Reaction mass of 2-hydroxyethyl laurate and ethylene dilaurate

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Aug 12 - Dec 01, 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Qualifier:

according to guideline

Guideline:

OECD Guideline 115 (Surface Tension of Aqueous Solutions)

GLP compliance:

yes (incl. QA statement)

Remarks:

The Department of Health of the Government of the United Kingdom

Type of method:

ring method

Surface tension:

>= 36 - <= 58.3 mN/m

Temp.:

20 °C

Conc.:

90 vol%

Results

The readings, times and temperatures for the sample solutions are shown in the following tables:

 

Sample 1

Time (mins)	Reading (mN/m)	Temperature (°C)
67	34.5	20.0
93	36.0	20.0
124	36.0	20.0
148	36.0	20.0
Sampling stopped early due to variability between results of Samples 1 and 2.

Sample 2

Time (mins)	Reading (mN/m)	Temperature (°C)
80	57.5	20.0
110	58.0	20.0
136	58.5	20.0
160	58.5	20.0
Sampling stopped early due to variability between results of Samples 1 and 2.

Sample 3

Time (mins)	Reading (mN/m)	Temperature (°C)
68∗	50.0	20.0
92	50.5	20.0
116	50.5	20.0
144	50.5	20.0
168	50.5	20.0
193	50.5	20.0

Sample 4

Time (mins)	Reading (mN/m)	Temperature (°C)
80∗	37.0	20.0
105∗	37.0	20.0
133	41.0	20.0
157	41.5	20.0
180	41.0	20.0
204	41.0	20.0
229	41.0	20.0

Mean Sample 1 result : 36.0 mN/m pH of Sample 1 : 5.5

Mean Sample 2 result : 58.3 mN/m pH of Sample 2 : 5.0

Mean Sample 3 result : 50.5 mN/m pH of Sample 1 : 5.3

Mean Sample 4 result : 41.1 mN/m pH of Sample 2 : 5.1

Overall result : 36.0 to 58.3 mN/m

Overall temperature : 20.0 ± 0.5 ºC

Discussion

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.

The surface tension measurement assessment was performed on four sample solutions. This was due to the variability in sample measurements. The test item is a laurate ester which has the potential to form micro emulsions in solution. These micro emulsions may form colloidal dispersions at the surface boundary and therefore influence the result. In addition, the ester functionality of the test item is prone to hydrolysis. The hydrolysis may also influence the surface tension results.

Therefore taking all the above into consideration, it was considered more appropriate to quote the surface tension result as a range.

The test item can be considered as surface active.

Conclusion

The surface tension of nominally 90 % saturated solutions of test item in water has been determined to be in the range 36.0 to 58.3 mN/m at 20.0 ± 0.5 °C. The test item was considered to be surface-active.

Conclusions:

The test item can be considered as surface active.

Description of key information

In the range of 36.0 to 58.3 mN/m (90 % saturated solution) at 20.0 ± 0.5 °C, using a ring method (Method A5/OECD115).

The test item can be considered as surface active.