Lewis acidic Sn(IV) centers-grafted onto MCM-41-as catalytic sites for the Baeyer-Villiger oxidation with hydrogen peroxide

摘要

Sn(IV) centers have grafted onto mesoporous MCM-41 using different R_nSnX_(4-N) precursore For a successful incorporatin of the tin one or two alkyl substituents ar beneficial The calcined samples are able to ativate a carbonyl bond for uncleophilic attack as it could be shown by in situ IR Spectroscopy The resulting catalysts are active for the Baeyer-Villiger oxidation of various substrates with hydrogen peroxide and achieve good conversions and selectivities Chemoselective oxidations toward unsaturated lactones are obtained from unsaturated ketones The Lewis acidity adn the catalytic performance of the grafted Sn(IV) centers are very similar to the directly synthesized Sn-MCM-41 but lower than those of te Sn-Beta zeolite.