Registration Dossier
Registration Dossier
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EC number: - | CAS number: -
Dissociation constant
Administrative data
Link to relevant study record(s)
- Endpoint:
- dissociation constant
- Data waiving:
- study scientifically not necessary / other information available
- Justification for data waiving:
- other:
- Endpoint:
- dissociation constant
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- supporting study
- Study period:
- 15 Nov 2011
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- comparable to guideline study
- Qualifier:
- equivalent or similar to guideline
- Guideline:
- other: SOP 00288 Version 1, corresponding to OECD Guideline 112, adopted May 1981
- GLP compliance:
- yes (incl. QA statement)
- Remarks:
- Ministerium für Umwelt und Naturschutz, Landwirtschaft und Verbraucherschutz des Landes Nordrhein-Westfalen
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 4
- Temp.:
- 20 °C
Referenceopen allclose all
End neutralization point: 9.97 mL/pH 8.66
Half neutralization point: 4.98 mL/pH 4.04
pKa value: 4.00
(Half neutralisation point of the test item = pKa value)
Remark:
With the software ACD/ChemSketch (ACD/Labs 7.00 Release), three values for the dissociation constant were calculated:
pKa (H3L/H+H2L) = 1.31 ± 0.50 (Isomer 2) and 1.68 ± 0.50 (Isomer 1) (Protonation of the NH fuction)
pKa (H2L/H+HL) = 3.57 ± 0.50 (Isomer 2) and 3.93 ± 0.50 (Isomer 1) (deprotonation of the OH-function and protonation of the NH-function)
pKa (HL/H+L) = 4.77 ± 0.19 (both isomers) (deprotonation of the second OH-function)
Due to the limitations of the experimental procedure, only one pKa was found. The titration method is able to measure pKa > 2. The other calculated pKa values are so close that the method cannot discriminate between them. Both pKa values are resolved in one pH-step.
Description of key information
Not applicable.
Key value for chemical safety assessment
Additional information
The substance Reaction mass of dipotassium 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinate and dipotassium 2-(4,5-dimethy-1H-pyrazol-1-yl) succinate is a salt.
The dissociation constant of the 'parent substance' is given as supporting information, the pka of Reaction mass of 2-(3,4-dimethyl-1H-pyrazol-1-yl) succinic acid and 2-(4,5-dimethyl-1H-pyrazol-1-yl) succinic acid was determined according to internal standard operating procedure SOP 00288 v1, corresponding to OECD Guideline 112 (1981). The pka was determined to be 4.0 at 20 °C.
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.
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