Pd‐Loaded Carbon Felt as the Cathode for Selective Dechlorination of 2,4‐Dichlorophenoxyacetic Acid in Aqueous Solution

Abstract

Electrocatalytic reductive dehalogenation of 2,4-dichlorophenoxyaceticacid (2,4-D) to phenoxyacetic acid in aqueous solution containing MeOH,trifluoroacetic acid, and tetraalkylammonium salt was studied. ATeflon-made two-compartment flaw-through cell with a permeable carbonfelt cathode and a platinum foil anode was employed. Several noblemetals were tested as electrocatalysts. Palladium-loaded carbon felt wasfound to be the most suitable cathode for selective dechlorination of2,4-D in aqueous solution. The preliminary electrolytic treatment ofPd/C cathode significantly enhanced its electrocatalytic activity toward2,4-D dechlorination. The reaction was hypothesized to proceed atcarbon-palladium interface areas through 4-chlorine cleavage to form2-chlorophenoxyacetic acid as the main reaction intermediate.