1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane

Endpoint summary

Additional information

HFE s-601 is a segregated hydrofluoroether. It is a liquid at room temperature with a vapor pressure of 6.25 kPa (46.9 mm Hg) at 20 °C and a water solubility of 295 µg/L at 30 °C. Its measured Henry’s law constant is 67 atm∙m³/mol at 22 °C. The vapor pressure, low water solubility and high Henry’s law constant combine to move HFE s-601 from any surface compartment into the atmosphere. Once in the atmospheric compartment, this compound will not partition to terrestrial or aquatic compartments based on the same properties. HFE s-601 was not degraded in either of two OECD301D tests, but was not inhibitory to biodegradation. No biodegradation of HFE s-601 is expected under environmental conditions. Degradation in the environment is expected to occur by indirect photolysis in the troposphere, for which an overall lifetime of 3.8 years was measured. The expected final degradation products are hydrofluoric acid (HF, CAS# 7664-39-3), trifluoroacetic acid (TFA, CAS# 76-05-1) and carbon dioxide. These materials are highly soluble in water and are completely ionized in rainwater. They are expected to undergo wet deposition with no further significant transformation upon return to the troposphere.

HFE s-601 has a measured log Kow of 4.3. Two bioconcentration studies were done, however owing to non-standard and non-representative test conditions these were deemed unreliable and are not considered further.  However, HFE s-601 is expected to have little potential to bioaccumulate. Given its extremely short expected half-life in the aquatic compartment due to volatilization, it will not exist in aquatic environments or organisms for a sufficient time to allow partitioning into lipid tissues or testing of bioconcentration under relevant conditions.

As HFE s-601 is a highly fluorinated substance, global warming and ozone depletion potentials may be of interest. USEPA states that hydrofluorocarbons do not deplete ozone because they lack chlorine or bromine. Fluorine radicals do not contribute to ozone depletion because of fast quenching of F* by water or hydrogen donors, slow reaction of FO* radicals with oxygen, and obligate reformation of F* in the pathway (1). F* radicals are rapidly and irreversibly removed from the atmosphere after quenching as HF. Therefore, neither HFE s-601 nor any of its acidic photodegradation products contribute to ozone depletion. Global warming potential depends on three factors: absorption of infrared radiation, area of the spectrum the absorption occurs and lifetime of the material in the atmosphere. HFE s-601 has an estimated GWP of 310 over a 100-year integrated time horizon (2).

Reference:

1) A.J. Colussi, M.A. Crela. 1994. Rate of the reaction between oxygen monofluoride and ozone. Implications for the atmospheric role of fluorine. Chem. Phys. Lett. Vol. 229, pp. 134-138.

2) Registrant internal report.