Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 203-058-7 | CAS number: 102-82-9
Partition coefficient
Administrative data
Link to relevant study record(s)
Description of key information
Log Pow = 3.34 at 25 °C and pH 9.35(measured; Laus, 2010)
pH was measured with 9.35. The following result was obtained: Log Pow = 3.338 ± 0.046 (25 °C; pH 9.35) RSD (relative standard variation) = 1.4%
The draw-back of the study is, that Pow was not determined for each ionisation state (protonated / not protonated):
Given the pKa of tributylamine at 25 °C (10.89) at pH of determination (pH 9.35), approximately 97% will be present as tertiary ammonium ion, while ca. 3% will be in the neutral, non-protonated form.
In consequence, log Kow will be lower than 3.34 in the environmentally relevant neutral pH-range, while the log Kow value for the neutral molecule will be higher and could only be determined at very high pH values (pronouncedly higher than pKa of 10.89 at 25 °C).
This fits with the results determined in the supporting study (BASF
Key value for chemical safety assessment
- Log Kow (Log Pow):
- 3.34
- at the temperature of:
- 25 °C
Additional information
In the reliable (with restrictions) key study (LAUS, 2010), the log Pow was determined for the submission substance tributylamine according to OECD 123 (Slow-Stirring Method) compliant with GLP. pH was measured with 9.35. The following result was obtained:
Log Pow = 3.338 ± 0.046 (25 °C; pH 9.35)
RSD (relative standard variation) = 1.4%
The draw-back of the study is that Pow was not determined for each ionisation state of the ionisable tributylamine: given a pKa at 25°C of 10.89, at pH 9.35 as determined within the study approximately 3% of tributylamine will be present in the neutral state, while ca. 97% will be present as tertiary ammonium ion.
In conclusion, log Pow will be lower in the environmentally relevant neutral pH range around pH 7, while log Pow will be higher for the neutral, non-protonated form. Pow for the latter could only be determined at very high pH-values significantly above pKa.
This fits with the data from the supporting study (BASF, 1988): a lower log Pow of 2.4 at 25°C was determined at the pH of 9.0. Because pH was less alkaline in this study, a higher fraction of tributylamine was protonated (neutral state ca. 1.27%, i.e. less than half the fraction at pH 9.35) and thus log Pow was lower.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
