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Partition coefficient

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Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP status and guideline unknown; Information from published handbook, data compendium, review article or other reference text; 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 Canadian National Committee for CODATA database contains evaluated log Kow values and is cited in the ECHA R7a guidance document (2012). Therefore although the guideline followed 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:
HPLC method
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
3.42
Remarks on result:
other: No further details provided such as temp and pH

No further details provided such as temperature and pH.

Conclusions:
Log Kow of mesitylene (1,3,5-trimethylbenzene) was measured to be 3.42; the source states this is the preferred value.
Executive summary:

This information is taken from a reliable peer reviewed database and so can be considered reliable and suitable for use for this endpoint.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP status and guideline unknown; Information from published handbook, data compendium, review article or other reference text; 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 the CRC Handbook of Chemistry and Physics states that data for physical constants have been taken from many sources, including both compilations and the primary literature. Where conflicts were found, the value deemed most reliable was chosen. 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
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
3.42
Remarks on result:
other: No further details provided such as temperature and pH.

No further details provided such as temperature and pH.

Conclusions:
Log Kow of mesitylene (1,3 ,5-trimethylbenzene) was measured to be 3.42.
Executive summary:

No information on the methods used is available. However, this information is taken from a reliable peer reviewed handbook and so can be considered reliable and suitable for use for this endpoint. Log Kow of mesitylene (1,3,5-trimethylbenzene) was measured to be 3.42.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP status and guideline unknown; Information from published handbook, data compendium, review article or other reference text; 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 Canadian National Committee for CODATA database contains evaluated log Kow values and is cited in the ECHA R7a guidance document (2012). Therefore although the guideline followed 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:
shake-flask method to: flask method
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
3.84
Remarks on result:
other: No further details provided such as temperature and pH.

No further details provided such as temperature and pH.

Conclusions:
Log Kow of mesitylene (1,3,5-trimethylbenzene) was measured to be 3.84.
Executive summary:

This information is taken from a reliable peer reviewed database and so can be considered reliable and suitable for use for this endpoint.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP status and guideline unknown; Information from published handbook, data compendium, review article or other reference text; acceptable with restrictions.
Principles of method if other than guideline:
ECHA R7a (2008) states that “Ample of scientific publications and QSAR development studies report measured log Kow values for a variety of chemicals that have been used in the training- or validation sets”. Hansch et al (1995) is used to provide measured log Kow values for the training data set in the EPIWEB KOWWIN QSAR for this substance . As this QSAR programme is widely accepted by Regulators, we believe the use of this data in the training set confirms its reliability.
GLP compliance:
not specified
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
3.42
Remarks on result:
other: No further details provided such as temperature and pH.

Preferred value as/or converted to the neutral form. No further details provided such as temperature and pH.

Conclusions:
Log Kow of mesitylene (1,3,5-trimethylbenzene) was measured to be 3.42.
Executive summary:

This information is taken from the training set of a a reliable QSAR for calculating log Kow and so can be considered reliable and suitable for use for this endpoint. The Log Kow of mesitylene (1,3,5-trimethylbenzene) was reported to be 3.42.

Endpoint:
partition coefficient
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP status and guideline unknown; Information from published handbook, data compendium, review article or other reference text; 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
Partition coefficient type:
octanol-water
Key result
Type:
log Pow
Partition coefficient:
3.42
Remarks on result:
other: No further details provided such as temperature and pH.

Preferred value as/or converted to the neutral form. No further details provided such as temperature and pH.

Conclusions:
Log Kow of mesitylene (1,3,5-trimethylbenzene) was measured to be 3.42; the source states this is the preferred value.
Executive summary:

This information is taken from a reliable peer reviewed handbook and so can be considered reliable and suitable for use for this endpoint. The Log Kow of mesitylene (1,3,5-trimethylbenzene) was measured to be 3.42; the source states this is the preferred value.

Description of key information

The Log Kow of mesitylene (1,3,5-trimethylbenzene) was measured to be 3.42.

Key value for chemical safety assessment

Log Kow (Log Pow):
3.42
at the temperature of:
20 °C

Additional information

Partition coefficient values for this substance are cited in a number of reliable, peer-reviewed secondary data sources. A weight of evidence approach has been used to fill this endpoint based on the data from these secondary sources. A log Kow value of 3.42 is cited in Hansch (1995), Lide (2008) and has been selected as the recommended value in the CODATA database (Pomona College, 1987, cited in CODATA database). This same value taken from Hansch (1995) is also used in the training data set of the USEPA KOWWIN QSAR (USEPA 2008). As this QSAR is widely accepted by Regulators, we believe this demonstrates that the data used to develop the model should also be considered reliable. It is likely that these four data sources are all citing the same original study, and are therefore not independent of each other. However, as each of the four is considered to be an authoritative data source we believe that the use of this data point is justifiable to fulfil this data requirement. A log Kow value of 3.84 is also included in the CODATA database (Hammers et al 1982, cited in CODATA database).

The reported log Kow values of 3.42 and 3.84 are similar to each other, and do not span any criteria used to define the appropriate classification of the substance or its bioaccumulation potential. As the log Kow value of 3.42 is identified as the recommended value in the CODATA database this is taken forward as the key value in the risk assessment.