scholarly journals Shape Selectivity in the Conversion of Methanol to Hydrocarbons: The Catalytic Performance of One-Dimensional 10-Ring Zeolites: ZSM-22, ZSM-23, ZSM-48, and EU-1

ACS Catalysis ◽  
2011 ◽  
Vol 2 (1) ◽  
pp. 26-37 ◽  
Author(s):  
Shewangizaw Teketel ◽  
Wegard Skistad ◽  
Sandrine Benard ◽  
Unni Olsbye ◽  
Karl Petter Lillerud ◽  
...  
Keyword(s):  
Shape Selectivity ◽  
Catalytic Performance ◽  
One Dimensional ◽  
Methanol To Hydrocarbons

scholarly journals Comparison in thermal stability and catalytic performance of H4PMo11VO40 heteropolyacid supported on mesoporous and macroporous silica materials

2020 ◽  
pp. 174751982092599
Author(s):  
Heng Zhang ◽  
Chunhao Yang ◽  
Shengying Zhao ◽  
Tingting Wang ◽  
Wancheng Zhu
Keyword(s):  
Thermal Stability ◽  
Active Sites ◽  
Catalytic Performance ◽  
High Dispersion ◽  
High Exposure ◽  
Macroporous Silica ◽  
One Dimensional ◽  
Ordered Macroporous ◽  
The One ◽  
Mcm 41

Ordered mesoporous silica, SBA-15 and MCM-41, and three-dimensionally ordered macroporous SiO2 were used as the supports of H4PMo11VO40 heteropolyacid for methacrolein oxidation. The dispersion and structural evolutions of the heteropolyacid along with thermal treatment were investigated. It was found that the heteropolyacid entered the one-dimensional mesoporous channels of SBA-15 and MCM-41, and the crystallization and growth were limited, leading to high dispersion of the heteropolyacid. However, the thermal stability was decreased under high dispersion. The migration of the heteropolyacid was observed to the end of the one-dimensional channels of SBA-15 and the outer surface of MCM-41 with calcination, accompanied by the decomposition of the heteropolyacid and the formation of MoO3. In comparison, the crystallization and growth of heteropolyacid were not limited in the open macropores of three-dimensionally ordered macroporous SiO2. Dispersed particles on the surface of the macropores with size of about 5 nm exhibited a higher thermal stability. The decomposition of the heteropolyacid in the SBA-15 and MCM-41 supported catalysts resulted in the loss of strong acid sites, causing low selectivity to methacrylic acid in methacrolein oxidation. High thermal stability with high exposure of the active sites in the three-dimensionally ordered macroporous SiO2 supported catalyst contributed to the enhancement in the catalytic performance.

scholarly journals Catalytic Activity of Polynuclear vs. Dinuclear Aroylhydrazone Cu(II) Complexes in Microwave-Assisted Oxidation of Neat Aliphatic and Aromatic Hydrocarbons

Molecules ◽  
2018 ◽  
Vol 24 (1) ◽  
pp. 47 ◽  
Author(s):  
Manas Sutradhar ◽  
Tannistha Barman ◽  
Armando Pombeiro ◽  
Luísa Martins
Keyword(s):  
Catalytic Activity ◽  
Aromatic Hydrocarbons ◽  
Catalytic Performance ◽  
Antiproliferative Agents ◽  
One Dimensional ◽  
X Ray ◽  
X Ray Crystallography ◽  
Mild Conditions ◽  
Microwave Assisted ◽  
Aliphatic And Aromatic Hydrocarbons

One-dimensional (1D) polynuclear Cu(II) complex (1) derived from (5-bromo-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L) is synthesized and characterized by elemental analysis, IR spectroscopy, ESI-MS, and single crystal X-ray crystallography. Its catalytic performance towards the solvent-free microwave-assisted peroxidative oxidation of aliphatic and aromatic hydrocarbons under mild conditions is compared with that of dinuclear Cu(II) complexes (2 and 3) of the same ligand, previously reported as antiproliferative agents. Polymer 1 exhibits the highest activity, either for the oxidation of cyclohexane (leading to overall yields, based on the alkane, of up to 39% of cyclohexanol and cyclohexanone) or towards the oxidation of toluene (selectively affording benzaldehyde up to a 44% yield), after 2 or 2.5 h of irradiation at 80 or 50 °C, respectively.

scholarly journals One Dimensional AuAg Nanostructures as Anodic Catalysts in the Ethylene Glycol Oxidation

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 719
Author(s):  
Daniel K. Kehoe ◽  
Luis Romeral ◽  
Ross Lundy ◽  
Michael A. Morris ◽  
Michael G. Lyons ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Ethylene Glycol ◽  
Catalytic Performance ◽  
Initial Reaction ◽  
Step Method ◽  
Power Sources ◽  
One Dimensional ◽  
Cell Technology ◽  
Fuel Cell Technology ◽  
Ethylene Glycol Oxidation

Direct alcohol fuel cells are highly promising as efficient power sources for various mobile and portable applications. However, for the further advancement of fuel cell technology it is necessary to develop new, cost-effective Pt-free electrocatalysts that could provide efficient alcohol oxidation and also resist cross-over poisoning. Here, we report new electrocatalytic materials for ethylene glycol oxidation, which are based on AuAg linear nanostructures. We demonstrate a low temperature tunable synthesis that enables the preparation of one dimensional (1D) AuAg nanostructures ranging from nanowires to a new nano-necklace-like structure. Using a two-step method, we showed that, by aging the initial reaction mixture at various temperatures, we produced ultrathin AuAg nanowires with a diameter of 9.2 ± 2 and 3.8 ± 1.6 nm, respectively. These nanowires exhibited a high catalytic performance for the electro-oxidation of ethylene glycol with remarkable poisoning resistance. These results highlight the benefit of 1D metal alloy-based nanocatalysts for fuel cell applications and are expected to make an important contribution to the further development of fuel cell technology.

scholarly journals Influence of Topology and Brønsted Acid Site Presence on Methanol Diffusion in Zeolites Beta and MFI

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1342
Author(s):  
Cecil Botchway ◽  
Richard Tia ◽  
Evans Adei ◽  
Alexander O’Malley ◽  
Nelson Dzade ◽  
...  
Keyword(s):  
Molecular Diffusion ◽  
Catalytic Performance ◽  
Acid Sites ◽  
Distribution Functions ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
A Value ◽  
Methanol To Hydrocarbons ◽  
Brönsted Acid ◽  
The Difference

Detailed insight into molecular diffusion in zeolite frameworks is crucial for the analysis of the factors governing their catalytic performance in methanol-to-hydrocarbons (MTH) reactions. In this work, we present a molecular dynamics study of the diffusion of methanol in all-silica and acidic zeolite MFI and Beta frameworks over the range of temperatures 373–473 K. Owing to the difference in pore dimensions, methanol diffusion is more hindered in H-MFI, with diffusion coefficients that do not exceed 10 × 10−10 m2s−1. In comparison, H-Beta shows diffusivities that are one to two orders of magnitude larger. Consequently, the activation energy of translational diffusion can reach 16 kJ·mol−1 in H-MFI, depending on the molecular loading, against a value for H-Beta that remains between 6 and 8 kJ·mol−1. The analysis of the radial distribution functions and the residence time at the Brønsted acid sites shows a greater probability for methylation of the framework in the MFI structure compared to zeolite Beta, with the latter displaying a higher prevalence for methanol clustering. These results contribute to the understanding of the differences in catalytic performance of zeolites with varying micropore dimensions in MTH reactions.

Chapter 6. Shape selectivity in zeolite catalysis. The Methanol to Hydrocarbons (MTH) reaction

Catalysis ◽  
2014 ◽  
pp. 179-217 ◽  
Author(s):  
Shewangizaw Teketel ◽  
Marius Westgård Erichsen ◽  
Francesca Lønstad Bleken ◽  
Stian Svelle ◽  
Karl Petter Lillerud ◽  
...  
Keyword(s):  
Shape Selectivity ◽  
Zeolite Catalysis ◽  
Methanol To Hydrocarbons

A new hexamolybdate-based copper–2,2′-biimidazole coordination polymer serving as an acid catalyst and support for enzyme immobilization

2018 ◽  
Vol 74 (11) ◽  
pp. 1362-1369
Author(s):  
Xiao-Jing Sang ◽  
Shu-Li Feng ◽  
Ying Lu ◽  
Yue-Xian Zhang ◽  
Fang Su ◽  
...  
Keyword(s):  
Coordination Polymer ◽  
Immobilized Enzyme ◽  
Hydrothermal Reaction ◽  
Three Dimensional ◽  
Acid Catalyst ◽  
Catalytic Performance ◽  
Crystalline Material ◽  
One Dimensional ◽  
Heterogeneous Acid Catalyst ◽  
Good Catalytic Activity

The hydrothermal reaction of (NH4)3[CoMo6O24H6]·7H2O (CoMo6 ), CuCl2·2H2O and 2,2′-biimidazole (H2biim) led to the formation of a new coordination polymer, namely poly[diaquabis(2,2′-biimidazole)hexa-μ3-oxo-octa-μ2-oxo-hexaoxodicopper(II)hexamolybdate(VI)], [Cu2Mo6O20(C6H6N4)2(H2O)2] n (Cu-Mo6O20 ), at pH 2–3. It is obvious that in the formation of crystalline Cu-Mo6O20 , the original Anderson-type skeleton of heteropolymolybdate CoMo6 was broken and the new isopolyhexamolybdate Mo6O20 unit was assembled. In Cu-Mo6O20 , one Mo6O20 unit connects four [Cu(H2biim)(H2O)]2+ ions in a pentacoordinate mode via four terminal O atoms, resulting in a tetra-supported structure, and each CuII ion is shared by two adjacent Mo6O20 units. Infinite one-dimensional chains are established by linkage between two adjacent Mo6O20 units and two CuII ions, and these chains are further packed into a three-dimensional framework by hydrogen bonds, π–π interactions and electrostatic attractions. The catalytic performance of this crystalline material used as an efficient and reusable heterogeneous acid catalyst for carbonyl-group protection is discussed. In addition, Cu-Mo6O20 was applied as a new support for enzyme (horseradish peroxidase, HRP) immobilization, forming immobilized enzyme HRP/Cu-Mo6O20 . HRP/Cu-Mo6O20 showed good catalytic activity and could be reused.

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