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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Administrative data

Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report date:
2018

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 112 (Dissociation Constants in Water)
GLP compliance:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
potassium;1-(4-chlorophenyl)pyrazol-3-olate
EC Number:
949-316-9
Cas Number:
1965233-46-8
Molecular formula:
C9H6ClN2O*K
IUPAC Name:
potassium;1-(4-chlorophenyl)pyrazol-3-olate
Test material form:
solid
Remarks:
lumps of various sizes

Results and discussion

Dissociating properties:
yes
Dissociation constant
pKa:
8.7
Temp.:
20 °C

Any other information on results incl. tables

Result

pKa = 8.7

Estimated accuracy: ± 0.1

Note:

Only the dissociation constant of the test item (main component) was determined. A strong base was also detected at the first inflection point (EP1).

Step

Volumne of titrant

[ml]

1.    Determination

 

2.    Determination

 

3.    Determination

 

 

 

pH

pKa

pH

pKa

pH

pKa

0

1.80

8.64

8.44

8.65

8.46

8.67

8.46

1

1.90

8.62

8.45

8.62

8.46

8.63

8.47

2

2.00

8.59

8.47

8.59

8.48

8.61

8.48

3

2.10

8.68

8.59

8.70

8.62

8.71

8.62

4

2.20

8.65

8.60

8.66

8.62

8.68

8.63

5

2.30

8.63

8.62

8.64

8.64

8.66

8.64

6

2.40

8.69

8.72

8.71

8.74

8.72

8.74

7

2.50

8.67

8.73

8.68

8.76

8.70

8.76

8

2.60

8.65

8.76

8.66

8.77

8.67

8.77

9

2.70

8.65

8.79

8.71

8.86

8.73

8.87

10

2.80

8.65

8.82

8.69

8.87

8.71

8.88

 

mean of pKa values

8.66

8.68

8.69

standard deviation

0.13

0.14

0.14

pKa (overall average)

8.7 +/- 0.1

Applicant's summary and conclusion