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Environmental fate & pathways

Phototransformation in air

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Description of key information

Calculation with AOPWIN v1.92 (EPIWIN software by US-EPA), overall gas-phase reaction constant: 38.6737E-12 cm³/molecules-sec, with an half-life of 3.30 hours by assuming a 12 hr day with an OH rate constant of 1.5E6 OH/cm³ and 25 °C.

Key value for chemical safety assessment

Half-life in air:
3.3 h

Additional information

The phototransformation in air of the test substance was determined by the computer program AOPWIN v1.92 (EPIWIN software) by US-EPA. This tool estimates the gas-phase reaction rate for the reaction between the most prevalent atmospheric oxidant (hydroxyl radicals) and a substance. For olefins and acetylenes the gas-phase ozone radical reaction rates are estimated as well. Additional information is given by the program if nitrate radical reaction will be important. The assumed average hydroxyl radical and ozone concentration are automatically used to calculate the atmospheric half-live for the chemical of interest.

For the test substance an overall OH rate constant (gas-phase reaction constant) of 38.6737E-12 cm3/molecules-sec and a half-life of 0.277 days (3.3 hours) was calculated, assuming a 12- hr day with an OH rate constant of 1.5 E6 OH/cm³. No ozone reaction as well as no nitrate radical reaction is estimated for the compound.