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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Environmental fate & pathways

Phototransformation in air

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Administrative data

phototransformation in air
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
Up to 1985
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non guideline study. Calculated data, published in peer review paper and was calculated in accordance with the TGD.

Data source

Reference Type:
Kinetics and mechanisms of gas-phase reactions with the hydroxyl radical with organic compounds under atmospheric conditions
Atkinson, C
Bibliographic source:
Chemistry Review. 85, 61-201.

Materials and methods

Principles of method if other than guideline:
The author used data from other investigators. This data was generated using two methods: absolute and relative constant techniques. The author then applied a least squares analysis of degradation rate constants for organic chemicals by hydroxyl radicals developed by other investigators. This calculation was in accordance with the TGD
GLP compliance:
not specified
Not reported

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
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):
No data reported

Study design

Estimation method (if used):
Endpoint was calculated based on a rate constant of 3.5 E -12 and-OH radical concentration of 5 E5 molecules/cm3
Details on light source:
No data reported
Details on test conditions:
No data reported

Results and discussion

Preliminary study:
No data reported
Test performance:
No data reported
Dissipation half-life of parent compound
2.3 d
Results with reference substance:
No data reported

Any other information on results incl. tables

Based on a calculated rate constant of 7.38E-12 cm3 molecule-1sec-1, and a hydroxyl radical concentration of 5E5

Applicant's summary and conclusion

The dissipation half-life of 2-methylbutane was calculated as 2.3 days
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 for 2 -methylbutane based on all valid studies at the time of publication. The half life of 2 -methylbutane is 2.3 days.