Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

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:
experimental study
Adequacy of study:
key study
Study period:
Up to 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline, Information from published handbook, acceptable with restrictions.
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
Remarks:
No data reported
Type of method:
other: No data reported
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
2.89
Temp.:
20 °C
pH:
7
Remarks on result:
other: Temperature and pH not reported so assumed to be standard temperature and neutral pH
Details on results:
No data reported

N/A

Conclusions:
The log pow of butane is 2.89.
Executive summary:

The log pow of butane is 2.89. This information is taken from a reliable peer reviewed handbook and so can be considered reliable and suitable for use as the key study for this endpoint.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2008
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR calculation, acceptable with restrictions
Justification for type of information:
QSAR prediction
Principles of method if other than guideline:
KOWWIN uses a fragment constant methodology known as an Atom/Fragment Contribution (AFC) to predict log P.  A chemical 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.
GLP compliance:
no
Type of method:
other: QSAR calculation
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
SMILES used as input for the calculation:

Butane: CCCC

Key result
Type:
log Pow
Partition coefficient:
2.306
Temp.:
20 °C
pH:
7
Remarks on result:
other: Standard temperature and pH assumed
Details on results:
Data calculated based on butane structure

The substance is within the range of physicochemical properties allowed by KOWWIN and all its fragments are represented in the training set of the model, therefore the prediction is considered within domain.

Conclusions:
The calculated log Kow of butane is 2.3.
Executive summary:

The use of a QSAR, KOWWIN, to predict the log Kow for Butane is an appropriate technique to use as the structure of the substance is within the model domain. The calculated log Kow for Butane is 2.3.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Up to 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline, Information from published handbook, acceptable with restrictions.
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
Remarks:
No data reported
Type of method:
other: No data reported
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
N/A
Key result
Type:
log Pow
Partition coefficient:
1.81
Temp.:
20 °C
pH:
7
Remarks on result:
other: Temperature and pH not reported so assumed to be standard temperature and neutral pH
Details on results:
No data reported

N/A

Conclusions:
The log pow of ethane is 1.81.
Executive summary:

The log pow of ethane is 1.81. This information is taken from a reliable peer reviewed handbook and so can be considered reliable and suitable for use as the key study for this endpoint.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2008
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR calculation, acceptable with restrictions
Justification for type of information:
QSAR prediction
Principles of method if other than guideline:
KOWWIN uses a fragment constant methodology known as an Atom/Fragment Contribution (AFC) to predict log P.  A chemical 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.
GLP compliance:
no
Type of method:
other: QSAR calculation
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
SMILES used as input for the calculation:

Ethane: CC
Key result
Type:
log Pow
Partition coefficient:
1.324
Temp.:
20 °C
pH:
7
Remarks on result:
other: Standard temperature and pH assumed
Details on results:
Data calculated based on ethane structure

The substance is within the range of physicochemical properties allowed by KOWWIN and all its fragments are represented in the training set of the model, therefore the prediction is considered within domain.

Conclusions:
The calculated log Kow of ethane is 1.32.
Executive summary:

The use of a QSAR, KOWWIN, to predict the log Kow for Ethane is an appropriate technique to use as the structure of the substance is within the model domain. The calculated log Kow for Ethane is 1.32.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2008
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline, Information from published handbook, acceptable with restrictions.
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: Not specified
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
N/A
Key result
Type:
log Pow
Partition coefficient:
2.8
Temp.:
20 °C
pH:
7
Details on results:
Temperature and pH not reported so assumed to be standard temperature and neutral pH

N/A

Conclusions:
The log Kow of isobutane is 2.8
Executive summary:

The data were taken from a peer reviewed handbook which is deemed to be reliable. The log Kow of isobutane is 2.8

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Up to 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline, Information from published handbook, acceptable with restrictions.
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
Remarks:
No data reported
Type of method:
other: No data reported
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
N/A
Key result
Type:
log Pow
Partition coefficient:
2.76
Temp.:
20 °C
pH:
7
Remarks on result:
other: Temperature and pH not reported so assumed to be standard temperature and neutral pH
Details on results:
No data reported

N/A

Conclusions:
The log pow of isobutane is 2.76.
Executive summary:

The log pow of isobutane is 2.76. This information is taken from a reliable peer reviewed handbook and so can be considered reliable and suitable for use as the key study for this endpoint.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2008
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR calculation, acceptable with restrictions
Justification for type of information:
QSAR prediction
Principles of method if other than guideline:
KOWWIN uses a fragment constant methodology known as an Atom/Fragment Contribution (AFC) to predict log P.  A chemical 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.
GLP compliance:
no
Type of method:
other: QSAR calculation
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
SMILES used as input for the calculation:

Isobutane: CC(C)C
Key result
Type:
log Pow
Partition coefficient:
2.232
Temp.:
20 °C
pH:
7
Remarks on result:
other: Standard temperature and pH assumed
Details on results:
Data calculated based on isobutane structure

The substance is within the range of physicochemical properties allowed by KOWWIN and all its fragments are represented in the training set of the model, therefore the prediction is considered within domain

Conclusions:
The calculated log Kow of isobutane is 2.23.
Executive summary:

The use of a QSAR, KOWWIN, to predict the log Kow for Isobutane is an appropriate technique to use as the structure of the substance is within the model domain. The calculated log Kow for Isobutane is 2.23

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Up to 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline, Information from published handbook, acceptable with restrictions.
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
Remarks:
No data reported
Type of method:
other: No data reported
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
N/A
Key result
Type:
log Pow
Partition coefficient:
1.09
Temp.:
20 °C
pH:
7
Remarks on result:
other: Temperature and pH not reported so assumed to be standard temperature and neutral pH
Details on results:
No data reported

N/A

Conclusions:
The log pow of methane is 1.09.
Executive summary:

The log pow of methane is 1.09. This information is taken from a reliable peer reviewed handbook and so can be considered reliable and suitable for use as the key study for this endpoint.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2008
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR calculation, acceptable with restrictions
Justification for type of information:
QSAR prediction
Principles of method if other than guideline:
KOWWIN uses a fragment constant methodology known as an Atom/Fragment Contribution (AFC) to predict log P.  A chemical 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.
GLP compliance:
no
Type of method:
other: QSAR calculation
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
SMILES used as input for the calculation:

Methane: C
Key result
Type:
log Pow
Partition coefficient:
0.776
Temp.:
20 °C
pH:
7
Remarks on result:
other: Standard temperature and pH assumed
Details on results:
Data calculated based on methane structure

The substance is within the range of physicochemical properties allowed by KOWWIN and all its fragments are represented in the training set of the model, therefore the prediction is considered within domain.

Conclusions:
The calculated log Kow of methane is 0.78.
Executive summary:

The use of a QSAR, KOWWIN, to predict the log Kow for Methane is an appropriate technique to use as the structure of the substance is within the model domain. The calculated log Kow for Methane is 0.78.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
key study
Study period:
Up to 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP, non-guideline, Information from published handbook, acceptable with restrictions.
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
Remarks:
No data reported
Type of method:
other: No data reported
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
N/A
Key result
Type:
log Pow
Partition coefficient:
2.36
Temp.:
20 °C
pH:
7
Remarks on result:
other: Temperature and pH not reported so assumed to be standard temperature and neutral pH
Details on results:
No data reported

N/A

Conclusions:
The log pow of propane is 2.36.
Executive summary:

The log pow of propane is 2.36. This information is taken from a reliable peer reviewed handbook and so can be considered reliable and suitable for use as the key study for this endpoint.

Endpoint:
partition coefficient
Type of information:
(Q)SAR
Adequacy of study:
key study
Study period:
2008
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: QSAR calculation, acceptable with restrictions
Justification for type of information:
QSAR prediction
Principles of method if other than guideline:
KOWWIN uses a fragment constant methodology known as an Atom/Fragment Contribution (AFC) to predict log P.  A chemical 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.
GLP compliance:
no
Type of method:
other: QSAR calculation
Partition coefficient type:
octanol-water
Specific details on test material used for the study:
SMILES used as input for the calculation:

Propane: CCC
Key result
Type:
log Pow
Partition coefficient:
1.815
Temp.:
20 °C
pH:
7
Remarks on result:
other: Standard temperature and pH assumed
Details on results:
Data calculated based on propane structure

The substance is within the range of physicochemical properties allowed by KOWWIN and all its fragments are represented in the training set of the model, therefore the prediction is considered within domain.

Conclusions:
The calculated log Kow of propane is 1.8.
Executive summary:

The use of a QSAR, KOWWIN, to predict the log Kow for Propane is an appropriate technique to use as the structure of the substance is within the model domain. The calculated log Kow for Propane is 1.8

Description of key information

The partition coefficient of the substances in the category ranges from 1.09 to 2.89.

Key value for chemical safety assessment

Log Kow (Log Pow):
2.52
at the temperature of:
20 °C

Additional information

Data from Hansch (1995) were available for the substances methane, ethane, propane, butane and isobutane. Data from the CRC handbook (Lide 2008) were available for isobutane. The information is taken from reliable peer reviewed handbooks and so can be considered reliable and suitable for use for this endpoint. QSAR estimate data are also available for methane, ethane, propane, butane and isobutane.

The partition coefficient of methane is 1.09, ethane is 1.81, propane is 2.36, butane is 2.89 and isobutane is 2.76. The mean of the partition coefficient values for the category is 2.52 and this has been used to complete the 'key value for chemical safety assessment'.