Topic
ZSM-5
About: ZSM-5 is a research topic. Over the lifetime, 3564 publications have been published within this topic receiving 107183 citations.
Papers published on a yearly basis
Papers
More filters
TL;DR: It is shown that appropriately designed bifunctional surfactants can direct the formation of zeolite structures on the mesoporous and microporous length scales simultaneously and thus yield MFI (ZSM-5, one of the most important catalysts in the petrochemical industry) zeolites that are only 2 nm thick, which corresponds to the b-axis dimension of a single MFI unit cell.
Abstract: Zeolites-microporous crystalline aluminosilicates-are widely used in petrochemistry and fine-chemical synthesis because strong acid sites within their uniform micropores enable size- and shape-selective catalysis. But the very presence of the micropores, with aperture diameters below 1 nm, often goes hand-in-hand with diffusion limitations that adversely affect catalytic activity. The problem can be overcome by reducing the thickness of the zeolite crystals, which reduces diffusion path lengths and thus improves molecular diffusion. This has been realized by synthesizing zeolite nanocrystals, by exfoliating layered zeolites, and by introducing mesopores in the microporous material through templating strategies or demetallation processes. But except for the exfoliation, none of these strategies has produced 'ultrathin' zeolites with thicknesses below 5 nm. Here we show that appropriately designed bifunctional surfactants can direct the formation of zeolite structures on the mesoporous and microporous length scales simultaneously and thus yield MFI (ZSM-5, one of the most important catalysts in the petrochemical industry) zeolite nanosheets that are only 2 nm thick, which corresponds to the b-axis dimension of a single MFI unit cell. The large number of acid sites on the external surface of these zeolites renders them highly active for the catalytic conversion of large organic molecules, and the reduced crystal thickness facilitates diffusion and thereby dramatically suppresses catalyst deactivation through coke deposition during methanol-to-gasoline conversion. We expect that our synthesis approach could be applied to other zeolites to improve their performance in a range of important catalytic applications.
1,839 citations
Patent•
10 Oct 1969TL;DR: A family of crystal spheres called ZSM-5 is described in this paper, with the following characteristics: 0.9$0.2M2/NO:W2O3:5-100YO2:ZH2O wherein M is at least one locality, N is the valence threshold, W is selected from the group consisting of ALUMINUM and GALLIUM, Y is chosen from the grouping consisting of SILICON and GERMANIUM, and Z is from 0-40, and CHARACTERIZED by a SPEC
Abstract: A FAMILY OF CRYSTALLINE ZEOLITES, DESIGNATED ZSM-5, HAVING THE COMPOSITION, EXPRESSED AS MOLE RATIOS OF OXIDES AS FOLLOWS: 0.9$0.2M2/NO:W2O3:5-100YO2:ZH2O WHEREIN M IS AT LEAST ONE CATION, N IS THE VALENCE THEREOF, W IS SELECTED FROM THE GROUP CONSISTING OF ALUMINUM AND GALLIUM, Y IS SELECTED FROM THE GROUP CONSISTING OF SILICON AND GERMANIUM, AND Z IS FROM 0-40, AND CHARACTERIZED BY A SPECIFIED X-RAY POWDER DIFFRACTION PATTERN. CATALYTIC CONVERSION CARRIED OUT IN THE PRESENCE OF SUCH ZEOLITES.
1,134 citations
TL;DR: In this article, the shape selective catalysts with unique channel structures have been determined using model building, single crystal and powder X-ray data, and they have been shown to possess unusual catalytic properties and high thermal stability.
Abstract: ZEOLITE ZSM-5 (ref. 1) is a member of a new class of shape selective catalysts with unique channel structures which differ from the familiar large-pore faujasite and small-pore zeolites such as Linde Type A and erionite. They also possess unusual catalytic properties and have high thermal stability. We have determined their structure using model building, single crystal and powder X-ray data.
870 citations
TL;DR: In this article, the reaction mechanism with respect to both catalyst deactivation and product formation in the conversion of methanol to hydrocarbons over zeolite H-ZSM-5 was examined.
848 citations
TL;DR: In this paper, the influence of various employed promoters on the chemical properties of the modified ZSM-5 and the performance of resulting catalyst in enhancing the selectivity to light olefins, have been addressed.
Abstract: Steam cracking of hydrocarbons has been the major source of light olefins for more than half a century. The recent studies have reported that ethylene and propylene can also be produced through the cracking of hydrocarbons over modified ZSM-5 zeolites in a considerable amount. This paper highlights the important current ideas about acid-catalyzed hydrocarbon cracking that has resulted in high yield of ethylene and propylene. Light olefin production via catalytic cracking of various industrial feedstocks, ranging from heavy hydrocarbons to ethane, over modified ZSM-5 zeolites, has been reviewed in the present paper. Furthermore, the influence of various employed promoters, i.e., alkali and alkaline earth, transition, rare earth elements, and phosphorus, on the chemical properties of the modified ZSM-5 and the performance of resulting catalyst in enhancing the selectivity to light olefins, have been addressed. Moreover, the influences of different factors, including the zeolite acidity, Si/Al ratio and the temperature, on the light olefin production and the reaction scheme have been specified. The role of incorporated element in the catalytic cracking mechanism is also summarized.
657 citations