[2-[ethyl[3-methyl-4-[(3-phenyl-1,2,4-thiadiazol-5-yl)azo]phenyl]amino]ethyl]trimethylammonium methyl sulphate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

December 15, 2017 - January 12, 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

GLP compliance:

no

Type of method:

flask method

Key result

Water solubility:

53 g/L

Conc. based on:

test mat.

Loading of aqueous phase:

54 g/L

Temp.:

20 °C

pH:

> 2.1 - < 2.2

Preliminary   test

In a stepwise procedure, increasing volumes of demineralized water were added at room temperature to a defined amount of the test item. After each addition of an amount of water the mixture was treated with ultrasound for 10 minutes and visually checked for any undissolved particles.

Table4: Results of the preliminary test

Amount of test item / mg	Added volume of demineralized water / mL	Total volume of demineralized water / mL	Appearance of mixture
105.1	0.1	0.1	not dissolved
	0.4	0.5	not dissolved
	0.5	1.0	not dissolved
	1.0	2	not dissolved
	8.0	10	not dissolved
103.6	100	100	dissolved

The preliminary test showed that the water solubility of the test item is > 10 mg/L. According to the preliminary test the water solubility was determined by the flask method in the main test.

 Flask method

The flask method was performed as described above. The data for the evaluation are given in Table5. After the equilibration time precipitate was observed in the flasks of the experiments excluding in the blank experiment.The water solubility was calculated from the measured and unrounded concentration values and not from the rounded values given in Table5.

Table5: Water solubility experiments of the test item

Experiment	24 h experiment	48 h experiment	72 h experiment	Blank experiment (72 h)
Amount of test item / g	1.34	1.34	1.29	--
Amount of demineralized water / mL	25	25	25	25
Stirring time at 30 °C / h	24	48	72	72
pH at 25 °C	2.1	2.1	2.2	6.6
Aliquot of the flasks / mg[1]	92.95	82.75	92.39	99.67
1^stDilution / g	9.92	9.90	9.94	9.99
Aliquot of the flasks / mL	0.1	0.1	0.1	0.1
2^ndDilution / mL	1	1	1	1
Dilution factor	1067	1196	1076	1002
Measured concentration / mg/L	49.49 / 49.71	45.4 / 45.6	46.7 / 46.7	-- / --
Mean concentration / mg/L	49.60	45.51	46.68	--
Water solubility / g/L	52.9	54.4	50.2	--

The water solubility of the test item at 20 °C was determined to be52.5 g/L (± 2 g/L).

[1]The density of the solution was determined by weighting a 5 mL flask. It was found to be 1.007 g/mL. Therefore the calculation of the dilution factor via weight instead of volume is accepted. It has no effect on the final results.

Executive summary:

The water solubility c_S of the test item at a temperature of 20 °C was determined according to the flask method. It was found to be:

                                                                 c_S = 53 g/L (± 2 g/L)

Description of key information

The water solubility c_S of the test item at a temperature of 20 °C was determined according to the flask method. It was found to be:

                                                                 c_S = 53 g/L (± 2 g/L)

Key value for chemical safety assessment

Water solubility:

53 g/L

at the temperature of:

20 °C