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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

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:
12.06.2003
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP - 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:
ca. 4.03
Temp.:
20 °C
Remarks on result:
other: first carboxyl group
No.:
#2
pKa:
ca. 4.87
Temp.:
20 °C
Remarks on result:
other: second carboxyl group

The dissociation constant was estimated in 3 measurements and the results are shown in the Table:

Measurement

Measurement values

pK1

pK2

1st

4.04

4.03

4.88

4.87

2nd

4.05

4.87

3rd

4.01

4.86

 

Conclusions:
The dissociation constants of the carboxyl groups were determined to be: pKa1 = 4.03, pKa2 = 4.87 (OECD TG 112).

Description of key information

The dissociation constants of the carboxyl groups were determined to be: pKa1 = 4.03, pKa2 = 4.87 (OECD TG 112).

Key value for chemical safety assessment

Additional information