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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Accepted calculation method; substance presumably within applicability domain of the model

Data source

Referenceopen allclose all

Reference Type:
other: EPIWin calculation
Title:
Unnamed
Year:
2014
Report date:
2015
Reference Type:
other: Estimation software
Title:
Estimation Programs Interface Suite for Microsoft Windows, v4.11
Author:
US-EPA
Year:
2017
Bibliographic source:
United States Environmental Protection Agency, Washington, DC, USA

Materials and methods

Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Calculation using AOPWIN v1.92
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
2-methylpyridine
EC Number:
203-643-7
EC Name:
2-methylpyridine
Cas Number:
109-06-8
Molecular formula:
C6H7N
IUPAC Name:
2-methylpyridine
Constituent 2
Details on test material:
- Name of test material (from EPISuite CAS inventory): 2-Methylpyridine

Study design

Estimation method (if used):
PHOTOCHEMICAL REACTION WITH OH RADICALS:
- Computer programme: SRC AopWin v1.92;
- Concentration of OH radicals: 5E+05 molecules/cm³ (northern hemisphere);
- Time frame: 24-hour day;
- Degradation rate constant: 1.1019E-12 cm³/molecule·s;
- Temperature for which rate constant was calculated: 25°C.

Results and discussion

Dissipation half-life of parent compound
DT50:
14.56 d
Test condition:
half-life calculated for the following conditions: sensitizer for indirect photolysis: OH; 0.5 E06 OH/cm³, 24h day; substance presumably within applicability domain

Any other information on results incl. tables

SUMMARY (AOP v1.92):

HYDROXYL RADICALS (25 °C):

Hydrogen Abstraction

 0.1360 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

 0.9659 E-12 cm3/molecule-sec

Addition to Fused Rings

 0.0000 E-12 cm3/molecule-sec

Overall OH Rate Constant

 1.1019 E-12 cm3/molecule-sec

Half-life

 14.560 days

Applicant's summary and conclusion

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 (cm3/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 probably within the 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)

Fulfilled

The substance is not within the applicability domain of the model if it is a perhalogenated alkane.

Not Fulfilled

Substance is a secondary, tertiary and heterocyclic amine. Estimated values highly uncertain.

Not Fulfilled

3.4

The uncertainty of the prediction
(OECD principle 4)

- n = 667

- correlation coefficient r2= 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.