Estr-5(10)-en-17-one, 3,3-dimethoxy-

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.5 (Surface Tension)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: user manual K122 (Krüss GmbH)

Deviations:

no

GLP compliance:

yes

Type of method:

plate method

Key result

Surface tension:

> 60 mN/m

Temp.:

20 °C

Conc.:

90 other: % saturation

Calibration of the tensiometer:

Surface tension of water at 20 °C, cited in the literature: ¿₀ = 72.75 mN/m (Handbook of Chemistry and Physics, 54^th edition (1973 -1974), Chem. Rubber Co.)

measured value of surface tension at 20 °C

73.23 mN/m

72.86 mN/m

Aqueous suspensions containing an excess of the substance were prepared and equilibrated for different but defined times. After centrifugation of the suspensions samples were taken diluted to 90% according to the guideline and analysed by HPLC to obtain the actual concentration of unhydrolysed substance in the solution.

The results show that the concentration of the substance approximates saturation only at short saturation times. As saturation occurs in presence of solid substance the loss of substance caused by hydrolysis was delivered from the solid phase. On the other side the concentration of the hydrolysis product increases. In an additional experiment a suspension of the substance was stirred for 1 h. After centrifugation (30 min, 30000g) the clear saturated solution was decanted and continued to stir. Measurements of concentration and of surface tension of the test solution were performed at certain time intervals.

Further the results show that in a solution without solid phase the substance was progressively consumed by hydrolysis and the hydrolysis product increases consequently.

As hydrolysis proceeds the surface tension of the solution increases indicating that the hydrolysis product is less surface active as the substance in question. Therefore the surface tension of the test solution was not decreased by the hydrolysis of the substance.

Since all saturated solutions obtained at different saturation times have surface tensions sigma > 60 mN/m the substance can be considered to be not surface active in aqueous solution in accordance with the EC Guideline A5.

Conclusions:

The surface tensions of solutions saturated at different times were determined to be > 60 mN/m at 20°C. The substance can be considered to be not surface active in aqueous solution.

Executive summary:

Because of hydrolysis only solutions containing different amounts of the substance and of its hydrolysis products were available. Saturated solutions were prepared by saturation for different saturation times, diluted to 90% and analysed by HPLC. Their surface tensions were measured with a tensiometer according to the EC Guideline and the user manual K122 .

It was found that the hydrolysis product is less surface active as the substance and the surface tension of the test solution was not decreased by the progressive hydrolysis.

The surface tensions of solutions saturated at different times were determined to be > 60 mN/m at 20°C.

Therefore the substance can be considered to be not surface active in aqueous solution in accordance with the EC Guideline A5.

Description of key information

The surface tensions of solutions saturated at different times were determined to be > 60 mN/m at 20°C. The substance can be considered to be not surface active in aqueous solution.

Key value for chemical safety assessment

Surface tension:

60