Registration Dossier

Administrative data

Endpoint:
phototransformation in air
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
06-Dec-2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Structurally, the C4-acrylate contains moieties that have experimental group rate constants utilized by the software (AOPWIN) to calculate the OH radical reaction rate constants. Experimental results show that reaction of hydroxyl radicals with sulfonamide groups is a minor channel for perfluoroalkyl sulfonamide phototransformation (D'eon, et al.). Additionally, comparative evaluation with the experimental value of the analogous compounds acrylate esters and fluorinated alkyls (also in the training set) indicates the conservative nature of this estimate. Thus, it is within the domain. D'eon, J.C.; Hurley, H.D.; Wallington, T.J.; Mabury, S.A. "Atmospheric chemistry of N-methyl perfluorobutane sulfonamidoethanol, C4F9SO2N(CH3)CH2CH2OH: kinetics and mechanism of reaction with OH." Environ. Sci. Technol. 2006, 40, 1862-1868.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6

Data source

Reference
Reference Type:
other company data
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: QSAR results
Deviations:
no
GLP compliance:
no
Remarks:
AOPWIN v1.92 as implemented through EPI Suite v4.10

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
CAS No. 67584-55-8
SMILES: FC(F)(C(F)(F)C(F)(F)C(F)(F)F)S(=O)(=O)N(C)CCOC(=O)C=C

Study design

Estimation method (if used):
EPI Suite module AOPWIN (v1.92) utilizes experimentally determined group rate constants to estimate the overall OH radical reaction rate constant for a chemical. EPISuite is a valid QSAR and this substance is within the applicability domain since there are analogous substances in the training set.
Light source:
other: Not Applicable (QSAR)
Details on light source:
Not Applicable (QSAR)
Details on test conditions:
QSAR

Results and discussion

Dissipation half-life of parent compound
DT50:
16.7 h
Test condition:
QSAR simulation
Degradation rate constant
Reaction with:
OH radicals
Rate constant:
0 cm³ molecule-1 d-1

Any other information on results incl. tables

Validity of Model (OECD 5 principles):

1) Defined endpoint: Photodegradation rate

2) Unambiguous algorithm: The predicted value of the rate constant for reaction with hydroxyl radicals is calculated through the following equation:

overall OH rate const = ∑F(x)k{group}

where F(x) is the substituent scale factor and k{group} is the hydroxyl radical reaction rate constant for each individual chemical group in the test species.

3) Applicability domain: the software's training set contains several alkyl ester acrylate and fluorinated alkyl compounds which are structurally related to the test substance. The sulfonamide is not represented in the training set and does not contribute to the calculated rate constant. Experimental results show that reaction of hydroxyl radicals with sulfonamide groups is a minor channel for perfluoroalkyl sulfonamide phototransformation (D'eon, et al.). This is not an exhaustive list of all chemical species in the reference data, merely those which may be grouped with the test compound. The test substance is therefore within the applicability domain of the model.

4) Statistical characterization: Statistical variation of 30 pairs of experimental and predicted photodegradation rates for alkyl esters, alkyl acrylates, and fluorinated alkanes and indicates that there is a 0.978 correlation coefficient (r-squared), a standard deviation of 0.178 and an absolute mean error of 0.123.

5) Mechanistic interpretation: The primary mechanism of photolysis is through indirect photodegradation by reaction with hydroxyl radicals which are produced during the daylight hours.

Please see attached QMRF and QPRF for justification of model and applicability.

D'eon, J.C.; Hurley, H.D.; Wallington, T.J.; Mabury, S.A. "Atmospheric chemistry of N-methyl perfluorobutane sulfonamidoethanol, C4F9SO2N(CH3)CH2CH2OH: kinetics and mechanism of reaction with OH." Environ. Sci. Technol. 2006, 40, 1862-1868.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Remarks:
This model conforms with the 5 principles set forth by OECD for validation of QSAR models.
Conclusions:
The half-life of C4-acrylate, based on hydroxyl radical concentrations in the atmosphere of 5.0E5 OH radicals / cm3, is estimated to be 16.7 hours. This indicates that the test material is not expected to be persistent in the atmosphere and long range transport is not expected.
Executive summary:

Photolysis of C4-acrylate was estimated utilizing the AOPWIN v1.92 module of EPISuite v4.10.  Structurally, C4-acrylate contains moieties that are part of the training set of the software (with the exception of the sulfonamide) and is thus, within the predictive domain of the software. Hydroxyl radical reactions with sulfonamide groups is not expected to be a major pathway based on experimental results for a related compound. The effect would be to further reduce half-life of C4-acrylate.  

The half-life/DT50 (50% decline times) of the test substance, using hydroxyl radical concentrations in the atmosphere of 5.0E5 OH radicals / cm3, was predicted to be 16.7 hours. This indicates that the test material is not expected to be persistent in the atmosphere and long range transport is not expected.  

This study is classified as an acceptable QSAR and satisfies the requirements for photolysis study. It is pertinent to the fate of C4-acrylate and is suitable for use in Risk Assessment, Classification & Labeling, and PBT Analysis.