Registration Dossier
Registration Dossier
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EC number: 203-699-2 | CAS number: 109-73-9
Dissociation constant
Administrative data
Link to relevant study record(s)
- Endpoint:
- dissociation constant
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- Study initiation date: 24 June 2009 Study completion date: 12 October 2009
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Version / remarks:
- adopted on 12 May 1981
- Deviations:
- no
- GLP compliance:
- yes
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 10.8
- Temp.:
- 23.5 °C
- Remarks on result:
- other: pKa for alkaline functional group
- Remarks:
- based on 2 replicate experiments
- Conclusions:
- Dissociation constant (at 23.5 °C; OECD 112): pKb = 10.8 (i.e. pKa for alkaline functional group)
- Executive summary:
The dissociation constant of the test item was determined compliant with GLP according to OECD guideline no. 112 [adopted on 12 May 1981] with the titration method. Dissociation constant from duplicate determinations (at 23.5 °C): pKb = 10.8 (i.e. pKa for alkaline functional group).
Reference
Details on measurements:
First run:
pH: 11.4
pKa: 10.77
Second run:
pH: 11.4
pKa: 10.76
Mean value of pKa: 10.8 (for alkaline functional group)
Description of key information
pka (OECD 112): 10.8 at 23.5°C (for alkaline functional group)
Key value for chemical safety assessment
- pKa at 20°C:
- 10.8
Additional information
The dissociation constant of the test item was determined compliant with GLP according to OECD guideline no. 112 [adopted on 12 May 1981] with the titration method. Dissociation constant from duplicate determinations (at 23.5 °C) for n-butylamine: pKb = 10.8 (i.e. pKa for alkaline functional group).
This result is corroborated from reliable (RL 2) supporting data (Koelzer and Büchi, 1971):
In this work, the pKa for n-butylamine was determined experimentally from 10 replicate experiments:
pKa (20 °C): 10.65; n= 10; standard deviation (SD) = 0.0091)
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