Registration Dossier
Registration Dossier
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.
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: 701-365-5 | CAS number: -
Dissociation constant
Administrative data
Link to relevant study record(s)
- Endpoint:
- dissociation constant
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Study period:
- 2000
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Reason / purpose for cross-reference:
- read-across source
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- GLP compliance:
- no
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- > 1 - < 2.89
- Temp.:
- 22 °C
- Remarks on result:
- other: for the acid range
- No.:
- #2
- pKa:
- > 8 - < 10
- Temp.:
- 22 °C
- Remarks on result:
- other: alkaline range
- Conclusions:
- The dissociation constant of the test substance at room temperature (ca. 22 °C) was determined within this study as pKa between 1.90 and 2.89 for the acid range, using the five mean values of three experiments.
The pKa value for the alkaline range was determined within this study as pKa between 8.93 and 10.16 based on five mean values obtained from of three experiments. - Executive summary:
The determination of the pKa in the acid and alkaline range was carried out according to the OECD Guideline no. 112.
The dissociation constant of the test substance at room temperature (circa 22 °C) was determined within this study as pKa between 1.90 and 2.89 for the acid range, using the five mean values of three experiments.
The pKa value for the alkaline range was determined within this study as pKa between 8.93 and 10.16 based on five mean values obtained from of three experiments.
Reference
Description of key information
pKa at 20 °C: 1.9 to 2.89
The read across substance bears nearly the same functional groups as the reference substance (the naphthalene moiety bearing two SO3Na-groups and two parabaseester moieties). The only difference is an additional triazine moiety in the red dye. Hence, it is very likely that reference substance and the read across substance have nearly the same pKa values. For "pKa at 20 °C" we give the value in the acidic range, because at basic conditions the dye will be mostly present in its vinyl-sulfone mode.
Key value for chemical safety assessment
- pKa at 20°C:
- 2
Additional information
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.
