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Environmental fate & pathways

Phototransformation in air

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Reference
Endpoint:
phototransformation in air
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
up to 2010
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR calculations, acceptable with restrictions
Justification for type of information:
QSAR prediction
Qualifier:
no guideline required
Guideline:
other: QSAR
Principles of method if other than guideline:
The estimation methods used by AOPWIN are based upon the structure-activity relationship (SAR) methods developed by Dr. Roger Atkinson and co-workers. AOPWIN incorporates updated fragment and reaction values as cited in Kwok and Atkinson (1995).
The AOPWIN version used in this study is v.193.
GLP compliance:
no
Remarks:
QSAR
Specific details on test material used for the study:
SMILES: C(C(C=CC12)C1)(C2C=C3)C3
CAS number: 77-73-6
Estimation method (if used):
Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. The author applied a least squares analysis of degradation rate constants to calculate a preferred value.
Light source:
not specified
Details on light source:
Not reported
Details on test conditions:
Not reported
Reference substance:
no
Remarks:
QSAR
Preliminary study:
Not reported
Test performance:
Not reported
Key result
% Degr.:
50
Sampling time:
1.077 h
Test condition:
OH Rate Constant = 119 E-12 cm^3/molecule-sec. Half-life = 0.090 Days (12 hour day; 1.5E6 OH/cm^3)
Remarks on result:
other: Result from QSAR
Key result
% Degr.:
50
Sampling time:
41.26 min
Test condition:
Ozone Rate Constant = 40.0 E-17 cm^3/molecule-sec. Half-life = 0.029 Days (at 7E11 mol/cm^3)
Remarks on result:
other: Result from QSAR
Transformation products:
not specified
Results with reference substance:
Not reported

Author reports a recommended rate constant of 119 E-12 cm3 molecule-1sec-1. Half life is calculated based on this rate constant and a hydroxyl radical concentration of 1.5 E+6 molecule.cm-3

Overall OH rate constant = 119.1993 E-12 cm3/molecule-sec

Half-life = 0.090 days (12-h day; 1.5E6 OH/cm3)

Half-life = 1.077 h

Overall ozone rate constant = 40.000000 E-17 cm3/molecule-sec

Half-life = 0.029 days (at 7 E+11 mol/cm3)

Half-life = 41.256 min

Validity criteria fulfilled:
not applicable
Remarks:
QSAR
Conclusions:
The overall OH rate constant was calculated to be 119.1993E-12 cm^3 molecule^-1 s^-1
Executive summary:

Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant based on all valid studies at the time of publication.

The prediction is considered to fall within the model domain.

Description of key information

Atmospheric photooxidation half-life of 1.077 hours (hydroxyl radicals) has been reported.

Key value for chemical safety assessment

Half-life in air:
1.077 h

Additional information

In Atkinson (1985), measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant based on all valid studies at the time of publication. The estimated half life is 1.077 hours based on an overall OH rate constant of 119.1993 E-12 cm³ molecule-1 s-1.