Lithium isooctadecanoate

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

Deviations:

yes

Remarks:

See Details on methods

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

yes

Remarks:

See Details on methods

GLP compliance:

yes (incl. QA statement)

Type of method:

ring method

Specific details on test material used for the study:

- Stability under test conditions: Stable
- Treatment of test material prior to testing: None
- Preliminary purification step: None
- Final preparation of a solid: Applied neat

Surface tension:

ca. 39.5 mN/m

Temp.:

20 °C

Conc.:

0.003 g/L

Remarks on result:

other: The test was conducted on aqueous solutions of test item prepared at 90% saturation concentration

Table 1. Readings, times and temperatures for the sample solutions

Sample	Time (mins)	Reading (mN/m)	Temperature (°C)
1	90	40	20
1	139	40	20
1	168	40	20
1	192	40	20
1	209	40	20
1	299	40	20
1	Mean	40	20
2	100	39	20
2	157	38.5	20
2	177	39	20
2	200	39	20
2	302	39	20
2	Mean	38.9	20
1 and 2	Mean	39.5	20

According to criteria mentioned in EC Method A.5, substances showing a surface tension lower than 60 mN/m under the conditions of this method should be regarded as being surface active.

On completion of the static re-equilibration of the saturated sample solutions at 20°C, the solutions were observed as translucent due to a dispersion of excess, undissolved test item. However this dispersion could not be removed by centrifugation, similar to issues encountered during attempted determination of the water solubility, such that the final surface tension sample solutions also remained translucent with this dispersion. The presence of this dispersion was not considered to impact on the validity of the determination on the basis of these dispersion characteristics of the test item replicated expected behaviour on accidental environmental release. In addition, although the presence of the dispersion indicated that the sample solution/dispersion concentrations were at a concentration above that of the critical micelle concentration of the test item, above this concentration, any increasing concentration of dispersed material has only a limited influence on the overall surface tension of the sample.

The mean surface tension of duplicate aqueous solutions of test item prepared at 90% saturation concentration has been determined to be 39.5 mN/m at 20.0 ± 0.5°C. The test item was considered to be surface-active.

Conclusions:

The mean surface tension of duplicate aqueous solutions of lithium isooctadecanoate prepared at 90% saturation concentration has been determined to be 39.5 mN/m at 20.0 ± 0.5 °C. The test item was considered to be surface-active.

Executive summary:

The surface tension of lithium isooctadecanoate was conducted in a GLP-compliant ring balance test following OECD guideline 115 (Envigo 2017). The study deviated from the guideline because the test item formed stable dispersions from which the undissolved test item could not be removed. These were not considered to have affected the integrity of the study. The study is considered to be relevant and reliable for use for this endpoint. Lithium isooctadecanoate has a surface tension below 60 mN/m and is therefore regarded as being surface active. This is consistent with the observed characteristics of lithium isooctadecanoate in water and its structure, which is representative of the "soap" surfactant class.

Description of key information

The surface tension of duplicate 90% saturated aqueous solutions of lithium isooctadecanoate has been determined to be 39.5 mN/m at 20.0 ± 0.5°C.

Key value for chemical safety assessment

Surface tension:

39.5

Additional information

The surface tension of lithium isooctadecanoate was determined in a GLP-compliant ring balance test following OECD guideline 115 (Envigo 2017). The study deviated from the guideline because the test item formed stable dispersions from which the undissolved test item could not be removed. These were not considered to have affected the integrity of the study. The study is considered to be relevant and reliable for use for this endpoint. Lithium isooctadecanoate has a surface tension below 60 mN/m and is therefore regarded as being surface active. This is consistent with the observed characteristics of lithium isooctadecanoate in water and its structure, which is representative of the "soap" surfactant class.