Modification of Y Zeolite with Alkaline Treatment: Textural Properties and Catalytic Activity for Diethyl Carbonate Synthesis

2013 ◽  
Vol 52 (19) ◽  
pp. 6349-6356 ◽  
Author(s):  
Shouying Huang ◽  
Pengzhen Chen ◽  
Bing Yan ◽  
Shengping Wang ◽  
Yongli Shen ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Textural Properties ◽  
Alkaline Treatment ◽  
Diethyl Carbonate ◽  
Y Zeolite

scholarly journals Effects of Different Variables on the Formation of Mesopores in Y Zeolite by the Action of CTA+ Surfactant

2018 ◽  
Vol 8 (8) ◽  
pp. 1299 ◽  
Author(s):  
Juliana Silva ◽  
Edilene Ferracine ◽  
Dilson Cardoso
Keyword(s):  
Active Sites ◽  
Cetyltrimethylammonium Bromide ◽  
Morphological Characteristics ◽  
Textural Properties ◽  
Alkaline Treatment ◽  
Y Zeolite ◽  
Usy Zeolite ◽  
Large Molecules ◽  
Structural Selectivity ◽  
Modified Zeolites

Zeolites are microporous crystalline aluminosilicates with a number of useful properties including acidity, hydrothermal stability, and structural selectivity. However, the exclusive presence of micropores restricts diffusive mass transport and reduces the access of large molecules to active sites. In order to resolve this problem, mesopores can be created in the zeolite, combining the advantages of microporous and mesoporous materials. In this work, mesospores were created in the Ultrastable USY zeolite (silicon/aluminum ratio of 15) using alkaline treatment (NaOH) in the presence of cetyltrimethylammonium bromide surfactant, followed by hydrothermal treatment. The effects of the different concentrations of NaOH and the surfactant on the textural, chemical, and morphological characteristics of the modified zeolites were evaluated. Generating mesoporosity in the USY zeolite was possible through the simultaneous presence of surfactant and alkaline solution. Among the parameters studied, the concentration of the alkaline medium had the greatest influence on the textural properties of the zeolites. The presence of Cetyltrimethylammonium Bromide (CTA+) prevented the amorphization of the structure during the modification and also avoided desilication of the zeolite.

Transformation of methanol to hydrocarbons over Y zeolites with varying Si/Al ratio

1987 ◽  
Vol 52 (7) ◽  
pp. 1701-1707 ◽  
Author(s):  
Miloslav Křivánek ◽  
Nguyen Thiet Dung ◽  
Pavel Jírů
Keyword(s):  
Catalytic Activity ◽  
Reaction Time ◽  
Coke Formation ◽  
Aliphatic Hydrocarbons ◽  
Y Zeolite ◽  
Y Zeolites ◽  
Methanol To Hydrocarbons

The catalytic activity of Na, H-Y zeolite samples with a varying Si/Al ratio (2·5 to 20) in the transformation of methanol was determined. The amounts of formed individual aliphatic hydrocarbons as function of reaction time were correlated with the amount of Bronsted and Lewis centres on the catalysts. The effect of coke formation on the over-all course of the reaction has been demonstrated.

Synthesis of Macro-Porous De-NOx Catalysts for Poly-Tetra-Fluoro-Ethylene Membrane Bag Filter

2021 ◽  
Vol 21 (8) ◽  
pp. 4537-4543
Author(s):  
Byung Chan Kwon ◽  
Dohyung Kang ◽  
Seung Woo Lee ◽  
No-Kuk Park ◽  
Jang Hun Lee ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Nitrogen Oxides ◽  
Porous Alumina ◽  
Combustion Process ◽  
Textural Properties ◽  
Filter Material ◽  
Facilitated Diffusion ◽  
Exhaust Gas ◽  
Bag Filter ◽  
Combustion Exhaust

This study examined the effects of the porosity of catalytic bag-filter materials for applications to the SNCR (selective noncatalytic reduction)-SCR (selective catalytic reduction) hybrid process for highly treating nitrogen Oxides (NOx) in the exhaust gas of a combustion process. A V2O5/TiO2 catalyst was dispersed in a PTFE (poly-tetra-fluoro-ethylene) used as the catalytic bag-filter material to remove particulate matter and nitrogen oxides contained in the combustion exhaust gas. Macroporous alumina was added into a V2O5/TiO2-dispersed PTFE to improve the catalytic activity of V2O5/TiO2 dispersed in the PTFE material. In this study, the textural properties and denitrification performances of the V2O5/TiO2-dispersed PTFE materials were examined according to the addition of macro-porous alumina. When the denitrification catalyst was solely dispersed in the PTFE material, the catalyst inside the PTFE backbone had low gas-solid contact efficiency owing to the low porosity of the PTFE materials, resulting in low denitrification efficiency. On the other hand, the catalytic activity of V2O5/TiO2 dispersed inside the macro-porous PTFE material was significantly enhanced by adding macro-porous alumina into the PTFE matrix. The enhanced textural properties of the macro-porous PTFE material where V2O5/TiO2 was uniformly dispersed proved the facilitated diffusion of combustion exhaust gas into the PTFE material.

The Effect of Ni Precursor Salts on Diatomite Supported Ni-Mg Catalysts in Methanation of CO2

2021 ◽  
Vol 1016 ◽  
pp. 1417-1422
Author(s):  
Chao Sun ◽  
Jugoslav Krstic ◽  
Vojkan Radonjic ◽  
Miroslav Stankovic ◽  
Patrick da Costa
Keyword(s):  
Catalytic Activity ◽  
Atmospheric Pressure ◽  
Textural Properties ◽  
Catalytic Performance ◽  
Nickel Salt ◽  
Nitrate Salt ◽  
Efficient Catalyst ◽  
Mild Conditions ◽  
The Difference ◽  
Supported Ni

This study is aimed to investigate the effect of Ni precursor salts on the properties (textural, phase-structural, reducibility, and basicity), and catalytic performance of diatomite supported Ni-Mg catalyst in methanation of CO2. The NiMg/D-X catalysts derived from various nickel salts (X = S-sulfamate, N-nitrate or A-acetate) were synthesized by the precipitation-deposition (PD) method. The catalysts were characterized by N2-physisorption, XRD, TPR-H2, and TPD-CO2 techniques. The different catalytic activity (conversion) and selectivity, observed in CO2 methanation carried out under relatively mild conditions (atmospheric pressure; temperatures: 250-450 °C) are related and explained by the difference in textural properties, metallic Ni-crystallite size, reducibility, and basicity of studied catalysts. The results showed that catalyst derived from Ni-nitrate salt (NiMg/D-N) is more suitable for the preparation of efficient catalyst for CO2 methanation than its counterparts derived from sulfamate (NiMg/D-S) or acetate (NiMg/D-A) nickel salt. The NiMg/D-N catalyst showed the highest specific surface area and total basicity, and the best catalytic performance with CO2 conversion of 63.3 % and CH4 selectivity of 80.9 % at 450 °C.

scholarly journals Cellulose nanocrystals (CNCs) as hard templates for preparing mesoporous zeolite Y assemblies with high catalytic activity

2020 ◽  
Vol 22 (15) ◽  
pp. 5115-5122 ◽  
Author(s):  
Samer Abdulridha ◽  
Jiuxing Jiang ◽  
Shaojun Xu ◽  
Zhaoxia Zhou ◽  
He Liang ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Cellulose Nanocrystals ◽  
Zeolite Y ◽  
Synthesis Method ◽  
High Catalytic Activity ◽  
Mesoporous Zeolite ◽  
Y Zeolite ◽  
Directed Synthesis

Faujasite (FAU) Y zeolite assemblies with high mesoporosity (Sext = 347 m2 g−1 and Vmeso = 0.52 cm3 g−1) were synthesised using sustainable and economic cellulose nanocrystals (CNCs) via a template-directed synthesis method.

scholarly journals Carbon-Supported Fe Catalysts forCO2Electroreduction to High-Added Value Products: A DEMS Study: Effect of the Functionalization of the Support

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
S. Pérez-Rodríguez ◽  
G. García ◽  
L. Calvillo ◽  
V. Celorrio ◽  
E. Pastor ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Ethylene Glycol ◽  
Surface Chemistry ◽  
Physicochemical Properties ◽  
Electrochemical Properties ◽  
Textural Properties ◽  
Carbon Support ◽  
Product Distribution ◽  
Added Value ◽  
Fe Catalysts

Vulcan XC-72R-supported Fe catalysts have been synthesised for the electroreduction of CO2to high-added value products. Catalysts were obtained by the polyol method, using ethylene glycol as solvent and reducing agent. Prior to the metal deposition, Vulcan was subjected to different oxidation treatments in order to modify its surface chemistry and study its influence on the physicochemical and electrochemical properties of the catalysts, as well as on the product distribution. The oxidation treatments of the supports modify their textural properties, but do not affect significantly the physicochemical properties of catalysts. However, DEMS studies showed that the carbon support degradation, the distribution of products, and the catalytic activity toward the CO2electroreduction reaction depend significantly on the surface chemistry of the carbon support.

scholarly journals Sulfonated Hydrothermal Carbons from Cellulose and Glucose as Catalysts for Glycerol Ketalization

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 804 ◽  
Author(s):  
Fernández ◽  
Fraile ◽  
García-Bordejé ◽  
Pires
Keyword(s):  
Catalytic Activity ◽  
Heterogeneous Catalysis ◽  
Flow Reactor ◽  
Chemical Properties ◽  
Textural Properties ◽  
Catalytic Synthesis ◽  
Physical Chemical ◽  
Treatment Conditions ◽  
First Results ◽  
Work Up

Solketal is one of the most used glycerol-derived solvents. Its production via heterogeneous catalysis is crucial for avoiding important product losses typically found in the aqueous work-up in homogeneous catalysis. In this work, we present a study of the catalytic synthesis of solketal using sulfonated hydrothermal carbons (SHTC). They were prepared from glucose and cellulose resulting in different textural properties depending on the hydrothermal treatment conditions. The sulfonated hydrothermal carbons were also coated on a graphite microfiber felt (SHTC@GF). Thus, up to nine different solids were tested, and their activity was compared with commercial acidic resins. The solids presented very different catalytic activity, which did not correlate with their physical-chemical properties indicating that other aspects likely influence the transport of reactants and products to the catalytic surface. Additionally, the SHTC prepared from cellulose showed better reusability in batch reaction tests. This work also presents the first results for the production of solketal in a flow reactor, which opens the way to the use of SHTC@GF for this kind of reactions.

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