Sebacic acid

Phototransformation in air

Link to relevant study record(s)

Reference

Endpoint:

phototransformation in air

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Principles of method if other than guideline:

Calculation using SRC AOP v1.92

GLP compliance:

no

Estimation method (if used):

PHOTOCHEMICAL REACTION WITH OH RADICALS
- Concentration of OH radicals: 1500000 molecules/cm3
- Degradation rate constant: 34.5249 E-12 cm3/molecules*s
- Computer programme: SRC AOP v1.92
- Other: assuming a 12-hour day

DT50:

34.253 h

Test condition:

The substance is probably not within the applicability domain of the models.

AOP Program (v1.92) Results:

===========================

SMILES : O=C(O)CCCCCCCCC(=O)O

CHEM  : Decanedioic acid

MOL FOR: C10 H18 O4

MOL WT : 202.25

------------------- SUMMARY (AOP v1.92): HYDROXYL RADICALS (25 deg C) --------

Hydrogen Abstraction      = 10.2015 E-12 cm3/molecule-sec

Reaction with N, S and -OH =  1.0400 E-12 cm3/molecule-sec

Addition to Triple Bonds  =  0.0000 E-12 cm3/molecule-sec

Addition to Olefinic Bonds =  0.0000 E-12 cm3/molecule-sec

Addition to Aromatic Rings =  0.0000 E-12 cm3/molecule-sec

Addition to Fused Rings   =  0.0000 E-12 cm3/molecule-sec

 

OVERALL OH Rate Constant = 11.2415 E-12 cm3/molecule-sec

HALF-LIFE =    2.854 Days (12-hr day; 0.5E6 OH/cm3)

HALF-LIFE =   34.253 Hrs

Executive summary:

QPRF:AOPWIN

 

1.	Substance	See “Test material identity”
2.	General information
2.1	Date of QPRF	See “Data Source (Reference)”
2.2	QPRF author and contact details	See “Data Source (Reference)”
3.	Prediction
3.1	Endpoint (OECD Principle 1)	Endpoint	Phototransformation in air
		Dependent variable	Hydroxyl reaction rate constant (cm^3/molecule*sec)
3.2		Model or submodel name	AOPWIN
		Model version	1.92
		Reference to QMRF	QMRF: Estimation of Atmospheric Degradation Using AOPWIN v1.92 (EPI Suite v4.11): Hydroxyl Radical Reaction
		Predicted value (model result)	See “Results and discussion”
		Input for prediction	- Chemical structure via CAS number or SMILES
		Descriptor values	- Structure fragments
3.3	Algorithm (OECD Principle 2)	Domain (On-Line AOPWIN User’s Guide): As the complete training sets for AOPWIN's estimation methodology are not available, describing a precise estimation domain for this methodology is not possible. There is no information on the number of instances of fragments in the training dataset.
		If the substance is a member of one of the following chemical classes, the substance is probablywithinthe applicability domain of the model (based on information by other authors, e.g. Posthumus and Slooff, 2001): alkanes, haloalkanes, alkenes, haloalkenes, polyenes, terpenes, alkynes, aldehydes, ketones, alcohols, glycols, ethers, esters, epoxides, thiols, thioethers, aliphatic amines, hydrazines, nitrites, nitrates, nitriles, P-containing organics, aromatic compounds (alkylbenzenes, halobenzenes, phenols, PAHs, styrene, methoxybenzene, aniline, nitrobenzene, biphenyl, dibenzofurans, dibenzodioxins)		Not Fulfilled
		The substance isnotwithinthe applicability domain of the model if it is a perhalogenated alkanes.		Not Fulfilled
		Substance is a secondary, tertiary and heterocyclic amine. Estimated valueshighly uncertain.		Not Fulfilled
3.4	The uncertainty of the prediction (OECD principle 4)	- n = 667 - correlation coefficient r^2= 0.963 - standard deviation = 0.218 - absolute mean error = 0.127 - 90% of the estimated rate constants within a factor of two of the experimental data - 95% of the estimated rate constants within a factor of three of the experimental data
3.5	The chemical mechanisms according to the model underpinning the predicted result (OECD principle 5)	Reaction rate constants for hydroxyl radicals are the summation of the following mechanisms: (1) Hydrogen abstraction (2) Reaction with specific nitrogen and sulphur fragments and reaction with hydroxyl (OH) fragments such as alcohols and phenols (3) Addition to triple bonds (4) Addition to olefinic bonds (5) Addition to aromatic rings (6) Addition to fused rings The model works according to the group contribution method which uses fragments and the corresponding reaction values to estimate the reaction rate constant of a given substance.

 

References

- R Posthumus and W Slooff (2001). Implementation of QSARs in ecotoxicological risk assessments. RIVM report 601516 003. Online: http://rivm.openrepository.com/rivm/bitstream/10029/9559/1/601516003.pdf

- US EPA (2012). On-Line AOPWIN User’s Guide.

 

Description of key information

After evaporation or exposure to the air, the product will be slowly degraded by photochemical processes.

Key value for chemical safety assessment

Half-life in air:

34.25 h

Additional information

In Article 13 of Regulation (EC) No 1907/2006, it is laid down that information on intrinsic properties of substances may be generated by means other than tests, provided that the conditions set out in Annex XI (of the same Regulation) are met. Furthermore according to Article 25 of the same Regulation testing on vertebrate animals shall be undertaken only as a last resort.

 According to Annex XI of Regulation (EC) No 1907/2006 (Q)SAR results can be used if (1) the scientific validity of the (Q)SAR model has been established, (2) the substance falls within the applicability domain of the (Q)SAR model, (3) the results are adequate for the purpose of classification and labeling and/or risk assessment and (4) adequate and reliable documentation of the applied method is provided.

 For the assessment of CAS 111-20-6 (Q)SAR results were used for phototransformation in air.The criteria listed in Annex XI of Regulation (EC) No 1907/2006 are considered to be adequately fulfilled and therefore the endpoint(s) sufficiently covered and suitable for risk assessment.

 Therefore, further experimental studies on phototransformation in air are not provided.

Based on a calculation according to AOPWIN v1.92, sebacic acid is indirectly photodegraded by reaction with hydroxyl radicals in the atmosphere with a half-life (t1/2) of about 34 hours taking into account a 24-h day and a mean OH radical concentration of 0.5E06 radicals per cm³ [BASF SE, 2010].