A DFT Study of Direct Oxidation of Benzene to Phenol by N<sub>2</sub>O over [Fe(μ-O)Fe]<sup>2+</sup> Complexes in ZSM-5 Zeolite

Fellah, Mehmet Ferdi; Pidko, Evgeny A.; Santen, Rutger A. van; Önal, Işık

doi:10.1021/jp201582s

Cited by 25 publications

(21 citation statements)

References 89 publications

(191 reference statements)

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“…These approximate transition state (ATS) geometries were obtained along a reaction coordinate. According to our very recent theoretical experience [32][33][34][35][36][37], transition states geometries were very close to the peak points of the profiles. Moreover, the activation barriers based on ATS calculated for ethylene epoxidation by using the Ag 14 O 9 (001) cluster [17] were in good agreement with the values computed on periodic silver oxide (001) slab surface [18].…”

Section: Discussionsupporting

confidence: 72%

“…The activation barrier data obtained for ethylene epoxidation by using the Ag 14 O 9 (001) cluster [17] were in good agreement with those obtained on periodic silver oxide (001) slab surface [18]. Although it has been reported [28] that hydrogen termination does not prevent the strain effect on a cluster such as Pt 35 cluster the dangling bonds of the silver and oxygen atoms were terminated with H atoms to obtain a neutral cluster. Terminating H atoms were not shown in the geometric representations.…”

Section: Surface Model and Calculation Methodssupporting

confidence: 66%

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Epoxidation of Propylene on a [Ag14O9] Cluster Representing Ag2O (001) Surface: A Density Functional Theory Study

Fellah

Önal

2011

Catal Lett

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Density functional theory calculations were employed to study partial oxidation of propylene on a [Ag 14 O 9 ] cluster representing Ag 2 O (001) surface for which positive effect for ethylene oxide formation has been reported in our earlier work at the same level of theory (Fellah et al., Catal Lett 141:762, 2011). Propylene oxide (PO), propanal, acetone and G-allyl radical formation reaction mechanisms were investigated. P-allyl formation path and two propylene adsorption paths resulting in PO formation are competing reactions on silver oxide (001) surface because of their comparable activation barriers (9, 8 and 9 kcal/mol, respectively) while P-allyl formation path is generally a more favorable path on Ag (111) surface as reported in previous theoretical literature. SO 2 adsorption calculations indicate that silver oxide has lower Lewis basicity relative to oxygen atom adsorbed on silver. Calculations also showed that surface oxygen atom of Ag 2 O (001) has a higher spin density compared to that of oxygen atom adsorbed on Ag (111), which indicates that oxygen atom on Ag 2 O (001) cluster has a more radical character.

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Section: Discussionsupporting

confidence: 72%

Section: Surface Model and Calculation Methodssupporting

confidence: 66%

Epoxidation of Propylene on a [Ag14O9] Cluster Representing Ag2O (001) Surface: A Density Functional Theory Study

Fellah

Önal

2011

Catal Lett

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“…This was consistent with mechanisms of stoichiometric methane or benzene oxidation over Fe-ZSM-5 resulting in (Fe III – OCH 3 ) α 19,23 or (Fe III –OPh) α groups. 24 Recently, Panov and co-workers 25 proposed a quasicatalytic reaction mechanism over Fe–H-ZSM-5 involving the surface diffusion of molecular methanol from the Fe III –O α active sites to the Brønsted acid sites. Desorption of methanol into the gas phase was not favorable under temperatures of 523 K; however, surface diffusion had a lower activation energy that allowed methanol to migrate within the zeolite at temperatures as low as 333 K. Unfortunately, no explanation was provided as to how molecular methanol was generated from surface methoxy species under water-free reaction conditions.…”

Section: Resultsmentioning

confidence: 99%

Methane to Acetic Acid over Cu-Exchanged Zeolites: Mechanistic Insights from a Site-Specific Carbonylation Reaction

et al. 2015

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The selective low temperature oxidation of methane is an attractive yet challenging pathway to convert abundant natural gas into value added chemicals. Copper-exchanged ZSM-5 and mordenite (MOR) zeolites have received attention due to their ability to oxidize methane into methanol using molecular oxygen. In this work, the conversion of methane into acetic acid is demonstrated using Cu-MOR by coupling oxidation with carbonylation reactions. The carbonylation reaction, known to occur predominantly in the 8-membered ring (8MR) pockets of MOR, is used as a site-specific probe to gain insight into important mechanistic differences existing between Cu-MOR and Cu-ZSM-5 during methane oxidation. For the tandem reaction sequence, Cu-MOR generated drastically higher amounts of acetic acid when compared to Cu-ZSM-5 (22 vs 4 μmol/g). Preferential titration with sodium showed a direct correlation between the number of acid sites in the 8MR pockets in MOR and acetic acid yield, indicating that methoxy species present in the MOR side pockets undergo carbonylation. Coupled spectroscopic and reactivity measurements were used to identify the genesis of the oxidation sites and to validate the migration of methoxy species from the oxidation site to the carbonylation site. Our results indicate that the CuII–O–CuII sites previously associated with methane oxidation in both Cu-MOR and Cu-ZSM-5 are oxidation active but carbonylation inactive. In turn, combined UV–vis and EPR spectroscopic studies showed that a novel Cu2+ site is formed at Cu/Al <0.2 in MOR. These sites oxidize methane and promote the migration of the product to a Brønsted acid site in the 8MR to undergo carbonylation.

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“…The possible formation and activity of α-oxygen, defined as the active oxygen that is formed when N 2 O reacts with ZSM-5 (212), in Fe-MFI was proposed by Yang et al (213) On the basis of DFT calculations, Fellah et al suggested that phenol formation on binuclear (Fe (μ-O) Fe) 2+ sites in ZSM-5 is facilitated (214) in the presence of water. These computational findings are consistent with experimental observations and allow a rationalization of the findings at a molecular level.…”

Section: Oxidation Of Benzene With N 2 Omentioning

confidence: 99%

Science and Technology of Framework Metal-Containing Zeotype Catalysts

Németh

Bare

2014

Advances in Catalysis

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A DFT Study of Direct Oxidation of Benzene to Phenol by N₂O over [Fe(μ-O)Fe]²⁺ Complexes in ZSM-5 Zeolite

Cited by 25 publications

References 89 publications

Epoxidation of Propylene on a [Ag14O9] Cluster Representing Ag2O (001) Surface: A Density Functional Theory Study

Epoxidation of Propylene on a [Ag14O9] Cluster Representing Ag2O (001) Surface: A Density Functional Theory Study

Methane to Acetic Acid over Cu-Exchanged Zeolites: Mechanistic Insights from a Site-Specific Carbonylation Reaction

Science and Technology of Framework Metal-Containing Zeotype Catalysts

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A DFT Study of Direct Oxidation of Benzene to Phenol by N2O over [Fe(μ-O)Fe]2+ Complexes in ZSM-5 Zeolite

Cited by 25 publications

References 89 publications

Epoxidation of Propylene on a [Ag14O9] Cluster Representing Ag2O (001) Surface: A Density Functional Theory Study

Epoxidation of Propylene on a [Ag14O9] Cluster Representing Ag2O (001) Surface: A Density Functional Theory Study

Methane to Acetic Acid over Cu-Exchanged Zeolites: Mechanistic Insights from a Site-Specific Carbonylation Reaction

Science and Technology of Framework Metal-Containing Zeotype Catalysts

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Product

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A DFT Study of Direct Oxidation of Benzene to Phenol by N₂O over [Fe(μ-O)Fe]²⁺ Complexes in ZSM-5 Zeolite