Trichloro-12,24-dihydro-5H-naphtho[2,3-h]naphth[2'',3'':6',7']indolo[2',3':6,7]anthra[2,1,9-mna]acridine-5,10,13,18,25-pentone

Partition coefficient

Link to relevant study record(s)

Reference

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

July 17, 2018 - August 07, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: OECD 105 flask method

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD 105 flask method

Deviations:

not applicable

Principles of method if other than guideline:

OECD 105 flask method

GLP compliance:

no

Type of method:

flask method

Partition coefficient type:

octanol-water

Analytical method:

titration method

Key result

Type:

log Pow

Partition coefficient:

> 3.8

Temp.:

20 °C

Remarks on result:

other: 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.

Table1: 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
11.9	10	10	1	not dissolved
	190	200	18	not dissolved

According to this preliminary test the solubility of the test item in n-octanol was below 60 mg/L (without correction for the purity).

Calculation of the partition coefficient log P_OW from the preliminary test

The partition coefficient P_OW may 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 PS20180221-3 (c_S < 1.08 mg/L) and the data obtained above. It was calculated to be: log P_OW > 1.7.

Also the program KOWWIN (part of EPI Suite) was used for calculating the log P_OW of the test item. The calculated value was 11.6.

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 solubility of the test item in organic solvents.

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 Table2. The n-octanol solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table2.

Table2: 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	33.1	30.1	31.0	--
Amount of octanol / mL	100	100	100	100
Stirring time at 30 °C / h	24	48	72	72
Dilution factor	1	1	1	1
Density of the sample / g/mL	0.825	0.823	0.825	0.824
Measured concentration / g Cl /100g	0.1	< 0.1	0.1	< 0.1
Mean concentration / g Cl/L	0.83	< 0.82	0.83	< 0.82
n-Octanol solubility / g/L^1)	6.5	< 6.5	6.5	--

Remark: 1) Calculated with a content of 12.6 % Cl (w/w) of the test item.

The n-octanol solubility of the test item at 20 °C was determined to be 6.5g/L. This result is higher compared to the preliminary test results, probably due to n-octanol soluble chlorine containing impurities of the test item.

Calculation of the partition coefficient log P_OW from the individual solubilities

In the project PS20180221-3 the water solubility of the test item at 20 °C was determined to be < 1.08 mg/L. Within this project the n-octanol solubility of the test item at 20 °C was determined to be 6.5 g/L.

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

log P_OW> 3.8

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.

It was found to be:

log P_OW > 3.8

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.

It was found to be:

log P_OW > 3.8

As the test item is insoluble and organic solvents, no feasible quantification method for the dye itself is available. The measurements are based on the TOC measured in both phases. However, not only the test item but also (more) soluble impurities are included in the TOC measurement. Therefore, the partition coefficient of the test item was calculated with KOWWIN v1.68 included in EpiSuite 4.1.

The partition coefficient of Vat Green 13 was calculated to be log Kow = 11.6.

Key value for chemical safety assessment

Log Kow (Log Pow):

11.6

at the temperature of:

25 °C