Zeolite Effects in Organic Catalysis

Espeel, Patrick; Parton, Rudy F.; Toufar, Helge; Martens, Johan A.; Hölderich, Wolfgang F.; Jacobs, Pierre

doi:10.1007/978-3-662-03764-5_6

Cited by 15 publications

(11 citation statements)

References 242 publications

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“…There are excellent, almost exhaustive overviews of organic reactions catalyzed by zeolites (1)(2)(3)(4). Instead of pursuing completeness, this chapter intends to illustrate zeolite effects on fine chemicals transformations with a series of wellselected and recent examples.…”

Section: Introductionmentioning

confidence: 98%

Zeolite Effects on Catalytic Transformations of Fine Chemicals

Vos

Jacobs

2002

Zeolites for Cleaner Technologies

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Section: Introductionmentioning

confidence: 98%

Zeolite Effects on Catalytic Transformations of Fine Chemicals

Vos

Jacobs

2002

Zeolites for Cleaner Technologies

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“…The advantages of zeolites over other solids are, according to Espeel et al, 4 their great acid strength and practically unlimited applicability to different types of catalysis. The main weaknesses are that they are very sensitive to deactivation by irreversible adsorption or pore blockage by heavy products, and also the incompatibility in size of molecules resulting from the fine chemicals area and the cages of the micropores.…”

mentioning

confidence: 99%

“…The main weaknesses are that they are very sensitive to deactivation by irreversible adsorption or pore blockage by heavy products, and also the incompatibility in size of molecules resulting from the fine chemicals area and the cages of the micropores. 4 Metals supported on zeolites are prepared by incorporating the transition metal either by cation exchange or an impregnation procedure and then reducing the transition metal. The design of the supported catalyst is based mainly on the knowledge of the interaction and location of the active phase on the support.…”

mentioning

confidence: 99%

Preparation of rhodium catalysts on laminar and zeolitic structures by anchoring of organometallic rhodium

Blanco

Ruiz

Pesquera

et al. 2001

Applied Organom Chemis

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Rhodium catalysts supported on six different aluminosilicate structures were prepared by hydrogen reduction of a cationic organometallic rhodium complex anchored to the support. The precursor active phase was incorporated in acetone medium through ion exchange using [Rh(Me 2 CO) x (NBD)]-ClO 4 as the metal precursor species, in which NBD is 2,5-norbornadiene and (Me 2 CO) x is acetone. The effect of the structure and characteristics of the support on metal load and dispersion was studied in the heterogeneous catalysts thus prepared. The supports were characterized by X-ray diffraction, energy-dispersive X-ray analysis, volumetric adsorption and surface acidity. For the precursors and catalysts, the metal load was determined by UV±VIS spectra, the reduction temperature was determined by differential scanning calorimetry, and rhodium dispersion was measured by chemisorption. The structure of the materials used as supports had a great influence on the catalyst prepared. A higher metal content was achieved in the supports with laminar structures, whereas better dispersion was shown by the catalysts supported on zeolitic structures. Copyright # 2001 John Wiley & Sons, Ltd.KEYWORDS: organometallic rhodium; montmorillonite; zeolitic products; catalyst preparation Zeolites and zeolitic materials have an increasing role in heterogeneous catalysis, and are widely applied in largescale industrial processes. Developments in the synthesis and characterization of zeolites have favored the design of materials that efficiently accelerate the reaction and which, therefore, help to achieve favorable thermodynamics and rates, as well as controlling the selectivity of a chemical reaction.1 Activity, selectivity and durability are characteristics that favor the use of heterogeneous catalysts in a wide range of chemical reactions under different pressure and temperature conditions. In view of their characteristics, natural and synthetic aluminosilicates have been used as catalysts and heterogeneous catalysts for a great number of active phases. In addition, clays and zeolites have advantages as supports because they are chemically and physically robust, and inexpensive. Clays can easily be modified to improve their catalytic properties. For instance, in smectites, interlayer spacing can be adjusted by introducing substituents, by pillaring or solvent swelling, or even by transformation to new structures, and the acidic nature of the structure can also usefully be altered to improve their selectivity. 3 In any aluminosilicate, the porous structure provides a high surface area that enables it to receive high charges of a welldispersed active component. Therefore, the industrial efficacy of aluminosilicates results from a combination of porosity and mechanical resistance. Zeolites and zeolite-like products have regular pore and cage dimensions, which makes them different from other aluminosilicates. Most of the active sites are located in the molecular size pores and cages so that, during the reaction, the transforming molecules are subj...

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“…[2] Among them, heterogeneously catalysed Friedel±Crafts alkylation reactions are receiving a great deal of attention even for large scale processes. [3] Catalytic and stereoselective alkylation of indoles via 1,4-addition to electron-deficient double bonds is an important organic reaction that affords products that may be transformed into valuable building blocks.…”

mentioning

confidence: 99%

“…Firstly, by selecting the batch 1,4-addition of 2-methylindole (1) to 2-cyclohexen-1-one (2) as the model reaction, a range of solid acids were screened as catalysts (Scheme 1). [6] From the data collected in Table 1 it emerges that, although in the absence of promoting agent the reaction did not occur in significant extents over 24 h reaction time, commercial ion-exchange sulfonic resins such as Amberlyst-15, 35, 36 and 40, employed at 20% wt, allowed 3 to be isolated in high yields (61 ± 76%).…”

mentioning

confidence: 99%

Solid Acid‐Catalysed Michael‐Type Conjugate Addition of Indoles to Electron‐Poor CC Bonds: Towards High Atom Economical Semicontinuous Processes

2004

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In this paper a novel application of solid acid catalysts in the chemoselective Friedel±Crafts (FC) alkylation of indoles is reported. The optimal protocol allows highly functionalised indolyl compounds to be synthesised in excellent yields through conjugate addition of indoles with a,b-unsaturated ketones and nitro compounds. Finally, the use of commercial Amberlyst-15 as the heterogeneous catalyst for highly atom efficient continuous and semicontinuous Friedel±Crafts processes is described.

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Zeolite Effects in Organic Catalysis

Cited by 15 publications

References 242 publications

Zeolite Effects on Catalytic Transformations of Fine Chemicals

Zeolite Effects on Catalytic Transformations of Fine Chemicals

Preparation of rhodium catalysts on laminar and zeolitic structures by anchoring of organometallic rhodium

Solid Acid‐Catalysed Michael‐Type Conjugate Addition of Indoles to Electron‐Poor CC Bonds: Towards High Atom Economical Semicontinuous Processes

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