1,2,4-trimethylbenzene

Phototransformation in air

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

Test material information

Constituent 1

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.