Quaternary ammonium compounds, C12-14 (even numbered) alkyl(hydroxyethyl)dimethyl, C12 alkylbis(hydroxyethyl)methyl, chlorides and amines, C12-14 (even numbered) alkyldimethyl, chlorides

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 July 2018

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:

no

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

plate method

Key result

Surface tension:

ca. 45.97 mN/m

Temp.:

20.5 °C

Conc.:

1 g/L

Key result

Surface tension:

ca. 39.43 mN/m

Temp.:

19.9 °C

Conc.:

1 g/L

Key result

Surface tension:

ca. 39.79 mN/m

Temp.:

20.2 °C

Conc.:

1 g/L

Results

Measured Values Negative Control

Measurement	Time	Mass	Surface Tension	Temperature
No	s	g	mN/m	°C
1	4.2	0.2986	72.84	21.2
2	5.1	0.2982	72.74	21.2
3	6.1	0.2981	72.72	21.2
4	7.1	0.2981	72.72	21.2
5	8.1	0.2980	72.70	21.2
6	9.1	0.2977	72.62	21.2
7	10.1	0.2982	72.74	21.2
8	11.1	0.2980	72.70	21.2
9	12.1	0.2981	72.72	21.2
10	13.1	0.2982	72.74	21.2
Mean			72.73
Standard Deviation			0.05

 

Main Test

The test substance solution was held at constant temperature (20.0 ± 0.5 °C). 56 minutes after conclusion of the first measurement series, a second measurement series was performed for verification purposes. The following values were recorded:

 

Measured Values Test Substance First Series

Measurement	Time	Mass	Surface Tension	Temperature
No	s	g	mN/m	°C
1	4.2	0.1942	47.37	20.5
2	5.1	0.1923	46.91	20.5
3	6.2	0.1908	46.54	20.5
4	7.1	0.1888	46.06	20.5
5	8.2	0.1878	45.81	20.5
6	9.1	0.1873	45.69	20.5
7	10.1	0.1864	45.47	20.5
8	11.1	0.1861	45.40	20.5
9	12.2	0.1854	45.23	20.5
10	13.1	0.1854	45.23	20.5
Mean			45.97
Standard Deviation			0.74

 

Measured Values Test Substance Second Series

Measurement	Time	Mass	Surface Tension	Temperature
No	s	g	mN/m	°C
1	4.2	0.1668	40.69	19.9
2	5.1	0.1647	40.18	19.9
3	6.1	0.1637	39.93	19.9
4	7.1	0.1626	39.67	19.9
5	8.1	0.1611	39.30	19.9
6	9.1	0.1604	39.13	19.9
7	10.1	0.1600	39.03	19.9
8	11.1	0.1600	39.03	19.9
9	12.1	0.1587	38.71	19.9
10	13.1	0.1585	38.67	19.9
Mean			39.43
Standard Deviation			0.66

After the first and the second measurement series, the difference between mean values was 14.23 %. Therefore an additional measurement series was required.

 

Measured Values Test Substance Third Series

Measurement	Time	Mass	Surface Tension	Temperature
No	s	g	mN/m	°C
1	4.2	0.1689	41.20	20.2
2	5.1	0.1668	40.69	20.2
3	6.1	0.1644	40.10	20.2
4	7.1	0.1637	39.93	20.2
5	8.1	0.1627	39.69	20.2
6	9.1	0.1622	39.57	20.2
7	10.1	0.1617	39.45	20.2
8	11.1	0.1609	39.25	20.2
9	12.1	0.1601	39.06	20.2
10	13.1	0.1599	39.01	20.2
Mean			39.79
Standard Deviation			0.71

The mean value of the second and the third measurement series differed by 0.91 % therefore it was considered that the plateau was reached.

 

Result Test Substance

Over a period of two hours, changes in the surface tension were detected. In dependence on time and temperature, values between 38.67 and 47.37 mN/m were recorded. After the third measurement, no significant changes were observed. As the determined surface tension of test substance at the plateau was lower than 60 mN/m, the test substance must be classified as surface active.

 

Validity

The surface tension of water at the measuring temperature was calculated using the following equation:

s = B r^µ (1 + br)

with:

s         surface tension in mN/m

B         Constant 235.8 mN/m

r          1 – T / Tc

T         absolute Temperature in K

Tc        critical Temperature 647.096 K

µ         Constant 1.256

b         Constant -0.625

 

The constants result from the graph of the equation of function in temperature dependence of the surface tension of water. The calculated value for the surface tension of water at 21.2 °C was 72.55 mN/m. The surface tension of the negative control was determined with 72.73 mN/m at 21.2 °C, therefore showing a difference of 0.24 % from the calculated value. The difference lies within the accepted range of 1% deviation from the calculated value.

 

Discussion

The surface tension of the negative control was determined with a difference of 0.24 % from the calculated value. Therefore, the instrument was suitable. The values of the single determinations of the aqueous solution of the test substance showed a significant difference (> 5%) at the repetition measurement series after one hour. Therefore, a third experiment was conducted after two hours. The difference to the second series was only 0.91 % therefore the plateau was reached. All measured values lay below the threshold for surface tension which is stated in the guidelines. Therefore, the result of the test is considered valid and the test substance is classified as “surface active” in a concentration of 1.00 g/L.

Conclusions:

Under the study conditions, the surface tension of the test substance was determined to be in range of 39.43 to 45.97 mN/m.

Executive summary:

A study was conducted to determine the surface tension of the test substance, C12-14 HEDMAC (39.6% active) using tensionmeter, according to the OECD Guideline 115 and EU Method A.5, in compliance with GLP. The surface tension of an aqueous solution of 1 g/L test substance was determined as 39.43 ± 0.66 mN/m at 19.9 °C. The values of the single determinations of the aqueous solution of the test substance showed a significant difference (> 5%) at the repetition measurement series after one hour. Therefore, a third experiment was conducted after two hours. The difference to the second series was only 0.91 % therefore the plateau was reached. As these values were below 60 mN/m, test substance was classified as surface active. The surface tension of the negative control lay within the accepted range. Under the study conditions, the surface tension of the test substance was determined to be in range of 39.43 to 45.97 mN/m, at 1 g/L concentration (Muckle, 2019).

Description of key information

The surface tension of the test substance (39.6% active) was determined using tensiometer according to OECD Guideline 115 and EU Method A.5 (Muckle, 2019)

Key value for chemical safety assessment

Surface tension:

39.43

in mN/m at 20°C and concentration in mg/L:

1 000

Additional information

(39.43 to 45.97 mN/m)