Heterogeneous liquid-phase decomposition of cyclohexenyl-hydroperoxide in cyclohexene with manganese dioxide as catalyst

Liquid-phase oxidation of cyclohexanone over cerium oxide catalyst

“…The fractional order of 0.5 can be explained by assuming that the initiating reaction is of first order with respect to the weight of the catalyst (eq 24), while the termination of the chains occurs homogeneously by bimolecular recombination of peroxy radicals (reaction 19) and thus is independent of the presence of the catalyst. A fractional order with respect to catalyst surface area was found by other workers (Mukherjee and Graydon, 1967;Caloyannis and Graydon, 1971;Varma and Graydon, 1973;Neuberg et al, 1974Neuberg et al, ,1975 in the studies on the oxidation of xylene, cyclohexene, and tetralin.…”

“…The homogeneous liquid-phase oxidation of cyclohexanone proceeds through a free-radical mechanism like the liquid-phase oxidation of other hydrocarbons (Berezin et al, 1966;Kamiya, 1971;Sheldon and Kochi, 1976;Druline, 1978). A heterogeneous-homogeneous reaction mechanism has been proposed in the case of hydrocarbons using transition-metal oxides (Mukherjee and Graydon, 1967;Caloyannis and Graydon, 1971;Neuberg et al, 1972Neuberg et al, , 1974Sadana and Katzer, 1974a,b). The reaction involves initiation of free radicals on the catalyst surface and propagation of the reaction chain in homogeneous solution.…”

“…Studies of the liquid-phase oxidation of hydrocarbons have been carried out extensively by employing transition-metal oxides (Mukherjee and Graydon, 1967;Caloy-annis and Graydon, 1971; Neuberg et al, 1972Neuberg et al, ,1974Neuberg et al, ,1975Varma and Graydon, 1973;Sadana and Katzer, 1974a,b; Sri vasta va and Srivastava, 1975). The similarity of the reaction mechanism between the homogeneous and heterogeneous reactions has been reported (Caloyannis and Graydon, 1971; Sadana and Katzer, 1974a,b; Shen and Weng, 1988).…”

Liquid-phase oxidation of cyclohexanone to dibasic acids with immobilized cobalt catalyst

“…For example, transition-metal oxides are used for the oxidation of cyclohexene, phenol, p-xylene, acetic acid, cumene, etc. (Mukherjee and Graydon, 1967;Neuberg et al, 1972Neuberg et al, ,1974Neuberg et al, , 1975Varma and Graydon, 1973;Sadana and Katzer, 1974a,b;Srivastava and Srivastava, 1975; Levee and Smith, 1976; Hronec and Hrabe, 1986); cation-exchanged zeolites are used for the oxidation of butene and cyclopentene (Van Sickle and Prest, 1970); and cobalt-exchanged resins are used for the oxidation of acetaldehyde, benzoaldehyde, alkyl aromatics, etc. (Chou and Lee, 1985;Waller, 1986;Kuo, 1987).…”

Liquid-Phase Cooxidation of Cyclohexane and Cyclohexanone over Supported Cerium Oxide Catalysts

“…Herein, we did not observe an induction period if γ-Al 2 O 3 and V 2 O 5 were used as catalysts. According to some investigations, the induction period appeared only at higher catalyst loadings (Varma and Graydon, 1973;Neuberg et al, 1972;Neuberg et al, 1974). In a study on the aqueous-phase catalytic oxidation of phenol over copper oxide, Sadana and Katzer (1974) observed no induction period; however, the induction period would appear when some kind of support was added.…”