Understanding the roles of different acid sites in Beta zeolites with different particle sizes catalyzed liquid-phase transalkylation of diethylbenzene with benzene

2021 ◽  
Author(s):  
Chuanyu Yang ◽  
Zhongwen Dong ◽  
Weifeng Chu ◽  
Yanan Wang ◽  
Dongpu Zhao ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Beta Zeolite ◽  
Particle Sizes ◽  
Synthesis System ◽  
Beta Zeolites

A series of Beta zeolite catalysts with controllable particle sizes and similar Si/Al ratios were prepared by introducing imidazole (IMD) into the synthesis system and used for a liquid-phase transalkylation...

scholarly journals Mesoporous Beta Zeolite Catalysts for Benzylation of Naphthalene: Effect of Pore Structure and Acidity

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 504 ◽  
Author(s):  
Wenming Hao ◽  
Weimin Zhang ◽  
Zaibin Guo ◽  
Jinghong Ma ◽  
Ruifeng Li
Keyword(s):  
Catalytic Performance ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Beta Zeolite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Type ◽  
Beta Zeolites ◽  
Acidic Sites ◽  
Xrd Patterns

To improve the catalytic performance of zeolite catalysts in reactions involving bulky molecules, a series of mesoporous Beta zeolite were prepared using organic functionalized fumed silica as the silicon source, which were thoroughly characterized in terms of porosity and acidity. The peaks in X-ray diffraction (XRD) patterns showed broadening, and the external surface area and mesoporosity increased progressively when the content of organic functionalization increased. An infrared (IR) spectroscopy study of adsorbed probe molecules, including pyridine (Py-IR), 2,6-ditertbutylpyridine (DTBPy-IR) and pivalonitrile (Pn-IR), showed that the improvement of mesoporosity increased the accessibility of acidic sites. In the catalytic benzylation of naphthalene with benzyl chloride (BC) over the mesoporous Beta zeolite catalysts, the conversion of BC was significantly increased when the accessibility of Brönsted acid sites improved. The increase of mesoporosity not only improved the diffusion ability of the reactants and products, but also increased the accessibility of acid sites, which greatly enhanced the activity of the mesoporous Beta zeolite catalysts. It is highlighted that the interdependence of mesoporosity, acid type, acid concentration, and strength of the mesoporous Beta zeolites on the catalytic performance in the benzylation of naphthalene with BC was comprehensively studied.

Hydroisomerization in liquid phase of a refinery naphtha stream over Pt–Ni/H-beta zeolite catalysts

2008 ◽  
Vol 136 (2-3) ◽  
pp. 267-275 ◽  
Author(s):  
Antonia Fúnez ◽  
Antonio De Lucas ◽  
Paula Sánchez ◽  
María Jesús Ramos ◽  
José Luís Valverde
Keyword(s):  
Liquid Phase ◽  
Zeolite Catalysts ◽  
Beta Zeolite

scholarly journals Deactivation of Zeolite Catalysts in the Prins Reaction between Propene and Formaldehyde in the Liquid Phase

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1181
Author(s):  
Stanislav P. Bedenko ◽  
Konstantin I. Dement’ev ◽  
Valentin F. Tret’yakov
Keyword(s):  
Liquid Phase ◽  
Kinetic Model ◽  
Pore Diameter ◽  
Product Distribution ◽  
Acid Sites ◽  
Weak Acid ◽  
Zeolite Catalysts ◽  
Prins Reaction ◽  
Acidic Properties ◽  
Deactivation Process

The Prins reaction between propene and formaldehyde was studied over H-BEA, H-FAU, H-MFI and H-MOR zeolites at 150 °C in liquid phase. It was found that the H-BEA sample is the most active and selective toward buta-1,3-diene; the H-MFI is a potential catalyst for 3-buten-1-ol synthesis, while H-FAU can be used for 4-methyl-1,3-dioxane production. It had been confirmed that zeolite textural and acidic properties influence catalyst behaviour: the acidic properties influence sample activity, while product distribution is controlled by pore volume and effective pore diameter. The sample’s deactivation process had been studied and the kinetic model of deactivation was proposed. It was shown that the deactivation rate for the H-MFI catalyst is four times greater than for the H-BEA catalyst, probably because its strong/weak acid sites ratio is much more high than for the H-BEA.

Facile Preparation of a Binderless Hierarchical Beta Zeolite in Shaped Form and with Improved Acidity for Catalysis

2020 ◽  
Author(s):  
Jiaxu Liu ◽  
Zhenmei Zhang ◽  
Chunyan Liu ◽  
Gianvito Vilé ◽  
Guang Xiong ◽  
...  
Keyword(s):  
Materials Science ◽  
Zeolite Catalysts ◽  
Beta Zeolite ◽  
Synthetic Approach ◽  
Advanced Manufacturing ◽  
Hierarchical Zeolite ◽  
Characterization Methods ◽  
Tetraethylammonium Hydroxide ◽  
Beta Zeolites ◽  
Structure Properties

<div> <div> <div> <div> <p>The synthesis of a technical hierarchical nanosized zeolite catalysts without growth modifiers and binders remains a major challenge in catalysis. Herein, we report a new synthetic approach to directly produce hierarchical nanosized Beta zeolites in technical form, without any binders in the final material. The synthesis consists of two steps, where a Beta zeolite powder is first shaped using tetraethyl orthosilicate; the extrude is then recrystallized at high temperature in the presence of tetraethylammonium hydroxide solution. This transforms the SiO2 binders into zeolite framework. A variety of characterization methods were applied to unlock structure-properties relationships of the materials and demostrate their catalytic functionality. We believe that this work opens avenues for the advanced manufacturing of hierarchical zeolite materials in shaped form, and will find useful applications in catalysis and materials science. </p> </div> </div> </div> </div>

Facile Preparation of a Binderless Hierarchical Beta Zeolite in Shaped Form and with Improved Acidity for Catalysis

2020 ◽  
Author(s):  
Jiaxu Liu ◽  
Zhenmei Zhang ◽  
Chunyan Liu ◽  
Gianvito Vilé ◽  
Guang Xiong ◽  
...  
Keyword(s):  
Materials Science ◽  
Zeolite Catalysts ◽  
Beta Zeolite ◽  
Synthetic Approach ◽  
Advanced Manufacturing ◽  
Hierarchical Zeolite ◽  
Characterization Methods ◽  
Tetraethylammonium Hydroxide ◽  
Beta Zeolites ◽  
Structure Properties

<div> <div> <div> <div> <p>The synthesis of a technical hierarchical nanosized zeolite catalysts without growth modifiers and binders remains a major challenge in catalysis. Herein, we report a new synthetic approach to directly produce hierarchical nanosized Beta zeolites in technical form, without any binders in the final material. The synthesis consists of two steps, where a Beta zeolite powder is first shaped using tetraethyl orthosilicate; the extrude is then recrystallized at high temperature in the presence of tetraethylammonium hydroxide solution. This transforms the SiO2 binders into zeolite framework. A variety of characterization methods were applied to unlock structure-properties relationships of the materials and demostrate their catalytic functionality. We believe that this work opens avenues for the advanced manufacturing of hierarchical zeolite materials in shaped form, and will find useful applications in catalysis and materials science. </p> </div> </div> </div> </div>

scholarly journals Hydrodemethoxylation/Dealkylation on Bifunctional Nanosized Zeolite Beta

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7694
Author(s):  
Margarita Popova ◽  
Ágnes Szegedi ◽  
Manuela Oykova ◽  
Hristina Lazarova ◽  
Neli Koseva ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Structural Changes ◽  
Synthesis Method ◽  
Ruthenium Oxide ◽  
Acid Sites ◽  
Zeolite Catalysts ◽  
Beta Zeolite ◽  
Nickel Ions ◽  
Ft Ir

Mono-, and bimetallic Ni-, Ru-, and Pt-modified nanosized Beta zeolite catalysts were prepared by the post synthesis method and characterized by powder X-ray diffraction (XRD), nitrogen physisorption, HRTEM microscopy, temperature-programmed reduction (TPR-TGA), ATR FT-IR spectroscopy, and by solid-state MAS-NMR spectroscopy. The presence of nanosized nickel-oxide, ruthenium-oxide, and platinum species was detected on the catalysts. The presence of Brønsted and Lewis acid sites, and incorporation of nickel ions into zeolite lattice was proven by FT-IR of adsorbed pyridine. The structural changes in the catalyst matrix were investigated by solid state NMR spectroscopy. The catalysts were used in a gas-phase hydrodemethoxylation and dealkylation of 2-methoxy-4-propylphenol as a lignin derivative molecule for phenol synthesis.

scholarly journals Effect of Alkali-Free Synthesis and Post-Synthetic Treatment on Acid Sites in Beta Zeolites

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3434
Author(s):  
Kinga Mlekodaj ◽  
Joanna E. Olszowka ◽  
Venceslava Tokarova ◽  
Edyta Tabor ◽  
Ales Kasparek ◽  
...  
Keyword(s):  
Total Concentration ◽  
Textural Properties ◽  
Acid Sites ◽  
Beta Zeolite ◽  
Synthesis Methods ◽  
Channel System ◽  
Beta Zeolites ◽  
Amorphous Aluminosilicate ◽  
Standard Beta ◽  
Brønsted And Lewis Acid

Beta zeolites with Si/Al around 14 were prepared using three new alkali-free synthesis methods based on the application of amorphous aluminosilicate precursor and calcined in ammonia or air. All samples exhibit structural and textural properties of standard beta zeolite. Comprehensive study by 27Al and 29Si MAS NMR, together with FTIR adsorption of d3-acetonitrile and pyridine were used to characterize the influence of both the synthesis and calcination procedure on the framework Al atoms and related Brønsted and Lewis acid sites. While calcination in ammonia preserves all framework Al atoms, calcination in air results in 15% release of framework Al, but without restrictions of the accessibility of the beta zeolite channel system for bulky pyridine molecules. Terminal (SiO)3AlOH groups present in the hydrated zeolites were suggested as a precursor of framework Al-Lewis sites. Surprisingly, the mild dealumination of the air-calcined zeolites result in an increase of the concentration of Brønsted acid sites and a decrease of the total concentration of Lewis sites with the formation of the extra-framework ones.

Influence of Natural and H-Beta Zeolites on Yield and Composition of Non-Polar Fraction of Bio-Oil in Slow Co-Pyrolysis of Biomass and Polypropylene

2020 ◽  
Vol 849 ◽  
pp. 34-39
Author(s):  
Dijan Supramono ◽  
Syafira Tiaradiba
Keyword(s):  
Synergistic Effect ◽  
Natural Zeolite ◽  
Polar Fraction ◽  
Zeolite Catalysts ◽  
Beta Zeolite ◽  
Beta Zeolites ◽  
Bio Oil ◽  
Commercial Gasoline ◽  
Combined Feed ◽  
Pyrolysis Of Biomass

The non-oxygenated fraction of bio-oil is precursor of the formation of biofuel because it contains hydrocarbon only. Zeolite catalysts have been proved to improve the yields of non-polar fraction of bio-oil in case of fast co-pyrolysis. In the present work, the catalysts were applied to slow co-pyrolysis to investigate their effect on the yields and compositions of non-oxygenated fractions of bio-oil. The co-pyrolysis was conducted in a stirred tank reactor using non catalyst (thermal co-pyrolysis), natural zeolite and H-beta zeolite catalysts with heating rate of 5°C/minute from ambient temperature to 500°C and PP composition in combined feed varied 0, 50, and 100% weight of PP. As biomass, the present study used corn cobs. The results show that synergistic effect on the yield of non-oxygenated fraction in co-pyrolysis involving natural zeolite was lower than that in thermal co-pyrolysis and co-pyrolysis involving H-beta-zeolite exhibited negative synergistic effect. H-NMR analysis of the fraction from co-pyrolysis involving 50% weight of PP shows that the bio-oil contained approximately methyl H of about 55% by mol, methine H of 20% and methylene H of about 15% irrespective of catalysts used. This composition was closer to that of commercial gasoline rather than commercial diesel compositions.

Enhanced Activity of Nanocrystalline Beta Zeolite for Acylation of Veratrole with Acetic Anhydride

2016 ◽  
Vol 16 (4) ◽  
pp. 4247-4251
Author(s):  
Aisha Mahmood Abdulkareem Al-Turkustani ◽  
Rosilda Selvin
Keyword(s):  
Acetic Anhydride ◽  
Zeolite Catalyst ◽  
Structural Features ◽  
Systematic Investigation ◽  
Beta Zeolite ◽  
Particle Sizes ◽  
Solid Catalysts ◽  
Beta Zeolites ◽  
Homogeneous Acid ◽  
Heterogeneous Solid

Friedel-Craft acylation of veratrole using homogeneous acid catalysts such as AlCl3, FeCl3, ZnCl2, and HF etc. produces acetoveratrone, (3’,4’-dimethoxyacetophenone), which is the intermediate for synthesis of papavarine alkaloids. The problems associated with these homogeneous catalysts can be overcome by using heterogeneous solid catalysts. Since acetoveratrone is a larger molecule, large pore Beta zeolites with smaller particle sizes are beneficial for the liquid-phase acylation of veratrole, for easy diffusion of reactants and products. The present study aims in the acylation of veratrole with acetic anhydride using nanocrystalline Beta Zeolite catalyst. A systematic investigation of the effects of various reaction parameters was done. The catalysts were characterized for their structural features by using XRD, TEM and DLS analyses. The catalytic activity of nanocrystalline Beta zeolite was compared with commercial Beta zeolite for the acylation and was found that nanocrystalline Beta zeolite possessed superior activity.

Rapid, Non-Toxic Synthesis of Beta Zeolites

2018 ◽  
Author(s):  
Felix Hemmann ◽  
Jonathan Hackebeil ◽  
Andreas Lißner ◽  
Florian Mertens
Keyword(s):  
Hydrofluoric Acid ◽  
Molecular Sieves ◽  
Toxic Chemicals ◽  
Lewis Acidity ◽  
Beta Zeolite ◽  
Seeded Growth ◽  
Related Research ◽  
Beta Zeolites ◽  
Growth Method ◽  
Fast Synthesis

Molecular sieves with beta zeolite topology are promising catalysts for various reactions as they exhibits extraordinary Lewis acidity. However, their industrial application and related research in academica is hindered because their synthesis is time consuming and typically involves toxic chemicals as hydrofluoric acid. Therefore, tetraethylammonium fluorid was tested as a non-toxic fluotide source for the synthesis of beta zeolites. In combination with the previously reported nano-seeded growth method, a fast synthesis of beta zeolites only involving non-toxic chemicals was possible. Synthesized zeolites show comparable selectivity in the Bayer-Villinger oxidation as conventional zeolites synthesized with hydrofluoric acid.<br>

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