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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
13 April, 2018 - 20 June, 2018.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 123 (Partition Coefficient (1-Octanol / Water), Slow-Stirring Method)
Qualifier:
according to guideline
Guideline:
EU Method A.23 Partition Coefficient (1-Octanol/Water): Slow-Stirring Method
GLP compliance:
no
Type of method:
slow-stirring method
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
Batch: DSP-001.
Analytical method:
high-performance liquid chromatography
Type:
log Pow
Partition coefficient:
>= -0.95 - <= 0.53
Temp.:
25 °C
pH:
6.8
Remarks on result:
not determinable
Remarks:
No reliable quantitive value could be determined due to low mass balance.
Details on results:
Sample concentrations were much lower than expected - the sample peak areas were less than that of the lowest standard (1 mg/L) ranging from 0.09-0.64 mg/L organic phase and 0.19-0.80 mg/L in the aqueous phase.
Although this is not ideal, it was considered that to re-analyse with a lower calibration range was not necessary because, with the mass recovery being so low (0.95%), highly accurately sample results was a secondary issue and would not have changed the direction of the test.
The result for the stock solution showed that the analysis itself was not an issue with it being close to the “as weighted in” concentration. The calibration curves were also acceptable.
The reason for the very low mass balance was attributed to the surface active properties of the test item. It is known that surface active substances can congregate at the interface of the organic and aqueous phases and which indicates that the method is not applicable. The surface tension of the test item demonstrated it is highly surface active with a result of 36.5 mN/m. This property was also the reason why the flask-shake (OECD 107) and HPLC (OECD 117) methods would not have been applicable.
Conclusions:
Determination of the partition coefficient of the test item at 25°C was attempted using the slow-stirring method in accrodance with OECD Test Guideline 123.
However, due to the surface active properties of the test item and congregation at the interface of the phases, a very low mass balance was observed.
This meant that the test method was not applicable and therefore, a reliable value for the partition coefficient was not determined.
Endpoint:
partition coefficient
Type of information:
other: Endpoint Expert Assessment
Adequacy of study:
key study
Study period:
August, 2018.
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Software:
US EPA Estimation Program Interface (EPI) Suite version 4.11.

Identifiers:
Diammonium 1,1-methylenebis((phenylmethyl) naphthalene-2-sulphonate)
C35H26O6S2.(NH4)2
Mol weight of salt 642.79 gmol -1
(anion portion 606.71 gmol -1)

Benzyl methylene-bis-naphthalene-2-sulphonic acid ammonium salt
C28H21O3S.NH4
Mol weight of salt 455.58 gmol -1
(anion portion 437.54 gmol -1)

Isomers of Benzyl methylene-bis-naphthalene trisulphonic acid ammonium salt
C28H19O9S3.(NH4)3
Mol weight of salt 649.76 gmol -1
(anion portion 595.64 gmol -1)

Applicability domain:
The molecular weights of the substances were within the accepted molecular weight range (18.02–719.92 g mol -1) for reliable log P estimation although some constituents are toward the top end of this range.
Qualifier:
no guideline required
Principles of method if other than guideline:
- Principle of test: Screening procedure used to examine the partition coefficient n-octanol/water in terms of the chemical functionality present within the substance with the support of computational prediction models.
- Short description of test conditions: Using the US EPA Estimation Program Interface (EPI) Suite version 4.11, the partition coefficients of the constituents of the substance were estimated. The molecular weights of the substances were within the accepted molecular weight range for reliable log P estimation.
- Parameters analysed / observed: Potential of 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-coco acyl derivs., hydroxides, inner salts to partition to octanol.
GLP compliance:
no
Type of method:
calculation method (fragments)
Partition coefficient type:
octanol-water
Key result
Remarks on result:
other: Quantitative result not determined as no test was performed
Conclusions:
According to the structural assessment and (Q)SAR modelling carried out on 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-coco acyl derivs., hydroxides, inner salts, the constituents are predicted to display a range of log Pow values (-4.30 to +0.61) depending on their structure. The main C12 constituent (ca. 42%) is predicted to have a Log Pow of -2.34.
Executive summary:

1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-coco acyl derivs., hydroxides, inner salts was assessed in terms of partition coefficient n-octanol/water using a (Q)SAR tool.

According to the (Q)SAR modelling carried out on the constituents, the predicted log Pow values range from -4.30 to +0.61, indicating that they are likely to be soluble in water and less likely to partition into the n-octanol phase.

Description of key information

Test

Determination of the partition coefficient of the substance at 25°C was attempted using the slow-stirring method in accrodance with OECD Test Guideline 123. However, due to the surface active properties of the test item and congregation at the interface of the phases, a very low mass balance was observed. This meant that the test method was not applicable and therefore, a reliable value for the partition coefficient could not be determined.

QSAR prediction

Due to the lack of reliable results of the experimental study 1-Propanaminium, N-(3-aminopropyl)-2-hydroxy-N,N-dimethyl-3-sulfo-, N-coco acyl derivs., hydroxides, inner salts was assessed in terms of partition coefficient n-octanol/water using a (Q)SAR tool. According to the (Q)SAR modelling carried out on the constituents, the predicted Log Pow values range from -4.30 to +0.61, indicating that they are likely to be soluble in water and less likely to partition into the n-octanol phase. The main C12 constituent (ca. 42%) is predicted to have a Log Pow of -2.34.

Key value for chemical safety assessment

Log Kow (Log Pow):
0.61
at the temperature of:
25 °C

Additional information