Manganese catalysis oxidation

Heterc eneous catalysis can be demonstrated in the laboratory by adding a small amount of manganese(iv) oxide, Mn02, to a dilute solution of hydrogen peroxide (Chapter 6). 

Scheme 7.48 Domino oxidation-Michael reaction catalysed by chiral amine catalysis and manganese catalysis.

The manganese(iii) oxidation of methanoP has been reported. The reaction, which takes place via an inner-sphere mechanism, is first order in both oxidant and substrate. The effects of other cations have been examined, catalysis by cobalt(n) and aluminium(iii) being exhibited with retardation of the reaction specific to manganese(n). Inner-sphere complexes have also been detected in the corresponding reaction with pinacol in acidic perchlorate media. The oxidation of a-hydroxyisobutyric acid, however,... 

Heterogeneous catalysis occurs when the catalyst is in a different phase to the reaction mixture. For example, the decomposition of aqueous hydrogen peroxide catalysed by manganese(IV) oxide. 

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 oxidation of tartaric and glycollic acid by chromic acid also induces the oxidation of manganous ions. In the presence of higher concentrations of manganese(II) the rate of oxidation of the acids is diminished to about one-third of that in the absence of manganous ions. The decrease of the rate has been attributed to manganese(II) catalysis of the disproportionation of the intermediate valence states of chromium probably chromium(IV). 

Kumar, R., Sithambaram, S. and Suib,S.L. (2009) Cyclohexane oxidation catalyzed by manganese oxide octahedral molecular sieves - effect of acidity of the catalyst. Journal of Catalysis, 262,304—313. Sithambaram, S., Kumar, R., Son, Y. and Suib, S.L. (2008) Tandem catalysis direct catalytic synthesis of imines from alcohols using manganese octahedral molecular sieves. Journal of Catalysis, 253, 269-277. 

Iyer, A., Galindo, H., Sithambaram, S., King ondu, C., Chen, C. and Suib, S.L. (2010) Nanoscale manganese oxideoctahedral molecular sieves (OMS-2) as efficient photocatalysts in 2-propanol oxidation. Applied Catalysis A General, 375, 295-302. 

The violent decomposition observed on adding charcoal to cone, hydrogen peroxide is mainly owing to catalysis by metallic impurities present and the active surface of the charcoal, rather than to direct oxidation of the carbon [1], Charcoal mixed with a trace of manganese dioxide ignites immediately on contact with cone, peroxide [2],... 

Kim, H.-S., Pasten, P.A., Gaillard, J.-F. and Slair, P.C. (2003) Nanocrystalline todorokite-like manganese oxide produced by bacterial catalysis. Journal of the American Chemical Society, 125, 14284-14285. 

Bezemer, G. L., Radstake, P. B., Falke, U., Oosterbeek, H., Kuipers, H. P. C. E., van Dillen, A., and de Jong, K. P. 2006. Investigation of promoter effects of manganese oxide on carbon nanofiber-supported cobalt catalysts for Fischer-Tropsch synthesis. Journal of Catalysis 237 152-61. 

The reaction of olefin epoxidation by peracids was discovered by Prilezhaev [235]. The first observation concerning catalytic olefin epoxidation was made in 1950 by Hawkins [236]. He discovered oxide formation from cyclohexene and 1-octane during the decomposition of cumyl hydroperoxide in the medium of these hydrocarbons in the presence of vanadium pentaoxide. From 1963 to 1965, the Halcon Co. developed and patented the process of preparation of propylene oxide and styrene from propylene and ethylbenzene in which the key stage is the catalytic epoxidation of propylene by ethylbenzene hydroperoxide [237,238]. In 1965, Indictor and Brill [239] published studies on the epoxidation of several olefins by 1,1-dimethylethyl hydroperoxide catalyzed by acetylacetonates of several metals. They observed the high yield of oxide (close to 100% with respect to hydroperoxide) for catalysis by molybdenum, vanadium, and chromium acetylacetonates. The low yield of oxide (15-28%) was observed in the case of catalysis by manganese, cobalt, iron, and copper acetylacetonates. The further studies showed that molybdenum, vanadium, and... 

Square Concentration Pulses in Oxidation Catalysis over Perovskite-type Oxides of Manganese and Iron... 

A method was proposed for the preparation of p-hydroxybenzoic acid by oxidation of p-cresol with atmospheric oxygen in an acetic acid-acetic anhydride mixture under catalysis of cobalt acetate, manganese(II) acetate, and sodium bromide (Litvintsev et al. 1994). This procedure ensures 60% yield of p-acetoxybenzoic acid and 100% conversion of the initial p-cresol. 

DMT can be made from crude TA or from />-xylene directly. Esterification of TA with methanol occurs under sulfiiric acid catalysis. Direct oxidation of /7-xylene with methanol present utilizes copper and manganese salt catalysis. 

In chemical industries, manganese is used to prepare several compounds. It also is used as a catalyst. Its salts have numerous apphcations in oxidation, catalysis, and medicine. 

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