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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2002-2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Remarks:
Study was carried out according to generally valid and internationally accepted testing guidelines and under GLP.
Qualifier:
according to guideline
Guideline:
OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method)
Qualifier:
according to guideline
Guideline:
EU Method A.8 (Partition Coefficient)
Principles of method if other than guideline:
An estimate of the maximum solubility of the test item in n-octanol was performed by mixing the test item with different amounts of n-octanol for approximately 1 hour at room temperature away from light. After shaking a visual assessment of solubility was made. The solubility in water of the test item was previously determined (7775-09-9, Water solubility, Groult, 2004, RS-28186 PSE).
GLP compliance:
yes
Type of method:
estimation method (solubility ratio)
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
< -2.9
Temp.:
20 °C
pH:
0
Type:
Pow
Partition coefficient:
< 0.001
Temp.:
20 °C
pH:
0
The solutions of the test item in n-octanol were all saturated. The preliminary test indicated that the test item was weakly soluble in n-octanol
(< 1 g/L).
Estimation based on the individual solubilities of the test item in n-octanol and water:
Pow = Coctanol / Cwater: < (1/717) this is < 0.001and log Pow < -2.9The HPLC method or shake-flask method were not applicable (log Pow < -2.9) at 20 degrees Celcius.Consequently, the test was considered to be complete.0 = No data on pH.
Conclusions:
Pow < 0.001 and log Pow < -2.9
Endpoint:
partition coefficient
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
sodium chlorate (CAS: 7775-09-9)
Adequacy of study:
key study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
[further information is included as attachment to Iuclid section 13]

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The analogue approach is based on the chemical structure of potassium chlorate (KClO3) and sodium chlorate (NaClO3) and the position of K (potassium) and Na (sodium) in the Mendeleiv table (K is just below Na in the same column) allowing to anticipate a close behaviour for both substances, especially regarding the weak solubility of both substances in n-octanol (< 1 g/L).

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Refer to the Test material section of the source and target records.

3. ANALOGUE APPROACH JUSTIFICATION
See attached document in Iuclid section 13

4. DATA MATRIX
See attached document in Iuclid section 13
Reason / purpose for cross-reference:
read-across: supporting information
Reason / purpose for cross-reference:
read-across source
Key result
Type:
log Pow
Partition coefficient:
< -2
Temp.:
20 °C
Remarks on result:
other: pH not reported
Executive summary:

This endpoint can be assessed using a dedicated guideline study. The log Kow of Sodium chlorate (CAS 7775 -09 -9) was evaluated in a GLP and reliable experimental test showing a Log Kow <-2.9. The water solubility of potassium chlorate was measured to be 10 times less than for sodium chlorate but is still highly soluble. It is therefore expected that the partition coefficient would be approximately 10 times less than that of the sodium salt. For this reason a log Kow of -2 has been used in the CSR.

Description of key information

Key value for chemical safety assessment

Log Kow (Log Pow):
-2
at the temperature of:
20 °C

Additional information

This endpoint can be assessed using a dedicated guideline study. The log Kow of Sodium chlorate was evaluated in a GLP and reliable experimental test showing a Log Kow <-2.9. The water solubility of potassium chlorate was measured to be 10 times less than for sodium chlorate but is still highly soluble. It is therefore expected that the partition coefficient would be approximately 10 times less than that of the sodium salt. For this reason a log Kow of-2 has been used in the CSR