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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
August 09, 2017 - August 31, 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 105 (Water Solubility)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method A.6 (Water Solubility)
Deviations:
no
GLP compliance:
no
Type of method:
flask method
Key result
Water solubility:
71.1 g/L
Conc. based on:
test mat.
Loading of aqueous phase:
139 g/L
Incubation duration:
72 h
Temp.:
30 °C
pH:
7
Key result
Water solubility:
74.6 g/L
Conc. based on:
test mat.
Loading of aqueous phase:
139.4 g/L
Incubation duration:
96 h
Temp.:
30 °C
pH:
7.3
Key result
Water solubility:
36.1 g/L
Conc. based on:
test mat.
Loading of aqueous phase:
139.4 g/L
Incubation duration:
120 h
Temp.:
30 °C
pH:
7.2

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 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

100.6

0.1

0.1

not dissolved

0.4

0.5

not dissolved

0.5

1.0

dissolved

As the water solubility determined in the preliminary test was very high, an additional stirring test was performed to determine the highest amount of test item that can still be stirred sufficiently in a mixture with water.

Table5: Results of the stirring test

Amount of test item

[g]

Added volume of demin. water

[ml]

Total volume

[ml]

Observation

10.1

10

10

could not be stirred

2.5

12.5

could not be stirred

2.5

15.0

could not be stirred

5.0

20.0

could not be stirred *

12.0

50.0

50.0

could not be stirred *

Remark: *      The mixtures could be stirred after the addition of water to the test item, but then

the test item swelled in the water and stirring was not possible any more.

Therefore a concentration of about 140 g/L was used in the main test.

 Flask method

Except of prolonged stirring times, the flask method was performed as described above. The data for the evaluation are given in Table6. 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 Table6.

Table6: Water solubility experiments of the test item

Experiment

72 h experiment

96 h experiment

120 h experiment

Blank

experiment (120 h)

Amount of test item / g

6.95

6.97

6.97

--

Amount of demineralized water / ml

50

50

50

50

Stirring time at 30 °C / h

72

96

120

120

pH at 22 – 24 °C

7.0

7.3

7.2

6.0

Dilution factor

10000

10000

10000

10000

Measured concentration / mg/L

7.11 / 7.11

7.45 / 7.47

3.59 / 3.63

-- / --

Mean concentration / mg/L

7.11

7.46

3.61

--

Water solubility / g/L

71.1

74.6

36.1

--

The water solubilities values of the experiments with 72 h and 96 h stirring times are in agreement. In contrast the experiment with stirring times of 120 h showed a significant lower water solubility. As a conservative approach the highest value of the water solubilities was stated. The water solubility of the test item at 20 °C was determined to be approximately 74.6 g/L without correction of the purity.

Executive summary:

The water solubility cS of the test item Basic Red 29 at a temperature of 20 °C was determined according to the flask method. It was found to be without correction of the purity:

                                                                 cS = 75 g/L

Description of key information

The water solubility cS of the test item Basic Red 29 at a temperature of 20 °C was determined according to the flask method. It was found to be without correction of the purity:

                                                                 cS = 75 g/L

Key value for chemical safety assessment

Water solubility:
75 g/L
at the temperature of:
20 °C

Additional information