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Physical & Chemical properties

Dissociation constant

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Reference
Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1996-10-23 - 1996-10-23 (experimental phase)
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:
no
GLP compliance:
yes
Dissociating properties:
yes
No.:
#1
pKa:
3.55
Temp.:
20 °C
Remarks on result:
other: (basic dissociation constant)

Extrapolated from measurements in water with 20, 30 and 40 % ethanol, since the test substance is only sparingly soluble in water.

In aqueous solution the neutral from of the substance is predominantly present at pH >3.55, the protonic form at pH <3.55.

Conclusions:
The study is considered to be adequate and reliable.
Executive summary:

pKa at 20 °C: 3.55 (basic dissociation constant)

In aqueous solution the neutral from of the substance is predominantly present at pH >3.55, the protonic form at pH 3.55.

Description of key information

pKa (Jäkel, 20 °C, basic): 3.55

Key value for chemical safety assessment

pKa at 20°C:
3.55

Additional information

A guideline study is available which is considered to be reliable and adequate, and is carried forward for use in risk assessment, classification and labelling.