Registration Dossier
Registration Dossier
Diss Factsheets
Use of this information is subject to copyright laws and may require the permission of the owner of the information, as described in the ECHA Legal Notice.
EC number: 201-944-8 | CAS number: 89-83-8
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data

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.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.

EU Privacy Disclaimer
This website uses cookies to ensure you get the best experience on our websites.