Some features of epoxidation of cyclohexene catalyzed by oxoperoxometallates under phase-transfer conditions
- A. Jozef Univ. (Hungary)
The epoxidation of cyclohexene with hydrogen peroxide was investigated in the biphasic water-chlorobenzene system. It was observed that the autoxidation of cyclohexene to 2-cyclohexenyl-hydroperoxide is inhibited by the presence of the aqueous phase, but the inhibition caused by water is largely eliminated by the application of a phase-transfer catalyst (PTC). It was found that the yield of epoxide increased nearly linearly with increasing concentration of molybdenum (VI) catalyst. A pH of 3-4 was found to be optimal for epoxide formation; the epoxide yield decreased with increase of the H{sup +} ion concentration mainly due to the H{sup +} ion-catalyzed hydrolysis of the epoxide formed. A PTC excess inhibits the epoxidation. In the case of molybdenum (VI). However, for tungsten (VO) the activity sequence was PO{sub 4}{sup 3{minus}} > AsO{sub 4}{sup 3{minus}}. The view is advanced that the enormous differences between the reactivities of the investigated oxoperoxometallate complexes and their heteropoly derivatives are connected with differences in the dissymmetry of the {eta}{sup 2} diperoxo-ligands in these complexes, which otherwise have similar structures.
- OSTI ID:
- 5598656
- Journal Information:
- Journal of Catalysis; (USA), Journal Name: Journal of Catalysis; (USA) Vol. 127:1; ISSN 0021-9517; ISSN JCTLA
- Country of Publication:
- United States
- Language:
- English
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020400* -- Petroleum-- Processing
ALKENES
ARSENATES
ARSENIC COMPOUNDS
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL REACTIONS
CYCLOALKENES
EPOXIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
HYDROGEN PEROXIDE
INHIBITION
MOLYBDENUM COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PEROXIDES
PH VALUE
PHOSPHATES
PHOSPHORUS COMPOUNDS
PROMOTERS
REFRACTORY METAL COMPOUNDS
SYNTHESIS
TRANSITION ELEMENT COMPOUNDS
TUNGSTEN COMPOUNDS
WATER