Reaction product of 3,9-dibromobenzanthrone condensed with 2 equivalents of 1-aminoanthraquinone, subsequently further condensed under oxidative conditions

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April 17, 2015 - April 24, 2015

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Key result

Water solubility:

< 1 other: mg (TOC) /L

Conc. based on:

not specified

Temp.:

20 °C

pH:

6

 Individual results

 Preliminary visual estimation of the water solubility

Different amounts of the test item were stirred 100 mL and 500 ml distilled water, respectively and the mixtures were visually checked for any undissolved parts.Table 2 shows the results from the preliminary test.

 Table 2: Appearance of the test mixtures

Amount of test item in mg	Total volume in ml	Appearance of mixture
12.6	100	undissolved^1)
11.7	500	undissolved^1)
2.4	500	undissolved^1)

¹⁾: After adding the indicated amount of water, the solution was stirred for approx. 72 h.

The preliminary visual experiments showed that the solubility of the test item in water is below 5 mg/l(without correction for the purity). As the test item is insoluble in organic solvents it is impossible to coat the sea sand of the columns with the test item. For this reason the column elution method is not applicable and the water solubility had to be determined by the flask method.

Results of the flask method

The flask method was performed After the equilibration time precipitate was observed in the flasks of the experiments. No particles were seen in the blank experiment.As the test substance was neither soluble in water nor in organic solvents,the concentration of the test item dissolved in water was determined by measurement of the dissolved TOC.The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given inTable3.

Table3:Solubility of the test item in water – experiments A to D

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item (mg)	5.4	5.4	5.6	--
Amount of distilled water (ml)	200	200	200	200
Stirring time at 30 °C (h)	24	48	72	72
pH at 23°C	5.9	6.1	6.2
Measured TOC concentration (mg C/l)	< 0.51	< 0.51	< 0.51

 

The TOC concentration in the aqueous samples was determined to be < 1 mg/l TOC.

Conclusions:

The water solubility of the test item was determined at a temperature of 20 °C according to OECD 105. Due to its insolubility in aqueous and organic solvents, it is not possible to analytically quantify Vat Black 25. Hence, the total organic carbon content (TOC) was measured. It was determined to be: < 1 mg (TOC) / L.

Executive summary:

Study performed to determine the water solubility of the test substance using the flask method.

 

Study performed in accordance with the following guidelines:

EU Method A.6 (Water Solubility)

OECD Guideline 105 (Water Solubility)

 

In a simple preliminary test, mixtures of water and test item are prepared and visual assessed. The approximate water solubility of the test item, resulting from the preliminary test, indicates which of the two methods for the determination of the water solubility is applicable. Whereas the column elution method covers solubilities below 10 mg/L the flask method is suitable for solubilities above 10 mg/L.

Additionally, the results of the preliminary test provide information of the appropriate amount of test item to be used in the main test.

 

Flask method

The quantity of test item necessary to saturate the desired volume of water is estimated from the preliminary test. About five times that quantity is weighed into each of three glass vessels fitted with glass stoppers. The batches are stirred for different times at 30 °C (24 h experiment, 48 h experiment, 72 h experiment) in tightly closed flasks. A blank sample consisting of water only is stirred for 72 h at 30°. After equilibration (further stirring for 24 h at 20 °C), the suspensions and the blank are taken and prepared for the analytical determination. The pH values of the saturated solutions are determined.

 

Results

Preliminary visual estimation of the water solubility

Different amounts of the test item were stirred 100 mL and 500 ml distilled water, respectively and the mixtures were visually checked for any undissolved parts.

The preliminary visual experiments showed that the solubility of the test item in water is below 5 mg/l(without correction for the purity). As the test item is insoluble in organic solvents it is impossible to coat the sea sand of the columns with the test item. For this reason the column elution method is not applicable and the water solubility had to be determined by the flask method.

 

Results of the flask method

The flask method was performed. After the equilibration time precipitate was observed in the flasks of the experiments. No particles were seen in the blank experiment. As the test substance was neither soluble in water nor in organic solvents, the concentration of the test item dissolved in water was determined by measurement of the dissolved TOC.

The TOC concentration in the aqueous samples was determined to be < 1 mg/l TOC.

 

The water solubility of the test item was determined at a temperature of 20 °C according to OECD 105. Due to its insolubility in aqueous and organic solvents, it is not possible to analytically quantify Vat Black 25. Hence, the total organic carbon content (TOC) was measured. It was determined to be: < 1 mg (TOC) / L.

Description of key information

Key value determined in a laboratory test using the flask method, performed in accordance with OECD Guideline 105 and EU Method A.6.

 

The water solubility of the test item was determined at a temperature of 20 °C according to OECD 105. Due to its insolubility in aqueous and organic solvents, it is not possible to analytically quantify Vat Black 25. Hence, the total organic carbon content (TOC) was measured. It was determined to be: < 1 mg (TOC) / L.

Key value for chemical safety assessment

Water solubility:

1 mg/L

at the temperature of:

20 °C

Additional information

The water solubility of the test item was determined at a temperature of 20 °C according to OECD 105. Due to its insolubility in aqueous and organic solvents, it is not possible to analytically quantify Vat Black 25. Hence, the total organic carbon content (TOC) was measured. It was determined to be: < 1 mg (TOC) / L.