Gas-phase catalytic oxidation of benzene over Cu-supported ZSM-5 catalysts: an attempt of one-step production of phenol

Yamanaka, Hiromitsu; Hamada, Rei; Nibuta, Hiroshi; Nishiyama, Satoru; Tsuruya, Shigeru

doi:10.1016/s1381-1169(01)00279-5

Cited by 79 publications

(53 citation statements)

References 23 publications

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“…Interestingly, other oxygenated products like benzoquinone and benzofuran were observed also in the absence of BrØnsted acid sites. Earlier gas phase work did not pay specific attention to the BrØnsted acid sites [2][3][4][5]. Ø On zeolites with a high affinity for the total oxidation, the formation of deep oxidation products (CO, CO 2 ) can be decreased by reducing the O 2 flow.…”

Section: Discussionmentioning

confidence: 99%

“…Nitrogen and oxygen were used as received. Before starting the reaction, all catalysts were activated using the following temperature program [2]. About 25 mg of the zeolite were heated up to 773 K in flowing air (N 2 flow: 32 ml/min, O 2 flow: 8 ml/min) with a heating rate of 1 K/min.…”

Section: Gas Phase Oxidation Of Benzene With Molecular Oxygenmentioning

confidence: 99%

“…Hamada et al explored the gas-phase reaction on several Cu/HZM5-zeolites under different reaction conditions and reported a phenol yield up to 5% with a selectivity of nearly 30% [2][3][4]. Meanwhile phenol yields up to 10% have been reported [5], but the detailed reaction mechanism for the phenol formation is still unknown.…”

Section: Introductionmentioning

confidence: 99%

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Aerobic one-step oxidation of benzene to phenol on copper exchanged HZSM5 zeolites: A mechanistic study

Tabler

Häusser

Roduner

2013

Journal of Molecular Catalysis A: Chemical

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Various Cu/HZSM5-zeolites were prepared and their catalytic properties were investigated by product analysis via GC/MS chromatography in order to trace down the mechanism of the gas phase one-step oxidation of benzene to phenol with molecular oxygen. Comparison of Cu free and Cu containing zeolites showed that the activation of O 2 takes place at copper centers of the zeolite and high copper loadings lead to high yields of deep oxidation products (CO, CO 2 ). No phenol was formed in the absence of BrØnsted acid sites, i.e. on Cu/KZSM5, revealing the bifunctionality of the Cu/HZSM5 zeolite. The yields of the various oxidation products and thus the selectivity towards phenol can be influenced by variation of the relative O 2 concentration in the reaction mixture, indicating the possibility of a stoichiometric use of O 2 . The role of the superoxide radical ion O 2•-as a reactive intermediate is discussed and a radical ionic reaction mechanism is suggested.

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Section: Discussionmentioning

confidence: 99%

Section: Gas Phase Oxidation Of Benzene With Molecular Oxygenmentioning

confidence: 99%

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Aerobic one-step oxidation of benzene to phenol on copper exchanged HZSM5 zeolites: A mechanistic study

Tabler

Häusser

Roduner

2013

Journal of Molecular Catalysis A: Chemical

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“…148,149 A Cu/ ZSHM-5 catalyst showed a maximum phenol selectivity of 60% with a phenol yield of 1.2% at 673 K. 150 However, the selective oxidation of benzene using O 2 was nominated as one of the ten most difficult challenges in catalysis 177179 and indeed there have been no reports on direct remarkable catalysts for phenol synthesis with performance greater than 5% benzene conversion and 50% phenol selectivity over the last 50 years.…”

Section: Tadamentioning

confidence: 99%

Surface-Mediated Design and Catalytic Properties of Active Metal Complexes for Advanced Catalysis Creation

Tada¹

2010

Bulletin of the Chemical Society of Japan

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Molecular-scale design of catalytically active structures at oxide surfaces is highlighted, focusing on our recent challenges for selective heterogeneous catalysis. We found novel structural transformations of supported metal complexes on oxide surfaces and achieved unique selective catalysis for various chemical syntheses. In this account, the advanced design of supported metal-complex catalysts on oxide surfaces and the in situ characterization of their structural kinetics, which means kinetics of structural changes of catalysts themselves, under catalyst-working conditions are reviewed. Surface-Mediated Design of Catalytically ActiveStructures for Selective Catalysis 1.1 Introduction: Metal-Complex Attaching on Oxide Surfaces. Heterogeneous solid catalysts have been widely utilized for the industrial production of many synthetic chemicals. The advantages of heterogeneous catalysts are not only the separation of catalysts and products from reaction media but also their high durability and catalytic activities resulting from the unique structures of catalytically active sites at solid surfaces. Relationships among the metal structures, organized environment, and the catalytic properties of surface species tell us the nature of catalysis and new strategy for rational design of heterogeneous catalysts.Metal-complex attachment to oxide surfaces is a practical way to produce molecularly regulated structures of active metal species on oxide surfaces, and subsequent structural transformation in a controllable manner often provides unique regulated metal structures active for selective catalytic reactions. 116 There are several types of metal-complex attachment techniques: coordination of metal-complex precursors to immobilized ligands on organic polymers, 1721 coordination of metal-complex precursors to functional ligands bound to oxide surfaces, 2,4,2225 intercalation into clay materials, 26 ion exchange into porous materials such as zeolite and mesoporous silica, 27 and direct attachment of metal-complex precursor onto oxide surfaces. 3,6,11,28,29 The interfacial attachment between a metal complex and an oxide surface can produce unique metal coordination different from the original metal-complex precursor. For example, SiOH is reacted with a M(CH 3 ) complex and a M(OSi) complex is produced, releasing CH 4 . A chemical bond between a metal-complex precursor and a support surface modifies the reactivity of the supported metal complex, resulting in novel catalytic activity the precursor complex does not exhibit. 3,6,11,28,29 Traditional ion-exchange on zeolites and intercalation to clay materials are also typical ways to introduce metal species onto solid supports although the valences and types of metal precursors are restricted. 4 Direct reactions of metal-complex precursors and hydroxy groups on oxide surfaces create novel metal-coordination structures, and many important factors for selective catalysis can be controlled at the interface, such as electronic properties and coordination sphere of the attached metal...

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“…10-11 ZSM-5 is a type of common zeolites, which has been exhibited excellent catalytic activities. [12][13][14][15][16][17] VOCs are usually emitted in mixture to nature; however, there are few articles about their treatment under this form. The different studies agree on the fact that VOC catalytic oxidation in mixture differs from its simple oxidation.…”

Section: Introductionmentioning

confidence: 99%

Gas Phase Oxidation of Toluene and Ethyl Acetate over Proton and Cobalt Exchanged ZSM-5 Nano Catalysts- Experimental Study and ANN Modeling

Hosseini¹,

Niaei²,

Salari³

et al. 2010

Bulletin of the Korean Chemical Society

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Activities of nanostructure HZSM-5 and Co-ZSM-5 catalysts (with different Co-loading) for catalytic conversion of ethyl acetate and toluene were studied. The catalysts were prepared by wet impregnation method and were characterized by XRD, BET, SEM, TEM and ICP-AES techniques. Catalytic studies were carried out inside a U-shaped fixed bed reactor under atmospheric pressure and different temperatures. Toluene showed lower reactivity than ethyl acetate for conversion on Co-ZSM-5 catalysts. The effect of Co loading on conversion was prominent at temperatures below 400 o C and 450 o C for ethyl acetate and toluene respectively. In a binary mixture of organic compounds, toluene and ethyl acetate showed an inhibition and promotional behaviors respectively, in which the conversion of toluene was decreased at temperatures above 350 o C. Inhibition effect of water vapor was negligible at temperatures above 400 o C. An artificial neural networks model was developed to predict the conversion efficiency of ethyl acetate on Co-ZSM-5 catalysts based on experimental data. Predicted results showed a good agreement with experimental results. ANN modeling predicted the order of studied variable effects on ethyl acetate conversion, which was as follows: reaction temperature (50%) > ethyl acetate inlet concentration (25.085%) > content of Co loading (24.915%).

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Gas-phase catalytic oxidation of benzene over Cu-supported ZSM-5 catalysts: an attempt of one-step production of phenol

Cited by 79 publications

References 23 publications

Aerobic one-step oxidation of benzene to phenol on copper exchanged HZSM5 zeolites: A mechanistic study

Aerobic one-step oxidation of benzene to phenol on copper exchanged HZSM5 zeolites: A mechanistic study

Surface-Mediated Design and Catalytic Properties of Active Metal Complexes for Advanced Catalysis Creation

Gas Phase Oxidation of Toluene and Ethyl Acetate over Proton and Cobalt Exchanged ZSM-5 Nano Catalysts- Experimental Study and ANN Modeling

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