Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Justification for type of information:

The study was well conducted and critical micelle concentration (CMC) method was used as an alternative to the water solubility as more relevant for surface active substances.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

no guideline available

Principles of method if other than guideline:

For surface active substances the critical micelle concentration (CMC) method is used as an alternative to the water solubility. The CMC is determined by measuring the surface tension of test substance solutions at different test substance 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. The CMC is determined from a plot of the surface tension versus the logarithm of the test substance concentration.

GLP compliance:

yes

Type of method:

other: CMC evaluation based on surface tension measurements

Test material

Test material information

Constituent 1

Reference substance name:

Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

EC Number:

247-556-2

EC Name:

Dodecylbenzenesulphonic acid, compound with isopropylamine (1:1)

Cas Number:

26264-05-1

Molecular formula:

C18H30O3S.C3H9N

IUPAC Name:

sodium dodecylbenzenesulfonate

Test material form:

liquid

Results and discussion

Water solubility

Water solubility:

4 187 mg/L

Conc. based on:

other: CMC

Temp.:

20 °C

Remarks on result:

other: pH: not determined Incubation duration: detailed as overnight Loading rate: 2000 to 20000 mg/L

Details on results:

Preliminary data:
According to the preliminary data, an estimated critical micelle concentration of >10000 mg/L was obtained.

Main study:
The CMC was determined from the intersection of the two trend lines y1 and y2. Trendline y1 was obtained using the data of the test solutions with test item concentrations of 10.1, 100.1, 2008.3 and 5040.8 mg/L. Trendline y2 was obtained from the mean surface tension of the test solutions with test item concentrations of 9976.6, 12000, 14956 and 20097 mg/L.

The intersection was calculated to be at a log C value of 3.62. It corresponded with a CMC of 4187 mg/L.

The water solubility value based on a visual assessment was > 20000 mg/L.

Applicant's summary and conclusion

Conclusions:

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 substance is 4187 mg/L.