is sufficient to enhance the rate of the catalytic oxygen atom transfer from the high-valent metal-oxo species to the organic substrate. The advantage of PVP polymer over a cationic Amberlite resin (see Scheme II for structures) have been recently illustrated in the modeling of ligninase (11). 

Kinetic Studies. Peracetic Ac id Decomposition. Studies with manganese catalyst were conducted by the capacity-flow method described by Caldin (9). The reactor consisted of a glass tube (5 inches long X 2 inches o.d.), a small centrifugal pump (for stirring by circulation), and a coil for temperature control (usually 1°C.) total liquid volume was 550 ml. Standardized peracetic acid solutions in acetic acid (0.1-0.4M) and catalyst solutions also in acetic acid were metered into the reactor with separate positive displacement pumps. Samples were quenched with aqueous potassium iodide. The liberated iodine was titrated with thiosulfate. Peracetic acid decomposition rates were calculated from the feed rate and the difference between peracetic acid concentration in the feed and exit streams. 

Temperature, °C. Cobalt Catalyst kj, liters mole 1 min. 1 Manganese Catalyst k2, liters2 mole 9 min. ... 

Cumene oxidized relatively slowly, at about 1/13 the rate of p-xylene. This was not caused by the formation of phenol, as might be expected by an acid-catalyzed rearrangement of cumene hydroperoxide. No phenol or product clearly derived from phenol, as by radical attack or by oxidation to a quinone, was detected at any time in the reaction mixture. The two major products were a-methylstyrene and 2-phenylpropylene oxide their concentrations increased with time. The group at Shell also observed the formation of a-methylstyrene and 2-phenylpropylene oxide among the products of cumene oxidation in butyric acid at 140°C. with cobalt and manganese catalysts (30). 

Together with his colleagues in the laboratory he studied problems of the crystallization of nitroglycerin, oxidation of hydrogen on a platinum catalyst, and oxidation of CO on manganese catalysts. The first and the third problems were of practical significance. 

Manganese(III) acetate is poorly reactive with saturated hydrocarbons.514 However, oxidation of adamantane by Mn(OAc)3 in trifluoroacetic acid gives relatively high yields of 1-adamantyl trifluoroacetate, showing a preferential attack at tertiary C—H bonds.515 Oxidation of n-alkanes by air in the presence of manganese catalysts constitutes the basis for an industrial process for the manufacture of synthetic fatty acids from n-alkanes of petroleum origin, which has been commercially developed in the Soviet Union.516... 

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