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Environmental fate & pathways

Phototransformation in air

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Description of key information

See below.

Key value for chemical safety assessment

Half-life in air:
1.3 h

Additional information

The photodegradation of OTNE was studied by Aschmann et al. (2001) under laboratory conditions using blacklamps for irradiation (l > 300 nm) at 25 °C and 740 mm Hg (0.986 bar) total pressure of purified air at ~5% relative humidity. Rate constants were measured for the gas phase reactions of OH radicals, NO3 radicals and ozone. The measured rate constants (in cm3molecule-1s-1) are 9.85 ± 0.88.10-11 (OH radicals), 17.1 ± 1.9.10-12(NO3 radicals) and 2.1 ± 0.5.10-18(O3).

Combined with estimated ambient atmospheric concentrations of OH radicals, an atmospheric lifetime of 1.4 hours is calculated (t½ = 1 h) based on a 12-hour daylight average atmospheric concentration of 2.0.106 molecule cm-3, assuming a daylight period of 12 h and 1.5.106 OH cm-3, t½ based on the empirical rate is 1.9 h.

For reaction with NO3 radicals and O3, the atmospheric lifetime is 2 minutes (t½ = 1.4 min) and 8 days (t½ = 5.5 days) respectively. These data indicate that the atmospheric lifetime of OTNE is sufficiently short that it will not undergo long-range transport to any significant extent

The substance does not have an ozone depletion potential because it does not contain halogens and does not have the potential to reach the stratosphere.