Prediction of Redox Potentials and Isomer Distribution Yields for Reductive Dechlorination of Chlorobenzenes

Abstract

Gibbs free energies of reductive dechlorination processes of chlorobenzenes are calculated from thermodynamic data. The results are utilized to predict redox potentials and isomer distribution yields.

The model predicts a standard redox potential of 0.680 V for the reduction of hexachlorobenzene to pentachlorobenzene, tapering off to 0.535 V for the reduction of monochlorobenzene to benzene. It is shown that under anaerobic conditions, reductive dechlorination is more likely to occur, while aerobic conditions favour the formation of chlorophenols.

An isomer distribution yield is predicted for each of the reductive dechlorination processes of chlorobenzenes. Predicted yields correspond to experimental values within 10%. The model includes a possibility to establish a temperature dependence of the relative isomer yields.

Key Words:

• chlorobenzenes
• redox potentials
• isomer yields
• thermodynamics
• dechlorination