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EC number: 201-944-8 | CAS number: 89-83-8
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:
- data from handbook or collection of data
- Reason / purpose for cross-reference:
- reference to other study
- Principles of method if other than guideline:
- Measurements of pH changes during titrations using glass electrodes
- GLP compliance:
- not specified
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 10.62
- Temp.:
- 20 °C
- Conclusions:
- The dissociation constant (pKa) of thymol is 10.62 at 20°C. Therfore thymol is mainly present as undissoicated form under environmentally relevant pH (5 -9)
- Executive summary:
In "IUPAC chemical data series, no. 23" Serjeant & Dempsey published in 1979 with "International Union of Pure and Applied Chemistry, Analytical Chemistry Division Commission on Equilibrium Data" ionisation constants of organic acids in aqueous solution.
The dissociation constant (pKa) of thymol is 10.62 at 20°C. Therefore, thymol is mainly present as undissociated form under environmentally relevant pH (5 -9).
Reference
Description of key information
In "IUPAC chemical data series, no. 23" Serjeant & Dempsey published in 1979 with "International Union of Pure and Applied Chemistry, Analytical Chemistry Division Commission on Equilibrium Data" ionisation constants of organic acids in aqueous solution.
The dissociation constant (pKa) of thymol is 10.62 at 20°C. Therfore thymol is mainly present as undissociated form under environmentally relevant pH (5 -9).
Key value for chemical safety assessment
- pKa at 20°C:
- 10.62
Additional information
The above mentioned value is also listed in the Beilstein database (supporting study) which serves as proof for its reliability.
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