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Physical & Chemical properties

Dissociation constant

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Description of key information

The dissociation constant of 3-Methylpyrazol was determined using the titrimetric method in an aqueous solution of the test item containing 1 mol/L. The measurements were performed at 20.0 ± 0.1 °C. From the titration curves, one dissociation constant could be determined. The three main determinations showed good correlation.
As a titration using NaOH yielded no points of equivalence, it can be considered that the test item contain no acidic NH.
The test item 3-Methylpyrazol should be considered as base with one proton acceptor unit. The corresponding acid has a pKaof 3.450 ± 0.012 at 20.0 ± 0.1°C.
Therefore, the pKbof 3-Methylpyrazol is stated as 10.550± 0.012 at 20.0 ± 0.1°C.

Key value for chemical safety assessment

pKa at 20°C:
3.45

Additional information

Data obtained from a guideline study according to OECD 112 with GLP and therefore considered reliable without restrictions.