Metabolism of Pentachloroethane in the Mouse

Pentachloroethane was given subcutaneously to mice (1.1–1.8 g/kg) and the excretion was followed for 3 days. About one third of the dose (range 12–51 %) was expired unchanged. The metabolized part was excreted mainly as trichloroethanol (16–32 % of the dose) and trichloroacetic acid (9–18 %) in the urine. The expired air also contained trichloroethylene (2–16 %) and tetrachloroethylene (3–9 %) indicating both dechlorination and dehydrochlorination of pentachloroethane. The latter reaction was found to be non‐enzymatic. The metabolites were identified by paper chromatography, gas chromatography and mass spectrometry, and the Fujiwara reaction was used for the quantitative determination of trichloroacetic acid and of trichloroethanol after oxidation to this acid. At least part of the urinary metabolites must be formed via trichloroethylene and its metabolite chloral hydrate. The latter compound may also be formed from pentachloroethane by hydrolytic fission of carbon‐chlorine bonds.