2,4,6-trimethylphenol

Phototransformation in air

Administrative data

Endpoint:

phototransformation in air

Type of information:

(Q)SAR

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Study period:

September 2016

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a (Q)SAR model, with limited documentation / justification, but validity of model and reliability of prediction considered adequate based on a generally acknowledged source

Justification for type of information:

1. SOFTWARE
AOPWIN

2. MODEL (incl. version number)
v.1.92a

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
Oc(c(cc(c1)C)C)c1C

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
- Defined endpoint: the rate constant for the atmospheric, gas-phase reaction between photochemically produced hydroxyl radicals and organic chemicals.
The rate constant for the gas-phase reaction between ozone and olefinic/acetylenic compounds.
The rate constants estimated by the program are then used to calculate atmospheric half-lives for organic compounds based upon average atmospheric concentrations of hydroxyl radicals and ozone.
- Unambiguous algorithm: please refer to the attached supporting document "Estimation Methodology_AOPWIN "
- Defined domain of applicability: please refer to the attached supporting document "Accuracy & Domain_AOPWIN"
- Appropriate measures of goodness-of-fit and robustness and predictivity: please refer to the attached supporting document "Accuracy & Domain_AOPWIN"

5. APPLICABILITY DOMAIN
- Descriptor domain: please refer to the attached supporting document "Accuracy & Domain_AOPWIN"
- Structural and mechanistic domains: - Structural and mechanistic domains: the substance falls in the structural domain of this model.

6. ADEQUACY OF THE RESULT
The result is considered adequate for hazard/risk assessment since a scientifically valid (Q)SAR model has been used, the substance falls within the applicability domain of the (Q)SAR model and the prediction fits for the regulatory purpose.

For more details, please refer to the On-Line AOPWIN™ User's Guide from EPI Suite v.4.11 available by EPI Suite v.4.11 download:
https://www.epa.gov/tsca-screening-tools/epi-suitetm-estimation-program-interface

Data source

Reference

Reference Type:

other: Summary report of AOP v1.92 module estimation (Episuite v.4.11)

Title:

Unnamed

Year:

2016

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: REACH Guidance on QSARs R.6

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-trimethylphenol

EC Number:

208-419-2

EC Name:

2,4,6-trimethylphenol

Cas Number:

527-60-6

Molecular formula:

C9H12O

IUPAC Name:

2,4,6-trimethylphenol

Study design

Reference substance:

no

Results and discussion

Dissipation half-life of parent compound

Key result

DT50:

ca. 0.438 d

Test condition:

12-hr day; 1.5E6 OH/cm3

Remarks on result:

other: in silico prediction

Degradation rate constant

Key result

Reaction with:

OH radicals

Rate constant:

0 cm³ molecule-1 s-1

Remarks on result:

other: in silico prediction

Transformation products:

not specified

Any other information on results incl. tables

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

Hydrogen Abstraction      =  0.4080 E-12 cm3/molecule-sec

Reaction with N, S and -OH =  0.1400 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 = 23.8825 E-12 cm3/molecule-sec

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

 

OVERALL OH Rate Constant = 24.4305 E-12 cm3/molecule-sec

HALF-LIFE =    0.438 Days (12-hr day; 1.5E6 OH/cm3)

HALF-LIFE =    5.254 Hrs

........................ ** Designates Estimation(s) Using ASSUMED Value(s)

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

 

****** NO OZONE REACTION ESTIMATION ******

(ONLY Olefins and Acetylenes are Estimated)

 

NOTE: Reaction with Nitrate Radicals May Be Important!

 

Experimental Database: NO Structure Matches

Fraction sorbed to airborne particulates (phi):

1.55E-005 (Junge-Pankow, Mackay avg)

9.91E-005 (Koa method)

Note: the sorbed fraction may be resistant to atmospheric oxidation

n

Applicant's summary and conclusion

Validity criteria fulfilled:

not applicable

Conclusions:

AOP v1.92 module estimation (Episuite v.4.11):
OVERALL OH Rate Constant = 24.4305 E-12 cm3/molecule-sec
HALF-LIFE =    0.438 Days (12-hr day; 1.5E6 OH/cm3)
HALF-LIFE =    5.254 Hrs