Rhodium tris(2-ethylhexanoate)

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

The use of secondary sources of data is acceptable when they are based on a critical evaluation of peer-reviewed data and a consequent selection of a reliable and representative value for the property under investigation. The introduction to Exploring QSAR, Hydrophobic, Electronic and Steric Constants states that it is an extensive compilation of published data. Each record is evaluated and the preferred value is identified for each substance. Therefore, although the method used is not known, the values presented here are acceptable as they are from a reliable secondary source of phys chem. data.

GLP compliance:

not specified

Type of method:

other: Information on the test method is not provided, but the result is taken from a handbook of published data

Partition coefficient type:

octanol-water

Analytical method:

not specified

Type:

log Pow

Partition coefficient:

2.64

Temp.:

20 °C

Remarks on result:

other: temperature not provided, therefore assumed standard

Conclusions:

The log kow of 2-ethylhexanoic acid is 2.64.

Executive summary:

Hansch et al. (1995) is a reliable, peer-reviewed handbook and so can be considered suitable for use for this endpoint. The log kow of 2-ethylhexanoic acid is 2.64.

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:

accepted calculation method

Justification for type of information:

1. SOFTWARE
EPISuite v4.1 (US EPA 2010)

2. MODEL (incl. version number)
KOWWIN v1.68

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CAS: 149-57-5
Substance name: Hexanoic acid, 2-ethyl
SMILES: O=C(O)C(CCCC)CC

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Please see attached QMRF.

5. APPLICABILITY DOMAIN
Currently there is no universally accepted definition of model domain, though property estimates are potentially less accurate for compounds outside the Molecular Weight range of the training set compounds, and/or compounds with more of a given fragment than the maximum for all training set compounds. When interpreting results, it should also be considered whether a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed.

The molecular weight of 2-ethylhexanoic acid is within the range of the training set compounds, and the structure has no functional groups that are not covered by the training set substances.

6. ADEQUACY OF THE RESULT
This prediction was conducted as the registered substance is organometallic and partition coefficient is not relevant for inorganic substances, therefore the partition coefficient prediction has been conducted for the organic component of the substance only. The QSAR predictions is considered to provide a reliable assessment of the partition coefficient of the organic component of the substance.

Please see attached QPRF for further details.

Principles of method if other than guideline:

The partition coefficient was estimated using EPISuite v4.0 (US EPA 2009) using KOWWIN v1.67. KOWWIN uses a "fragment constant" methodology in which 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. Coefficients for individual fragments and groups were derived by multiple regression of 2447 reliably measured log P values. The predictive accuracy of KOWWIN has been tested on an external validation dataset of 10,946 compounds with a diverse selection of chemical structures. Currently there is no universally accepted definition of model domain, though property estimates are potentially less accurate for compounds outside the Molecular Weight range of the training set compounds, and/or compounds with more of a given fragment than the maximum for all training set compounds. When interpreting results, it should also be considered whether a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed.

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

2.96

Temp.:

20 °C

Remarks on result:

other: Predicted value. Temperature not stated, therefore assumed standard.

Type:

log Pow

Partition coefficient:

2.64

Temp.:

20 °C

Remarks on result:

other: Database structure match (Sangster 1993). Temperature not stated, therefore assumed standard.

Type	Number	LogKow fragment description	Coefficient	Value
Fragment	2	-CH3 [aliphatic carbon]	0.5473	1.0946
Fragment	4	-CH2-[aliphatic carbon]	0.4911	1.9644
Fragment	1	-CH [aliphatic carbon]	0.3614	0.3614
Fragment	1	-COOH [acid, aliphatic attach]	-0.6895	-0.6895
Constant	-	Equation constant	0.2290

Conclusions:

The log partition coefficient of hexanoic acid, 2-ethyl- is predicted to be 2.96.

Executive summary:

Partition coefficient was predicted using a QSAR model (KOWWIN v1.68 in EPISuite v4.1, US EPA 2010), following the Atom/Fragment Contribution method. The log partition coefficient of hexanoic acid, 2-ethyl- is predicted to be 2.96.

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:

accepted calculation method

Justification for type of information:

1. SOFTWARE
EPISuite v4.1 (US EPA 2010)

2. MODEL (incl. version number)
KOWWIN v1.68

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
CAS: 104-76-7
Substance name: 1-Hexanol, 2-ethyl-
SMILES: OCC(CCCC)CC

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
Please see attached QMRF.

5. APPLICABILITY DOMAIN
Currently there is no universally accepted definition of model domain, though property estimates are potentially less accurate for compounds outside the Molecular Weight range of the training set compounds, and/or compounds with more of a given fragment than the maximum for all training set compounds. When interpreting results, it should also be considered whether a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed.

The molecular weight of 2-ethylhexanol is within the range of the training set compounds, and the structure has no functional groups that are not covered by the training set substances.

6. ADEQUACY OF THE RESULT
This prediction was conducted as the registered substance is organometallic and partition coefficient is not relevant for inorganic substances, therefore the partition coefficient prediction has been conducted for the organic component of the substance only. The QSAR predictions is considered to provide a reliable assessment of the partition coefficient of the organic component of the substance.

Please see attached QPRF for further details.

Principles of method if other than guideline:

The partition coefficient was estimated using EPISuite v4.0 (US EPA 2009) using KOWWIN v1.67. KOWWIN uses a "fragment constant" methodology in which 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. Coefficients for individual fragments and groups were derived by multiple regression of 2447 reliably measured log P values. The predictive accuracy of KOWWIN has been tested on an external validation dataset of 10,946 compounds with a diverse selection of chemical structures. Currently there is no universally accepted definition of model domain, though property estimates are potentially less accurate for compounds outside the Molecular Weight range of the training set compounds, and/or compounds with more of a given fragment than the maximum for all training set compounds. When interpreting results, it should also be considered whether a compound may have a functional group(s) or other structural features not represented in the training set, and for which no fragment coefficient was developed.

GLP compliance:

no

Type of method:

other: QSAR

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

2.73

Temp.:

20 °C

Remarks on result:

other: Predicted value. Temperature not stated, therefore assumed standard.

Conclusions:

The log partition coefficient of 1-hexanol, 2-ethyl- is predicted to be 2.73.

Executive summary:

Partition coefficient was predicted using a QSAR model (KOWWIN v1.68 in EPISuite v4.1, US EPA 2010), following the Atom/Fragment Contribution method. The log partition coefficient of 1-hexanol, 2-ethyl- is predicted to be 2.73.

Description of key information

Partition coefficient is only relevant for organics, therefore the partition coefficients of 2-ethylhexanoic acid and 2-ethylhexan-1-ol are reported. The log partition coefficient of 2-ethylhexanoic acid is 2.64 - 2.96 and the log partition coefficient of 2-ethylhexan-1-ol is 2.73.

Additional information

Rhodium tris(2-ethylhexanoate) is an organometallic substance. Partition coefficient is not relevant for inorganic substances, therefore the organic component only has been assessed. As this substance is available in two solvents, 2-ethylhexan-1-ol and 2-ethylhexanoic acid, the partition coefficient values for both substances have been reported.

A partition coefficient value for 2-ethylhexanoic acid is available in a handbook of published data. Hansch et al. (1995) is a reliable, peer-reviewed handbook and so can be considered suitable for use for this endpoint. The log kow of 2-ethylhexanoic acid is reported to be 2.64.

The partition coefficients for both substances have also been predicted using a QSAR model (KOWWIN v1.68 in EPISuite v4.1, US EPA 2010), following the atom/fragment contribution method. The log partition coefficient of 2-ethylhexanoic acid is predicted to be 2.96 and the log partition coefficient of 2-ethylhexan-1-ol is predicted to be 2.73.