Reduction electrochimique du trichloro-1,1,2-trifluoroethane: Effet catalytique de l'ion ammonium

Savall, A.; Abdelhédi, Ridha; Dalbera, Subrata; Bouguerra, M. L.

doi:10.1016/0013-4686(90)87072-a

Cited by 13 publications

(13 citation statements)

References 10 publications

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“…In particular, NH, and tetraalkylammonium ions significantly facilitate the electroreduction of CFC 113 to CTFE. 12,21 CTFE is an industrial monomer which can be used to produce oils and waxes. 2 3 On the other hand, the electroreduction of CFC 114 (1,2-* Electrochemical Society Active Member.…”

Section: Introductionmentioning

confidence: 99%

Palladium‐Assisted Electrodehalogenation of 1,1,2‐Trichloro‐1,2,2‐trifluoroethane on Lead Cathodes Combined with Hydrogen Diffusion Anodes

Cabot

Centelles

Segarra

et al. 1997

J. Electrochem. Soc.

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In this work, the efficiency and product formation in the electroreduction of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC 113) to obtain completely dechlorinated products has been studied using constant-current electrolysis at different current densities, gas chromatography, scanning electron microscopy, and energy dispersive x-ray. While chlorotrifluoroethene was the main product obtained from CFC 113 in MeOH-water solutions containing NH 4 C1, different and suitable conditions which lead to its complete dechlorination are described in this paper. In the presence of small amounts of Pd 2+ in solution, a very thin film of Pd black was electrodeposited on the Pb cathode and the efficiency of the CFC 113 electroreduction was about 98%. The efficiency was much smaller and the product composition very different in the absence of Pd 2+ in solution, even in the presence of Pd black electrodeposited on the cathode. In the presence of Pd 2+ , the main products in the gas phase were difluoroethene and trifluoroethene. Small amounts of 1,2-dichloro-1,1,2-trifluoroethane, chlorotrifluoroethene, difluoroethane, and fluroethane were also present in the gas phase. The liquid composition was enriched in the less volatile compounds. A possible reaction pathway involving the removal of halides by successive reactions is discussed. The anode employed in these experiments was a thin Pd foil with electrodeposited Pd black, which permitted hydrogen diffusion and its further oxidation to H + . Because of this reaction, contamination of the workingelectrolyte by other oxidation products such as C12 or MeOH derivatives were avoided. This system allows new electrosynthetic processes along with CFC electrodegradation.

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Section: Introductionmentioning

confidence: 99%

Palladium‐Assisted Electrodehalogenation of 1,1,2‐Trichloro‐1,2,2‐trifluoroethane on Lead Cathodes Combined with Hydrogen Diffusion Anodes

Cabot

Centelles

Segarra

et al. 1997

J. Electrochem. Soc.

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“…5͒. CTFE is considered to proceed from the two-electron reduction of CFC 113 [6][7][8][9][10][11][12][13][14][15] and it may also lead to TFE by a further two-electron reduction. 1 Palladium ion may catalyze the conversion of ethylene derivatives such as CTFE and TFE to finally form DFE.…”

Section: Resultsmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] They may have industrial interest. For example, some hydrofluorocarbons ͑HFCs͒ such as difluoromethane ͑HFC 32͒ may be applied as refrigerants.…”

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confidence: 99%

Electrodegradation of Chlorofluorocarbons 11 and 113 at Small Concentrations in Closed Cells

Cabot

Segarra

Casado³

2003

Electrochem. Solid-State Lett.

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The electrodegradation with electrosynthetic possibilities of trichlorofluoromethane ͑CFC 11͒ and 1,1,2-trichloro-1,2,2-trifluoroethane ͑CFC 113͒ in acetate-containing methanol-water mixtures, has been studied using constant-potential electrolysis and gas chromatography. A closed cell with a Pb cathode and a Pd-based hydrogen diffusion anode, together with small concentrations of CFCs were employed to follow their conversion. The conversion of CFC 11 into the most dechlorinated derivatives increased with time. Partially and completely dechlorinated ethylene derivatives were obtained in the electroreduction of CFC 113, their relative amounts depending on the Pd 2ϩ content of the electrolyte. In the negative part, some cathode corrosion during the process was evidenced.Different dechlorinated derivatives including completely dechlorinated compounds have been obtained from the electroreduction of chlorofluorocarbons ͑CFCs͒. 1-18 They may have industrial interest. For example, some hydrofluorocarbons ͑HFCs͒ such as difluoromethane ͑HFC 32͒ may be applied as refrigerants. Chlorotrifluoroethene ͑CTFE͒ and tetrafluoroethene are interesting in the polymer industry. The use of Pd 2ϩ in methanol-water mixtures containing ammonium chloride allowed to obtain difluoroethene ͑DFE͒ and trifluoroethene ͑TFE͒ from 1,1,2-trichloro-1,2,2-trifluoroethane ͑CFC 113͒ via 1,2-dichloro-1,2,2-trifluoroethane ͑1,2-DCTFE͒. 1,16,17 It was also found that electrodeposited Pd slightly favored the conversion of trichlorofluoromethane ͑CFC 11͒ in fluoromethane ͑FM͒ in front of dichlorofluoromethane ͑DCFM͒ and chlorofluoromethane ͑CFM͒. 18 Previous works showed that the use of a hydrogen diffusion anode avoids the electrolyte oxidation ͑and so, polluting byproducts͒ and allows for its operation without separators ͑thus saving energy and cost of membranes͒. 1,16-18 The cell employed allowed to collect the gas evolved on the cathode and current efficiencies of about 95% were obtained in the electroreduction of CFCs 11 and 113. The electrolyte was ammonium chloride in methanol-water mixtures, although other electrolytes such as potassium acetate have also been employed efficiently. 15 The concentration of CFC was near saturation and therefore, it is not surprising that the less dechlorinated derivatives were mainly formed. In addition, note that possible cathode corrosion has been scarcely examined. The formation of tetraethyllead during the electroreduction of haloethanes on Pb in organic solvents 19 and its corrosion during the electroreduction of Clcontaining saturated hydrocarbons in alkaline media 20 points out to this possibility. Detection of cathode corrosion is interesting because of its incidence on the cathode stability and electrolyte contamination.This work explores the electroreduction of small amounts of CFCs 11 and 113 on Pb cathodes in acetate-containing methanolwater mixtures to study their conversion into the most dechlorinated derivatives. A closed cell has been employed for this purpose and both the gas and the liquid have been ...

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“…Although direct electrochemical reduction of CFC-113 has been investigated [3,4], catalytic reduction has proven to be more promising due to its lower energy expenditure and its improved product selectivity. In previous work, Savall and co-workers [5] employed copper cathodes in NH 4 Cl-containing methanol-water mixtures for the conversion of CFC-113 to chlorotrifluoroethene (CTFE). Recently, Titov et al [6] also obtained CTFE as a product of the nickel(I)-catalyzed reduction of CFC-113 at a platinum cathode.…”

Section: Introductionmentioning

confidence: 99%

Cyclic voltammetric and spectrophotometric investigation of the catalytic reduction of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) by electrogenerated cobalt(I) salen in dimethylformamide saturated with carbon dioxide

Skljarevski

Peverly

Peters

2011

Journal of Electroanalytical Chemistry

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Reduction electrochimique du trichloro-1,1,2-trifluoroethane: Effet catalytique de l'ion ammonium

Cited by 13 publications

References 10 publications

Palladium‐Assisted Electrodehalogenation of 1,1,2‐Trichloro‐1,2,2‐trifluoroethane on Lead Cathodes Combined with Hydrogen Diffusion Anodes

Palladium‐Assisted Electrodehalogenation of 1,1,2‐Trichloro‐1,2,2‐trifluoroethane on Lead Cathodes Combined with Hydrogen Diffusion Anodes

Electrodegradation of Chlorofluorocarbons 11 and 113 at Small Concentrations in Closed Cells

Cyclic voltammetric and spectrophotometric investigation of the catalytic reduction of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) by electrogenerated cobalt(I) salen in dimethylformamide saturated with carbon dioxide

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