Registration Dossier

Diss Factsheets

Physical & Chemical properties

Partition coefficient

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The result was obtained by the valid application of an appropriate predictive method.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Principles of method if other than guideline:
The result was obtained using an appropriate QSAR method. The model is an adaptation of the existing SRC model KOWWIN v1.68, which is a component of the EPIWIN Suite. The model is based on fragment values. That is, the chemical structure is broken down into its constituent functional groups, and the contribution of each group toward the overall partition coefficient is calculated. The constants used within KOWWIN have been derived by SRC from a wide range of organic chemicals. Whilst this method is good in principle, the model was developed using a wide range of organic chemicals and only a few organosilicon compounds. Therefore, a validation procedure was undertaken to assess the applicability of the model to alkoxysilane compounds. It was noted that the model under-predicted log Kow for alkoxysilanes; therefore, a correction factor is applied when this structural feature is present. The adapted model applies to di- and tri-alkoxysilanes.
Partition coefficient type:
octanol-water
Type:
log Pow
Partition coefficient:
-2.2
Temp.:
20 °C
Conclusions:
An octanol-water partition coefficient value of -2.2 was obtained using an accepted calculation method. The result is considered to be reliable.
Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The result was obtained by the valid application of an appropriate predictive method.
Justification for type of information:
QSAR prediction: migrated from IUCLID 5.6
Principles of method if other than guideline:
The result was obtained using an appropriate QSAR method. The model is an adaptation of the existing SRC model KOWWIN v1.68, which is a component of the EPIWIN Suite. The model is based on fragment values. That is, the chemical structure is broken down into its constituent functional groups, and the contribution of each group toward the overall partition coefficient is calculated. The constants used within KOWWIN have been derived by SRC from a wide range of organic chemicals. Whilst this method is good in principle, the model was developed using a wide range of organic chemicals and only a few organosilicon compounds. Therefore, a validation procedure was undertaken to assess the applicability of the model to alkoxysilane compounds. It was noted that the model under-predicted log Kow for alkoxysilanes; therefore, a correction factor is applied when this structural feature is present. The adapted model applies to di- and tri-alkoxysilanes.
Type:
log Pow
Partition coefficient:
2
Temp.:
20 °C
pH:
7
Conclusions:
An octanol-water partition coefficient value of 2.0 was obtained using an accepted calculation method. The result is considered to be reliable.

Description of key information

log Kow [[3-(2,3-epoxypropoxy)propyl]triethoxysilane]: 2.0 (QSAR)

log Kow [2,3-dihydroxypropoxypropylsilanetriol]: -3.8 (QSAR)

log Kow [ethanol]: -0.3

Key value for chemical safety assessment

Log Kow (Log Pow):
2
at the temperature of:
20 °C

Additional information

A predicted log Kow value of 2.0 was determined for the registered substance using a validated QSAR estimation method. The result is considered to be reliable.

In contact with water, [3-(2,3-epoxypropoxy)propyl]triethoxysilane will hydrolyse moderately rapidly to form 2,3-dihydroxypropoxypropylsilanetriol and ethanol.

The log Kow of the silanol hydrolysis product, 2,3-dihydroxypropoxypropylsilanetriol was estimated to be -3.8 at 20°C using a validated QSAR estimation method.

Ethanol has a reported log Kow of -0.3 (Hansch C 1995).

Reference:

Hansch C (1995). Hansch. C., A. Leo and D. Hoekman.1995. Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Professional Reference Book, American Chemical Society