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Environmental fate & pathways

Phototransformation in air

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Description of key information

The phototransformation of AAPB consisting of C8-, C10-, C12-, C14-, C16-, and C18-fatty acids was calculated using EPIWIN v3.11, AOPWIN v1.91. The calculation yielded half-lives ranging from 6.8 h (C18 derivate) to 9 h (C8 derivate).

Key value for chemical safety assessment

Half-life in air:
9 h

Additional information

The phototransformation of AAPB consisting of C8-, C10-, C12- , C14- , C16-, and C18-fatty acids was calculated using EPIWIN v3.11, AOPWIN v1.91. Based on a OH radical concentration of 500000 molecules/cm³ (24 h-day, average hydroxyl concentration) and the estimated atmospheric reaction rate constants (C8: 42.769 x 10E-12 cm³/molecule x s; C10: 45.595 x 10E-12 cm³/molecule x s; C12: 48.420 x 10E-12 cm³/molecule x s; C14: 51.247 x 10E-12 cm³/molecule x s; C16: 54.073 x 10E-12 cm³/molecule x s, and C18: 56.899 x 10E-12 cm³/molecule x s) half-lives ranging from 6.8 h (C18 derivate) to 9 h (C8 derivate) were calculated. The results indicate theoretically a rapid photodegradation (t1/2<10 h) of the components (C8 -C18 derivates) of AAPB. Due to the ionic character of the compound and the low vapor pressure, however, the occurrence of gaseous AAPB in air is expected to be negligible and therefore this degradation pathway is only of minor importance.