Industrial Perspectives on the Use of Dioxygen (D. Riley et al.). Metal Phosphates (A. Johnstone et al.). Electropox (T.J. Mazanec). Kinetics of Reaction of Dioxygen with Lithium Nickel Oxide, and the Role of Surface Oxygen in Oxidative Coupling of Methane (Y.K. Sun et al.). Oxidation of Olefins to Aldehydes Using a PalladiumCopper Catalyst (T.T. Wenzel). New Metal Complex Oxygen Absorbents for the Recovery of Oxygen (D. Ramprasad et al.). Oxygenation of Olefins with Molecular Oxygen Catalyzed by Low Valent Metal Complexes (T. Mukaiyama). Formation and Alkene Epoxidation by HigherValent OxoMetalloporphyrins (R.D. Arasasingham, T.C. Bruice). Bioinspired Catalysis (J.E. Bond et al.). Studies on the Mechanisms of Gif Reactions (G. Balavoine et al.). Catalytic Chemistry of Cytochrome P450 and Peroxidases (P.R. Ortiz de Montellano). Methane Monoxygenases (K.E. Liu et al.). 66 additional articles. Index.

The Activation of Dioxygen and Homogeneous Catalytic Oxidation

Cerium(IV) Ammonium Nitrate as a Catalyst in Organic Synthesis

4.11 – Polyoxometalates: Reactivity

A study on the oxidation of phenol by heterogeneous iron silica catalyst

The oxidation of ethylbenzene with hydrogen peroxide and molecular oxygen catalyzed by cobalt and bromide ions in acetic acid as solvent was studied. The oxidation of ethylbenzene with hydrogen peroxide provided a mixture of ethylbenzene hydroperoxide, acetophenone, 1-phenylethanol, and 1-phenylethyl acetate. After rapid initial oxidation, the reaction rate decreased steadily so that full conversion of ethylbenzene and reaction intermediates to acetophenone could not be achieved. In contrast, no catalyst deactivation was observed for oxidations using atmospheric oxygen. Ethylbenzene was oxidized to acetophenone in 74% selectivity after a reaction time of 150 min at 80 °C. The reaction conditions were translated to a continuous flow process using a tubular gas–liquid reactor. At temperatures of 110 to 120 °C and an oxygen pressure of ∼12 bar, the reaction time necessary for complete oxidation of ethylbenzene was reduced to 6 to 7 min. The acetophenone was formed in 80 to 84% selectivity, and virtually pure...

Homogeneous Liquid-Phase Oxidation of Ethylbenzene to Acetophenone in Continuous Flow Mode

Alkenes can be epoxidised with hydrogen peroxide using a homogeneous heavy metal catalyst, but discharge of spent reaction mixtures releases the heavy metal in the environment. The problem can be ameliorated by selecting a heterogeneous catalyst system comprising a tungsten-containing heteropolyacid supported on selected Group IIa, IIb, IIIb, IVa or IVb inorganic supports or on a strong basic resin, which catalyst has either been calcined after impregnation or in the impregnation stage an alcoholic solution of the heteropolyacid is employed and by employing a nitrilo or oxygenated polar solvent reaction medium. A number of preferred heteropolyacids satisfy the empirical formula M3/nPWwMO12-wO40 in which w represents an integer of at least 1, M represents a counterion and n its basicity. Preferred supports include activated alumina, calcined at 400 to 600° C and cross-linked quaternary ammonium-substituted polystyrene resins. The most preferred catalysts are made by impregnating an inorganic support with a methanol solution of the heteropolyacid to a desired loading of active material on the support and subsequently calcining the loaded support at 400 to 600° C. Preferred reaction media include acetonitrile and tertiary butanol.

Epoxidation using hydrogen peroxide and tungsten catalysts

4- t -Butyltoluene can be oxidised in acetic acid to 4- t -butylbenzaldehyde by hydrogen peroxide in a process catalyzed by cerium(III) and bromide ions. The conversion proceeds via benzylic bromination, hydrolysis of the bromide to alcohol and the rapid oxidation of the alcohol to the aldehyde by bromine. The reaction is ineffective in the absence of bromide but is also inhibited by significant quantities of the ion, apparently because the hydrolysis step is reversible. The role of the cerium has not been clearly established. Cerium(IV) is formed in the system but the first step appears not to involve electron transfer from the aromatic ring. Nor can simple radical bromination explain the rate of formation of benzylic bromide.

The selective oxidation of toluenes to benzaldehydes by cerium(III), hydrogen peroxide and bromide ion

A process for the oxidation of organosulphur compounds with hydrogen peroxide is provided. The process employs solid supported polyacids comprising tungsten, molybdenum and/or vanadium as catalysts. The supports are selected from compounds, preferably oxides, of Group IIa, IIb, IIIb, IVa and IVb elements, and strong base ion exchange resins. Certain embodiments of the process provide for the oxidation of sulphides to sulphoxides or sulphones, particularly for the oxidation of penicillins to penicillin sulphoxides. Other embodiments of the process provide for the selective oxidation of thiols to sulphonic acids.

Oxidation of organosulphur compounds

A process for the oxidation of alkylaromatic compounds is provided. The process comprises oxidising a substrate alkylaromatic compound with a peroxygen compound in the presence of a source of cerium (III) or (IV), a source of bromide and a carboxylic acid or anhydride solvent. Preferably, the source of cerium is cerium (III) acetate, the source of bromide is sodium bromide and the solvent is acetic or propionic acid. The process is particularly suited to the selective oxidation of methylaromatic compounds to the corresponding aldehydes.

Oxidation of alkylaromatic compounds

A process for the catalysed oxidation of ketones to esters or lactones with hydrogen peroxide in the presence of a carboxylic acid or anhydride is provided. The process employs gamma alumina as a heterogeneous catalyst. In certain preferred embodiments the catalyst also contains a tungsten-containing heteropolyacid. Preferably, the heteropolyacid contains phosphorus. In a related process, the catalyst accelerates the formation of percarboxylic acid solutions.

Scott William Brown

Papers

Epoxidation using hydrogen peroxide and tungsten catalysts

The selective oxidation of toluenes to benzaldehydes by cerium(III), hydrogen peroxide and bromide ion

Oxidation of organosulphur compounds

Oxidation of alkylaromatic compounds

Oxidation of ketones