Registration Dossier

Diss Factsheets

Administrative data

Endpoint:
water solubility
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2019
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2019

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
other: EC Guideline A.5. Surface Tension
Version / remarks:
May 31, 2008
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: OECD Guideline 115. Surface Tension of Aqueous Solutions
Version / remarks:
July 27, 1995
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: ISO Guide 4311. Anionic and non-ionic surface active agents – Determination of the critical micellization concentration – Method by measuring surface tension with a plate, stirrup or ring
Version / remarks:
1979
Deviations:
no
Principles of method if other than guideline:
According to document Guidance on the Application of the CLP Criteria:
Surface active substances can form emulsions in which the bioavailability is difficult to ascertain, even with careful preparation of solutions. Micelle formation can result in an overestimation of the bioavailable fraction even when ‘solutions’ are apparently formed. This presents significant problems of interpretation in each of the water solubility, partition coefficient, bioaccumulation and aquatic toxicity studies;
According to document Guidance on information requirements and chemical safety assessment, is prudent to take the CMC as solubility limit.
GLP compliance:
yes
Type of method:
other: OECD harmonized ring method

Test material

Constituent 1
Chemical structure
Reference substance name:
Sodium diisopropylnaphthalenesulphonate
EC Number:
215-343-3
EC Name:
Sodium diisopropylnaphthalenesulphonate
Cas Number:
1322-93-6
Molecular formula:
C16H20O3S.Na
IUPAC Name:
sodium diisopropylnaphthalene-sulfonate
Test material form:
solid: particulate/powder
Details on test material:
white to off-white lumps

Results and discussion

Water solubility
Remarks on result:
other: CMC = 2089 mg/L.
Details on results:
The CMC was determined from the intersection of the two trend lines y1 and y2 (see attached figure). Trendline y1 was obtained using the data of the test solutions with test item concentrations of 201.74, 300.97, 400.00, 503.13, 704.82 and 1203.8 mg/L. Trendline y2 was obtained from the mean surface tension of the test solutions with test item concentrations of 2421.3, 4013.3 and 6990.0 mg/L.
The intersection was calculated to be at a log C value of 3.32. It corresponded with a CMC of 2089 mg/L.

Applicant's summary and conclusion

Conclusions:
According to the Guidance on the Application of the CLP Criteria, for surface active substances the CMC is the most prudent approach to determine the solubility limit.
The CMC of the test item was determined by measuring the surface tension of test item solutions at different test item concentrations.
The Critical Micelle Concentration (CMC) of the test item is 2089 mg/L.