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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
Henry's law constant
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
07 December 2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
These substances exhibit similarity in their physicochemical properties such that they can be considered to constitute a chemical category. Data gaps for partitioning properties can therefore be addressed by read-across and/or trend analysis between category members.

Data source

Reference
Reference Type:
other: Read across from other internal studies
Title:
Unnamed
Year:
2012
Report date:
2012

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
other: Read across from category members
Deviations:
no
Principles of method if other than guideline:
Henry's Law Constant for category members PTBA and PFHp are used for a many-to-one read across to PTPA based on similarities in physical properties and chemistry.
GLP compliance:
not specified

Test material

Constituent 1
Reference substance name:
Perfluorotributyl amines (PTBA, CAS 1064698-37-8) and Perfluoroheptanes (PFHp, CAS 1064698-16-3)
IUPAC Name:
Perfluorotributyl amines (PTBA, CAS 1064698-37-8) and Perfluoroheptanes (PFHp, CAS 1064698-16-3)

Results and discussion

Henry's Law constant H
H:
140 000 - 166 000 dimensionless
Temp.:
23 °C
Atm. press.:
760 mm Hg
Remarks on result:
other: Upper limit defined by PTBA, lower limit defined by PFHp

Any other information on results incl. tables

Experimental water solubility and HLC data are available for two similar substances (perfluorotributyl amines (mixture); PTBA; CAS No. 1064698-37-8) and (perfluoroheptanes; PFHp; CAS No. 1064698-16-3). These two substances are similar to PTPA based on the types of chemical functional groups (perfluorinated alkyl groups); molecular weights (PTBA = 671 g/mol; PFHp = 388 g/mol; and PTPA =521 g/mol); vapor pressures (PTBA 0.02 mm Hg; PFHp = 51.89 mm Hg; and PTPA = 3.87 mmHg ug/L); and water solubilities (PTBA ≤ 0.0561 ug/L; PFHp = 11 ug/L; and PTPA = 0.381 ug/L). The respective dimensionless HLCs of these two substances are used to define the upper and lower bounds of the dimensionless HLC value which may be expected for PTPA. Based on the experimental dimensionless HLC of PTBA (>166000) and PFHp (140000) the anticipated range of the dimensionless HLC of PTPA is 140000 to 166000.

CAS No. 338-83-0 is a member of the Perfluorinated Organic Chemicals, C5-C18, category. All of these chemicals stem from the same manufacturing process, have similar physicochemical properties including high vapor pressure and low water solubility relative to the hydrocarbon analogs (e.g., hexanes v. perfluorohexanes), and also lack any chemically reactive groups, which forms the technical basis for the category. Members of this category are fully fluorinated, meaning that fluorine, rather than hydrogen, is bonded to all carbon atoms in the molecule. Fluorine is the most electronegative of the elements (fluorine has an electronegativity of 3.98 on the Pauling scale, as compared to 2.55 for carbon, 3.04 for nitrogen or 2.20 for hydrogen). This electronegativity is expected to dominate over all other aspects of substance chemistry and is the underlying basis for similarity of substances in this category. For example, strong electron withdrawing in perfluorinated tertiary amines results in a molecule with essentially lone pair influence, and which has chemistry more similar to a branched, perfluorinated alkane than any other structure. Because these substances exhibit similar physicochemical properties they can be considered to constitute a chemical category. The data gap for HLC can therefore be addressed by many-to-one read-across between category members.

Applicant's summary and conclusion

Conclusions:
The Henry’s Law constant (HLC) for PTPA was determined using a category approach wherein the experimental HLCs of two similar substances with similar physical properties are used to define the upper and lower bound of the dimensionless HLC range for PTPA. The resulting dimensionless HLC range is 140000 to 166000. This approach is considered reliable based on the reliability on the experimental values provided. Based on this value, the test substance is not expected to remain in aqueous solution in open systems and it will partition to the atmosphere.
Executive summary:

The Henry’s Law constant (HLC) for PTPA was determined using a category approach wherein the experimental HLCs of two similar substances with similar physical properties are used to define the upper and lower bound of the dimensionless HLC range for PTPA. The resulting dimensionless HLC range is 140000 to 166000. This approach is considered reliable based on the validity of the experimental values provided. Based on the anticipated dimensionless HLC range, the test substance is not expected to remain in aqueous solution in open systems and it will partition to the atmosphere.

The validity of this approach to categorically group these types of substances was determined to be reliable based on the similarity of chemical functional groups, the similarity of their molecular weights, related water solubilities, and related vapor pressures. This study is classified as an acceptable categorical HLC (dimensionless). It is pertinent to the fate of PFPA and may be used for risk analysis, classification and labelling, and PBT analysis.