Reaction mass of 3-[3-(9-butyl-1,1,3,3,5,5,7,7,9,9-decamethylpentasiloxanyl)propoxy]-2-hydroxypropyl 2methylprop-2-enoate and 1-[3-(9-butyl-1,1,3,3,5,5,7,7,9,9-decamethylpentasiloxanyl)propoxy]-3-hydroxypropan-2-yl 2-methylprop-2-enoate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

key study

Study period:

17 May 2008 to 15 July 2008

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study conducted to GLP and in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not effect the quality of the results.

Qualifier:

equivalent or similar to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

yes

Remarks:

Due to the nature of the substance both a visual estimation of water solubility was obtained and also a calculation performed using computer-based specialist estimation software.

Principles of method if other than guideline:

See discussion section.

GLP compliance:

yes (incl. QA statement)

Type of method:

other: visual estimate and computer estimation.

Water solubility:

< 1.1 mg/L

Temp.:

20 °C

pH:

6.8

Details on results:

Visual Estimation:
The water solubility has been determined to be less than 1.1 mg/l, as excess undissolved test material was present in the sample. The pH of the solution was 6.8.

Atom/Fragment Contribution:
Information supplied indicated that the test material was mono(hydroxymethacryloxypropoxypropyl) polydimethylsiloxane, with a molecular weight of ~500-1000 g/mole. Calculations, based on the lower and higher ends of this range, gave a water solubility estimate of 0.003695 to 6.6 x 10-13 mg/l at 25°C.

Discussion:

It is possible that the test material had not reached saturation equilibrium in the visual estimation and that impurities may have influenced the results.

Attempts were made to develop a validated low concentration analytical method using solvent-solvent extraction, solid-phase extraction and freeze-drying methodologies; the best recoveries were determined for the freeze-drying methodology, which gave a mean recovery of 67.5% (range: 61.2 to 72.2 %). These results were not particularly ideal, but a decision was made to perform a flask-shake test. However, on performing a flask-shake test, it was noted that all of the sample solutions contained excess undissolved test material as a fine dispersion throughout the samples, which could not be removed by ultra-centrifugation. As the guideline states that the samples should be free from undissolved material, the samples were filtered using sub-micron membrane filters, which resulted in solutions visibly free from undissolved test material. Recoveries were then repeated using sub-micron filtration of the samples before the freeze-drying step, which resulted in no test material being recovered (none detected). This would indicate that the majority of the test material was removed by the filter(s), which would propose that the majority of the test material was not actually dissolved in the initial recovery solutions, but would have been finely dispersed. Therefore, as no acceptable recovery methodology could be found, it was decided to determine the water solubility by visual appraisal and estimation using computer-based estimation software.

Conclusions:

Using a visual estimation technique, the test material has been determined to have a water solubility of less than 1.1 x 10-3 g/l at 20.0 ± 0.5°C. Using an atom/fragment contribution method, the water solubility of the test material has been estimated to be 3.695 x10-6 to 6.6 x 10-16 g/l at 25°C.

Executive summary:

Method

The determination was carried out using a procedure based on the flask method, Method A6 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

The calculation was performed using computer-based specialist estimation software, WSKOWWIN, version 1.41, © 2000 US Environmental Protection Agency.

Conclusion

Using a visual estimation technique, the test material has been determined to have a water solubility of less than 1.1 x10^-3g/l at 20.0 ± 0.5°C. Using an atom/fragment contribution method, the water solubility of the test material has been estimated to be 3.695 x10^-6to 6.6 x 10^-16g/l at 25°C.

Description of key information

Using a visual estimation technique, the test material has been determined to have a water solubility of less than 1.1 x10-3g/l at 20.0 ± 0.5°C.

Key value for chemical safety assessment

Water solubility:

1.1 mg/L

at the temperature of:

20 °C

Additional information

Method

The determination was carried out using a procedure based on the flask method, Method A6 of Commission Directive 92/69/EEC (which constitutes Annex V of Council Directive 67/548/EEC).

The calculation was performed using computer-based specialist estimation software, WSKOWWIN, version 1.41, © 2000 US Environmental Protection Agency.

Conclusion

Using a visual estimation technique, the test material has been determined to have a water solubility of less than 1.1 x10^-3g/l at 20.0 ± 0.5°C. Using an atom/fragment contribution method, the water solubility of the test material has been estimated to be 3.695 x10^-6 to 6.6 x 10^-16 g/l at 25°C.