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EC number: 203-529-7 | CAS number: 107-88-0
Dissociation constant
Administrative data
Link to relevant study record(s)
- 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
- 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.
Reference
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)
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.
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