2-ethylhexanoic acid, copper salt

Surface tension

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2013-05-21 to 2013-05-28

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)

Remarks:

signed 2010-10-20

Type of method:

OECD harmonised ring method

Surface tension:

52.53 mN/m

Temp.:

20 °C

Conc.:

90 other: solution of Fatty acids, C6-19-branched, zinc salts

Remarks on result:

other: standard deviation of 0.04 mN/m

Determination of the density

The density of the 90 % saturated aqueous solution of Fatty acids,C6-19-branched, zinc salts in double-distilled water was determined in a preliminary measurement to be 1.035 g/cm³ (20.2 °C).

Temperature

The temperature range of the test solution during the whole measurements was 20.1 - 20.2 °C

The room temperature during these measurements was 19.8 - 20.5 °C

Time line of the study

After transfer of the test solution into the test vessel 36.9 minutes were needed to reach equilibrium at which 10 successive measurements with a standard deviation of 0.04 mN/m were possible.

Surface tension of a 90 % saturated aqueous solution of Fatty acids,C6-19-branched, zinc salts

The determination was carried out in ten successive measurements with a standard deviation ≤ 0.05 mN/m.  

Measurement no.*	Time** [min]	Surface tension*** [mN/m]	Temperature * [°C]
1	30.7	52.60	20.1
2	31.4	52.59	20.1
3	32.1	52.56	20.2
4	32.8	52.53	20.1
5	33.5	52.52	20.1
6	34.2	52.53	20.1
7	34.8	52.48	20.2
8	35.5	52.48	20.1
9	36.2	52.49	20.2
10	36.9	52.47	20.1
MV	-	52.53	20.1
SD	-	0.04	0.05

MV = mean value

SD = standard deviation
*) of the last 10 measurements

**) Time from transfer of the test solution into the test vessel until end of each measurement

***) Values already corrected acc. to Harkins & Jordan

Validation

The surface tension of the reference item hexane was determined on 2012-07-16 as 18.33 ± 0.02 mN/m (20 °C) for the Ring Nr. 1, RI 21. This value is in the range of tolerance of ± 1 mN/m acc. to the literature value of 18.42 mN/m at 20 °C.

Conclusions:

The surface tension of a 90 % saturated aqueous solution of Fatty acids, C6-19-branched, zinc salts at 20 °C was determined to be 52.53 mN/m (standard deviation 0.04 mN/m).
Due to the fact that the surface tension is < 60 mN/m, the test item is classified as surface-active substance.

Reference 2

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2013-05-21 to 2013-05-22

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)

Remarks:

signed 2010-10-20

Type of method:

OECD harmonised ring method

Surface tension:

60.22 mN/m

Temp.:

20 °C

Conc.:

1 g/L

Remarks on result:

other: standard deviation of 0.04 mN/m

Determination of the density

The density of the1 g/L aqueoussolution of calcium bis(2-ethylhexanoate) in double-distilled water was determined in a preliminary measurement to be 1.008 g/cm³ (20.2 °C).

Temperature

The temperature range of the test solution during the whole measurements was 19.9 - 20.2 °C

The room temperature during these measurements was 19.8 - 20.1 °C

Time line of the study

After transfer of the test solution into the test vessel 54.0 minutes were needed to reach equilibrium at which 10 successive measurements with a standard deviation of 0.04 mN/m were possible.

Surface tension of a of a 1 g/L aqueous solution of calcium bis(2-ethylhexanoate)

The determination was carried out in ten successive measurements with a standard deviation ≤ 0.05 mN/m.  

Measurement no.*	Time** [min]	Surface tension*** [mN/m]	Temperature * [°C]
1	47.3	60.30	19.9
2	48.1	60.26	20.0
3	48.8	60.23	20.0
4	49.6	60.27	20.0
5	50.3	60.16	19.9
6	51.1	60.21	20.0
7	51.8	60.19	20.0
8	52.6	60.19	20.0
9	53.3	60.21	19.9
10	54.0	60.18	19.9
MV	-	60.22	20.0
SD	-	0.04	0.05

MV = mean value

SD = standard deviation
*) of the last 10 measurements

**) Time from transfer of the test solution into the test vessel until end of each measurement

***) Values already corrected acc. to Harkins & Jordan

Validation

The surface tension of the reference item hexane was determined on 2012-07-16 as 18.33 ± 0.02 mN/m (20 °C) for the Ring Nr. 1, RI 21. This value is in the range of tolerance of ± 1 mN/m acc. to the literature value of 18.42 mN/m at 20 °C.

Conclusions:

The surface tension of a 1 g/L aqueous solution of calcium bis(2-ethylhexanoate) at 20 °C was determined to be 60.22 mN/m (standard deviation of 0.04 mN/m). Due to the fact that the surface tension is ≥ 60 mN/m, the test item is classified as not surface-active substance.

Reference 3

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2013-05-21 to 2013-06-20

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)

Remarks:

signed 2010-10-20

Type of method:

OECD harmonised ring method

Surface tension:

45.85 mN/m

Temp.:

20 °C

Conc.:

1 g/L

Remarks on result:

other: standard deviation of 0.04 mN/m; before filtration of the test solution

Surface tension:

46.36 mN/m

Temp.:

20 °C

Conc.:

1 g/L

Remarks on result:

other: standard deviation of 0.02 mN/m; after filtration of the test solution

Due to the fact, that undissolved particles were observed during the preparation overnight of the aqueous test solution, the resulting “solution” was treated additionally with ultrasound for 5 minutes at room temperature. But as there still remained a turbid test solution also in a repeated preparation (treated with ultrasound, stirred overnight and stored for further 5 days at room temperature), the procedure of the preparation was modified for the (final) testing as finally described under ‘Preparation of the test solution’.

Determination of the density

The density of the1 g/L aqueous solution of Fatty acids,C9-13-neo, calcium salts in double distilled water was determined in a preliminary measurement to be 1.006 g/cm³ (20.2 °C) before and 1.005 g/cm³ (20.0 °C) after filtration of the test solution.

Temperature

The temperature of the test solution during the whole measurements was 20.1 °C before filtration and 20.0 °C after filtration (for the last 10 measurements). The test room temperature during these measurements was 20.2 to 21.0 °C.

Time line of the study

After transfer of the test solution into the test vessel 42.8 minutes (before filtration) and 44.6 minutes (after filtration), respectively, were needed to reach an equilibrium at which 10 successive measurements with a standard deviation of ≤ 0.05 mN/m were possible.

Surface tension of a of a 1 g/L aqueous solution of Fatty acids,C9-13-neo, calcium salts

The determination was carried out in ten successive measurements with a standard deviation ≤ 0.05 mN/m.  

Surface tension, temperature before filtration of the test solution

Measurement No.*	Time** [min]	Surface Tension*** [mN/m]	Temperature [°C]
1	36.6	45.77	20.1
2	37.3	45.80	20.1
3	38.0	45.80	20.1
4	38.6	45.86	20.1
5	39.3	45.84	20.1
6	40.0	45.89	20.1
7	40.7	45.85	20.1
8	41.4	45.87	20.1
9	42.1	45.88	20.1
10	42.8	45.92	20.1
MV	-	45.85	20.1
SD [±]	-	0.04	0

MV = mean value

SD = standard deviation
*) of the last 10 measurements

**) Time from transfer of the test solution into the test vessel until end of each measurement

***) Values already corrected acc. to Harkins & Jordan

Surface tension, temperature after filtration of the test solution

Measurement No.*	Time** [min]	Surface Tension*** [mN/m]	Temperature [°C]
1	38.4	46.39	20.0
2	39.1	46.36	20.0
3	39.8	46.40	20.0
4	40.5	46.32	20.0
5	41.2	46.35	20.0
6	41.9	46.37	20.0
7	42.6	46.38	20.0
8	43.3	46.36	20.0
9	44.0	46.34	20.0
10	44.6	46.33	20.0
Mean	-	46.36	20.0
SD [±]	-	0.02	0

MV = mean value

SD = standard deviation
*) of the last 10 measurements

**) Time from transfer of the test solution into the test vessel until end of each measurement

***) Values already corrected acc. to Harkins & Jordan

Validation

The surface tension of the reference item hexane was determined on 2012-07-16 as 18.33 ± 0.02 mN/m (20 °C) for the Ring Nr. 1, RI 21. This value is in the range of tolerance of ± 1 mN/m acc. to the literature value of 18.42 mN/m at 20 °C.

Conclusions:

The surface tension of a 1 g/L aqueous solution of Fatty acids, C9-13-neo, calcium salts at 20 °C was determined to be 45.85 mN/m (standard deviation of 0.04 mN/m) before filtration and 46.36 mN/m (standard deviation of 0.02 mN/m) after filtration of the test solution. Due to the fact that the surface tensions are < 60 mN/m, the test item is classified as surface-active substance.

Reference 4

Endpoint:

surface tension

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Description of key information

2-ethylhexanoic acid, copper salt represents an inorganic salt containing an anion of an acid with a carbon chain length of 6, it can safely be assumed that this substance is not surface active.

Additional information

Three tests on the surface tension according to OECD TG 115 were recently conducted for a representative sub-set of RMC substances, i.e. calcium bis(2-ethylhexanoate) (carbon chainlength: 6), fatty acids, C6-19-branched, zinc salts (carbon chain length: 6-19) and fatty acids, C9-13, neo, calcium salts (carbon chain length: 9-13), yielding a result as surface-active substance for fatty acids, C6-19-branched, zinc salts (52.5 mN/m) and fatty acids, C9-13, neo, calcium salts (45.8 mN/m) and not surface-active substance for calcium bis(2-ethylhexanoate) (60.22 mN/m). Since 2-ethylhexanoic acid, copper salt represents an inorganic salt containing an anion of an acid with a carbon chain length of 6, it can safely be assumed that this substance is not surface active. As stated in the ECHA Guidance on information requirements and chemical safety assessment, Chapter R.7a: Endpoint specific guidance, R.7.1.18.1, May 2008, p.182, 185, a low surface tension (of below 33 mN/m) is one indicator for aspiration hazard. It can safely be assumed that the surface tension effect of 2-ethylhexanoic acid, copper salt is above 33 mN/m, thus further testing is not required (in accordance with Regulation (EC) 1907/2006, Annex VII, section 7.6, Column 2).