Registration Dossier
Registration Dossier
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EC number: 910-697-1 | CAS number: -
Dissociation constant
Administrative data
- Endpoint:
- dissociation constant
- Data waiving:
- study technically not feasible
- Justification for data waiving:
- other:
- Justification for type of information:
- JUSTIFICATION FOR DATA WAIVING
In accordance with section 2 of REACh Annex XI, testing may be omitted if it is technically not possible.
According to ECHA endpoint specific guidance on information requirements (R.7a, v5.0, December 2016, §R.7.1.17.4), for complex mixtures containing ionisable components, the assessment of pKa is clearly complicated. Estimation of the representative constituent’s pKa values, if appropriate, should be considered.
As presented under Section 1, the substance is a Reaction mass of three inorganic calcium salts (fluoride, sulfate, and carbonate).
Experimental testing with the reaction mass, according to OECD 112 guideline using a potentiometric titration, spectrophotometric and/or conductivity method, does not seem appropriate because the constituents have a different and/or limited water solubility, and don't have significant chromophoric group(s), thus will absorb very little in the ultra-violet/ visible region of the spectrum.
Calcium fluoride and sulfate will totally dissociate into water, the corresponding ions will not have pKa/pKb in the relevant environmental pH range.
Carbonates salts lead to hydrogeno(bi)carbonate (HCO3(-)) and carbonate (CO3(2-)) species, with pKa respectively 6.35 and 10.33 (as in CRC Handbook of Chemistry and Physics (2009)).
Data source
Materials and methods
Results and discussion
Applicant's summary and conclusion
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