Leaching of amorphous V- and Ti-containing porous silica catalysts in liquid phase oxidation reactions

Deng, Yi; Lettmann, Christian; Maier, Wilhelm F.

doi:10.1016/s0926-860x(01)00471-9

Cited by 32 publications

(16 citation statements)

References 25 publications

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“…In order to understand whether the observed catalytic activity arises from true heterogeneous catalyst systems, we performed a series of leaching experiments, since leaching of active vanadia species during liquid phase reactions is reported for various vanadium-containing mesoporous materials [41,42]. Generally, leaching of the active metal species during the reaction was verified by the removal of the catalyst from the hot reaction mixture and the resubmission of the filtrate to the reaction conditions [40].…”

Section: Heterogeneity Studiesmentioning

confidence: 99%

Vanadium-containing ordered mesoporous silicas: Synthesis, characterization and catalytic activity in the hydroxylation of biphenyl

George

Shylesh

Singh

2005

Applied Catalysis A: General

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Section: Heterogeneity Studiesmentioning

confidence: 99%

Vanadium-containing ordered mesoporous silicas: Synthesis, characterization and catalytic activity in the hydroxylation of biphenyl

George

Shylesh

Singh

2005

Applied Catalysis A: General

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“…[4] As a result, much research has been carried out in order to prepare vanadium silicates with improved catalytic behaviour.…”

Section: Introductionmentioning

confidence: 99%

Hydrothermal Synthesis and Characterisation of Two Novel Large‐Pore Framework Vanadium Silicates

et al. 2003

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Two new large-pore sodium vanadium silicates, denoted AM-15 and AM-17 (Aveiro-Manchester, structures number 15 and 17) with framework composition Na 6 Si 14 V 4 O 39 and Na 4 CaSi 10 V 2 O 27 , respectively, are reported. Electron paramagnetic resonance (EPR), Fourier transform infrared (FTIR) and diffuse reflectance ultraviolet-visible (DR UV/Vis) spectroscopy reveal that as-prepared AM-15 contains both V IV and V V in a square pyramidal and tetrahedral coordination,

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“…However, since a sintered glass filter was used it is possible that small catalyst particles were not completely separated by this porous media and that MCM-41-3 is a truly heterogeneous catalyst. [17] The modified materials MCM-41-2 and MCM-41-3 were tested for the epoxidation of other olefins, namely cyclododecene, trans-2-octene and 1-octene. Olefin conversion after 24 hours decreases in the following order for both materials: cyclooctene Ͼ cyclododecene Ͼ trans-2-octene Ͼ 1-octene ( Figure 6).…”

mentioning

confidence: 99%

Incorporation of a (Cyclopentadienyl)molybdenum Oxo Complex in MCM‐41 and Its Use as a Catalyst for Olefin Epoxidation

et al. 2004

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The tricarbonyl complex [(η5‐C5H4‐COOMe)Mo(CO)3Cl] was prepared from the reaction of sodium (methoxycarbonyl)cyclopentadienide, (C5H4‐CO2Me)Na, with (Bu4N)[Mo(CO)5I]. Heating the ester with 3‐(triethoxysilyl)propylamine gave the amide derivative {[η5‐C5H4‐CONH‐C3H6Si(OEt)3]Mo(CO)3Cl}. The functionalised tricarbonyl complex was immobilised in the ordered mesoporous silica MCM‐41 with a loading of 13 wt.‐% Mo (1.4 mmol·g−1) by carrying out a grafting reaction in dichloromethane. Powder X‐ray diffraction and nitrogen adsorption−desorption analysis indicated that the structural integrity of the support was preserved during the grafting and that the channels remained accessible, despite significant reductions in surface area, pore volume and pore size. The success of the coupling reaction was confirmed by 29Si and 13C (CP) MAS NMR spectroscopy. A supported dioxo complex of the type [(η5‐C5H4R)MoO2Cl] was subsequently prepared by oxidative decarbonylation of the tethered tricarbonyl complex using tert‐butyl hydroperoxide (TBHP). The oxidised material is an active catalyst for the liquid phase epoxidation of cyclooctene with TBHP as the oxygen source. Similar catalytic results were obtained using the tethered tricarbonyl complex directly as a pre‐catalyst since fast oxidative decarbonylation occurs under the reaction conditions used. For both systems, the desired epoxide was the only product and the initial activities were about 13 mol·molMo−1·h−1. The solid catalysts were recycled several times. Some activity was lost between the first and second runs but thereafter tended to stabilise. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

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Leaching of amorphous V- and Ti-containing porous silica catalysts in liquid phase oxidation reactions

Cited by 32 publications

References 25 publications

Vanadium-containing ordered mesoporous silicas: Synthesis, characterization and catalytic activity in the hydroxylation of biphenyl

Vanadium-containing ordered mesoporous silicas: Synthesis, characterization and catalytic activity in the hydroxylation of biphenyl

Hydrothermal Synthesis and Characterisation of Two Novel Large‐Pore Framework Vanadium Silicates

Incorporation of a (Cyclopentadienyl)molybdenum Oxo Complex in MCM‐41 and Its Use as a Catalyst for Olefin Epoxidation

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