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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
07.03.2005-10.03.2005
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
unsuitable test system
Remarks:
unsuitable calculation due to surface-active properties of the test substance and therefore overestimating the'real' water solubility
Qualifier:
no guideline followed
Principles of method if other than guideline:
In the frame of a study conducted according to OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method) and EU Method A.8 (Partition Coefficient), the n-octanol/water partition coefficient log Kow of the test substance was estimated via the 'apparent' water solubility.
GLP compliance:
no
Type of method:
other: calculation
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
1.9
Temp.:
20 °C
pH:
ca. 3.9
Details on results:
The pH was determined in the study on water solubility cited in IUCLID section 4.8.

In the frame of a study conducted according to OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method) and EU Method A.8 (Partition Coefficient), the n-octanol/water partition coefficient log Kow of the test substance was estimated via the 'apparent' water solubility. The calculation yielded a log Kow=1.9 (Kow=200 g/L/2.5 g/L; 'apparent' water solubility=2.5 g/L at 20°C, solubility in n-octanol=200 g/L at 20°C). Due to the surface-active properties of the test substance, the 'real' water solubility is overestimated. Therefore the result should be treated with care.

Conclusions:
In the frame of a study conducted according to OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method) and EU Method A.8 (Partition Coefficient), the n-octanol/water partition coefficient log Kow of the test substance was estimated via the 'apparent' water solubility. The calculation yielded a log Kow=1.9 (Kow=200 g/L/2.5 g/L; 'apparent' water solubility=2.5 g/L at 20°C, solubility in n-octanol=200 g/L at 20°C). Due to the surface-active properties of the test substance, the 'real' water solubility is overestimated. Therefore the result should be treated with care.
Executive summary:

In the frame of a study conducted according to OECD Guideline 117 (Partition Coefficient (n-octanol / water), HPLC Method) and EU Method A.8 (Partition Coefficient), the n-octanol/water partition coefficient log Kow of the test substance was estimated via the 'apparent' water solubility. The calculation yielded a log Kow=1.9 (Kow=200 g/L/2.5 g/L; 'apparent' water solubility=2.5 g/L at 20°C, solubility in n-octanol=200 g/L at 20°C). Due to the surface-active properties of the test substance, the 'real' water solubility is overestimated. Therefore the result should be treated with care.

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 (Q)SAR model, with limited documentation / justification, but validity of model and reliability of prediction considered adequate based on a generally acknowledged source
Justification for type of information:
1. SOFTWARE
ACD/PhysChem Suite

2. MODEL (incl. version number)
ACD/PhysChem Suite for prediction of octanol-water partitioning coefficient Koc resp. LogD; ACD/Labs version B

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
Monoester:
O=C(CCCCCCCCCCCCCCCCC)OCC[N+](C)(CCO)CCO
bzw.: C25 H53 NO4
Diester:
O=C(CCCCCCCCCCCCCCCCC)OCC[N+](C)(CCOC(=O)CCCCCCCCCCCCCCCCC)CCO
bzw. C43 H87 NO5
Triester:
O=C(CCCCCCCCCCCCCCCCC)OCC[N+](C)(CCOC(=O)CCCCCCCCCCCCCCCCC)CCOC(=O)C
CCCCCCCCCCCCCCCC
bzw. C61 H121 NO6

structural formulas see attached QPRF

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
see attached QMRF

5. APPLICABILITY DOMAIN
i. descriptor domain
not information available

ii. structural fragment domain
Training substance and calculated substance have almost identical structural descriptors with one exception: substance in training data set “user database” contains exclusive esterified ethanolamine alcohol function. Free ethanolamine alcohol function as present in compound 1 and compound 2 is not represented. The influence of the missing alcohol function on the calculation result, compared to quaternary ammonium function, is expected to be minor.

6. ADEQUACY OF THE RESULT
Considerations on structural analogues:
Measured value for MDEA Esterquat (log Kow = 5.38) and calculated value for compound I with the identical number of ester groups, quaternary nitrogen but with additional polar free CH2-CH2-OH (log Kow = 5.04) seems to be comprehensible. The extrapolation on the monoester and triester is in correspondence with similar programs (EpiWin) and comparison with the few measured values.

The results are considered to be adequate for risk assessment.
Guideline:
other:
Principles of method if other than guideline:
Kow values were calculated for Mono-, Di- and Triester of TEA-Esterquat (C18 chain-length, saturated), separately, using the chemical properties prediction software ACD/Labs v12 of company Advanced Chemistry Development, Inc. (www.acdlabs.com) and experimental data of [Me-14C] MDEA Esterquat (NOTOX 489708) as training substance.
GLP compliance:
no
Type of method:
other: QSAR
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
4.77
Temp.:
25 °C
pH:
ca. 7
Remarks on result:
other: calculation method, neutral pH is assumed; Calculated (weighted) value based on measured properties of similar substances and by consideration of approximate mole fractions of Mono-, Di- and Triester of TEA-Esterquats.
Conclusions:
The mean weighted log Kow for TEA-Esterquat (C18 satd. chains) was calculated for log Kow = 4.77 (chemical properties prediction software ACD/Labs v12).
Executive summary:

Kow values for the most lipophilic Mono-, Di- and Triester species of TEA-Esterquats (C18 chain-length, saturated) were calculated separately, using the chemical properties prediction software ACD/Labs v12 of company Advanced Chemistry Development, Inc. and experimental data of [Me-14C] MDEA Esterquat (NOTOX 489708). For experimental data input to ACD/Labs, adsorption coefficients of [Me-14C] MDEA Esterquat were used as training data for calculation of the log Kow according to the Lyman-method. Individual log Kow values were -2.95 (Monoester), 5.04 (Diester) and 13.93 (Triester) of TEA-Esterquat (C18 satd). Outputs were then weighted to calculate a mean log Kow. The calculated log Kow of TEA-EQ (C18 satd) was 4.77.

Description of key information

weighted mean log Kow: 4.77
Monoester: -2.95
Diester: 5.04
Triester: 13.93

Key value for chemical safety assessment

Log Kow (Log Pow):
4.77
at the temperature of:
20 °C

Additional information

The n-Octanol/water partitioning coefficient (log Kow) of partially unsaturated TEA-Esterquat was calculated from the individual solubilities in 1-octanol and water at 20 °C, respectively. The log Kow is reported to be 1.9 at 20°C.


However, due to the surface-active properties of the test substance, the 'real' water solubility is overestimated. Therefore, the result should be treated with care.


Due to uncertainties with the measured values for surface active substances, a calculation of the n-octanol/water-partition coefficient (log Kow) was performed. Kow values fort the most lipophilic Mono-, Di- and Triester species (C18 chain-length, saturated) were calculated separately, using the chemical properties prediction software ACD/Labs v12 of company Advanced Chemistry Development, Inc. and experimental data of [Me-14C] MDEA Esterquat (NOTOX 489708). For experimental data input to ACD/Labs, adsorption coefficients of [Me-14C] MDEA Esterquat were used for calculation of the log Kow according to the Lyman-method. Individual log Kow values were -2.95 (Monoester), 5.04 (Diester) and 13.93 (Triester). Outputs were then weighted to calculate a mean log Kow. The calculated log Kow of TEA-EQ was 4.725. This value was used as a reasonable worst case for the assessment.


 


 


Supporting data on the structurally related source substance MDIPA-Esterquat C16-18 and C18 unsatd. are included to justify read-across: the log Kow was derived from a measured distribution coefficient, log Koc, between water and organic carbon of soils and sludges for this substance according to OECD guideline 106. A log Kow of 4.43 was derived.