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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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: 203-571-6 | CAS number: 108-31-6
Dissociation constant
Administrative data
Link to relevant study record(s)
- Endpoint:
- dissociation constant
- Type of information:
- other: handbook data or collection of data
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- data from handbook or collection of data
- Qualifier:
- according to guideline
- Guideline:
- other: OECD guideline 105
- GLP compliance:
- yes
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 0.011
- Temp.:
- 25 °C
- Remarks on result:
- other: pH= 1.94
- No.:
- #2
- pKa:
- 0
- Temp.:
- 25 °C
- Remarks on result:
- other: pH= 6.22
- Conclusions:
- Based on the results, the dissociation constant of maleic anhydride (as maleic acid) is 5.95 x 10^-7 (pH = 6.22) at 25 ºC.
- Executive summary:
In a GLP guideline study according to OECD 105, the dissociation constant of maleic anhydride was investigated. As maleic acid hydrolyses rapidly in water, the dissociation constant of maleic anhydride has been determined via its hydrolisation product – maleic acid.
Based on the results, the dissociation constant of maleic anhydride (as maleic acid) is 5.95 x 10^-7 (pH = 6.22) at 25 ºC.
Reference
Water solubility is 407 g/L at 20 °C.
Description of key information
In a GLP guideline study according to OECD 105, the dissociation constant of maleic anhydride was investigated. As maleic acid hydrolyses rapidly in water, the dissociation constant of maleic anhydride has been determined via its hydrolisation product – maleic acid.
Based on the results, the dissociation constant of maleic anhydride (as maleic acid) is 5.95 x 10^-7 (pH = 6.22) at 25 ºC.
Key value for chemical safety assessment
- pKa at 20°C:
- 0
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.
