Electrochemically reductive dechlorination of chlorophenol using nickel and zinc electrodes

Electrochemically reductive dechlorination of chlorophenols on zinc and nickel electrodes in propylene carbonate solvent is investigated. The reductive dechlorination of a variety of chlorophenols on the zinc electrode occurred at different potentials. For pentachlorophenol, two reductions were found at −2.4 V and −1.7 V. Two reductions were also found at −2.7 V and −1.95 V for 2,3,4,6-tetrachlorophenol. Only one reduction was found for 2,4,5-trichlorophenol, 2,4-dichlorophenol and 2-chlorophenol, it was observed at −2.2 V, −2.35 V and −2.5 V respectively. The electrolysis of controlled potential was held at −2.7 V. 2,3,4,6-tetrachlorophenol was dechlorinated and trichlorophenols and dichlorophenols were the major intermediate products. 2-chlorophenol was also dechlorinated at the potential of −2.7 V. The result shows chlorophenols can completely dechlorinate on the zinc cathode.