Reduction of trichloroethylene by outer-sphere electron-transfer agents

A series of well-characterized outer-sphere electron-transfer agents were used to study the reduction of trichloroethylene (TCE). Through comparison of the final product ratios of cis-dichloroethylene (cDCE) to trans-dichloroethylene (tDCE) of the outer-sphere reductants to that observed for vitamin B12, it was found that an outer-sphere electron-transfer mechanism is not the likely major pathway in the reduction of TCE by B12. The results provide kinetic support for a two-step reduction mechanism by outer-sphere reductants that involves both vinyl radicals and vinyl anions. The results suggest that the [cDCE]:[tDCE] ratio can be used as a diagnostic for the mechanism of TCE reduction. Copyright © 2005 American Chemical Society.