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Physical & Chemical properties

Partition coefficient

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Endpoint:
partition coefficient
Data waiving:
study technically not feasible
Justification for data waiving:
other:
Justification for type of information:
JUSTIFICATION FOR DATA WAIVING
In accordance with Column 2 of REACH Annex VII, the partition coefficient n-octanol/water study was not performed because the substance is hydrolytically unstable in water (half-life time < 4 minutes). The shake flask method, the HPLC method and the estimation method are not applicable. Calculation of the partition coefficient using the Rekker calculation method is not applicable either since silicium containing fragments are not included in this method.
Reason / purpose:
data waiving: supporting information
Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions
Remarks:
Conducted with the hydrolysis product MPKO.
Qualifier:
according to
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Deviations:
not specified
Qualifier:
according to
Guideline:
EU Method A.8 (Partition Coefficient)
Deviations:
not specified
GLP compliance:
yes (incl. certificate)
Type of method:
HPLC method
Partition coefficient type:
octanol-water
Analytical method:
high-performance liquid chromatography
Key result
Type:
log Pow
Partition coefficient:
ca. 1.25
Temp.:
22 °C
pH:
ca. 7

Neutral pH

Neutral pH

Pow

log Pow

Major component peak 1

1.6 x 10

1.2

Major component peak 2

2.1 x 10

1.3

Conclusions:
The partition coefficient of MPKO was determined to be 1.25 at 22°C (pH 7).
Executive summary:

The log Pow of MPKO was determined by means of HPLC at neutral pH in accordance with OECD Guideline 107 and EU Method A.8. The following values were determined: Major component peak 1 has a log Pow of 1.2 (Pow = 1.6 x 10). Major component peak 2 has a log Pow of 1.6 (Pow = 2.1 x 10)

Description of key information

The test substance hydrolyses quickly (half life time < 4 minutes) therefore the partition coefficient cannot be determined. The partition coefficient of MPKO, the hydrolysis product of OS2600, was determined to be 1.25 at 22°C (pH 7)

Key value for chemical safety assessment

Log Kow (Log Pow):
1.25
at the temperature of:
22 °C

Additional information

Data waiving (study technically not feasible): In accordance with Column 2 of REACH Annex VII, the partition coefficient n-octanol/water study was not performed because the substance is hydrolytically unstable in water (half-life time < 4 minutes). The shake flask method, the HPLC method and the estimation method are not applicable. Calculation of the partition coefficient using the Rekker calculation method is not applicable either since silicium containing fragments are not included in this method.

Supporting study: The log Pow of the analogue substance MPKO was determined by means of HPLC at neutral pH in accordance with OECD Guideline 107 and EU Method A.8. The partition coefficient of MPKO was determined to be 1.25 at 22°C (pH 7).