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Physical & Chemical properties

Water solubility

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Reference
Endpoint:
water solubility
Remarks:
Critical Micelle Concentration (CMC)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
To be completed
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
other: OECD Guideline 115. Surface Tension of Aqueous Solutions. July 27, 1995.
Principles of method if other than guideline:
The Critical Micelle Concentration (CMC) was determined by measuring the surface tension of test item solutions at different test item concentrations. For surface active substances which form micelles in solution, the surface tension decreases with increasing concentration until the CMC is reached. At concentrations above the CMC, the surface tension remains constant.
GLP compliance:
yes (incl. certificate)
Type of method:
other: OECD harmonized ring method
Specific details on test material used for the study:
- Test material: REACH substance = freeze-dried commercial product
- Analytical purity: 97.2%
- Purity test date: 08 March 2017
- Lot:bacth No.: WI6G16X07 after drying
- Expiration date of the lot/batch: 16 July 2018
- Appearance: Off-white to yellow crystals
- Storage: At room temperature
Key result
Water solubility:
1 463 mg/L
Conc. based on:
test mat.
Remarks on result:
other: Critical Micelle Concentration (CMC)

Table 1:      
Surface Tension of the 52 mg/L Test Item Solution

Measurement

Time passed after transfer test solution to test vessel
[minutes]

Surface tension
(mN/m)

 

 

individual

mean

mean multiplied by
Φband Harkins-Jordan corrected value

1

41

54.5

52.71

53.1

2

42

53.3

 

 

3

43

52.6

 

 

4

44

52.9

 

 

5

45

52.6

 

 

6

46

52.5

 

 

7

47

52.8

 

 

1         Mean calculated from measurements 3 to 7, after equilibrium was reached.

 


 

Table 11        
Surface Tension of the 208 mg/L Test Item Solution

Measurement

Time passed after transfer test solution to test vessel
[minutes]

Surface tension
(mN/m)

individual

mean

mean multiplied by
Φband Harkins-Jordan corrected value

1

20

41.1

41.51

41.0

2

21

41.3

 

 

3

22

41.6

 

 

4

23

41.7

 

 

5

24

41.5

 

 

6

25

41.6

 

 

1         Mean calculated from measurements 2 to 6, after equilibrium was reached.

 

Table 2        
Surface Tension of the 515 mg/L Test Item Solution

Measurement

Time passed after transfer test solution to test vessel
[minutes]

Surface tension
(mN/m)

 

 

individual

mean

mean multiplied by
Φband Harkins-Jordan corrected value

1

31

33.8

34.1

33.2

2

32

34.1

 

 

3

33

34.1

 

 

4

34

34.2

 

 

5

35

34.2

 

 

 

Table 3:     
Surface Tension of the 5057 mg/L Test Item Solution

Measurement

Time passed after transfer test solution to test vessel
[minutes]

Surface tension
(mN/m)

 

 

individual

mean

mean multiplied by
Φband Harkins-Jordan corrected value

1

15

26.8

25.61

24.5

2

16

25.7

 

 

3

17

25.7

 

 

4

18

25.6

 

 

5

19

25.4

 

 

6

20

25.5

 

 

1         Mean calculated from measurements 2 to 6, after equilibrium was reached.

 

Table 4:    
Surface Tension of the 7163 mg/L Test Item Solution

Measurement

Time passed after transfer test solution to test vessel
[minutes]

Surface tension
(mN/m)

 

 

individual

mean

mean multiplied by
Φband Harkins-Jordan corrected value

1

42

25.1

25.0

23.9

2

43

25.0

 

 

3

44

25.0

 

 

4

45

25.0

 

 

5

46

25.0

 

 

 

Table 5:    
Surface Tension of the 12357 mg/L Test Item Solution

Measurement

Time passed after transfer test solution to test vessel
[minutes]

Surface tension
(mN/m)

 

 

individual

mean

mean multiplied by
Φband Harkins-Jordan corrected value

1

15

25.4

25.1

24.0

2

16

25.1

 

 

3

17

25.1

 

 

4

18

25.0

 

 

5

19

25.0

 

 

 

Table 6 :       
Surface Tension of the 20327 mg/L Test Item Solution

Measurement

Time passed after transfer test solution to test vessel
[minutes]

Surface tension
(mN/m)

 

 

individual

mean

mean multiplied by
Φband Harkins-Jordan corrected value

1

15

25.0

25.0

23.9

2

16

25.0

 

 

3

17

25.0

 

 

4

18

25.0

 

 

5

19

25.1

 

 

 

The results in Table 1 toTable 6 were used for a accurate calculation of the log C value. The CMC was determined from the intersection of the two trend lines y1and y2. Trendline y1was obtained using the data of the test solutions with test item concentrations of 52, 208 and 515 mg/L. Trendline y2was obtained from the mean surface tension of the test solutions with test item concentrations of 5057, 7163, 12357 and 20327 mg/L. The intersection was calculated to be at a log C value of 3.17. It corresponded with a CMC of 1463 mg/L.

Conclusions:
The Critical Micelle Concentration (CMC) of the test item was 1463 mg/L.
Executive summary:

The Critical Micelle Concentration (CMC) of the test item (= REACH substance) was determined in a GLP-compliant study performed in accordance with OECD Guideline No. 115, by measuring the surface tension of test item solutions at different test item concentrations. The Critical Micelle Concentration (CMC) of the test item was 1463 mg/L.

Description of key information

The Critical Micelle Concentration (CMC) of the test item (= REACH substance) was determined in a GLP-compliant study performed in accordance with OECD Guideline No. 115, by measuring the surface tension of test item solutions at different test item concentrations; the Critical Micelle Concentration (CMC) of the test item was 1463 mg/L. The solubility in water of the test item was otherwise determined in a GLP-compliant study performed in accordance with EC A.8 method and OECD Guideline No. 105, by means of visual observations; the water solubility of the test item was > 1000 mg/L.

In accordance with ECHA's "Guidance on Information Requirements and Chemical Safety Assessment - Chapter R.7a: Endpoint specific guidance" (v6.0, July 2017), the CMC was taken as a solubility limit in water as the test item proved to be surface-active.

Key value for chemical safety assessment

Water solubility:
1 463 mg/L

Additional information

The Critical Micelle Concentration (CMC) of the test item was determined in one GLP-compliant study performed in accordance with standard methods, without deviations; that study is considered as reliable (Klimisch 1) and is selected as a key study for the endpoint. The solubility in water of the test item was otherwise determined in one GLP-compliant study performed in accordance with standard methods, without deviations; that study is considered as reliable (Klimisch 1) but is not selected as a key study for the endpoint considering the surface-active properties of the test item.