Electroreduction of Hexachlorobenzene in Micellar Aqueous Solutions of Triton-SP 175

The electrochemical reduction of hexachlorobenzene (HCB) has been studied in micellar aqueous solutions using Triton-SP 175 which, unlike conventional surfactants, is acid-labile. At pH <3, the hydrophobic residue cleaves from the hydrophilic chain, leaving a solution without surface-active properties and allowing recovery of the electrolysis products from the solution. A micellar solution containing 0.1% v/v Triton-SP 175 and 1% v/v heptane as cosolvent was indefinitely stable in the presence of 0.05 M sodium sulfate as an environmentally friendly supporting electrolyte. Electrolytic dehalogenation to less chlorinated benzenes was studied at a wide variety of cathodes; in all cases a quantitative material balance of phenyl residues was achieved. Lead was the preferred cathode in terms of both the degree of dechlorination achieved and the current efficiency.