Palladium–Silver Sol-Gel Catalysts for Selective Hydrodechlorination of 1,2-Dichloroethane into Ethylene

Heinrichs, Benoı̂t; Delhez, Patrice; Schoebrechts, Jean‐Paul; Pirard, Jean-Paul

doi:10.1006/jcat.1997.1881

Cited by 133 publications

(101 citation statements)

References 39 publications

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“…It is known that upgrading HdCl catalytic performance would be achieved by doping palladium with another, usually less active, metal, like silver [10][11][12][13][14], copper [15] and gold [16]. In this respect our recent report on HdCl of CCl 4 on carbon-supported Pd-Au clearly shows that good intermixing of the both metals is crucial for getting a superior catalytic performance [16].…”

Section: Introductionmentioning

confidence: 92%

Effect of silver on the catalytic hydrodechlorination of tetrachloromethane over silica-supported palladium-silver catalysts

Bonarowska

Kaszkur

Karpiński

2015

Recyclable Catalysis

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Two silica-supported palladium based catalysts characterized by overall metal loadings 10 wt.%, and atomic Pd : Ag ratios of 100 : 0 and 70 : 30, were prepared by incipient wetness impregnation, subjected to reduction in hydrogen and characterized by XRD. It was found that incipient wetness co-impregnation of silica resulted in the formation of a catalyst characterized by relatively small metal crystallites (~11 nm) and significant extent of Pd-Ag alloying. The catalytic performance was investigated in the hydrodechlorination of tetrachloromethane in the gas phase. Silver addition to palladium in the co-impregnated catalysts had very pronounced effect, vastly decreasing the overall activity (conversion) and also the selectivity towards hydrocarbons, propensity characteristic for the monometallic palladium catalysts working in CCl4 hydrodechlorination carried out in the gas phase. Instead, large amounts of C2HxCly dimeric products were formed. These dimers are considered as possible coke precursors. Post-reaction samples of both catalysts contained large amount of carbon which entered the Pd and Pd-Ag phases. This carbon can be easily removed by treatment with hydrogen at 450ºC.

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Section: Introductionmentioning

confidence: 92%

Effect of silver on the catalytic hydrodechlorination of tetrachloromethane over silica-supported palladium-silver catalysts

Bonarowska

Kaszkur

Karpiński

2015

Recyclable Catalysis

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“…To a suspension containing 0.121 g of insoluble palladium acetylacetonate powder (Pd(acac) 2 , Aldrich 20, 901-5) and 0.131 g of insoluble silver acetate powder (AgOAc, Aldrich 20, 437-4) in 13.03 ml of ethanol denaturized with 0.5% of diethyl phthalate (DEP), 0.51 ml of [3-(2-aminoethyl)aminopropyl]trimethoxysilane (EDAS, ABCR 1760-24-3, industrial grade) is added. This mixture is stirred at ambient temperature in a closed vessel during 1 h to allow EDAS to form complexes with Pd and Ag [1]. Tetraethoxysilane, 9.44ml, (TEOS, ABCR 78-10-4, industrial grade) is then added.…”

Section: Initial Sol-gel Solutionmentioning

confidence: 99%

“…Previously, the synthesis by cogelation, the characterization and the catalytic properties of Pd-Ag/SiO2 xerogel catalysts have been reported [1,2]. This cogelled catalyst is devoted to the selective hydrodechlorination of chlorinated alkanes into alkenes.…”

Section: Introductionmentioning

confidence: 99%

Image analysis of X-ray microtomograms of Pd–Ag/SiO2 xerogel catalysts supported on Al2O3 foams

Blacher

Léonard

Heinrichs

et al. 2004

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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In order to preshape and mechanically strengthen, Pd-Ag/SiO 2 xerogel catalysts were carried out in A1 2 0 3 foams (pore-sizes ~40 µm). The final material consists of a Pd-Ag/SiO 2 xerogel immobilized in the open cells of the alumina foam. The localization of the xerogel catalyst in alumina foams of various pore structure was studied by X-ray microtomography. The three-dimensional (3D) porous structure was reconstructed from the consecutive cross-sections obtained by this technique. Total porosity, porous density distribution, and pore-size distribution were determined by image analysis on the free and impregnated supports. Our results show that the success of the used impregnation technique depends on the pore structure of the support.

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“…This synthesis method consists in co-gelation of tetraethylorthosilicate TEOS with additives with functional groups of the form (RO) 3 Si-X-A, in which A is a functional organic group able to form a chelate with a metal cation and X is an inert hydrolytically stable spacer, which links A to the hydrolysable group (RO) 3 Si-. These additives enable to introduce the metal directly during the synthesis of the catalytic support rather than dispersing the active component on a previously synthesised support [7][8][9][10][11][12][13][14]. The co-condensation of TEOS with such molecules results in materials in which the catalytic metal is anchored to the SiO 2 matrix.…”

Section: Introductionmentioning

confidence: 99%

“…3-(2-Aminoethylamino)propyltrimethoxysilane (EDAS) is one of these interesting additives that can be employed to homogeneously disperse nanometer-sized metal particles in a silica matrix. The catalyst composition chosen for immobilization inside the alumina foam is the metal loading that gives the highest selectivity for hydrodechlorination of 1,2-dichloroethane into ethylene [12], i.e., 1.5wt.% Pd and 3 wt.% Ag. The alumina foams are immersed in the sol-gel solution containing Pd, Ag, the SiO 2 precursors EDAS and TEOS, water and ethanol before gelation.…”

Section: Introductionmentioning

confidence: 99%

Pd–Ag/SiO2 xerogel catalyst forming by impregnation on alumina foams

Alié

Ferauche

Léonard

et al. 2006

Chemical Engineering Journal

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A Pd-Ag/SiO 2 xerogel catalyst prepared in one step by sol-gel process has been entrapped in cylindrical porous alumina foams of three different pore sizes in order to shape the catalyst under the appropriate form with suitable mechanical resistance to be used in an industrial fixed bed reactor. After drying, calcination and reduction, the Pd-Ag/SiO 2 xerogel catalyst pellets are immobilized inside the open porosity of the alumina foam. The localization of the xerogel catalyst in the alumina foams has been studied by X-ray tomography. The threedimensional porous structure was reconstructed from the consecutive cross-sections obtained by this technique. This method shows that the Pd-Ag/SiO 2 xerogel catalyst is uniformly dispersed inside the porosity of the alumina foams. Activity and selectivity of Pd-Ag/SiO 2 xerogel catalyst reference or catalyst entrapped in alumina foams have been studied for selective hydrodechlorination of 1,2-dichloroethane into ethylene. The specific reaction rate obtained with catalyst entrapped in alumina foams is smaller than the one obtained from corresponding catalyst powders. The catalytic activity decrease observed for Pd-Ag/SiO 2 xerogel catalyst entrapped in porous alumina foams most probably arises from diffusional limitations inside the porous texture of the alumina foams.

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Palladium–Silver Sol-Gel Catalysts for Selective Hydrodechlorination of 1,2-Dichloroethane into Ethylene

Cited by 133 publications

References 39 publications

Effect of silver on the catalytic hydrodechlorination of tetrachloromethane over silica-supported palladium-silver catalysts

Effect of silver on the catalytic hydrodechlorination of tetrachloromethane over silica-supported palladium-silver catalysts

Image analysis of X-ray microtomograms of Pd–Ag/SiO2 xerogel catalysts supported on Al2O3 foams

Pd–Ag/SiO2 xerogel catalyst forming by impregnation on alumina foams

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