Journal of Electroanalytical Chemistry, Vol.772, 66-72, 2016
Catalytic reduction of 4,4'-(2,2,2-trichloroethane-1,1-diyl)bis (methoxybenzene) (methoxychlor) with nickel(I) salen electrogenerated at reticulated vitreous carbon cathodes
Methoxychlor [or 4,4'-(2,2,2-trichloroethane-1,1-diyl)bis(methoxybenzene)], a common environmental pollutant, has been catalytically reduced with nickel(() salen electrogenerated in situ at carbon cathodes in dimethylformamide (DMF) containing 0.050 M tetra-n-butylammonium tetrafluoroborate (TBABF(4)). Cyclic voltammograms for reduction of nickel(II) salen in the presence of various concentrations of methoxychlor provide evidence for catalytic reduction. Cathodic peak currents for the nickel(II) salen-nickel(I) salen redox couple increase in proportion to the concentration of methoxychlor, whereas the anodic peak current associated with re oxidation of nickel(I) salen diminishes; in addition, a cathodic prepeak appears at higher concentrations of methoxychlor. Controlled-potential (bulk) electrolyses of nickel(II) salen at reticulated vitreous carbon cathodes in the presence of methoxychlor allowed the n value for reduction of methoxychlor to be determined. With the aid of gas chromatography-mass spectrometry, major electrolysis products have been identified as 4,4'-(2-chloroethene-1,1-diyl)bis(methoxybenzene) and 4,4'-(ethene-l,l-diyl)bis(methoxybenzene), and the product distribution was determined by means of gas chromatography. Adducts arising from the combination of fragments derived from methoxychlor and DMF have also been detected and confirmed, and a mechanistic scheme is proposed to account for the various products. (C) 2016 Elsevier B.V. All rights reserved.