نتایج جستجو برای: hierarchical zsm 5 zeolite
تعداد نتایج: 1308277 فیلتر نتایج به سال:
As stock of crude oil is limited, new resources for fuel and petrochemicals are required to be developed. Natural gas or biogas can be easily converted into methanol which can be converted into gasoline and olefins. This study uses zeolite catalyst (ZSM-5) and its modification by Ni to convert methanol to hydrocarbons (MTH). Catalysts are studied at different temperatures and at different loadi...
zeolite zsm-5 presents a great source of interest in catalysis because of its shape selective properties. the absence of a relationship between the template size and shape of the structure generated during the synthesis of zeolites is illustrated by the case of zsm-5. in this study, we have investigated the role of ethanol, methyltriphenylphosphonium bromide (mtpbr) and cetyltrimethylammonium b...
Title of Document: SYNTHESIS OF ZEOLITE@MOF NANOPOROUS COMPOSITES AS BIFUNCTIONAL CATALYSTS Guanghui Zhu, Master of Science, 2014 Directed By: Professor, Dr. Dongxia Liu, Department of Chemical and Biomolecular Engineering And Professor, Dr. Kyu Yong Choi, Department of Chemical and Biomolecular Engineering As nanoporous materials, zeolite and metal organic framework (MOF) share common characte...
Large-scale density functional theory calculations (DFT) found various types of binding of an unsaturated hydrocarbon (C2H2 and C2H4) to a ZSM-5 zeolite extraframework copper cation. We employed the DFT calculations based on the B3LYP functional to obtain local minima of an unsaturated hydrocarbon adsorbed on one or two copper cations embedded inside ZSM-5, and then compared their stabilization...
Interpretation of catalytic performance during the MTH process is hampered by heat transport phenomena. We demonstrate that large temperature rises can occur during fixed bed labscale catalyst testing of ZSM-5, even when a large catalyst bed dilution is applied. Formation of mesopores in ZSM-5 leads to partial mitigation of these effects because of a lower generation of heat per unit catalyst v...
Perfluoroalkylglucosides comprise a very important class of fluorine-containing surfactants. These compounds can be synthesized by using the Fisher reaction, starting directly from glucose and the required perfluoroalcohols. We wish to report on the use of zeolite catalysts of different structure and composition for the synthesis of perfluoroalkylglucosides when using glucose and 1-octafluorope...
An Investigation of the Behavior of Completely Siliceous Zeolite ZSM-5 under High External Pressures
Zeolites are microporous aluminosilicates with well-defined channels and cavities. They have been widely used as ionexchangers, molecular sieves, sorbents, and catalysts. The stability of zeolites is crucial to their applications. Many experimental and theoretical studies have been concentrated on their thermal stability. On the contrary, their behavior under external high pressures has receive...
Adsorption of carbonmonoxide on the silver ion-exchanged Ag-ZSM-5 zeolite has been studied using both quantum cluster and embedded cluster at the models B3LYP/6-31G(d,p) level of theory. The Ag...Oz distance in Ag-ZSM-5 complexes is predicted to be 2.26 Å for the quantum cluster and 2.32 Å for the embedded cluster, the latter is in agreement with the experimental value of 2.30 + 0.03 Å. The opt...
Aluminum coordination in the framework of USY and ZSM-5 zeolites containing charge-compensating cations (NH4+, H+, or Cu+) was investigated by Al K-edge EXAFS and XANES. This work was performed using a newly developed in-situ cell designed especially for acquiring soft X-ray absorption data. Both tetrahedrally and octahedrally coordinated Al were observed for hydrated H-USY and H-ZSM-5, in good...
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