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: 239-590-1 | CAS number: 15541-60-3
- 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:
- calculation (if not (Q)SAR)
- Adequacy of study:
- key study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Literature pKa values for acid and base components reported instead of experimental determination which was technically not possible due to multiplicity of pKa values for each component.
- Qualifier:
- no guideline required
- Principles of method if other than guideline:
- No determination of dissociation constant in water was performed by Method 112 of the OECD Guidelines for Testing of Chemicals, 12 May 1981, due to the availability of literature values for the individual components of the test material. Also, as the test material was a mixture of two components with multiple pKa's, an experimental determination would have proved technically very difficult. Each component had been previously investigated for their dissociating properties and the results reported in respected journals and text books. Journal reported literature values were obtained using the ACD/1-Lab Web service (ACD/pKa DB 7.02).
- GLP compliance:
- yes (incl. QA statement)
- Dissociating properties:
- yes
- No.:
- #1
- pKa:
- 5.16
- Remarks on result:
- other: Organic component (protonation of ring nitrogen)
- No.:
- #2
- pKa:
- ca. 1
- Remarks on result:
- other: Pyrophosphoric acid
- Remarks:
- successive deprotonation of active hydrogen atoms
- No.:
- #3
- pKa:
- ca. 1.8
- Remarks on result:
- other: Pyrophosphoric acid
- Remarks:
- successive deprotonation of active hydrogen atoms
- No.:
- #4
- pKa:
- 6.57
- Remarks on result:
- other: Pyrophosphoric acid
- Remarks:
- successive deprotonation of active hydrogen atoms
- No.:
- #5
- pKa:
- 9.64
- Remarks on result:
- other: Pyrophosphoric acid
- Remarks:
- successive deprotonation of active hydrogen atoms
- Conclusions:
- The organic component (melamine) has one measurable pKa value of 5.16. Pyrophosphoric acid can dissociate by successive deprotonation resulting in four measurable pKa values, of ~1, ~1.8, 6.57 and 9.64.
However it is possible that MPP shows different physico-chemical properties from melamine and pyrophosphate because MPP is not inorganic salt of melamine or pyrophosphate but organic salt constituted by both of them. And according to these differences, it may also show different environmental and metabolic pathway from melamine and pyrophosphate. Therefore, dissociation constant will be conducted by MPP itself and its result will be used for conclusion.
Reference
The following references were found:
(1) pKa of melamine - Albert A., Goldacre R., and Phillips J. N., J. Chern. Soc., 1948, 2240
(2) pKa of pyrophosphoric acid - Greenwood N. N., and Earnshaw A., Chemistry of the Elements, Butterworth-Heinemann, Oxford, 2001.
Description of key information
The organic component has one measurable pKa value of 5.16. The inorganic component, pyrophosphoric acid, can dissociate by successive deprotonation resulting in four measurable pKa values, of ~1, ~1.8, 6.57 and 9.64
Key value for chemical safety assessment
Additional information
Read-across from supporting substances melamine and pyrophosphate
However it is possible that MPP shows different physico-chemical properties from melamine and pyrophosphate because MPP is not inorganic salt of melamine or pyrophosphate but an organic salt constituted by both of them. And according to these differences, it may also show different environmental and metabolic pathway from melamine and pyrophosphate. Therefore, dissociation constant will be conducted by MPP itself and its result will be used for conclusion.
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.