Registration Dossier

Physical & Chemical properties

Water solubility

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From November 08, 2017 to February 07, 2018
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
other: OECD Guideline 115: Surface Tension of Aqueous Solutions
Version / remarks:
27 July 1995
Deviations:
no
Qualifier:
according to
Guideline:
other: EU Method A5: Surface tension
Version / remarks:
30 May 2008
Deviations:
no
Principles of method if other than guideline:
Below the CMC, a surfactant is considered to be thermodynamically soluble in the water; whereas above the CMC, the solubility of a surfactant in water has been exceeded and the excess surfactant aggregates to form micelles. These micelles have significantly less effect on the surface tension of a solution and are considered not to be in solution. Thus, the water solubility of a surfactant may be expressed in terms of the CMC.
GLP compliance:
no
Remarks:
The study was conducted in a facility which operates in accordance with Good Laboratory Practice principles; however no claim of GLP compliance was intended nor is made for this study
Type of method:
other: by determining the surface tension of a range of aqueous sample solutions of differing concentration
Key result
Water solubility:
ca. 24 mg/L
Conc. based on:
test mat.
Incubation duration:
ca. 17.25 h
Temp.:
20 °C
pH:
ca. 5.2
Remarks on result:
other: Water solubility determined as CMC
Details on results:
Please see below table.

Results

The readings and temperatures for the sample solutions are shown in the following table:

Table1: Surface tension values

Concentration (mg/L)

Reading (mN/m)

Temperature (°C)

1.036 x 104

40.0

20.0

40.0

20.0

40.0

20.0

3.109 x 103

42.5

20.0

42.5

20.0

42.5

20.0

1.036 x 103

43.0

20.0

43.0

20.0

43.0

20.0

310.9

44.5

20.0

44.5

20.0

44.5

20.0

103.6

45.0

20.0

45.0

20.0

45.0

20.0

31.09

49.0

20.0

49.0

20.0

49.0

20.0

10.36

53.5

20.0

53.5

20.0

53.5

20.0

6.218

62.0

20.0

62.0

20.0

62.0

20.0

3.109

59.5

20.0

61.5

20.0

63.5

20.0

64.5

20.0

65.0

20.0

66.0

20.0

66.5

20.0

67.5

20.0

67.5

20.0

67.5

20.0

2.072

68.0

20.0

68.0

20.0

69.5

20.0

69.5

20.0

69.5

20.0

1.036

69.0

20.0

71.0

20.0

72.0

20.0

72.0

20.0

72.0

20.0

0.3109

73.0

20.0

73.0

20.0

73.0

20.0

Mean surface tension values were based on the last three readings for a particular concentration which were considered to be constant.

The concentration (mg/L), log10 [concentration (mg/L)] and mean surface tension values for the sample solutions are shown in the following table:

 

Table 2: The concentration (mg/L), log10 [concentration (mg/L)] and mean surface tension values

Concentration
(
mg/L)

Log10Concentration

Mean Surface Tension (mN/m)

Solution pH

1.036 x 104

4.015

40.0

4.03

3.109 x 103

3.493

42.5

4.35

1.036 x 103

3.015

43.0

4.62

310.9

2.493

44.5

4.81

103.6

2.015

45.0

5.01

31.09

1.493

49.0

5.08

10.36

1.015

53.5

5.32

6.218

0.794

62.0

5.51

3.109

0.493

67.5

5.54

2.072

0.316

69.5

5.29

1.036

0.015

72.0

5.66

0.311

-0.507

73.0

5.63

The plot of log10 [concentration (mg/L)] versus surface tension (mN/m) was drafted. For graph, kindly refer the attached background material section.

Line 1 (red) was generated from linear regression of 4 sample solution concentrations for which the surface tension was shown to be concentration dependent and Line 2 (green) was generated from linear regression of 5 sample solution concentrations for which the surface tension was observed to be essentially independent of concentration. The intersection of these two lines gave the critical micelle concentration and was calculated by solving the two equations:

Line 1 equation: y = - 22.4 x + 77.8

Line 2 equation: y = - 2.41 x + 50.2

The sample solution at 31.09 mg/L was not used in generating the two lines. At this concentration the surface tension appeared to be transitioning to Line 2 at a shallower gradient than Line 1. The sample solutions at 1.036 and 0.311 mg/L were not used in generating the two lines. At this concentration the surface tension was only slightly affected and was approaching that of purified water.

The CMC was determined to be 23.9 mg/L.

Conclusions:
Under the study conditions, the the CMC or water solubility of the test substance was determined to be 24 mg/L at 20.0 ± 0.5°C.
Executive summary:

A study was conducted to determine the critical micelle concentration (i.e., CMC, a water solubility equivalent for surfactants) of the test substance, 'iso and anteiso C10-40 AAP EDM-ES' (active: 96%), by measuring the surface tension of a range of aqueous sample solutions of differing concentrations, according to OECD Guideline 115 and EU Method A.5 (Envigo, 2018). Due to the surface activity of the test substance, the CMC value was considered as a water soluibility equivalent in accordance with the ECHA R.7a Guidance. Under the study conditions, the CMC of the test substance was determined to be 24 mg/L at 20 ± 0.5˚C (Envigo, 2018).

Description of key information

The water solubility of the test substance was determined based on critical micelle concentration (a water solubility equivalent of surfactant), according to OECD Guideline 115 and EU Method A.5 (Envigo, 2018).

Key value for chemical safety assessment

Water solubility:
24 mg/L
at the temperature of:
20 °C

Additional information

(based on CMC)