Reaction products of diazotised 2-amino-5-{[2-(sulfooxy)ethyl]sulfonyl}benzenesulfonic acid coupled with 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid under acidic conditions, further coupled with diazotised reaction products of 2,4,6-trifluoro-1,3,5-triazine with 2-[(2-anilinoethyl)sulfonyl]ethyl hydrogen sulfate and 2,4-diaminobenzenesulfonic acid (1:1:1) under alkaline conditions, potassium sodium salts

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

October 12, 2018 - October 19, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

Deviations:

not applicable

Principles of method if other than guideline:

OECD 105

GLP compliance:

yes (incl. QA statement)

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

high-performance liquid chromatography

Key result

Type:

log Pow

Partition coefficient:

<= -5.7

Temp.:

20 °C

Remarks on result:

other: calculated based on maximum solubility in each solvent

Remarks:

pH not determined

Preliminary visual estimation of the n-octanol solubility

Defined amounts of the test item were stirred with increasing volumes of n-octanol at room temperature and visually checked for any undissolved particles.

Table: Results of the preliminary visual estimation of the n-octanol solubility

Amount of test item / mg	Added volume of n-octanol / mL	Total volume of n-octanol / mL	Stirring time / h	Appearance of mixture
5.1	10	10	1	not dissolved
	90	100	~64	not dissolved

According to this preliminary test the solubility of the test item in n-octanol was below 51 mg/L (without correction for the purity).

Calculation of the partition coefficient log P_OW from the preliminary test

The partition coefficient P_OWmay be estimated from the saturation concentrations in n-octanol and water. The estimated partition coefficient was calculated with the water solubility data determined in project PS20180303-4 (preliminary test: c_S > 182 g/L) and the data obtained above. It was calculated to be: log P_OW < -3.6.

Due to the calculations the partition coefficient was estimated based on the ratio of the solubilities in water and octanol. The octanol solubility was determined using the flask method.The shake flask method and the HPLC method were not applicable due to the low log P_OW and as the test item is surface-active (see report PS20180303-3).

Determination of the solubility in n-octanol: Flask method

The individual saturation solubility of the test item in n-octanol was performed within this study. After that, the partition coefficient was estimated based on the ratio of the test item solubility in n-octanol and water. The flask method was performed as described above. The data for the evaluation are given in Table 7. The n-octanol solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table 7.

 Table: n-Octanol solubility experiments of the test item

Experiment	24 h experiment	48 h experiment	72 h experiment	blank experiment (72 h)
Amount of test item / mg	5.5	5.5	5.5	--
Amount of octanol / mL	20	20	20	20
Stirring time at 30 °C / h	24	48	72	72
Dilution factor	1.25	1.25	1.25	1.25
Results for main constituent 1
Measured concentration / mg/L	<0.205 / <0.205	<0.205 / <0.205	<0.205 / <0.205	-- / --
Mean concentration / mg/L	<0.205	<0.205	<0.205	--
n-Octanol solubility / mg/L	<0.164	<0.164	<0.164	--
Results for main constituent 2
Measured concentration / mg/L	<0.124 / <0.124	<0.124 / <0.124	<0.124 / <0.124	-- / --
Mean concentration / mg/L	<0.124	<0.124	<0.124	--
n-Octanol solubility / mg/L	<0.099	<0.099	<0.099	--

The n-octanol solubility of the test item at 20 °C was determined to be

< 0.16 mg/L for main constituent 1

< 0.10 mg/L for main constituent 2

resulting in a total n-octanol solubility of

< 0.26 mg/L main constituent 1 & 2

Calculation of the partition coefficient log P_OW from the individual solubilities

In the project PS20180303-4 the water solubility of the test item at 20 °C was determined to be

81.1 g/L for main constituent 1 and

47.4 g/L for main constituent 2,

resulting in a total water solubility of

128.5 g/L main constituent 1 & 2.

Within this project the n-octanol solubility of the test item at 20 °C was determined to be

< 0.16 mg/L for main constituent 1

< 0.10 mg/L for main constituent 2

resulting in a total n-octanol solubility of

< 0.26 mg/L main constituent 1 & 2

 

The partition coefficient P_OW of the test item was determined to be:          

For main constituent 1:        log P_OW<  -5.7

For main constituent 2:        log P_OW<  -5.7

For main constituent 1&2:    log P_OW<  -5.7

Executive summary:

The partition coefficient (n-octanol/water) of the test item was estimated based on the ratio of the individual solubilities of the test item in water and n-octanol. The solubilities were determined according to the flask method.The shake flask method and the HPLC method were not applicable due to the low log P_OW.

It was found to be:

log P_OW < -5.7

for main constituent 1, main constituent 2, and main constituent 1 & 2.

Description of key information

The partition coefficient (n-octanol/water) of the test item was estimated based on the ratio of the individual solubilities of the test item in water and n-octanol. The solubilities were determined according to the flask method.The shake flask method and the HPLC method were not applicable due to the low log P_OW.

It was found to be:

log P_OW < -5.7

for main constituent 1, main constituent 2, and main constituent 1 & 2.