Catalytic ability of plasma heat-treated metal oxides on vapor-phase Beckmann rearrangement

Sugiyama, Kazuo; Anan, G; Shimada, T.; Ohkoshi, Tsuneo; Ushikubo, T.

doi:10.1016/s0257-8972(98)00783-x

Cited by 20 publications

(8 citation statements)

References 7 publications

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“…[6][7][8] Ushikubo et al were the first to publish the use of bulk tantalum and niobium oxides as catalysts for the GPBR. 9,10 Later on, catalyst materials containing niobia (e.g. Nb-MCM-41, Nb-SBA-15, Nb-beta and NbO x /SiO 2 ) were investigated by Hoelderich et al 11,12 In particular the niobia on silica catalyst material, i.e.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic study on the active site of a SiO₂ supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

Maronna

Kruissink

Parton

et al. 2016

Phys. Chem. Chem. Phys.

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NbOx/SiO2 with a very high catalytic activity for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam, was investigated by different spectroscopic methods in order to obtain new insights in the formation and nature of the active sites. FT-IR spectroscopy in combination with pyridine adsorption measurements revealed that the catalyst material contains Lewis-acidic sites, most probably related to the Nb[double bond, length as m-dash]O groups of isolated tetrahedral NbO4 surface species, whereas no Brønsted-acidic sites were observed. Results from in situ Raman and complementary FT-IR measurements strongly suggest that Brønsted-acidic Nb-OH sites can be generated from Nb[double bond, length as m-dash]O groups by reaction with ethanol. This is in agreement with the observation that ethanol is essential for obtaining a very good catalyst performance. However, the Brønsted-acidic sites can be detected in significant amounts in particular in the presence of a Lewis-base, e.g. pyridine, most probably because the formation and/or the stability of these Brønsted-acidic sites are enhanced by a basic molecule. Assuming that cyclohexanone oxime, being a base, can play a similar role as pyridine, we propose on the basis of the spectroscopic findings obtained in this work and our kinetic results published recently, a reaction scheme for the formation of the active site at the Nb[double bond, length as m-dash]O group as well as for the recovery of the Nb[double bond, length as m-dash]O site during the final stage of the gas-phase Beckmann rearrangement.

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Section: Introductionmentioning

confidence: 99%

Spectroscopic study on the active site of a SiO₂ supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

Maronna

Kruissink

Parton

et al. 2016

Phys. Chem. Chem. Phys.

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“…We previously utilized an Ar glow discharge plasma to treat supported metals in order to improve their catalytic performance. − We found that some metal ions exist in their metallic states after plasma treatment, which suggests that plasma treatment can reduce metal ions. It has also been reported that Nb 2 O 5 was partially reduced to Nb 4+ and Nb 2+ with microwave plasma treatment , which would be very attractive and promising because no reducing chemicals would be necessary.…”

Section: Introductionmentioning

confidence: 99%

Reduction of Supported Noble-Metal Ions Using Glow Discharge Plasma

2006

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A novel plasma reduction method has been developed to reduce supported noble-metal ions without the use of any reducing chemicals. H2PtCl6, PdCl2, AgNO3, and HAuCl4 supported on nonporous TiO2 and porous gamma-Al2O3 and HZSM-5 were reduced using an Ar glow discharge plasma. Optical absorption spectra and X-ray photoelectron spectroscopy show that the supported metal ions are completely reduced to metallic species. Transmission electron microscopy shows that the prepared metals are amorphous clusters and homogeneously distributed with nanoscale sizes. X-ray diffraction also confirms that the plasma-reduced metals exist as small crystallites or amorphous clusters. Thermal annealing of plasma-reduced samples at elevated temperature transforms the clusters into crystals with a slight increase in particle sizes, but the sizes are still smaller than those of H2-reduced metals. O2 glow discharge plasma can also reduce noble-metal ions, accompanied by production of a small amount of oxides. Plasma reduction is very promising for the preparation of metal nanoparticles and supported metal catalysts.

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“…S acrolein = n c−acrolein n c−gly−reacted × 100% (7) where S acrolein is the selectivity to acrolein (mol%), n c-acrolein is the moles of carbon in the produced acrolein, and n c-gly-reacted is the moles of carbon in the converted glycerol.…”

Section: Glycerol Dehydration To Acroleinmentioning

confidence: 99%

“…NTP treatment has been reported as a substitute for thermal calcination process of catalysts; significant reduction in treatment temperature and time and chemical activation were some of the major advantages of this novel approach [7]. Microwave NTP could introduce a certain level of local heating compared to other NTP techniques.…”

Section: Introductionmentioning

confidence: 99%

“…Microwave NTP could introduce a certain level of local heating compared to other NTP techniques. Sugiyama et al [7] used microwave NTP treatment to anneal a catalyst, and this catalyst improved the selectivity to the desired product, as compared to conventional calcination. This NTP annealing process also showed the advantage of reducing treatment time, providing similar or better reduction of metal oxide as compared to hours of conventional calcination [8].…”

Section: Introductionmentioning

confidence: 99%

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Nonthermal Plasma Induced Fabrication of Solid Acid Catalysts for Glycerol Dehydration to Acrolein

Liu

2021

Catalysts

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The feasibility of fabricating better solid acid catalysts using nonthermal plasma (NTP) technology for biobased acrolein production is demonstrated. NTP discharge exposure was integrated in catalyst fabrication in air or argon atmosphere. The fabricated catalysts were characterized by Brunauer–Emmett–Teller surface area analysis, temperature-programmed desorption of ammonia, X-ray powder diffraction and Fourier-transform infrared spectroscopy of pyridine adsorption, in comparison to regularly prepared catalysts as a control. Further, kinetic results collected via glycerol dehydration experiments were compared, and improvement in acrolein selectivity was displayed when the catalyst was fabricated in the argon NTP, but not in the air NTP. Possible mechanisms for the improvement were also discussed.

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Catalytic ability of plasma heat-treated metal oxides on vapor-phase Beckmann rearrangement

Cited by 20 publications

References 7 publications

Spectroscopic study on the active site of a SiO₂ supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

Spectroscopic study on the active site of a SiO₂ supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

Reduction of Supported Noble-Metal Ions Using Glow Discharge Plasma

Nonthermal Plasma Induced Fabrication of Solid Acid Catalysts for Glycerol Dehydration to Acrolein

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Catalytic ability of plasma heat-treated metal oxides on vapor-phase Beckmann rearrangement

Cited by 20 publications

References 7 publications

Spectroscopic study on the active site of a SiO2 supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

Spectroscopic study on the active site of a SiO2 supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

Reduction of Supported Noble-Metal Ions Using Glow Discharge Plasma

Nonthermal Plasma Induced Fabrication of Solid Acid Catalysts for Glycerol Dehydration to Acrolein

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Product

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Spectroscopic study on the active site of a SiO₂ supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam

Spectroscopic study on the active site of a SiO₂ supported niobia catalyst used for the gas-phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam