نتایج جستجو برای: hierarchical ZSM-5 zeolite
تعداد نتایج: 1308277 فیلتر نتایج به سال:
Hierarchical ZSM-5 zeolite is hydrothermally synthesized in a single step with cetyltrimethylammonium (CTA) hydroxide acting as mesoporogen and structure-directing agent. Essential to this synthesis is the replacement of NaOH with KOH. An in-depth solid-state NMR study reveals that, after early electrostatic interaction between condensed silica and the head group of CTA, ZSM-5 crystallizes arou...
ZSM-5 zeolite is widely used in catalytic cracking of hydrocarbon, but the conventional ZSM-5 zeolite deactivates quickly due to its simple microporous and long diffusion pathway. Many studies have been done to overcome these disadvantages recently. In this review, four main approaches for enhancing the catalytic performance, namely synthesis of ZSM-5 zeolite with special morphology, hierarchic...
Phenol is an important industrial intermediate for the production of various chemicals such as bisphenol A, phenolic resins, caprolactam, alkylphenols and adipic acid. The cumene hydroperoxide process is the currently used industrial method to produce phenol. Its environmentally stressing aspects have spurred research to replace this process with more benign approaches such as the direct oxidat...
A new kind of organosilane (1,6-bis (diethyl(3-trimethoxysilylpropyl)ammonium) hexane bromide) with a geminitype structure was prepared and used as a mesoporogen for the synthesis of hierarchical porous ZSM-5 zeolite. There are two quaternary ammonium centers along with double hydrolysable -RSi(OMe)3 fragments in the organosilane, which results in a strong interaction between this mesoporogen a...
Zeolite fibers have attracted growing interest for a range of new applications because of their structural particularity while maintaining the intrinsic performances of the building blocks of zeolites. The fabrication of uniform zeolite fibers with tunable hierarchical porosity and further exploration of their catalytic potential are of great importance. Here, we present a versatile and facile ...
We report the one-step synthesis of a highly active hierarchical Fe/ZSM-5 zeolite catalyst with a strongly improved lifetime in the selective hydroxylation of benzene to phenol with nitrous oxide; compared to the best Fe/ZSM-5 catalyst, the turnover number after 24 h on stream is almost four times higher.
This study examines the performance of a new adsorbent, hexagonal nanostructured zeolite particles (HNZP) for acetone adsorption and compares the results with that of commercial mobil synthetic zeolite-5 (ZSM-5) type zeolite. The HNZP is a pure siliceous adsorbent with different values of pore diameter and surface area being adjustable by the manufacturing condition. The results indicate that a...
Hierarchical zeolite monoliths with multimodal porosity are of paramount importance as they open up new horizons for advanced applications. So far, hierarchical zeolites based on nanotube scaffolds have never been reported. Inspired by the organization of biominerals, we have developed a novel precursor scaffolding-solid phase crystallization strategy for hierarchical zeolites with a unique nan...
The present work introduces the study of the CO2 capture process by zeolites synthesized from paper sludge and scrap glass. Zeolites ZSM-5, analcime and wairakite were produced by means of two types of Structure Directing Agents (SDA): tetrapropilamonium (TPA) and ethanol. On the one hand, zeolite ZSM-5 was synthesized using TPA; on the other hand, analcime and wairakite were produced with etha...
The relatively small and sole micropores in zeolite catalysts strongly influence the mass transfer and catalytic conversion of bulky molecules. We report here aluminosilicate zeolite ZSM-5 single crystals with b-axis-aligned mesopores, synthesized using a designed cationicamphiphilic copolymer as a mesoscale template. This sample exhibits excellent hydrothermal stability. The orientation of the...
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