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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Link to relevant study record(s)

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Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Principles of method if other than guideline:
Data from peer reviewed handbook. No data provided on methods.
GLP compliance:
not specified
Dissociating properties:
yes
No.:
#1
pKa:
6.9
Temp.:
20 °C
Conclusions:
The pKa of the test item at 20ºC is 6.9.
Executive summary:

According to the Kirk-Othmer Encyclopedia of Chemical Technology (peer reviewed handbook data), the pKa of the test item at 20ºC is 6.9.

Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1971.
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 112 (Dissociation Constants in Water)
Version / remarks:
Spectrophotometric method.
Principles of method if other than guideline:
Spectophotometric determination of acid-base concentration ratios.
GLP compliance:
no
Dissociating properties:
yes
No.:
#1
pKa:
6.71
Temp.:
25 °C
Remarks on result:
other: mono (BH+)
No.:
#2
pKa:
-7.65
Temp.:
25 °C
Remarks on result:
other: di (BH2,2+)
Conclusions:
The pKa of the test item was determined to be 6.71.
Executive summary:

The pKa of the test item was determined spectrophotometrically, by a method similar to OECD 112 (no GLP). The pKa of the test item was determined to be 6.71.

Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Principles of method if other than guideline:
Data from peer reviewed handbook. No data provided on methods.
GLP compliance:
not specified
Dissociating properties:
yes
No.:
#1
pKa:
6.82
Temp.:
20 °C
Conclusions:
The pKa of the test item at 20ºC is 6.82.
Executive summary:

According to the CRC Handbook of Chemistry and Physics (peer reviewed handbook data), the pKa of the test item at 20ºC is 6.82.

Description of key information

Weight of evidence. Based on the results of a study by a method similar to OECD 112 (non-GLP), and data from peer reviewed handbooks, the pKa of the test item is 6.8 at 20ºC.

Key value for chemical safety assessment

pKa at 20°C:
6.71

Additional information

The following information was available for the test item: In a study by Bellobono (1971), the pKa of the test item was determined spectrophotometrically, by a method similar to OECD 112 (no GLP); the pKa of the test item was determined to be 6.71. According to the Kirk-Othmer Encyclopedia of Chemical Technology (peer reviewed handbook data), the pKa of the test item at 20ºC is 6.9. According to the CRC Handbook of Chemistry and Physics (peer reviewed handbook data), the pKa of the test item at 20ºC is 6.82.