Registration Dossier
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EC number: 238-961-5 | CAS number: 14887-42-4
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:
- From: 23/09/2009 To: 24/09/2009
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Deviations:
- yes
- Remarks:
- The water was freed from carbon dioxide by boiling vigorously for 10 minutes (instead of 5 minutes as described in the study plan). There is presumed to be no effect on the study.
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- EPA OPPTS 830.7370 (Dissociation constants in water)
- Deviations:
- yes
- Remarks:
- The water was freed from carbon dioxide by boiling vigorously for 10 minutes (instead of 5 minutes as described in the study plan). There is presumed to be no effect on the study.
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- 22/11/2005
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 2.752
- Temp.:
- 20 °C
- Remarks on result:
- other: pKa values were calculated at the half-neutralization point. Temperature reported as 20±0.9°C
- No.:
- #2
- pKa:
- 6.96
- Temp.:
- 20 °C
- Remarks on result:
- other: pKa values were calculated at the half-neutralization point. Temperature reported as 20±0.9°C
- Conclusions:
- The pKa values were calculated at the half-neutralization point. There were two pKa values determined.
pKa1= 2.7525 and pKa2=6.960 at 20°C ± 0.9°C.
This study is conducted according to an appropriate guideline and under the conditions of GLP and therefore the study is considered to be acceptable and to adequately satisfy both the guideline requirement and the regulatory requirement as a key study for this endpoint.
Reference
Table 1 - Results for the determination of the pKa value of the Test Item.
Exp. No. |
Amount of test item [mg] |
Volume of water [mL] |
Concentration NaOH [mol/L] |
Temperature [°C] |
Half neutralisation points
|
|
[HP1] |
[HP2] |
|||||
1 |
121.2 |
50.0 |
0.1 |
20.9 |
2.733 |
6.854 |
2 |
121.9 |
50.0 |
0.1 |
20.8 |
2.697 |
6.959 |
3 |
123.8 |
50.0 |
0.1 |
20.9 |
2.780 |
7.024 |
4 |
122.2 |
50.0 |
0.1 |
20.8 |
2.798 |
7.003 |
mean: |
2.7525 |
6.960 |
||||
n: |
4 |
4 |
||||
pKa: |
2.752 |
6.960 |
||||
Description of key information
One key study is available. Study was performed in accordance with OECD TG 112 and under the conditions of GLP.
Key value for chemical safety assessment
Additional information
The pKa values were calculated at the half-neutralization point. There were two pKa values determined at 20°C ± 0.9°C.
pKa1= 2.7525
pKa2=6.960
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