Glycol-modified molybdate catalysts for efficient singlet oxygen generation from hydrogen peroxide
作者:Joos Wahlen、Dirk De Vos、Walther Jary、Paul Alsters、Pierre Jacobs
DOI:10.1039/b704238h
日期:——
Pretreatment of molybdate-exchanged layered double hydroxides in polyalcohols such as ethylene glycol affords heterogeneous catalysts showing largely improved oxidant efficiency compared to the unmodified materials.
Lanthanum-exchanged zeolites as active and selective catalysts for the generation of singlet oxygen from hydrogen peroxide
作者:Joos Wahlen、Dirk De Vos、Sigrid De Hertogh、V�ronique Nardello、Jean-Marie Aubry、Paul Alsters、Pierre Jacobs
DOI:10.1039/b414597f
日期:——
Lanthanum(III)-exchanged zeolites Beta and USY are active and selective catalysts for the generation of singletoxygenfrom H2O2 showing superior activity and oxidant efficiency compared to unsupported La-catalysts, e.g. La(OH)3.
Porphyrin-Functionalized Dendrimers: Synthesis and Application as Recyclable Photocatalysts in a Nanofiltration Membrane Reactor
作者:Suhas A. Chavan、Wouter Maes、Lieven E. M. Gevers、Joos Wahlen、Ivo F. J. Vankelecom、Pierre A. Jacobs、Wim Dehaen、Dirk E. De Vos
DOI:10.1002/chem.200500251
日期:2005.11.4
porphyrin catalysts. Recycling of the dendrimer-enlarged homogeneous photocatalysts was possible by solvent-resistant nanofiltration (SRNF) by using an oxidatively stable membrane consisting of a polysiloxane polymer and ultrastable Y zeolite as inorganic filler. Moreover, this membrane technology provides a safe way to isolate the hydroperoxide products under very mild conditions. The membrane showed high
Kinetics of the Oxygenation of Unsaturated Organics with Singlet Oxygen Generated from H<sub>2</sub>O<sub>2</sub> by a Heterogeneous Molybdenum Catalyst
作者:Bert F. Sels、Dirk E. De Vos、Pierre A. Jacobs
DOI:10.1021/ja065849f
日期:2007.5.1
A heterogeneous catalyst containing MoO42- exchanged on layered double hydroxides (Mo-LDHs) is used to produce O-1(2) from H2O2, and with this dark O-1(2), unsaturated hydrocarbons are oxidized in allylic peroxides. The oxidation kinetics are studied in detail and are compared with the kinetics of oxidation by O-1(2), formed from H2O2 by a homogeneous catalyst. A model is proposed for the heterogeneously catalyzed O-1(2) generation and peroxide formation. The model divides the reaction suspension in two compartments: (1) the intralamellar and intragranular zones of the LDH catalyst; (2) the bulk solution. The 2-compartment model correctly predicts the oxidant efficiency and peroxide yield for a series of olefin peroxidation reactions. O-1(2) is generated at a high rate by the heterogeneous catalyst, but somewhat more O-1(2) is lost by quenching with the heterogeneous catalyst than using the homogeneous catalyst. Quenching occurs mainly as a result of collision with the LDH hydroxyl surface, as is evidenced by using LDH supports containing strong O-1(2) deactivators such as Ni2+. A total of 15 organic substrates were peroxidized on a preparative scale using the best Mo-LDH catalyst under optimal conditions.