Novel Mesoporous Nanocomposite WO<sub><i>x</i></sub>-Silicate Acidic Catalysts: Ethylene and Diethylether from Ethanol

Varışlı, Dilek; Doğu, Timur; Doğu, Gülşen

doi:10.1021/ie8008154

Cited by 34 publications

(22 citation statements)

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“…Brønsted acidity is observed on the oxides of high oxidation state elements. Among these elements, hexavalent tungsten is reported to give rise to stable, very acidic catalytic materials active as catalysts of several acid-catalyzed processes, including alcohol dehydration reactions [21][22][23][24][25]. In particular, tungsta-zirconias represent very interesting acid catalysts, already developed at the industrial level for paraffin isomerization [26], but the reasons of their high activity has not been fully clarified [27,28].…”

Section: Introductionmentioning

confidence: 99%

Conversion of ethanol over transition metal oxide catalysts: Effect of tungsta addition on catalytic behaviour of titania and zirconia

Phung

Hernández

Busca

2015

Applied Catalysis A: General

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Section: Introductionmentioning

confidence: 99%

Conversion of ethanol over transition metal oxide catalysts: Effect of tungsta addition on catalytic behaviour of titania and zirconia

Phung

Hernández

Busca

2015

Applied Catalysis A: General

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“…Niobium silicate 8 or silicotungstic acid supported on mesoporous silica 3 have been reported to show good selectivity for C2 = formation, but the reaction rates are not high due to the low surface areas. In addition, the low stability of loaded active components under high partial pressure of water would be a disadvantage for practical use.…”

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confidence: 99%

“…M41 was prepared in the reported manner by using C 12 H 25 N(CH 3 ) 3 Br as the template and colloidal silica as the silica source.…”

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confidence: 99%

Fast and Quantitative Dehydration of Lower Alcohols to Corresponding Olefins on Mesoporous Silica Catalyst

2011

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Ethanol, 1-propanol, 2-propanol, and 1-butanol were quantitatively dehydrated to the corresponding olefins on mesoporous silica MCM-41 catalyst. The reaction rates were high and no deactivation was observed for 50 h. Two reaction routes were suggested: the intermolecular dehydration of alcohol and subsequent decomposition of ether and the direct dehydration of alcohol.Utilization of bioethanol (bEtOH) as alternative to or as an additive of automobile fuel has rapidly expanded all over the world. This is of course a way to use renewable resources and suppress carbon dioxide emission, while another challenge is the conversion of bEtOH to various olefins and their use for production of chemicals and polymers.1 The latter would be very significant to fix carbon dioxide for the long-term period. Many efforts have, therefore, been devoted to development of selective conversion systems of bEtOH to ethene (C2 = ). It is widely known that the dehydration of alcohols is well catalyzed on various types of acids including modified aluminas, 2 supported heteropolyacids, 3 zeolites, 48 mesoporous materials, 9 and others, 10 but the activity and selectivity reported so far have been insufficient. For example, the reaction rates and the selectivity of C2 = on proton-or metal-modified zeolites should be improved, the selectivity is often restricted to ca. 96% due to strong acidic sites which cause oligomerization, polymerization, and fission of the produced lower olefins. 5,6 The various reactions in the zeolite pores finally result in coke formation and short lifetime. 57Niobium silicate 8 or silicotungstic acid supported on mesoporous silica 3 have been reported to show good selectivity for C2 = formation, but the reaction rates are not high due to the low surface areas. In addition, the low stability of loaded active components under high partial pressure of water would be a disadvantage for practical use.The novel acidic properties of mesoporous silica material, MCM-41 (M41), have been reported from the present 11,12 and other groups. 13 The acidity is not strong but unique to promote various selective catalyses. Our efforts have, therefore, been devoted to revealing the catalytic activity of M41 for the dehydration of EtOH, 1-and 2-propanol (PrOH), and 1-butanol (BuOH) to C2 = , propene (C3 = ), and butenes (C4 = ). We found the fast, quantitative, and stable catalyst can solve the above problems. The catalytic dehydration of alcohols is well known to be an easy heterogeneous catalytic reaction, but quantitative progress without deactivation is still necessary.M41 was prepared in the reported manner by using C 12 H 25 N(CH 3 ) 3 Br as the template and colloidal silica as the silica source.14 After calcination of M41 at 873 K for 6 h in air, the BET surface area and the BJH pore diameter determined by a N 2 adsorption measurement were 1010 m 2 g ¹1 and 2.12 nm, respectively. The hexagonal structure of resulting M41 was confirmed by appearance of 2ª = 2.580, 4.476, and 5.124 degree peaks in X-ray diffraction patterns (Cu K¡, ...

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“…Pt-Sn incorporated mesoporous silicate materials were prepared in two groups; in the first group, MCM-41 that was prepared following the one-pot hydrothermal synthesis procedure presented by Varisli et al (2009Varisli et al ( , 2010, was used as a support for Pt and Sn. In the second group of catalysts, instead of MCM-41, Sn incorporated mesoporous silicate material, namely Sn-SiO 2 , was prepared by onepot hydrothermal synthesis procedure and it was used as a support for Pt.…”

Section: Catalyst Synthesis and Characterizationmentioning

confidence: 99%

Synthesis and Characterization of Pt-Sn Incorporated MCM-41 and Pt Incorporated Sn-SiO2 Type Mesoporous Catalysts for Direct Ethanol Fuel Cell

Varışlı¹,

Rona²,

Tapan³

2010

International Journal of Chemical Reactor Engineering

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In this study, Pt-Sn incorporated mesoporous silicate materials were synthesized and characterized, and their activities in ethanol electro-oxidation reaction were tested by cyclic voltammetry. Two groups of catalysts were prepared. In the first group, Pt@MCM-41 and Pt-Sn@MCM-41 were prepared by impregnation of Pt and Sn onto MCM-41 support, which was synthesized by one-pot hydrothermal synthesis method. We adjusted the Pt/Sn molar ratio of 2 in the synthesis solution, and the Pt-Sn alloy formation was recognized beside large platinum particles for Pt-Sn@MCM-41. In the second group of catalysts, Sn-SiO 2 was prepared by one-pot hydrothermal synthesis procedure with a Sn/Si molar ratio of 0.014 and was used as support material for Pt. Tin oxide phase was well dispersed through silicate structure and only large Pt particles were found in the XRD analysis of Pt@Sn-SiO 2 , in which the Pt/Sn ratio was 2. In order to see the effect of Pt/Sn molar ratio on the structural and catalytic activity of the catalyst, Pt@Sn-SiO 2 (3:2) was prepared by changing the Pt/Sn ratio to 3/2 and obtaining smaller particles for the later one. After electrochemical activity tests in 0.5M H 2 SO 4 and 0.5M H 2 SO 4 + 0.5M C 2 H 5 OH electrolyte environments, it was seen that Pt@MCM-41, Pt-Sn@MCM-41, Pt-@Sn-SiO 2 (3:2) and Pt@Sn-SiO 2 , exhibit different ethanol electro-oxidation behavior, which is assumed to be due to different pore and crystalline size. Sn-SiO 2 supported Pt showed the highest oxidation currents after 0.6V vs. RHE. An ethanol oxidation behavior of Pt@Sn-SiO 2 (3:2) and polycrystalline Pt was very close at 0.6V vs. RHE.

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Novel Mesoporous Nanocomposite WO_x-Silicate Acidic Catalysts: Ethylene and Diethylether from Ethanol

Cited by 34 publications

References 34 publications

Conversion of ethanol over transition metal oxide catalysts: Effect of tungsta addition on catalytic behaviour of titania and zirconia

Conversion of ethanol over transition metal oxide catalysts: Effect of tungsta addition on catalytic behaviour of titania and zirconia

Fast and Quantitative Dehydration of Lower Alcohols to Corresponding Olefins on Mesoporous Silica Catalyst

Synthesis and Characterization of Pt-Sn Incorporated MCM-41 and Pt Incorporated Sn-SiO2 Type Mesoporous Catalysts for Direct Ethanol Fuel Cell

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Novel Mesoporous Nanocomposite WOx-Silicate Acidic Catalysts: Ethylene and Diethylether from Ethanol

Cited by 34 publications

References 34 publications

Conversion of ethanol over transition metal oxide catalysts: Effect of tungsta addition on catalytic behaviour of titania and zirconia

Conversion of ethanol over transition metal oxide catalysts: Effect of tungsta addition on catalytic behaviour of titania and zirconia

Fast and Quantitative Dehydration of Lower Alcohols to Corresponding Olefins on Mesoporous Silica Catalyst

Synthesis and Characterization of Pt-Sn Incorporated MCM-41 and Pt Incorporated Sn-SiO2 Type Mesoporous Catalysts for Direct Ethanol Fuel Cell

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Novel Mesoporous Nanocomposite WO_x-Silicate Acidic Catalysts: Ethylene and Diethylether from Ethanol