Oxygen of alkanes

Oxygenation of alkanes with hydrogen peroxide in homogeneous reactions can be obtained also with Keggin-type iron-substituted polyoxometalates. Evidence against radical reactions has been offered. 

Alkylated carboxonium ions have also been prepared by direct electrophilic oxygenations of alkanes, alcohols, and so on, by ozone or hydrogen peroxide in superacidic media606 [Eq. (3.82)]. 

Zeolite encapsulated complexes catalyse the oxygenation of alkanes with peroxides according to oxo chemistry, following a mechanism very similar to the oxygen-rebound mechanism encountered in monooxygenase enzymes. 

Hill and co-workers have reported that TMSP is effective for the epoxidation of alkenes and the oxygenation of alkanes by use of f-BuOOH and PhIO as oxidants [67]. The characteristics of TMSP in alkene epoxidation, compared with those of metalloporphy-rins, Schiff base complexes, and triflate salts, are as follows [67] ... 

N. Mizumo, C. Nozaki, 1. Kiyoto, M. Misono, Highly efficient utilization of hydrogen peroxide for selective oxygenation of alkanes catalyzed by Diiron-substituted polyoxometalate precursor, J. Am. Chem. Soc. 120 (1998) 9267. 

Recently, we have reported a simple method for the reductive activation of by applying an electrochemical O -Hj cell reaction for the oxygenation of alkanes and aromatics at the cathode [12-14]. With an acidic electrolyte in the Oj-Hj cell, the stoichiometric anode and cathode reactions are written simply as follows. 

Similar to the concept described for the Oj-Hj cell system, the reductive activation of oxygen can be expected at the cathode in the presence of a suitable catalyst. On the basis of this zinc-air battery model, we have designed a number of catalytic systems from mixtures of zinc powder, carboxylic acid and various metal chlorides for oxygenations of alkanes and alkenes. In these catalytic systems, zinc powder works as the reductant as well as the electron conducting medium. The carboxylic acid works as a proton-conducting medium. Oxygen is reductively activated on the metal cations by protons from the carboxylic acid and electrons from zinc powder. 

In addition to the oxidation of propane and propylene, the following mode of oxidation over bismuth-containing mixed catalysts has been reported (i) oxidative coupling of hydrocarbons, (ii) ammo-oxidation of toluene and xylenes, (iii) oxygenation of alkanes and alkenes, (iv) oxidation of alcohols, and (v) oxidative cleavage of carbohydrates. Representative results are summarized in Scheme 5.12. 

To mimic the Cytochrome P450 properties with MePc embedded in zeolites, the oxygenation of alkanes and cycloalkanes has been studied frequently. Occasionally, iodosobenzcnc (PhOI) has been used as oxidant [6] Alternatively, t-butyl hydroperoxide... 

Perhaps of more practical value is the oxygenation of alkanes, and a reaction catalyzed by VO(acac)2 is notable. ... 

N. Mizuno, M. Tateishi, T. Hirose, and M. Iwamoto, Chem. Lett., Oxygenation of Alkanes by... 

Selective Oxygenation of Alkanes Catalyzed by Diiron-Substituted Polyoxometalate Precursor, J. 

The controlled oxygenation of alkanes, alkenes, and aromatic hydrocarbons is one of the most important technologies for the conversion of crude oil and natural gas to valuable commodity chemicals. Biomimetic studies of metalloporpltyrins have led to important advances in practical catalysis, especially with ruthenium porphyrins. Reaction of wj-CPBA, periodate, or iodosylbenzene with Ru(II)(TMP)(CO) produced RuCVIjfTMPXOjj . Remarkably, Ru(VI)(TMP)(0)2 was found to catalyze the aerobic epoxidation of olefins under mild conditions. Thus, for a number of olefins including cyclooctene, norbomene, cis-, and trans- -methyl styrene 16-45 equivalents of epoxide were... 

Grinstaff, M.W., M.G. Hill, J.A. Labinger, and H.B. Gray (1994). Mechanism of catalytic oxygenation of alkanes by halogenated iron porphyrins. Science 264, 1311. 

Scheme IX.8, The mechanism proposed for the FeCli-photocatalyzed oxygenation of alkanes, RH, into alkyl hydroperoxides, ROOH. 

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