Reaction mass of 1,1,2,2,3,3,3-heptafluoro-N-(heptafluoropropyl)-N-(pentafluoroethyl)propan-1-amine and 1,1,2,2,3,3,3-heptafluoro-N-(heptafluoropropyl)-N-(trifluoromethyl)propan-1-amine and 1,1,2,2,3,3,3-heptafluoro-N,N-bis(heptafluoropropyl)propan-1-amine

Henry's Law constant

Administrative data

Endpoint:

Henry's law constant

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Remarks:

Data from valid studies under GLP

Justification for type of information:

MTDID 50908 is a member of the Perfluorinated Organic Chemicals, C5-C18, category. It consists predominantly of a mixture of C7-C9 perfluorinated tertiary amines, with variety of minor impurities that are also within the category definition and are considered to be category members.  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 no 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.

Data source

Reference

Reference Type:

other: read across from other internal studies

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: REACH Guidance on QSARs and grouping of chemicals

Version / remarks:

May/July 2008

Deviations:

no

GLP compliance:

no

Remarks:

Source data were GLP compliant

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 1,1,2,2,3,3,3-heptafluoro-N-(heptafluoropropyl)-N-(pentafluoroethyl)propan-1-amine and 1,1,2,2,3,3,3-heptafluoro-N-(heptafluoropropyl)-N-(trifluoromethyl)propan-1-amine and 1,1,2,2,3,3,3-heptafluoro-N,N-bis(heptafluoropropyl)propan-1-amine

EC Number:

920-778-3

Cas Number:

2176446-38-9

Molecular formula:

constituents: CnF(2n+3)N with n= 7-9

IUPAC Name:

Reaction mass of 1,1,2,2,3,3,3-heptafluoro-N-(heptafluoropropyl)-N-(pentafluoroethyl)propan-1-amine and 1,1,2,2,3,3,3-heptafluoro-N-(heptafluoropropyl)-N-(trifluoromethyl)propan-1-amine and 1,1,2,2,3,3,3-heptafluoro-N,N-bis(heptafluoropropyl)propan-1-amine

Test material form:

liquid

Details on test material:

- Name of test material (as cited in study report): MTDID 50908
- Physical state: Colourless liquid
- Storage condition of test material: At room temperature

Specific details on test material used for the study:

Readacross is from category members:
Perfluoroheptanes, PFHp, CAS# 1064698-16-3
Perfluorotripropylamine, PTPA, CAS# 338-83-0
Perfluorotributyl amines, PTBA, CAS# 1064698-37-8
Perfluoro-N-C1,3-alkyl morpholines, FC-770, CAS# 1093615-61-2

Results and discussion

Henry's Law constant H

Henry's Law constant H 1

Key result

H:

ca. 3 400 - ca. 4 020 atm m³/mol

Temp.:

22 °C

Remarks on result:

other: lower limit defined by perfluoroheptanes, upper limit by perfluorotributyl amines

Henry's Law constant H 2

H:

ca. 1 030 atm m³/mol

Temp.:

22 °C

Remarks on result:

other: data for category member FC-770

Remarks:

Major constituent is an impurity of MTDID 50908

Any other information on results incl. tables

Experimental HLC data are not available for major constituents of MTDID 50908. Readacross by bracketting using other category members was therefore used to establish a range for HLC of MTDID 50908. Among category members PFHp and PTBA best bracket MTDID 50908 with regard to molecular weight range, vapor pressure, water solubility, and log Kow. In addition, PTBA is a perfluorinated tertiary amine, with PFHp as a perfluorinated alkane representing the perfluoroalkyl side-chains of the amines. The HLC values for these two category members were therefore used to establish upper and lower bounds for the major constituents of MTDID 50908.

An impurity of MTDID 50908, 2,2,3,3,5,5,6,6-octafluoro-4-(1,1,1,2,3,3,3-heptafluoropropan-2-yl)morpholine, is the predominant constituent of the category member Perfluoro-N-C1,3-alkyl morpholines (FC-770), CAS# 1093615-61-2. Physical-chemical data for FC-770 indicate that it is considerably more water soluble than the perfluorinated tertiary amines which are the predominant constituents of MTDID 50908. The HLC of FC-770 is not therefore not representative of the predominant constituents. However, it may be used to provide an indication of the HLC for the more-soluble minor impurities found in MTDID 50908.

Applicant's summary and conclusion

Conclusions:

Henry's Law constant of MTDID 50908: 3400 – 4020 atm∙m³/mol at 22 °C for predominant components, by readacross from category members. Minor impurities with higher solubility are expected to have lower HLC values (ca. 1030 atm∙m³/mol at 22 °C)

Executive summary:

The Henry’s Law constant (HLC) for MTDID 50908 was determined using a category approach wherein the experimental HLCs of two category members with similar function groups and bracketting physical properties are used to define the upper and lower bound of the HLC range.  The resulting HLC range is 3400 – 4020 atm∙m³/mol at 22 °C.  HLC data for a more soluble category member, the predominant component of which is as an impurity of MTDID 50908, suggests a somewhat lower volatility for the more soluble, minor impurities (ca. 1030 atm∙m³/mol at 22 °C). This approach is considered reliable based on the validity of the experimental values provided. Based on the anticipated 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 with restrictions based on the similarity of chemical functional groups, molecular weights, water solubilities, and vapor pressures. The source data are from GLP-compliant studies which used scientifically acceptable methods, and they are considered reliable. This study is pertinent to the fate of MTDID 50908 and may be used for risk assessment, classification and labelling, and PBT analysis.