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Perfluoromethylmorpholine (PMM) is a member of the Perfluorinated Organic Chemicals, C5-C18 category. It is a liquid at room temperature with a vapor pressure of 29.02 kPa (217.7 mm Hg) at 20°C.  PMM water solubility is 758 µg/L at 23 °C.  Its measured Henry’s law constant (expressed as the ratio of vapor phase partial pressure of PMM over aqueous phase concentration) is 171 atm∙m³/mol at 22 °C. Releases of PMM are expected to be to the atmosphere based upon its intended uses.  Fugitive emissions may occur at transfer points.  During routine use, there is no anticipated release to water or wastewater in the EU.  The high vapor pressure, low water solubility and high Henry’s law constant combine to move PMM from any terrestrial compartment into the atmosphere.  A soil volatilization half-life of 66.1 ± 16 min was measured in a laboratory setting, indicating very rapid evolution from soil to air in the terrestrial compartment.  Once in the atmospheric compartment, this compound will not partition to terrestrial or aquatic compartments based on the same properties.  Therefore, this compound will remain in the atmosphere when released from industrial applications.  The molecule contains no hydrolysable groups and is not biodegradable.  Degradation in the environment is expected to be by direct photolysis in the upper atmosphere.  An additional pathway may be indirect photolysis by singlet atomic oxygen,O(1D), in the stratosphere. An overall lifetime in the range of 1500-4000 years is expected through these processes.  The ultimate degradation products are hydrofluoric acid (HF, CAS# 7664-39-3), carbon dioxide, water and oxides of nitrogen.  These materials are miscible 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.

 

As PMM is a highly fluorinated substance, global warming and ozone depletion potentials may be of interest.  USEPA states flatly 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 PMM 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.  PMM has an estimated GWP of 8380 over a 100-year integrated time horizon.

 

PMM is not expected to partition to moist soils or surface waters.  Upon accidental, direct release of PMM to the aquatic compartment, the chemical is expected to volatilize rapidly.  Members of the Perfluorinated Organic Chemicals, C5-C18 category did not show signs of biodegradation in reliable Closed Bottle (BOD) tests.  In addition, a headspace biodegradation (OECD310) assay of category member FC-770 (perfluoro-N-C1,3-alkylmorpholines) showed no biodegradation.  However, non-biodegradability of PMM in aquatic or terrestrial compartments is expected to be not relevant due to rapid volatilization from soil and water.

 

PMM is expected to have little potential to bioaccumulate.  Given its extremely short half-life due to volatilization, it will not exist in aquatic environments or organisms for a sufficient time to allow partitioning into lipid-containing tissues or to allow testing of bioconcentration under relevant conditions.

 

Please see IUCLID section 13 for a full matrix of environmental fate and pathway data for members of the Perfluorinated Organic Chemicals C5-C18 category

 

              References

 

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