Registration Dossier
Registration Dossier
Data platform availability banner - registered substances factsheets
Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.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.
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: 209-813-7 | CAS number: 593-85-1
- 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)
Description of key information
Guanidine carbonate gets dissolved in the Guanidinium kation and the Carbonate. While the equilibrium of the Carbonate species will in the environmental range strongly depend on the actual pH, the Guanidine equilibrium will be about 100 % on the side of the Guanidinium kation according to the guanidine pKa value given below.
Key value for chemical safety assessment
- pKa at 20°C:
- 12.5
Additional information
- Budaravi S ed (1996). The Merck Index. An Encyclopedia of Chemicals, Drugs, and Biologicals, 12th edition. ISBN 0911910-12-3 New York, NJ, U.S.A., Merck
- ECHA European Chemicals Agency (2012).Guidance on information requirements and chemical safety assessment Chapter R.7a: Endpoint specific guidance, FIRST DRAFT FOR PEG, 2nd March 2012, Guidance for the implementation of REACH. Self-published. 167 p
- Holleman AF, Wiberg N (2007). Lehrbuch der Anorganischen Chemie. 102. Auflage, de Gruyter, Berlin, Germany. ISBN 978-3-11-017770-1
- OECD Organisation for Economic Co-operation and Development (2004). Hydrolysis as function of pH. Self-published (OECD Publishing). ISSN 2074-5753 (online) ISBN 9789264069701 (PDF) doi: 10.1787/9789264069701-en OECD Guideline for the Testing of Chemicals, Section 1, Test No. 111, adopted 13th April 2004.15 p
The dissociation constant of the submission item Guanidine carbonate was determined according to the OECD TG 112 protocol by titration (Reuse 2009). 2.5 g of Guanidine carbonate were dissolved in 200 g of distillate water. Hydrochloric acid (CAS 7647-01-0) 1M was added continuously under stirring and the pH-value was measured. It was possible to distinguish two contributions of Guanidine carbonate to the pH-curve. The inflexion point is reached for pH-values of 6.1 and 2.5. The report concludes therefore on dissociation constants pKb1 = 7.9 and pKb2 = 11.5. The author did not draw any conclusion on the assignment of these values to dissociated species. The applied titration method suffers from possible Carbon dioxide (CAS 124-38-9) formation and release. The addition of Hydrochloric acid effects simultaneous protonation of Guanidine (CAS 113-00-8), Carbonate (CAS 3812-32-6) and Hydrogen carbonate (CAS 71-52-3). In consequence the measured values are of little relevance for the chemical safety assessment.
According to Holleman & Wiberg (2007) the pKa values for the carbonic acid are 6.35 for the formation of Hydrogen carbonate from Carbon dioxide (plus two water molecules) and 10.33 for the formation of Carbonate from Hydrogen carbonate (plus one water molecule). It seems that the results of Reuse (2009) are significantly influenced by carbonate, which is deemed not relevant for the chemical safety assessment of Guanidine carbonate.
As the relevant part of the solute Guanidine carbonate is considered to be Guanidine, its pKa of ca. 12.5 (Budaravi 1996) should be reported here. This value indicates that under environmental conditions and in body fluids Guanidine is present solely in the form of the Guanidinium kation. The dissociation behaviour of this species expressed by the pKa ca. 12.5 is thus the key value for assessment.
In summary the submission item Guanidine carbonate gets dissolved in the Guanidinium kation and the Carbonate. Both moieties equilibrate then according to the given pKa values. While the equilibrium of the carbonate species will in the environmental pH range (5-9 according to page 69 of ECHA 2012 or 4-9 according to page 1 of OECD TG 111) strongly depend on the actual pH, the guanidine equilibrium will be on the side of the Guanidinium kation, which represents 100 % at pH 4, 99.97 % at pH 9 and 99.75 % at pH 10.
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.