Registration Dossier

Environmental fate & pathways

Phototransformation in air

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Administrative data

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Description of key information

No data is available for 2,2,3-trimethylbutane. However, data is available for Isoheptane and is being read across to using the category approach explained in the category justification document attached to Section 13 of the dossier.

Isoheptane has the potential to volatilize to air, based on a relatively high vapor pressure, where it is subject to atmospheric oxidation. In air, Normal-Heptane can react with photosensitized oxygen in the form of hydroxyl radicals (OH-).

Estimation with the APOWIN model (HSPA Consortium 2010) resulted in a test substance half-life, as mediated by hydroxyl radical (OH-) attack is calculated as 1.56 days based on a 12-hour day (the 12-hour day half-life value normalizes degradation to a standard day light period during which hydroxyl radicals needed for degradation are generated). The half-life was calculated based on an OH- reaction rate constant of 6.8630 E-12 cm3/molecule-sec and an OH-concentration of 1.5E6 OH/cm3.

Key value for chemical safety assessment

Half-life in air:
1.56 d
Degradation rate constant with OH radicals:
0 cm³ molecule-1 s-1

Additional information