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Diss Factsheets

Environmental fate & pathways

Phototransformation in air

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Reference
Endpoint:
phototransformation in air
Type of information:
calculation (if not (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 and falling into its applicability domain, with adequate and reliable documentation / justification
Principles of method if other than guideline:
calculated using EpiSuite 4.10 (US EPA, 2008)
GLP compliance:
no
Details on test conditions:
Sensitiser (for indirect photolysis): OH
Key result
% Degr.:
50
Sampling time:
4.15 h
Test condition:
estimated half-life, OH reaction
Key result
Reaction with:
OH radicals
Rate constant:
ca. 0 cm³ molecule-1 s-1
Transformation products:
not specified

AOP Program (v1.92) Results:

SMILES : O=C(C(C)C)OCCCCCCCCCCCCCCCCCCCCCC

CHEM   : 2-Propenoic acid, 2-methyl-, docosyl ester

MOL FOR: C26 H52 O2

MOL WT : 396.70

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

Hydrogen Abstraction       =  30.9381 E-12 cm3/molecule-sec

Reaction with N, S and -OH =   0.0000 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 =  30.9381 E-12 cm3/molecule-sec

  HALF-LIFE =     0.346 Days (12-hr day; 1.5E6 OH/cm3)

  HALF-LIFE =     4.149 Hrs

SUMMARY (AOP v1.91): OZONE REACTION (25 deg C)

NO OZONE REACTION ESTIMATION (ONLY Olefins and Acetylenes are Estimated) .

Experimental Database:  NO Structure Matches

Fraction sorbed to airborne particulates (phi):

 0.355 (Junge-Pankow, Mackay avg)

0.611 (Koa method)

Note: the sorbed fraction may be resistant to atmospheric oxidation

Validity criteria fulfilled:
not applicable
Conclusions:
The Phototransformation in air of docosyl methacrylate has been modelled using EPIWEB version 4.1, AopWin v1.92. The Hydroxyl radicals reaction rate constant has been estimated to be 3.09E-11 cm³/molecule/s, the half-life was calculated to 4.15 hours or 0.346 days (12 hr day, at 1.5E6 OH/cm³).
Executive summary:

The Phototransformation in air of docosyl methacrylate has been modelled using EPIWEB version 4.1, AopWin v1.92. The Hydroxyl radicals reaction rate constant has been estimated to be 3.09E-11 cm³/molecule/s, the half-life was calculated to 4.15 hours or 0.346 days (12 hr day, at 1.5E6 OH/cm³).

Description of key information

After evaporation or exposure to the air, the substance will be rapidly degraded by photochemical processes.

Key value for chemical safety assessment

Half-life in air:
4.15 h
Degradation rate constant with OH radicals:
0 cm³ molecule-1 s-1

Additional information

QSAR-disclaimer

 

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 docosyl methacrylate (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 constant are not provided.