Supported palladium–copper catalysts: Preparation and catalytic behavior in hydrogen-related reactions

Bonarowska, Magdalena; Machynskyy, Ostap; Łomot, Dariusz; Kemnitz, Erhard; Karpiński, Zbigniew

doi:10.1016/j.cattod.2014.01.029

Cited by 17 publications

(7 citation statements)

References 38 publications

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“…The authors of [74,[81][82][83] showed that the addition of Cu to Pd-, Pt-, Ni-containing catalysts results in the predominant formation of unsaturated hydrocarbons during the chloralkanes hydrodechlorination. The reason for this, according to [9,84], is the enrichment of the catalyst surface with copper while reducing the copper content on the surface during adsorption of chloralkanes (1,2-dichloroethane, 1,1,2-trichloroethane).…”

Section: Catalytic Systemsmentioning

confidence: 99%

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Flid¹,

Kartashov²,

Treger³

2020

Catalysts

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The commercial implementation of hydrodechlorination processes will be an essential step in resolving the problem of environmentally sound organochlorine wastes processing. By now, there is a number of fundamental, applied, and process elaborations of such processes, in which chlorine is almost completely removed from wastes. The review article contains a significant number of results including basic regularities of thermal hydrodechlorination, comprehensive and selective catalytic hydrodechlorination. It discusses thermodynamics, kinetics, and catalysts of gas and liquid phase processes. Considerable attention is paid to hydrodechlorination of vinyl chloride production wastes and utilization of tetrachloromethane, which is the ozone-depleting substance. It also discusses hydrodechlorination of mono-and (poly)chlorobenzenes. The important examples of liquid phase data include hydrogenation using complex hydrides of elements. It also includes several flow sheets of hydrodechlorination processes.Various methods for C-Cl bonds reduction in non-cyclic organochlorine compounds can be divided into the following groups:Catalysts 2020, 10, 216 3 of 52 one should note the reviews [4,10] published in the 1990s. It is noted that catalytic methods are more widely used for hydrodechlorination. Electrochemical ReductionElectrochemical reduction is a complex process in which the speed and direction of reactions depend on many factors. It is characterized by the following features. Two electrons are spent for breaking the C-Cl bond; the half-wave potential in most cases does not depend on the pH of the medium; in general, the electrode reaction is irreversible [1]. There is an approximate linear relationship between the half-wave potential of the reactionsIn [12], a scheme was proposed describing the mechanism of electrochemical reduction of the C-Cl bondRClHowever, there is another point of view, according to which there is a simultaneous transfer of a pair of electrons, similar to that for nucleophilic substitution reactions [1].Electrochemical reduction is carried out on cathodes of copper, zinc, amalgamated zinc, palladium, cadmium, mercury, and lead [13]. The cathodic dechlorination proceeds in an alkaline environment more efficiently than in an acidic one; however, in most cases, acidic electrolytes are used to avoid such side reactions as saponification [13,14]. The recovery is usually carried out in inert solvents, in particular in alcohols. In [13], the influence of the reduction conditions-the cathode material, current density, the nature of electrolyte and solvent, the concentration of the reducible substance, and temperature-on the course of the reaction is described.The recovery of monochlorohydrocarbons is difficult and results mainly in the replacement of chlorine by hydrogen in accordance with the overall equationIn some cases, dimeric compounds (R-R) are formed according to the schemeThe recovery of vinyl chlorine is difficult, and that of the allyl one is facilitated in comparison with chlorine in saturated com...

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Section: Catalytic Systemsmentioning

confidence: 99%

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Flid¹,

Kartashov²,

Treger³

2020

Catalysts

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“…Bonarowska showed the effect of copper addition to supported palladium on the catalytic performance on hydroisomerization of n‐pentane. Again, Pd−Cu alloy formation was seen as the main reason for the improved selectivity [15] …”

Section: Resultsmentioning

confidence: 96%

“…Again, PdÀ Cu alloy formation was seen as the main reason for the improved selectivity. [15] Encouraged by these results, several different bimetallic palladium/copper catalysts on activated carbon were prepared on purpose using the precipitation method starting from a pre-Table 1. Hydrogenation of 2-chlorobenzaldehyde under different conditions.…”

Section: Resultsmentioning

confidence: 99%

Heterogeneous Catalyzed Chemoselective Reductive Amination of Halogenated Aromatic Aldehydes

et al. 2021

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The chemoselective conversion of a specific functional group in a multifunctional substrate is of great importance in the chemical industry to obtain cost efficient, sustainable and waste free processes. This work focuses on the chemoselective amination of halogenated aromatic aldehydes with dimethyl amine towards halogenated aromatic amines, a raw material used in the production of for example agrochemical active ingredients. It was found that by combining palladium, a metal known for dehalogenation reactions, and copper, known for its direct hydrogenation of aldehydes to alcohols, in one heterogeneous bimetallic catalyst, a synergistic effect is obtained. By depositing copper onto a palladium on carbon catalyst with a Cu/Pd ratio of at least 1 : 1, the yield could be increased from 66 % (Pd/C) to 98 % (PdCu/C). Moreover, this highly active and stable catalyst also showed suppressed dehalogenation sidereactions in several other chemical conversions such as hydrogenation of nitro functional groups and hydrogenation of aldehydes.

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“…In the past decade, metal fluorides, such as MgF 2 and AlF 3 , with significant surface areas were successfully used in different heterogeneous catalytic processes with promising results as catalysts [18][19][20][21][22][23] and supports [24][25][26][27]. Specifically, in 2003, Kemnitz and co-workers have developed a sol-gel synthesis leading to the formation of amorphous aluminum fluoride with very high specific surface area and very high Lewis acidity [28].…”

Section: Introductionmentioning

confidence: 99%

Inorganic hydroxide fluorides as solid catalysts for acylation of 2-methylfuran by acetic anhydride

Frouri

Célérier

Ayrault

et al. 2015

Applied Catalysis B: Environmental

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Several inorganic hydroxide fluorides MF n-x (OH) x with M being either aluminum, iron or magnesium were synthetized using a sol-gel method. These mesoporous fluoride materials exhibited very high specific surface areas (between 60 and 370 m 2 g -1 ) depending on the synthesis parameters used (nature of the metal, HF/Al ratio and thermal treatment). It is shown that their acidic properties can also be adjusted by tuning these parameters. Indeed, in the case of aluminum hydroxide fluorides, bi-acidic catalysts containing both Brønsted and Lewis acid sites were obtained, the amount of acid sites and the Lewis/Bronsted ratio (in the range of 1.9 to 7.6) being very dependent on the synthesis parameters. For example, the increase of the calcination temperature of aluminum hydroxide fluorides led to a decrease of both Lewis and Brønsted acid site but also an increase of the Lewis/Bronsted ratio. The most acid fluoride exhibited 542 mol g -1 of Lewis acid sites and 291 mol g -1 of Brønsted acid sites.These inorganic hydroxide fluorides were successively used as catalysts for the solventfree acylation of 2-methylfuran by acetic anhydride under mild conditions (50°C, atmospheric pressure) yielding selectively 2-acetyl-5-methylfuran. The activity of fluoride can be related to the amount of both Lewis and Brønsted acid sites. In general the higher these values, the greater the activity in acylation. A reaction mechanism was proposed involving a bi-acidic site which could be a Lewis acid site (unsaturated aluminum) in the vicinity of a Brønsted acid site.

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Supported palladium–copper catalysts: Preparation and catalytic behavior in hydrogen-related reactions

Cited by 17 publications

References 38 publications

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Theoretical and Applied Aspects of Hydrodechlorination Processes—Catalysts and Technologies

Heterogeneous Catalyzed Chemoselective Reductive Amination of Halogenated Aromatic Aldehydes

Inorganic hydroxide fluorides as solid catalysts for acylation of 2-methylfuran by acetic anhydride

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