Kinetic and adsorption studies on vapor-phase catalytic oxidation of olefins over silver

Akimoto, Masamichi; Ichikawa, Kazuyoshi; Echigoya, Etsuro

doi:10.1016/0021-9517(82)90264-0

Cited by 85 publications

(16 citation statements)

References 17 publications

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“…The activation barriers of the rate-limiting steps for the formation of EO mechanisms (via ethyleneoxy and non-activated paths) were found as 20 and 14 kcal/mol, respectively. These values are in good agreement with the experimental activation energy values (14 [5], 17 [6,8] and 22 [7]) for EO formation on silver catalyst. Additionally the results obtained on silver oxide (001) surface cluster are relatively similar with the results produced on periodic slab silver oxide (001) surface.…”

Section: Discussionsupporting

confidence: 89%

“…The activation barrier of the step 2b on the silver oxide (001) surface was calculated to be 20 kcal/mol, which is close to the theoretical value of 17 kcal/mol although it was obtained on surface oxide structure layer on Ag(111) [15]. This value also well match with the experimental values (14 [5], 17 [6,8] and 22 [7] kcal/mol) found for ethylene oxidation to ethylene oxide on Ag/a-Al 2 O 3 catalyst. Furthermore, in the study of Ozbek et al [14] the barrier value for the reaction of opening of the adsorbed EO to form surface intermediate (ethyleneoxy) was reported as 21 kcal/mol.…”

Section: Discussionsupporting

confidence: 55%

“…1b) in related reference [14] h EO was formed by step 2b i EO was formed by step 1c (non-activated path) j EO was directly produced via non-activated path on periodic silver oxide (001) slab surface k Akimoto et al [5] l Kanoh et al [10]. Moreover, Ozbek et al [14] has also recently reported that oxometallocycle intermediate was not formed on periodic slab silver oxide Ag 2 O (001) surface.…”

Section: Discussionmentioning

confidence: 97%

“…Grant and Lambert [4] carried out fundamental studies using primarily Ag(111) and Ag(110) crystals which provided evidence for the key role of atomic rather than molecular oxygen in both the epoxidation and combustion reactions. Ethylene epoxidation on silver catalyst has been experimentally studied by several research groups [5][6][7][8]. As part of a continuing effort to understand the mechanism of olefin epoxidation, Barteau and co-workers [9,10] used density functional theory (DFT) calculations to investigate surface oxometallocycles on silver.…”

Section: Introductionmentioning

confidence: 99%

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Epoxidation of Ethylene by Silver Oxide (Ag2O) Cluster: A Density Functional Theory Study

2011

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Density functional theory (DFT) calculations were employed to study epoxidation of ethylene on a [Ag 14 O 9 ] cluster model representing silver oxide (001) surface. Theoretical results obtained in this study showed that formation paths of acetaldehyde and vinyl alcohol have higher activation barriers than that of ethylene oxide formation path on silver oxide (35 and 35 vs. 20 kcal/mol). Formation of the ethylene oxometallocycle intermediate is found to have a low probability on Ag 2 O(001) surface. The essential reason for this may be lower basicity of surface oxygen atom on silver oxide surface and the absence of a surface vacancy position to activate ethylene. Adsorbed EO is formed on Ag 2 O surface cluster without an activation barrier. The activation barriers of the rate-limiting steps for the production of EO mechanisms (via ethyleneoxy and non-activated paths, 20 vs. 14 kcal/mol) are in relatively good agreement with the experimental activation energy values (14, 17 and 22 kcal/mol) reported for EO formation on silver catalyst.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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Epoxidation of Ethylene by Silver Oxide (Ag2O) Cluster: A Density Functional Theory Study

2011

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“…Following the success of ethylene epoxidation by silver-based catalysts [1][2][3], direct gas-phase propylene epoxidation using molecular oxygen has also been extensively studied. The propylene oxide (PO) selectivities were found to be very poor for silver due to the higher reactivity of propylene compared to ethylene.…”

Section: Open Accessmentioning

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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Theoretical studies on the catalytic activity of Ag surface for the oxidation of olefins

Nakatsuji

Nakai

1997

Int. J. Quant. Chem.

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ABSTRACT:Systematic theoretical studies for the mechanisms of the epoxidation and complete oxidation of ethylene and propylene over silver surface as well as the reactivity and the stability of oxygen species on Cu, Ag, and Au surfaces have been presented. The Ž . Ž . dipped adcluster model DAM combined with the ab initio Hartree᎐Fock HF , second-Ž . Ž order Møller-Plesset MP2 , and SACrSAC-CI symmetry-adapted clusterrconfiguration . interaction methods are used. These studies clarify the origin of silver as a unique effective catalyst for the epoxidation of ethylene and the different mechanisms for the oxidation of olefins over silver surface. For the epoxidation of ethylene, the superoxide O y , which is molecularly adsorbed in bent end-on geometry on the silver surface, is the 2 active species. The origin of the unique catalytic activity of silver for the epoxidation of ethylene is due to its ability to adsorb oxygen as the superoxide species. Such an adsorbed species cannot be stable or exist on Cu and Au surfaces. For the oxidation of propylene, both reaction mechanisms initiated by the activation of olefinic carbon and by the activation of the allyl hydrogen exist. The activation of the allyl hydrogen is the origin of the complete oxidation of some olefins over silver surface. The present results not only let us have a better understanding of the reaction mechanisms of olefins over silver surface but also supply a basic idea for the new catalyst design of the epoxidation reaction.

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Kinetic and adsorption studies on vapor-phase catalytic oxidation of olefins over silver

Cited by 85 publications

References 17 publications

Epoxidation of Ethylene by Silver Oxide (Ag2O) Cluster: A Density Functional Theory Study

Epoxidation of Ethylene by Silver Oxide (Ag2O) Cluster: A Density Functional Theory Study

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

Theoretical studies on the catalytic activity of Ag surface for the oxidation of olefins

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