Electrochemical reduction of benzyl halides at a silver electrode

Isse, Abdirisak Ahmed; Giusti, Alessio De; Gennaro, Armando; Falciola, L.; Mussini, Patrizia R.

doi:10.1016/j.electacta.2006.01.039

Cited by 126 publications

(116 citation statements)

References 32 publications

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“…Thus, in the case of cathodic materials possessing catalytic activities such as Ag [13][14][15][16][19][20][21][22], Cu [21,23,24] and Pd [21,25,26], there are significant interactions between the electrode surface and, possibly the reagents, products, and mainly the activated complex [21], resulting in a lowering of the activation energy of the ET. As a consequence, the reduction process occurs at more positive potentials (less overpotential is required) with respect to a non-catalytic electrode.…”

Section: Aliphatic Halidesmentioning

confidence: 99%

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Electrocatalysis and electron transfer mechanisms in the reduction of organic halides at Ag

et al. 2009

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The reductive cleavage of a series of organic halides, including both aromatic and aliphatic compounds, has been investigated in acetonitrile at glassy carbon and silver electrodes. Ag exhibits extraordinary electrocatalytic activities for the reduction of most of the investigated halides. During the reductive cleavage of a carbon-halogen bond, electron transfer (ET) and bond breaking may occur either in a single step or in two distinct steps. The compounds examined in this study are representative of both dissociative electron transfer (DET) mechanisms. In general a link between the DET mechanism and electrocatalysis at Ag is observed for the whole set of data. There is no catalysis at all when the ET involves a substituent that gives a stable radical anion. Furthermore, there is no catalysis for all aromatic chlorides. Instead, a remarkable electrocatalysis is observed for all compounds undergoing a concerted DET mechanism, regardless of the nature of the halogen atom.

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Section: Aliphatic Halidesmentioning

confidence: 99%

“…We have been active in the field of electrocatalytic activation of organic halides for several years. In particular, we focused our attention on silver [9][10][11][12][13][14], which is among the best catalytic materials for the reduction of RX [15].…”

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Electrocatalysis and electron transfer mechanisms in the reduction of organic halides at Ag

et al. 2009

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“…An increasing number of studies has demonstrated that organic chlorides are easier to reduce at silver cathodes than at carbon electrodes. [18][19][20] Recently, it has been shown in our laboratory that the position and identity of the halogen atom affect the reduction potential and mechanism. 21,22 Research from the groups of Isse 23,24 and Amatore 25 has provided further insight concerning the mechanisms of electroreductive carbon-chlorine bond cleavage at silver cathodes; it has been determined that activated species adsorb onto the silver surface, thereby promoting the observed catalytic effects.…”

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confidence: 99%

Direct Electrochemical Reduction of 4,4^′-(2,2,2-Trichloroethane-1,1-diyl)bis(methoxybenzene) (Methoxychlor) at Carbon and Silver Cathodes in Dimethylformamide

McGuire

Peters

2016

J. Electrochem. Soc.

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Cyclic voltammetry and controlled-potential (bulk) electrolysis have been employed to investigate the electrochemical reduction of 4,4 -(2,2,2-trichloroethane-1,1-diyl)bis(methoxybenzene), commonly known as the pesticide methoxychlor, at glassy carbon and silver cathodes in dimethylformamide (DMF) containing 0.050 M tetra-n-butylammonium tetrafluoroborate (TBABF 4 ). Reduction of methoxychlor at both glassy carbon and silver shows four voltammetric peaks, the first three of which are associated with cleavage of carbon-chlorine bonds; the fourth peak is assigned to reduction of 4,4 -(ethene-1,1-diyl)bis(methoxybenzene). Bulk electrolyses of methoxychlor at reticulated vitreous carbon and silver mesh cathodes at potentials corresponding to each of the first three voltammetric peaks were conducted; coulometric n values and product distributions (determined by means of GC and GC-MS techniques) depend on potential. In particular, two completely dechlorinated products, namely 4,4 -(ethane-1,1-diyl)bis(methoxybenzene) and 4,4 -(ethene-1,1-diyl)bis(methoxybenzene) have been identified and quantitated. A mechanistic scheme is proposed to account for the formation of the various products. When global use of the infamous pesticide 4,4 -(2,2,2-trichloroethane-1,1-diyl)bis(chlorobenzene) (1)-known more familiarly as DDT-was restricted, a close relative, namely 4,4 -(2,2,2-trichloroethane-1,1-diyl)bis(methoxybenzene) (2) or methoxychlor, became a temporarily popular replacement. Unfortunately, when concerns about the toxicity of 2 arose, it was banned in the European Union in 2002 and became unregistered in the United States in 2003. However, in other parts of the world, 2 is still employed as an agricultural pesticide and for home applications in the treatment of flea and fly infestations.Like many members of the family of halogenated pesticides, methoxychlor degrades very slowly in the environment, which allows for its transport and subsequent detection in Arctic samples far from the original point of use.1 For hydrolytic degradation pathways in aquatic systems of pH 6-9, the half-life is approximately one year, and the resulting olefinic metabolite degrades even more slowly.2 When exposed to sunlight, this olefin derivative undergoes an interesting photoisomerization in water.3 Sunlight increases the photolysis rate, so that the half-life at the surface of distilled water is closer to 4.5 months, and even faster in natural waters where half-lives of only 2-5 h are seen. 4 Biological degradation of methoxychlor results in the loss of one chlorine as well as demethylation of the hydroxylbenzene moieties.5 Uptake of methoxychlor in a model ecosystem has also been examined; whereas methoxychlor was found to be in a dynamic state in fish, it accumulated in snails. Furthermore, incubated mouse livers were unable to metabolize methoxychlor and 97% was recovered. 6 Concerns about the accumulation of methoxychlor in humans prompted studies conducted in the agricultural region of Spain * Electrochemical Society Student Member. * * E...

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“…Silver is presently considered as a fascinating metal for its catalytic properties especially in the domain of the scission of carbon-halogen bonds [6,7], and despite its perspective capacities to act as a reducing entity, attempts to modify surfaces or to insert ions into Ag matrixes do not presently appear to have been achieved.…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

Electrochemical insertion of CO 2 into silver in a large extent

Simonet

2015

Electrochemistry Communications

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The reduction of solutions of carbon dioxide (saturated at the room temperature in organic polar solvents such as acetonitrile, AN, or N,N-dimethylfomamide, DMF, containing tetraalkylammonium salts TAAX) was achieved at smooth silver electrodes. Under these conditions, reduction steps were obtained beyond -1.7 V vs Ag / AgCl with exact potentials depending on the size of TAA + cations. An unexpected behaviour is noticeable with tetramethylammonium salts (TMA + X -) leading to a progressive electrode inhibition upon scans or fixed potential electrolysis at E < -2V. These results are in agreement with the formation of a thick layer of the form {Ag-CO 2 -,TMA + } strongly sensitive to di-oxygen, water, organic π-acceptors; this layer is considered as a reducing reagent of low chemical stability and can be oxidized before silver. Placed under pure argon atmosphere, the layer decomposes -presumably by instability of TMA + in reducing media that permits trapping of large superficial amounts of CO 2 in the material supposing the formation of multi-layers of CO 2 (up to 5´10 -6 mol cm -2 ). These novel {silver-CO 2 } materials could be seen as dual catalytic-electrophilic electrodes.

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Electrochemical reduction of benzyl halides at a silver electrode

Cited by 126 publications

References 32 publications

Electrocatalysis and electron transfer mechanisms in the reduction of organic halides at Ag

Electrocatalysis and electron transfer mechanisms in the reduction of organic halides at Ag

Direct Electrochemical Reduction of 4,4^′-(2,2,2-Trichloroethane-1,1-diyl)bis(methoxybenzene) (Methoxychlor) at Carbon and Silver Cathodes in Dimethylformamide

Electrochemical insertion of CO 2 into silver in a large extent

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Electrochemical reduction of benzyl halides at a silver electrode

Cited by 126 publications

References 32 publications

Electrocatalysis and electron transfer mechanisms in the reduction of organic halides at Ag

Electrocatalysis and electron transfer mechanisms in the reduction of organic halides at Ag

Direct Electrochemical Reduction of 4,4′-(2,2,2-Trichloroethane-1,1-diyl)bis(methoxybenzene) (Methoxychlor) at Carbon and Silver Cathodes in Dimethylformamide

Electrochemical insertion of CO 2 into silver in a large extent

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Direct Electrochemical Reduction of 4,4^′-(2,2,2-Trichloroethane-1,1-diyl)bis(methoxybenzene) (Methoxychlor) at Carbon and Silver Cathodes in Dimethylformamide