Ozone silica support

C. Reed, Y. Xi, S. T. Oyama, Distinguishing between reaction intermediates and spectators A kinetic study of acetone oxidation using ozone on a silica-supported manganese oxide catalyst, J. Catal. 235 (2005) 378. 

Rakovski, S. K. , Nenchev, L. K. Cherneva, D. R. Shopov, D. M. Mechanism of the Reaction of Ozone with Cumene in the Presence of Silica-Supported Mo03 and V205 Catalysts. Comm. Dep. Chem-Bulgarlan Academy of Sciences 1979, 12(2),25A- 251. 

Several references have appeared on the use of solid-phase oxidants. Solid potassium permanganate-copper sulphate mixtures oxidize secondary alcohols to ketones in high yield, and pyridinium chromate or chromic acid on silica gel are described as convenient off-the-shelf reagents for oxidation of both primary and secondary alcohols. Anhydrous chromium trioxide-celite effects similar transformations only when ether is present as co-solvent. An excellent review, with over 400 references, on supported oxidants covers the use of silver carbonate-celite, chromium trioxide-pyridine-celite, ozone-silica, chromyl chloride-silica, chromium trioxide-graphite, manganese dioxide-carbon, and potassium permanganate-molecular sieve. 

Although the decomposition of ozone to dioxygen is a thermodynamically favoured process,126 it is thermally stable up to 523 K and catalysts are needed to decompose it at ambient temperature in ventilation systems, in the presence of water vapour and at high space velocity. A limited number of catalysts have been evaluated and active components are mainly metals such as platinum, palladium and rhodium, and metal oxides including those of manganese, cobalt, copper, iron, nickel and silver. Supports that have been used include 7-alumina, silica, zirconia, titania and activated carbon.125,170... 

Polymer encapsulated sorbents have been prepared by peroxide-induced or ozone-induced free radical crosslinking of coated porous silica or diatomaceous supports at elevated temperatures [175]. By reloading and performing sequential crosslinking reactions up to 20% (w/w) of liquid phase can be immobilized over the support surface. This reaction is analogous to the widely used procedure for immobilizing stationary phases in open tubular colunms. Few practical applications have been demonstrated. 

Potassium permanganate supported on silica causes the oxidative cleavage of carbon-carbon double bonds [120]. The reaction is largely unaffected by substituents on the double bond, even when electron withdrawing groups are present. Ozone adsorbed on silica gel oxidises hydrocarbons selectively to their corresponding alcohols [131]. 

FeH(CO)4] supported on Amberlyst A-26. ° Tetrabutylammonium permanganate has now been described, permitting permanganate oxidations in pyridine/ Remote positions may be oxidized regioselectively by ozone adsorbed on silica gel/ ... 

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