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Dense Nonaqueous Phase Liquids (DNAPLs)
Chemistry and Behavior
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Halogenated Alkanes
Ethanes
1,1,2-Trichlorotrifluoroethane
1,1,2-Trichlorotrifluoroethane (TCTFE, CAS# 76-13-1) has a vapor pressure of 363 mmHg at 25oC (HSDB) and is a noncombustible liquid at normal temperatures (NIOSH 2005). The log Koc of TCTFE is about 2.59, the log Kow is 2.57 (Montgomery 1991), and the Henry's constant is 3.33 e-1 atm-m3/mole (Montgomery 1991)). The solubility of TCTFE is about 170 mg/L at 25oC, its specific gravity is about 1.56 at 25oC, and its vapor pressure is 363 mmHg at 25oC (HSDB).
The relatively low calculated Koc value for TCTFE in soil indicates that TCTFE is likely to move through soil and sediment (Howard 1993 and HSDB).
Volatilization is the most important removal process for TCTFE released to surface waters, and its half life in a typical river is estimated at about 4 hours (Howard 1993). Modeling information in the Hazardous Substances Data Bank (HSDB) estimates the half life of TCTFE in a model lake at 5 days
Because of the low Kow of this compound, bioaccumulation is expected to be low (Howard 1993 and HSDB). TCTFE is readily degraded by microbial action under anaerobic conditions to chlorotrifluoroethene, a vinyl chloride analog (van Agteren et al. 1998, Bagley et al. 2004, and HSDB). TCTFE does not degrade readily under aerobic conditions (HSDB and Reinhard and McCarty 1993). Pseudomonas putida has been observed to degrade TCTFE cometabolically under anaerobic conditions to various lower halogenated compounds (van Agteren et al. 1998)
As TCTFE will not degrade in the troposphere, diffusion from the troposphere to the stratosphere would be the sole removal mechanism (half life of 20 years). This compound will diffuse gradually into the stratosphere above the ozone layer, where direct photolysis from UV-C radiation will degrade it slowly, contributing to the catalytic removal of stratospheric ozone. The stratospheric lifetime of this compound ranges between 63 and 122 years (HSDB).
TCTFE is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups (HSDB).
References
Handbook of Environmental Fate and Exposure Data for Organic Chemicals, Volume IV
Howard, P.
Lewis Publishers, 578 pp, 1993
Handbook on Biodegradation and Biological Treatment of Hazardous Organic Compounds
van Agteren, M., S. Keuning, and D. Janssen.
Springer, 504 pp, 1998
1,1,2-TRICHLORO-1,2,2-TRIFLUOROETHANE (76-13-1)
Hazardous Substances Data Bank (HSDB)
TOXNET, National Library of Medicine Web site.
Long-term Chemical Transformation of 1,1,1-Trichloroethane (TCA) and Freon 113 under Aquifer Conditions
Reinhard, M. and P. McCarty.
U.S. EPA, National Center For Environmental Research, Grant R825689C044, Subproject 44, 1993.
View project summary
Under aerobic conditions, CFC 113 did not transform during a 4-year study.
Non-Enzymatic Degradation of Chlorofluorocarbon 113 Using Cyanocobalamin under Anaerobic Conditions
Bagley, D., I. Sutherland, and B. Sleep.
Journal of Environmental Engineering & Science 3(4):295-299(2004)
Freon 113 was degraded rapidly and completely in systems containing cyanocobalamin with titanium(III) citrate as the reductant. 1,2-Dichloro-1,1,2-trifluoroethane accounted for up to 25% of the degraded Freon 113. Chlorotrifluoroethene was also detected. View longer abstract
For Further Information
DNAPL Site Evaluation 
Cohen, R. and J. Mercer.
EPA 600-R-93-022, 369 pp, 1993
This document has a broad discussion of DNAPL site evaluation and contains a comprehensive table of physical properties of selected DNAPL chemicals, including TCFM, in its Appendix A.
