Tin bis(2-ethylhexanoate)

Surface tension

Link to relevant study record(s)

Reference

Endpoint:

surface tension

Type of information:

experimental study

Adequacy of study:

key study

Study period:

15 MAR 2010 - 19 MAY 2010

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

GLP compliance:

no

Remarks:

This study was conducted in a facility operating to GPL within the UK national GPL monitoring programme, but the study report was not audited by the QA unit. No formal claim for GPL compliance is made for this study.

Type of method:

ring method

Surface tension:

55.9 mN/m

Temp.:

20.5 °C

Conc.:

1 g/L

Remarks on result:

other: The original test substance mixture was prepared at 1.1 g/L (0.11% wt.) in water, then diluted by 90% to give an approximate 0.1% wt. solution, as required by the guideline.

pH of the test substance solution was 6.2 after measurement of surface tension. The method/instrument was calibrated by measuring surface tension of double-distilled water at ~20.5 °C, giving a mean value of 72.1 nM/m. The deviation of this value from the literature value of 72.6 was used to adjust calibration of the instrument for measurements of the test substance solution.

Conclusions:

The surface tension was determined to be 55.9 mN/m at 20.5 +/- 0.5 deg C at a nominal concentration of 1.1 g/L. The test material and/or its dissociation/hydrolysis products are considered to be surface active.

Executive summary:

The surface tension of Tin bis(2-ethylhexanoate) and its dissociation/hydrolysis products in water were determined using the OECD Guideline 115 (ring method). Tin bis(2-ethylhexanoate) is a salt which dissociates upon introduction to water. At pH > 6, the Sn(II) cation is reported to form insoluble Sn(OH)₂. The pKa for the 2-ethyl hexanoic acid anion is 4.8, and therefore exists primarily as the anionic species at pH > 6. The results of this study are expected to reflect the surface-active properties of the water-soluble dissociation products of Tin bis(2-ethylhexanoate) (i.e.,2 -ethylhexanoic acid). This substance, having a hydrophylic carboxylate group and hydrophobic C6 hydrocarbon tail, is expected to exhibit surface-active properties, as evidenced in the results of this study. The reported surface tension of an approximately 0.1% wt. solution of the dissociation products of Tin bis(2-ethylhexanoate) is 55.9 mN/m at 20.5 °C.

Description of key information

The surface tension of Tin bis(2-ethylhexanoate) and its dissociation/hydrolysis products in water were determined using the OECD Guideline 115 (ring method). Tin bis(2-ethylhexanoate) is a salt which dissociates upon introduction to water. At pH > 6, the Sn(II) cation is reported to form insoluble Sn(OH)₂. The pKa for the 2-ethyl hexanoic acid anion is 4.8, and therefore exists primarily as the anionic species at pH > 6. The results of this study are expected to reflect the surface-active properties of the water-soluble dissociation products of Tin bis(2-ethylhexanoate) (i.e.,2 -ethylhexanoic acid). This substance, having a hydrophylic carboxylate group and hydrophobic C6 hydrocarbon tail, is expected to exhibit surface-active properties, as evidenced in the results of this study. The reported surface tension of an approximately 0.1% wt. solution of the dissociation products of Tin bis(2-ethylhexanoate) is 55.9 mN/m at 20.5 °C.

Key value for chemical safety assessment

Surface tension:

55.9

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

1