Registration Dossier

Environmental fate & pathways

Phototransformation in air

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Data on the kinetic rate constant for the reaction of members of the category with OH radicals were not available for any of the streams within this category. However, as the category consists of mainly C4 hydrocarbons, data were read-across from hydrocarbon C4 substances. Atkinson (1985) 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 for this endpoint. The measured results provide a rate constant of the reaction of OH radicals with three read-across hydrocarbon C4 substances (106-98 -9: 3.14 E-11 cm3/mol/s, 115-11-7: 5.14 E-11 cm3/mol/s, 106-97-8: 2.53 E-12 cm3/mol/s). The results indicate that the category would have an atmospheric half-life of approximately 0.5 days (106-98-9), 7.5 hours (115-11-7) and 6.3 days (106-97-8) and therefore would not be persistent in the atmospheric compartment.

The kinetic rate constant for the reaction of members of the category with OH radicals is therefore considered to be 3.14E-11 to 2.53E-12 cm3/mol/s, indicating that the atmospheric half-life would be in the range 7.5 hours to 6.3 days.

The mean of the atmospheric half-life values for the category is 2.4 days and this has been used to complete the 'key value for chemical safety assessment'.

Key value for chemical safety assessment

Half-life in air:
2.4 d

Additional information