Trichloroethylene and tetrachloroethylene (TCE and PCE) are groundwater pollutants that are used as dry cleaning fluids and industrial degreasers. The EPA has recently classified both these compounds as human carcinogens, making it important to develop a method of detoxification. One method of detoxifying these compounds is through dechlorination, forming the non-carcinogenic compound ethylene. There are two naturally occurring metalloenzymes, cobalamin and cofactor F430, which have been shown to dechlorinate TCE and PCE into ethylene. We are studying these compounds because the reactions occur at benign conditions, making them ideal for an environmentally-friendly treatment option. But, the exact reaction mechanisms for these molecules are not yet understood. To better understand the reaction mechanisms, two model compounds were studied: [Co(TMC)Cl]+ and [Ni(cyclam)]2+. We spent the summer studying the reactivities of these model compounds with PCE and TCE. We reacted [Co(TMC)Cl]+ with PCE in acetonitrile, monitoring using UV-vis spectroscopy and GC-MS. The UV-vis kinetic data indicated that a new compound was being formed, and GC-MS analysis confirmed that TCE was produced. [Ni(cyclam)]2+ dechlorinated PCE more effective than [Co(TMC)Cl]+, and this reaction was monitored by GC-MS. In the future, we plan to optimize our reaction conditions and explore the dehalogenation of TCE and dichloroethylene.

Dechlorination abilities of biomimetic compounds

253rd National Meeting (2017)

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