Epoxidation of Cyclohexene on Heterogenized Molybdenum Compounds

• Autor(a) principal: Barradas,E.F.M.
• Data de Publicação: 1998
• Outros Autores: Cestari,A.R., Airoldi,C., Buffon,R.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Journal of Chemical Engineering
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0104-66321998000200008
• topic: Epoxidation; molybdenum; functionalized silica

Heterogenization of molybdenum species, starting either with Mo(CO)6 or MoO2(acac)2, on the surface of functionalized silicas bearing one (Si-Et1) or two (Si-Et2) ethylenediamine ligands was studied. The resulting systems are active in the catalytic epoxidation of cyclohexene by tert-butyl hydroperoxide. Using fresh catalysts, Si-Et2 results in higher selectivity, regardless of the Mo precursor. However, MoO2(acac)2-based systems are far more active. Formation of diols was never detected. Although XPS analyses point mainly to Mo(VI) species on the surface of all systems, UV-vis spectra suggest different ligands in their coordination sphere