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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Study period:
2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Reason / purpose:
reference to other study
Reason / purpose:
reference to other study
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Version / remarks:
Computational approach in OECD Guideline 107
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
EU Method A.8 (Partition Coefficient - Shake Flask Method)
Version / remarks:
Computational approach in EU A.8
Deviations:
no
Principles of method if other than guideline:
Firstly, the water solubility of the test substance was determined based on CMC and the n-octanol solubility according to OECD Guideline 105. The partition coefficient was then calculated from ratio of the solubility of the test substance in octanol and water.
GLP compliance:
no
Type of method:
estimation method (solubility ratio)
Partition coefficient type:
octanol-water
Analytical method:
other: Computational approach
Key result
Type:
Pow
Partition coefficient:
ca. 88.833
Temp.:
20 °C
Remarks on result:
other: based on ratio of solubility in n-octanol and water/CMC
Key result
Type:
log Pow
Partition coefficient:
ca. 1.95
Temp.:
20 °C
Remarks on result:
other: based on ratio of solubility in n-octanol and water/CMC
Details on results:
-Solubility of the test substance in n-octanol: 53.3 g/L (ref: Envigo, 2018)
-Solubility of the test substance in water (based on CMC): 600 mg/L(ref: Envigo, 2018)

The log Pow was calculated according to the equation:
Pow = solubility of the test substance in n-octanol / solubility of the test substance in water
= 53,300 mg/L / 600 mg/L
= 88.83333

Log Pow: 1.95
Conclusions:
Under the study conditions, the calculated partition coefficient (log Pow) of the test substance, based on solubility in n-octanol and water, was determined to be 1.95 at 20°C.
Executive summary:

A study was conducted to determine partition coefficient of the test substance, from the ratio of the solubility in n-octanol and water, according to the calculation method specified in the OECD Guideline 107 and EU Method A.8. The water solubility of the test substance was determined to be 600 mg/L based on critical micelle concentration (CMC) and the n-octanol solubility was determined to be 53.3 g/L according to OECD Guideline 105 (Envigo, 2018). Under the study conditions, the calculated partition coefficient (log Pow) of the test substance, based on solubility in n-octanol and water, was calculated to be 1.95 at 20°C (Croda, 2018).

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification
Justification for type of information:
QSAR prediction from an well known and acknowledged tool. See below under 'Overall remarks, attachments' for applicability domain.
Qualifier:
according to
Guideline:
other: REACH guidance on QSARs: Chapter R.6. QSARs and grouping of chemicals
Principles of method if other than guideline:
Since the test substance is a UVCB with similar constituents varying mainly in carbon chain lengths, the partition coefficient values were estimated for the individual components followed by the determination of an overall weighted-average value using the mole fractions of all the individual components.
Key result
Type:
log Pow
Partition coefficient:
ca. 16.24
Temp.:
25 °C
Remarks on result:
other: Weighted average partition coefficient estimation using KOWWIN v1.68

QSAR Full test results:

Chemical names SMILES Mole fraction Xi = (mi/Mi)/∑ (mi/Mi) Log kow Log kow*xi Domain evaluation
1‐(2‐hexadecanamidoethyl)‐1‐methyl‐2‐pentadecyl‐4,5‐dihydro‐1H‐imidazol‐1‐ium methyl sulfate CCCCCCCCCCCCCCCC(=O)NCC[N]1(C)([O]S(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCC 0.005097 1.23E+01 0.06 ID - molecular weight, OD- molecular fragments
2‐heptadecyl‐1‐methyl‐1‐(2‐octadecanamidoethyl)‐
4,5‐dihydro‐1H‐imidazol‐1‐ium methyl sulfate
CCCCCCCCCCCCCCCCCC(=O)NCC[N]1(C)([O]S(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCC 0.169157 1.43E+01 2.42 ID - molecular weight, OD- molecular fragments
1‐(2‐icosanamidoethyl)‐1‐methyl‐2‐nonadecyl‐4,5‐
dihydro‐1H‐imidazol‐1‐ium methyl sulfate

CCCCCCCCCCCCCCCCCCCC(=O)NCC[N]1(C)([O]S(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCCCC  0.457798 1.63E+01 7.44 ID - molecular weight, OD- molecular fragments
1‐(2‐docosanamidoethyl)‐2‐henicosyl‐1‐methyl‐4,5‐
dihydro‐1H‐imidazol‐1‐ium methyl sulfate

CCCCCCCCCCCCCCCCCCCCCC(=O)NCC[N]1(C)([O]S(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCCCCCC 0.198683 1.82E+01 3.62 ID - molecular weight, OD- molecular fragments
2‐henicosyl‐1‐(2‐hexadecanamidoethyl)‐1‐methyl‐4,5‐
dihydro‐1H‐imidazol‐1‐ium methyl sulfate

CCCCCCCCCCCCCCCC(=O)NCC[N]1(C)([O]S(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCCCCCC 0.088257 1.53E+01 1.35 ID - molecular weight, OD- molecular fragments
2‐henicosyl‐1‐(2‐icosanamidoethyl)‐1‐methyl‐4,5‐dihydro‐1H‐imidazol‐1‐ium methyl sulfate CCCCCCCCCCCCCCCCCCCC(=O)NCC[N]1(C)([O]S(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCCCCCC 0.068432 1.72E+01 1.18 ID - molecular weight, OD- molecular fragments
2‐heptadecyl‐1‐(2‐hexadecanamidoethyl)‐1‐methyl‐4,5‐dihydro‐1H‐imidazol‐1‐ium methyl sulfate
CCCCCCCCCCCCCCCC(=O)NCC[N]1(C)([O]S(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCC 0.012575 1.33E+01 0.17 ID - molecular weight, OD- molecular fragments
    1.0000000   16.24  

ID : In domain, MW - Molecular weight

Kow
       
                 Log Kow(version 1.68 estimate): 12.33      
  Domain evaluation    
SMILES : CCCCCCCCCCCCCCCC(=O)NCCN1(C)(OS(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCC   MW (Training set) MW (Validation)
CHEM  :  ID 719.92 991.15
MOL FOR: C38 H77 N3 O5 S1       
MOL WT : 688.11      
-------+-----+--------------------------------------------+---------+--------      
 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE       
-------+-----+--------------------------------------------+---------+--------   Training set Validation set
 Frag | 4 | -CH3   [aliphatic carbon]               | 0.5473 | 2.1892 ID 13 20
 Frag | 32 | -CH2-  [aliphatic carbon]               | 0.4911 | 15.7152 OD 18 28
 Frag | 1 | C    [aliphatic carbon - No H, not tert] | 0.9723 | 0.9723 ID 3 11
 Frag | 1 | -O-    [oxygen, aliphatic attach]       |-1.2566 | -1.2566 ID 5 12
 Frag | 1 | -NH-   [aliphatic attach]               |-1.4962 | -1.4962 ID 4 5
 Frag | 1 | -C(=O)N [aliphatic attach]              |-0.5236 | -0.5236 ID 4 5
 Frag | 1 | -N=C    [aliphatic attach]              |-0.0010 | -0.0010 ID 2 3
 Frag | 1 | >N< [+5 valence; single bonds;no H attach]|-6.6000 | -6.6000 ID 1 1
 Frag | 1 | -O-SO2-O-    [sulfate, linear]          | 1.3500 | 1.3500 ID 1 1
 Frag | 1 | {-O- or -S-} to nitrogen (+5 valence)]   | 1.7500**| 1.7500      
 Const |    | Equation Constant                        |        | 0.2290      
-------+-----+--------------------------------------------+---------+--------      
 NOTE |    | An estimated coefficient (**) used                 |      
-------+-----+--------------------------------------------+---------+--------      
                                                        Log Kow  = 12.3283      
       
       
       
       
                 Log Kow(version 1.68 estimate): 14.29      
  Domain evaluation    
SMILES : CCCCCCCCCCCCCCCCCC(=O)NCCN1(C)(OS(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCC   MW (Training set) MW (Validation)
CHEM  :  ID 719.92 991.15
MOL FOR: C42 H85 N3 O5 S1       
MOL WT : 744.22      
-------+-----+--------------------------------------------+---------+--------      
 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE       
-------+-----+--------------------------------------------+---------+--------   Training set Validation set
 Frag | 4 | -CH3   [aliphatic carbon]               | 0.5473 | 2.1892 ID 13 20
 Frag | 36 | -CH2-  [aliphatic carbon]               | 0.4911 | 17.6796 OD 18 28
 Frag | 1 | C    [aliphatic carbon - No H, not tert] | 0.9723 | 0.9723 ID 3 11
 Frag | 1 | -O-    [oxygen, aliphatic attach]       |-1.2566 | -1.2566 ID 5 12
 Frag | 1 | -NH-   [aliphatic attach]               |-1.4962 | -1.4962 ID 4 5
 Frag | 1 | -C(=O)N [aliphatic attach]              |-0.5236 | -0.5236 ID 4 5
 Frag | 1 | -N=C    [aliphatic attach]              |-0.0010 | -0.0010 ID 2 3
 Frag | 1 | >N< [+5 valence; single bonds;no H attach]|-6.6000 | -6.6000 ID 1 1
 Frag | 1 | -O-SO2-O-    [sulfate, linear]          | 1.3500 | 1.3500 ID 1 1
 Frag | 1 | {-O- or -S-} to nitrogen (+5 valence)]   | 1.7500**| 1.7500      
 Const |    | Equation Constant                        |        | 0.2290      
-------+-----+--------------------------------------------+---------+--------      
 NOTE |    | An estimated coefficient (**) used                 |      
-------+-----+--------------------------------------------+---------+--------      
                                                        Log Kow  = 14.2927      
       
       
       
       
                 Log Kow(version 1.68 estimate): 16.26      
 
SMILES : CCCCCCCCCCCCCCCCCCCC(=O)NCCN1(C)(OS(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCC Domain evaluation    
        CC   MW (Training set) MW (Validation)
CHEM  :  ID 719.92 991.15
MOL FOR: C46 H93 N3 O5 S1       
MOL WT : 800.33      
-------+-----+--------------------------------------------+---------+--------      
 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE       
-------+-----+--------------------------------------------+---------+--------   Training set Validation set
 Frag | 4 | -CH3   [aliphatic carbon]               | 0.5473 | 2.1892 ID 13 20
 Frag | 40 | -CH2-  [aliphatic carbon]               | 0.4911 | 19.6440 OD 18 28
 Frag | 1 | C    [aliphatic carbon - No H, not tert] | 0.9723 | 0.9723 ID 3 11
 Frag | 1 | -O-    [oxygen, aliphatic attach]       |-1.2566 | -1.2566 ID 5 12
 Frag | 1 | -NH-   [aliphatic attach]               |-1.4962 | -1.4962 ID 4 5
 Frag | 1 | -C(=O)N [aliphatic attach]              |-0.5236 | -0.5236 ID 4 5
 Frag | 1 | -N=C    [aliphatic attach]              |-0.0010 | -0.0010 ID 2 3
 Frag | 1 | >N< [+5 valence; single bonds;no H attach]|-6.6000 | -6.6000 ID 1 1
 Frag | 1 | -O-SO2-O-    [sulfate, linear]          | 1.3500 | 1.3500 ID 1 1
 Frag | 1 | {-O- or -S-} to nitrogen (+5 valence)]   | 1.7500**| 1.7500      
 Const |    | Equation Constant                        |        | 0.2290      
-------+-----+--------------------------------------------+---------+--------      
 NOTE |    | An estimated coefficient (**) used                 |      
-------+-----+--------------------------------------------+---------+--------      
                                                        Log Kow  = 16.2571      
       
       
       
       
                 Log Kow(version 1.68 estimate): 18.22      
       
SMILES : CCCCCCCCCCCCCCCCCCCCCC(=O)NCCN1(C)(OS(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCC Domain evaluation    
        CCCCCC   MW (Training set) MW (Validation)
CHEM  :  ID 719.92 991.15
MOL FOR: C50 H101 N3 O5 S1       
MOL WT : 856.44      
-------+-----+--------------------------------------------+---------+--------      
 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE       
-------+-----+--------------------------------------------+---------+--------   Training set Validation set
 Frag | 4 | -CH3   [aliphatic carbon]               | 0.5473 | 2.1892 ID 13 20
 Frag | 44 | -CH2-  [aliphatic carbon]               | 0.4911 | 21.6084 OD 18 28
 Frag | 1 | C    [aliphatic carbon - No H, not tert] | 0.9723 | 0.9723 ID 3 11
 Frag | 1 | -O-    [oxygen, aliphatic attach]       |-1.2566 | -1.2566 ID 5 12
 Frag | 1 | -NH-   [aliphatic attach]               |-1.4962 | -1.4962 ID 4 5
 Frag | 1 | -C(=O)N [aliphatic attach]              |-0.5236 | -0.5236 ID 4 5
 Frag | 1 | -N=C    [aliphatic attach]              |-0.0010 | -0.0010 ID 2 3
 Frag | 1 | >N< [+5 valence; single bonds;no H attach]|-6.6000 | -6.6000 ID 1 1
 Frag | 1 | -O-SO2-O-    [sulfate, linear]          | 1.3500 | 1.3500 ID 1 1
 Frag | 1 | {-O- or -S-} to nitrogen (+5 valence)]   | 1.7500**| 1.7500      
 Const |    | Equation Constant                        |        | 0.2290      
-------+-----+--------------------------------------------+---------+--------      
 NOTE |    | An estimated coefficient (**) used                 |      
-------+-----+--------------------------------------------+---------+--------      
                                                        Log Kow  = 18.2215      
       
       
       
       
                 Log Kow(version 1.68 estimate): 15.27      
       
SMILES : CCCCCCCCCCCCCCCC(=O)NCCN1(C)(OS(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCCCCCC Domain evaluation    
            MW (Training set) MW (Validation)
CHEM  :  ID 719.92 991.15
MOL FOR: C44 H89 N3 O5 S1       
MOL WT : 772.28      
-------+-----+--------------------------------------------+---------+--------      
 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE       
-------+-----+--------------------------------------------+---------+--------   Training set Validation set
 Frag | 4 | -CH3   [aliphatic carbon]               | 0.5473 | 2.1892 ID 13 20
 Frag | 38 | -CH2-  [aliphatic carbon]               | 0.4911 | 18.6618 OD 18 28
 Frag | 1 | C    [aliphatic carbon - No H, not tert] | 0.9723 | 0.9723 ID 3 11
 Frag | 1 | -O-    [oxygen, aliphatic attach]       |-1.2566 | -1.2566 ID 5 12
 Frag | 1 | -NH-   [aliphatic attach]               |-1.4962 | -1.4962 ID 4 5
 Frag | 1 | -C(=O)N [aliphatic attach]              |-0.5236 | -0.5236 ID 4 5
 Frag | 1 | -N=C    [aliphatic attach]              |-0.0010 | -0.0010 ID 2 3
 Frag | 1 | >N< [+5 valence; single bonds;no H attach]|-6.6000 | -6.6000 ID 1 1
 Frag | 1 | -O-SO2-O-    [sulfate, linear]          | 1.3500 | 1.3500 ID 1 1
 Frag | 1 | {-O- or -S-} to nitrogen (+5 valence)]   | 1.7500**| 1.7500      
 Const |    | Equation Constant                        |        | 0.2290      
-------+-----+--------------------------------------------+---------+--------      
 NOTE |    | An estimated coefficient (**) used                 |      
-------+-----+--------------------------------------------+---------+--------      
                                                        Log Kow  = 15.2749      
       
       
       
       
                 Log Kow(version 1.68 estimate): 17.24      
       
SMILES : CCCCCCCCCCCCCCCCCCCC(=O)NCCN1(C)(OS(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCC Domain evaluation    
        CCCC   MW (Training set) MW (Validation)
CHEM  :  ID 719.92 991.15
MOL FOR: C48 H97 N3 O5 S1       
MOL WT : 828.39      
-------+-----+--------------------------------------------+---------+--------      
 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE       
-------+-----+--------------------------------------------+---------+--------   Training set Validation set
 Frag | 4 | -CH3   [aliphatic carbon]               | 0.5473 | 2.1892 ID 13 20
 Frag | 42 | -CH2-  [aliphatic carbon]               | 0.4911 | 20.6262 OD 18 28
 Frag | 1 | C    [aliphatic carbon - No H, not tert] | 0.9723 | 0.9723 ID 3 11
 Frag | 1 | -O-    [oxygen, aliphatic attach]       |-1.2566 | -1.2566 ID 5 12
 Frag | 1 | -NH-   [aliphatic attach]               |-1.4962 | -1.4962 ID 4 5
 Frag | 1 | -C(=O)N [aliphatic attach]              |-0.5236 | -0.5236 ID 4 5
 Frag | 1 | -N=C    [aliphatic attach]              |-0.0010 | -0.0010 ID 2 3
 Frag | 1 | >N< [+5 valence; single bonds;no H attach]|-6.6000 | -6.6000 ID 1 1
 Frag | 1 | -O-SO2-O-    [sulfate, linear]          | 1.3500 | 1.3500 ID 1 1
 Frag | 1 | {-O- or -S-} to nitrogen (+5 valence)]   | 1.7500**| 1.7500      
 Const |    | Equation Constant                        |        | 0.2290      
-------+-----+--------------------------------------------+---------+--------      
 NOTE |    | An estimated coefficient (**) used                 |      
-------+-----+--------------------------------------------+---------+--------      
                                                        Log Kow  = 17.2393      
       
       
       
       
       
                 Log Kow(version 1.68 estimate): 13.31      
  Domain evaluation    
SMILES : CCCCCCCCCCCCCCCC(=O)NCCN1(C)(OS(=O)(=O)OC)CCN=C1CCCCCCCCCCCCCCCCC   MW (Training set) MW (Validation)
CHEM  :  ID 719.92 991.15
MOL FOR: C40 H81 N3 O5 S1       
MOL WT : 716.17      
-------+-----+--------------------------------------------+---------+--------      
 TYPE | NUM |       LOGKOW FRAGMENT DESCRIPTION        | COEFF | VALUE       
-------+-----+--------------------------------------------+---------+--------   Training set Validation set
 Frag | 4 | -CH3   [aliphatic carbon]               | 0.5473 | 2.1892 ID 13 20
 Frag | 34 | -CH2-  [aliphatic carbon]               | 0.4911 | 16.6974 OD 18 28
 Frag | 1 | C    [aliphatic carbon - No H, not tert] | 0.9723 | 0.9723 ID 3 11
 Frag | 1 | -O-    [oxygen, aliphatic attach]       |-1.2566 | -1.2566 ID 5 12
 Frag | 1 | -NH-   [aliphatic attach]               |-1.4962 | -1.4962 ID 4 5
 Frag | 1 | -C(=O)N [aliphatic attach]              |-0.5236 | -0.5236 ID 4 5
 Frag | 1 | -N=C    [aliphatic attach]              |-0.0010 | -0.0010 ID 2 3
 Frag | 1 | >N< [+5 valence; single bonds;no H attach]|-6.6000 | -6.6000 ID 1 1
 Frag | 1 | -O-SO2-O-    [sulfate, linear]          | 1.3500 | 1.3500 ID 1 1
 Frag | 1 | {-O- or -S-} to nitrogen (+5 valence)]   | 1.7500**| 1.7500      
 Const |    | Equation Constant                        |        | 0.2290      
-------+-----+--------------------------------------------+---------+--------      
 NOTE |    | An estimated coefficient (**) used                 |      
-------+-----+--------------------------------------------+---------+--------      
                                                        Log Kow  = 13.3105      
Conclusions:
Using the KOWWIN v1.68 program (EPI Suite v4.00 - v4.11), the weigthted average partition coefficient of the test substance was calculated to be 16.24.
Executive summary:

The partition coefficient value for the test substance, 'di-C18-22 AAEMIM-MS', was estimated using the KOWWIN v1.68 program (EPI Suite v4.00 - v4.11). Since the test substance is a UVCB with similar constituents varying mainly in carbon chain lengths, the partition coefficient values were estimated for the individual components followed by the determination of an overall weighted-average value using the mole fractions of all the individual components. SMILES codes were used as the input parameter for the partition coefficient estimation for the individual constituents. The estimated partition coefficient values for the constituents ranged from 10.23 to 18.2, leading to an weighted average partition coefficient value of the test substance as 16.24 (US EPA, 2018). Based on the estimated partition coefficient value of 16.24, the test substance is considered to be not bioavailable - difficult to measure experimentally (US EPA, 2012). The estimates for the major constituents are considered to be reliable with restrictions, as they do not completely fall within of the applicability domain.

Endpoint:
partition coefficient
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
Calculation method
Adequacy of study:
weight of evidence
Study period:
2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Refer to section 13 of IUCLID for details on the read-across justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.
Reason / purpose:
read-across source
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Version / remarks:
Computational approach in OECD Guideline 107
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
EU Method A.8 (Partition Coefficient - Shake Flask Method)
Version / remarks:
Computational approach in EU A.8
Deviations:
no
Principles of method if other than guideline:
Firstly, the water solubility of the test substance was determined based on CMC and the n-octanol solubility according to OECD Guideline 105. The partition coefficient was then calculated from ratio of the solubility of the test substance in octanol and water.
GLP compliance:
no
Type of method:
estimation method (solubility ratio)
Partition coefficient type:
octanol-water
Analytical method:
other: Computational approach
Key result
Type:
Pow
Partition coefficient:
ca. 29 000 - ca. 33 000
Temp.:
20 °C
Remarks on result:
other: based on ratio of solubility in n-octanol and water.
Key result
Type:
log Pow
Partition coefficient:
ca. 4.46 - ca. 4.52
Temp.:
20 °C
Remarks on result:
other: based on ratio of solubility in n-octanol and water.
Details on results:
-Solubility of the test substance in n-octanol: 29 to 33 g/L (ref: Envigo, 2018)
-Solubility of the test substance in water assesed based on weight of evidence approach : <=1 mg/L(refer to the water solubility endpoint summary)

The log Pow was calculated according to the equation with lower limit of n-octanol solubility.
Pow = solubility of the test substance in n-octanol / solubility of the test substance in water
= 29000 mg/L / 1 mg/L
= 29000

Log Pow: 4.4623

The log Pow was calculated according to the equation with upper of n-octanol solubility.
Pow = solubility of the test substance in n-octanol / solubility of the test substance in water
= 33000 mg/L / 1 mg/L
= 33000

Log Pow: 4.518

Based on n-octanol solubility ranges Log Pow of the test substance in range of 4.4623 to 4.518.
Conclusions:
Under the study conditions, the calculated partition coefficient (log Pow) of the read across substance, based on solubility in n-octanol and water (based on WoE), was determined to be 4.46-4.52 at 20°C.
Executive summary:

A study was conducted to determine partition coefficient of the read across substance, 'di-C16 and C18-unsatd. AAEMIM-MS', from the ratio of the solubility in n-octanol and water, according to the calculation method specified in the OECD Guideline 107 and EU Method A.8. The water solubility of the test substance was assessed based on weight of evidance approach is <=1 mg/L based on critical micelle concentration (CMC) and the n-octanol solubility range was determined to be 29 to 33 g/L according to OECD Guideline 105 (Envigo, 2018). The calculated partition coefficient (log Pow) of the test substance, based on solubility in n-octanol ranges 29 and 33 g/L and water, was calculated to be 4.46 to 4.52, respectively. Under the study conditions, the calculated partition coefficient (log Pow) of the read across substance, based on solubility in n-octanol and water (based on WoE), was determined to be 4.46-4.52 at 20°C (Croda, 2018).

Endpoint:
partition coefficient
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Remarks:
Calculation method
Adequacy of study:
weight of evidence
Study period:
2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Refer to section 13 of IUCLID for details on the read-across justification. The study with the read across substance is considered sufficient to fulfil the information requirements as further explained in the provided endpoint summary.
Reason / purpose:
read-across source
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)
Version / remarks:
Computational approach in OECD Guideline 107
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
EU Method A.8 (Partition Coefficient - Shake Flask Method)
Version / remarks:
Computational approach in EU A.8
Deviations:
no
Principles of method if other than guideline:
Firstly, the water solubility of the test substance was determined based on CMC and the n-octanol solubility according to OECD Guideline 105. The partition coefficient was then calculated from ratio of the solubility of the test substance in octanol and water.
GLP compliance:
no
Type of method:
estimation method (solubility ratio)
Partition coefficient type:
octanol-water
Analytical method:
other: Computational approach
Key result
Type:
Pow
Partition coefficient:
ca. 80 000 - ca. 100 000
Temp.:
20 °C
Remarks on result:
other: based on ratio of solubility in n-octanol and weight of evidence water solubility.
Key result
Type:
log Pow
Partition coefficient:
ca. 4.9 - ca. 5
Temp.:
20 °C
Remarks on result:
other: based on ratio of solubility in n-octanol and weight of evidence water solubility.
Details on results:
-Solubility of the test substance in n-octanol: 80 to 100 g/L (ref: Envigo, 2018)
-Solubility of the test substance in water assesed based on weight of evidence approach : <=1 mg/L (refer to the water solubility endpoint summary).

The log Pow was calculated according to the equation with lower limit of n-octanol solubility.
Pow = solubility of the test substance in n-octanol / solubility of the test substance in water
= 80,000 mg/L / 1 mg/L
= 80000

Log Pow: 4.903

The log Pow was calculated according to the equation with upper of n-octanol solubility.
Pow = solubility of the test substance in n-octanol / solubility of the test substance in water
= 100,000 mg/L / 1 mg/L
= 100,000

Log Pow: 5

Based on n-octanol solubility ranges Log Pow of the test substance in range of 4.903 to 5.
Conclusions:
Under the study conditions, the calculated partition coefficient (log Pow) of the read across substance, based on solubility in n-octanol and water, was determined to be 4.9 to 5 at 20°C.
Executive summary:

A study was conducted to determine partition coefficient of the read across substance, 'di-C16-18-satd. and C18-24-unsatd. AAEMIM-MS', from the ratio of the solubility in n-octanol and water, according to the calculation method specified in the OECD Guideline 107 and EU Method A.8. The water solubility of the test substance was assessed based on weight of evidance approach and was concluded to be <= 1 mg/L and the n-octanol solubility range was determined to be 80 to 100 g/L according to OECD Guideline 105 (Envigo, 2018). The calculated partition coefficient (log Pow) of the test substance, based on solubility in n-octanol ranges 80 and 100 g/L and water, was calculated to be 4.9 to 5, respectively. Under the study conditions, the calculated partition coefficient (log Pow) of the read across substance, based on solubility in n-octanol and water, was determined to be 4.9 to 5 at 20°C (Croda, 2018).

Description of key information

The partition coefficient of the test substance was calculated from the ratio of the solubility of test substance in n-octanol and water, according to a calculation method specified in OECD Guideline 107 and EU Method A.8 (Croda, 2018), as well as using QSAR model, KOWWIN (US EPA, 2018).

Key value for chemical safety assessment

Log Kow (Log Pow):
4
at the temperature of:
20 °C

Additional information

In absence of an reliable experimental water solubility study, to calculate the log Kow value of the test substance, the endpoint has been assessed using a weight of evidence (WoE) approach, as presented below:

- Calculated log Kow = 1.95 at 20 °C; (based on solubility ratio);

- Weighted average QSAR based water solubility of test substance: 16.24 at 25 °C using KOWWIN v1.68 model (US EPA, 2018); the estimates for the major constituents were considered to be reliable with restrictions, as they do not completely fall within of the applicability domain.

- Calculated log Kow of similar Croda substances:

(a)Imidazolium compounds, 2-(C9-19 and C9-19-unsatd. alkyl)-1-[(C10-20 and C10-20-unsatd. amido)ethyl]-4,5-dihydro-1-Me, Me sulfates (di-C16 and C18-unsatd. AAEMIM-MS): 4.46-4.52 at 20°C (calculated based on solubility ratio); indicating high lipophilicity;

(b) Rape oil, reaction products with diethylenetriamine, di-Me sulfate-quaternized (di-C16-18 satd. and C18-24 unsatd. AAEMIM-MS):4.9-5 at 20°C (calculated based on solubility ratio); indicating high lipophilicity;

Overall both substances were concluded to have high lipophilicity (log Kow >4), based on structure/nature of the substance along with weight of evidence from other similar substances and QSAR predictions (REACH dossiers – CAS: 92201 -88-2 and CAS: 98219-63-7).

- Experimental log Kow of similar substances:

(a) Fatty acids, C16-18 (even numbered) and C18 unsatd., reaction products with diethylene triamine, di-Me sulfate quaternized (di- C16-18 and C18-unsatd. AAEMIM-MS): 4.7 at 22°C (calculated using solubility ratio) (REACH dossier, EC: 937-237-2);

(b) Imidazolium compounds, 2-C17-unsatd.-alkyl-1-(2-C18-unsatd. amidoethyl)-4,5-dihydro-N-methyl, Me sulfates (di- C18-unsatd. AAEMIM-MS): >5.7 mg/L at 22°C (calculated using solubility ratio) (REACH dossier, EC: 931-745-8); indicating high lipophilicity.

Overall, based on the above information and given the questionable CMC (see below discussion), the derived log Kow does not seem to fit with the expected behaviour of the substance. Considering the slight solubility potential of the substance, the log Kow is expected to be higher. Hence as a worst case, a weight of evidence-based log Kow of 4 has been taken forward for the hazard assessment/risk characterisation.