Electrochimica Acta, Vol.137, 511-517, 2014
Reductive dehalogenation of 1,3-dichloropropane by a [Ni(tetramethylcyclam)]Br-2-Nafion (R) modified electrode
Dechlorination reaction of 1,3-dichloropropane, a contaminant solvent, was investigated by electrochemical reduction in aqueous medium using a Ni(tmc)Br-2 complex, known as effective catalyst in dehalogenation reactions. The catalytic activity of the complex was first investigated by cyclic voltammetry and flow homogeneous redox catalysis using a graphite felt as working electrode. A total degradation of 1,3-dichloropropane was obtained after 5 h of electrolysis with a substrate/catalyst ratio of 2.3. The concentration of chloride ions determined by ion chromatography analysis showed a dechlorination yield of 98%. The complex was then immobilized on the graphite felt electrode in a Nafion (R) film. Flow heterogeneous catalytic reduction of 1,3-dichloropropane was then carried out with the [Ni(tmc)]Br-2-modified Nafion (R) electrode. GC analyses underlined the total degradation of the substrate in only 3.5 h with a substrate/catalyst ratio of 100. A dechlorination yield of 80% was obtained, as seen with ion chromatography analyses of chloride ion. Comparison of both homogeneous and heterogeneous reactions highlighted the interest of the [Ni(tmc)]Br-2-modified Nafion (R) electrode that led to a higher stability of the catalyst with a turnover number of 180 and a higher current efficiency. (C) 2014 Elsevier Ltd. All rights reserved.