Open AccessEpoxidation of Cyclohexene on Heterogenized Molybdenum Compounds
Author(s) -
E.F.M. Barradas,
Antonio R. Cestari,
Cláudio Airoldi,
Regina Buffon
Publication year - 1998
Publication title -
brazilian journal of chemical engineering/brazilian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.313
H-Index - 52
eISSN - 1678-4383
pISSN - 0104-6632
DOI - 10.1590/s0104-66321998000200008
Subject(s) - cyclohexene , catalysis , molybdenum , ethylenediamine , chemistry , selectivity , coordination sphere , x ray photoelectron spectroscopy , inorganic chemistry , polymer chemistry , organic chemistry , molecule , chemical engineering , engineering
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 spher