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Environmental fate & pathways

Phototransformation in air

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Description of key information

After evaporation or emission to the air, the product will be slowly degraded by photochemical processes.

Key value for chemical safety assessment

Half-life in air:
2.5 d

Additional information

Measured rate constants of cyclohexanone are similar to calculated ones. Atkinson (1989) reports a measured rate constant for indirect photodegradation of 6.39 *10E-12 cm3/molecule*sec, resulting in a half time for OH-degradation of 2.5 days. This is supported by a calculation using SRC AOP v1.92, revealing a rate constant of 1.2 E-11 cm molecule-1 sec-1 and resulting in a half time of 2.7 days for indirect photodegradation. For both calculations a 24 -hour day as well as a sensitizer-concentration (OH-radicals) of 500000 molecules/cm³ were assumed.