KINETICS OF THE REDUCTION OF HEXACHLOROETHANE BY JUGLONE IN SOLUTIONSCONTAINING HYDROGEN

Hexachloroethane was converted to tetrachloroethene and unknown produc ts in solutions containing juglone and hydrogen sulfide. Measured rate s of disappearance in solutions containing hydrogen sulfide alone were approximately a factor of 10 slower than rates containing micromolar concentrations of juglone and hydrogen sulfide. Electrochemically-redu ced juglone was unreactive with respect to hexachloroethane reduction. Reaction of hexachloroethane with polysulfides produced in the reacti on of elemental sulfur with hydrogen sulfide in the experimental solut ions also could not account for the rate observed in solutions contain ing juglone and hydrogen sulfide. Evidence is provided to indicate the reaction of hexachloroethane with the Michael addition product of hyd rogen sulfide and juglone. No conclusions can be drawn from the presen t results as to whether the reaction mechanism is a one- or a two-elec tron transfer. This study points out the importance of the geochemistr y of sulfur and organic matter in the transformation of halogenated al kane pollutants in reducing environments.