The effect of mesoporous scale defects on the activity of Au/TS-1 for the epoxidation of propylene

Taylor, Bradley; Lauterbach, Jochen A.; Delgass, W. Nicholas

doi:10.1016/j.cattod.2007.01.005

Cited by 58 publications

(32 citation statements)

References 34 publications

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“…The slight decrease of the E g values and the apparent impoverishment of the catalytic behavior higher selectivity values (around 90%) can be found in other related works in gas-phase conditions, such as Au/Ti-SiO 2 catalyst in H 2 /O 2 gas streams compositions, but in these catalysts lower propylene conversion are obtained [7,56,57]. On the other hand, the catalyst based on alkaline salts (K + or Na + ) doped iron silica require very powerful oxidizing agents, such as N 2 O (without the presence of H 2 in the gas stream), to achieve PO selectivities around 60% for propylene conversions below 10% [26,58].…”

Section: Propylene Epoxidation Reactionsupporting

confidence: 53%

One step-synthesis of highly dispersed iron species into silica for propylene epoxidation with dioxygen

García-Aguilar

Miguel-García

Juan-Juan

et al. 2016

Journal of Catalysis

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Well dispersed iron catalysts were synthesized in silica (Fe 0.0X SiO 2 ) by a one-step synthesis procedure. These materials were tested in the propylene epoxidation reaction with gaseous O 2 . The influence of the iron metal loading on the iron incorporation and distribution in the support (both influenced by the synthetic procedure) were thoroughly studied (conversion, generation and selectivity). Electron Microscopy and UltraViolet-Visible (UV-VIS), Raman and Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy techniques were used to analyze the iron distribution in the catalysts and to probe its incorporation into the silica framework. Insitu FTIR was also used to analyze the interaction between propylene and iron-based catalysts. This is a previous version of the article published in Journal of Catalysis. 2016Catalysis. , 338: 154-167. doi:10.1016Catalysis. /j.jcat.2016 2 Computational calculations considering a single-site iron catalyst incorporated into the silica structure show a possible interaction between O 2 and the incorporated iron atom and the olefin bond and the acidic proton neighboring the iron species which favours the reaction between the two molecules near the iron atom.

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Section: Propylene Epoxidation Reactionsupporting

confidence: 53%

One step-synthesis of highly dispersed iron species into silica for propylene epoxidation with dioxygen

García-Aguilar

Miguel-García

Juan-Juan

et al. 2016

Journal of Catalysis

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“…In fact, TS-1 nanocrystals with ~600 nm of size and containing very elevated titanium content (Si/Ti=35, ~2.0 % wt) were obtained ( Table 1). In these samples, the totality of the titanium was tetrahedrally coordinated into the zeolitic framework, being this fact important to remark because it was reported that when high amounts of titanium are incorporated, significant octahedral extra-framework titanium was obtained, which is not active for epoxidation processes [44,45]. UV-vis analysis and SEM inspection confirmed that the coordination state of the titanium on one hand, and the size distribution of the TS-1 crystals on the other, as shown in Figure 2.…”

Section: Synthesis and Characterization Of Catalystsmentioning

confidence: 99%

Propylene epoxidation with in situ generated H2O2 in supercritical conditions

et al. 2014

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ElsevierPrieto Arnal, A.; Palomino Roca, M.; Díaz Morales, UM.; Corma Canós, A. (2014). Propylene epoxidation with in situ generated H2O2 in supercritical conditions. Catalysis Today. 227:87-95. doi:10.1016Today. 227:87-95. doi:10. /j.cattod.2013 AbstractSeveral bi-functional materials based in palladium nanoparticles supported onto nanocrystalline titanium silicalite zeolite (Pd@TS-1) were prepared and used as active and reusable catalysts to direct PO production from hydrogen, oxygen and propylene through onepot two-step combined process. This type of catalysts was able to carry out the consecutive process where palladium nanoparticles catalyzed the formation of H 2 O 2 that was used as intermediate reagent for propylene epoxidation catalyzed by TS-1 nanocrystals, used as supporting active matrix. Influence of supercritical CO 2 conditions in batch reactions was evaluated together with the associated effect due to the presence of platinum promoters (Pd(Pt)@TS-1). Another reaction parameters were also considered, such as palladium loading, use of acidity inhibitors and modification of H 2 /O 2 /C 3 = ratio. Reusability studies showed the high stability of the catalysts in consecutive catalytic cycles, being possible their regeneration.

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“…Delgass and co-workers have also been deeply involved in studying propylene epoxidation over gold-based catalysts [16][17][18][19][20].…”

Section: Scheme 2 Epoxidation Of Propenementioning

confidence: 99%

“…A unique design of experiments combining the best features of factorial experiments with one-at-a-time experimentation over the nonflammable range was used to collect kinetic information, from which a power rate law was extracted. Explaining the resultant fractional reactant orders (O 2 = 0.31 ± 0.04, H 2 = 0.60 ± 0.03, and C 3 H 6 = 0.18 ± 0.04) required a sequence of elementary kinetic steps having a minimum of two active sites participating in the rate-determining step [18,19]. A reaction sequence was proposed that accounted for the experimentally determined reaction orders and was consistent with DFT calculations [20] (Figure 3).…”

Section: Scheme 2 Epoxidation Of Propenementioning

confidence: 99%

Monometallic Supported Gold Catalysts in Organic Transformations: Ring Making and Ring Breaking

2012

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Supported gold catalysts are highly active in oxidation reactions. Beside the most frequently studied CO oxidation, they are readily applied in the epoxidation of more or less complex olefinic compounds using air or oxygen directly or other oxidants like peroxides of various kinds. Less frequently though, the reverse reaction, ring opening with single or double C-O scission is also investigated. These and other ring making and breaking reactions are reviewed, and the catalytic roles of gold species are described.

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The effect of mesoporous scale defects on the activity of Au/TS-1 for the epoxidation of propylene

Cited by 58 publications

References 34 publications

One step-synthesis of highly dispersed iron species into silica for propylene epoxidation with dioxygen

One step-synthesis of highly dispersed iron species into silica for propylene epoxidation with dioxygen

Propylene epoxidation with in situ generated H2O2 in supercritical conditions

Monometallic Supported Gold Catalysts in Organic Transformations: Ring Making and Ring Breaking

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