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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data are taken from published, peer-reviewed journal articles. The data are presented in review articles and no information is available on the data sources.

Data source

Reference
Reference Type:
review article or handbook
Title:
Gas-phase tropospheric chemistry of organic compounds: a review
Author:
Atkinson R
Year:
1990
Bibliographic source:
Atmospheric Environment. 24A (1): 1-41

Materials and methods

Principles of method if other than guideline:
Guideline not stated. Kinetic data taken from Atkinson R (1990). Kinetics and mechanisms of the gas-phase reactions of the hydroxyl radical with organic compounds. Journal of Physical and Chemical Reference Data.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
1,2,4-trimethylbenzene
EC Number:
202-436-9
EC Name:
1,2,4-trimethylbenzene
Cas Number:
95-63-6
Molecular formula:
C9H12
IUPAC Name:
1,2,4-trimethylbenzene
Details on test material:
No data reported
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Study design

Estimation method (if used):
The half-life of 1,2,4-trimethylbenzene was calculated using the formula: half-life = ln2/(rate constant*OH concentration*time) where the OH concentration is 5E+05 and the time is 86400 seconds.
Light source:
not specified
Details on light source:
No data reported
Details on test conditions:
Kinetic data taken from Atkinson R (1990). Kinetics and mechanisms of the gas-phase reactions of the hydroxyl radical with organic compounds. Journal of Physical and Chemical Reference Data.
Reference substance:
not specified

Results and discussion

Preliminary study:
The kinetic rate constant for the reaction of 1,2,4-trimethylbenzene with OH radicals is measured to be 32.5 E+12 cm3/mol/s.
Test performance:
The atmospheric half-life of 1,2,4-trimethylbenzene is calculated to be approximately 12 hours.
% Degradation
% Degr.:
50
Sampling time:
12 h
Degradation rate constant
Reaction with:
OH radicals
Rate constant:
0 m³ molecule-1 s-1
Transformation products:
not specified
Results with reference substance:
Not applicable

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
The kinetic rate constant for the reaction of 1,2,4-trimethylbenzene with OH radicals is measured to be 32.5-40 E+12 cm3/mol/s, indicating that the atmospheric half-life would be 12 hours.
Executive summary:

Atkinson (1990) is a review article, with no data reported on the test methods or conditions of the original data source. Never-the-less, the data are taken from a published, peer-reviewed journal article and are considered to be suitable as supporting data for this endpoint. The measured results provide a rate constant of the reaction of 1,2,4 -trimethylbenzene with OH radicals of 32.5 E+12 cm3/mol/s. The results indicate that the substance would have an atmospheric half-life of approximately 12 hours and therefore would not be persistent in the atmospheric compartment.