Registration Dossier

Environmental fate & pathways

Phototransformation in air

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

1,2-Dichloropropane undergoes reactions with hydroxyl radicals in the atmosphere.  The half-life of 1,2-dichloropropane due to this reaction is 34.9 days at 25 C with an OH radical concentration of 5 x 10e5 molecules/cm3 and 24 hour photoday.  1,2-Dichloropropane does not have any chromophores that absorb wavelengths > 290 nm, and thus, direct photolysis is not expected to be an important process in the atmosphere.  

Key value for chemical safety assessment

Half-life in air:
35 d

Additional information

The reaction of 1,2-dichloropropane with hydroxyl radicals has been measured experimentally in several studies. The measured rate constants are in excellent agreement with calculated values, and the value reported by Yuling et al was taken as representative (4.6 x 10e-13 cm3/molecule-sec). The calculated atmospheric half-life of 1,2-dichloropropane for the reaction with OH radicals is 34.9 days, based on an OH radical concentration of 5 x 10e5 molecules/cm3 and 24 hour photoday.  Since 1,2 -dichloropropane does not have any chromophores that absorb wavelengths > 290 nm, direct photolysis is not expected to be an important process in the atmosphere. 

 

Based on a review of the available literature for 1,2-dichloropropane and for its structural analogue,1,2-dichloroethane, the potential for 1,2-dichloropropane to contribute to global warming (GWP), to photochemical ozone creation (POCP), and to ozone depletion (ODP) have been assessed.  Photodegradation will account for removal of 1,2-dichloropropane from the atmosphere, based on a calculated half-life of 34.9 days at 25 C. The reaction with OH radicals proceeds via net hydrogen abstraction from C-H bonds.  In the atmosphere, the oxidation of the chloropropanes studied would be expected to lead to the formation of chlorinated carbonyls such as HC(O)Cl, CH3C(O)Cl, CH and3C(O)CH2Cl, CH2ClC(O)CH2Cl CH2ClCHClC(O)Cl.  These chlorinated carbonyl compounds may be lost by further reaction with OH radicals, by photolysis, or by wet deposition.  Based on the review, it can be concluded that the products of oxidation of 1,2-dichloropropane will not result in the introduction of chlorine into the stratosphere, and that potential contributions of 1,2-dichloropropane to global warming potential, photochemical ozone creation, and ozone depletion potential, are negligible.