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Physical & Chemical properties

Surface tension

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Reference
Endpoint:
surface tension
Type of information:
other: experimental result obtained on one of the main constituents
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 115 (Surface Tension of Aqueous Solutions)
Qualifier:
according to
Guideline:
EU Method A.5 (Surface Tension)
GLP compliance:
yes (incl. certificate)
Type of method:
OECD harmonised ring method
Key result
Surface tension:
48.45 mN/m
Temp.:
20 °C
Conc.:
90 vol%

Determination of the density

The buoyancy method yielded a density of the test solution of 1.004 g/cm3 at 20.0°C. The density was used for the correction method of Harkins and Jordan in the determination of the surface tension.

Temperature

The temperature of the test solution during the whole series of measurements was between 19.9 and 20.0°C.

Time line of the surface tension determination

Start of measurement was 27.1 minutes after transfer of the test solution into the vessel. After that time, 15.2 minutes were needed to reach equilibrium at which 10 successive measurements were successfully achieved with a standard deviation of <= 0.05 mN/m.

Surface tension of the test chemical

Measurement No. 1) Time 2) (min) Time 3) (min) Surface Tension (mN/m) Temperature (°C)
1 36.13 9.01 48.39 20.0
2 36.83 9.71 48.41 20.0
3 37.54 10.42 48.41 20.0
4 38.25 11.13 48.44 20.0
5 38.96 11.84 48.44 20.0
6 39.65 12.53 48.44 20.0
7 40.33 13.21 48.49 20.0
8 40.98 13.86 48.50 20.0
9 41.75 14.64 48.51 20.0
10 42.41 15.29 48.52 20.0
Mean  -  -  48.45 20.0
SD (+/-)  -  - 0.05 0.0

SD = standard deviation

1) of the last 10 measurements

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

3) Time start of measurement until end of each measurement

Conclusions:
The surface tension of a 90% saturated aqueous solution of the test chemical 4-(1-phenylethyl)phenol was determined to be 48.45 mN/m (SD +/- 0.05 mN/m) at 20°C.
Executive summary:

The test was performed to determine the surface tension of an aqueous solution with a concentration of 90% of the saturation concentration of the test chemical 4-(1-phenylethyl)phenol via tensiometer using the OECD-harmonised ring method. The study was performed according to OECD TG 115, EU Method A.5 and in compliance to GLP. The density of the test solution was determined in a preliminary measurement via the buoyancy method to be 1.004 g/cm3 (20.0°C). The temperature of the test solution during the whole series of measurements was between 19.9 and 20.0°C, and the validity criteria for the test were fulfilled. The determination was carried out with a tensiometer in ten successive measurements (SD ≤ 0.05 mN/m). The surface tension of a 90% saturated aqueous solution of the test item was determined to be 48.45 mN/m (SD +/- 0.05 mN/m) at 20°C. Considering that distilled water has a surface tension of 72.75 mN/m at 20°C and the test chemical showed a surface tension below 60 mN/m under the conditions of this test method, the test chemical should be regarded as being surface-active material.

Description of key information

The surface tension of 4-­monostyryl phenol (4-MSP) was determined by means of a tensiometer using the OECD-­harmonized ring method in accordance with OECD Guidance 115 and EU method A.5. The surface tension of a 90% saturated aqueous solution of the test chemical was determined to be 48.45 mN/m (SD +/-­ 0.05 mN/m) at 20°C. As the surface tension value is below the threshold of 60 mN/m under the conditions of this test method, the test chemical should be regarded as having some surface-­active potential.

Key value for chemical safety assessment

Surface tension:
48.45

Additional information

The surface tension was tested only on the 4-­MSP isomer. This isomer represents the “worst-case” scenario with regard to the surface activity, as in this chemical structure, the steric split between the hydrophopic part (the styryl group) and the hydrophilic moiety (the hydroxyl group) is at maximum. The measured surface tension value for 4 -MSP is 48.45 mN/m, which indicates that the substance has some surface active potential. It is however to be noted that the chemical structure of 4­MSP is not characteristic of a ‘true surfactant’. This is reflected in the obtained value for surface tension, which is still rather high when compared to that of ‘true surfactants’, which typically yield surface tension values around 26-­28 mN/m. As the steric split in 2-MSP is less explicit, it is reasonable to assume that 2­MSP has even less potential for surface active behavior, and thus would yield a higher surface tension value.