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Diss Factsheets
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EC number: 206-108-6 | CAS number: 301-10-0
- 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:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 112 (Dissociation Constants in Water)
- Version / remarks:
- and OPPTS 830.7370
- Deviations:
- not specified
- GLP compliance:
- yes
- Dissociating properties:
- yes
- pKa:
- 5.09
- Temp.:
- 20 °C
- Conclusions:
- The pKa value of tin bis(2 -ethylhexanoate) was determined to be 5.09 (SD 0.0337, CV = 0.662%) at 20 °C. The pKa values for phosphoric acid were 2.52 and 7.10 at 20 deg C. The pKa value for 4-nitrophenol was 7.16. The reference substance data were in good agreemant with the literature values.
Experimental Termination date- June 25, 2002 - Executive summary:
The objective of this study was to determine the dissociation constant(s) of tin bis(2 -ethylhexanoate) in water at 20 °C according to OECD Guideline 112 and GLP. The titration method was used to determine the dissiciation constant K (expressed as its log value, pK) of Stannous 2-ethylhaxanoate in water. Phosphoric acid and 4 nitrophenol were used as reference substances. The pKa value of tin bis(2 -ethylhexanoate) was determined to be 5.09 (SD 0.0337, CV = 0.662%) at 20 °C. This indicates that essentially complete dissociation of the test substance will occur at environmentally-relevant pH (i.e., 99% dissociated at pH > 6.8)
Reference
The pKa values for phosphoric acid were 2.52 and 7.10 at 20 °C
The pKa value for 4-nitrophenol was 7.16. The pKa values for the reference substances were in good agreement with published literature values. The mean (n = 3) pKa value for tin (II) ethylhexanoate was determined to be 5.09 (SD = 0.0337, CV - 0.662%) at 20°C. These results are consistent with a reported pKa value of 4.8 for 2 -ethyl hexanoic acid, and indicate that essentially complete dissociation of the test substance will occur at environmentally-relevant pH (i.e., 99% dissociated at pH > 6.8).
Description of key information
The objective of this study was to determine the dissociation constant(s) of tin bis(2 -ethylhexanoate) in water at 20 °C according to OECD Guideline 112 and GLP. The titration method was used to determine the dissiciation constant K (expressed as its log value, pK) of Stannous 2-ethylhaxanoate in water. Phosphoric acid and 4 nitrophenol were used as reference substances. The pKa value of tin bis(2 -ethylhexanoate) was determined to be 5.09 (SD 0.0337, CV = 0.662%) at 20 °C. This indicates that essentially complete dissociation of the test substance will occur at environmentally-relevant pH (i.e., 99% dissociated at pH > 6.8)
Key value for chemical safety assessment
- pKa at 20°C:
- 5.09
Additional information
The pKa of tin bis(2 -ethylhexanoate) was measured according to OECD Guideline 112. The procedure deviated somewhat from the guideline, as the test material is an ionic salt and not in a free-acid or free-base form. Therefore, the measurement could have been confounded by concurrent dissociation of various forms of Sn(II) resulting from dissociation of the salt in the test medium.
Tin bis(2 -ethylhexanoate) is known to readily dissociate upon mixing in water, and various studies have shown that Sn(II) species introduced to aerated water will occur primarily as the poorly soluble Sn(OH)2 species at environmentally-relevant pH. The pKa of 2 -ethylhexanoic acid is reported in several sources to be 4.8; however a specific reference which included methods of determination cannot be found. The results of the Key Study are consistent with the expected dissociation behaviour of 2 -ethylhexanoic acid.
Seby et al. (2001) report a dissociation constant of 1.74 for Sn(II)Cl2 in 3M NaClO4 solution. However, this publication also illustrates the spontaneous oxidation of Sn(II) in oxygenated water to form the insoluble Sn(IV)O2 solid. Therefore, the dissociation constant and water solubility of this insoluble species is not important for the environmental hazard assessment of tin bis(2 -ethylhexanoate).
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