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Environmental fate & pathways

Hydrolysis

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Reference
Endpoint:
hydrolysis
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study conducted according to internationally accepted guideline (OECD 111) and well documented.
Qualifier:
according to
Guideline:
OECD Guideline 111 (Hydrolysis as a Function of pH)
GLP compliance:
not specified
Preliminary study:
Not performed
Transformation products:
no
pH:
7
Temp.:
20 °C
DT50:
98 000 h
pH:
7
Temp.:
50 °C
DT50:
737 h
pH:
7
Temp.:
65 °C
DT50:
82.5 h
pH:
9
Temp.:
28.6 °C
DT50:
70.8 h
pH:
9
Temp.:
50 °C
DT50:
31.5 h
Details on results:
Hydrolysis was determined at pH 4, 7 and 9. At 50 °C the half-lives (t 1/2) at pH 7 and 9 were determined in range finding tests to be respectively 737 and 31.5 hours. The compound appeared to be stable at pH 4 at this temperature. More extensive tests at pH 7 for temperatures of 80 and 65 °C gave t 1/2 values of 8.8 and 82.5 hours respectively, and extrapolations (Arrhenius relation) provided an estimate for t 1/2 at 25 °C and pH 7 of around 98000 hours (4000 days). A separate test at pH 9 and 28.6 °C gave t 1/2 = 71 hours, and so it can be concluded that hydrolysis is very slow under ambient temperature conditions at pH 7, but considerably faster under mild alkaline conditions.

Description of key information

Hydrolysis is not expected: Half-life at pH 7 and at 25 °C = 4000 days (OECD 111) 

Key value for chemical safety assessment

Half-life for hydrolysis:
4 000 d
at the temperature of:
25 °C

Additional information

The hydrolysis potential (half- life) of the test substance was determined according to OECD 111 (NICNAS, 1999). Hydrolysis was determined at pH 4, 7 and 9. At 50 °C the half- lives (t 1/2) at pH 7 and 9 were determined in range finding tests to be respectively 737 and 31.5 hours. The compound appeared to be stable at pH 4 at this temperature. More extensive tests at pH 7 for temperatures of 80 and 65 °C gave t 1/2 values of 8.8 and 82.5 hours respectively, and extrapolations (Arrhenius relation) provided an estimate for t 1/2 at 25 °C and pH 7 of around 98000 hours (4000 days). A separate test at pH 9 and 28.6 °C gave t 1/2 = 71 hours, and so it can be concluded that hydrolysis is very slow under ambient temperature conditions at pH 7, but considerably faster under mild alkaline conditions.