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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

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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