Registration Dossier
Registration Dossier
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EC number: 200-838-9 | CAS number: 75-09-2
Phototransformation in air
Administrative data
Link to relevant study record(s)
Description of key information
Dichloromethane undergoes reactions with hydroxyl radicals in the atmosphere. The half life of dichloromethane due to this reaction, based on a 12-hr day with a OH radical concentration of 1.5E6 OH/cm3 is 107 days.
Key value for chemical safety assessment
- Half-life in air:
- 107 d
Additional information
Since dichloromethane does not absorb light above 290 nm, it will not degrade by direct photolysis in the troposphere. In the troposphere dichloromethane is photochemically oxidized by hydroxyl radicals abstracting H atoms. The calculated half life of dichloromethane due to this reaction is 107 days using an OH radical concentration of 1.5E6 OH/cm3 (AOPWIN, 2000), the corresponding OH-rate constant is 1.0 +/- 0.1 E-13 cm3/molecule.sec at 298 K, based on preferred values from IUPAC.
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