[No public or meaningful name is available]

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published handbook data

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 107 (Partition Coefficient (n-octanol / water), Shake Flask Method)

GLP compliance:

not specified

Type of method:

shake-flask method to: flask method

Partition coefficient type:

octanol-water

Analytical method:

gas chromatography

Type:

log Pow

Partition coefficient:

4.5

Temp.:

22 °C

pH:

ca. 7

Remarks on result:

other:

Remarks:

Temperature not specified (room temp.); pH not specified.

Details on results:

The octanol/water coefficient was measured to be 32,000. The logPow was calculated to be 4.5. Temperature was not specified, and thus room temperature was set to a typicla value of 22°C. pH was not specified. Typically pure water has a pH of about 7.

The octanol/water coefficient was measured to be 32000. The logPow was calculated to be 4.5.

Conclusions:

The octanol/water coefficient was measured to be 32,000. The logPow was calculated to be 4.5.

Executive summary:

The octanol/water coefficient of diphenyl tolyl phosphate was measured to be 32,000. The logPow was calculated to be 4.5.

Reference 2

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

supporting 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
Individual model KOWWIN included in the Estimation Programs Interface (EPI) Suite.

2. MODEL (incl. version number)
KOWWIN v1.68 included in EPISuite v 4.11, ©2000 - 2012

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
A SMILES NOTATION was entered in the initial data entry screen. In the structure window, the molecular weight, structural formula and the structure of the input SMILES notation is shown.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL

a. Defined Endpoint: Octanol-water partition coefficient

b. Explicit algorithm:
The program methodology is known as an Atom/Fragment Contribution (AFC) method. KOWWIN uses a "fragment constant" methodology to predict log P. In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log P estimate.
The equation is as follows: Log Kow = Sum (fini) + Sum (cjnj) + 0.229, where Sum (fini) is the summation of fi (the coefficient for each atom/fragment) times ni (the number of times the atom/fragment occurs in the structure), and (cjnj) is the summation of cj (the coefficient for each correction factor) times nj (the number of times the correction factor occurs (or is applied) in the molecule). The program requires only a chemical structure to estimate a log P. KOWWIN initially separates a molecule into distinct atom/fragments. For various types of structures, that log P estimates made from atom/fragment values alone could or needed to be improved by inclusion of substructures larger or more complex than "atoms"; hence, correction factors were added to the AFC method.

c. Descriptor selection:
As the program requires only a chemical structure to estimate a log P, KOWWIN initially separates a molecule into distinct atom/fragments. Each non-hydrogen atom (e.g. carbon, nitrogen, oxygen, sulfur, etc.) in a structure is a "core" for a fragment; the exact fragment is determined by what is connected to the atom. Several functional groups are treated as core "atoms". Connections to each core "atom" are either general or specific. For example, aromatic carbon, aromatic oxygen and aromatic sulfur atoms have nothing but general connections; i.e., the fragment is the same no matter what is connected to the atom. In contrast, the aliphatic carbon atom does not matter what is connected to -CH3, -CH2-, or -CH<, the fragment is the same; however, an aliphatic carbon with no hydrogens has two possible fragments: (a) if there are four single bonds with 3 or more carbon connections and (b) any other not meeting the first criteria. Additionally, for various types of structures, need to be improved by inclusion of substructures larger or more complex than "atoms" by adding correction factors. The correction factors have two main groupings: first, factors involving aromatic ring substituent positions and second, miscellaneous factors. In general, the correction factors are values for various steric interactions, hydrogen-bondings, and effects from polar functional substructures. Individual correction factors were selected through a tedious process of correlating the differences (between log P estimates from atom/fragments alone and measured log P values) with common substructures.

d. Defined domain of applicability: For each fragment the maximum number of instances of that fragment in any of the 2447 training set compounds and 10946 validation set compounds is located in Appendix D of the help menu of the EPISuite data entry page. The minimum and the maximum values for molecular weight are the following:
Training Set Molecluar Weights: 18.02-719.92 g/mol
Validation Set Molecular Weights: 27.03-991.15 g/mol

e. Statistical characteristics: Correlation coefficient of the total training set r² = 0.982; Correlation coefficient of the total validation set r² = 0.943.
KOWWIN has been tested on an external validation dataset of 10,946 compounds. The validation set includes a diverse selection of chemical structures that rigorously test the predictive accuracy of any model. It contains many chemicals that are similar in structure to chemicals in the training set, but also many chemicals that are different from and structurally more complex than chemicals in the training set. The average molecular weight of compounds in the validation set is 258.98 versus 199.98 for the training set.
(Training dataset includes a total of 2447 compounds)
(Validation dataset includes a total of 10946 compounds)

f. Mechanistic interpretation: The structural fragments used as descriptors reflect the lipophilic or hydrophobic properties of the substances, and so the octanol-water partition coefficient.

5. APPLICABILITY DOMAIN
a. Descriptor domains:
i. Molecular weights: With a molecular weight of 340.3 g/mol the substance is within the range of the training set (18.02 - 719.92 g/mol) as well as in the range of the validation set (27.03 - 991.15 g/mol).
ii. Structural fragment domain: Regarding the structure of cresyl diphenylphosphate, the fragment descriptors found by the program are complete and listed in Appendix D (KOWWIN Fragment and Correction Factor descriptors). Additionally the substance is not listed in Appendix F (Compounds that exceed the Fragment & Molecular Weight Domains).
iii. Mechanism domain: NO INFORMATION AVAILABLE
iv. Metabolic domain, if relevant: NOT RELEVANT
b. Structural analogues: Optional
i. Considerations on structural analogues: Optional

6. ADEQUACY OF THE RESULT
a. Regulatory purpose: The data may be used under any regulatory purpose.
b. Approach for regulatory interpretation of the model result: If no experimental data are available, the estimated value is used to fill data gaps needed for hazard and risk assessment, classification and labelling and PBT / vPvB assessment. Further the value can be used for other calculations.
c. Outcome: The prediction of the logarithmic octanol-water partition coefficient yields a useful result for further evaluation.
d. Conclusion: The result is considered as useful for regulatory purposes.

Guideline:

other: REACH guidance QSARs R6, May/July 2008

Deviations:

no

Principles of method if other than guideline:

Estimation Program Interface EPI-Suite version 4.11: KOWWIN for estimating the logarithmic octanol-water partition coefficient (log Kow).
The Estimation Programs Interface was developed by the US Environmental Agency's Office of Pollution Prevention and Toxics and Syracuse Research Corporation (SRC).© 2000 - 2012 U.S. Environmental Protection Agency for EPI SuiteTM (Published online in November 2012).

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

5.25

Remarks on result:

other: Temp. and pH are not reported

Details on results:

SMILES notations of three regioisomeric cresyl diphenyl phosphates were entered in the initial data entry screen, always resulting in the same log Kow.

Validity of model:

1. Defined Endpoint: Octanol-water partition coefficient

2. Unambiguous algorithm: The molecule is separated into distinct atom/fragments using an Atom/Fragment Contribution method. Based on structure of the molecule, the following fragments were applied: -CH3 (aliphatic carbon), -C- (aromatic carbon), -O-P (aromatic attach) and O=P. The number of times of the fragments that occur in the structure of the substance applied by the program is verified.

3. Applicability domain: With a molecular weight of 340.3 g/mol the substance is within the range of the training set (18.02 - 719.92) as well as in the range of the validation set (27.03 - 991.15).

4. Statistical characteristics: Correlation coefficient of the total training set r² = 0.982; Correlation coefficient of the total validation set r² = 0.943.

5. Mechanistic interpretation: The structural fragments used as descriptors reflect the lipophilic or hydrophobic properties of the substances, and so the octanol-water partition coefficient.

6. Adequacy of prediction: The result for cresyl diphenyl phosphates falls within the applicability domain described above and the estimation rules applied for the substance appears appropriate. Therefore the predicted value can be considered reliable yielding a useful result for further assessment.

Conclusions:

The QSAR determination of the logarithmic octanol-water partition coefficient for cresyl diphenyl phosphate using the model KOWWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 5.25. The predicted value can be considered reliable yielding a useful result for further assessment.

Executive summary:

The logarithmic octanol-water partition coefficient (log Kow) for cresyl diphenyl phosphate was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v 4.11. The log Kow was estimated to be 5.25. The predicted value can be considered reliable yielding a useful result for further assessment.

Reference 3

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

supporting 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
Individual model KOWWIN included in the Estimation Programs Interface (EPI) Suite.

2. MODEL (incl. version number)
KOWWIN v1.68 included in EPISuite v 4.11, ©2000 - 2012

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
A SMILES NOTATION was entered in the initial data entry screen. In the structure window, the molecular weight, structural formula and the structure of the input SMILES notation is shown.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL

a. Defined Endpoint: Octanol-water partition coefficient

b. Explicit algorithm:
The program methodology is known as an Atom/Fragment Contribution (AFC) method. KOWWIN uses a "fragment constant" methodology to predict log P. In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log P estimate.
The equation is as follows: Log Kow = Sum (fini) + Sum (cjnj) + 0.229, where Sum (fini) is the summation of fi (the coefficient for each atom/fragment) times ni (the number of times the atom/fragment occurs in the structure), and (cjnj) is the summation of cj (the coefficient for each correction factor) times nj (the number of times the correction factor occurs (or is applied) in the molecule). The program requires only a chemical structure to estimate a log P. KOWWIN initially separates a molecule into distinct atom/fragments. For various types of structures, that log P estimates made from atom/fragment values alone could or needed to be improved by inclusion of substructures larger or more complex than "atoms"; hence, correction factors were added to the AFC method.

c. Descriptor selection:
As the program requires only a chemical structure to estimate a log P, KOWWIN initially separates a molecule into distinct atom/fragments. Each non-hydrogen atom (e.g. carbon, nitrogen, oxygen, sulfur, etc.) in a structure is a "core" for a fragment; the exact fragment is determined by what is connected to the atom. Several functional groups are treated as core "atoms". Connections to each core "atom" are either general or specific. For example, aromatic carbon, aromatic oxygen and aromatic sulfur atoms have nothing but general connections; i.e., the fragment is the same no matter what is connected to the atom. In contrast, the aliphatic carbon atom does not matter what is connected to -CH3, -CH2-, or -CH<, the fragment is the same; however, an aliphatic carbon with no hydrogens has two possible fragments: (a) if there are four single bonds with 3 or more carbon connections and (b) any other not meeting the first criteria. Additionally, for various types of structures, need to be improved by inclusion of substructures larger or more complex than "atoms" by adding correction factors. The correction factors have two main groupings: first, factors involving aromatic ring substituent positions and second, miscellaneous factors. In general, the correction factors are values for various steric interactions, hydrogen-bondings, and effects from polar functional substructures. Individual correction factors were selected through a tedious process of correlating the differences (between log P estimates from atom/fragments alone and measured log P values) with common substructures.

d. Defined domain of applicability: For each fragment the maximum number of instances of that fragment in any of the 2447 training set compounds and 10946 validation set compounds is located in Appendix D of the help menu of the EPISuite data entry page. The minimum and the maximum values for molecular weight are the following:
Training Set Molecluar Weights: 18.02-719.92 g/mol
Validation Set Molecular Weights: 27.03-991.15 g/mol

e. Statistical characteristics: Correlation coefficient of the total training set r² = 0.982; Correlation coefficient of the total validation set r² = 0.943.
KOWWIN has been tested on an external validation dataset of 10,946 compounds. The validation set includes a diverse selection of chemical structures that rigorously test the predictive accuracy of any model. It contains many chemicals that are similar in structure to chemicals in the training set, but also many chemicals that are different from and structurally more complex than chemicals in the training set. The average molecular weight of compounds in the validation set is 258.98 versus 199.98 for the training set.
(Training dataset includes a total of 2447 compounds)
(Validation dataset includes a total of 10946 compounds)

f. Mechanistic interpretation: The structural fragments used as descriptors reflect the lipophilic or hydrophobic properties of the substances, and so the octanol-water partition coefficient.

5. APPLICABILITY DOMAIN
a. Descriptor domains:
i. Molecular weights: With a molecular weight of 354.4 g/mol dicresyl phenyl phosphate is within the range of the training set (18.02 - 719.92 g/mol) as well as in the range of the validation set (27.03 - 991.15 g/mol).
ii. Structural fragment domain: Regarding the structure of dicresyl phenyl phosphate, the fragment descriptors found by the program are complete and listed in Appendix D (KOWWIN Fragment and Correction Factor descriptors). Additionally the substance is not listed in Appendix F (Compounds that exceed the Fragment & Molecular Weight Domains).
iii. Mechanism domain: NO INFORMATION AVAILABLE
iv. Metabolic domain, if relevant: NOT RELEVANT
b. Structural analogues: OPTIONAL
i. Considerations on structural analogues: OPTIONAL

6. ADEQUACY OF THE RESULT
a. Regulatory purpose: The data may be used under any regulatory purpose.
b. Approach for regulatory interpretation of the model result: If no experimental data are available, the estimated value is used to fill data gaps needed for hazard and risk assessment, classification and labelling and PBT / vPvB assessment. Further the value can be used for other calculations.
c. Outcome: The prediction of the logarithmic octanol-water partition coefficient yields a useful result for further evaluation.
d. Conclusion: The result is considered as useful for regulatory purposes.

Guideline:

other: REACH guidance QSARs R6, May/July 2008

Deviations:

no

Principles of method if other than guideline:

Estimation Program Interface EPI-Suite version 4.11: KOWWIN for estimating the logarithmic octanol-water partition coefficient (log Kow).
The Estimation Programs Interface was developed by the US Environmental Agency's Office of Pollution Prevention and Toxics and Syracuse Research Corporation (SRC).© 2000 - 2012 U.S. Environmental Protection Agency for EPI SuiteTM (Published online in November 2012).

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

5.8

Remarks on result:

other: Temp. and pH are not reported

Details on results:

SMILES notations of six regioisomeric dicresyl phenyl phosphates were entered in the initial data entry screen, always resulting in the same log Kow.

Validity of model:

1. Defined Endpoint: Octanol-water partition coefficient

2. Unambiguous algorithm:

The molecule is separated into distinct atom/fragments using an Atom/Fragment Contribution method. Based on structure of the molecule, the following fragments were applied: -CH3 (aliphatic carbon), -C- (aromatic carbon), -O-P (aromatic attach) and O=P. The number of times of the fragments that occur in the structure of the substance applied by the program is verified.

3. Applicability domain: With a molecular weight of 354.4 g/mol the substance is within the range of the training set (18.02 - 719.92) as well as in the range of the validation set (27.03 - 991.15).

4. Statistical characteristics: Correlation coefficient of the total training set r² = 0.982; Correlation coefficient of the total validation set r² = 0.943.

5. Mechanistic interpretation: The structural fragments used as descriptors reflect the lipophilic or hydrophobic properties of the substances, and so the octanol-water partition coefficient.

6. Adequacy of prediction: The result for dicresyl phenyl phosphates falls within the applicability domain described above and the estimation rules applied for the substance appears appropriate. Therefore the predicted value can be considered reliable yielding a useful result for further assessment.

Conclusions:

The QSAR determination of the logarithmic octanol-water partition coefficient for dicresyl phenyl phosphates using the model KOWWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 5.80. The predicted value can be considered reliable yielding a useful result for further assessment.

Executive summary:

The logarithmic octanol-water partition coefficient (log Kow) for dicresyl phenyl phosphates was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v 4.11. The log Kow was estimated to be 5.80. The predicted value can be considered reliable yielding a useful result for further assessment.

Reference 4

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

supporting 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
Individual model KOWWIN included in the Estimation Programs Interface (EPI) Suite.

2. MODEL (incl. version number)
KOWWIN v1.68 included in EPISuite v 4.11, ©2000 - 2012

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
A SMILES NOTATION was entered in the initial data entry screen. In the structure window, the molecular weight, structural formula and the structure of the input SMILES notation is shown.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL

a. Defined Endpoint: Octanol-water partition coefficient

b. Explicit algorithm:
The program methodology is known as an Atom/Fragment Contribution (AFC) method. KOWWIN uses a "fragment constant" methodology to predict log P. In a "fragment constant" method, a structure is divided into fragments (atom or larger functional groups) and coefficient values of each fragment or group are summed together to yield the log P estimate.
The equation is as follows: Log Kow = Sum (fini) + Sum (cjnj) + 0.229, where Sum (fini) is the summation of fi (the coefficient for each atom/fragment) times ni (the number of times the atom/fragment occurs in the structure), and (cjnj) is the summation of cj (the coefficient for each correction factor) times nj (the number of times the correction factor occurs (or is applied) in the molecule). The program requires only a chemical structure to estimate a log P. KOWWIN initially separates a molecule into distinct atom/fragments. For various types of structures, that log P estimates made from atom/fragment values alone could or needed to be improved by inclusion of substructures larger or more complex than "atoms"; hence, correction factors were added to the AFC method.

c. Descriptor selection:
As the program requires only a chemical structure to estimate a log P, KOWWIN initially separates a molecule into distinct atom/fragments. Each non-hydrogen atom (e.g. carbon, nitrogen, oxygen, sulfur, etc.) in a structure is a "core" for a fragment; the exact fragment is determined by what is connected to the atom. Several functional groups are treated as core "atoms". Connections to each core "atom" are either general or specific. For example, aromatic carbon, aromatic oxygen and aromatic sulfur atoms have nothing but general connections; i.e., the fragment is the same no matter what is connected to the atom. In contrast, the aliphatic carbon atom does not matter what is connected to -CH3, -CH2-, or -CH<, the fragment is the same; however, an aliphatic carbon with no hydrogens has two possible fragments: (a) if there are four single bonds with 3 or more carbon connections and (b) any other not meeting the first criteria. Additionally, for various types of structures, need to be improved by inclusion of substructures larger or more complex than "atoms" by adding correction factors. The correction factors have two main groupings: first, factors involving aromatic ring substituent positions and second, miscellaneous factors. In general, the correction factors are values for various steric interactions, hydrogen-bondings, and effects from polar functional substructures. Individual correction factors were selected through a tedious process of correlating the differences (between log P estimates from atom/fragments alone and measured log P values) with common substructures.

d. Defined domain of applicability: For each fragment the maximum number of instances of that fragment in any of the 2447 training set compounds and 10946 validation set compounds is located in Appendix D of the help menu of the EPISuite data entry page. The minimum and the maximum values for molecular weight are the following:
Training Set Molecluar Weights: 18.02-719.92 g/mol
Validation Set Molecular Weights: 27.03-991.15 g/mol

e. Statistical characteristics: Correlation coefficient of the total training set r² = 0.982; Correlation coefficient of the total validation set r² = 0.943.
KOWWIN has been tested on an external validation dataset of 10,946 compounds. The validation set includes a diverse selection of chemical structures that rigorously test the predictive accuracy of any model. It contains many chemicals that are similar in structure to chemicals in the training set, but also many chemicals that are different from and structurally more complex than chemicals in the training set. The average molecular weight of compounds in the validation set is 258.98 versus 199.98 for the training set.
(Training dataset includes a total of 2447 compounds)
(Validation dataset includes a total of 10946 compounds)

f. Mechanistic interpretation: The structural fragments used as descriptors reflect the lipophilic or hydrophobic properties of the substances, and so the octanol-water partition coefficient.

5. APPLICABILITY DOMAIN
a. Descriptor domains:
i. Molecular weights: With a molecular weight of 363.4 g/mol the substance is within the range of the training set (18.02 - 719.92 g/mol) as well as in the range of the validation set (27.03 - 991.15 g/mol).
ii. Structural fragment domain: Regarding the structure of tricresyl phosphates, the fragment descriptors found by the program are complete and listed in Appendix D (KOWWIN Fragment and Correction Factor descriptors). Additionally the substance is not listed in Appendix F (Compounds that exceed the Fragment & Molecular Weight Domains).
iii. Mechanism domain: NO INFORMATION AVAILABLE
iv. Metabolic domain, if relevant: NOT RELEVANT
b. Structural analogues: OPTIONAL
i. Considerations on structural analogues: OPTIONAL

6. ADEQUACY OF THE RESULT
a. Regulatory purpose: The data may be used under any regulatory purpose.
b. Approach for regulatory interpretation of the model result: If no experimental data are available, the estimated value is used to fill data gaps needed for hazard and risk assessment, classification and labelling and PBT / vPvB assessment. Further the value can be used for other calculations.
c. Outcome: The prediction of the logarithmic octanol-water partition coefficient yields a useful result for further evaluation.
d. Conclusion: The result is considered as useful for regulatory purposes.

Guideline:

other: REACH guidance QSARs R6, May/July 2008

Deviations:

no

Principles of method if other than guideline:

Estimation Program Interface EPI-Suite version 4.11: KOWWIN for estimating the logarithmic octanol-water partition coefficient (log Kow).
The Estimation Programs Interface was developed by the US Environmental Agency's Office of Pollution Prevention and Toxics and Syracuse Research Corporation (SRC).© 2000 - 2012 U.S. Environmental Protection Agency for EPI SuiteTM (Published online in November 2012).

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Key result

Type:

log Pow

Partition coefficient:

6.34

Remarks on result:

other: Temp. and pH are not reported

Details on results:

SMILES notations of ten regioisomeric tricresyl phosphates were entered in the initial data entry screen, always resulting in the same log Kow.

Validity of model:

1. Defined Endpoint: Octanol-water partition coefficient

2. Unambiguous algorithm: The molecule is separated into distinct atom/fragments using an Atom/Fragment Contribution method. Based on structure of the molecule, the following fragments were applied: -CH3 (aliphatic carbon), -C- (aromatic carbon), -O-P (aromatic attach) and O=P. The number of times of the fragments that occur in the structure of the substance applied by the program is verified.

3. Applicability domain: With a molecular weight of 368.4 g/mol the substance is within the range of the training set (18.02 - 719.92) as well as in the range of the validation set (27.03 - 991.15).

4. Statistical characteristics: Correlation coefficient of the total training set r² = 0.982; Correlation coefficient of the total validation set r² = 0.943.

5. Mechanistic interpretation: The structural fragments used as descriptors reflect the lipophilic or hydrophobic properties of the substances, and so the octanol-water partition coefficient.

6. Adequacy of prediction: The result for tricresyl phosphates falls within the applicability domain described above and the estimation rules applied for the substance appears appropriate. Therefore the predicted value can be considered reliable yielding a useful result for further assessment.

Conclusions:

The QSAR determination of the logarithmic octanol-water partition coefficient for tricresyl phosphates using the model KOWWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed a value of 6.34. The predicted value can be considered reliable yielding a useful result for further assessment.

Executive summary:

The logarithmic octanol-water partition coefficient (log Kow) for tricresyl phosphates was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v 4.11. The log Kow was estimated to be 6.34. The predicted value can be considered reliable yielding a useful result for further assessment.

Description of key information

The logPow value was measured to be 4.5 at 22 °C (equivalent to an octanol/water coefficient of 32000).

Key value for chemical safety assessment

Log Kow (Log Pow):

4.5

at the temperature of:

22 °C

Additional information

The logPow value may refer to the major component of the substance, cresyldiphenyl phosphate (CDP). As the detailed composition of the test material is not clearly stated, the experimental result was validated using QSAR estimations for the substance classes of 'Cresyldiphenyl phosphate, Dicresylphenyl phosphate and Tricresyl phosphate'. As the same logPow was calculated for the respective regioisomeric forms of each class one QPRF is sufficient per substance class. The comparison indicates that the QSAR values are in the same range as the experimental values. The calculated values are in the range of 5.25 to 6.34.