Influence of the Incorporation of Basic or Amphoteric Oxides on the Performance of Cu-Based Catalysts Supported on Sepiolite in Furfural Hydrogenation

Cu-based catalysts supported on sepiolite have been tested in vapor-phase hydrogenation of furfural. The incorporation of basic or amphoteric metal oxides (magnesium oxide, zinc oxide, or cerium oxide) improves the catalytic behavior, reaching a maximum furfural conversion above 80% after 5 h of reaction at 210 °C. In all cases, the main product is furfuryl alcohol, obtaining 2-methylfuran in lower proportions. The incorporation of these metal oxide species ameliorates the dispersion of metallic Cu nanoparticles, increasing the number of available Cu0-sites, which enhances the catalytic performance. The presence of acid sites favors the hydrogenolysis of furfuryl alcohol towards 2-methylfuran, although it also causes an increase of carbon species on its surface, which is associated with the catalytic deactivation of the catalyst along the time-on-stream.

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Synthesis and Catalytic Application of Mesoporous Molecular Sieves MCM-41 Containing Niobium and Tantalum

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.1761 ◽

2007 ◽

Vol 124-126 ◽

pp. 1761-1764 ◽

Cited By ~ 3

Author(s):

Hun Jung ◽

Kwang Deog Jung ◽

Oh Shim Joo ◽

Sun Jin Kim

Keyword(s):

Vapor Phase ◽

Molecular Sieves ◽

Catalytic Performance ◽

Acid Sites ◽

Weak Acid ◽

Beckmann Rearrangement ◽

Mesoporous Molecular Sieves ◽

Cyclohexanone Oxime ◽

Catalytic Application ◽

Mcm 41

Niobium- and tantalum-containing mesoporous molecular sieves MCM-41 have been synthesized, and applied as a catalyst for vapor phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam. NbMCM-41 catalyst exhibited high catalytic performance in the vapor phase Beckmann rearrangement of cyclohexanone oxime. The oxime conversions were almost 100% and the lactam selectivities were around 80%. The lactam selectivities of NbMCM-41 catalyst were higher than those of AlMCM-41 catalyst. However, TaMCM-41 catalyst exhibited lower catalytic performance than AlMCM-41 catalyst, and it was fast deactivated with time. These results may be due to the acidity difference among the catalysts. The results from NH3-TPD showed that NbMCM-41 catalyst possessed weak and medium acid sites, while TaMCM-41 catalyst possessed only very weak acid sites. AlMCM-41 catalyst also exhibited only weak acid sites.

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Catalytic Behavior of Alkali Treated H-MOR in Selective Synthesis of Ethylenediamine via Condensation Amination of Monoethanolamine

Catalysts ◽

10.3390/catal10040386 ◽

2020 ◽

Vol 10 (4) ◽

pp. 386

Author(s):

Feng-Wei Zhao ◽

Qian Zhang ◽

Feng Hui ◽

Jun Yuan ◽

Su-Ning Mei ◽

...

Keyword(s):

Electron Microscopy ◽

Active Sites ◽

Alkali Treatment ◽

Catalytic Performance ◽

Acid Sites ◽

Selective Synthesis ◽

Catalytic Behavior ◽

X Ray ◽

Bulk Catalyst ◽

Temperature Programmed

Catalytic behavior of alkali treated mordenite (H-MOR) in selective synthesis of ethylenediamine (EDA) via condensation amination of monoethanolamine (MEA) was investigated. Changes in the structural and acidic properties of alkali treated H-MOR were systematically investigated by N2 adsorption/desorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), temperature programmed ammonia desorption (NH3-TPD), pyridine adsorption was followed by infrared spectroscopy (Py-IR), and X-ray fluorescence (XRF) analyses. The results show that alkali treatment produces more opening mesopores on the H-MOR crystal surfaces and leads to an increase in the number of B acid sites and the strength of the acid sites. The mesopores effectively enhance the rate of diffusion in the bulk catalyst. Moreover, the B acid sites are active sites in selective synthesis of EDA. Due to improvements in the diffusion conditions and reactivities, alkali treated H-MOR shows an excellent catalytic performance under mild reaction conditions. The conversion of MEA was 52.8% and selectivity to EDA increased to 93.6%, which is the highest selectivity achieved so far. Furthermore, possible mechanism for the formation of EDA is discussed.

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Furfural Hydrogenation on Modified Niobia

Applied Sciences ◽

10.3390/app9112287 ◽

2019 ◽

Vol 9 (11) ◽

pp. 2287 ◽

Cited By ~ 3

Author(s):

Andrea Jouve ◽

Stefano Cattaneo ◽

Daniel Delgado ◽

Nicola Scotti ◽

Claudio Evangelisti ◽

...

Keyword(s):

Catalytic Activity ◽

Lewis Acid ◽

Furfuryl Alcohol ◽

Surface Acidity ◽

High Surface ◽

Pt Nanoparticles ◽

Acid Sites ◽

High Catalytic Activity ◽

Lewis Acid Sites ◽

Furfural Hydrogenation

In this study, niobia-based materials have been used as supports for Pt nanoparticles and used in the hydrogenation of furfural. The incorporation of dopants (W6+ and Ti4+) in the Nb2O5 structure induced modifications in the surface acidity of the support; in particular, the addition of W6+ increased the amount of Lewis acid sites, while the addition of Ti4+ decreased the number of Lewis acid sites. As a result, the catalytic activity towards the hydrogenation of furfural was affected; high surface acidity resulted in high catalytic activity. The selectivity of the reaction changed with the support acidity as well, with higher amount of furfuryl alcohol produced decreasing the Lewis acid sites.

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Insight into Active Centers and Anti-Coke Behavior of Niobium-Containing SBA-15 for Glycerol Dehydration

Catalysts ◽

10.3390/catal11040488 ◽

2021 ◽

Vol 11 (4) ◽

pp. 488

Author(s):

Katarzyna Stawicka ◽

Maciej Trejda ◽

Maria Ziolek

Keyword(s):

Coke Formation ◽

Catalytic Performance ◽

Acid Sites ◽

Silica Matrix ◽

High Concentration ◽

Active Centers ◽

Acidic Sites ◽

Glycerol Dehydration ◽

Adsorption Desorption ◽

Insight Into

Niobium containing SBA-15 was prepared by two methods: impregnation with different amounts of ammonium niobate(V) oxalate (Nb-15/SBA-15 and Nb-25/SBA-15 containing 15 wt.% and 25 wt.% of Nb, respectively) and mixing of mesoporous silica with Nb2O5 followed by heating at 500 °C (Nb2O5/SBA-15). The use of these two procedures allowed obtaining materials with different textural/surface properties determined by N2 adsorption/desorption isotherms, XRD, UV-Vis, pyridine, and NO adsorption combined with FTIR spectroscopy. Nb2O5/SBA-15 contained exclusively crystalline Nb2O5 on the SBA-15 surface, whereas the materials prepared by impregnation had both metal oxide and niobium incorporated into the silica matrix. The niobium species localized in silica framework generated Brønsted (BAS) and Lewis (LAS) acid sites. The inclusion of niobium into SBA-15 skeleton was crucial for the achievement of high catalytic performance. The strongest BAS were on Nb-25/SBA-15, whereas the highest concentration of BAS and LAS was on Nb-15/SBA-15 surface. Nb2O5/SBA-15 material possessed only weak LAS and BAS. The presence of the strongest BAS (Nb-25/SBA-15) resulted in the highest dehydration activity, whereas a high concentration of BAS was unfavorable. Silylation of niobium catalysts prepared by impregnation reduced the number of acidic sites and significantly increased acrolein yield and selectivity (from ca. 43% selectivity for Nb-25/SBA-15 to ca. 61% for silylated sample). This was accompanied by a considerable decrease in coke formation (from 47% selectivity for Nb-25/SBA-15 to 27% for silylated material).

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Reaction Mechanism for CCl2F2 Catalytic Decomposition over MoO3/ZrO2

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.295-298.326 ◽

2013 ◽

Vol 295-298 ◽

pp. 326-330 ◽

Cited By ~ 3

Author(s):

Tian Cheng Liu ◽

Yu Jiao Guo ◽

Ping Ning ◽

Ming Long Yuan

Keyword(s):

Reaction Mechanism ◽

Main Product ◽

Solid Acid ◽

Fixed Bed ◽

Catalytic Decomposition ◽

Strong Acid ◽

Acid Sites ◽

Fixed Bed Reactor ◽

Surface Intermediate ◽

Strong Acid Sites

Catalytic hydrolysis decomposition of dichlorodifluoromethane (CCl2F2) in the presence of water vapor and oxygen was studied over a series of solid acids using a fixed-bed reactor. Solid acid MoO3/ZrO2 displayed the highest activity, over which the conversion of CCl2F2 reached 100 % at 250 °C. CO2 was the main-product and the selectivity to CClF3 remained lower than 28.0 %. CO was not detected as by-product. The decomposition activity depended on the calcination temperature and the ZrO2 content. The activity of solid acid MoO3/ZrO2 correlates well with its specific surface area and the amount of medium-strong acid sites on the surface. To explain the reaction mechanism for CCl2F2 catalytic decomposition over MoO3/ZrO2, a surface intermediate, Osurface-CF2-Osurface is proposed.

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Tuning the Reaction Selectivity over MgAl Spinel-Supported Pt Catalyst in Furfuryl Alcohol Conversion to Pentanediols

Catalysts ◽

10.3390/catal11040415 ◽

2021 ◽

Vol 11 (4) ◽

pp. 415

Author(s):

Xinsheng Li ◽

Jifeng Pang ◽

Jingcai Zhang ◽

Xianquan Li ◽

Yu Jiang ◽

...

Keyword(s):

Furfuryl Alcohol ◽

Pt Nanoparticles ◽

Catalytic Performance ◽

Major Product ◽

Pt Catalyst ◽

Reaction Products ◽

Strong Base ◽

Reaction Selectivity ◽

Supported Pt Catalysts ◽

Alcohol Conversion

Catalytic conversion of biomass-derived feedstock to high-value chemicals is of remarkable significance for alleviating dependence on fossil energy resources. MgAl spinel-supported Pt catalysts were prepared and used in furfuryl alcohol conversion. The approaches to tune the reaction selectivity toward pentanediols (PeDs) were investigated and the catalytic performance was correlated to the catalysts’ physicochemical properties based on comprehensive characterizations. It was found that 1–8 wt% Pt was highly dispersed on the MgAl2O4 support as nanoparticles with small sizes of 1–3 nm. The reaction selectivity did not show dependence on the size of Pt nanoparticles. Introducing LiOH onto the support effectively steered the reaction products toward the PeDs at the expense of tetrahydrofurfuryl alcohol (THFA) selectivity. Meanwhile, the major product in PeDs was shifted from 1,5-PeD to 1,2-PeD. The reasons for the PeDs selectivity enhancement were attributed to the generation of a large number of medium-strong base sites on the Li-modified Pt catalyst. The reaction temperature is another effective factor to tune the reaction selectivity. At 230 °C, PeDs selectivity was enhanced to 77.4% with a 1,2-PeD to 1,5-PeD ratio of 3.7 over 4Pt/10Li/MgAl2O4. The Pt/Li/MgAl2O4 catalyst was robust to be reused five times without deactivation.

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Ruling Factors in Cinnamaldehyde Hydrogenation: Activity and Selectivity of Pt-Mo Catalysts

Nanomaterials ◽

10.3390/nano11020362 ◽

2021 ◽

Vol 11 (2) ◽

pp. 362

Author(s):

Marta Stucchi ◽

Maela Manzoli ◽

Filippo Bossola ◽

Alberto Villa ◽

Laura Prati

Keyword(s):

Photoelectron Spectroscopy ◽

Pt Nanoparticles ◽

Carbon Support ◽

Catalytic Performance ◽

Acid Sites ◽

Hydrogenation Catalysts ◽

Cinnamaldehyde Hydrogenation ◽

Transmission Electron ◽

Heat Treated ◽

Heating Treatment

To obtain selective hydrogenation catalysts with low noble metal content, two carbon-supported Mo-Pt bimetallic catalysts have been synthesized from two different molybdenum precursors, i.e., Na2MoO4 and (NH4)6Mo7O24. The results obtained by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) combined with the presence and strength of acid sites clarified the different catalytic behavior toward cinnamaldehyde hydrogenation. After impregnating the carbon support with Mo precursors, each sample was used either as is or treated at 400 °C in N2 flow, as support for Pt nanoparticles (NPs). The heating treatment before Pt deposition had a positive effect on the catalytic performance. Indeed, TEM analyses showed very homogeneously dispersed Pt NPs only when they were deposited on the heat-treated Mo/C supports, and XPS analyses revealed an increase in both the exposure and reduction of Pt, which was probably tuned by different MoO3/MoO2 ratios. Moreover, the different acid properties of the catalysts resulted in different selectivity.

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High-efficiency catalytic performance over mesoporous Ni/beta zeolite for the synthesis of quinoline from glycerol and aniline

RSC Advances ◽

10.1039/c6ra26736j ◽

2017 ◽

Vol 7 (16) ◽

pp. 9551-9561 ◽

Cited By ~ 15

Author(s):

An Li ◽

Chen Huang ◽

Cai-Wu Luo ◽

Wen-Jun Yi ◽

Zi-Sheng Chao

Keyword(s):

Catalytic Activity ◽

Vapor Phase ◽

High Efficiency ◽

Zeolite Catalyst ◽

Catalytic Performance ◽

Beta Zeolite ◽

Phase Process

Quinoline was synthesized via the typical Skraup approach with a vapor-phase process. The mesoporous Ni/beta zeolite catalyst exhibited high-efficiency catalytic activity and an enhanced ability of anti-deactivation.

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