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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:
26-11-2014 to 03-03-2015
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
Water solubility:
8.5 g/L
Conc. based on:
other: water solubility of the trans-isomer
Incubation duration:
>= 24 - <= 72 h
Temp.:
20 °C
pH:
3.3
Water solubility:
27.2 g/L
Conc. based on:
other: water solubility of the cis-isomer
Incubation duration:
>= 24 - <= 72 h
Temp.:
20 °C
pH:
3.3
Key result
Water solubility:
35.8 g/L
Conc. based on:
other: mean water solubility of cis- and trans- isomers
Incubation duration:
>= 24 - <= 72 h
Temp.:
20 °C
pH:
3.3

Preliminary visual estimation of the water solubility

In a stepwise procedure, increasing volumes of distilled 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.

Table 1: Results of the preliminary estimation of the water solubility

Amount of test
item / mg

Added volume of
dist. water / mL

Total volume / mL

Appearance of mixture

108.7

0 1

0.1

undissolved

0.4

0.5

undissolved

0.5

1.0

undissolved

1.0

2

undissolved

8.0

10

dissolved*

* After treating the mixture for 10 minutes with ultrasound the formation of small drops was observed, but the next day these drops were dissolved.

According to the preliminary visual estimation the water solubility of the test item was between 10.9 g/L and 54.4 g/L. Therefore, in the main test the water solubility was determined by the flask method.

Main test - Flask method

After the equilibration time a two phase system was observed in the experiments A to C. The upper aqueous phase was taken and the samples for the HPLC analysis were prepared. The test item consisted of a cis- and trans-isomer. The water solubility was calculated from the measured and unrounded concentration values.

Table 2: Water solubility of the test item, Peak 1 (trans-isomer)

Experiment

24 h
experiment

48 h
experiment

72 h
experiment

Blank experiment
(72 h)

Amount of test item / g
(cis- and trans-isomer)

13.65

13.62

13.63

-

Amount of distilled water / mL

50

50

50

50

Stirring time at 30 °C / h

24

48

72

72

pH at 23 °C

3.3

3.3

3.2

5.8

Aliquot of the flasks / mL

0.1

0.1

0.1

0.1

Dilution to volume / mL

50

50

50

50

Dilution factor

500

500

500

500

Measured concentration / mg/L

17.14 / 17.16

17.19 / 17.15

16.87 / 17.02

- / -

Mean concentration / mg/L

17.15

17.17

16.95

-

Water solubility / g/L

8.58

8.58

8.47

-

The water solubility of the test item peak 1 (trans-isomer) at 20 °C was determined to be 8.5 g/L (± 0.1 g/L).

Table 3: Water solubility of the test item. Peak 2 (cis-isomer)

Experiment

24 h
experiment

48 h
experiment

72 h
experiment

Blank experiment
(72 h)

Amount of test item / g
(cis- and trans-isomer)

13.65

13.62

13.63

-

Amount of distilled water / mL

50

50

50

50

Stirring time at 30 °C / h

24

48

72

72

pH at 23 °C

3.3

3.3

3.2

58

Aliquot of the flasks / mL

0.1

0.1

0.1

0.1

Dilution to volume / mL

50

50

50

50

Dilution factor

500

500

500

500

Measured concentration / mg/L

54.70 / 54.89

53.91 / 53.87

54.84 / 54.54

-/-

Mean concentration / mg/L

54.80

53.89

54.69

-

Water solubility / g/L

27.40

26.95

27.34

-

The water solubility of the test item peak 2 (cis-isomer) at 20 °C was determined to be 27.2 g/L (± 0.3 g/L).

The mean water solubility at 20 °C of the test item including the trans-isomer and the cis-isomer was determined to be 35.8 g/L.

Conclusions:
The water solubility cs of the test item was determined at a temperature of 20 °C. The test item consists of a cis- and trans-isomer. The water solubility of the cis- and trans-isomer was determined separately. It was found to be:
cs (trans) = 8.5 g/L (± 0.1 g/L)
cs (cis) = 27.2 g/L (± 0.3 g/L).
The mean water solubility at 20 °C of the test item including the trans- and the cis-isomer was determined to be: cs (total) = 35.8 g/L.
Executive summary:

The water solubility of the test item was determined according to OECD 105 and Regulation (EC) No. 440/2008 method A.6 using the shake flask method with HPLC analysis. About 14 mg test item were weighed into 100 mL stoppered Erlenmeyer flasks (nine parallels) according to the estimated solubility based on the Preliminary Test. After the addition of 50 mL distilled water, the flasks were stirred at 30 °C. After one day, three of the vessels were removed and re-equilibrated at 20 °C for 24 hours. The content of the vessel was then centrifuged at 20 °C and the concentration in the clear aqueous phase was determined by HPLC. The other flasks were treated similarly after initial equilibration at 30 °C for two and three days, respectively. The samples were diluted before the analysis (two parallel dilutions). The pH of each sample was recorded. The test item consists of a cis- and trans-isomer. The water solubility of the cis- and trans-isomer was determined separately. It was found to be:

cs (trans) = 8.5 g/L (± 0.1 g/L)

cs (cis) = 27.2 g/L (± 0.3 g/L).

The mean water solubility at 20 °C of the test item including the trans- and the cis-isomer was determined to be: cs (total) = 35.8 g/L at 20 °C (pH = 3.3).

Description of key information

The water solubility cs of the test item was determined at a temperature of 20 °C. The test item consists of a cis- and trans-isomer. The water solubility of the cis- and trans-isomer was determined separately. It was found to be:

cs (trans) = 8.5 g/L (± 0.1 g/L)

cs (cis) = 27.2 g/L (± 0.3 g/L).

The mean water solubility at 20 °C of the test item including the trans- and the cis-isomer was determined to be: cs (total) = 35.8 g/L.

Key value for chemical safety assessment

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

Additional information

The water solubility of the test item was determined according to OECD 105 and Regulation (EC) No. 440/2008 method A.6 using the shake flask method with HPLC analysis. About 14 mg test item were weighed into 100 mL stoppered Erlenmeyer flasks (nine parallels) according to the estimated solubility based on the Preliminary Test. After the addition of 50 mL distilled water, the flasks were stirred at 30 °C. After one day, three of the vessels were removed and re-equilibrated at 20 °C for 24 hours. The content of the vessel was then centrifuged at 20 °C and the concentration in the clear aqueous phase was determined by HPLC. The other flasks were treated similarly after initial equilibration at 30 °C for two and three days, respectively. The samples were diluted before the analysis (two parallel dilutions). The pH of each sample was recorded. The test item consists of a cis- and trans-isomer. The water solubility of the cis- and trans-isomer was determined separately. It was found to be:

cs (trans) = 8.5 g/L (± 0.1 g/L)

cs (cis) = 27.2 g/L (± 0.3 g/L).

The mean water solubility at 20 °C of the test item including the trans- and the cis-isomer was determined to be: cs (total) = 35.8 g/L at 20 °C (pH = 3.3) (reference 4.8-1).