Tris(trimethylsilyl) phosphate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

(Q)SAR

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
QSAR Toolbox 2.3.0.1132
2. MODEL (incl. version number)
WSKOWWIN (EPISUITE) v1.42
3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
O=P(O[Si](C)(C)C)(O[Si](C)(C)C)O[Si](C)(C)C
4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
[[Explain how the model fulfils the OECD principles for (Q)SAR model validation. Consider attaching the QMRF and/or QPRF or providing a link]
- Defined endpoint:
Physical Chemical Properties#Water Solubility
- Unambiguous algorithm:
WSKOWWIN estimates water solubility for any compound with one of two possible equations. The equations are equations 19 and 20 from Meylan and Howard (1994a) or equations 11 and 12 from the journal article (Meylan et al., 1996). The equations are:
log S (mol/L) = 0.796 - 0.854 log Kow - 0.00728 MW + ΣCorrections
log S (mol/L) = 0.693 - 0.96 log Kow - 0.0092(Tm-25) - 0.00314 MW + ΣCorrections
(where MW is molecular weight, Tm is melting point (MP) in deg C [used only for solids]) ... Summation of Corrections (ΣCorrections) are applied as described in Appendix E. When a measured MP is available, that equation is used; otherwise, the equation with just MW is used.
For Tris(trimethylsilyl) phosphate, no applicable correction factors are available.

- Defined domain of applicability:
There are 1450 compounds in the training set. The minimum and maximum values for Training set are the following:
Range of water solubilities in the Training set:
Minimum = 4 x 10-7 mg/L (octachlorodibenzo-p-dioxin); Maximum = completely soluble (various)
Range of Molecular Weights in the Training set:
Minimum = 27.03 (hydrocyanic acid); Maximum = 627.62 (hexabromobiphenyl)
Range of Log Kow values in the Training set:
Minimum = -3.89 (aspartic acid); Maximum = 8.27 (decachlorobiphenyl)
- Descriptor domain:
The WSKOWWIN program estimates the water solubility of an organic compound using the compounds log octanol-water partition coefficient (log Kow). Standard linear regressions were used to fit water solubility (as log S) with log Kow, melting point and molecular weight.

- Structural domain:
The WSKOWWIN program estimates the water solubility of an organic compound using the compounds log octanol-water partition coefficient (log Kow). A database of more than 8400 compounds with reliably measured log Kow values had already been compiled from available sources. Most experimental values were taken from a "star-list" compilation of Hansch and Leo (1985) that had already been critically evaluated or an extensive compilation by Sangster (1993) that includes many "recommended" values based upon critical evaluation. Other log Kow values were taken from sources located through the Environmental Fate Data Base (EFDB) system. A few values were taken from Section 4a, 8d, and 8e submissions to U.S. EPA under the Toxic Substances Control Act. Water solubilities were collected from the AQUASOL dATAbASETM of the University of Arizona, Syracuse Research Corporation's PHYSPROP© Database, and sources located through the Environmental Fate Data Base (EFDB) system. Water solubilities were primarily constrained to the 20-25 °C temperature range with 25 °C being preferred. Melting points were collected from sources such as AQUASOL dATAbASETM, PHYSPROP©, and EDFB as well as the Handbook of Chemistry and Physics and the Aldrich Catalog.
A dataset of 1450 compounds (941 solids, 509 liquids) having reliably measured water solubility, log Kow and melting point was used as the training set for developing the new estimation algorithms for water solubility. Standard linear regressions were used to fit water solubility (as log S) with log Kow, melting point and molecular weight. Residual errors from the initial regression fit were examined for compounds sharing common structural features with relatively consistent errors. On that basis, 12 compound classes were initially identified and added to the regression to comprise a multi-linear regression including log Kow, melting point and/or molecular weight plus 12 correction factors. Each correction factor is counted a maximum of once per structure [if applicable], no matter how many times the applicable fragment occurs.

- Mechanistic domain:
A posteriori mechanistic interpretation, consistent with published scientific interpretations of experiments.

- Similarity with analogues in the training set:



6. ADEQUACY OF THE RESULT
[Explain how the prediction fits the purpose of classification and labelling and/or risk assessment]
The molecular weight of the substance is 314.54, within the scope of the model (27.03.02~627.62).
The log Kow of the substance is 4.72, within the scope of the model (-3.89~8.27).
Therefore, the predicted value is considered to be reliable.

Guideline:

other: REACH guideline on QSARs R.6

Key result

Water solubility:

0.935 mg/L

Remarks on result:

not measured/tested

Details on results:

WSKOWWIN estimates water solubility for any compound with one of two possible equations. The equations are equations 19 and 20 from Meylan and Howard (1994a) or equations 11 and 12 from the journal article (Meylan et al., 1996). The equations are:
log S (mol/L) = 0.796 - 0.854 log Kow - 0.00728 MW + ΣCorrections
log S (mol/L) = 0.693 - 0.96 log Kow - 0.0092(Tm-25) - 0.00314 MW + ΣCorrections
(where MW is molecular weight, Tm is melting point (MP) in deg C [used only for solids]) ... Summation of Corrections (ΣCorrections) are applied as described in Appendix E. When a measured MP is available, that equation is used; otherwise, the equation with just MW is used.
For Tris(trimethylsilyl) phosphate, no applicable correction factors are available.

There are 1450 compounds in the training set. The minimum and maximum values for Training set are the following:

Range of water solubilities in the Training set:

Minimum  =  4 x 10^-7mg/L (octachlorodibenzo-p-dioxin); Maximum =  completely soluble (various)

Range of Molecular Weights in the Training set:

Minimum  =  27.03 (hydrocyanic acid); Maximum =  627.62 (hexabromobiphenyl)

Range of Log Kow values in the Training set:

Minimum  =  -3.89 (aspartic acid); Maximum =  8.27 (decachlorobiphenyl)

When an experimental melting point is available, WSKOWWIN applies the equation containing both a melting point and the molecular weight (MW) parameters. In the absence of a melting point, the equation containing just the molecular weight is used to make the estimate. All compounds in the 1450 compound training set have known melting points or are known to be liquids at 25°C. The accuracy statistics for the two equations are as follows:

	Melt Pt + MW	MW only
r^2	0.970	0.934
std deviation	0.409	0.585
avg deviation	0.313	0.442

Conclusions:

The water solubility of substance is predicted to be 0.9355 mg/L.

Description of key information

The water solubility of substance is predicted to be 0.9355 mg/L.

Key value for chemical safety assessment

Water solubility:

0.935 mg/L

at the temperature of:

20 °C