Fundamental and applied studies on the electrochemical hydrodehalogenation of halogenated phenols at a palladised titanium electrode Original Research Article

In situ Fourier transform infrared studies have shown that the electrochemical hydrodehalogenation (HDH) of a wide range of halogenated phenols to give the phenolate anion was observed through a common adsorbed intermediate at a palladium catalysed titanium electrode. The mechanism of the reduction may be represented as a sequence of electron additions and halide expulsions leading, via the intermediate radical, to product. The electrochemical HDH of halogenated phenols in aqueous solution was studied at ambient temperature and atmospheric pressure in a two-compartment H-cell reactor and a solid polymer electrolyte reactor, as well as with in situ Fourier transform infrared (FTIR) spectroscopy. Complete dehalogenation of 10 mM halogenated phenol solutions was observed with current efficiencies up to 90% in the H-cell, whilst current efficiencies up to 50% were observed using the solid polymer electrolyte reactor.