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

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

doi:10.1007/s10562-011-0614-2

Cited by 24 publications

(15 citation statements)

References 38 publications

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“…Different supported silver adsorbents have been reported in the selective removal of sulfur compounds from fuels via a strong complexation mechanism, including Ag 2 O/titania materials in jet fuel desulfurization [157,158], Ag + /SBA-15 and Ag + /SiO 2 for the selective adsorption of dibenzothiophene (DBT) [159], and Ag + supported zeolite and activated carbon for the adsorption of both BT and DBT [160,161]. Moreover, supported silver oxides or silver can also act as oxidative catalysts in the epoxidation of alkenes [162][163][164], aldehydes [165], and various organic compounds [166] and carbon oxide [167]. The capability of silver oxides to contemporarily perform as active catalytic species and adsorption phases has been applied in the ODS procedure by preparation of novel Ag x O-SBA-15 materials and their use in the adsorption/oxidation of BT, DBT, 4-MDBT and 4,6-DMDBT, as model fuel compounds [168].…”

Section: Silver Oxidesmentioning

confidence: 99%

SBA-15 Anchored Metal Containing Catalysts in the Oxidative Desulfurization Process

2019

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Recalcitrant sulfur compounds are common impurities in crude oil. During combustion they produce SOx derivatives that are able to affect the atmospheric ozone layer, increasing the formation of acid rains, and reducing the life of the engine due to corrosion. In the last twenty years, many efforts have been devoted to develop conventional hydrodesulfurization (HDS) procedures, as well as alternative methods, such as selective adsorption, bio-desulfurization, oxidative desulfurization (ODS) under extractive conditions (ECODS), and others. Among them, the oxidative procedures have been usually accomplished by the use of toxic stoichiometric oxidants, namely potassium permanganate, sodium bromate and carboxylic and sulfonic peracids. As an alternative, increasing interest is devoted to selective and economical procedures based upon catalytic methods. Heterogeneous catalysis is of relevance in industrial ODS processes, since it reduces the leaching of active species and favors the recovery and reuse of the catalyst for successive transformations. The heterogenization of different types of high-valent metal transition-based organometallic complexes, able to promote the activation of stoichiometric benign oxidants like peroxides, can be achieved using various solid supports. Many successful cases have been frequently associated with the use of mesoporous silicas that have the advantage of easy surface modification by reaction with organosilanes, facilitating the immobilization of homogeneous catalysts. In this manuscript the application of SBA-15 as efficient support for different active metal species, able to promote the catalytic ODS of either model or real fuels is reviewed, highlighting its beneficial properties such as high surface area, narrow pore size distribution and tunable pore diameter dimensions. Related to this topic, the most relevant advances recently published, will be discussed and critically described.

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Section: Silver Oxidesmentioning

confidence: 99%

SBA-15 Anchored Metal Containing Catalysts in the Oxidative Desulfurization Process

2019

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“…[9,10] In consequence, the integrated utilization of N 2 O with the direct hydroxylation of benzene is environmentally benign and thus becomes the first choice for Fe/ZSM-5 zeolite-based catalysts. [11,12] Graphene, an allotrope of carbon with 2D layer structures, is endowed with high surface area, mechanical strength, thermodynamic stability, and electronic conductivity. [13][14][15] Owing to these outstanding physiochemical properties, graphene exhibits high reactivity for a wide spectrum of catalytic reactions.…”

Section: Introductionmentioning

confidence: 99%

“…The greenhouse nitrous oxide (N 2 O) was used as oxidant, as recommended for other catalytic systems including Fe/ZSM-5 zeolite. [7][8][9][10][11][12] The pristine graphene (p-GN) in the ground state was firstly tested finding no catalytic effects. As reported, the adsorption and catalytic performances of graphene are regulated effectively by doping [28][29][30] or excitation, [31][32][33][34] while neither of these strategies seems valid for the present catalytic processes.…”

Section: Introductionmentioning

confidence: 99%

“…Currently, the three‐step cumene process is the industrial approach to manufacture phenol, which has several disadvantages such as high‐energy consumption and difficulty for product separation . From the standpoint of targeted phenol production, the direct hydroxylation of benzene is definitely more attractive and oxygen (O 2 ), hydrogen peroxide (H 2 O 2 ), and nitrous oxide (N 2 O) have been tested as oxidants. Especially, nitrous oxide (N 2 O) has a comparable destruction to stratospheric ozone as chlorofluorocarbons (CFCs) and its global warming potential is 300 times greater than that of carbon dioxide (CO 2 ).…”

Section: Introductionmentioning

confidence: 99%

“…In this work, an alternative route for the direct hydroxylation of benzene to phenol over graphene‐based catalysts was computationally designed. The greenhouse nitrous oxide (N 2 O) was used as oxidant, as recommended for other catalytic systems including Fe/ZSM‐5 zeolite . The pristine graphene (p‐GN) in the ground state was firstly tested finding no catalytic effects.…”

Section: Introductionmentioning

confidence: 99%

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Facile and Direct Hydroxylation of Benzene to Phenol over Graphene‐Based Catalysts: Integrated Utilization of Greenhouse Nitrous Oxide

Zhu

Yun

Wang

et al. 2018

Advcd Theory and Sims

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Graphene catalysis has recently emerged as a focus and herein a novel and highly efficient process is computationally designed using graphene-based catalysts that integrates the utilization of greenhouse nitrous oxide (N 2 O) as oxidant. The ground-state pristine graphene is not catalytically active for benzene hydroxylation, and doping and photocatalysis through excitations are employed to improve the catalyst systems, while both strategies exhibit limited effects. A combination of Be-doping and photocatalysis through excitations results in encouraging changes, where all energy barriers are moderate, so that the whole catalytic processes proceed facilely at mild conditions. Graphene materials, especially Be-and O-doped ones, are good photocatalysts due to the low excitation energies. Mechanistic studies indicate that the active sites of the excited-state graphene, whether pristine or doped, are oxygen anion radical (O −• ) and distinct from the epoxide species for the ground state; in addition, Be-doping pronouncedly reduces the excitation energies and enhances the interactions with the active-site O species, which further show strong stabilization effects to transition states and reduce substantially the energy barriers.

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Chlorine and Caesium Promotion of Silver Ethylene Epoxidation Catalysts

2013

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The effect of co‐adsorbed Cs and Cl on the selectivity of ethylene epoxidation was studied computationally on an Ag2O(0 0 1) surface model. Cl blocks the oxygen vacant sites and prevents oxometallacycle (OMC) formation, which is responsible for aldehyde formation on the oxide surface. Cl also prevents unfavorable surface reconstruction induced by co‐adsorption of ethylene. It also has a positive effect on the stability of selective oxygen species when Cs co‐exists. Introduction of Cs on the Ag2O(0 0 1) surface results in the formation of CsOx‐type of complexes in the absence of Cl. Whereas oxygen atom adsorption energies are increased, Cs also introduces surface oxygen vacancies that reduce catalyst selectivity. Cs and Cl co‐exist on the surface in the form of CsClxOy complexes. Under reaction conditions, these complexes stabilize the oxide surface and reduce oxygen surface vacancy formation, which results in higher ethylene oxide (EO) selectivity.

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

Cited by 24 publications

References 38 publications

SBA-15 Anchored Metal Containing Catalysts in the Oxidative Desulfurization Process

SBA-15 Anchored Metal Containing Catalysts in the Oxidative Desulfurization Process

Facile and Direct Hydroxylation of Benzene to Phenol over Graphene‐Based Catalysts: Integrated Utilization of Greenhouse Nitrous Oxide

Chlorine and Caesium Promotion of Silver Ethylene Epoxidation Catalysts

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