A new way to Ti-containing zeolite beta catalysts for selective oxidation

Renzo, Francesco Di; Gomez, Sylvie; Teissier, Rémi; Fajula, François

doi:10.1016/s0167-2991(00)80434-6

Cited by 9 publications

(2 citation statements)

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“…In this work, we investigate the crystallization process of aluminum-free zeolite-Beta functionalized by titanium. Titanium-modified zeolite-Beta shows remarkable catalytic activity for the selective epoxidation of several alkanes − and for the cracking of polyolefins . It also exhibits photocatalytic activity for the reduction of carbon dioxide .…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic Investigation of Ti-Modified Aluminum-Free Zeolite-Beta Crystallization

et al. 2011

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Crystallization of aluminum-free zeolite-Beta from viscous gel and incorporation of titanium into its framework were investigated by several spectroscopic techniques. Hydrothermal synthesis was stopped at different times and the gels obtained from the autoclaves were analyzed by liquid-state 29 Si NMR spectroscopy. The gels were subsequently dried and inspected by solid-state 29 Si NMR, Fourier-transform infrared, and X-ray absorption spectroscopy. NMR spectroscopy distinguished signals from oligomers and from two populations of nanoparticles with different typical dimensions. It also provided information about the composition of the oligomers and nanoparticles, in terms of the relative fractions of Q n units within them. Investigation showed that the synthesis of zeolite Ti-Beta started with a quick formation of oligomers. After 20 h of the hydrothermal treatment, oligomers with a high fraction of Q 3 units gradually aggregated into primary nanoparticles with a diameter of ∼2 nm. During first 20 h, primary nanoparticles began to agglomerate into secondary nanoparticles with a diameter of 5-10 nm. These nanoparticles already had a high fraction of Q 4 units and already possessed a zeolitic character. With a further increase in the hydrothermal treatment time, the concentration of secondary nanoparticles increased and they started to gather into zeolitic crystallites. Ti atoms were incorporated into the growing silicate framework at a very early stage of the crystallization process.

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Section: Introductionmentioning

confidence: 99%

Spectroscopic Investigation of Ti-Modified Aluminum-Free Zeolite-Beta Crystallization

et al. 2011

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“…Ti-ZSM-48 [16], TAPSO-5 [20], Ti-ITQ-7 [23,24] were also synthesized and used as oxidation catalysts. The method for the postsynthesis incorporation of Ti into the zeolite beta was also applied to the incorporation of Ti into MOR and FAU [62]. The method for the postsynthesis incorporation of Ti into the zeolite beta was also applied to the incorporation of Ti into MOR and FAU [62].…”

Section: Other Titanium-containing Zeolitesmentioning

confidence: 99%

Metals in Zeolites for Oxidation Catalysis

Tatsumi

2010

Zeolites and Catalysis

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Zeolites have long been used as solid acid catalysts. The fluid catalytic cracking of heavy fractions of petroleum by the use of Y-type zeolites included in catalyst matrices is the world's largest catalytic process. Acidic zeolites have also widely replaced mineral and Lewis acids in large-scale chemical manufacturing such as alkylation of aromatics and the Beckmann rearrangement. Zeolites are also endowed with the redox property by the incorporation of a variety of metals, and this chapter deals with incorporation of metals and the resultant oxidation catalysis.The ways to introduce heteroatoms into zeolites are classified into two categories: heteroatoms can be introduced into the framework as well as into voids as extraframework species. Most zeolites have an intrinsic ability to exchange cations [1]. This ability to exchange is a result of isomorphous substitution of a cation of trivalent (mostly Al) or lower charges for Si as a tetravalent framework cation. As a consequence of this substitution, a net negative charge develops on the framework of the zeolite, which has to be neutralized by cations present within the channels or cages that constitute the microporous part of the crystalline zeolite. These cations may be any of the metals, metal complexes, or alkylammonium cations. If these cations are transition metals with redox properties, they can act as active sites for oxidation reactions. As a pioneering work, Wacker-type reactions were catalyzed by Y zeolite into which Pd 2+ and Cu 2+ were incorporated by ion exchange [2].Research on coordination chemistry in zeolites started in 1970s and early work was summarized by Lunsford [3]. A metal complex of the appropriate dimensions can be encapsulated in a zeolite, being viewed as a bridge between homogeneous and heterogeneous systems. Complexes that are smaller than the free diameters of the channels and windows have access to the cavities. On the other hand, complexes that are larger than the diameters of the windows must be synthesized in situ, namely, by the adsorption of the ligands into the zeolites containing transition metal ions or by the synthesis of the ligands in those zeolites [4][5][6]. Herron et al. first referred to such zeolite guest molecules as ship-in-a-bottle complexes [7]. Cationic complexes can be tethered to zeolites through the electrostatic interaction. However,

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Oxidation Reactions Catalyzed by Transition‐Metal‐Substituted Zeolites

Clerici¹,

Dómine²

2013

Liquid Phase Oxidation via Heterogeneous Catalysis

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A new way to Ti-containing zeolite beta catalysts for selective oxidation

Cited by 9 publications

References 10 publications

Spectroscopic Investigation of Ti-Modified Aluminum-Free Zeolite-Beta Crystallization

Spectroscopic Investigation of Ti-Modified Aluminum-Free Zeolite-Beta Crystallization

Metals in Zeolites for Oxidation Catalysis

Oxidation Reactions Catalyzed by Transition‐Metal‐Substituted Zeolites

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