Journal of Electroanalytical Chemistry, Vol.661, No.1, 39-43, 2011
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
A comparative study of the cobalt(I) salen-catalyzed electrochemical reduction of 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) in both carbon dioxide- and argon-saturated dimethylformamide (DMF) containing tetra-n-butylammonium tetrafluoroborate (TBABF(4)) has been carried out by means of cyclic voltammetry with a glassy carbon electrode. Catalytic reduction of CFC-113 by cobalt(I) salen appears to be more efficient in a carbon dioxide-saturated medium. Chlorotrifluoroethene (a degradation product of CFC-113) is also more efficiently reduced by electrogenerated cobalt(I) salen in the presence of carbon dioxide. No evidence for the cobalt(I) salen-catalyzed reduction of trifluoroethene (another degradation product of CFC-113) has been seen. Preliminary bulk electrolyses of cobalt(II) salen-CFC-113 mixtures in a carbon dioxide-saturated medium have indicated the formation of chlorotrifluoroethene, trifluoroethene, and 1,1,1,2-tetrafluoroethane. However, these three compounds do not account for all of the original CFC-113: therefore, future work will focus on the possible production of 3,3-dichloro-2,2,3-trifluoropropanoic acid and 2,3,3-trifluoroacrylic acid that might arise via carboxylation of anionic intermediates derived from the reduction of CFC-113. Furthermore, ultraviolet-visible spectrophotometry has confirmed that cobalt(I) salen and carbon dioxide interact to preserve the fidelity of the catalyst. (C) 2011 Elsevier By. All rights reserved.
Keywords:Cobalt(I) salen;Carbon dioxide;1,1,2-Trichloro-1,2,2-trifluoroethane (CFC-113);Catalytic reduction;Glassy carbon electrode