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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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

Reference
Endpoint:
dissociation constant
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: well performed and documented publication
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 112 (Dissociation Constants in Water)
Principles of method if other than guideline:
Potentiometric titration
GLP compliance:
no
Specific details on test material used for the study:
Reagent grade, used without further purification
Dissociating properties:
no
No.:
#1
pKa:
15.1
Temp.:
25 °C
Remarks on result:
other: +/- 0.3

Data on pKa derived according to approach 1 (see above - value determined for 1,3-butanediol: 15.5 +/- 0.5) and approach 2 (see above - value determined for 1,3-butanediol: 14.8 +/- 0.2) were used to derive a so-called "best value" for acid ionisation constant pKa.

"Best value" for pKa derived for 1,3-butanediol:

pKa 15.1 (+/- 0.3)

Conclusions:
Acid ionisation constant pKa (potentiometric method, published result): 15.1 (+/- 0.3)
Executive summary:

The acid ionisation constant pKa was determined in a reliable well-documented published study using potentiometric titration. Two different approaches led to pKa values very close to each other.

Approach 1: pKa 15.5 +/- 0.5

Approach 2: pKa 14.8 +/- 0.2

These results were used to derive a so-called "best value" for acid ionisation constant pKa.

"Best value" for pKa derived for 1,3-butanediol: pKa 15.1 (+/- 0.3)

Concluding, 1,3-butanediol is of very low acidity. The pKa value is in the range of pure water. It must therefore be considered to be non-dissociated under relevant environmental conditions.

Description of key information

Dissociation constant pKa (acidic; potentiometric method): 15.1

Key value for chemical safety assessment

pKa at 20°C:
15.1

Additional information

The acid ionisation constant pKa was determined in a reliable well-documented published study using potentiometric titration. Two different approaches led to pKa values very close to each other.

Approach 1: pKa 15.5 +/- 0.5

Approach 2: pKa 14.8 +/- 0.2

These results were used to derive a so-called "best value" for acid ionisation constant pKa.

"Best value" for pKa derived for 1,3-butanediol: pKa 15.1 (+/- 0.3)

Concluding, 1,3-butanediol is of very low acidity. The pKa value is in the range of pure water. It must therefore be considered to be non-dissociated under relevant environmental conditions.