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Environmental fate & pathways

Phototransformation in air

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Description of key information

EPIWIN: DT50 = 0.72 days (calculated for 24 hours); Overall OH rate constant 22.26 E-12 cm³/molecules*sec 

Key value for chemical safety assessment

Half-life in air:
0.72 d
Degradation rate constant with OH radicals:
0 cm³ molecule-1 s-1

Additional information

According to Atkinson and Carter (1989), the rate constant for indirect photolysis is given as 2.13 E-20 cm3/(molecule*sec). For this photolysis type, 50% degradation has occurred after 6.5 days. As sensitiser O3 was used.

Referring to Atkinson (1989), the rate constant for indirect photolysis of monomethylamine with OH as sensitiser was found to be 2.2 E-11 cm3/(molecule*sec) at 299 K. When O3 is used as sensitiser for indirect photolyis (Atkinson, 1994) a constant k of (7.4 +/- 2.4) E-21 cm3/(molecule*sec) is reported at a temperature of 25 °C (298 K).

AOPWIN v1.92 (EPIWIN v3.20 software by US-EPA) was additionally used to calculate the phototransformation in air. As sensitiser OH is taken into account with a concentration of 1.5 E6 molecule/cm3. The overall OH rate constant is given as 22.26 E-12 cm3/molecule*sec.

50 % degradation occurs within 0.48 days (around 6 hours) taking a 12 hour - day into account while 0.72 days (around 17 hours) were calculated taking a 24 hour - day into account.